How safe are regional techniques? Evidence from large studies with big data

No Abstract. Keywords: regional techniques, safety, drug toxicity, sharp trauma, blunt trauma, stretch injury, nerve ischaemi

Context-sensitive fluid administration: what, when and how much?

No Abstract. Keywords: context-sensitive fluid administration, fluid therapy, benefits, har

Anaesthesia for lung volume reduction surgery

No Abstract Available. Southern African Journal of Anaesthesia & Analgesia Vol. 11 (3) 2005: 103-10

Drug administration errors by South African anaesthetists - a survey

Objectives. To investigate the incidence, nature of and factors contributing towards wrong drug administrations by South African anaesthetists. Design. A confidential, self-reporting survey was sent out to the 720 anaesthetists on the database of the South African Society of Anaesthesiologists. Results. A total of 133 questionnaires were returned for analysis (18.5% response rate). Of the respondents, 125 (94%) admitted to having inadvertently administered a wrong drug. Thirty respondents (22.6%) said they had made errors on at least four occasions. A total of 303 specific wrong drug administrations were described. Nearly 50% involved muscle relaxants. A further 43 incidents (14%) involved the erroneous administration of vasoactive drugs. Five deaths and 3 nonfatal cardiac arrests were reported. In 9.9% of incidents the anaesthetic time was prolonged by more than 30 minutes. Contributory causes identified included syringe swaps (40%), misidentification of drugs (27.1%), fatigue (14.1%), distractions (4.7%), and mislabelling of syringes (4.7%). Only 19% of respondents regularly use colour-coded syringe labels complying with the national standard. Conclusions. Most anaesthetists experienced at least one drug error. The incidence of wrong drug administrations by South African anaesthetists appears to be similar to that in Australasia and Canada. The commonest error was a ‘syringe swap' involving muscle relaxants. Most drug errors are inconsequential. An important minority of incidents result in severe morbidity or death. The study supports efforts to improve ampoule labelling, to encourage the use of syringe labels based on the international colour code and to develop a national reporting system for such incidents. South African Medical Journal Vol. 96(7) 2006: 630-63

A modern look at hypertension and anaesthesia

Hypertension is common among patients presenting for surgery, and is frequently untreated or inadequately treated. While the approach to the patient with hypertension presenting for anaesthesia is controversial, and the evidence base for appropriate clinical decisions is weak, this is a problem that practising clinical anaesthetists face on a regular basis. This article seeks to present a unified approach to the problem of a hypertensive patient presenting for surgery, and offers suggestions as to the appropriate management options. As far as possible, the recommendations contained in this article have been based on the best available evidence. The authors suggest that moderate degrees of hypertension (up to 180/120 mmHg), without obvious target organ disease, should never be grounds for postponing surgery. Even with greater degrees of hypertension, the relative risk of postponing surgery should always be considered. There is little evidence that, in patients without target organ disease, delaying surgery in order to establish antihypertensive therapy is beneficial. For very severe hypertension, the benefits of delaying surgery to establish adequate hypertensive control must be weighed against the risk of delayed surgery. Where a surgical delay is considered, adequate time to establish appropriate blood pressure control must be allowed, and there is no place for sudden “cosmetic” correction of blood pressure immediately prior to anaesthesia. Previously undiagnosed hypertension, presenting for the first time at surgery, requires a basic investigation of target organ disease prior to anaesthesia, and appropriate subsequent follow-up referral for further management.Keywords: hypertension, anaesthesia, ris

A modern look at hypertension and anaesthesia

Hypertension is common among patients presenting for surgery, and is frequently untreated or inadequately treated. While the approach to the patient with hypertension presenting for anaesthesia is controversial, and the evidence base for appropriate clinical decisions is weak, this is a problem that practising clinical anaesthetists face on a regular basis. This article seeks to present a unified approach to the problem of a  hypertensive patient presenting for surgery, and offers suggestions as to the appropriate management options. As far as possible, the recommendations contained in this article have been based on the best available evidence. The authors suggest that moderate degrees of hypertension (up to 180/120 mmHg), without obvious target organ disease, should never be grounds for postponing surgery. Even with greater degrees of hypertension, the relative risk of postponing surgery should always be considered. There is little evidence that, in patients without target organ disease, delaying surgery in order to establish  antihypertensive therapy is beneficial. For very severe hypertension, the benefits of delaying surgery to establish adequate hypertensive control must be weighed against the risk of delayed surgery. Where a surgical delay is considered, adequate time to establish appropriate blood pressurecontrol must be allowed, and there is no place for sudden “cosmetic” correction of blood pressure immediately prior to anaesthesia. Previously undiagnosed hypertension, presenting for the first time at surgery, requires a basic investigation of target organ disease prior to anaesthesia, and appropriate subsequent follow-up referral for further management

Drug administration errors by South African anaesthetists – a survey

No Abstract. Southern African Journal of Anaesthesia and Analgesia Vol. 12(1) 2006: 4

The anion study: effect of different crystalloid solutions on acid base balance, physiology, and survival in a rodent model of acute isovolaemic haemodilution

Background: Commercially available crystalloid solutions used for volume replacement do not exactly match the balance of electrolytes found in plasma. Large volume administration may lead to electrolyte imbalance and potential harm. We hypothesised that haemodilution using solutions containing different anions would result in diverse biochemical effects, particularly on acid-base status, and different outcomes. Methods: Anaesthetised, fluid-resuscitated, male Wistar rats underwent isovolaemic haemodilution by removal of 10% blood volume every 15 min, followed by replacement with one of three crystalloid solutions based on acetate, lactate, or chloride. Fluids were administered in a protocolised manner to achieve euvolaemia based on echocardiography-derived left ventrical volumetric measures. Removed blood was sampled for plasma ions, acid-base status, haemoglobin, and glucose. This cycle was repeated at 15-min intervals until death. The primary endpoint was change in plasma bicarbonate within each fluid group. Secondary endpoints included time to death and cardiac function. Results: During haemodilution, chloride-treated rats showed significantly greater decreases in plasma bicarbonate and strong ion difference levels compared with acetate- and lactate-treated rats. Time to death, total volume of fluid administered: chloride group 56 (3) ml, lactate group 62 (3) ml, and acetate group 65 (3) ml; haemodynamic and tissue oxygenation changes were, however, similar between groups. Conclusions: With progressive haemodilution, resuscitation with a chloride-based solution induced more acidosis compared with lactate- and acetate-based solutions, but outcomes were similar. No short-term impact was seen from hyperchloraemia in this model

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Background Perioperative fluid strategies influence clinical outcomes following major surgery. Many intravenous fluid preparations are based on simple solutions, such as normal saline, that feature an electrolyte composition that differs from that of physiological plasma. Buffered fluids have a theoretical advantage of containing a substrate that acts to maintain the body’s acid-base status - typically a bicarbonate or a bicarbonate precursor such as maleate, gluconate, lactate, or acetate. Buffered fluids also provide additional electrolytes, including potassium, magnesium, and calcium, more closely matching the electrolyte balance of plasma. The putative benefits of buffered fluids have been compared with those of non-buffered fluids in the context of clinical studies conducted during the perioperative period. This review was published in 2012, and was updated in 2017. Objectives To review effects of perioperative intravenous administration of buffered versus non-buffered fluids for plasma volume expansion or maintenance, or both, on clinical outcomes in adults undergoing all types of surgery. Search methods We electronically searched the Clinicaltrials.gov major trials registry, the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 6) in the Cochrane Library, MEDLINE (1966 to June 2016), Embase (1980 to June 2016), and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to June 2016). We handsearched conference abstracts and, when possible, contacted leaders in the field. We reran the search in May 2017. We added one potential new study of interest to the list of ‘Studies awaiting classification' and will incorporate this trial into formal review findings when we prepare the review update. Selection criteria Only randomized controlled trials that compared buffered versus non-buffered intravenous fluids for surgical patients were eligible for inclusion. We excluded other forms of comparison such as crystalloids versus colloids and colloids versus different colloids. Data collection and analysis Two review authors screened references for eligibility, extracted data, and assessed risks of bias. We resolved disagreements by discussion and consensus, in collaboration with a third review author. We contacted trial authors to request additional information when appropriate. We presented pooled estimates for dichotomous outcomes as odds ratios (ORs) and for continuous outcomes as mean differences (MDs), with 95% confidence intervals (CIs). We analysed data via Review Manager 5.3 using fixed-effect models, and when heterogeneity was high (I² > 40%), we used random-effects models. Main results This review includes, in total, 19 publications of 18 randomized controlled trials with a total of 1096 participants. We incorporated five of those 19 studies (330 participants) after the June 2016 update. Outcome measures in the included studies were thematically similar, covering perioperative electrolyte status, renal function, and acid-base status; however, we found significant clinical and statistical heterogeneity among the included studies. We identified variable protocols for fluid administration and total volumes of fluid administered to patients intraoperatively. Trial authors variably reported outcome data at disparate time points and with heterogeneous patient groups. Consequently, many outcome measures are reported in small group sizes, reducing overall confidence in effect size, despite relatively low inherent bias in the included studies. Several studies reported orphan outcome measures. We did not include in the results of this review one large, ongoing study of saline versus Ringer's solution. We found insufficient evidence on effects of fluid therapies on mortality and postoperative organ dysfunction (defined as renal insufficiency leading to renal replacement therapy); confidence intervals were wide and included both clinically relevant benefit and harm: mortality (Peto OR 1.85, 95% CI 0.37 to 9.33; I² = 0%; 3 trials, 6 deaths, 276 participants; low-quality evidence); renal insufficiency (OR 0.82, 95% CI 0.34 to 1.98; I² = 0%; 4 trials, 22 events, 276 participants; low-quality evidence). We noted several metabolic differences, including a difference in postoperative pH measured at end of surgery of 0.05 units - lower in the non-buffered fluid group (12 studies with a total of 720 participants; 95% CI 0.04 to 0.07; I² = 61%). However, this difference was not maintained on postoperative day one. We rated the quality of evidence for this outcome as moderate. We observed a higher postoperative serum chloride level immediately after operation, with use of non-buffered fluids reported in 10 studies with a total of 530 participants (MD 6.77 mmol/L, 95% CI 3.38 to 10.17), and this difference persisted until day one postoperatively (five studies with a total of 258 participants; MD 8.48 mmol/L, 95% CI 1.08 to 15.88). We rated the quality of evidence for this outcome as moderate. Authors' conclusions Current evidence is insufficient to show effects of perioperative administration of buffered versus non-buffered crystalloid fluids on mortality and organ system function in adult patients following surgery. Benefits of buffered fluid were measurable in biochemical terms, particularly a significant reduction in postoperative hyperchloraemia and metabolic acidosis. Small effect sizes for biochemical outcomes and lack of correlated clinical follow-up data mean that robust conclusions on major morbidity and mortality associated with buffered versus non-buffered perioperative fluid choices are still lacking. Larger studies are needed to assess these relevant clinical outcomes