Anaesthesia and intensive care
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Anaesth Intensive Care · Dec 2007
Clinical TrialUSCOM (Ultrasonic Cardiac Output Monitors) lacks agreement with thermodilution cardiac output and transoesophageal echocardiography valve measurements.
The USCOM (Ultrasonic Cardiac Output Monitors) device is a non-invasive cardiac output monitor, which utilises transaortic or transpulmonary Doppler flow tracing and valve area estimated using patient height to determine cardiac output. We evaluated USCOM against thermodilution cardiac outputs and transoesophageal echocardiography valve area measurements in 22 ASA PS4 cardiac surgical patients. Data collection commenced following pulmonary artery catheter insertion, with cardiac output measurements repeated after sternotomy closure. ⋯ The USCOM estimates of valve area based on height showed poor correlation with the echocardiographic measurements of aortic and pulmonary valves (r = 0.57 and r = 0.17, respectively). It was concluded that USCOM showed poor agreement with thermodilution. The estimated valve area was identified as one source of error.
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Anaesth Intensive Care · Dec 2007
Case ReportsThe management of a super morbidly obese parturient delivering twins by caesarean section.
A super morbidly obese (230 kg, body mass index 76 kg/m2) patient presented to our service for a planned elective caesarean section for twin delivery. She subsequently underwent a non-elective caesarean section after normal working hours under combined spinal epidural anaesthesia with invasive monitoring. Complex cases such as this, especially in the obstetric setting, require thorough multidisciplinary planning, communication and expertise but can be safely and successfully performed in dedicated stand-alone centres.
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Anaesth Intensive Care · Dec 2007
Propofol-induced changes in myoplasmic calcium concentrations in cultured human skeletal muscles from RYR1 mutation carriers.
Malignant hyperthermia is a pharmacogenetic disorder caused by autosomal dominant mutations in the ryanodine receptor type 1 gene. Propofol has been reported as a safe anaesthetic for malignant hyperthermia susceptible patients but has not been tested on cultured cells from patients with the ryanodine receptor type 1 mutation. The aim of this study was to determine whether propofol could trigger abnormal calcium fluxes in human myotubes isolated from malignant hyperthermia susceptible patients harbouring the native ryanodine receptor type 1 mutation. ⋯ The half-maximal activation concentrations (EC50) for propofol from patients 1 and 2 were 181.1 and 420.5 microM, respectively. Increases in calcium concentrations in response to propofol dosage were limited to doses at least 100-fold greater than those used in clinical settings. These observations correlate well with clinical observations that propofol does not trigger malignant hyperthermia in susceptible humans.
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Anaesth Intensive Care · Dec 2007
Perioperative complications in patients with drug-eluting stents: a three-year audit at Geelong Hospital.
Drug-eluting stents are a recommended treatment for lesions in the coronary arteries. Stent insertion requires the patient remain on anti-platelet medication for a minimum of six months after insertion. A serious consequence of ceasing anti-platelet medication is late stent thrombosis leading to myocardial infarction in the territory of the drug-eluting stent. ⋯ The risk of myocardial infarction when clopidogrel is stopped prior to surgery is 20%, if alternative anti-thrombotic prophylaxis is not used. This risk persists beyond one year after insertion of drug-eluting stents. Some treatments appear to be effective in reducing the risk of myocardial infarction.
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Anaesth Intensive Care · Dec 2007
Case ReportsSupplemental jet ventilation in conscious patients following major oesophageal surgery.
Intensive care unit patients are at particular risk of respiratory failure after major abdominal surgery. Non-invasive ventilation or application of continuous positive airway pressure through a face mask may stabilise respiratory function and avoid the need for endotracheal re-intubation. However; there are various contraindications to non-invasive ventilation and/or tracheal re-intubation, such as recent oesophageal anastomosis, anastomotic leakage or tracheal stenting for tracheo-oesophageal fistula. A specific management strategy consisting of continuous intratracheal jet ventilation to support spontaneous respiratory function is described in two patients with contraindications to non-invasive ventilation or mask continuous positive airway pressure after major oesophageal surgery.