Anesthesiology
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Biography Historical Article
Robert Liston's letter to Dr. Francis Boott: its reappearance after 135 years.
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Avoidance of ketamine has been recommended in children with pulmonary hypertension or with limited right ventricular reserve, despite absence of data about the effects of ketamine on pulmonary vascular resistance (PVR) in children. Ketamine has been associated with increased PVR in studies of adults; in these studies adults were spontaneously breathing through unprotected airways, despite ketamine's known effects of ventilatory depression and partial loss of airway. ⋯ Results did not differ in infants receiving diazepam sedation. The authors conclude that ketamine has little effect on baseline hemodynamics in mildly sedated infants whose airway and ventilation are maintained; in particular, PVRI is little changed by ketamine administration in ventilated infants with either normal or increased baseline PVRI.
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Radionuclide cardiography with 99mTc-labeled erythrocytes was carried out in three different studies comprising 20 female patients without heart or lung diseases. Left ventricular ejection fraction (LVEF) and other hemodynamic variables were measured immediately before and during induction of anesthesia (thiopental, N2O/O2, succinylcholine, laryngoscopy + oral intubation, halothane). In study 1, serial measurements of LVEF, left ventricular volume, and derived variables were obtained by gamma camera in seven patients using 3-min sampling periods. ⋯ This decrease was accompanied by an increase in end-systolic volume and a decrease in the ratio: systolic cuff pressure/end systolic volume, whereas end-diastolic volume and cardiac index remained unchanged. In the nuclear stethoscope studies, LVEF decreased both after thiopental and after intubation, in study 2 from 0.68 to 0.38 and from 0.53 to 0.41, respectively; in study 3 from 0.69 to 0.53 and from 0.57 to 0.44, respectively. Our observation, in healthy, female individuals, provide an impetus for further noninvasive radionuclide studies during anesthesia in patients with cardiovascular disease.