Pericardial tamponade: a critical determinant for survival following penetrating cardiac wounds

Previous studies have emphasized injury mechanism, wound site, and presenting vital signs as critical determinants for survival following penetrating cardiac injury. Our experience suggests pericardial tamponade is another crucial factor and is the basis for this study. Prognostic features were reviewed in 100 consecutive, unselected patients with acute cardiac injuries. Mechanism was stab wound in 57, and gunshot injury in 43. Location included right ventricle in 55, left ventricle in 49, right atrium in 16, and left atrium in seven. Overall salvage was 31%,; 27 (47%) of 57 stab wounds, four (9%) of 43 gunshot wounds, 22 (49%) of 45 right, and nine (23%) of 39 left heart wounds. The presence or absence of pericardial tamponade was documented in 77 patients. Patients with tamponade had a survival of 73% (24/33) compared to 11% (5/44) in those without its protective effect. The presence of tamponade improved survival (p less than 0.05) following stab injuries (77% vs. 29%), gunshot wounds (57% vs. none), right heart wounds (79% vs. 28%), left heart injuries (71% vs. 12%), and overall in patients arriving with vital signs (96% vs. 50%). Multivariant discriminant analysis by logistic regression demonstrated cardiac tamponade was a critical independent factor in patient survival, and suggested that it may be more influential than presenting vital signs in determining outcome.     

Trends in long-term survival following liver resection for hepatic colorectal metastases

OBJECTIVE: To examine trends in outcomes of patients undergoing resection at a single tertiary care referral center over a 16-year period. SUMMARY BACKGROUND DATA: Hepatic resection is considered the treatment of choice in selected patients with colorectal metastasis confined to the liver. Although a variety of retrospective studies have demonstrated improvements in short-term outcomes in recent years, changes in long-term survival over time are less well-established. METHODS: Data from 226 consecutive patients undergoing potentially curative liver resection for colorectal metastases between 1984 and 1999 were analyzed. Actuarial survival rates related to prognostic determinants were analyzed using the log-rank test. RESULTS: The median survival for the entire cohort was 46 months, with 5- and 10-year survival rates of 40% and 26% respectively. Ninety-three patients operated on between 1984 and 1992 were found to have an overall survival of 31% at 5 years, compared to 58% for the 133 patients operated on during the more recent period (1993-1999). Both overall and disease-free survival were significantly better in the recent time period compared with the earlier period on both univariate and multivariate analyses. Other independent factors associated with improved survival included number of metastatic tumors < or = 3, negative resection margin, and CEA < 100. Comparisons were made between time periods for a variety of patient, tumor and treatment-related factors. Among all parameters studied, only resection type (anatomical versus nonanatomical), use of intraoperative ultrasonography, and perioperative chemotherapy administration differed between the early and recent time periods. CONCLUSIONS: Long-term survival following liver resection for colorectal metastases has improved significantly in recent years at our institution. Although the reasons for this survival trend are not clear, contributing factors may include the use of newer preoperative and intraoperative imaging, increased use of chemotherapy, and salvage surgical therapy.     

Preshunt liver function remains the prominent determinant of survival after portasystemic shunting

BACKGROUND: Forty-five years after the development of the Child classification, we sought to determine if hepatic function is still a primary determinant between short-term and long-term survival after portasystemic shunting. METHODS: One hundred forty-six patients underwent small-diameter prosthetic H-graft portacaval shunting (HGPCS). The patients were stratified into 2 groups: those surviving less than 5 years and those surviving more than 5 years. Preoperative data determined Child class and model for end-stage liver disease (MELD) score. RESULTS: Ninety-four (64%) patients were short-term and 52 (36%) patients were long-term survivors. No significant differences in the cause of cirrhosis, presence of ascites, encephalopathy, or emergency operations were noted between short- and long-term survivors. Preshunt MELD scores were significantly greater with short-term survivors, although actual survival was superior to predicted survival by MELD. Child class was inferior for short-term survivors. Child class and MELD score significantly correlated with survival after portasystemic shunting. CONCLUSIONS: Long-term survival after HGPCS is possible even with severe hepatic dysfunction; however, actual survival is superior to predicted survival. Hepatic dysfunction, as denoted by Child class and MELD, still remains a primary determinant of survival after portasystemic shunting.     

Isometric contractile function recovery following tourniquet ischemia

The purpose of this study was to document the recovery of isometric contractile function following tourniquet ischemia. Male Wistar rats (N = 27) were subjected to unilateral hindlimb tourniquet ischemia of 0 hr (control, N = 6), 1 hr (N = 5), 2 hr (N = 5), 3 hr (N = 5) and 4 hr (N = 3). Following a 2-week recovery period, isometric force measurements were made from both gastrocnemii of each rat with the contralateral limb acting as the control side. Each muscle was analyzed for maximal twitch (Pt, N/g), maximal rate of rise of twitch tension (DP/dt, N/sec), time to peak tension (TPT, msec), half relaxation time (RT 1/2, msec), maximal tetanus (P0, N/g, at 100 Hz), and fatigue (Burke Fatigue Protocol). Pt, P0, and DP/dt were significantly different from control values (P less than 0.05) for all hours of tourniquet ischemia. A strong negative correlation (P less than 0.001) was found for twitch (R = -0.84), tetanus (R = -0.78), and maximal rate of force development (R = -0.83) with respect to increasing hours of ischemia. The recovery of isometric twitch and tetanic function following tourniquet ischemia is inversely related to the ischemic interval. This study quantified the relationship between muscle ischemia and recovery of function following a 2-week interval and stresses the functional physiological changes which occur in skeletal muscle following tourniquet ischemia.     

Reticuloendothelial function in human renal allograft recipients.

The phagocytic and metabolic functions of the reticuloendothelial system (RES) were determined, by measuring the plasma clearance rate of 125I-labelled microaggregated human serum albumin and the increase in plasma metabolites of this test substance, in patients with chronic renal failure and in renal transplant recipients at different times after transplantation. All transplant recipients received triple immunosuppressive therapy consisting of azathioprine, corticosteroids, and antilymphocyte globulin. The intravascular clearance of microaggregated albumin was significantly depressed in patients when tested at 1 to 12 days (P less than 0.001), 1 to 4 months (P less than 0.02), and 6 to 9 months (P less than 0.001) after transplantation compared to pretransplantation. The 1- to 3-year transplant survivors had a normal RES phagocytosis. Furthermore, the metabolic RES function in all groups of transplant recipients except the group of patients tested at 1 to 4 months after transplantation was significantly impaired compared to pretransplantation. Administration of antilymphocyte globulin and extremely high daily doses of steroids were probably responsible for the significant depression in the RES functions recorded immediately post-transplantation. The further development of the phagocytic ability of the RES was shown to be correlated to the cumulative dose of steroids given over the last 12 months. The azathioprine regime seemed to have no influence on the RES functions.     

Experimental study on functional and morphological restoration following hepatic ischemia

Restoration of damaged hepatocytes after ischemia was studied functionally and morphometrically in a rat model with partial hepatic vascular occlusion. In 30 min occlusion group (n = 35), ATP (mols/mg of protein) dropped down to nearly zero, but returned to the pre-ischemic level within 6 hours after reperfusion. The number of mitochondria (Mt)/unit area of cytoplasm (N/beta m2) increased to 1.41 times of the pre-ischemic value. Simultaneously, the area of single Mt decreased to 2/3 of the pre-ischemic value. Cellular necrosis and subsequent fibrosis were slight, not different from those of the controls. In 60 min occlusion group (n = 35), it took 14 days for ATP to return to the pre-ischemic level. An increase in the number of Mt and reduction in the Mt area, were slight compared with 30 min occlusion group. In contrast, necrosis and subsequent fibrosis markedly developed with a concomitant increase in lysosomes. In conclusion, it was suggested that, in 30 min of ischemia, active division of Mt, which is a compensatory mechanism of Mt reduced the degree in ischemic damage of hepatocytes, in contrast, in 60 min ischemia, division of mitochondria was limited, causing delayed recovery of ATP and severe necrotic change of hepatocytes.     

Reticuloendothelial and mesangial function in murine immune complex glomerulonephritis.

The function of the mesangial and reticuloendothelial system was evaluated in normal mice and in mice with nephritis induced by lymphocytic choriomeningitis (LCM) virus infection. Heat-aggregated human immunoglobulin (AlgG) and colloidal carbon served as traceable materials which could be detected in animals' blood and tissues. LCM virus-infected proteinuric (LCM-P) mice, as compared to normal mice or LCM-infected nonproteinuric (LCM) mice, had greater accumulation of AIgG in their glomeruli at all times of examination following i.p. injection of AIgG. The removal rate of AIgG from the kidney, however, was the same in normal and LCM-P mice, indicating an unimpaired mesangial clearing system. This suggested that other mechanisms were responsible for the increased glomerular accumulation of AIgG in LCM-P mice. Reticuloendothelial function was examined directly by i.v. injection of AIgG or colloidal carbon. The data demonstrate that in this model of immune complex glomerulonephritis, colloidal material tested was removed from the blood at a slower rate than it was in normal mice. Deficient clearance of endogenous blood-borne immune complex-like material may be one of the factors playing a role in the accumulation of immune complex-like material in the glomeruli of these nephritic animals.     

Liver ischemia for hepatic resection: where is the limit?

BACKGROUND. A consecutive series of 50 patients who submitted to 53 hepatic resections with use of continuous normothermic liver ischemia is reported. METHODS. Portal triad clamping has been used in 28 cases, with associated inferior vena caval clamping above and below the liver (hepatic vascular exclusion) in 25 patients. The size of the tumor required major hepatic resection in 38 cases (71.7%). Malignant tumors (83%) were the most common indication for liver resection. Patients were placed in three groups according to the duration of liver ischemia: group A, less than 30 minutes (9 patients); group B, 30 to 60 minutes (29 patients); and group C, 60 or more (15 patients). RESULTS. No differences in mortality rates (5.7% in the entire series and 0% in group C) and morbidity rate could be shown. No significant difference was found in postoperative liver test results, and no persistent alteration remained thereafter. Liver biopsy at 6 and 12 months after operation did not reveal any chronic damage. Liver capability to regenerate was maintained as documented by postoperative computerized tomography scan or magnetic resonance imaging. CONCLUSIONS. Because interruption of hepatic blood flow in normothermia is safe for at least 60 minutes (up to 85 minutes in this study), vascular clamping is recommended for hazardous liver resections to minimize blood loss, which appears to be the main factor of death and morbidity.