Major surgery is still associated with undesirable sequelae such as pain, cardiopulmonary, infective and thromboembolic complications, cerebral dysfunction, nausea and gastrointestinal paralysis, fatigue and prolonged convalescence. The key pathogenic factor in postoperative morbidity, excluding failures of surgical and anaesthetic technique, is the surgical stress response with subsequent increased demands on organ function. These changes in organ function are thought to be mediated by trauma-induced endocrine metabolic changes and activation of several biological cascade systems (cytokines, complement, arachidonic acid metabolites, nitric oxide, free oxygen radicals, etc). To understand postoperative morbidity it is therefore necessary to understand the pathophysiological role of the various components of the surgical stress response and to determine if modification of such responses may improve surgical outcome. While no single technique or drug regimen has been shown to eliminate postoperative morbidity and mortality, multimodal interventions may lead to a major reduction in the undesirable sequelae of surgical injury with improved recovery and reduction in postoperative morbidity and overall costs.

Multimodal approach to control postoperative pathophysiology and rehabilitation.

Objective: To evaluate the effect of modifying perioperative care in noncardiac surgical patients on morbidity, mortality, and other outcome measures. Background: New approaches in pain control, introduction of techniques that reduce the perioperative stress response, and the more frequent use of minimal invasive surgical access have been introduced over the past decade. The impact of these interventions, either alone or in combination, on perioperative outcome was evaluated. Methods: We searched Medline for the period of 1980 to the present using the key terms fast track surgery, accelerated care programs, postoperative complications and preoperative patient preparation; and we examined and discussed the articles that were identified to include in this review. This information was supplemented with our own research on the mediators of the stress response in surgical patients, the use of epidural anesthesia in elective operations, and pilot studies of fast track surgical procedures using the multimodality approach. Results: The introduction of newer approaches to perioperative care has reduced both morbidity and mortality in surgical patients. In the future, most elective operations will become day surgical procedures or require only 1 to 2 days of postoperative hospitalization. Reorganization of the perioperative team (anesthesiologists, surgeons, nurses, and physical therapists) will be essential to achieve successful fast track surgical programs. Conclusions: Understanding perioperative pathophysiology and implementation of care regimes to reduce the stress of an operation, will continue to accelerate rehabilitation associated with decreased hospitalization and increased satisfaction and safety after discharge. Developments and improvements of multimodal interventions within the context of "fast track" surgery programs represents the major challenge for the medical professionals working to achieve a "pain and risk free" perioperative course.

Multimodal strategies to improve surgical outcome.

Multimodal Approach to Control Postoperative Pathophysiology and Rehabilitation

Background The STOP-Bang questionnaire is used to screen patients for obstructive sleep apnoea (OSA). We evaluated the association between STOP-Bang scores and the probability of OSA. Methods After Institutional Review Board approval, patients who visited the preoperative clinics for a scheduled inpatient surgery were approached for informed consent. Patients answered STOP questionnaire and underwent either laboratory or portable polysomnography (PSG). PSG recordings were scored manually. The BMI, age, neck circumference, and gender (Bang) were documented. Over 4 yr, 6369 patients were approached and 1312 (20.6%) consented. Of them, 930 completed PSG, and 746 patients with complete data on PSG and STOP-Bang questionnaire were included for data analysis. Results The median age of 746 patients was 60 yr, 49% males, BMI 30 kg m−2, and neck circumference 39 cm. OSA was present in 68.4% with 29.9% mild, 20.5% moderate, and 18.0% severe OSA. For a STOP-Bang score of 5, the odds ratio (OR) for moderate/severe and severe OSA was 4.8 and 10.4, respectively. For STOP-Bang 6, the OR for moderate/severe and severe OSA was 6.3 and 11.6, respectively. For STOP-Bang 7 and 8, the OR for moderate/severe and severe OSA was 6.9 and 14.9, respectively. The predicted probabilities for moderate/severe OSA increased from 0.36 to 0.60 as the STOP-Bang score increased from 3 to 7 and 8. Conclusions In the surgical population, a STOP-Bang score of 5–8 identified patients with high probability of moderate/severe OSA. The STOP-Bang score can help the healthcare team to stratify patients for unrecognized OSA, practice perioperative precautions, or triage patients for diagnosis and treatment.

/pdf/high-stop-bang-score-indicates-a-high-probability-of-3hwtvfbgb3.pdf

High STOP-Bang score indicates a high probability of obstructive sleep apnoea

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 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.

https://www.mayoclinicproceedings.org/article/S0025-6196(11)62108-3/pdf

Postoperative complications in patients with obstructive sleep apnea syndrome undergoing hip or knee replacement: a case-control study

Ten patients undergoing major abdominal surgery under general anaesthesia were monitored with a pulse oximeter, electroencephalogram, electromyogram, electrocardiogram and eye and hand movement sensors two nights before and three nights after surgery. Episodic hypoxaemic events were increased significantly after surgery (P

Late postoperative nocturnal episodic hypoxaemia and associated sleep pattern

Unexpected deaths still occur following major surgical procedures. The cause is often unknown but may be cardiac or thromboembolic in nature. Postoperative ischaemia, infarction and sudden cardiac death may be triggered by episodic or constant arterial hypoxaemia, which increases during the night. This study examined the circadian variation of sudden unexpected death following abdominal surgery between 1985 and 1989 inclusive. Deaths were divided into those occurring during the day (08.00-16.00 hours), evening (16.00-24.00 hours) and night (24.00-08.00 hours). Twenty-three deaths were considered to have been totally unexpected. Of 16 such patients undergoing autopsy, pulmonary embolism was the cause of death in five. In the remaining 11 patients, death occurred at night in eight (P < 0.005). Five of the seven patients without an autopsy died at night (P < 0.04); overall, 13 of 18 unexpected deaths occurred at night-time. These results suggest a need for further studies of sleep- and respiration-related effects on postoperative nocturnal cardiac function. The efficacy of monitoring during this apparent high-risk period should be evaluated.

Circadian variation in unexpected postoperative death.

As constant hypoxaemia itself may trigger development of apnoea and periodic breathing, we have studied the effect of oxygen therapy on the occurrence of late postoperative episodic hypoxaemia. Thirty-five patients without cardiopulmonary disease and undergoing elective total hip replacement were monitored with a pulse oximeter on the second night after operation (23:00 to 07:00). receiving either 21% or 37% oxygen by face mask in a randomized double-blind design. Mean oxygen saturation was greater in the group receiving 37% oxygen than in those having 21% oxygen (96% vs 92%, P s = −0.62, P

Effect of oxygen therapy on late postoperative episodic and constant hypoxaemia

As constant hypoxaemia itself may trigger development of apnoea and periodic breathing, we have studied the effect of oxygen therapy on the occurrence of late postoperative episodic hypoxaemia. Thirty-five patients without cardiopulmonary disease and undergoing elective total hip replacement were monitored with a pulse oximeter on the second night after operation (23:00 to 07:00), receiving either 21% or 37% oxygen by face mask in a randomized double-blind design. Mean oxygen saturation was greater in the group receiving 37% oxygen than in those having 21% oxygen (96% vs 92%, P less than 0.01). There was a weak correlation between mean oxygen saturation and the total number of hypoxaemic episodes (rs = -0.62, P less than 0.001), explained partly by the calculated (non-mechanistic) reduction in mean saturation by the episodes of hypoxaemia. There was no significant difference between the groups in the total number of sudden decreases in oxygen saturation, the duration of the events or number of patients with events to more or less than 80% oxygen saturation, although there was a trend towards fewer patients having events to less than 80% in the 37% oxygen group (nine of 17 patients vs five of 18 patients (ns); 95% confidence limits of median difference: -6 to 56%). We conclude that postoperative oxygen therapy with 37% oxygen by face mask increases mean oxygen saturation, but does not influence the basic mechanism leading to episodic hypoxaemia.

M.H. Pedersen

Papers

Late postoperative nocturnal episodic hypoxaemia and associated sleep pattern

Circadian variation in unexpected postoperative death.

Effect of oxygen therapy on late postoperative episodic and constant hypoxaemia

Effect of Oxygen Therapy on Late Postoperative Episodic and Constant Hypoxemia