Surgery
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Comparative Study
Peripheral postcapillary venous pressure: a new, more sensitive monitor of effective blood volume during hemorrhagic shock and resuscitation.
Peripheral postcapillary venous pressure (PCVP) and mixed venous oxygen saturation (SvO2 or PASO2) have been shown to be sensitive indicators of volume status and appear to reflect the adequacy of peripheral perfusion during controlled bleeding. This study demonstrates that in an open-chest dog model with controlled venous return, PCVP is closely and linearly (r2 = 0.6) correlated with cardiac output (CO). Furthermore, oxygen saturation as measured in the central venous system (CVSO2) and peripheral vein PVSO2) were found to be closely and linearly related to PASO2 (r = 0.72 to 0.99 and 0.91 to 0.98, respectively). ⋯ During resuscitation after controlled hemorrhage, the PCVP and PVSO2 accurately reflected the restoration of blood volume and were as good as CO and central saturations. Central venous and pulmonary wedge pressures both poorly reflected the return to full volume repletion (P less than 0.01). Thus, PCVP and PVSO2 seem to be reliable indices of volume status and perfusion and do not require invasive, central monitoring.
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Randomized Controlled Trial Comparative Study Clinical Trial
Hypertonic sodium lactate versus lactated ringer's solution for intravenous fluid therapy in operations on the abdominal aorta.
Fifty-eight patients who were to undergo aortic reconstruction were prospectively randomized into two groups to compare the effects of perioperative fluid replacement with isotonic and hypertonic crystalloid solutions. Blood loss was replaced with packed red blood cells, and additional fluid was given as either Ringer's lactate solution (RL, 130 mEq sodium/L, 274 mOsm/L) or a hypertonic balanced salt solution (HSL, 250 mEq sodium/L, 514 mOsm/L). Fluid was administered to maintain the cardiac filling pressure within 3 torr of the preoperative level and the cardiac output (CO) at or above the preoperative level. ⋯ Two patients in the HSL group had a persistent elevation in serum osmolarity (greater than 320 mOsm/L) during operation, for which they received RL for the balance of the resuscitation. There were no complications that could be attributed to the hypertonicity of the solution. HSL is effective for resuscitation of patients with extracellular fluid deficit and is safe provided that the serum sodium and osmolarity are monitored during periods of large volume administration.
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The intravascular clearance of type 3 Streptococcus pneumoniae was studied in Sprague-Dawley rats. One hundred animals were divided into the following five equal groups: I--splenic mobilization, II--splenectomy, III--splenectomy plus pneumococcal vaccine, IV--splenectomy plus 50,000 U of penicillin prophylaxis, V--splenectomy plus 300,000 U of penicillin prophylaxis. Bacteremia was induced by intraperitoneal injection of 10(6) type 3 S. pneumoniae. ⋯ More importantly, such immunization of asplenic animals significantly improved pneumococcal clearance compared to clearance in asplenic, nonimmunized rats (P less than 0.03). Although in both groups I and III animals S. pneumoniae organisms were effectively removed from the peripheral blood, the clearance curves are significantly different (P less than 0.01). This represents the difference between phagocytosis by the reticuloendothelial cells of the liver and those of the spleen.
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We infused hyperoncotic albumin (25 or 50 gm of a 50% solution) into patients with noncardiac pulmonary edema (adult respiratory distress syndrome [ARDS]) to evaluate its effect on the transmicrovascular flux from blood to pulmonary edema fluid of two radiotracers--111In-DTPA (mol wt 504) and 125I-human serum albumin (HSA) (mol wt 69,000). Two groups of patients were studied--one with a modest increase in permeability of the pulmonary alveolocapillary membrane to 125I-HSA (group 1) and another with a large increase in permeability to 125I-HSA (group 2). We used furosemide, when necessary, to minimize the effect of albumin infusion to increase the pulmonary microvascular hydrostatic pressure (Pmv), measured clinically as the pulmonary capillary wedge pressure (PCWP). ⋯ In individual patients, a change in the Pmv in response to albumin infusion was directly correlated with the change in flux of 111In-DTPA [group 1: delta In-DTPA (%) = 8.66 + 1.4 delta Pmv (%) r = 0.51, P less than 0.02; group 2: delta In-DTPA (%) = -3.43 + 1.6 delta Pmv (%) r = 0.67, P less than 0.01]. A change in the transmicrovascular flux of I-HSA also correlated with a change in the intravascular Starling forces in both groups. We conclude that albumin infusion in patients with ARDS will not augment the pulmonary transmicrovascular flux of low or high molecular-weight solutes when the effect of albumin to increase the Pmv is minimized; nor, however, does an increase in plasma COP significantly reduce the flux of such solutes.
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Acute arterial occlusion affecting the extremities remains a significant cause of death and limb loss. Our approach to the management of these patients has been selective, and it is based upon a clinical distinction between embolism and thrombosis. Patients with acute embolic occlusion are treated with prompt embolectomy. ⋯ Of the patients with embolism, four died (13.8%) and three required amputation (10.4%). There were six deaths (12%) among the patients with thrombosis, but eleven required amputation (22%), and in seven of these amputation was the definitive treatment. We have concluded that the selective use of surgery is an appropriate method of treatment for patients with acute thromboembolic limb ischemia.