Postoperative intracranial haemorrhage: a review

Postoperative haemorrhage (POH) is one of the most serious complications of any cranial neurosurgical procedure and is associated with significant morbidity and mortality. The relative paucity of work investigating this postoperative complication prompted us to undertake a review of the literature, focussing on demographic, clinical, and surgical risk factors. A literature search was undertaken using Ovid MEDLINE (1950–2009) using keywords including craniectomy, craniotomy, neurosurgery, intracranial, reoperation, repeat craniotomy, postoperative, haemorrhage, haematoma, and bleeding. The rates of POH following intracranial procedures reported in the literature vary greatly, and meaningful comparison is difficult. We defined postoperative haemorrhage as that following craniotomy, which is clinically significant and requires surgical evacuation. Risk factors include pre-existing medical comorbidities including hypertension, coagulopathies and haematological abnormalities, intraoperative hypertension and blood loss, certain lesion pathologies including tumours, chronic subdural haematomas, and deficiencies in haemostasis. We conclude by providing recommendations for clinical practice based on the literature reviewed to aid clinicians in the detection and avoidance of POH.     

Postoperative complications in patients with obstructive sleep apnea: a meta-analysis

Study ObjectiveTo determine whether a diagnosis of obstructive sleep apnea (OSA) imparts an increased risk of postoperative respiratory failure, cardiac events, and intensive care unit (ICU) transfer than patients with no OSA diagnosis.DesignSystematic review and meta-analysis.SettingAcademic Veterans Affairs Medical Center.MeasurementsPubMed, EMBASE, CINAHL, and ISI Web of Knowledge databases were searched through April 2013 for studies that examined the relationship between OSA and postoperative respiratory and cardiac complications among adults. Either fixed or random-effects models were used to calculate the pooled risk estimates. Sensitivity analysis was conducted to examine the robustness of pooled outcomes.Main ResultsSeventeen studies with a total of 7,162 patients were included. Overall, OSA was associated with significant increase in risk of respiratory failure [odds ratio (OR) 2.42; 95% confidence intervals (CI) 1.53 - 3.84; P = 0.0002] and cardiac events postoperatively (OR = 1.63; 95% CI 1.16 - 2.29; P = 0.005). Heterogeneity was low for these outcomes (I² = 5% and 0%, respectively). ICU transfer occurred also more frequently in patients with OSA (OR 2.46; 95% CI 1.29 - 4.68; P = 0.006). These results did not materially change in the sensitivity analyses according to various inclusion criteria.ConclusionsSurgical patients with OSA are at increased risk of postoperative respiratory failure, cardiac events, and ICU transfer.     

Postoperative sore throat: a systematic review

Postoperative sore throat has a reported incidence of up to 62% following general anaesthesia. In adults undergoing tracheal intubation, female sex, younger age, pre‐existing lung disease, prolonged duration of anaesthesia and the presence of a blood‐stained tracheal tube on extubation are associated with the greatest risk. Tracheal intubation without neuromuscular blockade, use of double‐lumen tubes, as well as high tracheal tube cuff pressures may also increase the risk of postoperative sore throat. The expertise of the anaesthetist performing tracheal intubation appears to have no influence on the incidence in adults, although it may in children. In adults, the i‐gel^™ supraglottic airway device results in a lower incidence of postoperative sore throat. Cuffed supraglottic airway devices should be inflated sufficiently to obtain an adequate seal and intracuff pressure should be monitored. Children with respiratory tract disease are at increased risk. The use of supraglottic airway devices, oral, rather than nasal, tracheal intubation and cuffed, rather than uncuffed, tracheal tubes have benefit in reducing the incidence of postoperative sore throat in children. Limiting both tracheal tube and supraglottic airway device cuff pressure may also reduce the incidence.     

Postoperative respiratory arrhythmias: incidence and measurement

BACKGROUND: Postoperative respiratory disturbances may be the result either of depression of respiratory drive, or alteration of respiratory pattern. METHODS: Using an inductance plethysmograph, we continuously recorded the breathing in 52 patients for 4 h after major thoracic, abdominal, and body surface surgery. The ventilatory response to hypercapnia was measured preoperatively, and at the start and end of the observation period. RESULTS: From a variety of statistical measures of respiratory depression, it was found that the occurrence of apnoeas (breath times >10 s), did not correlate with measures of respiratory drive, or with dose or route of administration of opioid, site of surgery, pain, or drowsiness. Instead, the incidence of apnoeas correlated most closely with measures of respiratory pattern (standard deviation of breath times (r=0.72), the mean breath time (r=0.63), approximate entropy of the breath times (r= -0.32)). Twenty-nine percent of patients had some breath times (Ttot) longer than 20 s. CONCLUSION: We would conclude that changes in respiratory pattern are not closely correlated with changes in traditional measures of respiratory drive.     

Postoperative metabolic stress: interventional strategies

More and more evidence accumulates suggesting that the reversal of the catabolic responses to surgery is associated with better outcome. The potential for anesthesiologists to be involved in altering outcome by simply preserving a normal blood glucose, providing optimal pain control and perioperative feeding is tremendous.     

Postoperative hypoxaemia: mechanisms and time course

Postoperative hypoxaemia results predominantly from two mechanisms. Gas exchange is impaired during anaesthesia as a result of reduced tone in the muscles of the chest wall and probably alterations in bronchomotor and vascular tone, and the resulting changes persist into the postoperative period. In addition, there is an abnormality of control of breathing, which results in episodic obstructive apnoea. These episodes continue for several days after operation and are related to sleep pattern and analgesic administration, although the precise effects of different analgesic regimens have not been evaluated. Oxygen administration is effect in reducing the degree of hypoxaemia.     

Sleep apnea and hypertension: pathophysiologic mechanisms.

This article reviews the pathophysiology of hypertension (HTN) in obstructive sleep apnea (OSA). The article is divided into 3 sections. The first section describes epidemiologic studies of the relationship of sleep-related breathing disorders, including OSA, to HTN and argues that OSA contributes to the genesis of HTN. The second section describes the known immediate physiologic consequences of 3 components of OSA that may contribute to the genesis of persistent systemic HTN. The 3 components are (1) the large negative intrathoracic pressure changes associated with OSA, (2) intermittent hypoxemia, and (3) arousal from sleep. The last section reviews current physiologic models of essential HTN genesis and attempts to integrate them with the suspected HTN-generating aspects of OSA. In its summary, the authors conclude that OSA contributes to the genesis of HTN and advise physicians not to ignore the contribution of frequently comorbid non-OSA factors, such as obesity, to the genesis of OSA-related HTN.     

Postoperative acute refractory right ventricular failure: incidence, pathogenesis, management and prognosis

Isolated acute refractory right ventricular failure is extremely uncommon. There are greater prospects of seeing a right dominant biventricular failure, as the two ventricular chambers are contiguous. The overall clinical spectrum is determined by the relative ischemic involvement of the right or left ventricle. The postoperative acute refractory right ventricular failure that develops after cardiotomy, heart transplant, or during a left ventricular assist device support, may have somewhat dissimilar elements of origin, but the resultant clinical picture and the management are essentially similar. In this collective review, the authors have summarized the incidence, pathogenesis, management and prognosis of postoperative acute refractory right ventricular failure, in adult cardiac surgical practice. The incidence of post-cardiotomy acute refractory right ventricular failure ranges from 0.04 to 0.1%. Acute refractory right ventricular failure has also been reported in 2-3% patients after a heart transplant and in almost 20-30% patients who receive a left ventricular assist device support. The main contributor to this problem is a disproportionate ischemic involvement of the right ventricle. Other pertinent contributors to this problem are pulmonary hypertension and an altered interventricular balance. The latter component is predominant in recipients of a left ventricular assist device support. Postoperative acute refractory right ventricular failure has been successfully managed with conventional pulmonary vasodilators, mechanical support with a pulmonary artery balloon pump, a right ventricular assist device, or cavopulmonary diversion. Unfortunately, the reported initial salvage rate is only 25-30%. This problem is often underestimated. Support measures are often started late or terminated prematurely. These factors have contributed to a poor initial salvage rate in this group of patients.     

Nausea, vomiting, and hiccups: a review of mechanisms and treatment

Nausea, vomiting, and hiccups are troubling complications associated with sedation and general anesthesia. This article will review the basic pathophysiology of these events and current recommendations for their prevention and management.     

Metabolic bariatric surgery as a treatment for obstructive sleep apnea hypopnea syndrome: review of the literature and potential mechanisms

Obstructive sleep apnea hypopnea syndrome (OSAHS) is closely related to obesity and can cause multiple organs and systems damage. Metabolic bariatric surgery (MBS) is presently the only long-term effective treatment and an important strategy for severely obese population, which also provides a novel therapeutic for obese patients with OSAHS, especially in patients with poor continuous positive air pressure (CPAP) adherence. To date, the resolution mechanism of OSAHS in obese patients after MBS has not been fully clarified. In addition, there is no specific metabolic bariatric surgical treatment of OSAHS guidelines. Therefore, this review provides an update on the relationship between OSAHS and MBS for highlighting the importance of weight loss strategies for obese patients with OSAHS.     

Postoperative systemic inflammatory dysregulation and corticosteroids: a narrative review

In some patients, the inflammatory-immune response to surgical injury progresses to a harmful, dysregulated state. We posit that postoperative systemic inflammatory dysregulation forms part of a pathophysiological response to surgical injury that places patients at increased risk of complications and subsequently prolongs hospital stay. In this narrative review, we have outlined the evolution, measurement and prediction of postoperative systemic inflammatory dysregulation, distinguishing it from a healthy and self-limiting host response. We reviewed the actions of glucocorticoids and the potential for heterogeneous responses to peri-operative corticosteroid supplementation. We have then appraised the evidence highlighting the safety of corticosteroid supplementation, and the potential benefits of high/repeated doses to reduce the risks of major complications and death. Finally, we addressed how clinical trials in the future should target patients at higher risk of peri-operative inflammatory complications, whereby corticosteroid regimes should be tailored to modify not only the a priori risk, but also further adjusted in response to markers of an evolving pathophysiological response.