Anesthesiology
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Changes in oxygen consumption (VO2) and oxygen delivery (DO2) were compared in three groups of paralyzed, sedated dogs: 1) a group (n = 5) cooled to 29 degrees C and immediately rewarmed to 37 degrees C; 2) a group (n = 5) cooled to and maintained at 29 degrees C for 24 h, and then rewarmed; and 3) a group (n = 5) maintained at 37 degrees C for 24 h. During the cooling phase, in both the acute and prolonged hypothermia animals, VO2 and DO2 decreased significantly from control values (P less than 0.05). The decrease in DO2 occurred as a result of a similar decrease in cardiac index (CI; P less than 0.05) that was associated with a significant increase in systemic vascular resistance index (SVRI; P less than 0.05). ⋯ DO2 remained below control in both groups, resulting in a significant increase in O2 extraction (P less than 0.05) and a decrease in PVO2 (P less than 0.05) in the prolonged hypothermia animals. Following rewarming administration of sodium nitroprusside returned DO2, CI, and SVRI to control values but did not increase VO2. All animals survived the study without need for inotropic support.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Comparative Study Clinical Trial
Clonidine-induced analgesia in postoperative patients: epidural versus intramuscular administration.
To compare the analgesic efficacy and plasma concentration of intramuscular (IM) versus epidural (EP) clonidine, 20 patients recovering from orthopedic or perineal surgery were randomly divided into two groups of ten. Clonidine (2 micrograms/kg) was administered epidurally in group 1 and intramuscularly in group 2. Analgesia was assessed using a visual analog scale (VAS) over a period of 6 h following clonidine administration. ⋯ Hypotension, bradycardia, and drowsiness occurred with both methods of administration. None of these effects required treatment. Thus, in postoperative patients clonidine produces similar analgesia and side effects after parenteral or EP administration.
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In patients undergoing neurosurgical procedures at high risk for venous air embolism (VAE), the presence of a right-to-left shunt adds an additional risk for paradoxical air embolism (PAE). Although this is a rare complication, it can have devastating results. The most common form of right-to-left shunt is a patient foramen ovale (PFO), which can be detected by contrast echocardiography. ⋯ Of these, four were detected by TEE. This is less than the expected incidence based on the known incidence of PFO in the general population. The usefulness of preoperative ECHO as a screening test for PFO in patients undergoing neurosurgical procedures is limited, but when a PFO is found, valuable information is acquired to help manage these patients.
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A total of 2,511 patients who received spinal anesthesia for cesarean delivery were observed for the development of postdural puncture headache (PDPH); 804 patients received a mixture of tetracaine and procaine, 942 received bupivacaine-glucose, and 765 received lidocaine-glucose. They were observed for the development of PDPH for a minimum of 72 h. ⋯ The differences between all groups was statistically significant. No differences were found in the percentage of patients who ultimately required epidural blood patch for relief of symptoms after 36 h.
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The use of the laryngeal mask airway, a new form of airway, is described in infants and young children receiving radiotherapy under general anesthesia. The laryngeal mask airway consists of a tube, at the distal end of which is attached an elliptically shaped cuff resembling a miniature face mask. ⋯ No complications occurred during use of the laryngeal mask in 25 children who received 312 anesthetics. This experience suggests that the laryngeal mask airway has a valuable role in this situation and may contribute to the safety of anesthesia.