Anaesthesia
-
Review Comparative Study
Nitrous oxide-based vs. nitrous oxide-free general anaesthesia and accidental awareness in surgical patients: an abridged Cochrane systematic review.
Accidental awareness during general anaesthesia can arise from a failure to deliver sufficient anaesthetic agent, or from a patient's resistance to an expected sufficient dose of such an agent. Awareness is 'explicit' if the patient is subsequently able to recall the event. We conducted a systematic review into the effect of nitrous oxide used as part of a general anaesthetic on the risk of accidental awareness in people over the age of five years undergoing general anaesthesia for surgery. ⋯ There were a total of three accidental awareness events reported in two studies, one of which reported that the awareness was the result of a kink in a propofol intravenous line. There were insufficient data to conduct a meta- or sub-group analysis and there was insufficient evidence to draw outcome-related conclusions. We can, however, recommend that future studies focus on potentially high-risk groups such as obstetric or cardiac surgery patients, or those receiving neuromuscular blocking drugs or total intravenous anaesthesia.
-
Elderly patients with hip fracture experience high morbidity and mortality, and are often undertreated for pain. Acute pain management in the elderly is challenging, with physiological frailty, medical comorbidities and cognitive impairment commonly compounding pain assessment and treatment. Guidelines outlining current best practice for acute pain management in the elderly now exist, but evidence suggests that practice remains variable and there continues to be scope for improvement. ⋯ There is also moderate evidence that nerve blocks may contribute to reduced rates of delirium, and some suggestion of reduced length of inpatient stay, morbidity and mortality, although limited evidence is available. Fascia iliaca blocks are emerging as a block of choice, with evidence they can be safely and rapidly administered under ultrasound guidance in the acute setting, by both trained medical and nursing staff, with good effect. Ideally, comprehensive pain protocols for elderly hip fracture patients are required, that integrate evidence-based fascia iliaca block use, timely and repeated pain assessment, and multidisciplinary orthogeriatric patient care.
-
It is commonly assumed that loss of responsiveness and recovery of responsiveness occur at similar concentrations of propofol. However, the 'conscious' and 'anaesthetised' conditions produced by general anaesthetics may behave as two bistable states. We hypothesised that loss of responsiveness and recovery of responsiveness occur at different propofol concentrations. ⋯ Propofol plasma concentration and the corresponding bispectral index values measured at minute 7 and minute 14 of the long step performed at loss of responsiveness were 2.6 (1.2-4.7) vs. 2.6 (1.3-4.3) at recovery of responsiveness, (p = 0.96) and 61.2 (49.0-77.0) vs. 58.4 (45.0-74.0), (p = 0.058), respectively. Loss of responsiveness and recovery of responsiveness appear to occur at different propofol concentrations. However, it is possible that, if equilibration was not achieved between plasma and effect-sites at the end of each 7-min step, the higher concentrations found at loss of responsiveness compared with those observed during recovery of responsiveness could be explained by a possible bias in estimations of the effect-site concentrations of propofol by the Schnider model, rather than neural inertia.
-
'Obstetric anaesthesia is a litigious area of medical practice - patient expectations are high, and many of the interventions undertaken by anaesthetists are performed urgently or emergently, frequently out of hours. The complications that occur during obstetric practice are not unique to this area of anaesthesia, but some of the physiological and anatomical changes that take place during pregnancy can affect the frequency with which these happen. In this narrative review, we hope to cover a few of the more common complications in obstetric anaesthesia, as well as some of the more severe, yet less frequently occurring problems.
-
Randomized Controlled Trial
A triple-blind, placebo-controlled randomised trial of the ilioinguinal-transversus abdominis plane (I-TAP) nerve block for elective caesarean section.
This study investigated the efficacy of a new ilioinguinal-transversus abdominis plane block when used as a component of multimodal analgesia. We conducted a prospective, triple-blind, placebo-controlled randomised study of 100 women undergoing elective caesarean section. All women had spinal anaesthesia with hyperbaric bupivacaine, 15 μg fentanyl and 150 μg morphine, as well as 100 mg diclofenac and 1.5 g paracetamol rectally. ⋯ Post-hoc analysis showed that the ilioinguinal-transversus abdominis group was less likely to use ≥ 1000 μg fentanyl compared with the control group (2% vs. 16%; p = 0.016). There were no differences in opioid-related side-effects or maternal satisfaction with analgesia. The addition of the ilioinguinal-transversus abdominis plane block provides superior analgesia to our usual multimodal analgesic regimen.