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Background The outcomes of emergent noncardiac, nonintracranial surgery in patients with previous stroke remain unknown. Methods All emergency surgeries performed in Denmark (2005 to 2011) were analyzed according to time elapsed between previous ischemic stroke and surgery. The risks of 30-day mortality and major adverse cardiovascular events were estimated as odds ratios (ORs) and 95% CIs using adjusted logistic regression models in a priori defined groups (reference was no previous stroke). In patients undergoing surgery immediately (within 1 to 3 days) or early after stroke (within 4 to 14 days), propensity-score matching was performed. Results Of 146,694 nonvascular surgeries (composing 98% of all emergency surgeries), 5.3% had previous stroke (mean age, 75 yr [SD = 13]; 53% women, 50% major orthopedic surgery). Antithrombotic treatment and atrial fibrillation were more frequent and general anesthesia less frequent in patients with previous stroke (all P < 0.001). Risks of major adverse cardiovascular events and mortality were high for patients with stroke less than 3 months (20.7 and 16.4% events; OR = 4.71 [95% CI, 4.18 to 5.32] and 1.65 [95% CI, 1.45 to 1.88]), and remained increased for stroke within 3 to 9 months (10.3 and 12.3%; OR = 1.93 [95% CI, 1.55 to 2.40] and 1.20 [95% CI, 0.98 to 1.47]) and stroke more than 9 months (8.8 and 11.7%; OR = 1.62 [95% CI, 1.43 to 1.84] and 1.20 [95% CI, 1.08 to 1.34]) compared with no previous stroke (2.3 and 4.8% events). Major adverse cardiovascular events were significantly lower in 323 patients undergoing immediate surgery (21%) compared with 323 successfully propensity-matched early surgery patients (29%; P = 0.029). Conclusions Adverse cardiovascular outcomes and mortality were greatly increased among patients with recent stroke. However, events were higher 4 to 14 days after stroke compared with 1 to 3 days after stroke.

Background The isolated forearm technique allows assessment of consciousness of the external world (connected consciousness) through a verbal command to move the hand (of a tourniquet-isolated arm) during intended general anesthesia. Previous isolated forearm technique data suggest that the incidence of connected consciousness may approach 37% after a noxious stimulus. The authors conducted an international, multicenter, pragmatic study to establish the incidence of isolated forearm technique responsiveness after intubation in routine practice. Methods Two hundred sixty adult patients were recruited at six sites into a prospective cohort study of the isolated forearm technique after intubation. Demographic, anesthetic, and intubation data, plus postoperative questionnaires, were collected. Univariate statistics, followed by bivariate logistic regression models for age plus variable, were conducted. Results The incidence of isolated forearm technique responsiveness after intubation was 4.6% (12/260); 5 of 12 responders reported pain through a second hand squeeze. Responders were younger than nonresponders (39 ± 17 vs. 51 ± 16 yr old; P = 0.01) with more frequent signs of sympathetic activation (50% vs. 2.4%; P = 0.03). No participant had explicit recall of intraoperative events when questioned after surgery (n = 253). Across groups, depth of anesthesia monitoring values showed a wide range; however, values were higher for responders before (54 ± 20 vs. 42 ± 14; P = 0.02) and after (52 ± 16 vs. 43 ± 16; P = 0.02) intubation. In patients not receiving total intravenous anesthesia, exposure to volatile anesthetics before intubation reduced the odds of responding (odds ratio, 0.2 [0.1 to 0.8]; P = 0.02) after adjustment for age. Conclusions Intraoperative connected consciousness occurred frequently, although the rate is up to 10-times lower than anticipated. This should be considered a conservative estimate of intraoperative connected consciousness.

Background The effect on cardiovascular outcomes of withholding angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers in chronic users before noncardiac surgery is unknown. Methods In this international prospective cohort study, the authors analyzed data from 14,687 patients (including 4,802 angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker users) at least 45 yr old who had in-patient noncardiac surgery from 2007 to 2011. Using multivariable regression models, the authors studied the relationship between withholding angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers and a primary composite outcome of all-cause death, stroke, or myocardial injury after noncardiac surgery at 30 days, with intraoperative and postoperative clinically important hypotension as secondary outcomes. Results Compared to patients who continued their angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers, the 1,245 (26%) angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker users who withheld their angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers in the 24 h before surgery were less likely to suffer the primary composite outcome of all-cause death, stroke, or myocardial injury (150/1,245 [12.0%] vs. 459/3,557 [12.9%]; adjusted relative risk, 0.82; 95% CI, 0.70 to 0.96; P = 0.01) and intraoperative hypotension (adjusted relative risk, 0.80; 95% CI, 0.72 to 0.93; P < 0.001). The risk of postoperative hypotension was similar between the two groups (adjusted relative risk, 0.92; 95% CI, 0.77 to 1.10; P = 0.36). Results were consistent across the range of preoperative blood pressures. The practice of withholding angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers was only modestly correlated with patient characteristics and the type and timing of surgery. Conclusions Withholding angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers before major noncardiac surgery was associated with a lower risk of death and postoperative vascular events. A large randomized trial is needed to confirm this finding. In the interim, clinicians should consider recommending that patients withhold angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers 24 h before surgery.

BACKGROUND: Prior data from the isolated forearm technique (IFT) following noxious stimuli suggest that the incidence of response to command may approach 40% under anesthesia 1,2 . We conducted an international, multicenter, pragmatic study of the IFT to establish the incidence of responsiveness following intubation in current practice (NCT02248623). Methods: Following IRB approval at six sites, 260 adult patients were recruited from six centers into a prospective observational cohort study of the IFT during induction of anesthesia . Univariate comparisons were made with Student’s t­test assuming equal variances, and Pearson’s χ2 test. Bivariate models were constructed using logistic regression . RESULTS: The incidence of IFT responsiveness following intubation was 4 .6% (12/260). Responders were younger than nonresponders ([mean±standard deviation] 39±17 vs . 51±16 years old; p=0 .009) and had a higher incidence of observer rated signs of distress (50% vs . 2 .4%; p=0 .027) with 5 out of 12 responders reporting pain through a second hand squeeze . No subject reported explicit recall of intraoperative events when questioned after surgery (n=253) . Depth of anesthesia monitoring values showed a wide range in both groups; however mean values were higher for responders before (53±19 vs . 42±14; p=0 .032) and after (55±24 vs . 43±16; p=0 .032) intubation . In patients not receiving total intravenous anesthesia, exposure to volatile anesthetics prior to intubation reduced the odds of responding (OR 0 .2 (0 .1 - 0 .8); p=0 .022) following adjustment for age . CONCLUSIONS: An incidence rate of 4 .6% suggests that intraoperative connected consciousness may occur frequently but this rate is lower than predicted from previous studies . Larger studies are required to identify risk factors for, and long-term consequences of, IFT responsiveness. REFERENCES: 1 . Sanders RD, Tononi G, Laureys S, Sleigh JW . Unresponsiveness ≠ Unconsciousness Anesthesiology. 2012;116:946­959. 2 . Schneider G, Wagner K, Reeker W, Hanel F, Werner C, Kochs E. Bispectral Index (BIS) may not predict awareness reaction to intubation in surgical patients . J Neurosurg Anesthesiol . Jan 2002;14(1):7-11

BACKGROUND: Statins reduce risk from coronary artery bypass graft (CABG) surgery, but the influence of angiotensin-converting enzyme inhibitors, alpha-2 adrenergic agonists, calcium channel blockers and beta-blockers is less clear. OBJECTIVES: We investigated the association of each of these drugs with perioperative risk, accounting for different confounders, and evaluated the class, dose-response and long-term protective effect of statins. DESIGN: A retrospective analysis of observational data. SETTING: United Kingdom. PATIENTS: Sixteen thousand one hundred and ninety-two patients who underwent CABG surgery during the period 01 January 2004 to 31 December 2013 and contributed data to Primary Care Clinical Practice Research Datalink. EXPOSURE VARIABLES: Cardiovascular drugs. OUTCOME MEASURE: Perioperative mortality within 30 days of surgery. STATISTICAL ANALYSIS: Five multivariable logistic regression models and a further Cox regression model were used to account for preexisting cardiovascular and other comorbidities along with lifestyle factors such as BMI, smoking and alcohol use. RESULTS: Exposure to statins was most prevalent (85.1% of patients), followed by beta-blockers (72.8%), angiotensin-converting enzyme inhibitors (60.5%), calcium channel blockers (42.8%) and alpha-2 adrenergic agonists (1.2%). The mortality rate was 0.8% in patients not prescribed statins and 0.4% in those on statins. Statins were associated with a statistically significant reduced perioperative mortality in all five logistic regression models with adjusted odds ratios (OR) (95% confidence interval, 95% CI) ranging from 0.26 (0.13 to 0.54) to 0.35 (0.18 to 0.67). Cox regression for perioperative mortality [adjusted hazard ratio (95% CI) 0.40 (0.20 to 0.80)] and 6-month mortality [adjusted hazard ratio (95% CI) 0.63 (0.42 to 0.92)] produced similar results. Of the statin doses tested, only simvastatin 40?mg exerted protective effects. The other cardiovascular drugs lacked consistent effects across models. CONCLUSION: Statins appear consistently protective against perioperative mortality from CABG surgery in multiple models, an effect not shared by the other cardiovascular drugs. Further data are needed on whether statins exert class and dose-response effects.

Randomised controlled trials (RCTs) are the gold standard for measuring the efficacy of any medical intervention. The present study assesses the implementation of the CONSORT statement in the top 11 anaesthesiology journals in 2011.We designed this study in order to determine how well authors in the top 11 ranked anaesthesiology journals follow the CONSORT statement's criteria.A retrospective cross-sectional data analysis.The study was performed at the RWTH Aachen University Hospital.Journals included Pain, Anesthesiology, British Journal of Anaesthesia, Regional Anesthesia and Pain Medicine, European Journal of Pain, Anesthesia and Analgesia, Anaesthesia, Minerva Anestesiologica, Canadian Journal of Anesthesia, Journal of Neurosurgical Anesthesiology and the European Journal of Anaesthesiology.All articles in the online table of contents from the top 11 anaesthesiology journals according to the ISI Web of Knowledge were screened for RCTs published in 2011. The RCTs were assessed using the CONSORT checklist. We also analysed the correlation between the number of citations and the adherence to CONSORT items.We evaluated 319 RCTs and found that, more than ten years after the publication of the CONSORT statement, the RCTs satisfied a median of 60.0% of the CONSORT criteria. Only 72.1% of the articles presented clearly defined primary and secondary outcome parameters. The number of citations is only weakly associated with the fulfilment of the CONSORT statement (r = 0.023).Adherence to the CONSORT criteria remains low in top-ranked anaesthesiology journals. We found only a very weak correlation between the number of citations and fulfilment of the requirements of the CONSORT statement.

The aim of this article is to review recent behavioural and neuroimaging studies in anaesthesia and the vegetative state.These studies highlight possible dissociations between consciousness and responsiveness in both these states.We discuss future avenues of research in the field, in order to improve the detection of awareness during anaesthesia and the vegetative state using neuroimaging and neurophysiologic techniques.

Background: Data are lacking on the optimal scheduling of coronary artery bypass grafting (CABG) surgery after stroke. The authors investigated the preoperative predictors of adverse outcomes in patients undergoing CABG, with a focus on the importance of the time interval between prior stroke and CABG. Methods: The Hospital Episode Statistics database (April 2006–March 2010) was analyzed for elective admissions for CABG. Independent preoperative patient factors influencing length of stay, postoperative stroke, and mortality, were identified by logistic regression and presented as adjusted odds ratios (OR). Results: In all, 62,104 patients underwent CABG (1.8% mortality). Prior stroke influenced mortality (OR 2.20 [95% CI 1.47–3.29]), postoperative stroke (OR 1.99 [1.39–2.85]), and prolonged length of stay (OR 1.31 [1.11–1.56]). The time interval between stroke and CABG did not influence mortality or prolonged length of stay. However, a longer time interval between stroke and CABG surgery was associated with a small increase in risk of postoperative stroke (OR per month elapsed 1.02 [1.00–1.04]; P = 0.047). An interaction was evident between prior stroke and myocardial infarction for death (OR 5.50 [2.84–10.8], indicating the importance of the combination of comorbidities. Prominent effects on mortality were also exerted by liver disease (OR 20.8 [15.18–28.51]) and renal failure (OR 4.59 [3.85–5.46]). Conclusions: The authors found no evidence that more recent preoperative stroke predisposed patients undergoing CABG surgery to suffer postoperative stroke, death, or prolonged length of stay. The combination of prior stroke and myocardial infarction substantially increased perioperative risk.

The clinical applications of xenon for the neonate include both anaesthesia and neuroprotection. However, due to the limited natural availability of xenon, special equipment is required to administer and recapture the gas to develop xenon as a therapeutic agent.In order to test the xenon recirculating ventilator for the application of neuroprotection in a preclinical trial, our primary objective was to test the efficiency, reliability and safety of administering 50% xenon for 24 h in hypoxic ischaemic piglets.A prospective observational study.Institute for Women's Health, University College London, January 2008 to March 2008.Four anaesthetised male piglets, less than 24 h old, underwent a global hypoxic ischaemic insult for approximately 25 min prior to switching to the xenon recirculating ventilator.Between 2 and 26 h after hypoxic ischaemia, anaesthetised piglets were administered a mixture of 50% xenon, air, oxygen and isoflurane.The primary outcome measure was blood gas PaCO2 (kPa) and secondary outcome measure was xenon gas use (l h), over the 24-h duration of xenon administration.The xenon recirculating ventilator provided effective ventilation, automated control of xenon/air gas mixtures, and stable blood gas PaCO2 (4.5 to 6.3 kPa) for 24 h of ventilation with the xenon recirculating ventilator. Total xenon use was minimal at approximately 0.6 l h at a cost of approximatelyOV0556;8 h. Additional features included an isoflurane scavenger and bellows height alarm.Stable gas delivery to a piglet with minimal xenon loss and analogue circuitry made the xenon recirculating ventilator easy to use and it could be modified for other large animals and noble gas mixtures. The technologies, safety and efficiency of xenon delivery in this preclinical system have been taken forward in the development of neonatal ventilators for clinical use in phase II clinical trials for xenon-augmented hypothermia and for xenon anaesthesia.

Background Neuroapoptosis is induced by the administration of anesthetic agents to the young. As alpha2 adrenoceptor signaling plays a trophic role during development and is neuroprotective in several settings of neuronal injury, the authors investigated whether dexmedetomidine could provide functional protection against isoflurane-induced injury. Methods Isoflurane-induced injury was provoked in organotypic hippocampal slice cultures in vitro or in vivo in postnatal day 7 rats by a 6-h exposure to 0.75% isoflurane with or without dexmedetomidine. In vivo, the alpha2 adrenoceptor antagonist atipamezole was used to identify if dexmedetomidine neuroprotection involved alpha2 adrenoceptor activation. The gamma-amino-butyric-acid type A antagonist, gabazine, was also added to the organotypic hippocampal slice cultures in the presence of isoflurane. Apoptosis was assessed using cleaved caspase-3 immunohistochemistry. Cognitive function was assessed in vivo on postnatal day 40 using fear conditioning. Results In vivo dexmedetomidine dose-dependently prevented isoflurane-induced injury in the hippocampus, thalamus, and cortex; this neuroprotection was attenuated by treatment with atipamezole. Although anesthetic treatment did not affect the acquisition of short-term memory, isoflurane did induce long-term memory impairment. This neurocognitive deficit was prevented by administration of dexmedetomidine, which also inhibited isoflurane-induced caspase-3 expression in organotypic hippocampal slice cultures in vitro; however, gabazine did not modify this neuroapoptosis. Conclusion Dexmedetomidine attenuates isoflurane-induced injury in the developing brain, providing neurocognitive protection. Isoflurane-induced injury in vitro appears to be independent of activation of the gamma-amino-butyric-acid type A receptor. If isoflurane-induced neuroapoptosis proves to be a clinical problem, administration of dexmedetomidine may be an important adjunct to prevent isoflurane-induced neurotoxicity.

Background Perinatal hypoxia-ischemia causes significant morbidity and mortality. Xenon and sevoflurane may be used as inhalational analgesics for labor. Therefore, the authors investigated the potential application of these agents independently and in combination to attenuate perinatal injury. Methods Oxygen-glucose deprivation injury was induced in pure neuronal or neuronal-glial cocultures 24 h after preconditioning with xenon and/or sevoflurane. Cell death was assessed by lactate dehydrogenase release or staining with annexin V-propidium iodide. The mediating role of phosphoinositide-3-kinase signaling in putative protection was assessed using wortmannin, its cognate antagonist. In separate in vivo experiments, perinatal asphyxia was induced 4 hours after preconditioning with analgesic doses alone and in combination; infarct size was assessed 7 days later, and neuromotor function was evaluated at 30 days in separate cohorts. The role of phosphorylated cyclic adenosine monophosphate response element binding protein in the preconditioning was assessed by immunoblotting. Results Both anesthetics preconditioned against oxygen-glucose deprivation in vitro alone and in combination. The combination increased cellular viability via phosphoinositide-3- kinase signaling. In in vivo studies, xenon (75%) and sevoflurane (1.5%) alone as well as in combination (20% xenon and 0.75% sevoflurane) reduced infarct size in a model of neonatal asphyxia. Preconditioning with xenon and the combination of xenon and sevoflurane resulted in long-term functional neuroprotection associated with enhanced phosphorylated cyclic adenosine monophosphate response element binding protein signaling. Conclusions Preconditioning with xenon and sevoflurane provided long-lasting neuroprotection in a perinatal hypoxic-ischemic model and may represent a viable method to preempt neuronal injury after an unpredictable asphyxial event in the perinatal period.

Nitrous oxide is the longest serving member of the anesthesiologist’s pharmacologic armamentarium but remains a source of controversy because of fears over its adverse effects. Recently, the Evaluation of Nitrous oxide In a Gas Mixture for Anaesthesia (ENIGMA) trial reported that nitrous oxide use increases postoperative complications; further preclinical reports have suggested that nitrous oxide may contribute to neurocognitive dysfunction in the young and elderly. Therefore, nitrous oxide’s longevity in anesthetic practice is under threat. In this article, the authors discuss the evidence for the putative toxicity of nitrous oxide, from either patient or occupational exposure, within the context of the mechanism of nitrous oxide’s action. Although it would seem prudent to avoid nitrous oxide in certain vulnerable populations, current evidence in support of a more widespread proscription from clinical practice is unconvincing. NITROUS oxide has been used in clinical anesthetic practice for more than 150 yr, and its longevity should be considered within the context of all the major advances in anesthetic practice over that time. Fifty years ago, concerns were expressed about nitrous oxide’s toxicity after anesthesia. 1 This report was followed 10 yr later with concerns

The anesthetic properties of xenon have been known for more than 50 yr, and the safety and efficacy of xenon inhalational anesthesia has been demonstrated in several recent clinical studies. In addition, xenon demonstrates many favorable pharmacodynamic and pharmacokinetic properties, which could be used in certain niche clinical settings such as cardiopulmonary bypass. This inert gas is capable of interacting with a variety of molecular targets, and some of them are also modulated in anesthesia-relevant brain regions. Besides these anesthetic and analgesic effects, xenon has been shown to exert substantial organoprotective properties, especially in the brain and the heart. Several experimental studies have demonstrated a reduction in cerebral and myocardial infarction after xenon application. Whether this translates to a clinical benefit must be determined because preservation of myocardial and cerebral function may outweigh the significant cost of xenon administration. Clinical trials to assess the impact of xenon in settings with a high probability of injury such as cardiopulmonary bypass and neonatal asphyxia should be designed and underpinned with investigation of the molecular targets that transduce these effects.

OBJECTIVE Epinephrine given during closed-chest resuscitation increases blood flow across the coronary and cerebral circuits. However, epinephrine worsens reperfusion arrhythmias and intensifies postresuscitation myocardial dysfunction. We investigated whether cariporide-a selective sodium-hydrogen exchanger isoform-1 inhibitor-could ameliorate such adverse effects without diminishing its vasopressor actions. DESIGN Randomized animal study. SETTING University-based animal laboratory. SUBJECTS Twenty-four anesthetized male domestic pigs (29-43 kg). INTERVENTIONS Ventricular fibrillation was electrically induced and left untreated for 8 mins. Pigs were randomized to receive after 2 mins of chest compression a 3 mg/kg bolus of cariporide (n = 8), a 0.02 mg/kg bolus of epinephrine (n = 8), or a combination of cariporide and epinephrine (n = 8). Additional doses of epinephrine were given if the coronary perfusion pressure decreased below 15 mm Hg. Successfully resuscitated pigs were observed for 72 hrs. MEASUREMENTS AND MAIN RESULTS The averaged coronary perfusion pressure was higher in the epinephrine (34 +/- 11 mm Hg, p = .001) and cariporide/epinephrine (35 +/- 10 mm Hg, p < .001) groups compared with the cariporide group (15 +/- 6 mm Hg). All pigs in the epinephrine and cariporide/epinephrine groups but only six in the cariporide group were successfully resuscitated and survived 72 hrs. During the immediate postresuscitation period, four of eight pigs in the epinephrine group had episodes of recurrent ventricular fibrillation or pulseless ventricular tachycardia requiring additional electrical shocks (7.0 +/- 6.4) but none in the cariporide and cariporide/epinephrine groups (chi-square, p = .008). Myocardial dysfunction occurred early after return of spontaneous circulation but only in the epinephrine group. CONCLUSIONS The combined administration of cariporide and epinephrine prompted adequate pressor effects during chest compression and facilitated reestablishment of cardiac activity without episodes of recurrent ventricular fibrillation or transient myocardial dysfunction as with epinephrine alone.

See related article, page 38. Perioperative stroke increases the risk of mortality by up to 10-fold after cardiac and noncardiac surgery.1–6 In addition to increased disability experienced by the patient, the burden of perioperative stroke significantly impacts healthcare costs.2,7 Given the significant consequences imposed by perioperative stroke, it is fortunate that its incidence remains below 10%, even after more complicated cardiac valvular surgery.2 However, concern has arisen that the burden of perioperative stroke (defined as occurring within 30 days of operation) will increase as a growing number of elderly patients with significant comorbidities are offered cardiac surgery.8 In this issue of Stroke , Merie and colleagues approach this important question using a Danish administrative database of 25 159 patients having undergone coronary artery bypass grafting surgery.1 Their findings challenge the generally accepted notion that elderly patients (age >70 years) should be considered at increased risk of perioperative stroke, and as a result, perhaps be denied surgery.8 In contrast to advanced age, the authors emphasize the independent role of comorbidities, in particular previous stroke, in increasing the risk of perioperative stroke.1 This study also demonstrates the importance of considering a contemporary group of patients when determining perioperative risks. With the continued evolution of surgical and anesthetic techniques, perioperative risk may also have changed in recent times. Indeed, their analysis is important, as the traditional perioperative stroke data that they compare their own results with (such as Roach et al8) are more than 20 years old and may no longer adequately represent current surgical, anesthetic, or patient factors. Nonetheless, we must not downplay the …

OBJECTIVE: The authors review the general surgical complications of cardiopulmonary bypass, including newer procedures such as heart and lung transplantation, to identify patients at higher risk. SUMMARY BACKGROUND DATA: Although rare, the general surgical complications of cardiopulmonary bypass are associated with high mortality. The early identification of patients at increased risk for these complications may allow for earlier detection and treatment of these problems to reduce mortality. METHODS: A retrospective review was performed of 1831 patients undergoing cardiopulmonary bypass from 1991 to 1993. This was done to identify factors that significantly contributed to an increased risk of general surgical complications. RESULTS: Factors associated with an increased risk of general surgical complications included prolonged cardiopulmonary bypass (p < 0.005) and intensive care unit stay (p < 0.002), occurrence of arrhythmias (p < 0.001), use of inotropic agents (preoperatively or postoperatively p < 0.001), insertion of the intra-aortic balloon pump (preoperatively p < 0.005, postoperatively p < 0.001), use of steroids (p < 0.001), and prolonged ventilator support (p < 0.001). Multivariate analysis identified use of the intra-aortic balloon pump (p < 0.001) as the strongest predictor of the general surgical complications of cardiopulmonary bypass. A variety of factors not contributing significantly to an increased risk also were identified. CONCLUSIONS: Factors indicative of or contributing to periods of decreased end-organ perfusion appear to be significantly related to general surgical complications after cardiopulmonary bypass.

Approximately a quarter of a billion people undergo surgery every year hoping that the operation will alleviate symptoms, cure diseases, and improve quality-of-life. A concern has arisen that, despite the benefits of surgery, elderly patients might suffer neurological injury from surgery and general anaesthesia leading to persistent cognitive decline. However, many studies of postoperative cognition have had methodological weaknesses, including lack of suitable control groups, dissociation of cognitive outcomes from surgical outcomes, sub-optimal statistical techniques, and absence of longitudinal preoperative cognitive assessments. Emerging evidence suggests that after early cognitive decline, most patients return to their preoperative cognitive trajectories within 3 months of surgery; some even experience subsequent cognitive improvement. In this review, we summarize the scientific literature on perioperative cognition. We propose that the most important determinants of the postoperative cognitive trajectory are the preoperative cognitive trajectory, the success of the surgery, and events in the perioperative period. Postoperative complications, ongoing inflammation, and chronic pain are probably modifiable risk factors for persistent postoperative cognitive decline. When surgery is successful with minimal perioperative physiological perturbations, elderly patients can expect cognition to follow its preoperative course. Furthermore, when surgery alleviates symptoms and enhances quality-of-life, postoperative cognitive improvement is a possible and desirable outcome.