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Obstructive sleep apnea-hypopnea syndrome (OSAHS) is characterized by repetitive episodes of airflow reduction (hypopnea) or cessation (apnea) due to upper airway collapse during sleep. Increasing recognition and a greater understanding of the scope of this condition have substantially affected the practices of many clinicians. This review provides practical information for physicians assessing patients with OSAHS. It discusses complications, clinical recognition, the polysomnographic report, and treatment of OSAHS, including strategies for troubleshooting problems associated with continuous positive airway pressure therapy. [ABSTRACT FROM AUTHOR]

Background: Not all hypercapnic COPD patients benefit from home noninvasive ventilation (NIV), and mechanisms through which NIV improves clinical outcomes remain uncertain. We aimed to identify "responders" to home NIV, denoted by a beneficial effect of NIV on arterial partial pressure of carbon dioxide ( P aCO 2 ), health-related quality of life (HRQoL) and survival, and investigated whether NIV achieves its beneficial effect through an improved P aCO 2 ., Methods: We used individual patient data from previous published trials collated for a systematic review. Linear mixed-effect models were conducted to compare the effect of NIV on P aCO 2 , HRQoL and survival, within subgroups defined by patient and treatment characteristics. Secondly, we conducted a causal mediation analysis to investigate whether the effect of NIV is mediated by a change in P aCO 2 ., Findings: Data of 1142 participants from 16 studies were used. Participants treated with lower pressure support (<14 versus ≥14 cmH 2 O) and with lower adherence (<5 versus ≥5 h·day -1 ) had less improvement in P aCO 2 (mean difference (MD) -0.30 kPa, p<0.001 and -0.29 kPa, p<0.001, respectively) and HRQoL (standardised MD 0.10, p=0.002 and 0.11, p=0.02, respectively), but this effect did not persist to survival. P aCO 2 improved more in patients with severe dyspnoea (MD -0.30, p=0.02), and HRQoL improved only in participants with fewer than three exacerbations (standardised MD 0.52, p=0.03). The results of the mediation analysis showed that the effect on HRQoL is mediated partially (23%) by a change in P aCO 2 ., Interpretation: With greater pressure support and better daily NIV usage, a larger improvement in P aCO 2 and HRQoL is achieved. Importantly, we demonstrated that the beneficial effect of home NIV on HRQoL is only partially mediated through a reduction in diurnal P aCO 2 ., Competing Interests: Conflict of interest: T. Raveling reports a travel grant from Breas Medical. N.S. Hill reports consulting fees from Philips, consulting fees and payments from Fisher & Paykel, and participates in boards of Breas and Philips. C. Casanova reports consulting fees from AstraZeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Menarini and Novartis, and participates in boards of AstraZeneca and GlaxoSmithKline. E. Clini reports consulting fees from Chiesi Italia and Novartis, payments from AstraZeneca, Boehringer Ingelheim and GaxoSmithKline, and meeting/travel support from Boehringer Ingelheim and Chiesi. T. Köhnlein reports support from Grifols Deutschland GmbH. P.B. Murphy reports grants and payments from Fisher & Paykel, Resmed, Breas Medical and Philips Respironics, and payments from Chiesi and Genzyme. M.L. Duiverman reports grants from Resmed, Philips, Lowenstein, Vivisol, Sencure and Fisher & Paykel, and payments from Chiesi and Breas Medical. P.J. Wijkstra reports grants from Resmed, and grants and consulting fees from Philips., (Copyright ©The authors 2024.)

Objective: Excessive daytime sleepiness (EDS) is common in obstructive sleep apnea (OSA) and has been linked to adverse outcomes, albeit inconsistently. Furthermore, whether the prognostic impact of EDS differs as a function of sex is unclear. We aimed to assess the associations between EDS and chronic diseases and mortality in men and women with OSA., Methods: Newly-diagnosed adult OSA patients who underwent sleep evaluation at Mayo Clinic between November 2009 and April 2017 and completed the Epworth Sleepiness Scale (ESS) for assessment of perceived sleepiness ( N  = 14,823) were included. Multivariable-adjusted regression models were used to investigate the relationships between sleepiness, with ESS modeled as a binary (ESS > 10) and as a continuous variable, and chronic diseases and all-cause mortality., Results: In cross-sectional analysis, ESS > 10 was independently associated with lower risk of hypertension in male OSA patients (odds ratio [OR], 95% confidence interval [CI]: 0.76, 0.69-0.83) and with higher risk of diabetes mellitus in both OSA men (OR, 1.17, 95% CI 1.05-1.31) and women (OR 1.26, 95% CI 1.10-1.45). Sex-specific curvilinear relations between ESS score and depression and cancer were noted. After a median 6.2 (4.5-8.1) years of follow-up, the hazard ratio for all-cause death in OSA women with ESS > 10 compared to those with ESS ≤ 10 was 1.24 (95% CI 1.05-1.47), after adjusting for demographics, sleep characteristics and comorbidities at baseline. In men, sleepiness was not associated with mortality., Conclusion: The implications of EDS for morbidity and mortality risk in OSA are sex-dependent, with hypersomnolence being independently associated with greater vulnerability to premature death only in female patients. Efforts to mitigate mortality risk and restore daytime vigilance in women with OSA should be prioritized., Competing Interests: EO is a member of the Board of Directors of the American Academy of Sleep Medicine. VS serves as a consultant for ResMed, Jazz Pharmaceuticals, Bayer, Lilly, Sleep Number, Zoll, Respicardia, and Huxley. The remaining 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 © 2023 Covassin, Lu, St. Louis, Chahal, Schulte, Mansukhani, Xie, Lipford, Li, Ramar, Caples, Gay, Olson, Silber, Li and Somers.)

This article addresses the issue of patient sleep during hospitalization, which the Society of Anesthesia and Sleep Medicine believes merits wider consideration by health authorities than it has received to date. Adequate sleep is fundamental to health and well-being, and insufficiencies in its duration, quality, or timing have adverse effects that are acutely evident. These include cardiovascular dysfunction, impaired ventilatory function, cognitive impairment, increased pain perception, psychomotor disturbance (including increased fall risk), psychological disturbance (including anxiety and depression), metabolic dysfunction (including increased insulin resistance and catabolic propensity), and immune dysfunction and proinflammatory effects (increasing infection risk and pain generation). All these changes negatively impact health status and are counterproductive to recovery from illness and operation. Hospitalization challenges sleep in a variety of ways. These challenges include environmental factors such as noise, bright light, and overnight awakenings for observations, interventions, and transfers; physiological factors such as pain, dyspnea, bowel or urinary dysfunction, or discomfort from therapeutic devices; psychological factors such as stress and anxiety; care-related factors including medications or medication withdrawal; and preexisting sleep disorders that may not be recognized or adequately managed. Many of these challenges appear readily addressable. The key to doing so is to give sleep greater priority, with attention directed at ensuring that patients' sleep needs are recognized and met, both within the hospital and beyond. Requirements include staff education, creation of protocols to enhance the prospect of sleep needs being addressed, and improvement in hospital design to mitigate environmental disturbances. Hospitals and health care providers have a duty to provide, to the greatest extent possible, appropriate preconditions for healing. Accumulating evidence suggests that these preconditions include adequate patient sleep duration and quality. The Society of Anesthesia and Sleep Medicine calls for systematic changes in the approach of hospital leadership and staff to this issue. Measures required include incorporation of optimization of patient sleep into the objectives of perioperative and general patient care guidelines. These steps should be complemented by further research into the impact of hospitalization on sleep, the effects of poor sleep on health outcomes after hospitalization, and assessment of interventions to improve it., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2023 International Anesthesia Research Society.)

As more patients depend upon mechanical or electronic technologies for treatment, medical device recalls-like the recent recall of common positive airway pressure treatment devices-impact millions of patients, often causing significant anxiety, extra costs, and interruption of care for patients. When recalls require health care and/durable medical equipment providers to be part of the solution, the burden on practices and businesses can be significant, creating strains on access for new patients and on limited medical supplies. We have observed that having an established and well-organized medical device recall plan in place allows for a rapid response, decreased practice burden, and reduced provider stress. Coupling the organized response with proactive, empathic, and clear communication with patients reduces their anxiety, provides clear directions for how to address the issue constructively, and reduces reactive communications. We share what we believe are key components of a medical device and produce recall procedure as we describe our institutions response in hopes that others can build on these basics as they design their own response plans., Citation: Morgenthaler TI, Linginfelter EA, Gay PC, et al. Rapid response to medical device recalls: an organized patient-centered team effort. J Clin Sleep Med. 2022;18(2):663-667., (© 2022 American Academy of Sleep Medicine.)

Objectives: With over 2 million cases of acute respiratory failure in the United States per year, noninvasive ventilation has become a leading treatment modality, often supplanting invasive mechanical ventilation as the initial treatment of choice. Most acute respiratory failure patients use a full face (oronasal) mask with noninvasive ventilation, which is known to impair communication, but its popularity and benefit has led many providers to accept the communication impairment. Medical staff periodically remove masks to communicate with patients, but patients are often limited to short utterances and risk lung derecruitment upon removal of positive pressure. These problems can lead to noninvasive ventilation failure, which is often linked to worse outcomes than first initiating invasive mechanical ventilation and can lead to increased hospitalization costs., Data Sources: We searched MEDLINE and Google Scholar for "speech," "communication," "impairment," "failure," "complications," "NIPPV," "NIV," and "noninvasive ventilation.", Study Selection: We included articles with patients in acute respiratory failure. We excluded articles for patients using noninvasive ventilation therapy for obstructive sleep apnea., Data Synthesis: Communication impairment has been associated with increasing noninvasive ventilation anxiety (odds ratio, 1.25). Of patients using noninvasive ventilation, 48% require early discontinuation, 22% refuse noninvasive ventilation, and 9% are ultimately intubated. Improvements to communication have been shown to reduce fear and anxiety in invasive mechanical ventilation patients. Analogous communication problems exist with effective solutions in other fields, such as fighter pilot masks, that can be easily implemented to enhance noninvasive ventilation patient care, increase adherence to noninvasive ventilation treatment, and improve patient outcomes., Conclusions: Communication impairment is an underappreciated cause of noninvasive ventilation complications and failure and requires further characterization. Analogous solutions-such as throat microphones and mask-based microphones-that can be easily implemented show potential as cost-effective methods to reduce noninvasive ventilation failure., Competing Interests: Dr. Wong is Chief Medical Officer of Ataia Medical and has received an industry grant for NCT03795753. Dr. Happ holds copyright to the Study of Patient-Nurse Effectiveness with Assisted Communication Strategies (SPEACS-2) online communication training program, no personal earnings. Dr. Happ collaborated with industry on augmentative and alternative communication technology development and testing, as principal investigator in collaboration with Vidatak, LLC on grant number 2R42NR014087-02 as consultant to Voxello on grant number 5R44 NR016406-03S. The remaining authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2020 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the Society of Critical Care Medicine.)

Citation: Javaheri S, Gay PC. To die, to sleep - to sleep, perchance to dream…without hypertension: dreams of the visionary Christian Guilleminault revisited. J Clin Sleep Med. 2019;15(9):1189-1190., (© 2019 American Academy of Sleep Medicine.)

Study Objectives: Adaptive servoventilation (ASV) is the suggested treatment for many forms of central sleep apnea (CSA). We aimed to evaluate the impact of treating CSA with ASV on health care utilization., Methods: In this population-based study using the Rochester Epidemiology Project database, we identified patients over a 9-year period who were diagnosed with CSA (n = 1,237), commenced ASV therapy, and had ≥ 1 month of clinical data before and after ASV initiation. The rates of hospitalizations, emergency department visits (EDV), outpatient visits (OPV) and medications prescribed per year (mean ± standard deviation) in the 2 years pre-ASV and post-ASV initiation were compared., Results: We found 309 patients (68.0 ± 14.6 years, 80.3% male, apnea-hypopnea index 41.6 ± 26.5 events/h, 78% with cardiovascular comorbidities, 34% with heart failure) who met inclusion criteria; 65% used ASV ≥ 4 h/night on ≥ 70% nights in their first month. The overall 2-year mortality rate was 9.4% and CSA secondary to cardiac cause was a significant risk factor for mortality (hazard ratio 1.81, 95% CI 1.09-3.01, P = .02). Comparing pre-ASV and post-ASV initiation, there was no change in the rate of hospitalization (0.72 ± 1.63 versus 0.79 ± 1.44, P = .46), EDV (1.19 ± 2.18 versus 1.26 ± 2.08, P = .54), OPV (31.59 ± 112.42 versus 13.60 ± 17.36, P = .22), or number of prescribed medications (6.68 ± 2.0 versus 5.31 ± 5.86, P = .06). No differences in these outcomes emerged after accounting for adherence to ASV, CSA subtype and comorbidities via multiple regression analysis (all P > .05)., Conclusions: Our cohort of patients with CSA was quite ill and the use of ASV was not associated with a change in health care utilization., (© 2019 American Academy of Sleep Medicine.)

Acute respiratory compromise describes a deterioration in respiratory function with a high likelihood of rapid progression to respiratory failure and death. Identifying patients at risk for respiratory compromise coupled with monitoring of patients who have developed respiratory compromise might allow earlier interventions to prevent or mitigate further decompensation. The National Association for the Medical Direction of Respiratory Care (NAMDRC) organized a workshop meeting with representation from many national societies to address the unmet needs of respiratory compromise from a clinical practice perspective. Respiratory compromise may arise de novo or may complicate preexisting lung disease. The group identified distinct subsets of respiratory compromise that present similar opportunities for early detection and useful intervention to prevent respiratory failure. The subtypes were characterized by the pathophysiological mechanisms they had in common: impaired control of breathing, impaired airway protection, parenchymal lung disease, increased airway resistance, hydrostatic pulmonary edema, and right-ventricular failure. Classification of acutely ill respiratory patients into one or more of these categories may help in selecting the screening and monitoring strategies that are most appropriate for the patient's particular pathophysiology. Standardized screening and monitoring practices for patients with similar mechanisms of deterioration may enhance the ability to predict respiratory failure early and prevent its occurrence., (Copyright © 2017 by Daedalus Enterprises.)

Background: Continuous positive airway pressure (CPAP) is considered the treatment of choice for obstructive sleep apnea (OSA), and studies have shown that there is a correlation between patient adherence and treatment outcomes. Newer CPAP machines can track adherence, hours of use, mask leak, and residual apnea-hypopnea index (AHI). Such data provide a strong platform to examine OSA outcomes in a chronic disease management model. However, there are no standards for capturing CPAP adherence data, scoring flow signals, or measuring mask leak, or for how clinicians should use these data., Methods: American Thoracic Society (ATS) committee members were invited, based on their expertise in OSA and CPAP monitoring. Their conclusions were based on both empirical evidence identified by a comprehensive literature review and clinical experience., Results: CPAP usage can be reliably determined from CPAP tracking systems, but the residual events (apnea/hypopnea) and leak data are not as easy to interpret as CPAP usage and the definitions of these parameters differ among CPAP manufacturers. Nonetheless, ends of the spectrum (very high or low values for residual events or mask leak) appear to be clinically meaningful., Conclusions: Providers need to understand how to interpret CPAP adherence tracking data. CPAP tracking systems are able to reliably track CPAP adherence. Nomenclature on the CPAP adherence tracking reports needs to be standardized between manufacturers and AHIFlow should be used to describe residual events. Studies should be performed examining the usefulness of the CPAP tracking systems and how these systems affect OSA outcomes.

Background: Patients with do-not-intubate (DNI) status and respiratory failure are commonly treated with noninvasive ventilation (NIV). High-flow nasal cannula (HFNC) therapy supplies a high flow of heated and humidified oxygen that may provide an effective alternative to NIV. We assessed the efficacy of HFNC in DNI patients with hypoxemic respiratory distress., Methods: We identified 50 DNI patients with hypoxemic respiratory distress who were admitted to a medical ICU and who received HFNC. We excluded patients with PaCO2 > 65 mm Hg and pH < 7.28. The primary end point was the need for escalation to NIV, as determined by the primary service. Mean changes in oxygen saturation and breathing frequency before and after HFNC were compared., Results: The subjects included 25 men and 25 women, mean age 73 years (range 27-96 y). Diagnoses (allowing multiple conditions) included pulmonary fibrosis (15), pneumonia (15), COPD (12), cancer (7), hematologic malignancy (7), and congestive heart failure (3). Hospital mortality was 60% (30/50). HFNC was initiated at a mean FIO2 of 0.67 (range 0.30-1.0) and flow of 42.6 L/min (range 30-60 L/min). Mean O2 saturations went from 89.1% to 94.7% (P < .001), and breathing frequency went from 30.6 breaths/min to 24.7 breaths/min (P < .001). Nine of the 50 subjects (18%) escalated to NIV, while 82% were maintained on HFNC. The median duration of HFNC was 30 hours (range 2-144 h)., Conclusions: HFNC can provide adequate oxygenation for many patients with hypoxemic respiratory failure and may be an alternative to NIV for DNI patients.

Background: Obstructive sleep apnoea (OSA) is often undiagnosed before elective surgery and may predispose patients to perioperative complications., Methods: A literature search of PubMed-Medline, Web of Science, Scopus, EMBASE, Cochrane Database of Systematic Reviews, and Cochrane Central Register of Controlled Trials up to November 2010 was conducted. Our search was restricted to cohort or case-control studies in adults diagnosed with OSA by screening questionnaire, oximetry, or polysomnography. Studies without controls, involving upper airway surgery, and with OSA diagnosed by ICD-9 codes alone were excluded. The primary postoperative outcomes were desaturation, acute respiratory failure (ARF), reintubation, myocardial infarction/ischaemia, arrhythmias, cardiac arrest, intensive care unit (ICU) transfer, and length of stay., Results: Thirteen studies were included in the final analysis (n=3942). OSA was associated with significantly higher odds of any postoperative cardiac events [45/1195 (3.76%) vs 24/1420 (1.69%); odds ratio (OR) 2.07; 95% confidence interval (CI) 1.23-3.50, P=0.007] and ARF [33/1680 (1.96%) vs 24/3421 (0.70%); OR 2.43, 95% CI 1.34-4.39, P=0.003]. Effects were not heterogeneous for these outcomes (I(2)=0-15%, P>0.3). OSA was also significantly associated with higher odds of desaturation [189/1764 (10.71%) vs 105/1881 (5.58%); OR 2.27, 95% CI 1.20-4.26, P=0.01] and ICU transfer [105/2062 (5.09%) vs 58/3681 (1.57%), respectively; OR 2.81, 95% CI 1.46-5.43, P=0.002]. Both outcomes showed a significant degree of heterogeneity of the effect among studies (I(2)=57-68%, P<0.02). Subgroup analyses had similar conclusions as main analyses., Conclusions: The incidence of postoperative desaturation, respiratory failure, postoperative cardiac events, and ICU transfers was higher in patients with OSA.

Study Objectives: We hypothesized that early intervention with an auto bilevel device would improve treatment adherence compared to CPAP among OSA patients with a poor initial experience with lab-based CPAP titration., Methods: Patients with a poor initial CPAP experience were recruited for this parallel group, randomized, double-blind, controlled pilot study. After an in-lab titration, patients were randomized with either an auto-bilevel device or CPAP. Treatment adherence and functioning were assessed at 90 days., Results: We enrolled 51 subjects, with 47 completing the protocol. Groups were equally matched for gender, age, education, and OSA severity. There was no significant difference in the proportion of compliant subjects (≥ 4 h/night) between the auto bilevel and CPAP groups (62% vs. 54%; p = 0.624) after 90 days of use. Functional outcomes significantly improved in both groups during treatment use (p < 0.001) but did not differ between groups., Conclusions: There was no statistically significant difference in adherence between the auto bilevel and CPAP groups in this study. Patients with a poor initial CPAP exposure may still achieve an acceptable long-term clinical outcome. Both groups demonstrated comparably significant improvements in functional outcomes, sleepiness, and fatigue complaints over the treatment period. CLINICAL TRIALS INFORMATION: NCT00635206 ClinicalTrials.gov

Background: An increasing number of patients require prolonged mechanical ventilation (PMV), which is associated with high morbidity and poor long-term survival, but there are few data regarding the incidence and outcome of PMV patients from a community perspective., Methods: We retrospectively reviewed the electronic medical records of adult Olmsted county, Minnesota, residents admitted to the intensive care units at the 2 Mayo Clinic Rochester hospitals from January 1, 2003, to December 31, 2007, who underwent tracheostomy for PMV., Results: Sixty-five patients, median age 68 years (interquartile range [IQR] 49-80 y), 39 male, underwent tracheostomy for PMV, resulting in an age-adjusted incidence of 13 (95% CI 10-17) per 100,000 patient-years at risk. The median number of days on mechanical ventilation was 24 days (IQR 18-37 d). Forty-six patients (71%) survived to hospital discharge, and 36 (55%) were alive at 1-year follow-up. After adjusting for age and baseline severity of illness, the presence of COPD was independently associated with 1-year mortality (hazard ratio 3.4, 95% CI 1.4-8.2%)., Conclusions: There was a considerable incidence of tracheostomy for PMV. The presence of COPD was an independent predictor of 1-year mortality.

Background: Patients with obstructive sleep apnea are at risk for perioperative morbidity. The authors used a screening prediction model for obstructive sleep apnea to generate a sleep apnea clinical score (SACS) that identified patients at high or low risk for obstructive sleep apnea. This was combined with postanesthesia care unit (PACU) monitoring with the aim of identifying patients at high risk of postoperative oxygen desaturation and respiratory complications., Methods: In this prospective cohort study, surgical patients with a hospital stay longer than 48 h who consented were enrolled. The SACS (high or low risk) was calculated; all patients were monitored in the PACU for recurrent episodes of bradypnea, apnea, desaturations, and pain-sedation mismatch. All patients underwent pulse oximetry postoperatively; complications were documented. Chi-square, two-sample t test, and logistic regression were used for analysis. The oxygen desaturation index (number of desaturations per hour) was calculated. Oxygen desaturation index and incidence of postoperative cardiorespiratory complications were primary endpoints., Results: Six hundred ninety-three patients were enrolled. From multivariable logistic regression analysis, the likelihood of a postoperative oxygen desaturation index greater than 10 was increased with a high SACS (odds ratio = 1.9, P < 0.001) and recurrent PACU events (odds ratio = 1.5, P = 0.036). Postoperative respiratory events were also associated with a high SACS (odds ratio = 3.5, P < 0.001) and recurrent PACU events (odds ratio = 21.0, P < 0.001)., Conclusions: Combination of an obstructive sleep apnea screening tool preoperatively (SACS) and recurrent PACU respiratory events was associated with a higher oxygen desaturation index and postoperative respiratory complications. A two-phase process to identify patients at higher risk for perioperative respiratory desaturations and complications may be useful to stratify and manage surgical patients postoperatively.

Study Objectives: Despite widespread agreement that continuous positive airway pressure is effective therapy for obstructive sleep apnea, it is estimated that 50% of patients recommended for therapy are noncompliant 1 year later. Interventions to improve compliance in such patients have not been studied. We evaluated a 2 phase intervention program to improve compliance in sleep apnea patients previously noncompliant with continuous positive airway pressure., Methods: 204 patients with previously diagnosed obstructive sleep apnea and noncompliant with continuous positive airway pressure were enrolled. Phase 1 evaluated standard interventions to improve therapy compliance, including mask optimization, heated humidification, topical nasal therapy, and sleep apnea education. Persistently noncompliant patients proceeded to phase 2, where compliance was compared in double-blind randomized fashion between standard continuous positive airway pressure and flexible bilevel positive airway pressure., Results: 49 (24%) of 204 previously noncompliant patients became compliant (average nightly use > or =4 hours) after standard interventions. Then 104 of the 155 persistently noncompliant patients agreed to continue and were randomized to either CPAP or flexible bilevel positive airway pressure retitration and treatment for an additional ninety days. At follow-up 15 (28%) of the 53 randomized to CPAP and 25 (49%) of the 51 randomized to flexible bilevel positive airway pressure (p = 0.03) achieved compliance., Conclusions: A two phase intervention program, first employing standard interventions, followed by a change to flexible bilevel airway pressure, can achieve improved compliance in patients previously noncompliant with continuous positive airway pressure.

Study Objectives: Obstructive sleep apnea (OSA) has been associated with increased perioperative morbidity and mortality. We initiated a protocol designed to screen patients preoperatively and monitor them postoperatively. The goal was to identify patients who were at risk for oxygen desaturation after discharge from the postanesthesia recovery room (PACU)., Methods: Patients without previously diagnosed OSA presenting to the preoperative evaluation clinic were assessed over a 10.5-month period using a validated prediction rule to identify patients thought to be at high risk of OSA (sleep apnea clinical score, SACS > or = 15). Following surgery, patients were monitored in the PACU for significant respiratory events: apnea, increased FiO2 requirement, pain-sedation mismatch, or episodes of desaturation. Patients were placed in 3 groups based on their SACS and the presence or absence of recurrent PACU respiratory events (group 1: SACS < 15, no recurrent events; group 2: SACS > or =15, no recurrent events; and group 3: SACS > or = 15, recurrent events.) The number of oxygen desaturations > or = 4% per hour, the oxygen desaturation index (ODI), was calculated for each patient for 24 to 48 hours after PACU discharge. An ODI > 10 was the threshold chosen to indicate a high frequency of oxygen desaturation., Results: The percentage of patients with ODI > 10 differed significantly across the 3 study groups (12%, 37%, and 57%, for groups 1-3, p = 0.005). Mean ODI in group 1 was significantly different from groups 2 and 3 (5.8 compared to 10.0 group 2 and 11.4 group 3 with p = 0.001)., Conclusions: We have shown that combining preoperative screening is useful for identifying patients at risk for oxygen desaturation after PACU discharge.

Introduction: The role of non-invasive positive pressure ventilation (NIPPV) in the treatment of acute lung injury (ALI) is controversial. We sought to assess the outcome of ALI that was initially treated with NIPPV and to identify specific risk factors for NIPPV failure., Methods: In this observational cohort study at the two intensive care units of a tertiary center, we identified consecutive patients with ALI who were initially treated with NIPPV. Data on demographics, APACHE III scores, degree of hypoxemia, ALI risk factors and NIPPV respiratory parameters were recorded. Univariate and multivariate regression analyses were performed to identify risk factors for NIPPV failure., Results: Of 79 consecutive patients who met the inclusion criteria, 23 were excluded because of a do not resuscitate order and two did not give research authorization. Of the remaining 54 patients, 38 (70.3%) failed NIPPV, among them all 19 patients with shock. In a stepwise logistic regression restricted to patients without shock, metabolic acidosis (odds ratio 1.27, 95% confidence interval (CI) 1.03 to 0.07 per unit of base deficit) and severe hypoxemia (odds ratio 1.03, 95%CI 1.01 to 1.05 per unit decrease in ratio of arterial partial pressure of O2 and inspired O2 concentration--PaO2/FiO2) predicted NIPPV failure. In patients who failed NIPPV, the observed mortality was higher than APACHE predicted mortality (68% versus 39%, p < 0.01)., Conclusion: NIPPV should be tried very cautiously or not at all in patients with ALI who have shock, metabolic acidosis or profound hypoxemia.

Noninvasive positive pressure ventilation (NPPV) is usually applied using pressure support ventilation (PSV). Proportional assist ventilation (PAV) is a newer mode that delivers assisted ventilation in proportion to patient effort. We hypothesized that PAV for NPPV would support gas exchange and avoid intubation as well as PSV and be more comfortable and tolerable for patients. Adult patients with acute respiratory insufficiency were randomized to receive NPPV with PAV delivered using the Respironics Vision ventilator or PSV using a Puritan-Bennett 7200ae critical care ventilator. Each mode was adjusted to relieve dyspnea and improve gas exchange until patients met weaning or intubation criteria, died, or refused to continue. Twenty-one and 23 patients were entered into the PAV and PSV groups, respectively, and had similar diagnoses and baseline characteristics, although pH was slightly lower in the PAV group (7.30 versus 7.35, p = 0.02). Mortality and intubation rates were similar, but refusal rate was lower, reduction in respiratory rate was more rapid, and there were fewer complications in the PAV group. We conclude that use of the PAV mode is feasible for noninvasive therapy of acute respiratory insufficiency. Compared with PSV delivered with the Puritan-Bennett 7200ae, PAV is associated with more rapid improvements in some physiologic variables and is better tolerated.

Objective: To identify and assess the impact of postoperative complications in patients with unrecognized or known obstructive sleep apnea syndrome (OSAS) undergoing hip replacement or knee replacement compared with control patients undergoing similar operations. Although OSAS is a risk factor for perioperative morbidity, data quantifying the magnitude of the problem in patients undergoing non-upper airway operations are limited., Patients and Methods: This retrospective, case-control study from a single academic medical institution included patients diagnosed as having OSAS between January 1995 and December 1998 and undergoing hip or knee replacement within 3 years before or anytime after their OSAS diagnosis. Patients with OSAS were subcategorized as having the diagnosis either before or after the surgery and also, regardless of time of diagnosis, by whether they were using continuous positive airway pressure (CPAP) prior to hospitalization. Matched controls were patients without OSAS undergoing the same operation. Interventions were defined specifically as administration of a particular treatment in the context of each complication, eg, supplemental oxygen, implementation of additional monitoring such as oximetry for hypoxemia, or transfer to the intensive care unit (ICU) for cardiac ischemia concerns. Postoperative complications were assessed for all patients in the different categories and included respiratory events such as hypoxemia, acute hypercapnia, and episodes of delirium. Serious complications were noted separately, including unplanned ICU days, reintubations, and cardiac events. The length of hospital stay was also tabulated., Results: There were 101 patients with the diagnosis of OSAS in this study and 101 matched controls. Thirty-six patients had their joint replacement before OSAS was diagnosed, and 65 had surgery after OSAS was diagnosed. Of the latter 65 patients, only 33 were using CPAP at home preoperatively. Complications were noted in 39 patients (39%) in the OSAS group and 18 patients (18%) in the control group (P=.001). Serious complications occurred in 24 patients (24%) in the OSAS group compared with 9 patients (9%) in the control group (P=.004). Hospital stay was significantly longer for the OSAS patients at a mean +/- SD of 6.8 +/- 2.8 days compared with 5.1 +/- 4.1 days for the control patients (P<.007)., Conclusion: Adverse postoperative outcomes occurred at a higher rate in patients with a diagnosis of OSAS undergoing hip or knee replacement compared with a group of matched control patients.

Noninvasive ventilation refers to the delivery of assisted ventilatory support without the use of an endotracheal tube. Noninvasive positive pressure ventilation (NPPV) can be delivered by using a volume-controlled ventilator, a pressure-controlled ventilator, a bilevel positive airway pressure ventilator, or a continuous positive airway pressure device. During the past decade, there has been a resurgence in the use of noninvasive ventilation, fueled by advances in technology and clinical trials evaluating its use. Several manufacturers produce portable devices that are simple to operate. This review describes the equipment, techniques, and complications associated with NPPV and also the indications for both short-term and long-term applications. NPPV clearly represents an important addition to the techniques available to manage patients with respiratory failure. Future clinical trials evaluating its many clinical applications will help to define populations of patients most apt to benefit from this type of treatment.

Objective: To evaluate the efficacy of nocturnal nasal ventilation (NNV) in patients with rigidly defined, severe but stable chronic obstructive pulmonary disease (COPD) and hypercapnia., Design: By randomization, eligible patients were assigned to an active or a sham treatment arm. Data from these two groups were analyzed statistically., Material and Methods: Initially, 35 patients with severe COPD (forced expiratory volume in 1 second [FEV1] of less than 40% predicted) and daytime hypercapnia (arterial carbon dioxide tension [PaCO2] of more than 45 mm Hg) were enrolled in a 3-month NNV trial. After a minimal observation period of 6 weeks, 13 patients were judged to be clinically stable and were randomized to NNV (N = 7) or sham (N = 6) treatment, consisting of nightly use of a bilevel positive airway pressure (PAP) device set to deliver an inspiratory pressure of either 10 or 0 cm of water (H2O). The device was used in the spontaneous or timed mode and set to a minimal expiratory pressure of 2 cm H2O. Patients underwent extensive physiologic testing including polysomnography and were introduced to the bilevel PAP system during a 2.5-day hospital stay., Results: The NNV and sham treatment groups were similar in mean age (71.0 versus 66.5 years), PaCO2 (54.7 versus 48.5 mm Hg), and FEV1 (0.62 versus 0.72 L). Only four of seven patients in the NNV group were still using the bilevel PAP device at the completion of the trial, as opposed to all six patients in the sham group. Only one patient had a substantial reduction in PaCO2 - from 50 mm Hg at baseline to 43 mm Hg after 3 months of NNV. He declined further NNV treatment with bilevel PAP. Sham treatment did not lower PaCO2. Lung function, nocturnal oxygen saturation, and sleep efficiency remained unchanged in both groups., Conclusion: Disabled but clinically stable patients with COPD and hypercapnia do not readily accept and are unlikely to benefit from NNV.

Objective: To increase the general awareness of the possible exacerbation of hypercapnia by the administration of low-flow oxygen in patients with neuromuscular disorders., Design: We retrospectively reviewed the medical records of 118 consecutive adult patients with a diagnosis of neuromuscular disease who underwent phrenic nerve conduction studies during a 5-year period, and we analyzed pulmonary function data for 8 patients who underwent arterial blood gas studies before and after the administration of low-flow oxygen., Material and Methods: In the eight patients with neuromuscular disease and diaphragmatic dysfunction (three with polymyositis, three with amyotrophic lateral sclerosis or nonspecific motor neuron disease, and one each with inflammatory motor neuropathy and chronic poliomyelitis), we analyzed the response of the arterial carbon dioxide tension (PaCO2) after low-flow supplemental oxygen therapy (0.5 to 2 L/min). Linear analysis was used to attempt to find correlations between respiratory variables and the PaCO2 response after oxygen therapy., Results: For the overall study group, the mean PaCO2 increased 28.2 +/- 23.3 torr after low-flow oxygen treatment; in five patients, it increased by 27 torr or more. Four patients who were subsequently treated with nocturnal assisted ventilation were able to use supplemental oxygen during the day with less severe hypercapnia. Statistical analysis failed to reveal specific correlations between increased PaCO2 values after oxygen therapy and any respiratory variables., Conclusion: In patients with neuromuscular disease and diaphragmatic dysfunction, even low-flow supplemental oxygen should be administered with caution, and assisted ventilation should be strongly considered as an initial intervention.

We retrospectively reviewed the pulmonary complications and associated morbidity and mortality of 44 consecutive patients who underwent 52 orthotopic liver transplantations (OLTs) at the Mayo Clinic during 1987. All survivors participated in follow-up for 1 year after OLT. Of the five deaths in the study group, three were associated with pulmonary infections. On postoperative chest roentgenograms, 24 cases of pulmonary infiltrates were noted; 12 were caused by infections. Ten opportunistic pulmonary infections developed in nine patients: four cytomegalovirus, three Pneumocystis carinii pneumonia, and one each of Cryptococcus, Aspergillus, and Candida. All except one of the opportunistic infections were diagnosed after the sixth postoperative week. Fiberoptic bronchoscopy was helpful for diagnosing opportunistic pulmonary infections in six patients. One Aspergillus pulmonary infection was diagnosed by transthoracic needle aspiration. Bacterial pneumonia occurred in five patients. Preoperative pulmonary function tests, performed in 40 patients, revealed a restrictive ventilatory defect in 28% and impaired gas transfer in 52%. Pleural effusion was present in 18% of patients preoperatively and in 77% during the first week after OLT. Preoperative severity of liver disease and results of arterial blood gas determinations, pulmonary function tests, and chest roentgenography were not associated with postoperative mortality and pulmonary infections. Infectious and noninfectious pulmonary complications are common in liver transplant recipients. Attempts to decrease the frequency and severity of pulmonary complications by early diagnosis and effective treatment may diminish the morbidity and mortality associated with OLT.

Apolipoproteins were measured in a prospective blinded fashion in blood specimens from patients with chest pain in the emergency department. A definitive diagnosis for the chest pain (non-cardiac-related in 32% and angina or myocardial infarction in 68%) was available in 136 of the 162 patients originally enrolled in the study. Logistic regression and multivariate analysis failed to show any usefulness of apolipoprotein determinations in distinguishing patients with cardiac ischemia from those without it. The clinician's initial impression of the chest pain, the electrocardiogram, a history of previous angina, myocardial infarction, or peripheral atherosclerosis, and male sex were strongly associated with the final diagnosis. We conclude that, although apolipoprotein analysis has proved useful in epidemiologic studies, the most reliable indicators of ischemic pain remain the medical history, the electrocardiogram, and the clinician's overall initial impression.

Breathing abnormalities and nocturnal hypoventilation occur in patients with amyotrophic lateral sclerosis (ALS). A prospective study was undertaken to determine the relationship of pulmonary function test abnormalities with quality of sleep and survival in 21 patients with ALS. Results of spirometry including determination of maximal respiratory pressures and arterial blood gases were compared with several formal polysomnographic variables and then also with 18-month survival. The patients had mild to moderate pulmonary function deficits, but the quality of sleep was best related to age (mean age, 58.5 years). The results of pulmonary function tests and arterial blood gas measurements did not correlate well with the presence of nocturnal breathing events or survival time, but the maximal inspiratory pressure was 86% sensitive for predicting the presence of a nocturnal oxygen saturation nadir of 80% or less and 100% sensitive for predicting 18-month survival. Although obstructive breathing events occurred, the primary explanation for the decline in nocturnal oxygen saturation was hypoventilation. We conclude that routine pulmonary function tests may be useful for screening for reductions in nocturnal oxygen saturation and also may have prognostic value. Further studies may determine whether treatment of nocturnal hypoventilation will have an effect on survival in patients with ALS who have breathing impairment.

We reviewed the Mayo Clinic experience with nocturnal nasal ventilation (NNV) and retrospectively assessed the clinical benefits, patient compliance, and complications. NNV had been instituted in 26 patients with daytime hypercapnia and nocturnal hypoventilation due to neuromuscular diseases or chronic obstructive pulmonary disease. After initiation of NNV, 21 of 26 patients continued to use this treatment regularly (81% compliance rate) and considered their life-style improved. In this subset of patients, the arterial partial pressure of carbon dioxide during unassisted breathing decreased from 64 +/- 13 to 51 +/- 7 mm Hg, and the arterial partial pressure of oxygen increased from 58 +/- 12 to 68 +/- 8 mm Hg. No significant change was noted in the forced vital capacity or maximal respiratory pressures. Four of the five patients in whom NNV had been discontinued cited discomfort related to the mask or severity and poor prognosis of the underlying illness as reasons for cessation of treatment. We conclude that NNV is well tolerated by most patients and may improve alveolar ventilation and arterial oxygenation in patients with chronic respiratory failure.

Portable chest radiography is an essential component of clinical patient management in the intensive-care unit. With routine use of this procedure, unexpected cardiopulmonary abnormalities are frequently detected, and malposition or complications of intravascular devices and endotracheal, thoracostomy, or nasogastric tubes are also commonly found. The pulmonary parenchyma may be assessed for changes of acute lung injury, cardiogenic edema, areas of pneumonitis, atelectasis, or other abnormal collections of fluid or air. In mechanically ventilated patients, barotrauma occurs frequently and may be manifested by subtle intrathoracic collections of air. Technical factors may limit the resolution of the anteroposterior chest radiograph obtained at the bedside, but crucial clinical information is often gained. Portable chest radiographic findings, the role of computed tomography and ultrasonography, and interventional radiologic procedures pertinent to patients in the intensive-care unit are reviewed.

For the past 50 years, basic research has provided valuable insights into the concepts of respiratory system mechanics, but clinical application in the critical-care arena remains in its infancy. On the basis of the limited information that is available on critically ill patients, we believe that physicians who are responsible for the care of mechanically ventilated patients must understand the mechanical interactions between humans and machines. With measurements of flow, volume, and pressure, a more precise quantitative evaluation of the respiratory system can be obtained than with clinical assessment alone. In this article, we discuss the principles, techniques, and clinical applications of measurements of respiratory system mechanics in ventilated patients and suggest directions for further research that may prove to be clinically relevant.

We reviewed the records of all patients who underwent bronchoscopy with a flexible fiberoptic instrument and transbronchial needle aspiration (TBNA) at our institution between August 1983 and December 1985. During 85 bronchoscopy sessions, 89 TBNAs were performed in 84 patients. Seventy-three aspirates were obtained from 68 patients who were eventually proved to have a malignant lesion. Of these 68 patients, 25 had positive results of TBNA (37%). Of these 25 patients, 15 had non-small-cell cancers (11 bronchogenic and 4 metastatic from extrapulmonary sites), and 10 had small-cell carcinomas. In patients with a malignant lesion, 23% of the central aspirates (from paratracheal regions or within 2 cm of the carina) and 65% of the distal aspirates (beyond 2 cm from the carina) were positive (a total yield of 34%). Five of the distal aspirates were obtained from peripheral lesions under fluoroscopic guidance, and three were positive for a malignant process. In eight patients, the only malignant finding at bronchoscopy was the aspirate. Two of the eight patients had carcinoma metastatic to the lung, three had small-cell carcinoma, and the other three had bronchogenic carcinoma. In five patients, TBNA obviated more invasive diagnostic measures. We find TBNA to be useful in selected patients. It increases our diagnostic yield for small-cell carcinoma and carcinoma metastatic to the chest. TBNA should be considered when a submucosal process is present, extrinsic compression is evident, or an accessible extrabronchial mass is found radiographically.