Anaesthesia
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Randomized Controlled Trial
Gastric ultrasound in the third trimester of pregnancy: a randomised controlled trial to develop a predictive model of volume assessment.
Bedside gastric ultrasonography can be performed reliably by anaesthetists to assess gastric content in the peri-operative period. We aimed to study the relationship between gastric cross-sectional area, assessed by ultrasound, and volumes of clear fluids ingested by pregnant women. We recruited 60 non-labouring third-trimester pregnant women in a randomised controlled and assessor-blinded study. ⋯ A cut-off value of 9.6 cm2 discriminated ingested volumes ≥ 1.5 ml.kg-1 with a sensitivity of 80%, a specificity of 66.7%, and an area under the curve of 0.82. A linear predictive model was developed for gastric volume based only on antral cross-sectional area (Volume (ml) = -327.1 + 215.2 × log (cross-sectional area) (cm2 )). We conclude that in pregnant women in the third trimester of gestation, the antral cross-sectional area correlates well with volumes ingested, and this cut-off value in the semirecumbent right lateral position discriminates high gastric volumes.
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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.
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This review applied cardiovascular principles relevant to the physiology of venous return in interpreting studies on the utility of a passive leg-raising manoeuvre to identify patients who do (responders) or do not respond to a subsequent intravenous volume challenge with an increase in cardiac output. Values for cardiac output, mean arterial and central venous pressure, and the calculated cardiovascular variables mean systemic filling pressure analogue, heart efficiency, cardiac power indexed by volume state and volume efficiency, before and after passive leg raising as well as before and after fluid volume challenge, were extracted from published studies. Eleven studies including 572 patients and 52% responders were analysed. ⋯ The scalar measure volume efficiency was higher in responders at 0.35 compared with non-responders at 0.10. Non-responders also demonstrated deteriorating heart efficiency of -15% and cardiac power of -7% when given an intravenous fluid volume challenge. The results demonstrate that the calculation of mean systemic filling pressure analogue and derived variables can identify patients likely to respond to a fluid volume challenge and provides scalar results rather than merely a dichotomous outcome of responder or non-responder.
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Randomized Controlled Trial
Recovery characteristics of patients receiving either sugammadex or neostigmine and glycopyrrolate for reversal of neuromuscular block: a randomised controlled trial.
Sugammadex more rapidly and reliably reverses rocuronium-induced neuromuscular block compared with neostigmine, but it is not known if subsequent patient outcomes, including nausea, vomiting and other aspects of recovery are modified. In this study, we compared the recovery characteristics of sugammadex and neostigmine/glycopyrrolate following reversal of neuromuscular block. This was a single-centre, randomised, blinded, parallel-group clinical trial in women undergoing elective day-surgical laparoscopic gynaecological surgery, with a standardised general anaesthesia regimen that included rocuronium. ⋯ Sedation scores at 2 h were also lower after sugammadex (median (IQR [range]) 0 (0-3 [0-10]) vs. 2 (0-4.[0-10]); p = 0.021). Twenty-four-hour recovery scores were not significantly different between groups. Reversal with sugammadex in this patient population did not reduce postoperative nausea or vomiting compared with neostigmine/glycopyrrolate.