Anaesthesia and intensive care
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Anaesth Intensive Care · Jun 2007
Stability of the strong ion gap versus the anion gap over extremes of PCO2 and pH.
The strong ion gap (SIG) is under evaluation as a scanning tool for unmeasured ions. SIG is calculated by subtracting [buffer base], which is ([A-]+[HCO3-), from the apparent strong ion difference, which is ([Na+]+[K+]+[Ca++]+[Mg++]-[Cl-]-[L-lactate]). A- is the negative charge on albumin and phosphate. ⋯ AG values were directly correlated with pH (normal: R2 = 0.51, hypoalbuminaemic: R2 = 0.65). Final AG values significantly exceeded initial values (normal blood: 15.9 (1.7) mEq/l versus 8.9 (1.8) mEq/l, P < 0.01; hypoalbuminaemic blood: 16.5 (0.8) mEq/l versus 11.8 (2.0) mEq/l, P < 0.05). We conclude that, unlike the AG, the SIG is not affected by severe respiratory acidosis and alkalosis, enhancing its utility in acid-base disturbances.
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Anaesth Intensive Care · Jun 2007
Randomized Controlled TrialImpact of bispectral index monitoring on propofol administration in patients undergoing cardiopulmonary bypass.
Propofol anaesthesia using target control infusion during cardiac surgery has become more popular recently. However, without depth of anaesthesia monitoring, the standard target concentration used may be higher than necessary to maintain adequate hypnosis during hypothermic cardiopulmonary bypass. The purpose of this study was to evaluate the effect of bispectral index monitoring on propofol administration during hypothermic cardiopulmonary bypass. ⋯ The bispectral index value during bypass was significantly lower in group C than in group B, reflecting a deeper state of anaesthesia. There was no difference in the use of inotropes, vasoconstrictors or vasodilators. Bispectral index monitoring enables a 50% reduction in propofol administration at this standard dose during hypothermic cardiopulmonary bypass.
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Anaesth Intensive Care · Jun 2007
Randomized Controlled TrialClosed-loop anaesthesia delivery system (CLADS) using bispectral index: a performance assessment study.
The development of electroencephalographic indices of anaesthetic depth has in turn generated interest in automated anaesthesia delivery systems using these as the input variable. In this paper, one patented closed loop anaesthesia delivery system (CLADS) (502/DEL/2003) is compared to manual control of propofol delivery titrated to the bispectral index (BIS). Forty ASA I-II patients undergoing elective surgery under general anaesthesia were enrolled in the study. ⋯ Smaller amounts of anaesthetic agent were required (P < 0.01) and there was faster postoperative recovery (P < 0.05). Manual delivery of propofol required the infusion rate to be changed a median of 30 times (IQR 12-45), which required considerable time and attention by the anaesthetist. In conclusion, automated delivery of propofol adjusted to the bispectral index using our CLADS was both effective and efficient as compared to manual control.
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Anaesth Intensive Care · Jun 2007
Case ReportsTranstracheal jet ventilation in management of the difficult airway.
We present the use of transtracheal jet ventilation in two uncooperative patients with a difficult airway. Although transtracheal jet ventilation is considered as a last resort option in the difficult airway algorithm, its use can be a valuable tool in selected difficult airway situations. Transtracheal jet ventilation can effectively maintain arterial oxygenation and provide extra time for attempts to intubate the trachea, either directly or fibreoptically.