Brian J. Rowlands

Lower limb ischemia-reperfusion injury triggers a systemic inflammatory response and multiple organ dysfunction.

Restoration of blood flow to an acutely ischemic lower limb may, paradoxically, result in systemic complications and unexpected mortality. We investigated the effect of acute ischemia-perfusion of the lower limb on cytokine production and end organ function. Plasma concentrations of tumor necrosis factor-alpha (TNF) and interleukin-6 (IL-6) were determined in five groups of male Wistar rats: control, 3 hours of bilateral hind limb ischemia alone, and 3 hours of bilateral hind limb ischemia followed by 1 hour, 2 hours, or 3 hours of reperfusion, respectively. In a second experiment, the effect of lower limb ischemia-reperfusion on remote organs (lung, liver, and kidney) was assessed biochemically and histologically. There was a significant increase in plasma concentrations of TNFin plasma of animals subjected to 3 hours of bilateral hind limb ischemia followed by 1 hour of reperfusion, 40.1 4.4 pg/ml, when compared with controls, 22.6 4.4 pg/ml, or animals in the ischemiaalone group, 16.3 5.2 (p < 0.05). Plasma concentration of IL-6 increased progressively and significantly in animals subjected to bilateral hind limb ischemia followed by 1 hour of reperfusion, 720 107 pg/ml; 2 hours of reperfusion, 1987 489 pg/ml; or 3 hours of reperfusion, 6284 1244 (p < 0.0001), compared with controls, 104 43 pg/ml; or animals in the ischemia-alone group, 140 55 pg/ml. In the study comparing portal and systemic concentrations of IL-6, systemic concentrations of IL-6, 967 184 pg/ml were significantly higher than those in the portal circulation 577 127 pg/ml (p < 0.05). There was a significant increase in plasma concentrations of urea, creatinine, aspartate transaminase, alanine transaminase, and lactic dehydrogenase in reperfused animals compared with controls (p < 0.001). Morbidity and mortality following reperfusion of the acutely ischemic limb may be a manifestation of multiple organ dysfunction caused by a systemic inflammatory response triggered by reperfusion of the ischemic extremities. Reperfusion of the acutely ischemic limb may, paradoxically, lead to systemic complications that account for significant morbidity and mortality [1–5]. We have previously reported that lower limb ischemia-reperfusion injury alters intestinal structure and permeability [6]. In a subsequent study using the same model, we found that reperfusion of the acutely ischemic limb is associated with endotoxemia in the absence of bacterial translocation [7]. On reaching the circulation, endotoxin can initiate a cascade of events that may lead to sepsis syndrome and in some cases septic shock and multiple organ dysfunction syndrome (MODS) [5–8]. Endotoxin stimulates cellular targets such as monocytes, macrophages, neutrophils, and endothelial cells to produce a variety of inflammatory mediators [9]. Although inflammation is an important immune response vital to the host survival following various forms of injury, uncontrolled production and release of cytokines and other pro-inflammatory mediators following trauma and major surgery may lead to systemic inflammatory response syndrome (SIRS) and MODS [10]. Cytokines can modulate cell function both in the cell of origin (autocrine effect) and neighboring cells (paracrine effect) [11]. In addition, cytokines can circulate to affect different parts of the body in an endocrine fashion. Cytokines can promote neutrophil adherence, by stimulating both endothelial cells and neutrophils, and mediate acute vascular injury and increased vascular permeability [12, 13]. Of particular interest are the cytokines tumor necrosis factor (TNF) and interleukin-1-beta (IL-1 ), which are believed to be the primary mediators of SIRS [14–16], and interleukin-6 (IL-6), which is a secondary mediator responsible for the acute phase protein response [17–19]. The purpose of this study was to determine whether lower limb ischemia-reperfusion is associated with a systemic inflammatory response and, secondly, to determine the effect of acute lower limb ischemia-reperfusion on remote organs (lung, liver, and kidney) structure and function in a rat model. Materials and Methods

Combined Antioxidant Therapy Reduces Pain and Improves Quality of Life in Chronic Pancreatitis

Patients with chronic pancreatitis (CP) typically suffer intractable abdominal pain that is resistant to most analgesic strategies. Recent research indicates that the pain of CP may be in part due to oxygen free radical induced pancreatic damage. Using a randomized, double-blind, placebo-controlled crossover trial, we evaluated the efficacy of a combined antioxidant preparation in the management of CP. Patients with confirmed chronic pancreatitis (N = 36) were randomized to receive treatment with either Antox, which contains the antioxidants selenium, betacarotene, L-methionine, and vitamins C and E, or placebo for 10 weeks. Each group of patients then switched to receive the alternative treatment for a further 10 weeks. Markers of antioxidant status were measured by blood sampling, whereas quality of life and pain were assessed using the SF-36 questionnaire. Nineteen patients completed the full 20 weeks of treatment. Treatment with Antox was associated with significant improvements in quality of life in terms of pain (+17 antioxidant vs. -7 placebo), physical (+9 vs. -3) and social functioning (+8 vs.-7), and general health perception (+10 vs. -3). We conclude that treatment with antioxidants may improve quality of life and reduce pain in patients suffering from chronic pancreatitis.

Dilution and redistribution effects of rapid 2-litre infusions of 0.9% (w/v) saline and 5% (w/v) dextrose on haematological parameters and serum biochemistry in normal subjects: a double-blind crossover study

Although hypoalbuminaemia after injury may result from increased vascular permeability, dilution secondary to crystalloid infusions may contribute significantly. In this double-blind crossover study, the effects of bolus infusions of crystalloids on serum albumin, haematocrit, serum and urinary biochemistry and bioelectrical impedance analysis were measured in healthy subjects. Ten male volunteers received 2-litre infusions of 0.9% (w/v) saline or 5% (w/v) dextrose over 1 h; infusions were carried out on separate occasions, in random order. Weight, haemoglobin, serum albumin, serum and urinary biochemistry and bioelectrical impedance were measured pre-infusion and hourly for 6 h. The serum albumin concentration fell in all subjects (20% after saline; 16% after dextrose) by more than could be explained by dilution alone. This fall lasted more than 6 h after saline infusion, but values had returned to baseline 1 h after the end of the dextrose infusion. Changes in haematocrit and haemoglobin were less pronounced (7.5% after saline; 6.5% after dextrose). Whereas all the water from dextrose was excreted by 2 h after completion of the infusion, only one-third of the sodium and water from the saline had been excreted by 6 h, explaining its persistent diluting effect. Impedances rose after dextrose and fell after saline (P<0.001). Subjects voided more urine (means 1663 and 563 ml respectively) of lower osmolality (means 129 and 630 mOsm/kg respectively) and sodium content (means 26 and 95 mmol respectively) after dextrose than after saline (P<0.001). While an excess water load is excreted rapidly, an excess sodium load is excreted very slowly, even in normal subjects, and causes persistent dilution of haematocrit and serum albumin. The greater than expected change in serum albumin concentration when compared with that of haemoglobin suggests that, while dilution is responsible for the latter, redistribution also has a role in the former. Changes in bioelectrical impedance may reflect the electrolyte content rather than the volume of the infusate, and may be unreliable for clinical purposes.

Impaired specific cell-mediated immunity in experimental biliary obstruction and its reversibility by internal biliary drainage.

Little is known of the effect of cholestasis on host immunity. This study evaluates lymphocytic responsiveness to PHA and LPS mitogen and to allogeneic F344 antigen in Sprague-Dawley rats 21 days following bile duct ligation and 31 days following relief of jaundice by internal biliary drainage. Serum bilirubin level was significantly elevated in the bile duct ligated animals at Day 21 (P less than 0.001) and thereafter returned to preoperative levels following internal biliary drainage. Results demonstrate depressed responsiveness to PHA (P less than 0.001) and allogeneic F344 antigen in vivo (P less than 0.04) and in vitro (P less than 0.02) in bile duct ligated animals as compared to sham, sham pair-fed, and normal control rats. The observed deficiency in responsiveness to T-cell-dependent mitogen and antigen cannot be explained on the basis of complicating nutritional, renal, or infective factors. Subsequent internal biliary drainage results in some improvement in T-cell responsiveness in the bile duct ligated group although recovery is not complete. B-Lymphocytic response to LPS mitogen is not affected by bile duct ligation. We conclude that cholestasis subsequent to extrahepatic biliary obstruction per se results in impairment of cell-mediated immunity in vivo. This impairment is partly reversible by internal biliary drainage. In vitro B-cell function does not appear to be affected in this model. Further study of impaired cell-mediated immunity in extrahepatic biliary obstruction will improve our understanding of the immunological status of patients with obstructive jaundice and cholestatic liver diseases.

Role of the gut in the pathophysiology of extrahepatic biliary obstruction.

BACKGROUND: Gram negative septic events are the commonest source of morbidity and mortality as a result of surgery in jaundiced patients. The large intestine provides the major source of Gram negative bacteria in mammals and is implicated in the pathogenesis of systemic endotoxaemia in obstructive jaundice. Bile salts have an important part in maintaining indigenous microecological homeostasis through their emulsifying properties. AIMS: The aim was to investigate the effects of biliary obstruction and isolated external biliary diversion on gastro-intestinal structure and caecal bacterial flora in relation to bacterial translocation. METHOD: Six groups of adult male Wistar rats were studied (no operation, sham operated, and bile duct ligated (BDL) for one and three weeks and a choledocho-vesical fistula (CDVF) for one week). At the end of the study period plasma was assayed for evidence of endotoxaemia and the animals were tested for bacterial translocation to the mesenteric lymph node complex (MLNC), liver, lungs, and spleen. Quantitative and qualitative bacteriological studies were performed on the caecal contents and segments of colon and terminal ileum were washed and prepared for histological assessment. RESULTS: Bacterial translocation was significantly increased in the BDL1 (68.8%) and BDL3 (60%) groups compared with the sham1 (6.3%), sham3 (9.1%), No operation (0%), and CDVF1 (16.7%) groups. Although translocation was more pronounced in the BDL1 group, this was almost exclusively to the MLNC compared with the more widespread translocation to other organs in the BDL3 group. The BDL3 group was the only group with significantly raised concentrations of endotoxin and anticore glycolipid. The caecal Gram negative aerobic counts were significantly increased in the BDL1 and CDVF1 groups compared with all other groups. There was evidence of structural abnormalities in the terminal ileum of rats jaundiced for three weeks, but not in the other groups. CONCLUSIONS: Biliary obstruction for one and three weeks promotes bacterial translocation although the mechanisms may be different. Absence of intralumenal bile results in a significant but self limiting increase in the Gram negative aerobic population, which may account for translocation in the early stages of biliary obstruction. As the duration of biliary obstruction increases systemic endotoxaemia is a consistent feature which, combined with factors such as immunological depression and physical disruption of gut barrier function, may promote bacterial translocation perpetuating systemic sepsis.

BLUNT CARDIAC RUPTURE

Blunt injury to the heart ranges from contusion to disruption. This report comprises 14 patients seen during a 6-year period with cardiac rupture secondary to blunt trauma. Eight patients were injured in automobile accidents, two patients were injured in auto-pedestrian accidents, two were kicked in the chest by ungulates, and two sustained falls. Cardiac tamponade was suspected in ten patients. Five patients presented with prehospital cardiac arrest or arrested shortly after arrival. All underwent emergency department thoracotomy without survival. Two patients expired in the operating room during attempted cardiac repair; both had significant extracardiac injury. Seven patients survived, three had right atrial injuries, three had right ventricular injuries, and one had a left atrial injury. Cardiopulmonary bypass was not required for repair of the surviving patients. There were no significant complications from the cardiac repair. The history of significant force dispersed over a relatively small area of the precordium as in a kicking injury from an animal or steering wheel impact should alert the physician to possible cardiac rupture. Cardiac rupture should be considered in patients who present with signs of cardiac tamponade or persistent thoracic bleeding after blunt trauma.

Hand grip strength--a simple prognostic indicator in surgical patients.

This study evaluates hand grip strength as an indicator of nutritional status and a predictor of postoperative complications. Hand grip strength and other parameters of nutritional status, namely, midarm muscle circumference, forearm muscle circumference, triceps skinfold, percentage ideal body weight, serum albumin, and percent usual weight were determined preoperatively in 205 patients. Complications occurred in 28 patients (14%). Patients with at least one abnormal nutritional parameter had a higher incidence of postoperative complications. Their length of total and postoperative hospitalization was greater by 6.2 and 4.6 days, respectively (p less than 0.01). Grip strength was the most sensitive single parameter, but forearm muscle circumference and percentage ideal body weight were the most specific indices. Hand grip strength is a simple measure of nutritional status and an accurate prognostic indicator that requires further clinical evaluation.

Conclusive evidence of endotoxaemia in biliary obstruction

Background—Endotoxaemia is implicated in the pathophysiology of obstructive jaundice. The EndoCab enzyme linked immunosorbent assay (ELISA) is a novel assay which measures endogenous antibody (IgG) to the inner core region of circulating endotoxins (ACGA). Aims—To investigate the significance of endotoxaemia in biliary obstruction using the EndoCab assay and assess the specificity of the humoral response to endotoxin compared with an exogenous antigenic challenge (tetanus toxoid, TT). Methods—Three groups of adult male Wistar rats were studied: no operation, sham operation, and bile duct ligation for 21 days (BDL). In the second study, rats rats received prior immunisation with TT. Results—In the preliminary experiment, plasma ACGA was significantly increased in the BDL group (306.6 (18.3)% versus 119.9 (6.7)% and 105.2 (4.6)% in the sham and no operation groups, respectively; p<0.001). Although the mean endotoxin concentration in the BDL group was greater than that in the control groups this was not significant. There was a strong positive correlation between ACGA and endotoxin concentrations (p=0.0021). In the second study mean ACGA after 21 days of BDL was significantly elevated (267.1 (31.2)% versus 101.6 (21.2)% at baseline, p<0.0001). ACGA was unaffected in the other two groups. TT antibody concentrations fell in all three groups; only in the BDL group was the fall significant (97.6 (5.3)% versus 78.8 (4.2)% at baseline, p<0.05). Conclusions—The specific rise in ACGA supports the hypothesis that endotoxin has an integral role in the pathophysiology of obstructive jaundice. The production of anticore glycolipid antibodies specifically reflects systemic endotoxaemia in this model. The EndoCab assay provides a novel, sensitive, and specific method for endotoxin detection.

Urgent thoracotomy for pulmonary or tracheobronchial injury.

Three hundred eighty-eight of 7,283 (5.3%) admitted trauma patients underwent urgent thoracotomy. In 61 patients (15.7%), pulmonary or tracheobronchial injury prompted thoracotomy (11, blunt; 50, penetrating). Pulmonary hemorrhage necessitated thoracotomy in 54 patients (88.5%); tracheobronchial injury in five patients (8.2%). The mortality was 27.9%. Nine patients (14.8%) underwent pneumonectomy: eight died of intractable hemorrhagic shock during thoracotomy despite rapid control of pulmonary hemorrhage: one died of sepsis. Eleven patients (18.0%) underwent lobectomy: six (54.5%) died of concomitant injuries. Thirty-six patients (59.0%) underwent pneumonorrhaphy: one died of concomitant injuries. Five (8.2%) patients underwent tracheobronchial repair: one died of concomitant injuries. Pneumonectomy was uniformly fatal and should be a procedure of last resort in the treatment of pulmonary injury, as lobectomy and pneumonorraphy are better tolerated by these critically ill patients.

Biliary decompression promotes Kupffer cell recovery in obstructive jaundice.

BACKGROUND: Jaundiced patients undergoing surgical procedures have an increased risk of Gram negative sepsis with potential morbidity and mortality. Depressed Kupffer cell clearance capacity (KCCC) predisposes jaundiced patients to endotoxaemia and its sequelae. Biliary decompression remains the main therapeutic strategy in obstructive jaundice. AIMS: This study investigates the efficacy of internal (ID) and external biliary drainage (ED) on KCCC in an experimental model of extrahepatic biliary obstruction. METHODS: Adult male Wistar rats (250-300 g) were assigned to one of six groups: sham operated, where the bile duct was mobilised but not divided; bile duct ligation (BDL) for three weeks, and sham operated or BDL for three weeks followed by a second laparotomy and further 21 days of ID or ED, by way of choledochoduodenostomy or choledochovesical fistula respectively. KCCC was measured using an isolated hepatic perfusion technique with FITC labelled latex particles (0.75 mu) as the test probe. Plasma was assayed for bilirubin, endotoxin, and anticore glycolipid antibody (ACGA) concentrations. RESULTS: Jaundiced rats had reduced KCCC (p < 0.001), increased concentrations of ACGA (p < 0.001), and endotoxin (p < 0.001) compared with controls. Biliary drainage for three weeks produced a recovery in KCCC and normalisation of endotoxin and ACGA concentrations, however, external drainage was less effective than ID (p < 0.01). CONCLUSIONS: These data support the hypothesis that endotoxaemia and its mediated effects are integral in the pathophysiology of jaundice. Furthermore, a short period of internal biliary drainage is a useful therapeutic strategy in restoring Kupffer cell function and negating systemic endotoxaemia and consequent complications in biliary obstruction.