British journal of anaesthesia
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The aim of this study was to validate measurements of intraoperative left ventricular (LV) area by transoesophageal echocardiography against simultaneous measurements of LV volume by conductance catheter (CC) in cardiac surgical patients with normal systolic LV function. Echo area was compared with CC volume during steady state and during acute changes of pre- and afterload by partial clamping of the inferior vena cava and the ascending aorta in eight patients scheduled for coronary artery bypass grafting. ⋯ Intraoperative area measurements with transoesophageal echocardiography in cardiac surgical patients with normal systolic LV function show good correlation with CC volume measurements under steady-state conditions. During acute unloading by vena cava occlusion, the resulting small end-systolic echo area measurements differ significantly more from CC volume measurements than during acute increase in afterload by aortic occlusion.
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Comparative Study
Is obstructive sleep apnoea a rapid eye movement-predominant phenomenon?
Obstructive sleep apnoea (OSA) is thought to be worse during rapid eye movement (REM) sleep. REM rebound in the late postoperative period can follow the REM suppression shown to occur after some types of surgery. This is thought to worsen nocturnal episodic hypoxaemia, leading to greater cardio-respiratory risk. ⋯ While a small number clearly desaturate much more during REM, the majority do not. Thus, postoperative REM rebound may worsen OSA in some patients, but in many it may do otherwise. The implications of postoperative sleep disturbance are therefore likely to be more complex than previously suggested.
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Comparative Study
Resistance of laryngeal mask airway and tracheal tube in mechanically ventilated patients.
We compared the airflow resistance of 7.5 and 8.5 mm internal diameter (i.d.) endotracheal tubes (ETTs) with that of a size 4 laryngeal mask airway (LMA). We thought that any difference in the resistance of the devices alone might be offset by the resistance of the larynx. Sixteen adult ASA physical status I and II patients (14 males, two females) undergoing general anaesthesia were anaesthetized and paralysed with intravenous propofol, ketamine and vecuronium. ⋯ Greater resistance occurred in two patients with a central LMA position and unobstructed view of the glottis and in one patient with marked lateral deviation. In conclusion, there is no clinically relevant difference between the resistance of a size 4 LMA plus that of the larynx and that of an 8.5 mm i.d. ETT.
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Myotonic dystrophy, a rare genetic disorder, may pose a serious problem to the anaesthesiologist due to muscular and extramuscular involvement. Thirteen patients, median age 21 yr were anaesthetized by continuous propofol infusion, fentanyl, atracurium and N2O to evaluate this combination in myotonic dystrophy. Intraoperatively, neither exaggerated reactions nor haemodynamic instability was observed. ⋯ Only two patients complained of nausea and vomiting. Similarly, muscular hypertonia and shivering were not observed. We conclude that the combination of continuous propofol infusion and fentanyl was a successful anaesthetic technique in these young myotonic dystrophy patients undergoing peripheral surgery.