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Background: Intravenous (IV) infusions of volatile anesthetics in lipid emulsion may increase blood lipid concentration, potentially altering the anesthetic agent's blood solubility and blood-gas partition coefficient (BGPC). We examined the influence of a low-lipid concentration 20% sevoflurane emulsion on BGPC, and the anesthetic potency of this emulsion using dogs., Methods: We compared BGPC and anesthetic characteristics in 6 dogs between the IV anesthesia of emulsion and the sevoflurane inhalation anesthesia in a randomized crossover substudy. Minimum alveolar concentrations (MACs) were determined by tail-clamp stimulation by using the up-and-down method. Blood sevoflurane concentration and partial pressure were measured by gas chromatography; end-tidal sevoflurane concentration was measured using a gas monitor. The primary outcome was BGPC at the end of IV anesthesia and inhalation anesthesia. Secondary outcomes were time to loss/recovery of palpebral reflex, finish intubation and awakening, MAC, blood concentration/partial pressure at MAC and awakening, correlation between blood partial pressure and gas monitor, and the safety of emulsions., Results: BGPC showed no difference between IV and inhaled anesthesia (0.859 [0.850-0.887] vs 0.813 [0.791-0.901]; P = .313). Induction and emergence from anesthesia were more rapid in IV anesthesia of emulsion than inhalation anesthesia. MAC of emulsion (1.33% [1.11-1.45]) was lower than that of inhalation (2.40% [2.33-2.48]; P = .031), although there was no significant difference in blood concentration. End-tidal sevoflurane concentration could be estimated using gas monitor during IV anesthesia of emulsion. No major complications were observed., Conclusions: IV anesthesia with emulsion did not increase the BGCP significantly compared to inhalation anesthesia. It was suggested that the anesthetic potency of this emulsion may be equal to or more than that of inhalation., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2020 International Anesthesia Research Society.)

Disseminated carcinomatosis of the bone marrow (DCBM) is characterized by diffuse metastasis to bone marrow and sudden mortality. To the best of our knowledge, no studies to date have reported progression of oral squamous cell carcinoma to DCBM. Herein, we report a case of squamous cell carcinoma in the maxillary gingiva suspected of progressing to DCBM. A 64-year-old woman presented with white lesions on the left maxillary gingiva. The lesions were diagnosed as squamous cell carcinoma (T2, N0, M0), and partial maxillectomy performed. Two years and 5 months after surgery, metastasis was noted in the left cervical lymph node and left radical neck dissection carried out. The subsequent diagnosis was right cervical lymph node metastasis and multiple bone metastases. The patient also presented with thrombocytopenia, anemia, and elevated levels of alkaline phosphatase, probably due to metastatic bone disease. Although various antitumor therapies were administered, the patient died 6 months after diagnosis of multiple bone metastases.

In the present study, we evaluated activated areas of the cerebral cortex with regard to the mirror neuron system during swallowing. To identify the activated areas, we used magnetoencephalography. Subjects were ten consenting volunteers. Swallowing-related stimuli comprised an animated image of the left profile of a person swallowing water with laryngeal elevation as a visual swallowing trigger stimulus and a swallowing sound as an auditory swallowing trigger stimulus. As control stimuli, a still frame image of the left profile without an additional trigger was shown, and an artificial sound as a false auditory trigger was provided. Triggers were presented at 3,000 ms after the start of image presentation. The stimuli were combined and presented and the areas activated were identified for each stimulus. With animation and still-frame stimuli, the visual association area (Brodmann area (BA) 18) was activated at the start of image presentation, while with the swallowing sound and artificial sound stimuli, the auditory areas BA 41 and BA 42 were activated at the time of trigger presentation. However, with animation stimuli (animation stimulus, animation + swallowing sound stimuli, and animation + artificial sound stimuli), activation in BA 6 and BA 40, corresponding to mirror neurons, was observed between 620 and 720 ms before the trigger. Besides, there were also significant differences in latency time and peak intensity between animation stimulus and animation + swallowing sound stimuli. Our results suggest that mirror neurons are activated by swallowing-related visual and auditory stimuli.

With the founding of its Oral Cancer Center at the Ichikawa General Hospital, Tokyo Dental College established a support system for patients and family members that not only provides surgery and other conventional cancer-oriented treatments, but also palliative care, nutritional support, rehabilitation, and discharge support. With this in mind, the present study sought to examine the nature of support for oral cancer patients with postoperative eating and swallowing disorders by investigating these disorders and identifying their risk factors. The study population comprised 75 surviving oral cancer patients (46 men and 29 women) discharged from the Tokyo Dental College Oral Cancer Center following treatment over a 2-year period from April 2009 to March 2011. Risk factors affecting eating and swallowing function were identified by statistical analysis. Mean age of the patients was 67.3±13.7 years. Fifteen patients had stage I cancer, while 25 had stage II, 13 had stage III, and 22 had stage IV. The feeding route at the time of discharge was oral feeding in 74 patients and a combination of oral and gastrostomy tube feeding in 1 patient. The Tokyo Dental College Ichikawa General Hospital has standardized the expert evaluation and rehabilitation of oral cancer patients with eating and swallowing disorders by establishing a multidisciplinary support system from the preoperative stage onwards. In this context, the results of our analysis of factors influencing the ability of oral cancer patients to orally ingest food after treatment suggest that preoperative cancer stage classification, neck dissection, and tracheotomy are all influential factors. Patients affected by these factors require further multidisciplinary treatment, which in turn necessitates more extensive coordination with other medical professionals and community health care providers.

We analyze a duopolistic health care market in which a rural public hospital competes against an urban public hospital on medical quality, by using a Hotelling-type spatial competition model extended into a two-region model. We show that the rural public hospital provides excess quality for each unit of medical service as compared to the first-best quality, and the profits of the rural public hospital are lower than those of the urban public hospital because the provision of excess quality requires larger expenditure. In addition, we investigate the impact of the partial (or full) privatization of local public hospitals.

Background: Advancing a tracheal tube into the bronchus produces unilateral breath sounds. We created a Visual Stethoscope that allows real-time fast Fourier transformation of the sound signal and 3-dimensional (frequency-amplitude-time) color rendering of the results on a personal computer with simultaneous processing of 2 individual sound signals. The aim of this study was to evaluate whether the Visual Stethoscope can detect bronchial intubation in comparison with auscultation., Methods: After induction of general anesthesia, the trachea was intubated with a tracheal tube. The distance from the incisors to the carina was measured using a fiberoptic bronchoscope. While the anesthesiologist advanced the tracheal tube from the trachea to the bronchus, another anesthesiologist auscultated breath sounds to detect changes of the breath sounds and/or disappearance of bilateral breath sounds for every 1 cm that the tracheal tube was advanced. Two precordial stethoscopes placed at the left and right sides of the chest were used to record breath sounds simultaneously. Subsequently, at a later date, we randomly entered the recorded breath sounds into the Visual Stethoscope. The same anesthesiologist observed the visualized breath sounds on the personal computer screen processed by the Visual Stethoscope to examine changes of breath sounds and/or disappearance of bilateral breath sound. We compared the decision made based on auscultation with that made based on the results of the visualized breath sounds using the Visual Stethoscope., Results: Thirty patients were enrolled in the study. When irregular breath sounds were auscultated, the tip of the tracheal tube was located at 0.6 +/- 1.2 cm on the bronchial side of the carina. Using the Visual Stethoscope, when there were any changes of the shape of the visualized breath sound, the tube was located at 0.4 +/- 0.8 cm on the tracheal side of the carina (P < 0.01). When unilateral breath sounds were auscultated, the tube was located at 2.6 +/- 1.2 cm on the bronchial side of the carina. The tube was also located at 2.3 +/- 1.0 cm on the bronchial side of the carina when a unilateral shape of visualized breath sounds was obtained using the Visual Stethoscope (not significant)., Conclusions: During advancement of the tracheal tube, alterations of the shape of the visualized breath sounds using the Visual Stethoscope appeared before the changes of the breath sounds were detected by auscultation. Bilateral breath sounds disappeared when the tip of the tracheal tube was advanced beyond the carina in both groups.

Objective: The purpose of this study was to investigate the reliability of cardiac output (CO) measured by a new ultrasound dilution method (COud) in comparison with CO by pulmonary artery thermodilution (COtd) in adult patients undergoing surgery., Design: A prospective study., Setting: A university hospital, single institutional., Participants: Twenty-nine adult patients undergoing abdominal surgery., Measurements and Main Results: After approval of the institutional ethics review board, 29 adult patients were evaluated. After induction, radial and pulmonary artery catheters were inserted. A disposable extracorporeal AV loop was connected between existing arterial and central venous catheters. Reusable ultrasound sensors that measure changes in blood ultrasound velocity after dilution by isotonic saline were clamped onto the arterial and venous limbs of the loop. Ultrasound dilution (UD) measurements (COstatus; Transonic Systems, Inc, Ithaca, NY) were obtained by injecting 30 mL of body-temperature isotonic saline into the venous limb of the AV loop. An average of 3 COud and 5 COtd was obtained for comparison. Bland-Altman plot and correlation analysis were used for statistical comparison. A total of 142 comparison measurements were obtained. The correlation coefficient between the 2 techniques was r = 0.91. Bland-Altman analysis did not produce any significant bias (bias = 0.02, standard deviation = 0.56). The percentage error of these data was 23.53%., Conclusions: COud measurements agreed well with COtd. The results of this study indicated that COud might be interchangeable with conventional COtd in perioperative adult patients.

We investigate a health care market with uncertainty in a mixed duopoly, where a partially privatized public hospital competes against a private hospital in terms of quality choice. We use a simple Hotelling-type spatial competition model by incorporating mean-variance analysis and the framework of partial privatization. We show how the variance in the quality perceived by patients affects the true quality of medical care provided by hospitals. In addition, we show that a case exists in which the quality of the partially privatized hospital becomes higher than that of the private hospital when the patient's preference for quality is relatively high.

Background: Although hemorrhagic shock decreases the minimum alveolar concentration (MAC) of inhaled anesthetics, it minimally alters the electroencephalographic (EEG) effect. Hemorrhagic shock also induces the release of endorphins, which are naturally occurring opioids. We tested whether the release of such opioids might explain the decrease in MAC., Methods: Using the dew claw-clamp technique in 11 swine, we determined the isoflurane MAC before hemorrhage, after removal of 30% of the estimated blood volume (21 mL/kg of blood over 30 min), after fluid resuscitation using a volume of hydroxyethylstarch equivalent to the blood withdrawn, and after IV administration of 0.1 mg/kg of the mu-opioid antagonist naloxone., Results: Hemorrhagic shock decreased the isoflurane MAC from 2.05% +/- 0.28% to 1.50% +/- 0.51% (P = 0.0007). Fluid resuscitation did not reverse MAC (1.59% +/- 0.53%), but additional administration of naloxone restored it to control levels (1.96% +/- 0.26%). The MAC values decreased depending on the severity of the shock, but the alterations in hemodynamic variables and metabolic changes accompanying fluid resuscitation or naloxone administration did not explain the changes in MAC., Conclusions: Consistent with previous reports, we found that hemorrhagic shock decreases MAC. In addition, we found that naloxone administration reversed the effect on MAC, and we propose that activation of the endogenous opioid system accounts for the decrease in MAC during hemorrhagic shock. Such an activation would not be expected to materially alter the EEG, an expectation consistent with our previous finding that hemorrhagic shock minimally alters the EEG.

Background: Epidural anaesthesia is an efficient method of providing both regional anaesthesia and post-operative pain relief. Detection of the epidural space is critical, but it is difficult to predict the depth of the epidural space. Published results are inconsistent. We retrospectively investigated the differences in the depth of the epidural space depending on the puncture site, approach type and physical findings of patients., Methods: All surgical patients from 1994 to 2005 were included in the study and 4964 cases were analysed. The recorded distance from the needle tip to the skin surface was defined as the depth of the epidural. The differences in the depth were compared according to the puncture site, level and approach. We then searched for the factors determining the depth using multivariate regression analysis., Results: The depth in upper thoracic sites (T1/2-T9/10) was 5.0 (1.0) cm [mean (SD), n= 465] via the midline approach and 5.2 (1.0) cm (n= 1226) via the paramedian approach. For lumbar sites, the depth was 4.1 (0.9) cm (n= 1835) via the midline approach and 4.6 (1.0) cm (n= 298) via the paramedian approach. In the multivariate regression analysis, patient age, body weight and more cephalad puncture were significantly and positively correlated with the depth at thoracic sites., Conclusions: The epidural space was deeper at upper thoracic sites than lower thoracic or lumbar sites. The depth with the paramedian approach was greater than with the midline approach at both sites. Patient age and weight were positive factors for depth.

Background: beta-Adrenergic blocking agents may interact with anaesthetics, and several studies suggest that beta-blockers attenuate electroencephalographic responses during general anaesthesia. We have investigated the influence of landiolol, an ultra-short-acting beta 1-adrenoceptor antagonist, on the electroencephalographic effect of isoflurane in pigs., Methods: Ten swine were anaesthetized through inhalation of 2% isoflurane. The inhalational concentration was then decreased to 0.5% and maintained for 25 min, before being returned to 2% and maintained for a further 25 min (control period). After control measurements, infusion of landiolol (at 0.125 mg kg(-1) min(-1) for 1 min, and then at 0.04 mg kg(-1) min(-1)) was started. After a 20 min stabilization period, the inhalational concentration was varied as in the control period (40 gamma landiolol). Finally, infusion of landiolol was increased from 0.04 to 0.2 mg kg(-1) min(-1), and after a 20 min stabilization period, the inhalational concentration was again varied as in the control period (200 gamma landiolol). End-tidal isoflurane concentrations and spectral edge frequencies were recorded throughout the study. Analysis of the pharmacodynamics was performed using a sigmoidal inhibitory maximal effect model for spectral edge frequency vs effect-site concentration., Results: There were no significant differences in the effect of isoflurane among the conditions used. Landiolol did not shift the concentration-effect relationship [the effect-site concentration that produced 50% of the maximal effect was 1.35 (0.17)% under control conditions, 1.30 (0.12)% at 40 gamma landiolol, and 1.38 (0.30)% at 200 gamma landiolol]., Conclusion: Landiolol does not alter the electroencephalographic effect of isoflurane.

Background: The authors have previously reported that hemorrhage does not alter the electroencephalographic effect of isoflurane under conditions of compensated hemorrhagic shock. Here, they have investigated the influence of decompensated hemorrhagic shock and subsequent fluid resuscitation on the electroencephalographic effect of isoflurane., Methods: Twelve swine were anesthetized through inhalation of 2% isoflurane. The inhalational concentration was then decreased to 0.5% and maintained for 25 min, before being returned to 2% and maintained for 25 min (control period). Hemorrhagic shock was then induced by removing 28 ml/kg blood over 30 min. After a 30-min stabilization period, the inhalational concentration was varied as in the control period. Finally, fluid infusion was performed over 30 min using a volume of hydroxyethyl starch equivalent to the blood withdrawn. After a 30-min stabilization period, the inhalational concentration was again varied as in the control period. End-tidal isoflurane concentrations and spectral edge frequency were recorded throughout the study. The pharmacodynamics were characterized using a sigmoidal inhibitory maximal effect model for spectral edge frequency versus effect site concentration., Results: Decompensated hemorrhagic shock slightly but significantly shifted the concentration-effect relation to the left, demonstrating a 1.12-fold decrease in the effect site concentration required to achieve 50% of the maximal effect in the spectral edge frequency. Fluid resuscitation reversed the onset of isoflurane, which was delayed by hemorrhage, but did not reverse the increase in end-organ sensitivity., Conclusions: Although decompensated hemorrhagic shock altered the electroencephalographic effect of isoflurane regardless of fluid resuscitation, the change seemed to be minimal, in contrast to several intravenous anesthetics.

Background: Hypovolemia alters the effect of several intravenous anesthetics by influencing pharmacokinetics and end-organ sensitivity. The authors investigated the influence of hypovolemia on the effect of an inhalation anesthetic, isoflurane, in a swine hemorrhage model., Methods: Eleven swine were studied. After animal preparation with inhalation of 2% isoflurane anesthesia, the inhalation concentration was decreased to 0.5% and maintained at this level for 25 min before being returned to 2% (control). After 25 min, hypovolemia was induced by removing 14 ml/kg of the initial blood volume via an arterial catheter. After a 25-min stabilization period, the inhalation concentration was decreased to 0.5%, maintained at this level for 25 min, and then returned to 2% (20% bleeding). After another 25 min, a further 7 ml/kg blood was collected, and the inhalation concentration was altered as before (30% bleeding). End-tidal isoflurane concentrations and an electroencephalogram were recorded throughout the study. Spectral edge frequency was used as a measure of the isoflurane effect, and pharmacodynamics were characterized using a sigmoidal inhibitory maximal effect model for the spectral edge frequency versus end-tidal concentration., Results: There was no significant difference in the effect of isoflurane among the conditions used. Hypovolemia did not shift the concentration-effect relation (the effect site concentration that produced 50% of the maximal effect was 1.2 +/- 0.2% under control conditions, 1.2 +/- 0.2% with 20% bleeding, and 1.1 +/- 0.2% with 30% bleeding)., Conclusions: Hypovolemia does not alter the electroencephalographic effect of isoflurane, in contrast to several intravenous anesthetics.

The concentrations of nitrous oxide, sevoflurane and oxygen in the circle system of a closed-circuit anaesthesia machine, the PhysioFlex, were measured in seven patients. During anaesthesia, the settings for each gas were changed and their concentrations recorded. At the induction of anaesthesia, it took 80-510s (median 190s) for the end-tidal sevoflurane concentration to reach 2.0%, and 920-2640s (median 1500s) for the oxygen in the breathing circuit to reach 30%. At this time, the nitrous oxide concentration was 60+/-3% (mean+/-SD). During anaesthesia, it took 90-480s (median 140s) for the end-tidal sevoflurane concentration setting to decrease from 3.0 to 1.0%, and 90-400s (median 110s) to return from 1.0 to 3.0%. When the inspired oxygen was increased from 30 to 50%, circuit concentrations reached equilibrium in 40-60s (median 40s), and when decreased from 50% back to 30%, equilibrium took 310-470s (median 450s). During recovery from anaesthesia, inspiratory sevoflurane concentration took 40-70s (median 50s) to decrease to 0.2%. The PhysioFlex provided adequate control of sevoflurane and oxygen concentrations, but not of increasing nitrous oxide concentrations.

Sevoflurane anaesthesia was conducted using a totally closed circuit PhysioFlex anaesthesia machine (PhysioFlex group) or with a standard Modulus CD anaesthesia machine (Modulus group) (n = 8 in each group). The PhysioFlex was used under closed system conditions and the Modulus was used under low-flow system conditions (flow rate 1 litre min-1). Concentrations of sevoflurane degradation products and the temperature of soda lime were compared. Degradation products in the circuit were measured hourly, and the temperature of soda lime was monitored. The only degradation product detected was CF2 = C(CF3)-O-CH2F (compound A). Maximum concentrations of compound A were significantly lower (median 8.5 (range 5.4-15.9) ppm) in the PhysioFlex than in the Modulus group (21.2 (16.5-27.4) ppm) (P < 0.05). The maximum temperature of soda lime was also significantly lower in the PhysioFlex group (35.3 (32.1-36.3) degrees C vs 44.6 (43.0-47.1) degrees C, respectively) (P < 0.05). Hourly compound A concentrations were lower in the PhysioFlex group than in the Modulus group. End-tidal sevoflurane concentrations during measurement of degradation products were not different between groups. Therefore, use of the totally closed PhysioFlex system may significantly reduce compound A concentrations compared with low-flow anaesthesia using a standard anaesthesia machine.

Objective: To develop an ergonomically designed computerized recordkeeping tool for anesthesiologists that allows the clinician to maintain visual contact with the patient while performing recordkeeping., Methods: To simplify the human interface software, we developed two general use software components. All purpose menu type 1 (APM1) was used for entering events using a tree structured menu. APM1 was designed to adapt to the limits of human memory, by using Miller's rule of 7 to guide the input process. APM1 can be considered to be a three-dimensional table list consisting of 7 vertical and 7 horizontal choices, which has further 5 tree-structured divergences. APM1 is also completely configurable by the user. All purpose menu 2 (APM2) was used to implement the system-initiated human interface where the system will prompt the user by voice for each entry. When users touch a key on APM1 and APM2, the system was designed to respond with a voice prompt. A touch-screen was also utilized and designed to fit the anesthesia machine. The screen is equipped with a small speaker for voice response and a microphone for voice recognition. The positions of the screen are adjustable supported by a long flexible limb (85 cm)., Results: After improving the design, systems were assembled for 10 operating rooms. Of the multiple features of the VOCAAR user interface, the following were well accepted by users and employed daily: touch-screen input, and voice response. The noncompulsory use rate was 87% during the initial 2 weeks, increased to 94% after 2 weeks and 100% after two months. The mean sound emission by voice response (n = 10, mean +/- SD) was 8.2 +/- 2.3 dB at the main anesthetist site (35 cm from the speaker mounted on the touch-screen), 2.2 +/- 1.3 dB at the staff site (1.5 m from the touch-screen), which was only audible for anesthesiologist but for surgeon., Discussion: An EARK system was designed to allow the user to maintain visual contact with the patient while performing recordkeeping tasks. The combination of a mobile touch screen and voice response/recognition facilitated the design goals of the system. Although the system has enjoyed universal clinical acceptance, the voice functions remain too limited to satisfy the needs of a completely handsfree user interface. Enhancements to voice recognition technology will offer the potential for improved functionality. Additional research is also needed to better define the relationship between vigilance and visual contact with the patient.

Objective: In order to predict the partial pressure of volatile anesthetics in brain tissue, we developed a pharmacokinetic simulation model suitable for real time application. The accuracy of this model was examined by comparing the predicted values against measured values for blood sampled from the internal jugular vein, which was used as a measure of the partial pressure in the brain., Methods: Our model consists of six compartments: alveoli, arterial blood, a group of vessel-rich organs (VRG), muscle, fat, and venous blood. A volatile anesthetic, sevoflurane partial pressure in each compartment were calculated using the parameters of volume, blood flow, and solubility for each tissue as reported in previous studies. Simulated sevoflurane partial pressures in VRG were considered to reflect those in the brain. We studied 11 patients undergoing elective abdominal surgery or mastectomy. Sevoflurane was maintained at a concentration of 3% (by vaporizer setting) for 25 min. Sampling points were at 0 min (before sevoflurane administration) and 1, 2, 4, 9, 16, and 25 min after the start of inhalation. We measured the sevoflurane partial pressure in inspiratory gas (PI(S)), in end-expiratory gas (PET(S)), in arterial blood (Pa(S)), and in internal jugular vein blood (Pj(S)). These values were compared against those for the simulated brain (PB(S)sim)., Results: The sevoflurane partial pressures increased, in order from least rapid to most rapid, as follows: Pj(S), PB(S)sim, Pa(S), PET(S), and PI(S). The differences between Pj(S) and PB(S)sim were significantly smaller than those between Pj(S) and PET(S) at all sampling points. PB(S)sim did not differ significantly from Pj(S) at any sampling points after 4 min of inhalation, while PET(S) differed significantly from Pj(S) at all sampling points., Conclusion: We conclude that our model is clinically useful for predicting sevoflurane partial pressure in the brain, assuming that Pj(S) reflects the sevoflurane partial pressure in the brain.

Background: The propofol awakening concentration can vary. However, the effect site awakening propofol concentration will be a fixed value. The purpose of this study was to determine the awakening propofol concentrations obtained from infusion Schede using abrupt discontinuation of propofol (half-maximal effective concentration [EC50]) or a descending decrease in concentration to allow blood-effect site equilibration (EC50eq)., Methods: Patients undergoing short-term (group 1) and long-term (group 2) elective surgery were anesthetized with computer-assisted continuous infusion of propofol and fentanyl, with both groups receiving the same propofol (3 microg/ml) and fentanyl (1 ng/ml) concentrations 20-30 min before the end of surgery until the end. Then both groups were further divided into two subgroups: subgroup A abrupt discontinuation, and subgroup B descending concentrations of propofol (15-min duration per concentration). In the A subgroups, the response to verbal command was evaluated every 30 s. In the B subgroups, the blood propofol concentrations just permitting and just preventing response to command were averaged individually. The EC50 and EC50eq values were determined by probit analysis., Results: The EC50 of group 1A was 1 microg/ml, which was significantly less than the 1.6 microg/ml of group 2A (P < 0.05). The awakening time of group 1A was 5.2 +/- 1.8 min, which was significantly shorter than the 9.3 +/- 3.5 min of group 2A (means +/- SD). The EC50eq of both groups 1B and 2B was 2.2 microg/ml., Conclusions: The EC50eq was independent of propofol infusion length, compared with the EC50. Thus the potential for hysteresis during emergence from propofol anesthesia was confirmed.

Tension pneumoperitoneum may force gas into a small injured vessel if the opening is kept patent by surrounding tissues. However, the amount of carbon dioxide (CO2) that penetrates through injured or noninjured peritoneum has not been systematically determined. In 25 patients undergoing elective laparoscopic ultrasonography and cholecystectomy, CO2 output (VCO2) and O2 uptake (VO2) were measured at baseline and during anesthesia, pneumoperitoneum, laparoscopic surgical procedure (Surgery), and after hemostasis of the surgical field (Postsurgery). Before anesthesia, VCO2/BSA and VO2/BSA were 97.7 +/- 11.3 and 116.0 +/- 10.0 ml x min(-1) x m(-2), respectively. During anesthesia, they fell to 72.3 +/- 6.0 and 89.8 +/- 7.6 ml x min(-1) x m(-2), respectively (p < 0.05). VCO2/BSA increased to 96.0 +/- 11.1 at pneumoperitoneum (p < 0.05) and increased further to 126.1 +/- 11.0 ml x min(-1) x m(-2) at Surgery. It fell to 111.7 +/- 10.9 ml x min(-1) x m(-2) Postsurgery. VO2/BSA remained unchanged during pneumoperitoneum. Minute volume increased from 2.24 +/- 0.20 in anesthesia to 2.89 +/- 0.25, 4.01 +/- 0.32, and 3.46 +/- 0.28 L x min(-1) x m(-2) during pneumoperitoneum, Surgery, and Postsurgery, respectively, to maintain PaCO2. We conclude that the amount of CO2 absorbed following pneumoperitoneum prior to surgery is lower than that during Surgery or Postsurgery. The amount of CO2 absorbed through the surgical field was 2.3 times higher than that through the nonsurgical field while that from the peritoneum after hemostasis of surgical field was 1.6 times higher.

Long-time oral intake of magnesium-silicate-containing drugs is thought to be a causative factor inducing silicate urolithiasis. Besides, magnesium seems to play an anti-urolithogenic part in the formation of calcium oxalate stones. We report a recurrent calcium oxalate former who had been treated with magnesium aluminometasilicate antacid for gastric ulcer for approximately 17 years. One of the fragments found during extracorporeal shock wave lithotripsy was identified as 100% silicate. Deposition of silica was also found on other fragments. A large dose of magnesium (given in a part of the drug) might have little influence on the formation of calcium oxalate.

Critically ill or anesthetized patients commonly receive pump-driven intravenous infusions of potent, fast-acting, short half-life medications for managing hemodynamics. Stepwise dosing, e.g. over 3-5 min, adjusts physiologic responses. Flow rates range from < 0.1 to > 30 ml/h, depending on pump type (large volume, syringe) and drug concentration. Most drugs are formulated in aqueous solutions. Hydrophobic drugs are formulated as lipid emulsions. Do the physical and chemical properties of emulsions impact delivery compared to aqueous solutions? Does stepwise dose titration by the pump correlate with predicted plasma concentrations? Precise, gravimetric, flow rate measurement compared delivery of a 20% lipid emulsion (LE) and 0.9% saline (NS) using different pump types and flow rates. We measured stepwise delivery and then computed predicted plasma concentrations following stepwise dose titration. We measured the pharmacokinetic coefficient of short-term variation, (PK-CV), to assess pump performance. LE and NS had similar mean flow rates in stepwise rate increments and decrements between 0.5 and 32 ml/h and continuous flows 0.5 and 5 ml/h. Pharmacokinetic computation predictions suggest delayed achievement of intended plasma levels following dose titrations. Syringe pumps exhibited smaller variations in PK-CV than large volume pumps. Pump-driven deliveries of lipid emulsion and aqueous solution behave similarly. At low flow rates we observed large flow rate variability differences between pump types showing they may not be interchangeable. PK-CV analysis provides a quantitative tool to assess infusion pump performance. Drug plasma concentrations may lag behind intent of pump dose titration., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

We developed a miniature mixing chamber, the bymixer, that aids in the measurement of respiratory gas metabolism and inhalation anesthetic uptake. A small fraction of total respiratory gas flow is bypassed from the inspiratory or expiratory limb of the breathing circuit to the bymixer. We tested the relationship between total flow and bypass flow. To analyze the error and response time of the system, we compared the mixed expired carbon dioxide from the bymixer (capacity, 0.3 L, ratio of bypass flow to total flow, 1/4.5) with that from a conventional 2.0-L mixing chamber in 15 volunteers and 12 anesthetized patients during spontaneous or controlled ventilation. Bypass flow correlated well with total flow (r2 = 0.999 to 1.000) when total flow ranged from 0 to 70 L/min and the ratio of bypass flow to total flow ranged from 1/3 to 1/20. The difference between the values of mixed expired carbon dioxide from the two mixing chambers was small, ranging from -0.03 to 0.01 vol% in both of the ventilatory modes. The relative error was within 2.3% of the carbon dioxide values obtained from the conventional chamber. We observed the error at the lowest minute volume (4 L/min). The 90% response time of the bymixer (24.8 seconds) was similar to that of the conventional chamber (19.1 seconds) at a minute volume of 7.5 L/min. For clinical use, we combined a conventional breathing circuit with two bymixers, one for mixing inspired gas and the other for mixing expired gas. We found this device accurate and easy to use.

Introduction: Hemodialysis treatment using standard dialysate bicarbonate concentrations cause transient metabolic alkalosis possibly associated with hemodynamic instability. The aim of this study was to perform a detailed comparison of high and low dialysate bicarbonate in terms of blood pressure, intradialytic hemodynamic parameters, orthostatic blood pressure, and electrolytes., Methods: Fifteen hemodialysis patients were examined in a single-blind, randomized, controlled, crossover study. Participants underwent a 4-h hemodialysis session with dialysate bicarbonate concentration of 30 or 38 mmol/L with 1 week between interventions. Blood pressure was monitored throughout hemodialysis, while cardiac output, total peripheral resistance, stroke volume, and central blood volume were assessed with ultrasound dilution technique (Transonic). Orthostatic blood pressure was measured pre- and post-hemodialysis., Findings: With similar ultrafiltration (UF) volume (2.6 L), systolic blood pressure (SBP) tended to decrease more during high dialysate bicarbonate compared to low dialysate bicarbonate; the mean (95% confidence interval) between treatment differences in SBP were: 8 (-4; 20) mmHg (end of hemodialysis) and 7 (0; 15) mmHg (post-hemodialysis). Stroke volume decreased whereas total peripheral resistance increased significantly more during high dialysate bicarbonate compared to low dialysate bicarbonate with mean between treatment differences: Stroke volume: 12 (1; 23) mL; Total peripheral resistance: -2.9 (-5.3; -0.5) mmHg/(L/min). Cardiac output tended to decrease more with high dialysate bicarbonate compared to low dialysate bicarbonate with mean between treatment difference 0.7 (0.0; 1.4) L/min. High dialysate bicarbonate caused alkalosis, hypocalcemia, and lower plasma potassium, whereas patients remained normocalcemic with normal pH during low dialysate bicarbonate. Orthostatic blood pressure response after dialysis did not differ significantly., Discussion: The use of high dialysate bicarbonate compared to low dialysate bicarbonate was associated with hypocalcemia, alkalosis, and a more pronounced hypokalemia. During hemodialysis with UF, a better preservation of blood pressure, stroke volume, and cardiac output may be achieved with low dialysate bicarbonate compared to high dialysate bicarbonate., (© 2024 The Author(s). Hemodialysis International published by Wiley Periodicals LLC on behalf of International Society for Hemodialysis.)

Background: Residual deep sedation during anesthesia recovery may predict postoperative complications. We examined the incidence and risk factors for deep sedation after general anesthesia., Methods: We retrospectively reviewed health records of adults who underwent procedures with general anesthesia and were admitted to the postanesthesia care unit from May 2018 to December 2020. Patients were dichotomized by Richmond Agitation-Sedation Scale (RASS) score: ≤-4 (deeply sedated/unarousable) or ≥-3 (not deeply sedated). Anesthesia risk factors for deep sedation were assessed with multivariable logistic regression., Results: Of the 56,275 patients included, 2003 had a RASS ≤-4 (35.6 [95% CI, 34.1-37.2] cases per 1000 anesthetics administered). On adjusted analyses, the likelihood of a RASS ≤-4 increased when more soluble halogenated anesthetics were used. Compared with desflurane without propofol, the odds ratio (OR [95% CI]) for a RASS ≤-4 was higher with sevoflurane (1.85 [1.45-2.37]) and isoflurane (4.21 [3.29-5.38]) without propofol. Compared with desflurane without propofol, the odds of a RASS ≤-4 further increased with use of desflurane-propofol (2.61 [1.99-3.42]), sevoflurane-propofol (4.20 [3.28-5.39]), isoflurane-propofol (6.39 [4.90-8.34]), and total intravenous anesthesia (2.98 [2.22-3.98]). A RASS ≤-4 was also more likely with the use of dexmedetomidine (2.47 [2.10-2.89]), gabapentinoids (2.17 [1.90-2.48]), and midazolam (1.34 [1.21-1.49]). Deeply sedated patients discharged to general care wards had higher odds of opioid-induced respiratory complications (2.59 [1.32-5.10]) and higher odds of naloxone administration (2.93 [1.42-6.03])., Conclusions: Likelihood of deep sedation after recovery increased with intraoperative use of halogenated agents with higher solubility and increased further when propofol was concomitantly used. Patients who experience deep sedation during anesthesia recovery have an increased risk of opioid-induced respiratory complications on general care wards. These findings may be useful for tailoring anesthetic management to reduce postoperative oversedation., Competing Interests: Conflicts of Interest: See Disclosures at the end of the article., (Copyright © 2023 International Anesthesia Research Society.)

Purpose: Different organs have different autoregulatory capacities for blood pressure changes and/or circulatory volume changes. This study assessed the autoregulation of the stomach, liver, kidney and skeletal muscle, under baseline, hypovolemic, and post-fluid-resuscitation conditions using near-infrared spectroscopy (NIRS)., Methods: Ten pigs (bodyweight 24.5 ± 0.5 kg) were anesthetized with 2.5% isoflurane and administered 0.5, 1, 2 and 5 µg kg - 1  min - 1 of phenylephrine at 10-min intervals, followed by similar stepwise infusion of sodium nitroprusside (SNP) to induce a wide range of mean arterial pressures (MAPs). A 600-ml bleed was induced to create the hypovolemic condition, and only phenylephrine was re-administered. Hydroxyethyl starch (600 ml) was infused to create the post-fluid-resuscitation condition, and phenylephrine and SNP were re-administered. Average relationships between mean arterial pressure (MAP) and each tissue oxygenation index (TOI) were assessed, and the individual relationships were evaluated based on the correlation coefficients between MAP and TOI during each vasoactive drug infusion., Results: Based on the evaluation using each TOI as a substitute of blood flow, the kidney autoregulation was robust, similar to muscle, but had a prominent lower limit. The stomach had weaker autoregulation than the kidney and muscle. The liver had no autoregulation. The kidney TOI showed 2-fold greater changes in response to volume condition changes than the stomach and liver TOIs., Conclusion: In our NIRS-based assessment of autoregulatory capacity, the liver oxygenation is highly blood pressure dependent, and the kidney is highly susceptible and the skeletal muscle is highly tolerable to low blood pressure and volume loss., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Background: Emulsified isoflurane was designed to circumvent the deficiencies of inhalation anesthetics, which have a longer time to onset, result in a higher drug consumption, and for which a specific anesthesia machine is required for clinical use. The aim of this study was to compare the efficacy and safety of emulsified isoflurane with propofol for anesthesia induction in adults patients., Methods: This multicenter, randomized, double-blind, positive-controlled, non-inferiority, phase III clinical trial compared the efficacy and safety of emulsified isoflurane with propofol for anesthesia induction. Each patient in the emulsified isoflurane group received a single bolus injection of 12% emulsified isoflurane at a dose of 30 mg/kg, and each patient in the propofol group received a single bolus injection of 0.8% propofol at a dose of 2 mg/kg. The primary outcome of the efficacy evaluation was the proportion of participants with successful anesthesia induction, which was regarded as a Modified Observer's Assessment of Alertness/Sedation (MOAA/S) score of < 1 and lack of use of other sedative drugs. A number of secondary efficacy outcomes were also assessed. Safety was monitored based on (1) adverse events, (2) repeated measurement of vital signs; (3) physical examination, (4) routine laboratory examinations of hematology, biochemistry, urine, coagulation function, and (5) 12-lead electrocardiogram., Results: A total of 416 patients were enrolled (n = 208 in each group) and 398 patients were administered study drug. The proportion of participants with successful anesthesia induction was 100% with a 95% confidence interval of - 1.9% to + 1.9% for the emulsified isoflurane and propofol groups, which met the predesigned non-inferiority criteria of 5%. The study demonstrated the non-inferiority of sedation produced by emulsified isoflurane compared to propofol. Among the secondary efficacy outcomes, emulsified isoflurane showed a better cardiovascular stability than propofol. The number of patients from the emulsified isoflurane group who experienced drug-related adverse events was significantly higher than that of patients from the propofol group. However, there was no significant difference between the two groups in terms of adverse events or drug-related adverse events of grades 3-5., Conclusions: Emulsified isoflurane exhibited non-inferiority of anesthesia/sedation compared to propofol in patients undergoing anesthesia induction., Clinical Trial Registration: ChiCTR2000038185, registered on 12 December, 2020 ( www.chictr.org.cn )., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Dual practice, where physicians work both in public and private hospitals, is a widely observed phenomenon, particularly in developing countries. This paper studies a multi-stage game where hospitals compete for physicians as well as patients and, the service provided by physicians endogenously depends on the competitive setting in which hospitals operate. Specifically, we examine the impact of allowing dual practice on hospital payoffs, physician's service and societal welfare. We find that dual practice is socially desirable, since it softens the competition for physician's exclusive service while also increasing the amount of their service. However, if the degree of competition between the hospitals is significant, dual practice may not yield the highest payoffs for both public and private hospitals., (© 2022 John Wiley & Sons Ltd.)

Objective: To investigate the effect of transcranial direct current stimulation (tDCS) combined with conventional comprehensive rehabilitation on dysphagia after brainstem stroke., Materials and Methods: Forty brainstem stroke patients were randomly divided into tDCS group and conventional comprehensive treatment group, including 20 patients in each group. Both groups were given routine swallowing function training, and tDCS group added transcranial direct current stimulation (tDCS). The Dysphagia Outcome and Severity Scale (DOSS) and Functional Dysphagia Scale (FDS) were evaluated respectively before and after 8 weeks of continuous treatment with VFSS. The white blood cell (WBC), c-reactive protein, prealbumin (PAB), albumin (Alb), and hemoglobin (Hb) were also compared between the two groups before and after 8 weeks of continuous treatment., Results: After 8 consecutive weeks of treatment, the score of DOSS scale and FDS scale in both groups was improved (P < 0.05), WBC and CRP were decreased (P < 0.05), and Alb and Hb were improved (P < 0.05), and PAB had no differences (P=0.474). The tDCS group was superior to conventional comprehensive group in improving the swallowing function and nutritional indexes (P < 0.05)., Conclusions: tDCS therapy combined with routine training can improve the swallowing function and nutritional status of patients, and reduce infection., (© 2021. The Author(s).)

Background: Literature on bone marrow carcinomatosis in head and neck squamous cell carcinoma (HNSCC) is sparse. This work aims to augment understanding on its characteristic features, clinical presentation, investigations, treatment and outcomes., Methods: Comprehensive literature review of all published cases of metastasis of HNSCC to the bone marrow with regard to clinical presentation, diagnosis, treatment and survival outcomes of this disease. Each of these factors is discussed forming an up-to-date review on the subject., Results: Eight case reports were identified, seven males and one female with an age range of 35-64 years. Primary sites were from the oral cavity (n = 4), oropharynx (n = 3) and supraglottis (n = 1). Six were stage four disease with nodal involvement, one case stage two and one case with unknown staging. Two of the oropharyngeal cancers were p16 positive, and one p16 status was not documented. Five patients presented with back pain, two patients had ecchymoses with bleeding, and one presented with sepsis and thrombocytopaenia. Three patients had proven disseminated intravascular coagulation. Four patients were treated with palliative chemoradiotherapy, one had palliative radiotherapy, one had radiotherapy and dendritic cell vaccine immunotherapy, and two died from the disease prior to any treatment. Various facets of presentation and management are discussed., Conclusion: Bone marrow carcinomatosis from HNSCC is rare. It can present with a variety of non-specific symptoms, and a high index of suspicion is required to be able to diagnose the condition promptly. Aggressive chemotherapy is the treatment of choice but prognosis remains poor., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Oral hygiene management of patients with acute stroke is important for preventing aspiration pneumonia and ensuring oral intake. The tongue coating score can be useful for evaluating the oral hygiene level since it reflects the microorganism number on the tongue surface in elderly patients. However, the relationship between the number of oral microorganisms and the tongue coating score in patients with acute stroke remains unclear., Objectives: We aimed to investigate the relationships between the microorganism number on the tongue surface and oral factors, including tongue coating score, tongue surface moisture level and tongue function., Methods: This cross-sectional study enrolled 73 patients with acute stroke who were hospitalised at an acute care hospital and underwent dental intervention. Potential explanatory factors, including sex, age, Glasgow Coma Scale score, tongue coating score, tongue surface moisture level, nutrition intake method, number of functional teeth and tongue function, were evaluated. Logistic regression analysis determined their association with the microorganism number on the tongue surface., Results: The tongue coating score (odds ratio: 1.31) and tongue surface moisture level (odds ratio: 1.10) were significantly associated with increased microorganism numbers on the tongue surface., Conclusion: The tongue coating score, which reflects the actual number of microorganisms on the tongue surface, could be an effective tool for evaluating oral hygiene level in patients with stroke. Moreover, reducing oral microorganisms in saliva through oral hygiene management, including removing the tongue coating, could contribute towards the prevention of aspiration pneumonia., (© 2020 John Wiley & Sons Ltd.)

Purpose: Remimazolam, an ultra-short-acting benzodiazepine sedative is equally effective as propofol in induction and maintenance of general anesthesia with improved hemodynamic stability in American Society of Anesthesiologists (ASA) Class I and II patients. This trial investigated remimazolam's efficacy and safety in vulnerable patients (ASA Class III) undergoing elective general surgery., Methods: A multicenter, randomized, double-blind, parallel-group trial in 67 adult surgical patients undergoing general anesthesia with two remimazolam induction doses (6 mg kg -1  h -1 -group A and 12 mg kg -1  h -1 -group B) has been conducted in 6 trials sites in Japan. Remimazolam was infused up to 2 mg kg -1  h -1 for maintenance of anesthesia in both groups., Results: The functional anesthetic capability of the investigated drug was 100% in both arms. The mean time to loss of consciousness (LoC) was significantly shorter in group B (81.7 s) compared to group A (97.2 s), p = 0.0139. The mean bispectral index (BIS) value during maintenance of anesthesia ranged from 46.0 to 68.0 and from 44.7 to 67.5 in group A and B, respectively. There was no statistically significant difference between the remimazolam arms concerning the incidence of blood pressure (BP) decrease (67.7% in group B vs. 54.8% in group A), recovery profile or the incidence or severity of adverse events (AEs) or adverse drug reactions (ADRs)., Conclusion: Both induction regimens (6 and 12 mg kg -1  h -1 ) were equally efficacious and safe in surgical patients ASA Class III. A significantly shorter time to LoC was observed with the higher remimazolam dosage. Clinical trial registration This trial is registered with the Japan Pharmaceutical Information Center-Clinical Trials Information (JapicCTI). JapicCTI number: 121977.

Unlabelled: We have introduced a novel, parallel design into a new clinical bymixer (patent pending), named for the bypass of a constant fraction of total flow through a mixing chamber. Over a wide range of tidal volumes (300-1200 mL), frequency (6-20 breaths/min), and PCO(2) (6-50 mm Hg), the bymixer provided accurate measurement of mixed expired gas fractions in the ventilation circuit compared with an expired gas collection in a metabolic lung bench setup (average slope, 1.00; average y intercept, -0.01; average coefficient of determination, R(2) = 0.9988). Simple changes in mixing chamber volume provided adjustable bymixer response times. The fast bymixer response (time constant, 6.4 s) should allow measurements to be updated every 20 s (where 95% response occurs by three time constants). The new clinical bymixer is constructed from standard anesthesia circuit components, attaches easily to the anesthesia machine inspired outlet and expired inlet ports, is simple to clean and sterilize, and has no reservoir to trap condensed water vapor from expired gas. The new clinical bymixer may facilitate indirect calorimetry (CO(2) elimination, VCO(2), and oxygen uptake, VCO(2)) during anesthesia and the noninvasive detection of metabolic upset (e.g., onset of anaerobic metabolism) and critical events (e.g., pulmonary embolism)., Implications: A new clinical bymixer (inline mixing chamber) provides a fast response and accurate measurements of mixed expired gas fractions in the anesthesia circle circuit. A novel parallel design facilitates adjustable response, easy cleaning, and construction from standard airway circuit components. The new clinical bymixer may facilitate widespread introduction of indirect calorimetry during anesthesia.