Anesthesia and analgesia
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Anesthesia and analgesia · Jan 1996
Comparative StudyFactors associated with excessive postoperative blood loss and hemostatic transfusion requirements: a multivariate analysis in cardiac surgical patients.
The purpose of this study was to prospectively evaluate whether heparin and protamine doses administered using a standardized protocol based on body weight and activated clotting time values are associated with either transfusion of hemostatic blood products (HBPs) or excessive postoperative bleeding. Analysis using 10 multiple logistic or linear regression models in 487 cardiac surgical patients included perioperative variables that may have an association with either transfusion of HBP and/or excessive postoperative chest tube drainage (CTD). ⋯ Preoperative use of warfarin or heparin was not associated with excessive blood loss of perioperative transfusion of HBPs. In contrast to previous studies using bovine heparin, data from the present study do not support the use of reduced doses of porcine heparin during CPB.
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Anesthesia and analgesia · Jan 1996
Comparative StudyDoes age or pseudocholinesterase activity predict mivacurium infusion rate in children?
Previous studies have suggested that the mivacurium infusion rate to maintain target twitch depression is greater in children than in adults, and that there is only a limited relationship between pseudocholinesterase activity and mivacurium infusion rate in children. We therefore examined whether mivacurium infusion rates are larger in children than in adults, and whether pseudocholinesterase activity influences mivacurium infusion rate in children. In 20 children aged 1-9 yr, mechanical twitch response to ulnar nerve train-of-four stimulation was measured; concurrent data were obtained in 14 adults aged 18-58 yr. ⋯ For children, IR50 (r2 = 0.22, P = 0.038) but not IR90 (r2 = 0.11 P = 0.21) was related to pseudocholinesterase activity. Infusion rates were approximately twice as large in children as in adults. We confirm that mivacurium infusion rates are larger in children than in adults and demonstrate a relationship between pseudocholinesterase activity and infusion rates.
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Anesthesia and analgesia · Jan 1996
Comparative StudyCoronary perfusion pressure during cardiopulmonary resuscitation after spinal anesthesia in dogs.
Cardiac arrest during spinal anesthesia is a rare event, but when it does happen cardiopulmonary resuscitation (CPR) is often ineffectual. This study examines the effect of spinal anesthesia on coronary perfusion pressure (CPP) during CPR and the subsequent response of CPP to epinephrine administration. Twenty mongrel dogs were anesthetized, and randomly assigned to a spinal injection with either 0.5 mg/kg bupivacaine or with an equivalent volume of normal saline. ⋯ Epinephrine is effective in increasing CPP during CPR above the critical threshold. These data suggest that if cardiac arrest occurs during spinal anesthesia, epinephrine should be given in doses of 0.01-0.02 mg/kg IV initially and then increasing to 0.1 mg/kg IV. When this does not work, and ineffective CPR is suspected, alternative resuscitative measures should be considered.
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Anesthesia and analgesia · Jan 1996
Head rotation during internal jugular vein cannulation and the risk of carotid artery puncture.
We undertook a prospective laboratory study to examine the effect of head position on the relative positions of the carotid artery and the internal jugular vein (IJV). Volunteers (n = 12) from departmental staff, 18-60 yr of age, who had never undergone cannulation of the IJV underwent imaging of their IJV and carotid artery. With the subject in a 15 degrees Trendelenburg position, two-dimensional ultrasound images of the IJV and the carotid artery were obtained on the left and right sides of the neck at 2 and 4 cm from the clavicle along the lateral border of the sternal head of the sternocleidomastoid muscle at 0 degrees, 40 degrees, and 80 degrees of head rotation from the midline. ⋯ The IJV frequently collapses with needle insertion. This may result in puncture of the posterior wall of the vessel, and thus of the carotid artery when the two vessels overlap. To decrease this risk, the head should be kept in as neutral a position as possible, that is < 40 degrees rotation, during IJV cannulation.
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Anesthesia and analgesia · Jan 1996
Comparative StudyCoupling between local cerebral blood flow and metabolism after hypertonic/hyperoncotic fluid resuscitation from hemorrhage in conscious rats.
The effects of small volume hypertonic/hyperoncotic fluid resuscitation from hemorrhage on brain metabolism and blood flow were evaluated by autoradiographic techniques with high spatial resolution. The data were compared to fluid resuscitation with a volume equal to shed blood of isotonic 6% hydroxyethyl starch solution (HES) and a control group without hemorrhage and fluid resuscitation (n = 6 in each group). In conscious rats, volume-controlled hemorrhage for 30 min (30 mL/kg body weight, resulting in a blood loss of approximately 50% of the circulating blood volume) was followed by intravenous infusion of a hypertonic/hyperoncotic saline hydroxyethyl starch solution (HTHO; 7.5% saline/10% hydroxyethyl starch, 4.0 mL/kg body weight). ⋯ The close relationship between LCGU and LCBF observed in the control group (r = 0.95) was preserved after hemorrhage and fluid resuscitation with HTHO (r = 0.97) and HES (r = 0.96), although the LCBF-to-LCGU ratio was reset to a higher level (1.5 mL/mumol in the control group and 2.7 mL/mumol after fluid resuscitation with HTHO and HES, P < 0.05). We conclude that the increase in LCBF compensates for the reduction of arterial oxygen content to maintain cerebral oxygen delivery. Therefore, "small volume resuscitation" appears to be as effective as resuscitation with large volumes of isotonic HES in meeting the circulatory and metabolic demands of the brain tissue within the first 2 h after fluid resuscitation from hemorrhage.