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Objective: Gas embolism is a common complication of hysteroscopic surgery that causes serious concern among gynecologists and anesthesiologists due to the potential risk to patients. The factors influencing gas embolism in hysteroscopic surgery have been extensively studied. However, the effect of the oxygen concentration inhaled by patients on gas embolism during hysteroscopic surgery remains elusive. Therefore, we designed a double-blind, randomized, controlled trial to determine whether different inhaled oxygen concentrations influence the occurrence of gas embolism during hysteroscopic surgery., Methods: This trial enrolled 162 adult patients undergoing elective hysteroscopic surgery who were randomly divided into three groups with inspired oxygen fractions of 30%, 50%, and 100%. Transthoracic echocardiography (four-chamber view) was used to evaluate whether gas embolism occurred. Before the start of surgery, the four-chamber view was continuously monitored., Results: The number of gas embolisms in the 30%, 50%, and 100% groups was 36 (69.2%), 30 (55.6%), and 24 (44.4%), respectively. The incidence of gas embolism gradually decreased with increasing inhaled oxygen concentration (P = 0.031)., Conclusion: In hysteroscopic surgery, a higher oxygen concentration inhaled by patients may reduce the incidence of gas embolism, indicating that a higher inhaled oxygen concentration, especially 100%, could be recommended for patients during hysteroscopic surgery., Trial Registration: Chinese Clinical Trial Registry (https://www.chictr.org.cn/showproj.html?proj=53779, Registration number: ChiCTR2000033202)., (© 2023 International Federation of Gynecology and Obstetrics.)

Introduction: Gas embolism can occur during minimally invasive surgical procedures. Its incidence and implications in infants and children are not clear. The objective of this study is to identify gas embolism with transthoracic echocardiography and its consequences in pediatric laparoscopic appendectomy. Materials and Methods: This is a descriptive observational study including children undergoing laparoscopic appendectomy. We performed transthoracic echocardiography during surgery and collected data on intraoperative hemodynamic and respiratory parameters. Results: To date, we have included 10 patients in whom intraoperative transthoracic echocardiography revealed a 50% incidence of gas embolism. All episodes of embolism were grade I or II, and the patients remained asymptomatic. The hemodynamic and respiratory parameters varied slightly during the pneumoperitoneum. Conclusions: Episodes of gas embolism in pediatric laparoscopic appendectomy appeared in up to 50% of patients. Although they were subclinical, we should be aware of the risk of serious events and take measures to maximize safety in pediatric minimally invasive surgery.

To quantitatively analyze the risk factors for air embolism following computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) and qualitatively review their characteristics. The databases of PubMed, Embase, Web of Science, Wanfang Data, VIP information, and China National Knowledge Infrastructure were searched on January 4, 2021, for studies reporting the occurrence of air embolisms following CT-guided PTNB. After study selection, data extraction, and quality assessment, the characteristics of the included cases were qualitatively and quantitatively analyzed. A total of 154 cases of air embolism following CT-guided PTNB were reported. The reported incidence was 0.06% to 4.80%, and 35 (22.73%) patients were asymptomatic. An unconscious or unresponsive state was the most common symptom (29.87%). Air was most commonly found in the left ventricle (44.81%), and 104 (67.53%) patients recovered without sequelae. Air location ( P < 0.001), emphysema ( P = 0.061), and cough ( P = 0.076) were associated with clinical symptoms. Air location ( P = 0.015) and symptoms ( P < 0.001) were significantly associated with prognosis. Lesion location [odds ratio (OR): 1.85, P = 0.017], lesion subtype (OR: 3.78, P = 0.01), pneumothorax (OR: 2.16, P = 0.003), hemorrhage (OR: 3.20, P < 0.001), and lesions located above the left atrium (OR: 4.35, P = 0.042) were significant risk factors for air embolism. Based on the current evidence, a subsolid lesion, being located in the lower lobe, the presence of pneumothorax or hemorrhage, and lesions located above the left atrium were significant risk factors for air embolism.

Introduction: Breath-hold (BH) diving has known risks, for example drowning, pulmonary oedema of immersion and barotrauma. There is also the risk of decompression illness (DCI) from decompression sickness (DCS) and/or arterial gas embolism (AGE). The first report on DCS in repetitive freediving was published in 1958 and from then there have been multiple case reports and a few studies but no prior systematic review or meta-analysis., Methods: We undertook a systematic literature review to identify articles available from PubMed and Google Scholar concerning breath-hold diving and DCI up to August 2021., Results: The present study identified 17 articles (14 case reports, three experimental studies) covering 44 incidences of DCI following BH diving., Conclusions: This review found that the literature supports both DCS and AGE as potential mechanisms for DCI in BH divers; both should be considered a risk for this cohort of divers, just as for those breathing compressed gas while underwater., (Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.)

Purpose: The aim of the study is to analyze incidence and risk factors for air embolism during computed tomography (CT) fluoroscopy-guided lung biopsies using noncoaxial automatic needle., Materials and Methods: Between February 2014 and December 2019, 204 CT fluoroscopy-guided lung biopsies (127 men; mean age, 70.6 years) using noncoaxial automatic needle under inspiratory breath holding were performed. We retrospectively evaluated the incidence of air embolism as presence of air in the systemic circulation on whole-chest CT images obtained immediately after biopsy. Risk factors of the patient, tumor and procedural factors (size, location and type of nodule, distance from the pleura, the level of the lesion relative to the left atrium, emphysema, patient position, penetration of a pulmonary vein, etc) were analyzed., Results: The technical success rate was 97.1%. Air embolism was radiologically identified in 8 cases (3.92%, 7 males; size, 21.6 ± 18.2 mm; distance to pleura, 11.9 ± 14.5 mm). Two patients showed overt symptoms and the others were asymptomatic. Independent risk factors were needle penetration of the pulmonary vein ( P = 0.0478) and higher location relative to left atrium ( P = 0.0353). Size, location and type of nodule, distance from the pleura, emphysema, patient position, and other variables were not significant risk factors. As other complications, pneumothorax and alveolar hemorrhage were observed in 57.4% and 77.5%, respectively., Conclusions: In CT fluoroscopy-guided lung biopsy using the noncoaxial automatic needles, radiological incidence of air embolism was 3.92%. Given the frequency of air embolism, it is necessary to incorporate this into postprocedure imaging and clinical evaluation., Competing Interests: The authors declare no conflict of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Air embolism during laparoscopic surgery is a rare but feared complication in the pediatric population. The objective of this study was to identify rates of air embolus in pediatric patients during hospitalization for laparoscopic or open surgical procedures of the peritoneal cavity. Materials and Methods: Patients 0-18 years old within the Pediatric Health Information System who underwent a predefined, common inpatient laparoscopic or open surgical procedure involving the peritoneal cavity from 2015 to 2020 were studied. International Classification of Diseases, Tenth Revision, Clinical Modification diagnosis codes for air embolism were then searched among patients during the same admission. Firth logistic regression was used to compare rates of air embolism in open and laparoscopic cohorts and in patients >1 and ≤1 year. Results: Unadjusted rates of air embolism were higher in patients undergoing open compared with laparoscopic surgery (open: 9/45,080; 20.0/100,000 patients versus laparoscopic: 3/101,892; 2.9/100,000 patients). In patients ≤1 year (45,726), 2 patients undergoing open surgery (2/1,031; 9.5/100,000 patients) and all 3 patients undergoing laparoscopic surgery had an air embolism diagnosis (3/22,329; 13.4/100,000 patients). For laparoscopic surgery, a suggested lower relative risk (RR) of air embolism was demonstrated for children >1 year compared with children ≤1 year (RR: 0.05, P  = .05). Conclusion: Air embolism associated with common pediatric surgical procedures of the peritoneum is rare and patients undergoing laparoscopic and open surgery have similar risks for air embolism. Although rare, the risk should be considered during surgical planning and abdominal access, especially in children ≤1 year old.

Objective: To assess whether pulmonary vein injury is detectable on CT and associated with air embolism after percutaneous transthoracic needle biopsy (PTNB) in a tertiary referral hospital., Methods: Between January 2012 and November 2021, 11,691 consecutive CT-guided PTNBs in 10,685 patients were retrospectively evaluated. Air embolism was identified by reviewing radiologic reports. Pulmonary vein injury was defined as the presence of the pulmonary vein in the needle pathway or shooting range of the cutting needle with the presence of parenchymal hemorrhage. The association between pulmonary vein injury and air embolism was assessed using logistic regression analysis in matched patients with and without air embolism with a ratio of 1:4., Results: A total of 27 cases of air embolism (median age, 67 years; range, 48-80 years; 24 men) were found with an incidence of 0.23% (27/11,691). Pulmonary vein injury during the procedures was identifiable on CT in 24 of 27 patients (88.9%), whereas it was 1.9% (2/108) for matched patients without air embolism The veins beyond the target lesion (70.8% [17/24]) were injured more frequently than the veins in the needle pathway before the target lesion (29.2% [7/24]). In univariable and multivariable analyses, pulmonary vein injury was associated with air embolism (odds ratio, 485.19; 95% confidence interval, 68.67-3428.19, p <.001)., Conclusion: Pulmonary vein injury was detected on CT and was associated with air embolism. Avoiding pulmonary vein injury with careful planning of the needle pathway on CT may reduce air embolism risk., Key Points: • Pulmonary vein injury during CT-guided biopsy was identifiable on CT in most of the patients (88.9% [24/27]). • The veins beyond the target lesion (70.8% [17/24]) were injured more frequently than the veins in the needle pathway before the target lesion (29.2% [7/24]). • Avoiding the distinguishable pulmonary vein along the pathway or shooting range of the needle on CT may reduce the air embolism risk., (© 2022. The Author(s), under exclusive licence to European Society of Radiology.)

Background: At our institution, patients undergoing neurosurgical procedures in the posterior cranial fossa are placed either in the semisitting or in the supine position. The major risk of the semisitting positioning is a venous air embolism (VAE), which may, however, also occur in the supine position., Methods: In a prospective single-center study with 137 patients, we evaluated the occurrence of VAEs in patients in the supine and in the semisitting position during the period from January 2014 until April 2015. All patients were monitored for VAE by the use of a transesophageal echocardiography (TEE)., Results: In total, 50% of the patients experienced a VAE (56% of these patients underwent surgery in the semisitting and 11% in the supine position). In total, 86% of the VAEs were detected by the use of a TEE and did not lead to any changes in the end-expiratory CO 2 . We only observed VAEs with a decrease in end-expiratory CO 2 in the semisitting position. However, none of the patients had any hemodynamic changes due to the VAE., Conclusions: The semisitting position with TEE monitoring and a standardized protocol is a safe and advantageous technique, taking account of a significant rate of VAEs. VAEs also occur in the supine position, but less frequently., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Introduction: Venous air embolization (VAE) from IV lines is a risk with IV contrast administration. The incidence of VAE ranges from 7% to 23%. While life-threatening VAE is rare, there is the potential risk of serious cerebrovascular events from paradoxical systemic air embolization (SAE) in patients with congenital intracardiac shunts. CT coronary angiogram (CTCA) hypothetically carries a higher risk of VAE as it requires dual injections as compared to single bolus dose contrast used in CT chest (CTC). The aim of this study was to assess the risk of VAE using CTCA as compared to conventional CTC. The incidence of cardiac shunts and their association with paradoxical SAE were also investigated., Methods: A retrospective study was conducted at a tertiary hospital. Adult patients undergoing CTCA and CTC over a 6-month period in 2017 were included. Images were reviewed on PACS for the presence of VAE. Electronic medical records were interrogated for evidence of neurological sequelae or requiring neurological imaging (CTB/MRIB) within 1 month of the initial imaging., Results: 508 patients were included, 408 underwent CTCA and 100 underwent CTC. The VAE incidence in CTCA was 24% (94 patients) and 10% in the CTC (10 patients). This was statistically significant. Among the CTCA group, 36% (108 patients) had an intracardiac shunt. No statistically significant difference in VAE incidence was identified in CTCA patients with shunts vs without shunts. There was no incidence of SAE in both groups., Conclusion: VAE is more common with CTCA than conventional CTC. There were no cases of paradoxical SAE found., (© 2021 The Royal Australian and New Zealand College of Radiologists.)

Sea turtles that are entrapped in static and towed nets may develop gas embolism which can lead to severe organ injury and death. Trawling characteristics, physical and physiologic factors associated with gas-embolism and predictors of mortality were analysed from 482 bycaught loggerheads. We found 204 turtles affected by gas-embolism and significant positive correlations between the presence of gas-embolism and duration, depth, ascent rate of trawl, turtle size and temperature, and between mortality and ascent time, neurological deficits, significant acidosis and involvement of > 12 cardiovascular sites and the left atrium and sinus venosus-right atrium. About 90% turtles with GE alive upon arrival at Sea Turtle Clinic recovered from the disease without any supportive drug therapy. Results of this study may be useful in clinical evaluation, prognostication, and management for turtles affected by gas-embolism, but bycatch reduction must become a priority for major international organizations. According to the results of the present study the measures to be considered to reduce the catches or mortality of sea turtles for trawling are to be found in the modification of fishing nets or fishing operations and in greater awareness and education of fishermen., (© 2021. The Author(s).)

Background: Surveillance of maternal mortality and severe maternal morbidity is important to identify temporal trends, evaluate the impact of clinical practice changes or interventions, and monitor quality of care. A common source for severe maternal morbidity surveillance is hospital discharge data. On October 1, 2015, all hospitals in the United States transitioned from the International Classification of Diseases, Ninth Revision, Clinical Modification to the International Classification of Diseases, Tenth Revision, Clinical Modification coding for diagnoses and procedures., Objective: This study aimed to evaluate the impact of the transition from the International Classification of Diseases, Ninth Revision, Clinical Modification to the International Classification of Diseases, Tenth Revision, Clinical Modification coding systems on the incidence of severe maternal morbidity in the United States in hospital discharge data., Study Design: Using data from the National Inpatient Sample, obstetrical deliveries between January 1, 2012, and December 31, 2017, were identified using a validated case definition. Severe maternal morbidity was defined using the International Classification of Diseases, Ninth Revision, Clinical Modification (January 1, 2012, to September 30, 2015) and the International Classification of Diseases, Tenth Revision, Clinical Modification (October 1, 2015, to December 31, 2017) codes provided by the Centers for Disease Control and Prevention. An interrupted time series and segmented regression analysis was used to assess the impact of the transition from the International Classification of Diseases, Ninth Revision, Clinical Modification to the International Classification of Diseases, Tenth Revision, Clinical Modification coding on the incidence of severe maternal morbidity per 1000 obstetrical deliveries., Results: From 22,751,941 deliveries, the incidence of severe maternal morbidity in the International Classification of Diseases, Ninth Revision, Clinical Modification coding era was 19.04 per 1000 obstetrical deliveries and decreased to 17.39 per 1000 obstetrical deliveries in the International Classification of Diseases, Tenth Revision, Clinical Modification coding era (P<.001). The transition to International Classification of Diseases, Tenth Revision, Clinical Modification coding led to an immediate decrease in the incidence of severe maternal morbidity (-2.26 cases of 1000 obstetrical deliveries) (P<.001). When blood products transfusion was removed from the case definition, the magnitude of the decrease in the incidence of SMM was much smaller (-0.60 cases/1000 obstetric deliveries), but still significant (P<.001)., Conclusion: After the transition to the International Classification of Diseases, Tenth Revision, Clinical Modification coding for health diagnoses and procedures in the United States, there was an abrupt statistically significant and clinically meaningful decrease in the incidence of severe maternal morbidity in hospital discharge data. Changes in the underlying health of the obstetrical population are unlikely to explain the sudden change in severe maternal morbidity. Although much work has been done to validate the International Classification of Diseases, Ninth Revision, Clinical Modification codes for severe maternal morbidity, it is critical that validation studies be undertaken to validate the International Classification of Diseases, Tenth Revision, Clinical Modification codes for severe maternal morbidity to permit ongoing surveillance, quality improvement, and research activities that rely on hospital discharge data., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The goal of Pressurized Submarine Escape Training (PSET) is to prepare future submariners for the physical and mental challenges of escaping a disabled submarine and promote proper handling of the Beaufort Ltd Mk 11 Submarine Escape and Immersion Equipment suit. Training participants are only permitted to enter PSET after strict health screening protocols have been met to optimize trainees' safety. Before PSET, trainees are given detailed, one-on-one instruction on proper ascent mechanics by specially trained Navy Dive instructors. Since the reinstatement of PSET by the U.S. Navy, four incidents of arterial gas embolism (AGE) have occurred in submarine trainees with a 10-year period (2009-2019). Of these four incidents, three were observed within a couple months of each other from 2018 to 2019. A comprehensive review of AGE history, epidemiology, dive physiology, pathophysiology, and management was completed. Prompted by the recent incidents relative to the low reported incidence rate of AGE in historical PSET training, reported potential risk factors were compared with better understand potential etiologies of AGE in already medically screened individuals. Risks and benefits of PSET were listed, compared, and analyzed. The relative safety and cost effectiveness of this rigorous form of training was reconfirmed., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2020. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Objectives: To determine the incidence, risk factors, and prognostic indicators of symptomatic air embolism after percutaneous transthoracic lung biopsy (PTLB) by conducting a systematic review and pooled analysis., Methods: We searched the EMBASE and OVID-MEDLINE databases to identify studies that dealt with air embolism after PTLB and had extractable outcomes. The incidence of air embolism was pooled using a random effects model, and the causes of heterogeneity were investigated. To analyze risk factors for symptomatic embolism and unfavorable outcomes, multivariate logistic regression analysis was performed., Results: The pooled incidence of symptomatic air embolism after PTLB was 0.08% (95% confidence interval [CI], 0.048-0.128%; I 2  = 45%). In the subgroup analysis and meta-regression, guidance modality and study size were found to explain the heterogeneity. Of the patients with symptomatic air embolism, 32.7% had unfavorable outcomes. The presence of an underlying disease (odds ratio [OR], 5.939; 95% CI, 1.029-34.279; p = 0.046), the use of a ≥ 19-gauge needle (OR, 10.046; 95% CI, 1.103-91.469; p = 0.041), and coronary or intracranial air embolism (OR, 19.871; 95% CI, 2.725-14.925; p = 0.003) were independent risk factors for symptomatic embolism. Unfavorable outcomes were independently associated with the use of aspiration biopsy rather than core biopsy (OR, 3.302; 95% CI, 1.149-9.492; p = 0.027) and location of the air embolism in the coronary arteries or intracranial spaces (OR = 5.173; 95% CI = 1.309-20.447; p = 0.019)., Conclusion: The pooled incidence of symptomatic air embolism after PTLB was 0.08%, and one-third of cases had sequelae or died. Identifying whether coronary or intracranial emboli exist is crucial in suspected cases of air embolism after PTLB., Key Points: • The pooled incidence of symptomatic air embolism after percutaneous transthoracic lung biopsy was 0.08%, and one-third of patients with symptomatic air embolism had sequelae or died. • The risk factors for symptomatic air embolism were the presence of an underlying disease, the use of a ≥ 19-gauge needle, and coronary or intracranial air embolism. • Sequelae and death in patients with symptomatic air embolism were associated with the use of aspiration biopsy and coronary or intracranial locations of the air embolism.

Importance: Previous efforts to examine severe maternal morbidity (SMM) in the US have focused on delivery hospitalizations. Little is known about de novo SMM that occurs after delivery discharge., Objective: To investigate the incidence, timing, factors, and maternal characteristics associated with de novo SMM after delivery discharge among women in the US., Design, Setting, and Participants: In this retrospective cohort study, data from the IBM MarketScan Multi-State Medicaid database and the IBM MarketScan Commercial Claims and Encounters database were used to construct a sample of women aged 15 to 44 years who delivered between January 1, 2010, and September 30, 2014. Severe maternal morbidity was reported by the timing of diagnosis, and the associated maternal characteristics were examined. Women in the Medicaid and commercial insurance sample were classified into 3 distinct outcome groups: (1) those without any SMM during the delivery hospitalization and the postdelivery period (reference group), (2) those who exhibited at least 1 factor associated with SMM during the delivery hospitalization, and (3) those who exhibited any factor associated with de novo SMM after delivery discharge (defined as SMM that was first diagnosed in the inpatient setting during the 6 weeks [or 42 days] after discharge from the delivery hospitalization, conditional on no factor associated with SMM being identified during delivery). Data were analyzed from February to July 2020., Exposures: Timing of SMM diagnosis., Main Outcomes and Measures: Women with SMM were identified using diagnosis and procedure codes from the International Classification of Diseases, Ninth Revision, Clinical Modification for the 21 factors associated with SMM that were developed by the Centers for Disease Control and Prevention., Results: A total of 2 667 325 women in the US with delivery hospitalizations between 2010 and 2014 were identified; of those, 809 377 women (30.3%) had Medicaid insurance (30.3%; mean [SD] age, 25.6 [5.5] years; 51.1% White), and 1 857 948 women (69.7%; mean [SD] age, 30.6 [5.4] years; 36.4% from the southern region of the US) had commercial insurance. Among those with Medicaid insurance, 17 584 women (2.2%) experienced SMM during the delivery hospitalization, and 3265 women (0.4%) experienced de novo SMM after delivery discharge. Among those with commercial insurance, 32 079 women (1.7%) experienced SMM during the delivery hospitalization, and 5275 women (0.3%) experienced de novo SMM after hospital discharge. A total of 5275 SMM cases (14.1%) and 3265 SMM cases (15.7%) among women with commercial and Medicaid insurance, respectively, developed de novo within 6 weeks after hospital discharge; of those, 3993 cases (75.7%) in the commercial insurance cohort and 2399 cases (73.5%) in the Medicaid cohort were identified in the first 2 weeks after discharge. The most common factors associated with SMM varied based on the timing of diagnosis. In the Medicaid population, non-Hispanic Black women (adjusted odds ratio [aOR], 1.53; 95% CI, 1.48-1.58), Hispanic women (aOR, 1.46; 95% CI, 1.37-1.57), and women of other races or ethnicities (aOR, 1.40; 95% CI, 1.33-1.47) had higher rates of SMM during delivery hospitalization than non-Hispanic White women; however, only the disparity between Black and White women (aOR, 1.69; 95% CI, 1.57-1.81) persisted into the postdischarge period., Conclusions and Relevance: In this study, 15.7% of SMM cases in the Medicaid cohort and 14.1% of SMM cases in the commercial insurance cohort first occurred after the delivery hospitalization, with notable disparities in factors and maternal characteristics associated with the development of SMM. These findings suggest a need to expand the focus of SMM assessment to the postdelivery discharge period.

Multiday hyperbaric exposure has been shown to reduce the incidence of decompression sickness (DCS) of compressed-air workers. This effect, termed acclimatization, has been addressed in a number of studies, but no comprehensive review has been published. This systematic review reports the findings of a literature search. PubMed, Ovid Embase, The Cochrane Library and Rubicon Research Repository were searched for studies reporting DCS incidence, venous gas embolism (VGE) or subjective health reports after multiday hyperbaric exposure in man and experimental animals. Twenty-nine studies fulfilled inclusion criteria. Three epidemiological studies reported statistically significant acclimatization to DCS in compressed-air workers after multiday hyperbaric exposure. One experimental study observed less itching after standardized simulated dives. Two human experimental studies reported lower DCS incidence after multiday immersed diving. Acclimatization to DCS has been observed in six animal species. Multiday diving had less consistent effect on VGE after hyperbaric exposure in man. Four studies observed acclimatization while no statistically significant acclimatization was reported in the remaining eight studies. A questionnaire study did not report any change in self-perceived health after multiday diving. This systematic review has not identified any study suggesting a sensitizing effect of multiday diving, and there is a lack of data supporting benefit of a day off diving after a certain number of consecutive diving days. The results suggest that multiday hyperbaric exposure probably will have an acclimatizing effect and protects from DCS. The mechanisms causing acclimatization, extent of protection and optimal procedure for acclimatization has been insufficiently investigated., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Aim: To evaluate whether preflushing before connecting a power injector to a patient's catheter reduces the incidence of venous air embolism (VAE) in contrast-enhanced computed tomography (CT) angiography (CTA)., Materials and Methods: With the approval from the local ethics committee, consecutive patients were divided randomly into a control group and a preflushing group and underwent CTA from June to November 2017. The control group underwent the conventional injection procedure. In the preflushing group, the injector tubes were flushed at high speed (10 ml/s) with saline before being connected to the patients' indwelling catheters. The locations, number, and sizes of VAE were analysed. The difference in the incidence of VAE between the two groups was compared., Results: A total of 4,900 adults (control/preflushing, 2,190/2,710) were included and 228 (4.65%) patients were found to have 318 VAEs (285 bubbles and 33 gas-liquid plane VAEs). The incidence of VAE in the preflushing group (3.21%) was lower than that in the control group (6.44%); a similar trend was observed for multiple VAEs (p<0.05). VAEs occurred in the following locations from high to low frequency: right atrium>pulmonary artery trunk>superior vena cava>right ventricle>left brachial vein>right brachial vein. There was no significant difference in the location, shape, or diameters (p=0.19) of VAEs between the two groups., Conclusions: The proposed preflushing procedure is simple yet effective in reducing the incidence of VAE by 50.16% in patients with CTA, thus improving safety during power injection., (Copyright © 2020 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Objective: To assess the association between total volume and number of gaseous microemboli (GME) in the cardiopulmonary bypass (CPB) circuit and the occurrence of new postoperative cerebral infarctions and postoperative cognitive dysfunction (POCD) in patients undergoing cardiac surgery., Design: Predefined subanalyses of the randomized controlled Perfusion Pressure Cerebral Infarcts (PPCI) trial., Setting: Primary heart center in a university hospital., Participants: A total of 143 adult patients undergoing cardiac surgery with CPB., Interventions: Patients were allocated 1:1 to a low-target mean arterial pressure (MAP) of 40 to 50 mmHg or a high-target MAP of 70 to 80 mmHg during CPB with a fixed pump flow of 2.4 liters per minute per square meter body surface area plus 10% to 20%., Measurements and Main Results: The total volume and number of GME in the CPB circuit were assessed by the Bubble Counter Clinical 200® (GAMPT GmbH). New cerebral infarcts were identified by diffusion-weighted magnetic resonance imaging (DWI) 3 to 6 days after surgery. The median number of GME per patient was 8069 (range 1,523-204,095) with a median total volume of 1.2 μL (range 0.07-48 μL). A total of 66 (46%) patients had DWI detected cerebral infarcts postoperatively, and 36 (28%) patients had POCD after 7 days. The authors found no significant association between volume or number of GME with MAP target allocation, presence of cerebral infarction, or POCD., Conclusions: The authors found no significant associations between volume or number of GME with the occurrence of cerebral infarction or cognitive dysfunction in cardiac surgery patients., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Extremely preterm infants are peculiar in regard to their risk of retinopathy of prematurity (ROP). In this study, we aim to study insults that may affect extremely preterm infants, including prenatal, at birth, and postnatal insults and their effect on the development of ROP., Methods: This study used the data from Prematurity and Respiratory Outcomes Program (PROP). All included infants with a gestational age of 23 0/7 to 28 6/7 weeks using best obstetrical estimate. We included stressful events and/or modifiable variables that may affect the normal development. We used multiple regression analysis in our statistical analysis., Results: We included a total of 751 infants in our study. The mean birth weight for the included sample was 915.1 (±232.94) grams. 391 (52.1%) Infants were diagnosed with ROP. We found a significant negative correlation between ROP development and birth weight (p < 0.001), with a correlation coefficient of - 0.374. We found that the need for prophylactic indomethacin (OR 1.67), the occurrence of air leaks (OR: 2.35), ventilator-associated pneumonia (OR: 2.01), isolated bowel perforations (OR: 3.7), blood culture-proven sepsis (OR: 1.5), other infections (OR: 1.44), and receiving ventricular shunt (OR: 2.9) are significantly associated with the development of ROP., Conclusions: We believe this study included the largest number of factors studied in the largest sample of extremely premature infants. We recommend a screening program for extremely preterm infants that takes into account a scoring system with higher scores for complicated condition.

Background: Air embolism is an extremely rare complication that can follow gastrointestinal endoscopy. The most accepted treatment of cerebral air embolism (CAE) is hyperbaric oxygen (HBO). Limited evidence suggests that lidocaine may have a neuroprotective effect. The exact mechanism does not appear to be well elucidated., Methods: We conducted a literature search using multiple combinations of keywords from PubMed and Ovid Medline databases according to the PRISMA guidelines. We included articles with cases of air embolism caused by an esophagogastroduodenoscopy (EGD). We excluded cases related to other procedures e.g. colonoscopy, endoscopic retrograde cholangiopancreatography, cholangioscopy, Kasai procedure, bronchoscopy, laparoscopy or thoracoscopy. We were able to identify 30 cases of CAE associated with EGD. We included our experience in treating one patient with CAE after elective EGD., Results: Given the results of our literature search and this patient's characteristics, we chose to treat our patient with HBO and lidocaine infusion. Our case series consists of 31 patients of post EGD CAE, the mean age was 63.7 ± 11.14 years, 38.7% of the patients were women (n = 12). 38.7% of the cases underwent esophageal dilatation (n = 12), while 19.35% had EGD biopsy (n = 6), 9.6% had variceal ligation (n = 3), and 3.22% had variceal banding (n = 1). In 20 out of 31 cases, echocardiography has been documented, 20% of those patients (n = 4) had patent foramen ovale. HBO was used in treatment of 48% of cases (n = 15), among the included patients, 61% survived (n = 19). Our patient showed significant neurological improvement., Conclusions: Despite the rare incidence of CAE during or after EGD, physicians should be aware of this potential complication. In patients who develop sudden acute neurological symptoms, early diagnosis and intervention may prevent devastating neurological injury and death. The most accepted emergent treatment for CAE includes HBO, consideration of lidocaine, and work-up of source of the air embolism., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Venous air embolism (VAE) can be observed in the right heart system on contrast-enhanced computed tomography (CT), following injection of contrast media with a power injector system. Although most VAEs are mostly asymptomatic, they may result in paradoxical air embolism (PAE).To evaluate whether the incidence of VAE on coronary CT angiography is associated with the process of preparation of the intravenous access route.We retrospectively evaluated 692 coronary CT examinations at 3 institutions. Trained CT nurses placed an intravenous cannula in the forearm. Tubes connected to the cannula were prepared in the following ways: A, using an interposed three-way cock and a 20-mL syringe filled with normal saline to collect air contamination in the tube; B, through direct connection to the power injector system without the interposed 3-way cock; and C, using an interposed three-way cock and a 100-mL normal saline drip infusion bottle system to keep the tube patent. The incidence and location of VAE and preparation of intravenous injection were assessed.The overall incidence of VAE was 55.3% (383/692), most frequently observed in the right atrium (81.5%, 312/383). Its incidence varied significantly across the 3 techniques (A: 21.6% (35/162), B: 63.2% (237/375) and C: 71.6% (111/155); P < .001). No patient demonstrated any symptom associated with VAE.Using a 3-way cock with syringe demonstrated the lowest incidence of VAE on coronary CT angiography. It is thus recommended to reduce potential complication risks related to intravenous contrast media injection.

Background: Arterial gas embolus (AGE) is a rare complication of esophagoduodenoscopy (EGD) that has been described in only a few case reports in the literature. The exact etiology remains unknown, but many of the cases share some common characteristics., Case Report: We report the case of a 52-year-old otherwise healthy man who underwent outpatient EGD for a sensation of retained food in his esophagus. During the procedure, he suffered a tonic-clonic seizure, bradycardia, and hypoxia. Subsequent emergency department workup showed pneumocephalus on computed tomography brain imaging, and he was diagnosed with a cerebral AGE (CAGE). He was transferred to our facility for treatment of CAGE with hyperbaric oxygen therapy (HBOT). After multiple hyperbaric treatments, he was discharged with a residual left hemiparesis, which represented a significant improvement in his overall neurologic status. We also present a review of similar EGD CAGE cases from the literature and discuss their outcomes and the need for HBOT. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Although CAGE from EGD is rare, these patients will often be transferred to the ED from gastrointestinal procedural suites and an emergency physician should understand that an iatrogenic CAGE can result from this procedure and that CAGE is a clinical diagnosis. Definitive care at a critical care-capable hyperbaric chamber will provide the patient with the best chance of meaningful recovery, and transport should be arranged as expeditiously as possible., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Venous air embolism (VAE) is a well-described complication of neurosurgical procedures performed in the seated position. Although most often clinically insignificant, VAE may result in hemodynamic or neurological compromise resulting in urgent change to a level position. The incidence, intraoperative course, and outcome in such patients are provided in this large retrospective study., Methods: Patients undergoing a neurosurgical procedure in the seated position at a single institution between January 2000 and October 2013 were identified. Corresponding medical records, neurosurgical operative reports, and computerized anesthetic records were searched for intraoperative VAE diagnosis. Extreme VAE was defined as a case in which urgent seated to level position change was performed for patient safety. Detailed examples of extreme VAE cases are described, including their intraoperative course, VAE management, and postoperative outcomes., Results: There were 8 extreme VAE (0.47% incidence), 6 during suboccipital craniotomy (1.5%) and 2 during deep brain stimulator implantation (0.6%). VAE-associated end-expired CO2 and mean arterial pressure reductions rapidly normalized following position change. No new neurological deficits or cardiac events associated with extreme VAE were observed. In 5 of 8, surgery was completed. Central venous catheter placement and aspiration during VAE played no demonstrable role in patient outcome., Conclusions: Extreme VAE during seated intracranial neurosurgical procedures is infrequent. Extreme VAE-associated CO2 exchange and hemodynamic consequences from VAE were transient, recovering quickly back to baseline without significant neurological or cardiopulmonary morbidity.

INTRODUCTION: The frequency of long-duration, high-altitude missions with fighter aircraft is increasing, which may increase the incidence of decompression sickness (DCS). The aim of the present study was to compare decompression stress during simulated sustained high-altitude flying vs. high-altitude flying interrupted by periods of moderate or marked cabin pressure increase. METHODS: The level of venous gas emboli (VGE) was assessed from cardiac ultrasound images using the 5-degree Eftedal-Brubakk scale. Nitrogen washout/uptake was measured using a closed-circuit rebreather. Eight men were investigated in three conditions: one 80-min continuous exposure to a simulated cabin altitude of A) 24,000 ft, or four 20-min exposures to 24,000 ft interspersed by three 20-min intervals at B) 20,000 ft or C) 900 ft. RESULTS: A and B induced marked and persistent VGE, with peak bubble scores of [median (range)]: A: 2.5 (1-3); B: 3.5 (2-4). Peak VGE score was less in C [1.0 (1-2), P < 0.01]. Condition A exhibited an initially high and exponentially decaying rate of nitrogen washout. In C the washout rate was similar in each period at 24,000 ft, and the nitrogen uptake rate was similar during each 900-ft exposure. B exhibited nitrogen washout during each period at 24,000 ft and the initial period at 20,000 ft, but on average no washout or uptake during the last period at 20,000 ft. DISCUSSION: Intermittent reductions of cabin altitude from 24,000 to 20,000 ft do not appear to alleviate the DCS risk, presumably because the pressure increase is not sufficient to eliminate VGE. The nitrogen washout/uptake rate did not reflect DCS risk in the present exposures. Ånell R, Grönkvist M, Eiken O, Gennser M. Nitrogen washout and venous gas emboli during sustained vs. discontinuous high-altitude exposures . Aerosp Med Hum Perform. 2019; 90(6):524-530.

Background: Cerebral gas embolism is a complication of several medical procedures and occurs when gas enters the cerebral circulation. Knowledge about etiology and outcome in affected patients is limited, and prospective trials on management and treatment are hardly feasible. Case reports are therefore an important source of information., Methods: A systematic literature search was conducted in June 2016 and May 2018, supplemented by a manual search. Titles and abstracts were systematically assessed for eligibility, followed by full-text screening for included papers. Screening and data extraction were performed independently by two researchers. Cases of cerebral gas embolism due to any iatrogenic cause were included. Criteria for exclusion were: animal studies, non-cerebral localization, extravascular gas only, and non-iatrogenic causes. 264 cases reported in 189 papers were included., Results: A broad range of procedures leading to iatrogenic cerebral gas embolism (ICGE) were identified and a comprehensive list is presented in this article. Procedures were mostly reported as conducted correctly, but procedure related error, patient activity, or defective equipment were also reported as causes. Neurological, neuropsychological, and cardiopulmonary symptoms were common. The diagnosis was frequently based on or confirmed by radiology, usually CT. Hyperbaric oxygen therapy was applied in a large number of cases., Conclusion: The reported causes, symptoms and signs, and outcomes of ICGE vary significantly, and awareness of the condition in the medical community is essential. A standardized method of reporting could facilitate higher quality research in the field., (© 2018 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Objective: To evaluate the hospital-acquired condition (HAC) following oophorectomy and/or hysterectomy for gynecologic cancer patients based on clinical outcomes and costs., Materials and Methods: Data were obtained from the Nationwide Inpatient Sample from 2005 to 2011. Chi-squared and Wilcoxon rank sum two-sample tests and multivariate logistic regression model were used for statistical analysis., Results: Of 82,304 women (median age: 60 years, range: 1-101), 49,386 (60.0%) had endometrial, 23,510 (28.6%) had ovarian, and 9408 (11.4%) had cervical cancers. Of 135 HAC events, these involved catheter-associated urinary tract infections (n = 47), vascular catheter-associated infection (n = 41), foreign object retained after surgery (n = 19), pressure ulcers (n = 16), manifestation of poor glycemic control (n = 10), and air embolism (n = 2). Older patients (≥60 years) experienced more HACs relative to younger (0.23% vs. 0.09%; OR = 2.13, 95% CI: 1.30-3.50; p = 0.003), and patients with Medicaid experienced more HACs compared to those with private insurance (0.35% vs. 0.10%; OR = 3.09, 95% CI: 1.70-5.62; p < 0.001). Laparoscopic surgeries were associated with less HACs compared to open surgeries (0.05% vs. 0.19%; OR = 0.41, 95% CI: 0.19-0.90; p = 0.03). Length of hospitalization and hospital charges were greater for those with HACs, (12 days vs. 3 days; p < 0.001; $89,324 vs. $31,107; p < 0.001), respectively., Conclusion: The odds of hospital-acquired conditions were higher in older patients, open surgery, Medicaid insured with higher associated hospital charges., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Known complications of endoscopic retrograde cholangiopancreatography (ERCP) include pancreatitis, bleeding, duodenal perforation, and venous air embolism (VAE). The aim of this study was to determine the incidence of VAE during ERCP and be able to differentiate high-risk versus low-risk ERCP procedures., Methods: This is a prospective cohort study consisting of patients who underwent ERCP and were monitored with a precordial Doppler ultrasound (PDU) for VAE. PDU monitoring was digitally recorded and analyzed to confirm the suspected VAE. Demographic and clinical data related to the anesthetic care, endoscopic procedure, and intraoperative hemodynamics were analyzed., Results: A total of 843 ERCP procedures were performed over a 15-month period. The incidence of VAE was 2.4% (20 patients). All VAE's occurred during procedures in which stent placement, sphincterotomy, biopsy, duct dilation, gallstone retrieval, cholangioscopy, or necrosectomy occurred. Ten of 20 (50%) of VAEs were associated with hemodynamic alterations. None occurred if the procedure was only diagnostic or for stent removal. Subanalysis for the type of procedure showed that VAE was statistically more frequent when stents were removed and then replaced or if a cholangioscopy was performed., Conclusions: The high incidence of VAE highlights the need for practitioners to be aware of this potentially serious event. Use of PDU can aid in the detection of VAE during ERCP and should be considered especially during high-risk therapeutic procedures. Detection may allow appropriate interventions before serious adverse events such as cardiovascular collapse occur.

OBJECTIVE The semisitting position of a patient confers numerous advantages in various neurosurgical procedures, but venous air embolism is one of the associated complications of this position. To date, no prospective studies of the relationship between the degree of head elevation and the rate and severity of venous air embolism for patients undergoing a procedure in this position have been performed. In this study, the authors compared changes in the severity of venous air embolism according to the degree of head elevation (30° or 45°) in patients undergoing an elective cranial neurosurgical procedure in the semisitting position. METHODS One hundred patients undergoing an elective infratentorial craniotomy in the semisitting position were included, and each patient was assigned to 1 of 2 groups. In Group 1, each patient's head was elevated 30° during surgery, and in Group 2, each patient's head elevation was 45°. Patients were assigned to their group according to the location of their lesion. During surgery, the standard anesthetic protocol was used with total intravenous anesthesia, and transesophageal echocardiography was used to detect air in the blood circulation. Any air embolism seen on the echocardiography screen was classified as Grade 0 to 4. If multiple events occurred, the worst graded attack was used for statistical analysis. During hemodynamic changes caused by emboli, fluid and vasopressor requirements were recorded. Surgical and anesthetic complications were recorded also. All results were compared statistically, and a p value of < 0.05 was considered statistically significant. RESULTS There was a statistically significant difference between groups for the total rates of venous air emboli detected on transesophageal echocardiography (22.0% [n = 11] in Group 1 and 62.5% [n = 30] in Group 2; p < 0.0001). The rate and severity of air embolism were significantly lower in Group 1 than in Group 2 (p < 0.001). The rates of clinically important venous air embolism (Grade 2, 3, or 4, venous air embolism with decreased end-tidal carbon dioxide levels and/or hemodynamic changes) were 8.0% (n = 4) in Group 1 and 50.0% (n = 24) in Group 2 (p < 0.0001). There was no association between the rate and severity of venous air embolism with patient demographics (p > 0.05). An association was found, however, between the rate of venous air embolism and the type of surgical pathology (p < 0.001); venous embolism occurred more frequently in patients with a meningioma. There were no major surgical or anesthetic complications related to patient position during the postoperative period. CONCLUSIONS For patients in the semisitting position, an increase in the degree of head elevation is related directly to a higher rate of venous air embolism. With a 30° head elevation and our standardized technique of positioning, the semisitting position can be used safely in neurosurgical practice.

Prolonged use of venoarterial extracorporeal membrane oxygenation (VA ECMO) may be complicated by end-organ dysfunction. Although gaseous microemboli (GME) are thought to damage end organs during cardiopulmonary bypass, patient exposures to GME have not been well characterized during VA ECMO. We therefore performed an observational study of GME in adult VA ECMO patients, with correlation to clinical events during routine patient care. After institutional review board (IRB) approval, we used two Doppler probes to detect GME noninvasively in extracorporeal membrane oxygenation (ECMO) circuits on four patients for 15 hours total while also recording patient care events. We then conducted in vitro trials to compare Doppler signals with gold-standard measurements using an Emboli Detection and Classification EDAC quantifier (Luna Innnovations, Inc. Roanoke, VA) (Terumo Cardiovascular, Ann Arbor, MI) during simulated clinical interventions. Correlations between Doppler and EDAC data were used to estimate GME counts and volumes represented by clinical Doppler data. A total of 503 groups of Doppler peaks representing GME showers were observed, including 194 statistically larger showers during patient care activities containing 92% of total Doppler peaks. Intravenous injections accounted for an estimated 68% of GME and 88% of GME volume, whereas care involving movement accounted for an estimated 6% of GME and 3% of volume. Overall estimated embolic rates of 24,000 GME totaling 4 μl/hr rivals reported GME rates during cardiopulmonary bypass. Numerous GME are present in the postmembrane circuit during VA ECMO, raising concern for effects on microcirculation and organ dysfunction. Strategies to detect and minimize GME may be warranted to limit embolic exposures experienced by VA ECMO patients.

Inadvertent exposure to radiation, chemical agents and biological factors are well recognized hazards associated with the health care delivery system. Less well appreciated yet no less harmful is risk of decompression sickness in those who accompany patients as inside attendants (IAs) during provision of hyperbaric oxygen therapy. Unlike the above hazards where avoidance is practiced, IA exposure to decompression sickness risk is unavoidable. While overall incidence is low, when calculated as number of cases over number of exposures or potential for a case during any given exposure, employee cumulative risk, defined here as number of cases over number of IAs, or risk that an IA may suffer a case, is not. Commonly, this unique occupational environmental injury responds favorably to therapeutic recompression and a period of recuperation. There are, however, permanent and career-ending consequences, and at least two nurses have succumbed to their decompression insults. The intent of this paper is to heighten awareness of hyperbaric attendant decompression sickness. It will serve as a review of reported cases and reconcile incidence against largely ignored individual worker risk. Mitigation strategies are summarized and an approach to more precisely identify risk factors that might prompt development of consensus screening standards is proposed., Competing Interests: The author of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

OBJECTIVE Historically, performing neurosurgery with the patient in the sitting position offered advantages such as improved visualization and gravity-assisted retraction. However, this position fell out of favor at many centers due to the perceived risk of venous air embolism (VAE) and other position-related complications. Some neurosurgical centers continue to perform sitting-position cases in select patients, often using modern monitoring techniques that may improve procedural safety. Therefore, this paper reports the risks associated with neurosurgical procedures performed in the sitting position in a modern series. METHODS The authors reviewed the anesthesia records for instances of clinically significant VAE and other complications for all neurosurgical procedures performed in the sitting position between January 1, 2000, and October 8, 2013. In addition, a prospectively maintained morbidity and mortality log of these procedures was reviewed for instances of subdural or intracerebral hemorrhage, tension pneumocephalus, and quadriplegia. Both overall and specific complication rates were calculated in relation to the specific type of procedure. RESULTS In a series of 1792 procedures, the overall complication rate related to the sitting position was 1.45%, which included clinically significant VAE, tension pneumocephalus, and subdural hemorrhage. The rate of any detected VAE was 4.7%, but the rate of VAE requiring clinical intervention was 1.06%. The risk of clinically significant VAE was highest in patients undergoing suboccipital craniotomy/craniectomy with a rate of 2.7% and an odds ratio (OR) of 2.8 relative to deep brain stimulator cases (95% confidence interval [CI] 1.2-70, p = 0.04). Sitting cervical spine cases had a comparatively lower complication rate of 0.7% and an OR of 0.28 as compared with all cranial procedures (95% CI 0.12-0.67, p < 0.01). Sitting cervical cases were further subdivided into extradural and intradural procedures. The rate of complications in intradural cases was significantly higher (OR 7.3, 95% CI 1.4-39, p = 0.02) than for extradural cases. The risk of VAE in intradural spine procedures did not differ significantly from sitting suboccipital craniotomy/craniectomy cases (OR 0.69, 95% CI 0.09-5.4, p = 0.7). Two cases (0.1%) had to be aborted intraoperatively due to complications. There were no instances of intraoperative deaths, although there was a single death within 30 days of surgery. CONCLUSIONS In this large, modern series of cases performed in the sitting position, the complication rate was low. Suboccipital craniotomy/craniectomy was associated with the highest risk of complications. When appropriately used with modern anesthesia techniques, the sitting position provides a safe means of surgical access.

Background: Continuous venovenous hemodialysis (CVVHD) may generate microemboli that cross the pulmonary circulation and reach the brain. The aim of the present study was to quantify (load per time interval) and qualify (gaseous vs. solid) cerebral microemboli (CME), detected as high-intensity transient signals, using transcranial Doppler ultrasound., Materials and Methods: Twenty intensive care unit (ICU group) patients requiring CVVHD were examined. CME were recorded in both middle cerebral arteries for 30 minutes during CVVHD and a CVVHD-free interval. Twenty additional patients, hospitalized for orthopedic surgery, served as a non-ICU control group. Statistical analyses were performed using the Mann-Whitney U test or the Wilcoxon matched-pairs signed-rank test, followed by Bonferroni corrections for multiple comparisons., Results: In the non-ICU group, 48 (14.5-169.5) (median [range]) gaseous CME were detected. In the ICU group, the 67.5 (14.5-588.5) gaseous CME detected during the CVVHD-free interval increased 5-fold to 344.5 (59-1019) during CVVHD (P<0.001). The number of solid CME was low in all groups (non-ICU group: 2 [0-5.5]; ICU group CVVHD-free interval: 1.5 [0-14.25]; ICU group during CVVHD: 7 [3-27.75])., Conclusions: This observational pilot study shows that CVVHD was associated with a higher gaseous but not solid CME burden in critically ill patients. Although the differentiation between gaseous and solid CME remains challenging, our finding may support the hypothesis of microbubble generation in the CVVHD circuit and its transpulmonary translocation toward the intracranial circulation. Importantly, the impact of gaseous and solid CME generated during CVVHD on brain integrity of critically ill patients currently remains unknown and is highly debated.

Laparoscopic hepatectomy carries a high risk of gas embolism due to the extensive hepatic transection plane and large hepatic vena cava. Here, we compared the influence of inhaled and intravenous anesthetics on gas embolism during laparoscopic hepatectomy. Fifty patients undergoing laparoscopic hepatectomy were divided into two groups to receive sevoflurane anesthesia (group S, n = 25) or intravenous propofol anesthesia (group p, n = 25). During the operation, gas emboli were detected by transesophageal echocardiography and graded according to their size. Venous CO2 emboli were detected in all patients, and the embolism grades did not differ between the two groups. However, the mean embolism episode duration was longer in group S than group P (51.24±23.59 vs. 34.00±17.13 sec, p < 0.05). At the point of the most severe gas embolism, the PTCO2 was higher in group S than group p (44.00±4.47 vs. 41.36±2.77 mmHg, p < 0.05), while the PO2/FiO2 (450.52±54.08 vs. 503.80±63.18, p < 0.05) and pH values (7.35±0.05 vs. 7.38±0.02, p < 0.05) were lower in group S than group P. Patients with a history of abdominal surgery or liver cirrhosis had higher gas embolism grades. Thus volatile anesthetics may lengthen the duration of embolism episodes and worsen hemodynamics and pulmonary blood gas exchange during surgery.

Introduction: Ambulation during extravehicular activity on Mars may increase the risk of decompression sickness through enhanced bubble formation in the lower body., Hypotheses: walking effort (ambulation) before an exercise-enhanced denitrogenation (prebreathe) protocol at 14.7 psia does not increase the incidence of venous gas emboli (VGE) at 4.3 psia, but does increase incidence if performed after tissues become supersaturated with nitrogen at 4.3 psia., Methods: VGE results from 45 control subjects who performed exercise prebreathe without ambulation before or during a 4-h exposure to 4.3 psia were compared to 21 subjects who performed the same prebreathe but ambulated before and during the hypobaric exposure (Group I) and to 41 subjects who only ambulated before the hypobaric exposure (Group II). Monitoring for VGE in the pulmonary artery was for 4 min at about 12-min intervals using precordial Doppler ultrasound (2.5 mHz). Detected VGE were assigned a categorical grade from I to IV. The detection of Grade III or IV was classified as "high VGE grade.", Results: The incidence of high VGE grade for Group I (57%) was greater than the control (17%) and Group II (15%). The incidence of pain-only decompression sickness was greater for Group I (20%) than the control (0%) and Group II (5%)., Conclusions: High-grade VGE are increased by mild ambulation conducted under a supersaturated state (Group I vs. II); however, no increase was observed with mild ambulation during the saturated state alone (control vs. Group II).Conkin J, Pollock NW, Natoli MJ, Martina SD, Wessell JH III, Gernhardt ML. Venous gas emboli and ambulation at 4.3 psia. Aerosp Med Hum Perform. 2017; 88(4):370-376.

Background: There is an ongoing debate about the sitting position (SP) in neurosurgical patients. The SP provides a number of advantages as well as severe complications such as commonly concerning venous air embolism (VAE). The best monitoring system for the detection of VAE is still controversial., Methods: In this retrospective analysis we compared 208 patients. Transesophageal echocardiography (TEE) or transthoracic Doppler (TTD) were used as monitoring devices to detect VAE; 101 cases were monitored with TEE and 107 with TTD., Results: The overall incidence of VAE was 23% (TTD: 10%; TEE: 37%), but the incidence of clinically relevant VAE (drop in end-tidal carbon dioxide above 3 mmHg) was higher in the TTD group (9 out of 17 VAE, 53%) compared to the TEE group (19 out of 62 VAE, 31%). None of the patients with recorded VAE had clinically significant sequelae., Conclusions: In this small sample we found more VAE events in the TEE group, but the incidence of clinically relevant VAE was rare and comparable to other data. There is no consensus in the definition of clinically relevant VAE.

Background: Posterior cranial fossa surgery is commonly performed under sitting and horizontal position in our institution. Venous air embolism is a potentially serious complication of neurosurgery especially in the sitting position., Objective: We aim to compare the incidence of severe venous air embolism and other complications of both positions., Material and Method: A retrospective analysis of medical record was performed in 192 patients undergoing posterior cranial fossa craniotomy from January 2010 to December 2013. Data collected from the records included demographic profile, patient position, hemodynamic changes, venous air embolism (VAE), blood loss/transfusion, duration of surgery, postoperative complications, duration of ICU stay, and postoperative discharge status. The definition of severe air embolism was identified as suspected VAE with decreased systolic blood pressure greater than 20%., Results: There were 92 patients in sitting position (SP) group and 100 patients in horizontal position (HP) group. The incidence of severe venous air embolism was signficantly higher in SP group compared with HP group (41.3% vs. 11.0%, p<0. 001). SP group had more complications than HP group in both central nervous system (71% vs. 34.0%, p = 0.001), and cardiovascular system (17% vs. 6%, p = 0.001). Although postoperative ventilator time in SP group was less than HP group (1.24 vs. 1.60 days, p = 0.029), ICU and hospital stay were not different in either group., Conclusion: The incidence of severe venous air embolism detected by end tidal CO₂ was significantly higher in SP group. However, 11% of HP group were suspected of severe air embolism.

Gaseous microemboli (GME) are known to be delivered to the arterial circulation of patients during cardiopulmonary bypass (CPB). An increased number of GME delivered during adult CPB has been associated with brain injury and postoperative cognitive dysfunction. The GME load in children exposed to CPB and its consequences are not well characterized. We sought to establish a baseline of arterial limb emboli counts during the conduct of CPB for our population of patients requiring surgery for congenital heart disease. We used the emboli detection and counting (EDAC) device to measure GME activity in 103 consecutive patients for which an EDAC machine was available. Emboli counts for GME <40 μ and >40 μ were quantified and indexed to CPB time (minutes) and body surface area (BSA) to account for the variation in patient size and CPB times. Patients of all sizes had a similar embolic burden when indexed to bypass time and BSA. Furthermore, patients of all sizes saw a three-fold increase in the <40 μ embolic burden and a five-fold increase in the >40 μ embolic burden when regular air was noted in the venous line. The use of kinetic venous-assisted drainage did not significantly increase arterial limb GME. Efforts for early identification and mitigation of venous line air are warranted to minimize GME transmission to congenital cardiac surgery patients during CPB.

Placing patients who are undergoing neurosurgical procedures to the cervical spine in the sitting position offers significant advantages. These must be counterbalanced against the risk of venous and paradoxical air embolism. This study addresses the role and safety of the sitting position for instrumented cervical surgery. Twenty-five consecutive patients who underwent instrumented cervical surgery in the sitting position were recruited via retrospective analysis. Complications arising from the surgical procedure - specifically venous air embolism - were recorded, as well as pre- and post-operative haemoglobin levels. The incidence of venous air embolism was 0% (97.5% one-sided confidence interval: 0-13.7%). However, five other complications occurred (incidence rate of 20% with a 95% confidence interval of 6.8-40.7%). With appropriate precautions, screening and specific indications, the sitting position can be safely used in more complex instrumented cervical surgery., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Purpose: To determine the impact of the introduction of aerostatic sheaths on air embolism (AE) events during tunneled dialysis catheter (TDC) insertion and to characterize such events occurring during over-the-wire exchange (OTWE)., Materials and Methods: Between July 2001 and April 2013, 5,789 TDCs were placed, including 3,963 de novo placements, 1,811 OTWEs, and 15 tract recanalizations. There were 15 AE events reported, and the medical records of these patients were reviewed. The effect of aerostatic sheaths, introduced in July 2005, was compared with the period before their introduction; the same TDC design was used throughout., Results: Of the 15 AE events, 10 occurred during de novo placement (10 of 3,963 placement; 0.25%), 4 occurred during OTWE (4 of 1,811 placements; 0.22%), and 1 occurred during tract recanalization. With regard to aerostatic sheaths in de novo TDC placement, 4 of 1,174 (0.34%) AE events occurred before aerostatic sheath introduction, and 6 of 2,789 (0.22%) AE events occurred after aerostatic sheath introduction. These rates did not differ statistically (P = .5)., Conclusions: Use of aerostatic sheaths trended toward reducing AE events during de novo TDC placement. This trend was not statistically significant, probably owing to the rarity of AE despite the large sample size. Air embolism occurs during OTWE at a rate similar to de novo placement with aerostatic sheaths as well as during tract recanalization., (Copyright © 2015 SIR. Published by Elsevier Inc. All rights reserved.)

Background: Scuba diving injuries vary greatly in severity and prognosis. While decompression sickness (DCS) and arterial gas embolism can be tracked easily, other forms of diving injury remain unaccounted for., Purpose: The purpose of this paper is to assess rates of overall self-reported scuba-diving-related injuries, self-reported DCS-like symptoms, and treated DCS and their association with diver certification level, diving experience and demographic factors., Methods: We analyzed self-reported data from a Divers Alert Network membership health survey conducted during the summer of 2011. Poisson regression models with scaled deviance were used to model the relative rates of reported injuries. Models were adjusted for sex, age, body mass index (BMI) and average annual dives, based on the bias-variance tradeoff., Results: The overall rate of diving-related injury was 3.02 per 100 dives, self-reported DCS symptoms was 1.55 per 1,000 dives and treated DCS was 5.72 per 100,000 dives. Diving-related injury and self-reported DCS symptom rates decreased for higher diver certification levels, increasing age, increasing number of average annual dives and for men; they increased for increasing BMI., Conclusions: Diving injury rates may be higher than previously thought, indicating a greater burden on the diving community. Self-reported DCS-like symptoms are a small fraction of all dive-related injuries and those receiving treatment for DCS are an even smaller fraction. The small number of divers seeking treatment may suggest the mild nature and a tendency towards natural resolution for most injuries.

Objective: To analyze the actual risk for patients with a patent foramen ovale (PFO) to experience a clinically relevant venous air embolism (VAE) during surgery performed in the semisitting position., Methods: All procedures were performed between January 2008 and December 2009, under general anesthesia and in the semisitting position. Transesophageal echocardiography (TEE) and capnometry were used intraoperatively to monitor for air bubbles in the venous system., Results: Of 200 consecutive patients who all were operated on in the semisitting position, 52 patients (26%) had a diagnosis of PFO. Rates of VAE in patients were graded as follows: grade 0 (no air bubbles visible, no air embolism), 23 patients (44.2%); grade I (air bubbles on TEE), 22 patients (42.3%); grade II (air bubbles on TEE with decrease of end-tidal carbon dioxide [ETCO2] ≤ 3 mm Hg), 2 patients (3.8%); grade III, air bubbles on TEE with decrease of ETCO2 >3 mm Hg, 4 patients (7.7%); grade IV, air bubbles on TEE with decrease of ETCO2 >3 mm Hg and decrease of mean arterial pressure ≥ 20% or increase of heart rate ≥ 40% (or both), 1 patient (1.9%); and grade V, VAE causing arrhythmia with hemodynamic instability requiring cardiopulmonary resuscitation, 0 patients (0%). There were no deaths in this series, and no new or unexplained, mild or severe neurologic deficits were caused by a VAE., Conclusions: Under standardized anesthesia and neurosurgical protocols, patients with a PFO can be operated on safely in the semisitting position., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Introduction: Venous air embolism (VAE) is the entry of air or other medical gases into the central venous system, producing an air embolism to the right heart or pulmonary artery. VAE is a largely iatrogenic complication with potentially devastating sequelae that can occur in a variety of surgical procedures., Method: Within orthopaedics, VAE has been associated with both open and arthroscopic surgeries with the patient in a variety of positions (ie, prone, supine, sitting). These articles, as well as reports of VAE in other surgical settings outside of orthopaedics, are examined., Conclusion: Diagnosis of VAE requires a high index of suspicion, as clinical presentation ranges from completely asymptomatic to fatal cardiopulmonary collapse. The vigilant surgeon should carefully watch for air entry at the operative site and the astute anesthesiologist must closely monitor end-tidal CO2 (ETCO2). Prevention of VAE is of paramount importance, as management is largely supportive and aimed at inhibiting further air ingress., (Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Objective: Cardiopulmonary bypass (CPB) is a lifesaving practice in cardiac surgery, but its use frequently is associated with cerebral injury and neurocognitive dysfunctions. Despite the involvement of numerous factors, microembolism occurring during CPB seems to be one of the main mechanisms leading to such alterations. The aim of the present study was to characterize the occurrence of cerebral microembolism with reference to microembolic amount, nature, and distribution in different combinations of cardiac procedures and CPB on the microembolic load., Design: A retrospective observational clinical study., Setting: A single-center regional hospital., Participants: Fifty-five patients undergoing elective cardiac surgery with CPB., Interventions: Bilateral detection of the patients' middle cerebral arteries using a multifrequency transcranial Doppler., Measurements and Main Results: Patients were divided into 3 groups depending on the CPB circuit used (open, open with vacuum, or closed). There was a significant difference between the number of solid and gaseous microemboli (p<0.001), with the solid lower than the gaseous ones. The number of solid microemboli was affected by group (p< 0.05), CPB phase (p<0.001), and laterality (p<0.01). The number of gaseous microemboli was affected only by group (p<0.05) and CPB phase (p<0.001). Generally, the length of CPB phase did not affect the number of microemboli., Conclusions: Surgical procedures combined with CPB circuits, but not the CPB phase length, affected the occurrence, nature, and laterality of microemboli., (Copyright © 2013 Elsevier Inc. All rights reserved.)