Surgery
-
The present study compares the hemodynamic effectiveness of closed-chest cardiac massage (CCCM) with closed subdiaphragmatic massage (CSDM) and four open transdiaphragmatic cardiac massage techniques during cardiac arrest with an open abdomen. In 10 dogs CCCM resulted in the lowest cardiac index (CI), mean arterial pressure (MBP), and carotid blood flow (CBF) of all cardiac massage techniques tested. CSDM was not statistically superior to CCCM in the dog (p greater than 0.05) but did result in a 23% increase in CI and a 54% increase in CBF. ⋯ In three cadaveric renal donors, all four open transdiaphragmatic techniques and CSDM were noted to be equal to or superior to CCCM. Three patients have been successfully resuscitated with diaphragmatic cardiac massage techniques for cardiac arrest while undergoing abdominal operations. These studies reveal that all subdiaphragmatic or transdiaphragmatic techniques for cardiac massage are hemodynamically equivalent to or superior to the standard CCCM without such complications as fractured ribs and should be considered the treatment of choice for cardiac arrest in the patient with an open abdomen.
-
Wound infections are a major problem in burned patients. To determine the rate of wound infection associated with initial wound size and the amount of open full-thickness wound, we prospectively studied all patients admitted within 1 week of burn injury during a 2-year period using weekly wound cultures. Wounds were treated with topical silver sulfadiazine and occlusive dressings. ⋯ Wound infections occurred during 47 of 96 patient weeks (49.0%) when the current full-thickness wound was greater than 10% BSA. The infection rate decreased to 76 of 594 (12.8%) and 17 of 833 patient weeks (2.0%) when the remaining full-thickness wound was reduced to 1% to 10% and less than 1% BSA, respectively (p less than 0.05). Early wound closure would appear to reduce the risk of serious wound infections, especially in patients with full-thickness burns.
-
The body clearance of 10 plasma amino acids (AA) was determined from the rate of compared muscle-released AA and AA administered by infusion of total parenteral nutrition (TPN) compared to their estimated extracellular (ECW) pool in patients with multiple trauma with (n = 10) or without (n = 16) sepsis at 8-hour intervals. In both nonseptic and septic trauma, increasing TPN increased the mean clearance rate of all infused AA. When the individual AA clearance rates were normalized by the total AA infusion rate, regression-covariance analysis revealed that patients with sepsis had relatively impaired clearances of alanine (p less than 0.01) and methionine, proline, phenylalanine, and tyrosine p less than 0.05 for all). ⋯ At any AA infusion rate, compared with surviving patients with sepsis (p less than 0.05), patients who developed fatal multiple organ failure syndrome (MOFS) showed increased clearances of all BCAA with further impaired clearance of tyrosine. The clearance ratio of leucine/tyrosine was increased in MOFS at any AA infusion rate (p less than 0.0001), was an indicator of severity, and, if persistent, was a manifestation of a fatal outcome. Because tyrosine metabolism occurs almost entirely in the liver while leucine can be utilized by viscera and muscle, these data suggest early and progressive septic impairment of the pattern of hepatic uptake and oxidation of AA with a greater body dependence on BCAA, especially leucine, as septic MOFS develops.
-
The relative merits of adding a "pulsatile" component to flow during cardiopulmonary bypass (CPB) has long generated controversy, the resolution of which has been hampered by lack of quantification of the "pulsatility" delivered by different devices. The present experimental series had two goals: to quantify the "pulsatility" of blood flow during CPB in terms of pulse rate and pulsatility index (PI) and to examine which aspects of a "pulsed flow" provide clinical benefits. A flow waveform can be expressed in terms of its baseline rate and its PI, the sum of the square of its harmonics components divided by the square of the mean flow. ⋯ The results indicated that a combination of a minimum PI of 1.88 and a minimum rate of 80 bpm were necessary to significantly reduce lactate production as compared with roller pump perfusion. Thus the same mean flow can have very different physiologic effects depending on how it is delivered. This quantification method permits direct comparison of different "pulsatile waveforms" and provides a means for identification of optimal pulsatile flow.
-
Complement activation by the alternate pathway has been implicated in the pathophysiology of cardiopulmonary bypass (CPB), and laboratory studies suggest that the complement cascade may be activated by the protamine-heparin complex. To determine if the administration of protamine to patients receiving heparin activates complement, we studied 100 patients undergoing CPB by assaying levels of C3a and C4a (classic pathway) at regular intervals before and after protamine administration. In group I (90 patients), protamine was given at the usual interval (median 5 minutes) after CPB. ⋯ Corresponding results from C3a analysis before and after protamine administration confirmed the activation of complement cascade. Our study provides the first clinical evidence that the protamine-heparin complex activates complement via the classic (C4a) pathway. The hemodynamic effects of protamine after CPB may be related to complement activation.