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Background: Central venous access devices (CVADs) are an essential and widely used tool for the treatment of the critically ill, patients undergoing major surgery, and for many patients requiring hemodialysis. Automation of centrally inserted central catheters (CICCs) could potentially make CVAD placement safer, more effective, and more accessible. A new device that uses ultrasound image-guided, robotic needle placement, in addition to traditional Seldinger technique, to place a CICC is described., Objective: The device was used in a small, first-in-human, trial for placing non-tunneled hemodialysis catheters (NTHDCs), in order to determine feasibility of clinical use., Methods: Consecutive patients requiring a NTHDC, at one institution, over a 48 h period, were recruited to consent to placing the catheter by the device. Observations of safety, efficacy, and efficiency of the procedure were recorded., Results: There were 19 catheter placement attempts in 17 patients. All placements were successful (100%). The first placement attempt was successful in 16/19 catheterizations (84%). Two catheterizations required two attempts and one required three attempts. There were no complications for any catheterization. The device provided rapid access to the target central vein and required relatively little training time for operators., Conclusions: The study demonstrates the feasibility for clinical application of a novel central venous access robotic device., Competing Interests: Declaration of conflicting interestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: James P Herlihy and William E Cohn were co-founders of Obvius Robotics, makers of CERTA™, the device studied in this article, and are stakeholders in the company.

We assessed adverse events in hospitalized patients receiving selected vesicant antibiotics or vasopressors administered through midline catheters or peripherally inserted central catheters (PICC). The rates of catheter-related bloodstream infections, thrombosis, and overall events were similar across the two groups, while occlusion was higher in the PICC group., Competing Interests: All authors have nothing to disclose., (© Cambridge University Press 2024.)

Blood-culture overutilization is associated with increased cost and excessive antimicrobial use. We implemented an intervention in the adult intensive care unit (ICU), combining education based on the DISTRIBUTE algorithm and restriction to infectious diseases and ICU providers. Our intervention led to reduced blood-culture utilization without affecting safety metrics.

Background: Vasoplegia after cardiac surgery is associated with adverse outcomes. However, the clinical effects of vasoplegia and the significance of its duration after continuous-flow left ventricular assist device (CF-LVAD) implantation are less known., Objectives: This study aimed to identify predictors of and outcomes from transient vs prolonged vasoplegia after CF-LVAD implantation., Methods: The study was a retrospective review of consecutive patients who underwent CF-LVAD implantation between January 1, 2005, and December 31, 2017. Vasoplegia was defined as the presence of all of the following: mean arterial pressure ≤65 mm Hg, vasopressor (epinephrine, norepinephrine, vasopressin, or dopamine) use for >6 hours within the first 24 hours postoperatively, cardiac index ≥2.2 L/min/m 2 and systemic vascular resistance <800 dyne/s/cm 5 , and vasodilatory shock not attributable to other causes. Prolonged vasoplegia was defined as that lasting 12 to 24 hours; transient vasoplegia was that lasting 6 to <12 hours. Patient characteristics, outcomes, and risk factors were analyzed., Results: Of the 600 patients who underwent CF-LVAD implantation during the study period, 182 (30.3%) developed vasoplegia. Mean patient age was similar between the vasoplegia and no-vasoplegia groups. Prolonged vasoplegia (n = 78; 13.0%), compared with transient vasoplegia (n = 104; 17.3%), was associated with greater 30-day mortality (16.7% vs 5.8%; P  = 0.02). Risk factors for prolonged vasoplegia included preoperative dialysis and elevated body mass index., Conclusions: Compared with vasoplegia overall, prolonged vasoplegia was associated with worse survival after CF-LVAD implantation. Treatment to avoid or minimize progression to prolonged vasoplegia may be warranted., Competing Interests: Dr Nair is a consultant for Abbott; and has received speaking fees from Abbott and Impulse Dynamics. Dr Frazier has received travel support from BiVACOR Inc. Dr Loor has received institutional grant support to Baylor College of Medicine from Abiomed, Transmedics, Abbott, and Maquet; and is a consultant for Abiomed & TransMedics, and is a scientific advisor for TransMedics. Dr Shafii has received institutional grant support to Baylor College of Medicine from Abbott and Evaheart, Inc. Dr Chatterjee has served on advisory boards for Edwards Lifesciences, La Jolla Pharmaceutical Company, Baxter Pharmaceuticals, and Eagle Pharmaceuticals, Inc. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2024 The Authors.)

Background: Intensive care unit (ICU) prolonged immobilization may lead to lower-extremity muscle deconditioning among critically ill patients, particularly more accentuated in those with 2019 Novel Coronavirus (COVID-19) infection. Electrical stimulation (E-Stim) is known to improve musculoskeletal outcomes. This phase I double-blinded randomized controlled trial examined the safety and efficacy of lower-extremity E-Stim to prevent muscle deconditioning., Methods: Critically ill COVID-19 patients admitted to the ICU were randomly assigned to control (CG) or intervention (IG) groups. Both groups received daily E-Stim (1 h) for up to 14 days on both gastrocnemius muscles (GNMs). The device was functional in the IG and non-functional in the CG. Primary outcomes included ankle strength (Ankle s ) measured by an ankle-dynamometer, and GNM endurance (GNM e ) in response to E-Stim assessed with surface electromyography (sEMG). Outcomes were measured at baseline, 3 and 9 days., Results: Thirty-two (IG = 16, CG = 16) lower extremities in 16 patients were independently assessed. The mean time between ICU admission and E-Stim therapy delivery was 1.8 ± 1.9 days ( p = 0.29). At 3 days, the IG showed an improvement compared to the CG with medium effect sizes for Ankle s ( p = 0.06, Cohen's d = 0.77) and GNM e ( p = 0.06, d = 0.69). At 9 days, the IG GNM e was significantly higher than the CG ( p = 0.04, d = 0.97) with a 6.3% improvement from baseline ( p = 0.029). E-Stim did not alter vital signs (i.e., heart/respiratory rate, blood saturation of oxygen), showed no adverse events (i.e., pain, skin damage, discomfort), nor interfere with ICU standard of care procedures (i.e., mechanical ventilation, prone rotation)., Conclusion: This study supports the safety and efficacy of early E-Stim therapy to potentially prevent deterioration of lower-extremity muscle conditions in critically ill COVID-19 patients recently admitted to the ICU. If confirmed in a larger sample, E-Stim may be used as a practical adjunctive therapy., Clinical Trial Registration: [https://clinicaltrials.gov/], identifier [NCT04685213]., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zulbaran-Rojas, Mishra, Rodriguez, Bara, Lee, Bagheri, Herlihy, Siddique and Najafi.)

Patients with severe refractory hypoxemic respiratory failure may benefit from extracorporeal membrane oxygenation (ECMO) for salvage therapy. The Coronavirus disease 2019 (COVID-19) pandemic offered three high-volume independent ECMO programs at a large medical center the chance to collaborate to optimize ECMO care at the beginning of the pandemic in Spring 2020. Between March 15, 2020, and May 30, 2020, 3,615 inpatients with COVID-19 were treated at the Texas Medical Center. During this time, 35 COVID-19 patients were cannulated for ECMO, all but one in a veno-venous configuration. At hospital discharge, 23 (66%) of the 35 patients were alive. Twelve patients died of vasodilatory shock (n = 9), intracranial hemorrhage (n = 2), and cannulation-related bleeding and multiorgan dysfunction (n = 1). The average duration of ECMO was 13.6 days in survivors and 25.0 days in nonsurvivors ( p < 0.04). At 1 year follow-up, all 23 discharged patients were still alive, making the 1 year survival rate 66% (23/35). At 2 years follow-up, the overall rate of survival was 63% (22/35). Of those patients who survived 2 years, all were at home and alive and well at follow-up., Competing Interests: Disclosure: B.A. reports funding from ALung Technologies, CytoDyn, and CSL Behring as Primary Investigator. F.M. serves as a consultant for Portola Pharmaceuticals. S.C. has served on advisory boards for Edwards Lifesciences, Baxter Pharmaceuticals, and LaJolla Pharmaceuticals. The remaining authors have no conflicts of interest to report., (Copyright © ASAIO 2022.)

Context: Patients with severe respiratory failure from COVID-19 refractory to conventional therapies may be treated with extracorporeal membrane oxygenation (ECMO). ECMO requirement is associated with high mortality and prolonged hospital course. ECMO is a high-resource intervention with significant burdens placed on caregivers and families with limited data on the integration of palliative care consultation (PCC)., Objectives: To explore the role of standard vs. automatic PCC in the management of COVID patients on ECMO., Methods: Retrospective chart review of all COVID patients on ECMO admitted from March 2020 to May 2021 at a large volume academic medical center with subsequent analysis., Results: Forty-eight patients were included in the analysis. Twenty-six (54.2%) received PCC of which 42% of consults were automatically initiated. PCC at any point in admission was associated with longer duration on ECMO (24.5 vs. 37 days; P &lt; 0.05). Automatic PCC resulted in more family meetings than standard PCC (0 vs. 3; P &lt; 0.05) and appears to trend with reduced time on ECMO, shorter length of stay, and higher DNAR rates at death, though results were not significant. Decedents not receiving PCC had higher rates of no de-escalation of interventions at time of death (31% vs. 11%), indicating full intensive care measures continued through death., Conclusions: Among patients with COVID-19 receiving ECMO, PCC may be associated with a shift to DNAR status particularly with automatic PCC. There may be a further impact on length of stay, duration of time on ECMO and care plan at end of life., (Copyright © 2022 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.)

Competing Interests: Competing interests: None declared.

Introduction: This study sought to evaluate the impact of changes made to the process of continually screening hospitalized patients for decompensation., Methods: Patients admitted to hospital wards were screened using a cloud-based early warning score (modified National Early Warning Score [mNEWS]). Patient with mNEWS ≥7 triggered a structured response. Outcomes of this quality improvement study during the intervention period from February through August 2018 (1741 patients) were compared with a control population (1,610 patients) during the same months of 2017., Results: The intervention group improved the time to the first lactate order within 24 hours of mNEWS ≥7 (p < .001), the primary outcome, compared with the control group. There was no significant improvement in time to intensive care unit (ICU) transfer, ICU length of stay (LOS), or hospital mortality. Among patients with a lactate ordered within 24 hours, there was a 47% reduction of in-hospital mortality (odds ratio 0.53, 95% confidence interval 0.3-0.89, p = .02) and a 4.7 day reduction in hospital LOS (p < .001) for intervention versus control cohorts., Conclusions: Cloud-based electronic surveillance can result in earlier detection of clinical decompensation. This intervention resulted in lower hospital LOS and mortality among patients with early detection of and intervention for clinical decompensation., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2020 National Association for Healthcare Quality.)

Purpose: This study aimed to determine if sequential deployment of a nurse-led Rapid Response Team (RRT) and an intensivist-led Medical Emergency Team (MET) for critically ill patients in the Emergency Department (ED) and acute care wards improved hospital-wide cardiac arrest rates., Methods: In this single-center, retrospective observational cohort study, we compared the cardiac arrest rates per 1000 patient-days during two time periods. Our hospital instituted a nurse-led RRT in 2012 and added an intensivist-led MET in 2014. We compared the cardiac arrest rates during the nurse-led RRT period and the combined RRT-MET period. With the sequential approach, nurse-led RRT evaluated and managed rapid response calls in acute care wards and if required escalated care and co-managed with an intensivist-led MET. We specifically compared the rates of pulseless electrical activity (PEA) in the two periods. We also looked at the cardiac arrest rates in the ED as RRT-MET co-managed patients with the ED team., Results: Hospital-wide cardiac arrests decreased from 2.2 events per 1000 patient-days in the nurse-led RRT period to 0.8 events per 1000 patient-days in the combined RRT and MET period (p-value = 0.001). Hospital-wide PEA arrests and shockable rhythms both decreased significantly. PEA rhythms significantly decreased in acute care wards and the ED., Conclusion: Implementing an intensivist-led MET-RRT significantly decreased the overall cardiac arrest rate relative to the rate under a nurse-led RRT model. Additional MET capabilities and early initiation of advanced, time-sensitive therapies likely had the most impact., Competing Interests: The authors have declared that no competing interests exist.

Introduction: Noninvasive positive pressure ventilation (NIPPV) plays an important role in the management of respiratory failure. However, since the emergence of the COVID-19 pandemic, utilization of traditional face mask NIPPV has been curtailed in part due to risk of aerosolization of respiratory particles and subsequent health care worker exposure. A randomized clinical trial in 2016 reported that an alternative interface, helmet NIPPV, may be more effective than traditional NIPPV at preventing intubation and improving mortality. The helmet NIPPV interface provides positive airway pressure, while also theoretically minimizing aerosolization, making it a feasible modality in management of respiratory failure in COVID-19 patients., Case and Outcomes: This report describes a single-center experience of a series of three COVID-19 patients with hypoxemic respiratory failure managed with helmet NIPPV. One patient was able to avoid intubation while a second patient was successfully extubated to NIPPV. Ultimately, the third patient was unable to avoid intubation with helmet NIPPV, although the application of the device was late in the progression of the disease., Discussion: NIPPV is an important modality in the management of respiratory failure and has been shown to reduce the need for immediate endotracheal intubation in select populations. For patients unable to tolerate facemask NIPPV, the helmet provides an alternate interface. In COVID-19 patients, the helmet interface may reduce the risk of virus exposure to health care workers from aerosolization. Based on this experience, we recommend that helmet NIPPV can be considered as a feasible option for the management of patients with COVID-19, whether the goal is to prevent immediate intubation or avoid post-extubation respiratory failure. Randomized studies are needed to definitively validate the use of helmet NIPPV in this population., Conclusion: Helmet NIPPV is a feasible therapy to manage COVID-19 patients.

Competing Interests: Disclosure: The authors have no conflicts of interest to declare.

Extracorporeal membrane oxygenation (ECMO) has been used for more than 50 years as salvage therapy for patients with severe cardiopulmonary failure refractory to conventional treatment. ECMO was first used in the 1960s to treat hypoxemic respiratory failure in newborns. On the basis of its success in that population, ECMO began to be used in the early 1970s to treat adult hypoxemic respiratory failure. However, outcomes for adults were, somewhat perplexingly, quite poor. By the 1980s, use of ECMO for severe hypoxemia was rare outside of the pediatric population. ECMO technology, however, continued to evolve and improve. Multiple case reports and small series describing ECMO use as rescue for adults with severe hypoxemia from various lung pathologies have appeared in the literature over the past three decades. Adult respiratory distress syndrome (ARDS) is often the final common pathway of various pathologies affecting adults and causing hypoxemic respiratory failure. It is prevalent in intensive care units throughout the world and has, since it was first described in 1967, carried a high mortality. No specific therapy for ARDS has been found, and current care is supportive, primarily by mechanical ventilation. Results from recent randomized controlled trials, however, suggest that ECMO may have a place in the treatment of these patients. This article reviews these studies and recommends adding severe ARDS to the list of established indications for ECMO in patients with hypoxemic respiratory failure., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare., (2019 Journal of Thoracic Disease. All rights reserved.)

Background: Bleeding complications are common with extracorporeal membrane oxygenation (ECMO). We investigated whether a heparin monitoring protocol using activated partial thromboplastin time (aPTT) and thromboelastography (TEG) affected clinical outcomes., Methods: This retrospective chart review stratified cohorts by study interval: pre-protocol (January 2016-March 2017) or post-protocol (March 2017-December 2017). The protocol defined therapeutic anticoagulation as aPTT of 60-80 seconds and a TEG reaction (TEG-R) time of 2-4× baseline; pre-protocol management used aPTT alone. The primary endpoints were the rates of bleeding and thrombotic events (clinical/device thrombosis) as defined by Extracorporeal Life Support Organization (ELSO) guidelines. Secondary endpoints included time in therapeutic aPTT range, rate of physician compliance with the protocol, time to heparin initiation, intensive care unit length of stay, mortality, and antithrombin III (ATIII) supplementation., Results: The pre-protocol (n=72) and post-protocol (n=51) groups (age 60±12 years; 80% on venoarterial ECMO; average ECMO duration of 6 days) showed no difference in baseline characteristics. Major bleeding events occurred in 69% of pre-protocol patients, versus 67% of post-protocol patients (P=0.85). The post-protocol group had fewer retroperitoneal bleeds (P=0.01) and had a non-significantly lower rate of pulmonary or central nervous system (CNS) bleeding (P=0.07). Thrombotic events occurred in 21% of the pre-protocol group, versus 28% of the post-protocol group (P=0.39). Mortality during ECMO support was significantly lower in the post-protocol group (56.9% vs. 33.3%, P=0.01). The thrombosis rate was higher in patients who received ATIII than in those who did not (48.2% vs. 15.9%, P<0.01)., Conclusions: Major bleeding did not differ between the treatment groups. However, we observed significantly less mortality and retroperitoneal bleeding in the post-protocol group, suggesting an important gain from the intervention. Further study of the value of ATIII supplementation in ECMO patients is needed since we observed that a lower baseline ATIII level may indicate higher risk for thrombosis., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.

Amniotic fluid embolism is a leading cause of maternal mortality in developed countries. Our understanding of risk factors, diagnosis, treatment, and prognosis is hampered by a lack of uniform clinical case definition; neither histologic nor laboratory findings have been identified unique to this condition. Amniotic fluid embolism is often overdiagnosed in critically ill peripartum women, particularly when an element of coagulopathy is involved. Previously proposed case definitions for amniotic fluid embolism are nonspecific, and when viewed through the eyes of individuals with experience in critical care obstetrics, would include women with a number of medical conditions much more common than amniotic fluid embolism. We convened a working group under the auspices of a committee of the Society for Maternal-Fetal Medicine and the Amniotic Fluid Embolism Foundation whose task was to develop uniform diagnostic criteria for the research reporting of amniotic fluid embolism. These criteria rely on the presence of the classic triad of hemodynamic and respiratory compromise accompanied by strictly defined disseminated intravascular coagulopathy. It is anticipated that limiting research reports involving amniotic fluid embolism to women who meet these criteria will enhance the validity of published data and assist in the identification of risk factors, effective treatments, and possibly useful biomarkers for this condition. A registry has been established in conjunction with the Perinatal Research Branch of the Eunice Kennedy Shriver National Institute of Child Health and Human Development to collect both clinical information and laboratory specimens of women with suspected amniotic fluid embolism in the hopes of identifying unique biomarkers of this condition., (Copyright © 2016 Elsevier Inc. All rights reserved.)

We describe the initial--and successful--use of the TandemHeart System's catheters to provide extracorporeal membrane oxygenation (ECMO), in 2 patients. In 1 patient, who was experiencing severe primary respiratory failure, the catheters provided a standard venovenous ECMO circuit. In the other patient, who had severe, acute pulmonary hypertension and right-heart failure, the catheters enabled a novel right atrial-to-left atrial circuit for ECMO. We discuss the potential of the TandemHeart System's catheters to provide novel and possibly superior vascular routes for the delivery of ECMO in different types of cardiopulmonary failure.

Pleural effusions that are caused by congestive heart failure and refractory to medical management are rare, and the options for treating them are few and sometimes ineffective. We report here our experience, over a 2-year period, with a novel device, the Denver Biomedical PleurX pleural catheter, in treating a series of 5 patients who had chronic, refractory, heart-failure-associated pleural effusions. The PleurX catheter is a small-bore chest tube designed to remain in place for prolonged periods, through which drainage of pleural fluid can be performed easily on a daily or less frequent outpatient basis. Placement of the catheter, in our series, was associated with no complications. In all patients, the catheter effectively drained the pleural space initially, thereby controlling the effusions and alleviating New York Heart Association functional class IV symptoms. The catheters remained in place for a period of 1 to 15 months. In 2 of the patients, the catheter was associated with no complications during the time that it remained in place. One of these patients had the catheter removed at heart transplantation, and 1 retained the catheter until death from underlying heart disease. For 1 patient, the catheter resulted in a partially loculated pleural space, and it was removed. In 2 patients, after prolonged use, it was associated with empyema, for which it was removed. We conclude that the PleurX catheter can effectively control refractory congestive-heart-failure-associated pleural effusions temporarily, but that its prolonged use can cause significant complications, most importantly empyema.

In order to determine the temporal pattern of weaning from mechanical ventilation for patients undergoing prolonged mechanical ventilation after cardiac surgery, we performed a retrospective review of 21 patients' weaning courses at our long-term acute care hospital. Using multiple regression analysis of an estimate of individual patients' percentage of mechanical ventilator support per day (%MVSD), we determined that 14 of 21 patients (67%) showed a statistically significant quadratic or cubic relationship between time and % MVSD. These patients showed little or no improvement in their ventilator dependence until a point in time when, abruptly, they began to make rapid progress (a "wean turning point"), after which they progressed to discontinuation of mechanical ventilation in a relatively short period of time. The other 7 patients appeared to have a similar weaning pattern, although the data were not statistically significant. Most patients in the study group weaned from the ventilator through a specific temporal pattern that is newly described herein. Data analysis suggested that the mechanism for the development of a wean turning point was improvement of pulmonary mechanics rather than improvement in gas exchange or respiratory load. Although these observations need to be confirmed by a prospective trial, they may have implications for weaning cardiac surgery patients from prolonged mechanical ventilation, and possibly for weaning a broader group of patients who require prolonged mechanical ventilation.

A 57-year-old man who had received an automatic implantable cardioverter defibrillator and subsequent orthotopic heart transplant presented to medical attention for hemoptysis. The hemoptysis was caused by the migration of the left ventricular patch of the automatic implantable cardioverter defibrillator, which had been left in place at the time of orthotopic heart transplant. The patch had eroded into the left lung. We recommend that implantable cardioverter defibrillators be removed completely at the time of heart transplantation to prevent subsequent complications.

Polymorphonuclear leukocytes (PMN) are recruited to the lungs to defend against injury and infection. However, PMN undergo apoptosis, thereby losing functional ability within hours, and die with lysis soon thereafter unless they receive specific signals preventing this phenomenon. We hypothesized that alveolar macrophages (AM) could provide these signals. Therefore AM, obtained through bronchoalveolar lavage of healthy volunteers (n = 9), were cultured for 24 h, after which the AM conditioned media (AM-CM) were removed. Freshly isolated PMN, which showed no apoptosis, were suspended in AM-CM, as well as in unconditioned media (UM), and followed over 48 h for apoptosis and survival. In eight of nine patients, AM-CM contained tumor necrosis factor (TNF), which modestly delayed AM apoptosis so that the percentage of PMN apoptotic at 24 h was 77 +/- 6% in AM-CM compared with 91 +/- 2% in UM (P < 0.05). In one patient, urticaria developed early in the lavage, and this subject's AM-CM profoundly prevented apoptosis of PMN (to 10% at 24 h). PMN survival in this patient was similarly enhanced, so that at 48 h of culture it was 60%, compared with 45 +/- 8% in AM-CM and 30 +/- 6% in UM (P < 0.05 UM vs. AM-CM). Granulocyte/macrophage colony-stimulating factor (GM-CSF), in addition to TNF-alpha, partly accounted for this medium's activity. Thus AM can delay apoptosis in PMN through production of TNF-alpha and in some cases by GM-CSF. When activated in vivo by conditions such as an allergic reaction, AM can rapidly and profoundly suppress PMN apoptosis.

The high incidence of both bacterial pneumonia and the adult respiratory distress syndrome (ARDS) associated with smoke inhalation injury (SII) may result, at least in part, from smoke-induced injury to the alveolar macrophage (AM). Specifically, we hypothesized that AM antimicrobial function, ability to phagocytose apoptotic PMNs, and capacity to prevent apoptosis in PMNs are impaired by smoke. To test these hypotheses, AMs were harvested by bronchoalveolar lavage from sheep before and after the animal was exposed to cotton smoke. The two populations of AMs were incubated with Pseudomonas aeruginosa (PSA) in vitro. Normal AMs (NAMs) phagocytosed a mean of 99 +/- 11% of the PSA placed in their wells, whereas smoke-exposed AMs (SAMs) ingested only 60 +/- 8%. NAMs killed 80 +/- 8% of PSA ingested, whereas SAMs killed only 56 +/- 16% (P < 0.05). When sheep PMNs, allowed to undergo apoptosis, were incubated with the two AM populations, 66 +/- 3% of the NAMs and 40 +/- 6% of the SAMs demonstrated phagocytosis of these apoptotic PMNs (P < 0.05). Fresh sheep PMNs were incubated in unconditioned media, NAM and SAM-conditioned media, and followed over 48 hr for the development of apoptosis and maintenance of viability. The NAM-conditioned media markedly prevented apoptosis and augmented PMN survival relative to the unconditioned and SAM-conditioned media (P < 0.05). The poor antimicrobial function known to be characteristic of apoptotic PMNs, together with the directly impaired antimicrobial function of AMs, may contribute to the infectious complications of SII. If the PMNs recruited to the lung in SII are not properly supported by the AMs following smoke injury, large numbers may undergo apoptosis. If not properly disposed of by these SAMs, the apoptotic PMNs could eventually lyse, releasing tissue toxins, resulting in escalation of lung injury and leading to ARDS.

In single lung transplantation (SLT) recipients, a "plateau" of the maximal expiratory flow volume curve (MEFV) and a "biphasic" MEFV have been reported to reflect anastomosis pathology. A plateau is defined as constant airflow over a large expired volume early in the MEFV. A biphasic MEFV has an initial period of high flow followed by a terminal low flow phase. Models of expiratory flow limitation by wave speed, however, predict that the MEFV of SLT recipients with emphysema should both be biphasic and demonstrate a plateau even without anastomosis pathology. Review of the spirometries and clinical courses of our first ten patients receiving SLT for emphysema demonstrated a biphasic MEFV, and a plateau of the MEFV in all patients. No patient showed evidence of anastomosis pathology. Independent lung spirometries, generated by a novel technique, revealed that the initial high flow phase of the MEFV came from the transplanted lung and the terminal low flow from the native emphysematous lung. The location of the flow limitation was demonstrated to be immediately downstream from the anastomosis. Therefore, the MEFV of SLT recipients with emphysema routinely demonstrates both a biphasic pattern and a plateau, neither of which necessarily reflect anastomosis pathology.

After irradiation of the neck for a squamous cell carcinoma of the tonsillar pillar and vocal cord, a 71-year-old man presented with a rapidly progressive sleep apnea syndrome. Previous reports describe the condition of patients with obstructive sleep apnea that developed after neck irradiation and secondary to supraglottic edema. Our patient had an obstructive component to his apnea similar to that described in previous cases, but, in addition, he had hypothyroidism. Myxedema is a well-described cause of both obstructive and central apnea. We believe both contributed to his condition. He was successfully treated by placement of a tracheostomy and by thyroid supplementation. In patients who present with sleep apnea after neck irradiation, especially with acute or severe symptoms, the differential diagnosis should include both a central cause from hypothyroidism as well as a peripheral obstructive cause from laryngeal edema.