Inflammatory response during abdominal and thyroid surgery: a prospective clinical trial on mediator release.

Several studies have been demonstrated that endotoxin is a potent stimulus of the acute inflammatory response following traumatic injury. Although numerous studies have indicated that the extent of surgical intervention correlates well with the inflammatory response, the potential role of endotoxin as a trigger under those conditions still remains unknown. Therefore, the aim of this study was to elucidate whether or not the up-regulated inflammatory mediators are paralleled by increased endotoxin plasma levels during and following surgery, and whether the extent of surgical intervention represents a crucial factor under those conditions. To study this, plasma was collected at various time points during and after surgery from 52 patients subjected to abdominal surgery (i.e., major surgery) and 25 patients subjected to thyroid surgery (i.e., minor surgery). Plasma was assessed for endotoxin, endotoxin neutralizing capacity (ENC), and inflammatory mediators (leucotriene-C4 [LTC4]-, 6-keto-prostaglandin-F-1-alpha [PGF]-, thromboxane-B2 [TxB2], interleukin-6 [IL-6], and C-reactive protein [CRP]). Furthermore, splanchnic blood circulation was measured by determination of the intraluminal pH of the stomach and sigma (pHi) by intraluminal tonometry. Mesenteric lymph nodes were also collected at the time point of organ mobilization in the major surgery group and were assessed for bacterial translocation. Among all parameters investigated, endotoxin showed the most rapid changes. A significant increase in plasma levels of endotoxin and a decrease of ENC were found in the major surgery groups following induction of anesthesia and in the minor surgery groups after skin incision. Moreover, the incidence of elevated endotoxin levels was significantly higher (89% with elevated endotoxin levels) than the incidence of bacterial translocation (35% with gram-negative bacteria) in mesenterial lymph nodes of the major surgery group. pHi decreased significantly in both groups after skin incision, but no difference was observed between the major and minor surgery groups. Plasma mediators of the arachidonic acid cascade (LTC4, PGF, and TxB2) were only elevated in individual patients during and following surgery in both groups. Conversely, the post-operative increase in the acute phase mediators was significantly different in the major and minor surgery groups. IL-6 plasma levels peaked higher and earlier after major surgery than after minor surgery and the delayed increase of CRP was significantly greater in the major surgery group. In conclusion, the results indicate that plasma levels of endotoxin significantly correlate with the severity of the surgical intervention and may play an important role in inducing mediators of the acute phase reaction under such conditions.

Hepato-splanchnic metabolic effects of the stable prostacyclin analogue iloprost in patients with septic shock.

OBJECTIVE: To evaluate the effects of the stable prostacyclin analogue iloprost on hepato-splanchnic blood flow, oxygen exchange and metabolism in patients with septic shock. DESIGN: Prospective clinical study. SETTING: Intensive care unit in a university clinic. PATIENTS: Eleven patients with septic shock requiring norepinephrine to maintain mean arterial pressure above 70 mmHg. INTERVENTIONS: Iloprost was incrementally infused to increase cardiac index by 15%. MEASUREMENTS AND MAIN RESULTS: Splanchnic blood flow (Qspl) was measured using the steady-state indocyanine-green infusion technique and endogenous glucose production rate (EGP) using a stable isotope approach. Systemic and splanchnic oxygen consumption (VO2), the hepato-splanchnic uptake rates of the glucose precursors lactate, pyruvate, alanine and glutamine, the hepatic venous redox state and gastric mucosal-arterial PCO2 gradients were determined. After a baseline measurement, iloprost infusion was started. After 90 min all measurements were repeated and a third measurement was obtained after another 90 min following iloprost withdrawal. Qspl (baseline I: 0.82/0.75-1.08 l x min x m2; iloprost: 0.94/0.88-1.29 l x min x m2; baseline II: 0.87/0.74-1.09 l x min x m2) and splanchnic oxygen delivery (baseline I: 122/103-166 ml x min x m2; iloprost: 134/117-203 ml x min x m2; baseline II: 130/98-158 ml x min x m2) significantly increased. While systemic VO2 significantly increased (baseline I: 139/131-142 ml x min x m2; iloprost: 147/136-164 ml x min x m2; baseline II: 143/133-154 ml x min x m2) splanchnic VO2 increased in 9 of 11 patients which, however, did not reach statistical significance. EGP significantly decreased (baseline I: 23/16-26 micromol x kg x min; iloprost: 16/14-21 micromol x kg x min; baseline II: 18/12-20 micromol x kg x min), whereas all other parameters of energy metabolism remained unchanged. CONCLUSION: In patients with septic shock an iloprost-induced increase in cardiac index increased splanchnic blood flow and shifted oxygen utilization from the energy requiring de novo glucose production rate to other oxygen-demanding metabolic pathways.

Influence of prone position on gastric mucosal-arterial PCO2 gradients.

OBJECTIVE: To evaluate the effects of mechanical ventilation in the prone position on gastric mucosal-arterial PCO2 gradients. DESIGN: Prospective clinical study. SETTING: Intensive care unit in a university clinic. PATIENTS: Twenty-five patients requiring mechanical ventilation. The physician in charge indicated the turning manoeuver for the individual patient. MEASUREMENTS/RESULTS: In addition to routine measurements of global hemodynamics and gas exchange we determined: 1) intragastric pressure; and 2) gastric mucosal-arterial PCO2 difference. After a baseline measurement in the supine position patients were turned to the prone position. After 60', 120', a median of 6.5 h (2-10 h) in the prone position, and again after 60' in the supine position, all measurements were repeated. Global hemodynamics remained unaltered throughout the study. While gastric mucosal-arterial PCO2 gradients did not change significantly during the first 60 min in the prone position, they significantly increased during the following 60 min [median/percentile: baseline: 6 (1 to -3); 60': 7 (15-5); 120': 13 (20-8) mmHg]. The median intragastric pressure was not significantly affected [baseline: 10 (13-5); 60': 12 (16-8); 120': 11 (13-7) mmHg], but 9 of the 11 patients in whom intragastric pressure increased during the first 60 min in the prone position also showed significantly increased PCO2 gradients (P < 0.01). CONCLUSION: Mechanical ventilation in the prone position may be affiliated with increased tonometric gastric mucosal-arterial PCO2 gradients depending on the effect on intraabdominal pressure. Measuring intraabdominal pressure and/or gastric mucosal PCO2 via a nasogastric tube therefore may help to detect adverse effects of this ventilatory strategy.

Value of Candida antigen and antibody assays for the diagnosis of invasive candidosis in surgical intensive care patients.

During a 3-year period, a clinical diagnosis of invasive candidosis was made in 8 out of 2054 consecutive surgical intensive care unit (ICU) patients. These patients were retrospectively matched with 16 control patients who underwent similar surgical procedures and had a similar clinical course except for negative Candida cultures. In all patients, Candida antigen (Ramco CandTec serum antigen test) and antibody serology (Candida HA test) were determined at least once a week during their stay. The antigen test was positive in 1/8 patients and 4/16 controls and thus did not differentiate patients with candidosis from non-infected controls. The HA antibody titer results fulfilled the manufacturer's criteria for positivity in 7/8 patients with candidosis and 2/16 control patients. Thus, the Candida HA antibody test, but not the Ramco antigen test, can be recommended to confirm a clinical diagnosis of invasive candidosis.

Effect of dopexamine on hepatic metabolic activity in patients with septic shock.

Hepato-splanchnic metabolic activity is seen to be related to regional blood flow and oxygen/substrate availability in patients with sepsis. Catecholamines, which may modulate metabolic activity perse, are common to stabilize hemodynamics. We studied the effect of a dopexamine-induced increase in splanchnic blood flow (Qspl) on regional metabolic rate in 10 patients with septic shock requiring norepinephrine to maintain mean arterial pressure (>60 mmHg). Splanchnic blood flow was determined using the indocyanine-green method with hepatic venous sampling. We determined the hepato-splanchnic lactate, pyruvate, alanine, and glutamine turnover and the lactate/pyruvate and ketone body ratio as well as the endogenous glucose production (EGP) using the stable isotope approach. Qspl increased from 0.86 (0.79-1.15) to 0.96 (0.92-1.33) L/min/m2, not influencing any parameter of metabolic activity. We speculate that this finding is due to altered beta-adrenoreceptor-mediated thermogenic effects due to the interplay of different beta-sympathomimetics at the receptor site.

Does gastric juice pH influence tonometric PCO2 measured by automated air tonometry?

To determine the influence of changes in gastric juice pH due to intravenous administration of pentagastrin and omeprazole on intramucosal regional PCO2 (Pr(CO2)), we investigated 17 healthy human volunteers. Gastric juice pH was obtained from a glass pH electrode for continuous gastric juice pH measurement and Pr(CO2))was measured by using automated air tonometry. After baseline (8:00 A.M.-9:00 A.M.) the subjects received 0.6 microg/kg/h pentagastrin intravenously for 1 h (9:00 A.M.-10:00 A.M., after stimulation 10:00 A.M.-11:00 A.M.) and 40 mg omeprazole intravenously (after omeprazole 11:00 A.M.-3:00 P.M.). Following pentagastrin administration gastric juice pH significantly decreased from 1.2 +/- 0.4 to 0.6 +/- 0.4 (mean +/- SD, p < 0.007, versus baseline), whereas omeprazole transiently increased luminal pH up to 4.4 +/- 1.7 (p < 0.007 versus baseline). These subsequent changes in gastric juice pH were accompanied by a significant increase in Pr(CO2) from 48 +/- 12 to 61 +/- 17 mm Hg (p < 0.007 versus baseline) and a decrease to 44 +/- 5 mm Hg (p < 0.002 versus pentagastrin), respectively. A gastric juice pH > 4 considerably reduces mean gastric Pr(CO2) and interindividual variability. Thus omeprazole may improve the validity of gastric tonometry data.

[Enteral nutrition in acute pancreatitis]. / Enterale Ernährung bei akuter Pankreatitis.

The metabolism of acute pancreatitis is characterized by hypermetabolism and catabolism. Evidence for glucose intolerance occurs in anywhere from 40 to 90% of cases and urine urea nitrogen may increase up to 40 g/day. The most important aspect when considering nutritional therapy is determining the severity of the pancreatitis. The APACHE-II-scoring-system and the time honored Ranson criteria are useful for differentiating severe from mild pancreatitis. Despite some limitations in sensitivity and specificity, studies have suggested that patients with 2 or less Ranson criteria and an APACHE-II-score of 9 or less have mild pancreatitis, while patients with 3 or more Ranson criteria and an APACHE-II-score of 10 or more have severe pancreatitis. Evidence of organ failure on clinical presentation and pancreatic necrosis on dynamic CT scan are also important factors in determining severity of pancreatitis and are probably the two major indicators of patient outcome. Only 3 prospective randomized controlled trials have compared enteral to parenteral nutrition for pancreatitis. All studies described successful use of enteral feeding without exacerbating the disease process although a mild stimulation of exocrine pancreatic secretion could not be prevented, even when the tube was placed below the ligament of Treitz. Kalfarentzos [11] and McClave [14] could show that hyperglycemia was worse in the parenteral feeding patients compared to the enteral feeding group and Windsor [24] concluded with respect to the results of his study, that enteral feeding modulates the inflammatory response in acute pancreatitis. Conclusions regarding the use of enteral or parenteral nutrition in acute pancreatitis are difficult to form, as there is a need of more prospective studies. As ileus may be a problem in patients with greater severity of pancreatitis, limiting the application of early enteral feeding, the route of nutritional support should be determined by the clinical course and the severity of the disease.

Tap water colonization with Pseudomonas aeruginosa in a surgical intensive care unit (ICU) and relation to Pseudomonas infections of ICU patients.

Water faucets on a surgical intensive care ward were examined prospectively as a source of Pseudomonas aeruginosa infections. All water outlets harbored distinct genotypes of P aeruginosa over prolonged time periods. Over a period of 7 months, 5 (29%) of 17 patients were infected with P aeruginosa genotypes also detectable in tap water.

CD64 surface expression on neutrophils is transiently upregulated in patients with septic shock.

OBJECTIVE: To clarify the changes in total leukocyte counts, CD64 neutrophil receptor expression and serum granulocyte colony-stimulating factor (G-CSF) concentrations in critically ill patients without infection and sepsis and in patients with septic shock. DESIGN: Prospective study. SETTING: Intensive care unit (ICU) and research laboratory of a university hospital. PATIENTS: Eleven critically ill patients without infections and 22 patients with proven infections in septic shock for the first time and of at least 3 days' duration. MEASUREMENTS AND RESULTS: Over a 6month period, a longitudinal analysis of expression of the monomeric Fc receptor type I (CD64, FcgammaRI) on neutrophils was performed by flow cytometric analysis on a daily basis in all postoperative/post-traumatic patients admitted to the ICU until discharge from the ICU or death. Out of 273 patients, 11 patients without sepsis had organ failure and 22 patients with proven infections had septic shock for the first time and of at least 3 days' duration. Ten out of the 22 patients survived, 12 died. CD64 expression was greater in patients with septic shock than in patients without sepsis. Moreover, CD64 expression was only initially and transiently elevated in most survivors (9/10) and non-survivors (8/12) of septic shock. In survivors, G-CSF serum concentrations were markedly decreased in the 2nd week. CONCLUSIONS: Decreased neutrophil CD64 expression in an acutely ill population with septic shock may reflect the development of a non-responsive state as well as the early downregulation of neutrophil activation prior to the resolution of an ongoing infection.

Effect of a dopexamine-induced increase in cardiac index on splanchnic hemodynamics in septic shock.

In 12 patients with hyperdynamic septic shock we studied the effect of dopexamine, a combined dopamine and beta-adrenergic agonist, on hepatosplanchnic hemodynamics and O(2) exchange. All patients required noradrenaline to maintain mean arterial pressure > 60 mm Hg (noradrenaline >/= 0.04 microg x kg(-1) x min(-1)) with a cardiac index >/= 3.0 L/min/m(2). Splanchnic blood flow (Qspl) was measured using primed continuous infusion of indocyanine green dye with hepatic venous sampling. In addition tonometric gastric mucosal-arterial and gastric mucosal-hepatic venous P CO(2) gradients were assessed as indicators of regional energy balance. After 90 min of stable hemodynamics a first measurement was obtained. Then dopexamine infusion was titrated (1-4 microg x kg(-1) x min(-1)) to increase cardiac output by approximately 25% (20-30%). After 90 min all measurements were repeated, and dopexamine was withdrawn followed by a third measurement. Median Qspl (0.86/1.23-0. 66 versus 0.96/1.42-0.85 L/min/m (2) [median value/25th-75th percentiles], p < 0.05) increased whereas the fractional contribution of Qspl to total blood flow decreased (21/28-13 versus 19/28-12%, p < 0.05). Although both global and regional oxygen delivery (DO(2)) consistently increased, neither global or regional V O(2) nor PCO(2) gradients were significantly affected. In patients with septic shock and ongoing noradrenaline treatment dopexamine seems to have no preferential effects on hepatosplanchnic hemodynamics, O(2) exchange, or energy balance.

[Invasive Candida infection in surgical patients: a valid clinical entity]. / Die invasive Candidainfektion chirurgischer Patienten: Eine valide klinische Entität.

OBJECTIVE: Establishment of a case definition for invasive candidosis in postsurgical intensive care patients. METHODS: During the period of 1996-1999, 8 cases of invasive candidosis were observed on a surgical intensive care unit. Patient records were evaluated with respect to diagnostic criteria and response to antimycotic therapy. RESULTS: Patients included 3 women and 5 men with a mean age of 62.7 (37-85) years. Candida peritonitis (n = 6) occurred after surgery or perforation of the intestinal tract, and Candida pneumonia was due to artificial ventilation (n = 3). C. albicans was isolated in all 8 cases, but mixed infections with other Candida spp. occurred in 3 cases. The Candida serum antigen test yielded a positive result in only 2/8 cases. I.v. therapy with fluconazole was successful in 7 cases, one patient with severe initial disease died with ongoing infection. With the exception of the lethal case, all patients showed a diagnostic serum antibody test, proving systemic candida infection. CONCLUSION: Based on the case descriptions, we propose the following definition of invasive candidosis: (1) Clinical signs of infection after surgery, (2) absence of bacterial pathogens and/or failure to respond to systemic antibiotics, (3) cultivation of Candida spp. from normally sterile sites or abundant growth in tracheal aspirate, (4) response to antimycotic therapy and (5) diagnostic serum antibody test. This definition proved to be valid for our patients and could be used as an inclusion criterion for future clinical studies of serodiagnosis of Candida infection or antimycotic chemotherapy.

[Cost analysis concerning MRSA-infection in ICU]. / Eine Kostenanalyse von MRSA-Infektionen auf einer operativen Intensivstation.

OBJECTIVE: MRSA-infection incidences are still rising, because of unreflected use of antibiotic drugs in man and animals. Although some European countries already have an incidence as high as 30% of MRSA infection in ICU-patients, there is no additional financial support for the treatment of MRSA infected patients. METHODS: We investigated all MRSA infected patients of the operative ICU ward of the department of anaesthesia at the university Ulm within the last three years. We calculated all costs for decontamination and special treatment of the MRSA infection as well as the costs for closing beds, because of MRSA precaution and isolation reasons. RESULTS: The average monthly costs for MRSA infected patients is about 3848 EURO for decontamination and treatment, and another 5560 EURO fix costs. The average monthly ICU duration for MRSA patients was 5.8 days, which means a financial loss of 1622 EURO per "MRSA-patient day". This loss is more than two times the price the social security system pays for an ICU-patient. CONCLUSION: These extra costs should be calculated and additionally paid for patients with MRSA-infection in order to obtain a certain quality standard. By achieving this standard the total economy costs for MRSA infection treatment could be reduced.

Changes in gastric intramucosal pH following mesenteric traction in patients undergoing pancreas surgery.

BACKGROUND/AIM: During major abdominal surgery, mesenteric traction (MT) may result in hemodynamic instability mainly due to endogenous prostacyclin release. Gastric intramucosal pH (pHi) and PiCO2 are indicators of splanchnic tissue perfusion with a predictive value for the postoperative outcome. We investigated the influence of MT on gastric pHi and on postoperative outcome in patients undergoing pancreas surgery. METHODS: Forty-six consecutive patients scheduled for pancreas surgery were investigated. We registered hemodynamics and pHi by gastric tonometry and documented postoperative outcome (complications, hospital stay). Baseline data (T0) were recorded after skin incision. Further assessments followed 30, 60 and 120 min after intentional MT (T1-3) and at the end of surgery (T4). RESULTS: Thirty-three patients demonstrated a decrease in mean arterial pressure (MAP) following MT, whereas 13 patients showed entirely stable hemodynamics. The significant reduction in MAP in patients with an MT response was not associated with changes in pHi as compared to patients with no response (stable MAP) (T0 7.34 +/- 0.08 vs. 7.35 +/- 0.06; T1 7.34 +/- 0.05 vs. 7.32 +/- 0.07; T2 7.32 +/- 0. 05 vs. 7.31 +/- 0.08; T3 7.32 +/- 0.05 vs. 7.32 +/- 0.07; T4 7.26 +/- 0.1 vs. 7.27 +/- 0.08; mean +/- SD, MT response vs. no response). Neither MT response nor gastric intramucosal acidosis as evidenced by a pHi <7.32 at the end of surgery predicted postoperative complications or longer hospital stay. CONCLUSION: No deterioration of gastric pHi was found, which could reflect acceptable splanchnic perfusion and oxygenation despite systemic blood pressure reactions in patients experiencing an MT response.

Endotoxin binding and elimination by monocytes: secretion of soluble CD14 represents an inducible mechanism counteracting reduced expression of membrane CD14 in patients with sepsis and in a patient with paroxysmal nocturnal hemoglobinuria.

Little is known about the role of peripheral blood mononuclear cells (PBMCs) in lipopolysaccharide (LPS) elimination. We studied the endotoxin elimination capacities (EEC) of PBMCs of 15 healthy volunteers, 13 patients with sepsis, and 1 patient suffering from paroxysmal nocturnal hemoglobinuria (PNH). Although expression of CD14, the best-characterized receptor for LPS to date, was reduced from 93.6% +/- 0.8% in healthy subjects to 50.5% +/- 6.5% in patients with sepsis and was 0.3% in a patient with septic PNH, EEC were found to be unchanged. There was no difference in the amount of tumor necrosis factor alpha (TNF-alpha) released by PBMCs of healthy donors and patients with sepsis. Anti-CD14 antibodies (MEM-18) completely suppressed EEC, binding of fluorescein isothiocyanate-labeled LPS to monocytes as determined by FACScan analysis, and TNF-alpha release in all three groups studied. The concentrations of soluble CD14 (sCD14) secreted by endotoxin-stimulated PBMCs from healthy donors and patients with sepsis amounted to 4.5 +/- 0.4 and 20.1 +/- 1.8 ng/ml, respectively. Based on our results, we suggest that PBMCs eliminate LPS by at least two different mechanisms; in healthy subjects, the membrane CD14 (mCD14) receptor is the most important factor for LPS elimination, while in patients with sepsis (including the septic state of PNH), increased sCD14 participates in LPS elimination. Secretion of sCD14 is strongly enhanced under conditions of low expression of mCD14 in order to counteract the reduction of mCD14 and maintain the function of monocytes. This sCD14 may substitute the role of mCD14 in LPS elimination during sepsis. The elimination of LPS by PBMCs correlates with the binding reaction and the secretion of TNF-alpha.

[Postoperative and post-traumatic acute cholecystitis. Value of ultrasound diagnosis]. / Die postoperative und posttraumatische akute Cholecystitis. Stellenwert der sonographischen Diagnostik.

An often unrecognized but potentially fatal complication, mostly seen in posttraumatic patients under intensive care, is reactive acute cholecystitis. On account of the high specificity of ultrasound diagnosis in the biliary system we decided to examine the ultrasound criteria for early detection of posttraumatic cholecystitis. Ultrasound of the abdomen was performed prospectively, seven times on different days, in each of 40 artificially respirated patients under intensive care conditions over a period of 12 months. The results show that artificial respiration, parenteral feeding and previous trauma can lead to tardive (28/40) wall-thickening or to a three-layered wall of the gallbladder (9/40). In 22.5% of patients (9/40) we found the sonographic signs of acute cholecystitis. In correlation with the clinical signs, cholecystectomy was indicated in only two patients. The preoperative ultrasonographic findings and clinical signs of 23 patients with the diagnosis of acute reactive cholecystitis were analysed retrospectively. We found good correlation between sonographic and clinical signs of acute cholecystitis in 21 of these 23 patients. Our study shows that the morphological correlate of a thickened three-layered gallbladder wall can occur in the context of systemic alterations, even if there is no underlying cholecystitis. The diagnosis of acute reactive cholecystitis and the indication for cholecystectomy should be based on the synopsis of pathologic and clinical findings.

Effects of a dobutamine-induced increase in splanchnic blood flow on hepatic metabolic activity in patients with septic shock.

BACKGROUND: Septic shock leads to increased splanchnic blood flow (Qspl) and oxygen consumption (VO2spl). The increased Qspl, however may not match the splanchnic oxygen demand, resulting in hepatic dysfunction. This concept of ongoing tissue hypoxia that can be relieved by increasing splanchnic oxygen delivery (DO2spl), however, was challenged because most of the elevated VO2spl was attributed to increased hepatic glucose production (HGP) resulting from increased substrate delivery. Therefore the authors tested the hypothesis that a dobutamine-induced increase in Qspl and DO2spl leads to increased VO2spl associated with accelerated HGP in patients with septic shock. METHODS: Twelve patients with hyperdynamic septic shock in whom blood pressure had been stabilized (mean arterial pressure > or = 70 mmHg) with volume resuscitation and norepinephrine received dobutamine to obtain a 20% increase in cardiac index (CI). Qspl, DO2spl, and VO2spl were assessed using the steady-state indocyanine green clearance technique with correction for hepatic dye extraction, and HGP was determined from the plasma appearance rate of stable, non-radio-active-labeled glucose using a primed-constant infusion approach. RESULTS: Although the increase in CI resulted in a similar increase in Qspl (from 0.91 +/- 0.21 to 1.21 +/- 0.34l.min-1.m2; P < 0.001) producing a parallel increase of DO2spl (from 141 +/- 33 to 182 +/- 44 ml.min-1.m2; P < 0.001), there was no effect on VO2spl (73 +/- 16 and 82 +/- 21 ml.min-1.m2, respectively). Hepatic glucose production decreased from 5.1 +/- 1.6 to 3.6 +/- 0.9 mg.kg-1.min-1 (P < 0.001). CONCLUSIONS: In the patients with septic shock in whom blood pressure had been stabilized with volume resuscitation and norepinephrine, no delivery-dependency of VO2spl could be detected. Oxygen consumption was not related to the accelerated HGP either, and thus the concept that HGP dominates VO2spl must be questioned in well-resuscitated patients with septic shock.

Epidemiology of acute renal failure and outcome of haemodiafiltration in intensive care.

OBJECTIVE: To examine the epidemiology of acute renal failure (ARF) and to identify predictors of mortality in patients treated by continuous venovenous haemodiafiltration (CVVHDF). DESIGN: Uncontrolled observational study. SETTING: One intensive care unit (ICU) at a surgical and trauma centre. PATIENTS: A consecutive sample of 3591 ICU treatments. MEASUREMENTS AND RESULTS: Demographic data, indications for ICU admission, severity scores and organ system failure at the beginning of CVVHDF were set against the occurrence of ARF and ICU mortality. 154 (4.3% of ICU patients and 0.6% of the hospital population) developed ARF and were treated with CVVHDF. Higher American Society of Anaesthesiologists (ASA) status and higher Apache II score were associated with ICU incidence of ARF. However, these criteria were not able to predict outcome in ARF. A simplified predictive model was derived using multivariate logistic regression modelling. The mortality rates were 12% with one failing organ system (OSF), 38% with two OSF, 72% with three OSF, 90% with four OSF and 100% with five OSF. The adjusted odds ratio (OR) of death was 7.7 for cardiovascular failure, 6.3 for hepatic failure, 3.6 for respiratory failure, 3.0 for neurologic failure, 5.3 for massive transfusion and 3.7 for age of 60 years or more. CONCLUSION: General measures of severity are not useful in predicting the outcome of ARF. Only the nature and number of dysfunctioning organ systems and massive transfusion at the beginning of CVVHDF and the age of the patients gave a reliable prognosis in this group of patients.

Bacterial colonization and endotoxin contamination of intravenous infusion fluids.

Bacterial colonization and endotoxin contamination of intravenous infusion fluids and catheter systems were examined in a surgical intensive care unit. Nineteen consecutive patients were randomly assigned to 48 h (N = 8) or 96 h (N = 11) change of infusion systems. Fluid from infusion bottles (51), infusion bottles plus burettes (102) and catheter systems (104) was cultured quantitatively for aerobic and anaerobic bacteria. Swabs (362) were taken from three-way stopcocks before and after the in-line infusion filters. Total and free endotoxin levels in infusion fluids were measured by quantitative chromogenic Limulus assay. The overall rate of bacterial colonization of bottles/burettes was 7.8% at 48 h and 15.7% at 96 h, while colonization rates of catheter fluid were 34.0% and 24.1%, respectively (n.s.). These high rates of colonization, despite regularly reinforced hand disinfection practices, may be explained by the high frequency of manipulations of the catheter systems, during acute interventions in emergency situations. Cell-bound endotoxin was found in 8.8% of the samples, but only 2.5% of the samples contained free endotoxin. The data support the use of in-line infusion filters, with bacterial-retaining property; however, these filters need not have endotoxin-retaining properties.

Aerosolized prostacyclin and inhaled nitric oxide in septic shock--different effects on splanchnic oxygenation?

OBJECTIVES: To compare the effects of inhaled nitric oxide and aerosolized prostacyclin (PGI2) on hemodynamics and gas exchange as well as on the indocyanine-green plasma disappearance rate and gastric intramucosal pH in patients with septic shock. DESIGN: Prospective, randomized, interventional clinical study. SETTING: Intensive care unit in a university hospital. PATIENTS: Sixteen patients with pulmonary hypertension and septic shock according to the criteria of the ACCP/SCCM consensus conference all requiring norepinephrine and/or epinephrine to maintain mean arterial blood pressure above 65 mmHg. METHODS AND INTERVENTIONS: Patients were randomly assigned to receive either nitric oxide or aerosolized prostacyclin. Nitric oxide was inhaled using a commercially available delivery system, prostacyclin was administered with a modified ultrasound nebulizer. Both nitric oxide and prostacyclin were incrementally adjusted to obtain a 15% decrease of mean pulmonary artery pressure. Hemodynamics and gas exchange as well as indocyanine-green plasma disappearance rate and gastric intramucosal pH were determined at baseline after 90 min in steady state, after 90 min of nitric oxide inhalation or prostacyclin aerosol administration had elapsed in stable conditions, and after 90 min in stable conditions after nitric oxide or prostacyclin withdrawal. RESULTS: Both inhaled nitric oxide and aerosolized prostacyclin selectively reduced the mean pulmonary artery pressure from 35 +/- 4, 30 +/- 4 mmHg (p < 0.05) and 34 +/- 4 to 30 +/- 3 mmHg (p < 0.05) respectively; after removal of nitric oxide and prostacyclin, the mean pulmonary artery pressure returned to the baseline values. Systemic hemodynamics remained unaltered during the vasodilator treatment. While the mean PaO2 was not significantly influenced, it increased in 4/8 of the NO- and 3/8 of the PGI2-treated patients. Neither of the drugs influenced indocyanine-green plasma disappearance rate, but prostacyclin--unlike nitric oxide--significantly increased gastric intramucosal pH (from 7.26 +/- 0.07 to 7.30 +/- 0.05, p < 0.05) which remained elevated in four of these patients after prostacyclin removal, and decreased the arterial-gastric mucosal pressure of carbon dioxide gap from 19 +/- 6 to 15 +/- 4 mmHg (p < 0.05). CONCLUSIONS: Our data suggest that aerosolized prostacyclin--unlike nitric oxide--has similar beneficial effects on splanchnic perfusion and oxygenation as intravenous prostacyclin without detrimental effects on systemic hemodynamics. The different effects of prostacyclin and nitric oxide might be explained by the longer half-life of prostacyclin associated with a certain spillover into the systemic circulation.