Anaesthesia and intensive care
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Anaesth Intensive Care · Apr 1999
A study to determine the optimum dose of metaraminol required to increase blood pressure by 25% during subarachnoid anaesthesia.
We studied dosage optimization for metaraminol when managing hypotension during subarachnoid anaesthesia. Twenty patients aged 53 to 84 years, were recruited. Non-invasive blood pressure (BP) and heart rate were recorded one-minutely. ⋯ Overall estimated dosage (median) to produce a 25% elevation in systolic BP was 0.5 mg (per 50 kg adult). However, individual patient responses varied (10-90th centiles = 0.23 to 0.80 mg). Thus, we now recommend a starting dose of 0.25 mg, increasing to 0.5 mg if necessary, to treat hypotension (25% decrease in systolic BP) during subarachnoid anaesthesia.
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The management of a morbidly obese parturient with a body mass index of 88 is reported. She developed asthma during the pregnancy. Lumbar epidural anaesthesia was successfully used for an elective caesarean section and tubal ligation.
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Anaesth Intensive Care · Apr 1999
Validation of Tu's cardiac surgical risk prediction index in a Western Australian population.
Tu's cardiac surgical risk prediction index for a Western Australian population was examined in a prospective observational cohort study. Risk score and outcome data were collected for 367 consecutive patients. Logistic regression analysis for Tu score prediction of hospital mortality and linear regression analysis for prediction of ICU and hospital stays were performed. ⋯ The linear regression analyses of Tu score on ICU and hospital stays showed an excellent fit (P = 0.0001). The area under the receiver-operating characteristic curve for prolonged ICU stay was 0.75. The Tu risk index is valid for a Western Australian cardiac surgical population and practice.
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Anaesth Intensive Care · Apr 1999
Physiological deadspace during normocapnic ventilation under anaesthesia.
Respiratory physiological deadspace (VDphys) during normocapnic ventilation under anaesthesia was studied in 253 patients scheduled for elective non-thoracic surgery. Subjects were ventilated with SERVO 900B ventilator using CO2 analyser 930 (Siemens-Elema Sweden) to adjust minute volume sufficient to maintain end-tidal carbon dioxide fraction (FECO2) around 5.5kPa with normocapnic confirmation using arterial blood gas analysis. VDphys was calculated using Enghoff's modification of Bohr's equation. ⋯ Males had significantly higher VDphys/mass (2.5 +/- 0.68 ml.kg) compared with females (2.2 +/- 0.54 ml/kg, P < 0.001) but significantly lower body mass index (BMI) (20.67 +/- 3.2 in males and 22.47 +/- 4.1 in females, P < 0.001). VDphys showed positive correlation with weight, height and body surface area (BSA) but VDphys/kg showed negative correlation with BMI. Multiple regression analysis produced a best fit equation for VDphys = 9.7 + 64.3 x BSA + 13.51S where S = 1 for females and 2 for males.
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Anaesth Intensive Care · Apr 1999
Comparative StudyAn audit of deaths occurring in hospital after discharge from the intensive care unit.
The aim of the study was to conduct an audit of patients who died in the ward after discharge from the intensive care unit (ICU). Clinical records of those who died in the ward following discharge between 1991 and 1997 were reviewed. Patients were retrospectively grouped according to whether death was expected, unexpected or likely to die within one year. ⋯ Of the remaining 34 patients, 65% were debilitated with more than one organ disease and 62% eventually had some treatment withdrawn on the ward. After discharge from ICU, no obvious ward treatment deficiencies were found to contribute to death. However, of those who were admitted to the ICU from the ward and who later died when back in the ward, there seemed to be avoidable events pre-ICU admission in eight (36%) patients, some of which may have contributed to the later death of the patient.