Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2002
Needle electrodes can be used for bispectral index monitoring of sedation in burn patients.
We present the results of a study examining the agreement of bispectral index values obtained using original sensor and subdermal needle electrodes in burn patients. Both types of electrodes can be used interchangeably to monitor depth of sedation.
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Anesthesia and analgesia · Dec 2002
Influence of rate and volume of infusion on the kinetics of 0.9% saline and 7.5% saline/6.0% dextran 70 in sheep.
We examined whether volume kinetic variables obtained during infusion of a short bolus of 0.9% saline (NS) or 7.5% saline/6.0% dextran 70 (HSD) predict the dilution-time curve resulting from a 20-min infusion of the same fluid. Each of six conscious, splenectomized sheep (mean body weight, 36 +/- 3 kg), on 4 different days, in a random order, received each of 4 IV boluses: NS at a rate of 1.2 mL. kg(-1). min(-1) over 5 min or 20 min or 4.0 mL/kg of HSD over 2 min or 20 min. One, 2, and 3-volume kinetic models were fitted to the dilution of the arterial hemoglobin concentration and the urinary excretion as sampled during 180 min. The maximum dilution of arterial plasma at the end of the 5-min and 20-min infusions of NS was approximately 10% and 22%, respectively, and after the 2-min and 20-min infusions of HSD, maximum dilution was 24% and 21%, respectively. The median absolute performance error was virtually identical when the mean variable estimates from the 5-min infusion of NS were used to predict the individual dilution-time curves of the 5-min (mean, 0.027 dilution units) and 20-min (mean, 0.027) infusions and when the 2-min infusion of HSD was used to predict the dilution during the individual 2-min (mean, 0.050) and 20-min infusions (mean, 0.047). Computer simulations indicated that the difference at the end of infusion between the volume effects of NS and HSD is larger after longer infusions. We concluded that the volume kinetic variables obtained during a short infusion can be used to predict the outcome of a longer one, even if the longer infusion also delivers a larger volume. ⋯ Kinetic analysis of a short infusion of 7.5% saline/6% dextran or 0.9% saline accurately predicts the effects of a longer infusion of the same volume (7.5% saline/6% dextran) or of a larger volume (0.9% saline).
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Anesthesia and analgesia · Dec 2002
Vasopressor response in a porcine model of hypothermic cardiac arrest is improved with active compression-decompression cardiopulmonary resuscitation using the inspiratory impedance threshold valve.
During normothermic cardiac arrest, a combination of active compression-decompression (ACD) cardiopulmonary resuscitation (CPR) with the inspiratory threshold valve (ITV) significantly improves vital organ blood flow, but this technique has not been studied during hypothermic cardiac arrest. Accordingly, we evaluated the hemodynamic effects of ACD + ITV CPR before, and after, the administration of vasopressin in a porcine model of hypothermic cardiac arrest. Pigs were surface-cooled until their body core temperature was 26 degrees C. After 10 min of untreated ventricular fibrillation, 14 animals were randomly assigned to either ACD CPR with the ITV (n = 7) or to standard (STD) CPR (n = 7). After 8 min of CPR, all animals received 0.4 U/kg vasopressin IV, and CPR was maintained for an additional 10 min in each group; defibrillation was attempted after 28 min of cardiac arrest, including 18 min of CPR. Before the administration of vasopressin, mean +/- SEM common carotid blood flow was significantly higher in the ACD + ITV group compared with STD CPR (67 +/- 13 versus 26 +/- 5 mL/min, respectively; P < 0.025). After vasopressin was given at minute 8 during CPR, mean +/- SEM coronary perfusion pressure was significantly higher in the ACD + ITV group, but did not increase in the STD group (29 +/- 3 versus 15 +/- 2 mm Hg, and 25 +/- 1 versus 14 +/- 1 mm Hg at minute 12 and 18, respectively; P < 0.001); mean +/- SEM common carotid blood flow remained higher at respective time points (33 +/- 8 versus 10 +/- 3 mL/min, and 31 +/- 7 versus 7 +/- 3 mL/min, respectively; P < 0.01). Without active rewarming, spontaneous circulation was restored and maintained for 1 h in three of seven animals in the ACD + ITV group versus none of seven animals in the STD CPR group (not significant). During hypothermic cardiac arrest, ACD CPR with the ITV improved common carotid blood flow compared with STD CPR alone. Moreover, after the administration of vasopressin, coronary perfusion pressure was significantly higher during ACD + ITV CPR, but not during STD CPR. ⋯ New strategies are needed to improve the efficiency of cardiopulmonary resuscitation (CPR) in hypothermic cardiac arrest. Active compression-decompression CPR with the inspiratory threshold valve improved carotid blood flow (and coronary perfusion pressure with vasopressin) compared with standard CPR.
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Anesthesia and analgesia · Dec 2002
Case ReportsNear tracheal extubation because of edema of the face and tongue.
Edema of the face and tongue can cause migration of the endotracheal tube out of the trachea. The present case illustrates the importance of preventing this potentially disastrous complication because reintubation might be impossible when the edema is severe.
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Anesthesia and analgesia · Dec 2002
The use of neuromuscular blocking drugs in adult cardiac surgery: results of a national postal survey.
Available data suggest that the choice of neuromuscular blocking drugs (NMBDs) can influence early clinical recovery of the fast-track cardiac surgical patient. The aim of this study was to use a survey tool to determine practice patterns of anesthesiologists for the use of NMBDs in the cardiac surgical setting. We mailed a survey to one third of the 3295 active members of the Society of Cardiovascular Anesthesiologists. A follow-up letter and survey were sent to each individual who did not respond to the initial mailing. After the second mailing, 459 surveys were returned, yielding a response rate of 43%. Pancuronium was listed as the primary NMBD used in the majority of patients undergoing cardiopulmonary bypass (69%) and off-pump (41%) procedures. Only 28% of respondents routinely used a peripheral nerve stimulator to monitor neuromuscular blockade in the operating room. Residual neuromuscular blockade was routinely reversed before tracheal extubation by only 9% of cardiac anesthesiologists. This survey demonstrates that long-acting NMBDs are often administered to fast-track cardiac patients. Peripheral nerve stimulator monitoring is rarely used in the operating room or intensive care unit, and reversal drugs (anticholinesterases) are infrequently administered in the postoperative period. ⋯ This postal survey of cardiac anesthesiologists demonstrates that long-acting muscle relaxants are frequently administered to fast-track cardiac surgical patients. Neuromuscular blockade is rarely monitored or reversed in this patient population.