Automatic CPAP Compared with Conventional Treatment for Episodic Hypoxemia and Sleep Disturbance after Major Abdominal Surgery

Abstract: ContextHypoxemia complicates the recovery of 30% to 50% of patients after abdominal surgery; endotracheal intubation and mechanical ventilation may be required in 8% to 10% of cases, increasing morbidity and mortality and prolonging intensive care unit and hospital stay.ObjectiveTo determine the effectiveness of continuous positive airway pressure compared with standard treatment in preventing the need for intubation and mechanical ventilation in patients who develop acute hypoxemia after elective major abdominal surgery.Design and SettingRandomized, controlled, unblinded study with concealed allocation conducted between June 2002 and November 2003 at 15 intensive care units of the Piedmont Intensive Care Units Network in Italy.PatientsConsecutive patients who developed severe hypoxemia after major elective abdominal surgery. The trial was stopped for efficacy after 209 patients had been enrolled.InterventionsPatients were randomly assigned to receive oxygen (n = 104) or oxygen plus continuous positive airway pressure (n = 105).Main Outcome MeasuresThe primary end point was incidence of endotracheal intubation; secondary end points were intensive care unit and hospital lengths of stay, incidence of pneumonia, infection and sepsis, and hospital mortality.ResultsPatients who received oxygen plus continuous positive airway pressure had a lower intubation rate (1% vs 10%; P = .005; relative risk [RR], 0.099; 95% confidence interval [CI], 0.01-0.76) and had a lower occurrence rate of pneumonia (2% vs 10%, RR, 0.19; 95% CI, 0.04-0.88; P = .02), infection (3% vs 10%, RR, 0.27; 95% CI, 0.07-0.94; P = .03), and sepsis (2% vs 9%; RR, 0.22; 95% CI, 0.04-0.99; P = .03) than did patients treated with oxygen alone. Patients who received oxygen plus continuous positive airway pressure also spent fewer mean (SD) days in the intensive care unit (1.4 [1.6] vs 2.6 [4.2], P = .09) than patients treated with oxygen alone. The treatments did not affect the mean (SD) days that patients spent in the hospital (15 [13] vs 17 [15], respectively; P = .10). None of those treated with oxygen plus continuous positive airway pressure died in the hospital while 3 deaths occurred among those treated with oxygen alone (P = .12).ConclusionContinuous positive airway pressure may decrease the incidence of endotracheal intubation and other severe complications in patients who develop hypoxemia after elective major abdominal surgery.

Abstract: Background Obstructive sleep apnea (OSA) is present in a significant proportion of the population, but the majority of patients remain undiagnosed It is crucial that anesthesiologists and surgeons recognize the increased perioperative risks associated with undiagnosed OSA We present a systematic review of the literature on the perioperative management of surgical patients with OSA Methods The scope of this review is restricted to publications in all surgical specialties and in the adult patient population The main search key words were: "perioperative care," "sleep apnea," "obstructive sleep apnea," "perioperative risk," and "perioperative care" The databases Medline, Embase, Biological Abstract, Science Citation Index, and Healthstar were searched for relevant English language articles from 1966 to March 2007 Results The literature supports an increased perioperative risk in OSA patients The American Society of Anesthesiologists guidelines support the routine screening for OSA during preoperative assessment, and methods of OSA screening are discussed in this review This review suggests a number of perioperative management strategies to reduce surgical risk in patients with OSA However, apart from the consensus-based American Society of Anesthesiologists guidelines, it is important to note that evidence-based recommendations are lacking in the literature Conclusions This review suggests ways to screen for OSA in the preoperative setting and proposes perioperative management strategies The ultimate goal is to reduce the perioperative risk of OSA patients but, to realize that goal, research will be needed to determine whether screening for OSA and/or adapting specific perioperative management approaches translates into a lessening of adverse events in surgical patients with undiagnosed OSA

Abstract: Objective:We evaluated the potential benefit of continuous positive airway pressure (CPAP) to prevent postoperative pulmonary complications (PPCs), atelectasis, pneumonia, and intubation in patients undergoing major abdominal surgery.Summary Background Data:PPCs are common during the postoperative p

Abstract: Background Major abdominal surgery can be associated with a number of serious complications that may impair patient recovery. In particular, postoperative pulmonary complications (PPCs), including respiratory complications such as atelectasis and pneumonia, are a major contributor to postoperative morbidity and may even contribute to increased mortality. Continuous positive airway pressure (CPAP) is a type of therapy that uses a high-pressure gas source to deliver constant positive pressure to the airways throughout both inspiration and expiration. This approach is expected to prevent some pulmonary complications, thus reducing mortality. Objectives To determine whether any difference can be found in the rate of mortality and adverse events following major abdominal surgery in patients treated postoperatively with CPAP versus standard care, which may include traditional oxygen delivery systems, physiotherapy and incentive spirometry. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL) 2013, Issue 9; Ovid MEDLINE (1966 to 15 September 2013); EMBASE (1988 to 15 September 2013); Web of Science (to September 2013) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (to September 2013). Selection criteria We included all randomized controlled trials (RCTs) in which CPAP was compared with standard care for prevention of postoperative mortality and adverse events following major abdominal surgery. We included all adults (adults as defined by individual studies) of both sexes. The intervention of CPAP was applied during the postoperative period. We excluded studies in which participants had received PEEP during surgery. Data collection and analysis Two review authors independently selected studies that met the selection criteria from all studies identified by the search strategy. Two review authors extracted the data and assessed risk of bias separately, using a data extraction form. Data entry into RevMan was performed by one review author and was checked by another for accuracy. We performed a limited meta-analysis and constructed a summary of findings table. Main results We selected 10 studies for inclusion in the review from 5236 studies identified in the search. These 10 studies included a total of 709 participants. Risk of bias for the included studies was assessed as high in six studies and as unclear in four studies. Two RCTs reported all-cause mortality. Among 413 participants, there was no clear evidence of a difference in mortality between CPAP and control groups, and considerable heterogeneity between trials was noted (risk ratio (RR) 1.28, 95% confidence interval (CI) 0.35 to 4.66; I2 = 75%). Six studies reported demonstrable atelectasis in the study population. A reduction in atelectasis was observed in the CPAP group, although heterogeneity between studies was substantial (RR 0.62, 95% CI 0.45 to 0.86; I2 = 61%). Pneumonia was reported in five studies, including 563 participants; CPAP reduced the rate of pneumonia, and no important heterogeneity was noted (RR 0.43, 95% CI 0.21 to 0.84; I2 = 0%). The number of participants identified as having serious hypoxia was reported in two studies, with no clear difference between CPAP and control groups, given imprecise results and substantial heterogeneity between trials (RR 0.48, 95% CI 0.22 to 1.02; I2 = 67%). A reduced rate of reintubation was reported in the CPAP group compared with the control group in two studies, and no important heterogeneity was identified (RR 0.14, 95% CI 0.03 to 0.58; I2 = 0%). Admission into the intensive care unit (ICU) for invasive ventilation and supportive care was reduced in the CPAP group, but this finding did not reach statistical significance (RR 0.45, 95% CI 0.18 to 1.14; I2 = 0). Secondary outcomes such as length of hospital stay and adverse effects were only minimally reported. A summary of findings table was constructed using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) principle. The quality of evidence was determined to be very low. Authors' conclusions Very low-quality evidence from this review suggests that CPAP initiated during the postoperative period might reduce postoperative atelectasis, pneumonia and reintubation, but its effects on mortality, hypoxia or invasive ventilation are uncertain. Evidence is not sufficiently strong to confirm the benefits or harms of CPAP during the postoperative period in those undergoing major abdominal surgery. Most of the included studies did not report on adverse effects attributed to CPAP. New, high-quality research is much needed to evaluate the use of CPAP in preventing mortality and morbidity following major abdominal surgery. With increasing availability of CPAP to our surgical patients and its potential to improve outcomes (possibly in conjunction with intraoperative lung protective ventilation strategies), unanswered questions regarding its efficacy and safety need to be addressed. Any future study must report on the adverse effects of CPAP.

Abstract: BACKGROUND:Obstructive sleep apnea (OSA) is a commonly encountered comorbid condition in patients undergoing surgery and is associated with a greater risk of postoperative adverse events. Our objective in this review was to investigate the effectiveness of continuous positive airway pressure (CPAP)

Abstract: Blood pressure, heart rate, sympathetic nerve activity, and polysomnography were recorded during wakefulness and sleep in 10 patients with obstructive sleep apnea. Measurements were also obtained after treatment with continuous positive airway pressure (CPAP) in four patients. Awake sympathetic activity was also measured in 10 age- and sex-matched control subjects and in 5 obese subjects without a history of sleep apnea. Patients with sleep apnea had high levels of nerve activity even when awake (P < 0.001). Blood pressure and sympathetic nerve activity did not fall during any stage of sleep. Mean blood pressure was 92 +/- 4.5 mmHg when awake and reached peak levels of 116 +/- 5 and 127 +/- 7 mmHg during stage II sleep (n = 10) and rapid eye movement (REM) sleep (n = 5), respectively (P < 0.001). Sympathetic activity increased during sleep (P = 0.01) especially during stage II (133 +/- 9% above wakefulness; P = 0.006) and REM (141 +/- 13%; P = 0.007). Peak sympathetic activity (measured over the last 10 s of each apneic event) increased to 299 +/- 96% during stage II sleep and to 246 +/- 36% during REM sleep (both P < 0.001). CPAP decreased sympathetic activity and blood pressure during sleep (P < 0.03). We conclude that patients with obstructive sleep apnea have high sympathetic activity when awake, with further increases in blood pressure and sympathetic activity during sleep. These increases are attenuated by treatment with CPAP.

Abstract: Objectives: To obtain reliable estimates of the effects of neuraxial blockade with epidural or spinal anaesthesia on postoperative morbidity and mortality. Design: Systematic review of all trials with randomisation to intraoperative neuraxial blockade or not. Studies: 141 trials including 9559 patients for which data were available before 1 January 1997. Trials were eligible irrespective of their primary aims, concomitant use of general anaesthesia, publication status, or language. Trials were identified by extensive search methods, and substantial amounts of data were obtained or confirmed by correspondence with trialists. Main outcome measures: All cause mortality, deep vein thrombosis, pulmonary embolism, myocardial infarction, transfusion requirements, pneumonia, other infections, respiratory depression, and renal failure. Results: Overall mortality was reduced by about a third in patients allocated to neuraxial blockade (103 deaths/4871 patients versus 144/4688 patients, odds ratio=0.70, 95% confidence interval 0.54 to 0.90, P=0.006). Neuraxial blockade reduced the odds of deep vein thrombosis by 44%, pulmonary embolism by 55%, transfusion requirements by 50%, pneumonia by 39%, and respiratory depression by 59% (all P Conclusions: Neuraxial blockade reduces postoperative mortality and other serious complications. The size of some of these benefits remains uncertain, and further research is required to determine whether these effects are due solely to benefits of neuraxial blockade or partly to avoidance of general anaesthesia. Nevertheless, these findings support more widespread use of neuraxial blockade.

Abstract: We performed meta-analyses of randomized, control trials to assess the effects of seven analgesic therapies on postoperative pulmonary function after a variety of procedures: epidural opioid, epidural local anesthetic, epidural opioid with local anesthetic, thoracic versus lumbar epidural opioid, intercostal nerve block, wound infiltration with local anesthetic, and intrapleural local anesthetic. Measures of forced expiratory volume in 1 s (FEV,), forced vital capacity (FVC), vital capacity (VC), peak expiratory flow rate (PEFR), Pao,, and incidence of atelectasis, pulmonary infection, and pulmonary complications overall were analyzed. Compared with systemic opioids, epidural opioids decreased the incidence of atelectasis (risk ratio [RR] 0.53, 95% confidence interval [CI] 0.33-0.85) and had a weak tendency to reduce the incidence of pulmonaryinfections (RRO.53,95% CIO.18-1.53) and pulmonary complications overall (RR 0.51, 95% CI 0.20-1.33). Epidural local anesthetics increased Pao, (difference 4.56 mm Hg, 95% CI 0.058-9.075) and decreased the incidence of pulmonary infections (RR 0.36,95% CI 0.21-0.65) and pulmonary complications overall (RR 0.58,95% CI 0.42-0.80) compared with systemic opioids. Intercostal nerve blockade tends to improve pulmonary outcome measures (incidence of atelectasis: RR 0.65,95% CI 0.271.57, incidence of pulmonary complications overall: RR 0.47, 95% CI 0X3-1.22), but these differences did not achieve statistical significance. There were no clinically or statistically significant differences in the surrogate measures of pulmonary function (FEV,, FVC, and PEFR). These analyses support the utility of epidural analgesia for reducing postoperative pulmonary morbidity but do not support the use of surrogate measures of pulmonary outcome as predictors or determinants of pulmonary morbidity in postoperative patients. Implications: When individual trials are unable to produce significant results, it is often because of insufficient patient numbers. It may be impossible for a single institution to study enough patients. Meta-analysis is a useful tool for combining the data from multiple trials to increase the patient numbers. These meta-analyses confirm that postoperative epidural pain control can significantly decrease the incidence of pulmonary morbidity.

Abstract: We performed meta-analyses of randomized, control trials to assess the effects of seven analgesic therapies on postoperative pulmonary function after a variety of procedures: epidural opioid, epidural local anesthetic, epidural opioid with local anesthetic, thoracic versus lumbar epidural opioid, in