Anesthesiology
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Malpractice claims filed against anesthesiologists for care involving obstetric (OB) anesthesia (n = 190) were taken from the American Society of Anesthesiologists' Closed Claims Database and compared to claims not involving OB cases (n = 1351). The most common complications in the OB claims were (percentage of all OB claims): maternal death (22%), newborn brain damage (20%), and headache (12%). In contrast, the most common complications in the nonobstetric (non-OB) group were (percentage of all non-OB claims): death (39%), nerve damage (16%), and brain damage (13%). ⋯ Claims involving general anesthesia were more frequently associated with severe injuries and resulted in higher payments than did claims involving regional anesthesia. Payments were made in a similar proportion of OB and non-OB claims (53 and 59%, respectively). For cases in which payments were made, the median payment for OB claims was significantly greater ($203,000) than for non-OB claims ($85,000; P less than or equal to 0.05).
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In dogs (n = 11) anesthetized with sodium pentobarbital (to an isoelectric EEG), the authors investigated the influence of thoracic aortic cross-clamping (AXC) on systemic hemodynamics and cerebrospinal fluid pressure (CSFP) with concurrent measurement of total brain flow (tCBF) and regional (cervical, thoracic, and lumbar) spinal cord blood flow (SCBF). The effect of phlebotomy (to control the hemodynamic consequences of AXC) on tCBF and SCBF was assessed. Radioactive microspheres were injected at four time periods in each animal: 1) at baseline; 2) with application of the AXC; 3) after phlebotomy, to reduce the proximal mean arterial pressure (MAPp) to baseline values; and 4) 2 min after removal of the AXC (mean AXC time 68 +/- 6 min). ⋯ The CSFP changed in parallel with the changes in CVP, a result suggesting that the alterations in CSFP depended on cardiac preload. The spinal cord perfusion pressure (SCPP; SCPP = MAPd - CSFP) was unchanged after phlebotomy, since both MAPd and CSFP decreased. The tCBF and cervical SCBF were unchanged when MAPp increased by 50% with application of the AXC; this indicated that autoregulation was intact.(ABSTRACT TRUNCATED AT 250 WORDS)
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Seven dogs were chronically instrumented for measurements of mean aortic blood pressure and cardiac output and for simultaneous measurements of hepatic, portal, and renal blood flows. Each animal was studied on two separate occasions, awake and during 1.2, 1.4, 1.75, and 2.0 MAC isoflurane and enflurane. Both anesthetics induced tachycardia; to a greater degree than isoflurane, enflurane lowered mean aortic blood pressure in a dose-dependent manner (-37, -45, -48, and -62% vs. -19, -25, -41, and -44%, respectively) and cardiac output (-20, -26, -41, and -48% vs. -3, -5, -11, and -15%, respectively). ⋯ Likewise, neither anesthetic significantly changed renal blood flow, except for enflurane at 2.0 MAC, which was associated with a 35% reduction. Both anesthetics led to similar systemic, hepatic, and renal vasodilations. Our data suggest that high concentrations of enflurane are associated with decreases in portal, total hepatic, and renal blood flows, most likely as a result of an anesthetic-induced cardiac depression.
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We sought to determine the percent delivery by metered-dose inhaler (MDI) of a preparation of salbutamol (albuterol) to the distal end of either pediatric-size tracheal tubes or a narrow-gauge catheter. A bench model consisting of a swivel actuator; 3.0-6.0-mm ID tracheal tubes all 16 cm in length or a 19-G (standard wire gauge) catheter; mesh filters; and a continuous flow of dry air was used. Six actuations of salbutamol (100 micrograms each) were delivered during each experiment, and each experiment was repeated nine times. ⋯ The DE of salbutamol in tracheal tubes (less than or equal to 12.3%) increased dramatically (97%; P less than 0.001) when a 19-G catheter was used. We conclude that the DE of salbutamol by MDI through 3.0-6.0-mm ID tracheal tubes is low but may be dramatically increased by actuating the canister into a 19-G distally placed catheter. Because of the increased efficiency of delivery, caution must be exercised when using a distally placed catheter to deliver MDI aerosols to patients.
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Central body temperature, which usually is well controlled, typically decreases more than 1 degree C during the 1st h of general anesthesia. This hypothermia has been attributed partially to an anesthetic-induced peripheral vasodilation, which increases cutaneous heat loss to the environment. Based on the specific heat of humans, heat loss would have to increase more than 70 W for 1 h (in a 70-kg person) to explain hypothermia after induction of general anesthesia. ⋯ Isoflurane anesthesia decreased mean arterial blood pressure approximately 20%. Average skin-surface temperature increased over 15 min to 0.5 degree C above control. Heat loss from the trunk, head, arms, and legs decreased slightly, whereas loss from the hands and feet (10.5% of the body surface area) doubled (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)