The Journal of surgical research
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The effects of resuscitation of traumatic-hemorrhagic shock on the brain are unknown. Traumatic shock in sheep (fracture/crush injury, 2-hr hemorrhage to 40 mm Hg) was followed by resuscitation to baseline mean arterial pressure. Two groups without brain injury were resuscitated with lactated Ringer's (LR1, n = 7) or albumin (ALB1, n = 6). Focal brain injury was added in two further groups (LR2, n = 6; ALB2, n = 6). Hemodynamics, intracranial pressure (ICP), EEG, and colloid osmotic pressure (COP) were followed. Brain water (BW) and cerebral blood volume (CBV) were compared to those of controls (C, n = 7). ⋯ ICP rose in all groups. Animals without brain injury did not have increased brain water. Below are results for brain-injured animals after resuscitation (mean +/- SEM). (table; see text) Maintaining COP during initial resuscitation does not minimize cerebral edema: the effects of LR and ALB were similar in this setting. Focal brain injury causes edema but does not cause large increases in ICP with initial resuscitation.
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An experimental study was performed to determine the main site of fatigue associated with diaphragm pacing. Using 24 mature mongrel dogs, weighing 7.5 to 12.7 kg, direct phrenic nerve pacing was conducted from the right cervical area at three different respiration rates, 37 (Group 1, n = 6), 25 (Group 2, n = 6) and 12 (Group 3, n = 6) times per minute, under fixed stimulation conditions (pulse duration, 200 microseconds; frequency, 25 Hz; pulse train repetition time, 1.2 sec). Diaphragm fatigue was defined as the reduction in transdiaphragmatic pressure (Pdi) to less than or equal to 60% of the initial value. ⋯ Following administration of aminophylline, Pdi showed a significant (P less than 0.05) increase over time in all groups: 19.8 +/- 13.5% at 5 min, 23.0 +/- 13.5% at 15 min, and 16.2 +/- 14.9% at 30 min for Group 1; 23.6 +/- 11.6% at 5 min, 27.3 +/- 15.5% at 15 min, and 19.0 +/- 16.1% at 30 min for Group 2; and 29.9 +/- 21.1% at 5 min, 29.5 +/- 18.6% at 15 min, 22.3 +/- 13.8% at 30 min, and 15.5 +/- 13.4% at 45 min for Group 3. In contrast, administration of aminophylline caused no significant changes in Edi. Based upon the finding that aminophylline was significantly effective at the time of diaphragm fatigue, it is concluded that fatigue of the muscle itself constitutes one of the contributing factors for the fatigue phenomenon associated with diaphragm pacing.
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Restoration and maintenance of intravascular volume is crucial in acute pancreatitis to prevent hypotension and ensure normal organ perfusion. This study evaluated the hemodynamic and metabolic effects of adequate versus inadequate fluid replacement on the pancreas in a canine model of acute experimental pancreatitis. Bile-trypsin pancreatitis (BTP) was induced in 14 conditioned mongrel dogs. ⋯ Final changes in Qp and O2Cp from baseline were significant only in the LIR group. We conclude that inadequate crystalloid replacement after BTP results in a progressive fall in Qp and O2Cp. Vigorous fluid replacement incompletely prevents these effects.
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The biomechanical strength of skin incisional wounds of rats treated with fibrin sealant was assessed by in vitro determination of maximum tensile strength and relative failure energy. Wounds adapted without application of fibrin sealant served as control. Both types of wounds were fixed with surgical tape for the first 8 days of healing. ⋯ A similar trend was reported after 42 days of healing. In both sealed and control wounds, an increase in strain at maximum stress during healing was most pronounced in the first 8 days. After 2 days of healing the strain at maximum stress was increased in wounds treated with fibrin sealant.