The purpose of this study was to examine the effects of the increased sympathetic activity elicited by the upright posture on blood flow to exercising human forearm muscles. Six subjects performed light and heavy rhythmic forearm exercise. Trials were conducted with the subjects supine and standing. Forearm blood flow (FBF, plethysmography) and skin blood flow (laser Doppler) were measured during brief pauses in the contractions. Arterial blood pressure and heart rate were also measured. During the first 6 min of light exercise, blood flow was similar in the supine and standing positions (approximately 15 ml.min-1.100 ml-1); from minutes 7 to 20 FBF was approximately 3-7 ml.min-1.100 ml-1 less in the standing position (P less than 0.05). When 5 min of heavy exercise immediately followed the light exercise, FBF was approximately 30-35 ml.min-1.100 ml-1 in the supine position. These values were approximately 8-12 ml.min-1.100 ml-1 greater than those observed in the upright position (P less than 0.05). When light exercise did not precede 8 min of heavy exercise, the blood flow at the end of minute 1 was similar in the supine and standing positions but was approximately 6-9 ml.min-1.100 ml-1 lower in the standing position during minutes 2-8. Heart rate was always approximately 10-20 beats higher in the upright position (P less than 0.05). Forearm skin blood flow and mean arterial pressure were similar in the two positions, indicating that the changes in FBF resulted from differences in the caliber of the resistance vessels in the forearm muscles.(ABSTRACT TRUNCATED AT 250 WORDS)
Peripheral nerve catheters are typically advanced a substantial distance into a perineural sheath, theoretically increasing the risk of catheter knotting and kinking. In this case report, we describe successful removal of a knotted fascia iliaca catheter and discuss principles of nonsurgical catheter extraction. A 64-yr-old woman with bilateral coxarthrosis presented for total hip arthroplasty under combined general/regional anesthesia. A 20-gauge fascia iliaca catheter was inserted before surgery by using a loss-of-resistance "double pop" technique. The catheter was uneventfully advanced 10 cm past the needle tip. After injection of 30 mL of 0.5% bupivacaine with 1:200,000 epinephrine and 100 microg of clonidine, general anesthesia was induced. An infusion of 0.1% bupivacaine at 20 mL/h was initiated in the recovery room for postoperative analgesia. Approximately 48 h later, resistance was encountered during catheter removal. Catheter extraction was attempted by altering patient positioning, including the supine position during which the catheter placement had occurred. Successful catheter removal was achieved by decreasing tension on the fascia lata and fascia iliaca through flexion of the hip joint and by applying firm, steady traction. The catheter was removed intact with a knot approximately 2 cm from the distal tip. We conclude that the principles for removal of entrapped peripheral catheters are not well known and may differ from those for neuraxial catheters. Patient positioning to minimize pressure and tension on the perineural soft tissues may facilitate catheter removal.
Thirty adult surgical patients admitted to the recovery room with an oral temperature less than or equal to 35.0 degrees C were randomized into two groups. Group 1 patients were covered with cotton blankets warmed to 37.0 degrees C, and group 2 patients were treated with a forced-air warming system. Mean oral temperature on admission to the recovery room was the same in both groups (34.3 degrees C). Oral temperature and the presence or absence of shivering were recorded at 15-min intervals. After application of the selected warming method, patients in group 2 were warmer at all time intervals. Mean temperatures in the forced-air heating group and in group 1 were, respectively, 34.8 degrees C and 34.3 degrees C (P less than 0.05) at 15 min; 35.0 degrees C and 34.2 degrees C (P less than 0.01) at 30 min; 35.2 degrees C and 34.5 degrees C (P less than 0.05) at 45 min; 35.8 degrees C and 34.7 degrees C (P less than 0.001) at 60 min; 36.0 degrees C and 35.0 degrees C (P less than 0.01) at 75 min; and 36.0 degrees C and 35.0 degrees C (P less than 0.01) at 90 min. The incidence of shivering was significantly greater in group 1 at 15 and 45 min. In addition, time spent in the recovery room was significantly greater in group 1 than in group 2, 156.0 min versus 99.7 min (P less than 0.003).
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