Cognitive and functional competence after anaesthesia in patients aged over 60: controlled trial of general and regional anaesthesia for elective hip or knee replacement

Postoperative cognitive disorders and delirium in gynecologic surgery: Which surgery and anesthetic techniques to use to reduce the risk?

Despite their general good health, an increasing proportion of elderly individuals require surgery due to an increase in average lifespan. However, because of their increased vulnerability, these patients need to be handled carefully to make sure that surgery does not cause more harm than good. Age-related postoperative cognitive disorders (POCD) and postoperative delirium (POD), two serious consequences that are marked by adverse neuropsychologic alterations after surgery, are particularly dangerous for the elderly. In the context of gynecologic procedures, POCD and POD are examined in this narrative review. The main question is how to limit the rates of POCD and POD in older women undergoing gynecologic procedures by maximizing the risk-benefit balance. Three crucial endpoints are considered: (1) surgical procedures to lower the rates of POCD and POD, (2) anesthetic techniques to lessen the occurrence and (3) the identification of individuals at high risk for post-surgery cognitive impairments. Risks associated with laparoscopic gynecologic procedures include the Trendelenburg posture and CO2 exposure during pneumoperitoneum, despite statistical similarities in POD and POCD frequency between laparoscopic and laparotomy techniques. Numerous risk factors are associated with surgical interventions, such as blood loss, length of operation, and position holding, all of which reduce the chance of complications when they are minimized. In order to emphasize the essential role that anesthesia and surgery play in patient care, anesthesiologists are vital in making sure that anesthesia is given as sparingly and quickly as feasible. In addition, people who are genetically predisposed to POCD may be more susceptible to the disorder. The significance of a thorough strategy combining surgical and anesthetic concerns is highlighted in this article, in order to maximize results for senior patients having gynecologic surgery.

Substantial Improvement in Self-Reported Mental Health Following Total Hip Arthroplasty Occurs Independent of Anesthetic Technique

BACKGROUND

The influence of anesthetic type on mental health after total hip arthroplasty (THA) is poorly understood. Adverse effects of general anesthesia (GA) on cognition following major non-cardiac surgery are well known, but mental health following THA is less well-studied. We hypothesized that neuraxial anesthesia (NA) would provide favorable mental health profiles compared with GA after THA.

METHODS

Prospectively collected Patient-Reported Outcomes Measurement Information System-10 (PROMIS) Global Mental Health (GMH) scores at preoperative baseline, and 1, 3, and 6 months after THA were accessed on 4,353 patients in the Pulmonary Embolism Prevention After HiP and KneE Replacement (PEPPER) Trial (ClinicalTrials.gov: NCT02810704). Anesthesia was categorized as: general (GA), neuraxial (NA), and neuraxial with peripheral block (NAP). The GMH was assessed longitudinally and compared between groups.

RESULTS

Postoperative GMH improved (P < .05) over preoperative in every anesthetic group. Groups receiving NA had higher baseline GMH scores. Improvement in GMH was diminished after GA alone and plateaued after 1 month. Adding NA or peripheral nerve block to GA conferred additional benefit to GMH improvement.

CONCLUSIONS

Patient-perceived mental health improves significantly after THA regardless of anesthetic type. Patients who have higher baseline GMH scores more commonly received NA, likely due to nonsurgical care determinants; these differences in mental wellness persisted at follow-up. Adjunctive NA or peripheral nerve block favored GMH improvement, whereas solitary GA diminished GMH improvement, which plateaued after 1 month. Substantial mental health benefits of THA may overshadow subtle differences in GMH attributable to anesthetic type.

Postoperative Delirium and Cognitive Dysfunction after General and Regional Anesthesia: A Systematic Review and Meta-Analysis

Background: Perioperative disorders of neurocognitive function are a set of heterogeneous conditions, which include transient post-operative delirium (POD) and more prolonged post-operative cognitive dysfunction (POCD). Since the number of annually performed surgical procedures is growing, we should identify which type of anesthesia is safer for preserving neurocognitive function. The purpose of this study was to compare the effect of general anesthesia (GA) and regional anesthesia (RA) in patients undergoing surgical procedures under general anesthesia and regional anesthesia. Material and methods: We searched for randomized controlled studies, which studied post-operative cognitive outcomes after general and regional anesthesia in the adult patient population. Results: Thirteen articles with 3633 patients: the RA group consisted of 1823 patients, and the GA group of 1810 patients, who were selected for meta-analysis. The overall effect of the model shows no difference between these two groups in terms of risk for post-operative delirium. The result is insensitive to the exclusion of any study. There was no difference between RA and GA in terms of post-operative cognitive dysfunction. Conclusions: There was no statistically significant difference between GA and RA in the incidence of POD. There was no statistically significant difference in the incidence of POCD per-protocol analysis, psychomotor/attention tests (preoperative/baseline, post-operative), memory tests (postoperatively, follow up), mini-mental state examination score 24 h postoperatively, post-operative reaction time three months postoperatively, controlled oral word association test, and digit copying test. There were no differences in the incidence of POCD in general and regional anesthesia at one week postoperatively, three months postoperatively, or total events (one week or three months). The incidence of post-operative mortality also did not differ between two groups.

Postoperative Delirium and Postoperative Cognitive Dysfunction in Patients with Elective Hip or Knee Arthroplasty: A Narrative Review of the Literature

Postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) are common complications following total knee arthroplasty (TKA) and total hip arthroplasty (THA), affecting the length of hospital stay and increasing medical complications. Although many papers have been published on both conditions in this setting, no reviews have currently been written. Thus, the purpose of our study is to summarize the current literature and provide information about POD and POCD following elective THA or TKA. Our literature search was conducted in the electronic databases PubMed and the Cochrane library. We found that POD is a common complication following elective THA or TKA, with a median incidence of 14.8%. Major risk factors include older age, cognitive impairment, dementia, preoperative (pre-op) comorbidities, substance abuse, and surgery for fracture. Diagnosis can be achieved using tools such as the confusion assessment method (CAM), which is sensitive, specific, reliable, and easy to use, for the identification of POD. Treatment consists of risk stratification and the implementation of a multiple component prevention protocol. POCD has a median incidence of 19.3% at 1 week, and 10% at 3 months. Risk factors include older age, high BMI, and cognitive impairment. Treatment consists of reversing risk factors and implementing protocols in order to preserve physiological stability. POD and POCD are common and preventable complications following TKA and THA. Risk stratification and specific interventions can lower the incidence of both syndromes. Every physician involved in the care of such patients should be informed on every aspect of these conditions in order to provide the best care for their patients.

A Comparison of Neuraxial and General Anesthesia for Thirty-Day Postoperative Outcomes in United States Veterans Undergoing Total Knee Arthroplasty

BACKGROUND

The aim of this study is to investigate which anesthetic technique is superior on 30-day outcomes after primary total knee arthroplasty (TKA) in United States veteran patients. To our knowledge, this is the first account from the Veterans Health Administration comparing the effects of different anesthesia modalities in patients undergoing TKA.

METHODS

The Veterans Affairs Surgical Quality Improvement Program database was utilized to analyze patients undergoing primary TKA during the period of 2008-2015. Subjects were divided into 2 cohorts based on the method of surgical anesthesia used: general anesthesia or neuraxial anesthesia. Propensity score matching was utilized to avoid possible selection bias between the 2 cohorts when assessing patient demographics and comorbidities. The 2 groups were analyzed for 30-day postoperative complications, using multivariable logistic regression techniques to evaluate independent associations between anesthetic method and postoperative outcomes.

RESULTS

All Veterans Affairs patients undergoing primary TKA under general anesthesia (n = 32,363) and neuraxial anesthesia (n = 14,395) within the study period were included in this study. Following propensity score matching, multivariable analysis revealed significantly lower risks of cardiovascular (adjusted odds ratio [AOR] 0.74, 95% confidence interval [CI] 0.6-0.88, P < .001), respiratory (AOR 0.75, 95% CI 0.57-0.97, P = .03), and renal complications (AOR 0.62, 95% CI 0.4-0.9, P = .01) in patients receiving neuraxial anesthesia compared to those receiving general anesthesia. Neuraxial anesthesia was also associated with reduced hospital stay and lower odds of prolonged hospitalization (AOR 0.85, 95% CI 0.8-0.9, P < .001).

CONCLUSION

Veteran patients undergoing TKA under neuraxial anesthesia had reduced postoperative complications and decreased hospitalization stay compared to patients undergoing general anesthesia.

Comparative Effect of Local Anesthesia with Lidocaine 2% Versus Topical Anesthesia on Cognitive Function in Ophthalmic Surgery

Background

Multiple clinical trials targeted the assessment of cognitive function following local versus general anesthesia in patients undergoing ophthalmic surgery, but no previous clinical trials have focused on the effect of topical anesthesia on cognitive function.

Objectives

This study aimed to compare the effect of local anesthesia with lidocaine 2% versus topical anesthesia with Oxybuprocaine (benoxinate hydrochloride 0.4%) on cognitive function in patients undergoing elective cataract surgery.

Methods

This is a prospective randomized clinical trial carried out on 60 patients undergoing elective cataract surgery by phacoemulsification. Thirty patients received local anesthesia with lidocaine 2% and thirty patients received topical anesthesia with Oxybuprocaine (benoxinate hydrochloride 0.4%). Patients’ satisfaction was assessed postoperatively using the Iowa satisfaction with anesthesia scale (ISAS). Cognitive assessment for all patients was done preoperatively and 1 week postoperatively using paired-associate learning test (PALT) and category verbal fluency (VF) test (animal category).

Results

There was no statistically significant difference between local and topical anesthesia groups in the mean of responses to the 11 statements of ISAS (P = 0.071). Regarding cognitive assessment, there was a statistically significant postoperative decline in the local anesthesia group in both PALT scores (P = 0.005) and VF scores (P = 0.01). In the topical anesthesia group, there was no statistically significant difference between pre- and postoperative PALT scores (P = 0.326) or VF scores (P = 0.199).

Conclusions

Postoperative cognitive dysfunction following elective cataract surgeries under local anesthesia can be attributed to the effect of local anesthesia rather than the effect of surgery.

Cognitive function after surgery with regional or general anesthesia: A population-based study

INTRODUCTION

Our aim was to examine whether surgery with regional anesthesia (RA) is associated with accelerated long-term cognitive decline comparable with that previously reported after general anesthesia (GA).

METHODS

Longitudinal cognitive function was analyzed in a cohort of 1819 older adults. Models assessed the rate of change in global and domain-specific cognition over time in participants exposed to RA or GA.

RESULTS

When compared with those unexposed to anesthesia, the postoperative rate of change of the cognitive global z-score was greater in those exposed to both RA (difference in annual decline of -0.041, P = .011) and GA (-0.061, P < .001); these rates did not differ. In analysis of the domain-specific scores, an accelerated decline in memory was observed after GA (-0.065, P < .001) but not RA (-0.011, P = .565).

CONCLUSIONS

Older adults undergoing surgery with RA experience decline of global cognition similar to those receiving GA; however, memory was not affected.

Anaesthetic care of patients undergoing primary hip and knee arthroplasty: consensus recommendations from the International Consensus on Anaesthesia-Related Outcomes after Surgery group (ICAROS) based on a systematic review and meta-analysis

BACKGROUND

Evidence-based international expert consensus regarding anaesthetic practice in hip/knee arthroplasty surgery is needed for improved healthcare outcomes.

METHODS

The International Consensus on Anaesthesia-Related Outcomes after Surgery group (ICAROS) systematic review, including randomised controlled and observational studies comparing neuraxial to general anaesthesia regarding major complications, including mortality, cardiac, pulmonary, gastrointestinal, renal, genitourinary, thromboembolic, neurological, infectious, and bleeding complications. Medline, PubMed, Embase, and Cochrane Library including Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, NHS Economic Evaluation Database, from 1946 to May 17, 2018 were queried. Meta-analysis and Grading of Recommendations Assessment, Development and Evaluation approach was utilised to assess evidence quality and to develop recommendations.

RESULTS

The analysis of 94 studies revealed that neuraxial anaesthesia was associated with lower odds or no difference in virtually all reported complications, except for urinary retention. Excerpt of complications for neuraxial vs general anaesthesia in hip/knee arthroplasty, respectively: mortality odds ratio (OR): 0.67, 95% confidence interval (CI): 0.57-0.80/OR: 0.83, 95% CI: 0.60-1.15; pulmonary OR: 0.65, 95% CI: 0.52-0.80/OR: 0.69, 95% CI: 0.58-0.81; acute renal failure OR: 0.69, 95% CI: 0.59-0.81/OR: 0.73, 95% CI: 0.65-0.82; deep venous thrombosis OR: 0.52, 95% CI: 0.42-0.65/OR: 0.77, 95% CI: 0.64-0.93; infections OR: 0.73, 95% CI: 0.67-0.79/OR: 0.80, 95% CI: 0.76-0.85; and blood transfusion OR: 0.85, 95% CI: 0.82-0.89/OR: 0.84, 95% CI: 0.82-0.87.

CONCLUSIONS

Recommendation: primary neuraxial anaesthesia is preferred for knee arthroplasty, given several positive postoperative outcome benefits; evidence level: low, weak recommendation.

RECOMMENDATION

neuraxial anaesthesia is recommended for hip arthroplasty given associated outcome benefits; evidence level: moderate-low, strong recommendation. Based on current evidence, the consensus group recommends neuraxial over general anaesthesia for hip/knee arthroplasty.

TRIAL REGISTRY NUMBER

PROSPERO CRD42018099935.

Effect of local anesthesia (with lidocaine vs bupivacaine) on cognitive function in patients undergoing elective cataract surgery

Purpose

Postoperative cognitive dysfunction has gained much attention over the last years. Multiple clinical trials have attempted to differentiate the effect of local vs general anesthesia on postoperative cognitive function. The aim of this work was to study the effect of local anesthesia with lidocaine vs bupivacaine on cognitive function.

Patients and methods

This was a prospective randomized trial carried out on 61 patients undergoing elective cataract surgery by phacoemulsification under local anesthesia. Twenty-eight patients received lidocaine 2% and 33 patients received bupivacaine 0.5%. Cognitive assessment for all patients was done preoperatively and 1 week postoperatively using paired associate learning test (PALT) and category verbal fluency (VF) test (animal category).

Results

Regarding cognitive assessment of patients in lidocaine group, there was a statistically significant difference between the mean value of preoperative PALT and postoperative PALT (P-value =0.004), and between the mean value of preoperative VF and postoperative VF (P-value =0.002). As for bupivacaine group, there was a statistically significant difference between the mean value of preoperative PALT and postoperative PALT (P-value =0.021), and between the mean value of preoperative VF and postoperative VF (P-value =0.037). On comparing lidocaine and bupivacaine groups in pre and postoperative PALT & VF scores, there was no statistically significant difference between both groups.

Conclusion

Both lidocaine and bupivacaine caused postoperative cognitive impairment. Lidocaine was found to have a worse effect on cognitive function than bupivacaine, but the difference was not statistically significant.

Neurologic Complications in Noncardiac Surgery

In this article, the incidence of nervous system injuries associated with noncardiac surgery is reviewed briefly. In general, these can be divided into injuries that are clinically apparent (eg, stroke or peripheral nerve damage), which may generally be detectable on clinical examination, and more subtle forms of brain injury (eg, personality changes and postoperative cognitive dysfunction), injuries that are primarily detected by neuropsychological testing.

Anaesthetic interventions for prevention of awareness during surgery

BACKGROUND

General anaesthesia is usually associated with unconsciousness. 'Awareness' is when patients have postoperative recall of events or experiences during surgery. 'Wakefulness' is when patients become conscious during surgery, but have no postoperative recollection of the period of consciousness.

OBJECTIVES

To evaluate the efficacy of two types of anaesthetic interventions in reducing clinically significant awareness:- anaesthetic drug regimens; and- intraoperative anaesthetic depth monitors.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, ISSUE 4 2016); PubMed from 1950 to April 2016; MEDLINE from 1950 to April 2016; and Embase from 1980 to April 2016. We contacted experts to identify additional studies. We performed a handsearch of the citations in the review. We did not search trial registries.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) of either anaesthetic regimens or anaesthetic depth monitors. We excluded volunteer studies, studies of patients prior to skin incision, intensive care unit studies, and studies that only randomized different word presentations for memory tests (not anaesthetic interventions).Anaesthetic drug regimens included studies of induction or maintenance, or both. Anaesthetic depth monitors included the Bispectral Index monitor, M-Entropy, Narcotrend monitor, cerebral function monitor, cerebral state monitor, patient state index, and lower oesophageal contractility monitor. The use of anaesthetic depth monitors allows the titration of anaesthetic drugs to maintain unconsciousness.

DATA COLLECTION AND ANALYSIS

At least two authors independently scanned abstracts, extracted data from the studies, and evaluated studies for risk of bias. We made attempts to contact all authors for additional clarification. We performed meta-analysis statistics in packages of the R language.

MAIN RESULTS

We included 160 studies with 54,109 enrolled participants; 53,713 participants started the studies and 50,034 completed the studies or data analysis (or both). We could not use 115 RCTs in meta-analytic comparisons because they had zero awareness events. We did not merge 27 of the remaining 45 studies because they had excessive clinical and methodological heterogeneity. We pooled the remaining 18 eligible RCTs in meta-analysis. There are 10 studies awaiting classification which we will process when we update the review.The meta-analyses included 18 trials with 36,034 participants. In the analysis of anaesthetic depth monitoring (either Bispectral Index or M-entropy) versus standard clinical and electronic monitoring, there were nine trials with 34,744 participants. The overall event rate was 0.5%. The effect favoured neither anaesthetic depth monitoring nor standard clinical and electronic monitoring, with little precision in the odds ratio (OR) estimate (OR 0.98, 95% confidence interval (CI) 0.59 to 1.62).In a five-study subset of Bispectral Index monitoring versus standard clinical and electronic monitoring, with 34,181 participants, 503 participants gave awareness reports to a blinded, expert panel who adjudicated or judged the outcome for each patient after reviewing the questionnaires: no awareness, possible awareness, or definite awareness. Experts judged 351 patient awareness reports to have no awareness, 87 to have possible awareness, and 65 to have definite awareness. The effect size favoured neither Bispectral Index monitoring nor standard clinical and electronic monitoring, with little precision in the OR estimate for the combination of definite and possible awareness (OR 0.96, 95% CI 0.35 to 2.65). The effect size favoured Bispectral Index monitoring for definite awareness, but with little precision in the OR estimate (OR 0.60, 95% CI 0.13 to 2.75).We performed three smaller meta-analyses of anaesthetic drugs. There were nine studies with 1290 participants. Wakefulness was reduced by ketamine and etomidate compared to thiopental. Wakefulness was more frequent than awareness. Benzodiazepines reduces awareness compared to thiopental, ketamine, and placebo., Also, higher doses of inhaled anaesthetics versus lower doses reduced the risk of awareness.We graded the quality of the evidence as low or very low in the 'Summary of findings' tables for the five comparisons.Most of the secondary outcomes in this review were not reported in the included RCTs.

AUTHORS' CONCLUSIONS

Anaesthetic depth monitors may have similar effects to standard clinical and electrical monitoring on the risk of awareness during surgery. In older studies comparing anaesthetics in a smaller portion of the patient sample, wakefulness occurred more frequently than awareness. Use of etomidate and ketamine lowered the risk of wakefulness compared to thiopental. Benzodiazepines compared to thiopental and ketamine, or higher doses of inhaled anaesthetics versus lower doses, reduced the risk of awareness.

Post-operative cognitive dysfunction at 3 months in adults after non-cardiac surgery: a qualitative systematic review

BACKGROUND

Post-operative cognitive dysfunction is defined as a decline in cognitive functions that occurs after surgery, but different diagnostic criteria and incidences have been reported in medical literature. Our aim was to determine incidence of post-operative cognitive dysfunction 3 months after non-cardiac surgery in adults.

METHODS

A systematic review of available evidence was performed by PRISMA guidelines. A search was done in May-July 2015 on PubMed, EMBASE, CINAHL, LILACS, Scielo, Clinical Trials, and Grey Literature Reports. Inclusion criteria were prospective design studies with patients over 18 years old, surgery under general or regional anesthesia, follow-up for 3 months, and use of a neurocognitive battery for diagnosis. We excluded studies made on cardiac or brain surgery patients. Risk of bias was assessed using tools from National Heart Lung and Blood Institute.

RESULTS

We selected 24 studies. Average age was 68 years. Only five studies reported incidence of cognitive decline for a non-surgical control group. Median number of tests used was 5 (range 3-13). Pooled incidence of post-operative cognitive dysfunction at 3 months was 11.7% [95% CI 10.9-12.5] but with several methodological differences between studies. Increasing age was the most consistent risk factor identified (seven studies).

CONCLUSIONS

Post-operative cognitive dysfunction in patients is frequent, especially in patients over 60 years old. Limitations include methodological differences in studies. Efforts must be made to reach a consensus in definition and diagnosis for future research.

Postoperative cognitive function following general versus regional anesthesia: a systematic review

The effect of anesthetic technique on postoperative outcomes remains in question. This systematic review compares the role of regional versus general anesthesia, with a particular focus on postoperative cognitive function. Potentially relevant articles were identified by searching publicly available computerized databases for this systematic review. Any surgical procedure was accepted with the exception of cardiac, carotid, and neurosurgical procedures. Any regional anesthetic technique was accepted unless combined with a general anesthetic or in conjunction with propofol as a sedative. Any measure of postoperative cognitive function was accepted as long as it was performed no sooner than 7 days postoperatively. Sixteen studies met inclusion criteria and were included in the final analysis. Three studies showed some difference in cognitive function between regional and general anesthesia, whereas the remaining 13 showed no difference between regional and general anesthesia on postoperative cognitive function.

Perioperative outcomes and type of anesthesia in hip surgical patients: An evidence based review

Over the last decades the demand for hip surgery, be it elective or in a traumatic setting, has greatly increased and is projected to expand even further. Concurrent with demographic changes the affected population is burdened by an increase in average comorbidity and serious complications. It has been suggested that the choice of anesthesia not only affects the surgery setting but also the perioperative outcome as a whole. Therefore different approaches and anesthetic techniques have been developed to offer individual anesthetic and analgesic care to hip surgery patients. Recent studies on comparative effectiveness utilizing population based data have given us a novel insight on anesthetic practice and outcome, showing favorable results in the usage of regional vs general anesthesia. In this review we aim to give an overview of anesthetic techniques in use for hip surgery and their impact on perioperative outcome. While there still remains a scarcity of data investigating perioperative outcomes and anesthesia, most studies concur on a positive outcome in overall mortality, thromboembolic events, blood loss and transfusion requirements when comparing regional to general anesthesia. Much of the currently available evidence suggests that a comprehensive medical approach with emphasis on regional anesthesia can prove beneficial to patients and the health care system.

The influence of anesthesia and pain management on cognitive dysfunction after joint arthroplasty: a systematic review

BACKGROUND

Despite the overall success of total joint arthroplasty, patients undergoing this procedure remain susceptible to cognitive decline and/or delirium, collectively termed postoperative cognitive dysfunction. However, no consensus exists as to whether general or regional anesthesia results in a lower likelihood that a patient may experience this complication, and controversy surrounds the role of pain management strategies to minimize the incidence of postoperative cognitive dysfunction.

QUESTIONS/PURPOSES

We systematically reviewed the English-language literature to assess the influence of the following anesthetic and/or pain management strategies on the risk for postoperative cognitive dysfunction in patients undergoing elective joint arthroplasty: (1) general versus regional anesthesia, (2) different parenteral, neuraxial, or inhaled agents within a given type of anesthetic (general or regional), (3) multimodal anesthetic techniques, and (4) different postoperative pain management regimens.

METHODS

A systematic search was performed of the MEDLINE(®) and EMBASE™ databases to identify all studies that assessed the influence of anesthetic and/or pain management strategies on the risk for postoperative cognitive dysfunction after elective joint arthroplasty. Twenty-eight studies were included in the final review, of which 21 (75%) were randomized controlled (Level I) trials, two (7%) were prospective comparative (Level II) studies, two (7%) used a case-control (Level III) design, and three (11%) used retrospective comparative (Level III) methodology.

RESULTS

The evidence published to date suggests that general anesthesia may be associated with increased risk of early postoperative cognitive dysfunction in the early postoperative period as compared to regional anesthesia, although this effect was not seen beyond 7 days. Optimization of depth of general anesthesia with comprehensive intraoperative cerebral monitoring may be beneficial, although evidence is equivocal. Multimodal anesthesia protocols have not been definitively demonstrated to reduce the incidence of postoperative cognitive dysfunction. Nonopioid postoperative pain management techniques, limiting narcotics to oral formulations and avoiding morphine, appear to reduce the risk of postoperative cognitive dysfunction.

CONCLUSIONS

Both anesthetic and pain management strategies appear to influence the risk of early cognitive dysfunction after elective joint arthroplasty, although only one study identified differences that persisted beyond 1 week after surgery. Investigators should strive to use accepted, validated tools for the assessment of postoperative cognitive dysfunction and to carefully report details of the anesthetic and analgesic techniques used in future studies.

Postoperative cognitive dysfunction after total joint arthroplasty in the elderly: a meta-analysis

This meta-analysis consolidated the research on postoperative cognitive dysfunction (POCD) following total joint arthroplasty (TJA). Data from 17 studies that assessed cognition pre- and post-surgery in TJA patients alone (15 studies) or matched TJA and control groups (2 studies) were analysed. Results were grouped by cognitive domain (memory, attention, language, speed, general cognition) and follow-up interval (pre-discharge, 3-6 months post-surgery). The TJA data revealed small declines in reaction time and general cognition pre-discharge, but no evidence of decline 3-6 months post-surgery. Very limited TJA and Control data indicated no group differences in the changes to performance over time; however, the TJA group was cognitively compromised pre- and post-surgery compared to Controls. Further appropriately controlled research is required to clarify whether POCD commonly occurs after TJA.

Neuraxial anesthesia for orthopedic surgery: systematic review and meta-analysis of randomized clinical trials

CONTEXT AND OBJECTIVE

Taking the outcome of mortality into consideration, there is controversy about the beneficial effects of neuraxial anesthesia for orthopedic surgery. The aim of this study was to compare the effectiveness and safety of neuraxial anesthesia versus general anesthesia for orthopedic surgery.

DESIGN AND SETTING

Systematic review at Universidade Federal de Alagoas.

METHODS

We searched the Cochrane Central Register of Controlled Trials (Issue 10, 2012), PubMed (1966 to November 2012), Lilacs (1982 to November 2012), SciELO, EMBASE (1974 to November 2012) and reference lists of the studies included. Only randomized controlled trials were included.

RESULTS

Out of 5,032 titles and abstracts, 17 studies were included. There were no statistically significant differences in mortality (risk difference, RD: -0.01; 95% confidence interval, CI: -0.04 to 0.01; n = 1903), stroke (RD: 0.02; 95% CI: -0.04 to 0.08; n = 259), myocardial infarction (RD: -0.01; 95% CI: -0.04 to 0.02; n = 291), length of hospitalization (mean difference, -0.05; 95% CI: -0.69 to 0.58; n = 870), postoperative cognitive dysfunction (RD: 0.00; 95% CI: -0.04 to 0.05; n = 479) or pneumonia (odds ratio, 0.61; 95% CI: 0.25 to 1.49; n = 167).

CONCLUSION

So far, the evidence available from the studies included is insufficient to prove that neuraxial anesthesia is more effective and safer than general anesthesia for orthopedic surgery. However, this systematic review does not rule out clinically important differences with regard to mortality, stroke, myocardial infarction, length of hospitalization, postoperative cognitive dysfunction or pneumonia.

Thinking through postoperative cognitive dysfunction: How to bridge the gap between clinical and pre-clinical perspectives

Following surgery, patients may experience cognitive decline, which can seriously reduce quality of life. This postoperative cognitive dysfunction (POCD) is mainly seen in the elderly and is thought to be mediated by surgery-induced inflammatory reactions. Clinical studies tend to define POCD as a persisting, generalised decline in cognition, without specifying which cognitive functions are impaired. Pre-clinical research mainly describes early hippocampal dysfunction as a consequence of surgery-induced neuroinflammation. These different approaches to study POCD impede translation between clinical and pre-clinical research outcomes and may hamper the development of appropriate interventions. This article analyses which cognitive domains deteriorate after surgery and which brain areas might be involved. The most important outcomes are: (1) POCD encompasses a wide range of cognitive impairments; (2) POCD affects larger areas of the brain; and (3) individual variation in the vulnerability of neuronal networks to neuroinflammatory mechanisms may determine if and how POCD manifests itself. We argue that, for pre-clinical and clinical research of POCD to advance, the effects of surgery on various cognitive functions and brain areas should be studied. Moreover, in addition to general characteristics, research should take inter-relationships between cognitive complaints and physical and mental characteristics into account.

Postoperative complications: delirium

Delirium is a common feature of the postoperative period, leading to increased morbidity and mortality and significant costs. Multiple factors predispose a patient to delirium in its hypoactive, hyperactive, or mixed forms. Tools have been validated for its quick and accurate identification to ensure timely and effective multidisciplinary intervention and treatment. A significant percentage of patients may require placement in skilled nursing facilities or similar care environments because of the long-lasting effects. The physician must be vigilant in the search for and identification of all forms of delirium and must effectively treat the underlying medical condition and symptoms.

General anaesthesia does not contribute to long-term post-operative cognitive dysfunction in adults: A meta-analysis

CONTEXT

The contribution of anaesthesia itself to post-operative cognitive dysfunction (POCD) or the potential protective effect of one specific type of anaesthesia on the occurrence of POCD is unclear.

AIMS

This is a meta-analysis evaluating the effects of the anaesthetic technique (regional vs. general anaesthesia) on POCD of patients undergoing non-cardiac surgery.

SETTINGS AND DESIGN

Meta-analysis performed in a University affiliated hospital.

METHODS

A search for randomized controlled trials (RCT) comparing regional anaesthesia to general anaesthesia for surgery was done in PUBMED, MEDLINE, EMBASE, EBM Reviews-Cochrane Central Register of Controlled Trials, PsychINFO and Current Contents/all editions in 2009.

STATISTICAL ANALYSIS

Data were analyzed with comprehensive Meta-analysis Version 2.2.044.

RESULTS

Twenty-six RCTs including 2365 patients: 1169 for regional anaesthesia and 1196 for general anaesthesia were retained. The standardized difference in means for the tests included in the 26 RCTs was -0.08 (95% confidence interval: -0.17-0.01; P value 0.094; I-squared = 0.00%). The assessor was blinded to the anaesthetic technique for 12 of the RCTs including only 798 patients: 393 for regional anaesthesia and 405 for general anaesthesia. The standardized difference in means for these 12 studies is 0.05 (-0.10-0.20; P=0.51; I-squared = 0.00%).

CONCLUSIONS

The present meta-analysis does not support the concerns that a single exposure to general anaesthesia in an adult would significantly contribute to permanent POCD after non-cardiac surgery.

Impact of general versus epidural anesthesia on early post-operative cognitive dysfunction following hip and knee surgery

BACKGROUND

Post-operative cognitive dysfunction is the subtle cerebral complication temporally seen following surgery. The aim of this study was to compare the influence of either general anesthesia (GA) or epidural anesthesia (EA) on the early post-operative neurocognitive outcome in elderly (>59 years) subjects undergoing hip and knee surgery.

METHODS

A total of 60 patients were recruited in a prospective, randomized, parallel-group study, comparable by age and sex. They were enrolled and randomized to receive either EA (n = 30) or GA (n = 30). All of them were screened using the Mini Mental State Examination (MMSE), with components of the Kolkata Cognitive Screening Battery. The operated patients were re-evaluated 1 week after surgery using the same scale. The data collected were analyzed to assess statistical significance.

RESULTS

We observed no statistical difference in cognitive behavior in either group pre-operatively, which were comparable with respect to age, sex and type of surgery. Grossly, a significant difference was seen between the two groups with respect to the perioperative changes in verbal fluency for categories and MMSE scores. However, these differences were not significant after the application of the Bonferroni correction for multiple analyses, except the significant differences observed only in the MMSE scores.

CONCLUSIONS

We observed a difference in cognitive outcome with GA compared with EA. Certain aspects of the cognition were affected to a greater extent in this group of patients undergoing hip and knee surgery.

Neuroaxial versus general anaesthesia in geriatric patients for hip fracture surgery: does it matter?

The influence of the mode of anaesthesia on outcome of geriatric patients with hip fractures is a controversial issue in the medical literature. In the light of an ageing society, a conclusive answer to this question is of growing importance. The purpose of this review was to assess the effect of neuroaxial and general anaesthesia on mortality and morbidity in geriatric patients sustaining a hip fracture. Following a current literature search within the Pubmed and Cochrane database (1967-2010), 34 randomised controlled trials, 14 observational studies and eight reviews/meta-analysis publications were included. Potentially outcome-influencing factors such as mortality, deep vein thrombosis, pulmonary embolism, postoperative confusion and other anaesthesia-related outcomes were evaluated. After analysing the current literature with 56 references, covering 18,715 patients with hip fracture, it can be concluded that spinal anaesthesia is associated with significantly reduced early mortality, fewer incidents of deep vein thrombosis, less acute postoperative confusion, a tendency to fewer myocardial infarctions, fewer cases of pneumonia, fatal pulmonary embolism and postoperative hypoxia. General anaesthesia has the advantages of having a lower incidence of hypotension and a tendency towards fewer cerebrovascular accidents compared to neuroaxial anaesthesia. Otherwise, general anaesthesia and respiratory diseases were significant predictors of morbidity in hip fracture patients. These data suggest that regional anaesthesia is the preferred technique, but the limited evidence available does not permit a definitive conclusion to be drawn for mortality or other outcomes. For hip fracture surgery, the choice of anaesthesia (general or neuroaxial) is made by the anaesthesiologist and is based on the patient's preference, comorbidities, potential general postoperative complications and the clinical experience of the anaesthesiologist. The overall therapeutic approach in hip fracture care should be determined jointly by the orthopaedic surgeon, the geriatrician and the anaesthesiologist (multidisciplinary approach).

Cerebral microembolization during primary total hip arthroplasty and neuropsychologic outcome: a pilot study

BACKGROUND

Intraoperative cerebral microembolization occurs in a substantial proportion of patients undergoing THA. Historically, postoperative cognitive dysfunction has been attributed to different factors, including anesthesia, but the influence of the surgery has not been thoroughly examined.

QUESTIONS/PURPOSES

We conducted a prospective, controlled clinical trial to assess intraoperative cerebral microembolization during THA and neuropsychologic outcome.

METHODS

The presence of a patent foramen ovale (PFO) also was investigated, using transcranial Doppler, to determine whether this affected cerebral microembolic incidence and load and whether microemboli occurred as a result of specific surgical activity. Forty-five patients were recruited who underwent THA and neuropsychologic assessment; a battery of tests was administered preoperatively and at 6 weeks and 6 months postoperatively.

RESULTS

Overall, patients showed improvement in total neuropsychologic change scores at both postoperative intervals. The incidence of cerebral microembolization for THA was 23%. The prevalence of PFO was 37%. PFO did not appear to influence microemboli load or incidence. More microemboli were seen during femoral component insertion and impaction.

CONCLUSIONS

Intraoperative cerebral microembolization occurs in a substantial proportion of patients during THA recorded by transcranial Doppler. The microemboli load is low and is not influenced by the presence of PFO. Certain surgical activities seem responsible for greater cerebral microemboli generation. However, neuropsychologic outcome was not affected postoperatively by microemboli or other operative or patient variables.

Does regional anesthesia improve outcome after total knee arthroplasty?

Total knee arthroplasty (TKA) is amenable to various regional anesthesia techniques that may improve patient outcome. We sought to answer whether regional anesthesia decreased mortality, cardiovascular morbidity, deep venous thrombosis and pulmonary embolism, blood loss, duration of surgery, pain, opioid-related adverse effects, cognitive defects, and length of stay. We also questioned whether regional anesthesia improved rehabilitation. To do so, we performed a systematic review of the contemporary literature comparing general anesthesia and/or systemic analgesia with regional anesthesia and/or regional analgesia for TKA. To reflect contemporary surgical and anesthetic practice, only randomized, controlled trials from 1990 onward were included. We identified 28 studies involving 1538 patients. There was insufficient evidence from randomized, controlled trials alone to conclude if anesthetic technique influenced mortality, cardiovascular morbidity other than postoperative hypotension, or the incidence of deep venous thrombosis and pulmonary embolism when using thromboprophylaxis. Our review suggests there was no difference in perioperative blood loss or duration of surgery in patients who received general anesthesia versus regional anesthesia. Compared with general anesthesia and/or systemic analgesia, regional anesthesia and/or analgesia reduced postoperative pain, morphine consumption, and opioid-related adverse effects. Length of stay may be reduced and rehabilitation facilitated for patients undergoing regional anesthesia and analgesia for TKA.

A comparison of regional and general anaesthesia for total replacement of the hip or knee: a meta-analysis

We performed a meta-analysis to evaluate the relative efficacy of regional and general anaesthesia in patients undergoing total hip or knee replacement. A comprehensive search for relevant studies was performed in PubMed (1966 to April 2008), EMBASE (1969 to April 2008) and the Cochrane Library. Only randomised studies comparing regional and general anaesthesia for total hip or knee replacement were included. We identified 21 independent, randomised clinical trials. A random-effects model was used to calculate all effect sizes. Pooled results from these trials showed that regional anaesthesia reduces the operating time (odds ratio (OR) -0.19; 95% confidence interval (CI) -0.33 to -0.05), the need for transfusion (OR 0.45; 95% CI 0.22 to 0.94) and the incidence of thromboembolic disease (deep-vein thrombosis OR 0.45, 95% CI 0.24 to 0.84; pulmonary embolism OR 0.46, 95% CI 0.29 to 0.80). Regional anaesthesia therefore seems to improve the outcome of patients undergoing total hip or knee replacement.

Does regional anaesthesia improve outcome after total hip arthroplasty? A systematic review

Total hip arthroplasty (THA) is amenable to a variety of regional anaesthesia (RA) techniques that may improve patient outcome. We sought to answer whether RA decreased mortality, cardiovascular morbidity, deep venous thrombosis (DVT) and pulmonary embolism (PE), blood loss, duration of surgery, pain, opioid-related adverse effects, cognitive defects, and length of stay. We also questioned whether RA improved rehabilitation. To do so, we performed a systematic review of the contemporary literature to compare general anaesthesia (GA) and RA and also systemic and regional analgesia for THA. To reflect contemporary surgical and anaesthetic practice, only randomized controlled trials (RCTs) from 1990 onward were included. We identified 18 studies involving 1239 patients. Only two of the 18 trials were of Level I quality. There is insufficient evidence from RCTs alone to conclude if anaesthetic technique influenced mortality, cardiovascular morbidity, or the incidence of DVT and PE when using thromboprophylaxis. Blood loss may be reduced in patients receiving RA rather than GA for THA. Our review suggests that there is no difference in duration of surgery in patients who receive GA or RA. Compared with systemic analgesia, regional analgesia can reduce postoperative pain, morphine consumption, and nausea and vomiting. Length of stay is not reduced and rehabilitation does not appear to be facilitated by RA or analgesia for THA.

The effects of surgery and anesthesia on memory and cognition

This chapter describes current findings from the research into postoperative cognitive dysfunction (POCD) following cardiac and non-cardiac surgery in older adults. The evidence suggests that a significant proportion of patients show POCD in the early weeks following surgery and anesthesia. Specific domains of cognition are affected, especially memory. Much less evidence supports the presence of POCD several months or years after surgery, suggesting that POCD may be transient. However, several methodological issues make it difficult to compare findings across studies. Increasing age is among the most consistently reported patient-related risk factor. Other factors more directly related to the surgery and anesthesia are likely to contribute to the pathogenesis of POCD, including inflammatory processes triggered by the surgical procedure. Animal studies have provided valuable findings otherwise not possible in human studies; these include a correlation between the inflammatory response in the hippocampus and the development of POCD in rodents.

Evidence-based clinical update: general anesthesia and the risk of delirium and postoperative cognitive dysfunction

PURPOSE

The purpose of this structured, evidence-based, clinical update was to identify the best evidence comparing general and regional anesthesia and their influence on delirium or cognitive dysfunction (POCD) in the postoperative period.

SOURCE

In June 2005 a structured search of MEDLINE from 1966 to present using OVID software was undertaken. Medical subject headings and textwords describing both delirium and POCD were employed. OVID's Therapy (sensitivity) algorithm was used to maximize the detection of randomized trials. The bibliographies of eligible publications were hand-searched to identify trials not identified in the electronic search. Publications enrolling children were excluded. Levels of evidence and grades of recommendations were scored using Centre for Evidence Based Medicine criteria.

PRINCIPAL FINDINGS

A total of 18 unique randomized controlled trials were identified: two evaluating delirium; ten evaluating POCD; and six evaluating both. Outcomes for delirium were abstracted from eight trials that enrolled 765 patients (387 regional anesthesia; 378 general anesthesia). Outcomes for POCD were identified from 16 trials that enrolled 2,708 patients (1,313 regional anesthesia; 1,395 general anesthesia). Both delirium (11-43%) and POCD (15-25%) were relatively common in trials actively seeking these outcomes. Consistent Level 2b evidence suggests no significant increase in delirium in patients receiving general anesthesia compared with those receiving regional anesthesia. Similarly, consistent Level 1 evidence indicates that exposure to general anesthesia is not significantly associated with POCD.

CONCLUSION

Available randomized controlled trials suggest that there is no significant difference in the incidence of delirium or POCD when general anesthesia and regional anesthesia are compared.

Postoperative cognitive dysfunction: incidence and prevention

Postoperative cognitive dysfunction (POCD) is a decline in cognitive function for weeks or months after surgery. Due to its subtle nature, neuropsychological testing is necessary for its detection. The interpretation of literature on POCD is difficult because of numerous methodological limitations, particularly the different definitions of POCD and the lack of data from control groups. POCD is common after cardiac surgery, and recent studies have now verified that POCD also exists after major non-cardiac surgery, although at a lower incidence. The risk of POCD increases with age, and the type of surgery is also important because there is a very low incidence associated with minor surgery. Regional anaesthesia does not seem to reduce the incidence of POCD, and cognitive function does not seem to improve after carotid surgery as has previously been suggested.

The effect of spinal anesthesia on blood transfusion rate in total joint arthroplasty

BACKGROUND

Total joint arthroplasty (TJA) patients often receive allogeneic blood transfusion. The use of regional anesthesia (RA) is thought to protect against the need for blood transfusion, but many randomized trials of RA in TJA have not reached this conclusion unanimously. We sought to describe the effect of RA on allogeneic transfusion in a large retrospective TJA series.

METHODS

We examined data from all TJAs performed in Edmonton, Alberta, in the year 2000 (n = 1875) and used logistic regression modelling to determine the relation between the use of RA and allogeneic transfusion.

RESULTS

Twenty-eight percent of TJA subjects received an allogeneic transfusion. Transfusion was independently associated with increasing age, decreasing body mass, decreasing preoperative hemoglobin, female sex, increased comorbidity and prolonged operative time. After controlling for these factors, we found that the use of RA (in the form of spinal anesthesia) compared with general anesthesia reduced the odds ratio (OR) for transfusion to 0.729 (95% confidence interval [CI] 0.559-0.949). This represents the combination of a strong relation between RA and transfusion prevention in hip arthroplasty (OR 0.646, 95% CI 0.443-0.944) and a nonsignificant relation in knee arthroplasty (OR 0.825, 95% CI 0.564-1.208).

CONCLUSION

The use of spinal anesthesia protects against allogeneic transfusion in arthroplasty of the hip but not the knee. This is consistent with what is known about the hemodynamic consequences of spinal anesthesia.

Review of randomised trials using the post-randomised consent (Zelen's) design

BACKGROUND

In 1979, Zelen described a trial method of randomising participants before acquiring consent in order to enhance recruitment to clinical trials. The method has been criticised ethically due to lack of consent and scientifically due to high crossover rates. This paper reviews recent published trials using this method and describes the reasons authors gave for using the method, examines the crossover rates, and looks at the quality of identified trials.

METHODS

Literature review searching for all citations to the relevant Zelen's papers of trials published since 1990 plus inclusion of trials from personal knowledge.

RESULTS

We identified 58 relevant trials. The most common justification for the use of Zelen method was to avoid the introduction of bias (e.g., to avoid the Hawthorne effect). Few trialists had explicitly used the design to enhance participant recruitment. Most trials (n=41) experienced some crossover from one group to the other (median crossover=8.9%, mean=13.8%, IQR 2.6% to 15%) although this was usually within acceptable limits.

CONCLUSION

The most important reason stated by authors for using Zelen's method was to limit bias. Zelen's method, if carefully used, can avoid 'resentful demoralisation' and the Hawthorne effect biasing a trial. Unlike a previous review, we found that crossover was not a problem for most trials.

Local or general anesthesia for open hernia repair: a randomized trial

OBJECTIVE

To compare patient outcome following repair of a primary groin hernia under local (LA) or general anesthesia (GA) in a randomized clinical trial.

SUMMARY BACKGROUND DATA

LA hernia repair is thought to be safer for patients, causes less postoperative pain, cost less, and is associated with a more rapid recovery when compared with the same operation performed under GA.

METHODS

All patients presenting to three surgeons during the study period with a primary groin hernia were considered eligible. Outcome parameters measured including tests of vigilance, divided attention, sustained attention, memory, cognitive function, pain, return to normal activity, and costs.

RESULTS

Two hundred seventy-nine patients were randomized to LA or GA hernia repair; 276 of these had an operation, with 138 participants in each group. At 6, 24, and 72 hours postoperatively there were no differences in vigilance or divided attention between the groups. Similarly, memory, sustained attention, and cognitive function were not impaired in either group. Although physical activity was significantly impaired at 24 hours, this and return to usual social activities were similar in both groups. While patients in the LA group had significantly less pain on moving, at 6 hours they were less likely to recommend the same operation to someone else. GA hernia repair cost 4% more than the same operation under LA.

CONCLUSIONS

There are no major differences in patient recovery after LA or GA hernia repair. Patients should be offered a choice of anesthesia, LA or GA, for repair of their groin hernia.

Does anaesthesia cause postoperative cognitive dysfunction? A randomised study of regional versus general anaesthesia in 438 elderly patients

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a common complication after cardiac and major non-cardiac surgery with general anaesthesia in the elderly. We hypothesized that the incidence of POCD would be less with regional anaesthesia rather than general.

METHODS

We included patients aged over 60 years undergoing major non-cardiac surgery. After giving written informed consent, patients were randomly allocated to general or regional anaesthesia. Cognitive function was assessed using four neuropsychological tests undertaken preoperatively and at 7 days and 3 months postoperatively. POCD was defined as a combined Z score >1.96 or a Z score >1.96 in two or more test parameters.

RESULTS

At 7 days, POCD was found in 37/188 patients (19.7%, [14.3-26.1%]) after general anaesthesia and in 22/176 (12.5%, [8.0-18.3%]) after regional anaesthesia, P = 0.06. After 3 months, POCD was present in 25/175 patients (14.3%, [9.5-20.4%]) after general anaesthesia vs. 23/165 (13.9%, [9.0-20.2%]) after regional anaesthesia, P = 0.93. The incidence of POCD after 1 week was significantly greater after general anaesthesia when we excluded patients who did not receive the allocated anaesthetic: 33/156 (21.2%[15.0-28.4%]) vs. 20/158 (12.7%[7.9-18.9%]) (P = 0.04). Mortality was significantly greater after general anaesthesia (4/217 vs. 0/211 (P < 0.05)).

CONCLUSION

No significant difference was found in the incidence of cognitive dysfunction 3 months after either general or regional anaesthesia in elderly patients. Thus, there seems to be no causative relationship between general anaesthesia and long-term POCD. Regional anaesthesia may decrease mortality and the incidence of POCD early after surgery.

Postoperative cognitive dysfunction versus complaints: a discrepancy in long-term findings

This review describes the discrepancy in findings between postoperative cognitive performance and postoperative cognitive complaints long time after an operation under general anesthesia. Shortly (from 6 hr to 1 week) after an operation a decline in cognitive performance is reported in most studies. However, long time (from 3 weeks to 1-2 years) after an operation this is rarely found although some patients are still reporting cognitive complaints. In general this kind of research is suffering from severe methodological problems (use of insensitive tests, lack of control groups, lack of parallel tests, different definitions of cognitive decline). However, these problems cannot totally explain the discrepancy in findings in the long term. Thus, there are patients who have persistent cognitive complaints long time after an operation, that cannot be measured with cognitive tests. More psychological factors such as fixation on short-term cognitive dysfunction, mood, coping style, and personality are possible explanations for these cognitive complaints in the long term. As a consequence, these factors should be a topic in future research elucidating the persistence of these cognitive complaints long time after an operation under general anesthesia.

Long-term consequences of repeated pentobarbital anaesthesia on choice reaction time performance in ageing rats

Recent studies have suggested that anaesthesia may be a factor in cognitive decline with age. We examined the effect of repeated (eight times) anaesthesia with pentobarbital on reaction time performance in rats in a longitudinal study. Treated rats had faster response times and made more premature responses than the control rats when they were older than 21 months. The results suggest that repeated anaesthesia during the lifespan can lead to an increase in impulsivity, as assessed by a choice reaction time test, during the later stages of life in the rat. These findings support the theory that repeated anaesthesia is a biological factor that affects cognitive ageing.

Reduction of postoperative mortality and morbidity with epidural or spinal anaesthesia: results from overview of randomised trials

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<0.001). There were also reductions in myocardial infarction and renal failure. Although there was limited power to assess subgroup effects, the proportional reductions in mortality did not clearly differ by surgical group, type of blockade (epidural or spinal), or in those trials in which neuraxial blockade was combined with general anaesthesia compared with trials in which neuraxial blockade was used alone.

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.

Cognitive dysfunction 1-2 years after non-cardiac surgery in the elderly. ISPOCD group. International Study of Post-Operative Cognitive Dysfunction

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a well-recognised complication of cardiac surgery, but evidence of POCD after general surgery has been lacking. We recently showed that POCD was present in 9.9% of elderly patients 3 months after major non-cardiac surgery. The aim of the present study was to investigate whether POCD persists for 1-2 years after operation.

METHODS

A total of 336 elderly patients (median age 69 years, range 60-86) was studied after major surgery under general anesthesia. Psychometric testing was performed before surgery and at a median of 7, 98 and 532 days postoperatively using a neuropsychological test battery with 7 subtests. A control group of 47 non-hospitalised volunteers of similar age were tested with the test battery at the same intervals.

RESULTS

1-2 years after surgery, 35 out of 336 patients (10.4%, CI: 7.2-13.7%) had cognitive dysfunction. Three patients had POCD at all three postoperative test sessions (0.9%). From our definition of POCD, there is only a 1:64000 likelihood that a single subject would have POCD at all three test points by chance. Logistic regression analysis identified age, early POCD, and infection within the first three postoperative months as significant risk factors for long-term cognitive dysfunction. Five of 47 normal controls fulfilled the criteria for cognitive dysfunction 1-2 years after initial testing (10.6%, CI: 1.8-19.4%), i.e. a similar incidence of age-related cognitive impairment as among patients.

CONCLUSION

POCD is a reversible condition in the majority of cases but may persist in approximately 1% of patients.

Mechanisms behind and treatment of sudden, unexpected circulatory collapse during central neuraxis blockade

Judging from the number of cases reported in the literature, severe bradycardia and/or asystole in association with central neuraxis blockade fortunately seems a rare complication. However, short periods of extreme bradycardia may go unnoticed and manifest cases, especially when outcome is favourable, may go unreported, and thus the real incidence may be much higher. Although the decrease in systemic blood pressure as a result of central neuraxis blockade is caused by various mechanisms, the most important factor causing severe hypotension, bradycardia and circulatory collapse is decreased venous return, and both prevention and treatment are aimed at preserving or restoring adequate venous return to the heart. Correction of preoperative hypovolaemia, limiting the extent of sensory blockade and positioning the patient so that gravity promotes venous return are the most significant preventive measures. Although a widespread custom, controversy exists regarding the efficacy of a preload; for certain categories of patients intravenous volume loading may be deleterious, and rather than a routine measure, the decision to administer a preload should be based on the clinical situation and the condition of the individual patient. For the treatment of mild bradycardia, anticholinergic drugs are the first choice. Hypotension may be treated by promoting venous return using gravity, by intravenous fluid infusion, by intravenous administration of sympathomimetic drugs, or by a combination of all three measures. In the event of sudden circulatory collapse, the first therapeutic measure that is usually immediately effective is elevation of the legs, thus promoting venous return.

Central nervous system dysfunction after anesthesia in the geriatric patient

Cerebral infarction, bleeding, long-lasting hypofusion, and profound hypoxia are well-known factors behind central nervous system dysfunction after anesthesia. Other explanations may be the metabolic-endocrine stress response and psychologic factors related to changes in the environment. The clinical presentations can be obvious as in cerebral death or stroke but delirium also may be readily recognized. A more subtle and long-lasting deterioration in cognitive function is called postoperative cognitive dysfunction. This condition can only be detected with the use of neuropsychologic testing and recently, postoperative cognitive dysfunction has been detected as the most common cerebral complication after noncardiac surgery in elderly patients.