Multiple system organ failure

Potential preventive and therapeutic effect of Chinese herb rhubarb (da huang) for intensive care unit/pediatric intensive care unit gastrointestinal failure patients: A protocol for systematic review

INTRODUCTION

The Chinese herb da huang (DH) (Rhubarb) is commonly used for GIF intensive care unit (ICU)/pediatric intensive care unit (PICU) gastrointestinal failure (GIF) patients in China. However, the potential preventive and therapeutic effect of DH in these patients has not yet been studied systematically.

OBJECTIVES

The aim of this study was to evaluate the preventive and therapeutic effects of DH in treating ICU/PICU GIF patients with the most recent evidence.

METHODS

We systematically searched 7 databases from inception to March 30, 2018. RevMan 5.3 software was used to perform a meta-analysis. GRADE methodology was applied to evaluate the quality of evidence for each outcome. The review protocol was registered on PROSPERO (CRD42018092710) in advance.

RESULTS

Seven studies comprising 788 pediatric or adult participants were included in this analysis. Three indicators, including GIF occurrence rates (gastrointestinal mucosal hemorrhage, enteroplegia), multiple organ dysfunction syndrome (MODS)-related items (occurrence rates of MODS, mortality rates of MODS) and duration in the ICU was analyzed. The GIF occurrence rate meta-analysis result was (RR 0.47, CI 95% 0.37-0.60; P = .95); MODS related items indicator result was (RR 0.44, CI 95% 0.33-0.59; P = .41); ICU duration ICU result was (RR -2.87, CI 95% -3.53--2.21; P = .40). The safety of Chinese herb DH (Rhubarb) remains unclear.

CONCLUSION

Current evidence suggests that the Chinese herb rhubarb (DH) powder combined with Western medicine was inferior to Western medicine alone in terms of preventive and therapeutic effects in ICU/PICU patients in terms of decreasing GIF occurrence rates (gastrointestinal mucosal hemorrhage and enteroplegia), occurrence rates of MODS, mortality from MODS, and shortened duration time in the ICU/PICU. However, larger sample sizes and rigorously-designed studies are necessary to conclusively determine the association between DH powder and outcomes in ICU/PICU GIF patients.

Diagnostic laparoscopy to investigate unexplained lactic acidosis in critically ill patients - A descriptive single centre cohort study

Introduction

Unexplained lactic acidosis (LA) in a critically ill patient often prompts investigations to rule out any reversible intra-abdominal cause. Equivocal results can lead to an emergency laparotomy (EL) with subsequent high morbidity and mortality rates. Our objective was to determine the clinical impact of urgent diagnostic laparoscopy (UDL) in such patients.

Methods

This was a descriptive single-centre cohort study. UDL on 28 consecutive critically ill patients with unexplained LA who were referred to a single surgeon over 16 years period were analysed. UDL was proformed either at bedside or in theatre without prior computerised tomography (CT) scan. Patient's demographics, ASA grade, referral route and intraoperative findings were analysed.

Results

Eighteen patients underwent bedside UDL in the critical care setting and further 10 had UDL in theatre. Fourteen patients had normal UDL, out of these 10 had LA secondary to low cardiac output states. Fourteen patients had positive UDL findings. Seven patients had features of mesenteric ischaemia, two had gangrenous gallbladder, two had hepatic ischaemia, one patient had acute pancreatitis, one had gangrenous uterus and one had gastric volvulus. Five of the 14 patients with positive UDL were converted to laparotomy for definitive management. In total, of the 28 patients in the cohort, 23 patients avoided EL.

Conclusion

UDL is useful and feasible investigation for unexplained LA in the critically ill patients and it can avoid unnecessary EL in many patients. We would recommend the use of UDL as a safe and feasible investigation in such patients.

•

Lactic Acidosis likely from an intra-abdominal source usually prompts explorative Laparotomy.

•

We performed diagnostic laparoscopy for 28 critically ill patients with Lactic Acidosis.

•

These patients underwent diagnostic laparoscopy prior to any CT scanning, in either bedside or theatre setting.

•

50% of patients had a normal Laparoscopy results and Explorative laparotomy was prevented in 18% of patients.

•

Diagnostic Laparoscopy is safe and feasible when investigating lactic acidosis from an intra-abdominal source and risks are reduced with explorative laparotomy.

Multiple System Organ Failure in the Adult Respiratory Distress Syndrome

Recently completed studies suggest that patients with the adult respiratory distress syndrome (ARDS) manifest early evidence of multiple-site endothelial injury. Ex trapulmonary disease is usually the cause of death in these patients. Furthermore, prognosis in individual cases of ARDS is strongly influenced by specific organ failures (e.g., hepatic and renal failure). The mechanisms by which ARDS and extrapulmonary organ system fail ure interact, however, are poorly delineated. We ad dress three aspects of the multisystemic nature of ARDS. First, we analyze evidence that suggests ARDS is a mul tisystem disorder fron the outset, involving panendothe lial injury mediated by cellular interactions and humoral substances that act similarly at many vascular target sites. Second, we discuss the role of three extrapulmo nary organs in the modulation of ARDS: the liver, the gastrointestinal mucosa, and the kidneys. Third, we ad dress the unifying hypothesis that uncontrolled ongoing inflammation, which is often but not always caused by infection, is the essential link between ARDS and its progression to multiple system organ failure.

Delivery systems for antioxidant nutrients

The novel role of oxidants and antioxidants as part of cell signaling cascades has opened new areas of research in several disease states and their therapeutic strategies. For successful therapeutic manipulation of reactive oxygen species (ROS)-mediated cellular signaling pathways, it would necessitate control of the critical balance of oxidants/antioxidants in the target site by the antioxidant. Another way of controlling the critical balance is to avoid excessive generation of ROS from nutrients and/or drugs. From the viewpoint of controlling the balance between the oxidant and antioxidant status, this review focuses on the prodrug approach for delivery systems of vitamin E, a major antioxidant nutrient in the membrane, and on the reductive activation-independent delivery system of vitamin K hydroquinone by a prodrug approach, which can avoid excessive generation of ROS synchronized with the activation process of vitamin K.

Ga-67 scan to detect intra-abdominal infection in patients after colorectal surgery

PURPOSE

Intra-abdominal infection is still an important issue in colorectal surgery. The Ga-67 scan is relatively inexpensive, but the delay in diagnosis and the intense physiologic bowel activity are considerable drawbacks to its use in abdominal investigations. In this study, the authors performed 24-hour Ga-67 scans and read the images with the surgeon to detect abdominal infection in patients who underwent colorectal surgery.

METHODS

Sixty-one patients who underwent colorectal surgery were enrolled in this study. Ga-67 scintigraphy was performed 24 hours, and later as needed, after the injection of 111 MBq (3 mCi) Ga-67 citrate. All scans were interpreted together by a nuclear medicine specialist and the surgeon. The intensity of Ga-67 uptake was recorded as grade 0: no uptake; grade 1: less than liver uptake; grade 2: equal to liver uptake; or grade 3: greater than liver uptake. When the intensity of Ga-67 uptake was equal to or greater than grade 2, the pattern of Ga-67 uptake was classified as changing or unchanging. A positive Ga-67 scan was defined as having an intensity of grade 2 or 3 with an unchanging pattern.

RESULTS

Nineteen abdominal infections were diagnosed, all by Ga-67 scans, for a diagnostic sensitivity rate of 100%. Of the 42 patients with no intra-abdominal infection, only 2 had positive Ga-67 scans. This resulted in a specificity rate of 95.2%. The overall accuracy of the Ga-67 scan in the detection of intra-abdominal infection after colorectal surgery was 96.7%.

CONCLUSIONS

The Ga-67 scan is useful for detecting intra-abdominal infection after colorectal surgery. Reading the images with the surgeon and using a lateral view can decrease the false-positive rate. A negative Ga-67 scan can rule out intra-abdominal infection, whereas a positive Ga-67 scan indicates the need for further patient evaluation after colorectal surgery.

Polyneuropathies in critically ill patients: a prospective evaluation

OBJECTIVE

To determine the incidence, severity and course of polyneuropathies in patients with sepsis or systemic inflammatory response syndrome combined with multiple organ failure.

DESIGN

Prospective study.

SETTING

Division of Intensive Care Medicine of the Department of Anesthesiology and Intensive Care and Intensive Care Unit of the Department of Neurology, University Hospital Innsbruck, Austria.

PATIENTS

Twenty-two patients between 23 and 77 years old with sepsis or systemic inflammatory response syndrome combined with multiple organ failure fulfilling strict inclusion and exclusion criteria.

INTERVENTIONS

Clinical neurologic examination and electro myography/nerve conduction velocity measurements during the stay on the Intensive Care Unit and 2-3 months later.

MEASUREMENTS AND RESULTS

In 9 of the 22 patients signs of polyneuropathy were found at the initial clinical investigation and in 7 patients at the follow-up investigation. Electrophysiologic investigation revealed signs of polyneuropathy in 18 patients initially and in 11 patients 2-3 months later.

CONCLUSION

In our patient population the frequency of the development of polyneuropathy was high (81.8%). Electrophysiologic investigation is superior to clinical neurologic examination in the detection of polyneuropathies.

Endotoxic shock after long-term resuscitation of hemorrhage/reperfusion injury decreased splanchnic blood flow and eicosanoid release

OBJECTIVE

The authors examine the hypothesis that hemorrhage/reperfusion injury predisposes the splanchnic bed to decreased prostacyclin (PGl2) release and blood flow after subsequent endotoxin challenge.

SUMMARY BACKGROUND DATA

Prostacyclin is a potent vasodilator that has been demonstrated to be an important regulator of splanchnic blood flow. Previous studies have demonstrated that during resuscitation from severe hemorrhage, there is a marked reduction in intestinal PGl2 levels, which is associated with reduced splanchnic perfusion.

METHODS

Anesthetized Sprague-Dawley rats underwent hemorrhage to a mean arterial pressure of 30 mmHg for 30 minutes followed by the reinfusion of shed blood. Then the animals were maintained on total parenteral nutrition (TPN) for 10 days, after which time they received 20 mg/kg Escherichia coli endotoxin intraperitoneally. Aortic and superior mesenteric artery (SMA) blood flow was monitored with a Doppler flow probe. The splanchnic bed was excised and perfused in vitro for measurement of venous effluent eicosanoid concentrations. Controls consisted of animals that received TPN and endotoxin but did not undergo hemorrhage and resuscitation (sham).

RESULTS

Total parenteral nutrition support of sham animals followed by endotoxin challenge did not alter splanchnic eicosanoid release or blood flow. Hemorrhage/reperfusion animals supported by long-term TPN and challenged with endotoxin demonstrated a threefold decrease in splanchnic prostacyclin metabolite (6-keto-PGF1 alpha) release and a 50% decrease in SMA blood flow.

CONCLUSIONS

Hemorrhage/reperfusion injury predisposes the splanchnic bed from rats sustained with long-term TPN to decreased release of PGl2 and SMA blood flow when challenged with endotoxin as a second injury.

Morbidity and Mortality After Traumatic Pneumonectomy: The Effect of Compromised Oxygenation and Cardiac Function

I describe the pathophysiological and hemodynamic events that occur after an emergency pneumonectomy for trauma and how they impact on subsequent mortality. Four patients were identified as requiring an emergency right pneumonectomy for trauma at a level 1 Urban Trauma Center within a 39-month period. A retrospective review of their hospital course served as the basis for our analysis. Three patients sustained gunshot wounds and one patient was a victim of blunt trauma. Hemodynamic data were available for three patients who survived more than 24 hours. All patients presented in shock and required massive transfusion. One patient died in the operating room due to air embolism and shock. After pneumonectomy, there was an increase in pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) more than 2 times normal, which coincided with a decrease in stroke volume, cardiac output, and right and left ventricular stroke work (RVSW/LVSW). The RVSW gradually increased to above normal levels by postoperative day 5, whereas the LVSWI remained below normal. Adult respiratory distress syndrome (ARDS) developed in all patients early in the postoperative period. There was evidence of oxygen delivery (DO2) dependent of oxygen consumption (VO2) and the DO2 remained below normal despite inotrope administration. The remaining three patients died 7 to 13 days after surgery due to various combinations of ARDS, cardiac failure, and sepsis. Until we have better methods to decrease PAP selectively, traumatic pneumonectomy should be avoided if possible, especially when it involves the right side or is associated with a contralateral lung injury. Early operative intervention and control of the pulmonary hilum may lessen the severity of shock. The hemodynamic changes that occur after pneumonectomy for trauma becomes additive in the presence of ARDS. This combination results in inadequate cardiac function, oxygen transport, and, ultimately, death.

A preliminary exploration of the relationship between tumour necrosis factor (TNF) and monocytic in vitro production of interleukin-1 (IL-1) and internal organ dysfunction in severely burned patients

Biological assays were adopted in this study to examine the changes in serum tumour necrosis factor (TNF) activity and blood monocytic in vitro production of interleukin 1 (IL-1) in 24 severely burned patients. The myocardial and hepatic enzymes (which included aspartate aminotransferase (AST), creatine kinase (CPK), lactate dehydrogenase (LDH), alpha hydroxybutyric dehydrogenase (alpha-HBDH) and alanine amino-transferase (ALT) and some indices of biochemical metabolism (including lactic acid (LA), total protein (TP), albumin (Alb) and colloid osmotic pressure (COP)) were simultaneously measured. The results showed an evident increase in serum TNF activity and a decrease in in vitro production of IL-1 postburn; all the changes in TNF and IL-1 were correlated significantly with those of myocardial and hepatic enzymes in MOF patients. Furthermore, there were marked fever, hypoproteinaemia, tissue ischaemic and hypoxic symptoms such as hyperlacticaemia, and signs reflecting tissue hypercatabolic states. These all suggested that TNF and IL-1 might play important roles in the development of MOF.

Acetylcysteine as a cytoprotective antioxidant in patients with severe sepsis: potential new use for an old drug

OBJECTIVE

To stimulate debate regarding a potential new use for acetylcysteine as a cellular antioxidant in severely septic patients with systemic inflammatory response syndrome (SIRS).

DATA SOURCES

A MEDLINE review of published animal, human, and laboratory studies relating to the cytopathogenic effects of active radicals in SIRS and the protective effects of acetylcysteine and glutathione.

STUDY SELECTION

Few studies were available so all studies pertinent to the objective were reviewed.

DATA EXTRACTION

Clinical and basic science data from the available trials of the effects of acetylcysteine on active radical production or active radical cell injury were extrapolated to predict the effect of acetylcysteine on human sepsis.

DATA SYNTHESIS

Severe sepsis is a major cause of SIRS. Much of the cellular injury associated with SIRS is mediated by active radicals produced by inflammatory cells that overwhelm endogenous antioxidants. Reduced glutathione is a crucial intracellular antioxidant that becomes depleted during SIRS. Regeneration of glutathione can be achieved by acetylcysteine, which unlike glutathione itself penetrates cells. In animal models of sepsis and lung injury, acetylcysteine mitigates the cytopathologic effects of SIRS. In humans, clinical benefit has been demonstrated in the SIRS of established fulminant hepatic failure.

CONCLUSIONS

The data do not as yet lead to any firm conclusions regarding the value of acetylcysteine in the management of SIRS in severe sepsis. The animal and human studies are, however, sufficiently encouraging to warrant formal trials to test the hypothesis that acetylcysteine therapy has a cytoprotective effect in sepsis.

Pneumonitis of unclear etiology in the surgical intensive care unit leading to the demise of an elderly, immunocompromised woman

Multiple system organ failure, likely an expression of a dysregulated immune system, is a common cause of death in the surgical intensive care unit (ICU). While investigational modalities of therapy are on the horizon, current treatment primarily consists of supportive care. The case of an elderly woman who was admitted to the surgical ICU after a celiac axis-superior mesenteric artery bypass, is presented. Her course was complicated by Influenza-B pneumonitis, multiple system organ failure, and, ultimately, death. The course, pathophysiology, and therapeutic modalities involved in this syndrome are discussed. Additionally, the natural history of influenza infection is reviewed.

Pentoxifylline protects splanchnic prostacyclin synthesis during mesenteric ischemia/reperfusion

This study examines the hypothesis that pentoxifylline protects splanchnic PGI2 synthesis during severe mesenteric ischemia/reperfusion injury. Anesthetized Sprague-Dawley rats (300 grams) were subjected to sham or superior mesenteric artery occlusion for 20 minutes followed by 30 minutes of reperfusion. The ischemia/reperfusion groups received either enteral allopurinol (10 mg/kg) daily for 5 days prior to ischemia, PTX (50 mg/kg) 10 minutes prior to ischemia or carrier. The superior mesenteric artery was cannulated and removed with its intact intestine (SV + SI). The SV + SI was perfused in vitro with oxygenated Krebs buffer. The venous effluent was collected and assayed for release of 6-keto-PGF1 alpha, PGE2 and thromboxane B2 by enzyme immunoassay. Severe mesenteric ischemia/reperfusion decreased SV + SI 6-keto-PGF1 alpha release by 40% compared to the sham group but did not alter release of PGE2 or thromboxane B2. Pretreatment of the animals with PTX and not allopurinol preserved SV + SI 6-keto-PGF1 alpha release at all times of perfusion to a level similar to the sham group. These data showed that severe mesenteric ischemia/reperfusion injury abolished release of endogenous splanchnic PGI2. PTX exerted a protective effect against severe mesenteric ischemia/reperfusion injury by maintaining release of splanchnic PGI2, a potent endogenous splanchnic vasodilator.

Cellular changes and time since death

Based on a hypothesis that post-mortem cellular (chiefly nuclear) changes in the white blood cells could reliably be correlated with the time interval since death, (ti), serial observations were made on the counts (total, differential) and light-microscopically observable 'degenerations' of white blood cells obtained from 30 non-refrigerated cadavers (experimental group) and similar cells obtained from 200 hospital patients (control group). While neutrophils degenerated rapidly, lymphocytes did so slowly; the eosinophils and monocytes degenerated at rates between these extremes. In cadaveric blood total counts of identifiable leucocytes on average dropped to zero by 84 hours, identifiable eosinophils and monocytes were first to 'disappear' (by 60 hours), followed by neutrophils (by 66 hours), and finally lymphocytes: identifiable lymphocytes disappeared completely at or around 84 hours from the time of death. This 'differential degeneration' was surprising but useful. Based on the use of all four characteristics--total and differential white cell counts, differential degeneration and morphology of cells--a method for a reasonably exact estimation of ti is presented. The method is appropriate for ti up to 84 hrs (3 1/2 days). Zero white cell counts (total, differential) and bizarre morphology (unidentifiable white blood cells) indicate a ti > 84 hrs. Avenues for further research are indicated.

Diagnostic laparoscopy in the intensive care patient. Avoiding the nontherapeutic laparotomy

Evaluation of a potential acute abdomen in patients who require intensive care for concurrent medical/surgical problems is often difficult due to ambiguities in the physical exam and ancillary diagnostic tests. Between August 1990, and February 1992, 25 ICU patients underwent diagnostic laparoscopy to evaluate a suspected acute intraabdominal process. Thirteen laparoscopies were negative, and 12 were positive. The overall accuracy for laparoscopy was 96% as confirmed by subsequent laparotomy, autopsy, or clinical course. Laparoscopic findings led to a change in management in nine patients (36%), leading to earlier exploration in four patients, and avoidance of laparotomy in five. No significant hemodynamic effects were noted during laparoscopy, and the procedure-related morbidity was low (8.0%). Diagnostic laparoscopy is a safe and accurate guide for managing the ICU patient with a suspected acute surgical abdomen. The use of laparoscopy can help avoid nontherapeutic laparotomy or confirm the need for operative intervention in these complex cases.

Prostacyclin regulates splanchnic blood flow during early hemorrhage/reperfusion injury

The effect of oxygen radicals on superior mesenteric artery (SMA) blood flow and splanchnic prostaglandin release was examined during early hemorrhage/reperfusion injury. Sprague-Dawley rats were hemorrhaged to 30 mm Hg for 5, 10, or 15 min without (SK5, SK10, and SK15) or with (SK10+R, and SK15+R) blood reperfusion. The SK15+R group were treated with or without superoxide dismutase (SOD 10 000 units/kg intravenously). In vivo SMA blood flow was measured continuously for 100 min by a transonic flow probe. The in vitro-perfused superior mesenteric artery and end organ intestine (SV+SI) were assayed for release of 6-keto-PGF1 alpha, thromboxane B2 (TXB2) and PGE2 by radioimmunoassay. Acute hemorrhage for 10 and 15 minutes increased SV+SI 6-keto-PGF1 alpha release 2-fold and 10-fold respectively compared to the sham (p < 0.01), which was abolished by blood reperfusion. SMA blood flow was decreased by 4% and 60% in the SK10+R and SK15+R groups respectively compared with the sham (p < 0.01). SOD treatment restored both SV+SI release of 6-keto-PGF1 alpha and SMA blood flow to control levels in the SK10+R and SK15+R groups. Oxygen-derived free radicals produced within 15 min of acute hemorrhage/reperfusion injury inhibited splanchnic PGI2 synthesis, which contributed to decreased splanchnic blood flow.

Visceral, hematologic and bacteriologic changes and neurologic outcome after cardiac arrest in dogs. The visceral post-resuscitation syndrome

We studied the post-resuscitation syndrome in 42 healthy dogs after normothermic ventricular fibrillation cardiac arrest (no blood flow) of 7.5, 10, or 12.5 min duration, reversed by standard external cardiopulmonary resuscitation (CPR) (< or = 10 min) and followed by controlled ventilation to 20 h and intensive care to 72 h. We reported previously, in the same dogs, no difference in resuscitability, mortality, or neurologic outcome between the three insult groups. There was no pulmonary dysfunction, but post-arrest cardiovascular failure, of greater severity in the 12.5 min arrest group. This report concerns renal, hematologic, hepatic and bacteriologic changes. Renal function recovered within 1 h after arrest, without permanent dysfunction. Clotting derangements at 1-24 h postarrest reflect transient disseminated intravascular coagulation with hypocoagulability, more severe after longer arrests, which resolved by 24 h after arrest. Hepatic dysfunction was transient but more severe in the animals that did not recover consciousness and correlated with neurologic dysfunction, but not with brain histologic damage. Bacteremia was present in all animals postarrest. We conclude that in the previously healthy organism after cardiac arrest of 7.5-12.5 min no flow, visceral and hematologic changes, although transient, can retard neurologic recovery.

Role of oxygen-derived free radicals on rat splanchnic eicosanoid production during acute hemorrhage

The effect of superoxide dismutase (SOD), an oxygen-derived free radical scavenger, on rat splanchnic eicosanoid synthesis was examined following hemorrhagic shock. Anesthetized male rats were hemorrhaged to 30 mm Hg for 30 minutes (Shock), killed, or treated with the shed blood (Shock plus reperfusion). The Shock plus reperfusion group was treated with saline vehicle or SOD (2500, 5000, 7500, 10,000 or 15,000 U/Kg, i.v.) 15 minutes prior to the reperfusion of the shed blood. The superior mesenteric artery was removed in continuity with the end organ intestine (SV+SI) and perfused in vitro with oxygenated Krebs-Henseleit buffer (3 ml/min at 37 degrees C). Venous effluent was measured for basal release of 6-keto-PGF1 alpha, PGE2 and thromboxane B2 at 15, 30, 60 and 90 minutes of perfusion. The SV+SI compensated for acute shock by increased release of 6-keto-PGF1 alpha (300%) (and not PGE2 or thromboxane B2) which was abolished by reperfusion of the shed blood following shock. Prior treatment of the Shock plus reperfusion group with 7500 U/Kg or more of SOD restored the increased release of SV+SI 6-keto-PGF1 alpha found following shock alone (p less than 0.05). These data provided indirect evidence that ODFRs contributed to endogenous SV+SI regulation of PGI2 synthesis and release during hemorrhagic shock and reperfusion of shed blood.

Splanchnic blood flow response to intraaortic balloon pump assist of hemorrhagic shock

Hemorrhagic shock results in marked changes in splanchnic arterial blood flow. We studied the effects of intraaortic balloon pump assist (IABP) upon splanchnic blood flow during sustained hemorrhagic shock and following volume resuscitation. Hemorrhagic shock was induced (mean blood pressure = 30 mm Hg) for 120 min in 20 dogs. Controls (n = 11) underwent resuscitation with shed blood and lactated Ringers solution only. In the study group (n = 9), IABP was begun after 60 min of hemorrhagic shock and continued throughout a 90-min period after resuscitation. Hemodynamic parameters were assessed and splanchnic blood flow was estimated (radioactive microsphere technique) at baseline, through 120 min of sustained hypotension, and during the resuscitation period. Splanchnic blood flow was significantly reduced in both the control and the IABP groups during the period of hemorrhagic shock. Interestingly, the IABP group was found to have a return to preshock splanchnic viscera perfusion without the hyperemic reperfusion phenomenon seen in control animals resuscitated with shed blood and Ringers lactate alone. IABP assist of hemorrhagic shock appears to improve vasomotor control of splanchnic blood flow in this experimental preparation of shock. This may result in less reperfusion injury to the splanchnic viscera during the resuscitation of severe hemorrhagic shock.

Is there a reliable index of glomerular filtration rate in critically ill patients?

Assessment of renal function in critically ill patients is important for appropriate individualization of dosage regimens and nutrition, but is complicated by a high incidence of acute renal failure (ARF). The most common cause of ARF in intensive care unit (ICU) patients is hypoperfusion. Other causes of ARF include intrinsic injury, nephrotoxicity, and postrenal obstruction. ARF is associated with a decreased glomerular filtration rate (GFR), reduced or maintained urine output (nonoliguric renal failure), and alterations in other commonly obtained urinary indices. Twenty-four-hour or shorter urinary creatinine clearance studies may overpredict GFR as creatinine is both filtered and secreted. The use of serum creatinine in empiric predictive equations is impaired in ICU patients because of decreases in creatinine production due to immobilization and malnutrition or increases in creatinine production due to catabolic illnesses. Adjustment of empiric methods by employing lean body weight, ideal body weight, or corrected serum creatinine values has not been evaluated against uncorrected values in this population, but is routinely performed in clinical practice. Inulin and radiolabeled substances are not practical for routine clinical use and may overpredict GFR in ARF due to backleak of large molecular-weight substances through the tubules. Comparative clinical trials have shown essentially equivalent performance of empiric methods relative to 24-hour urinary creatinine clearance in adults. No studies have compared these methods to a reference method for determination of GFR. Until conclusive data become available, clinicians should cautiously compare results from at least two independent methods of assessment to estimate renal functional impairment in ICU patients.

Peripheral nerve function in sepsis and multiple organ failure

Forty-three patients who had sepsis and multiple organ failure (critical illness) were studied prospectively to determine the incidence and severity of peripheral nerve function and to correlate such function with a number of variables. Electrophysiologic studies indicated a primary axonal degeneration of motor and sensory fibers in 30 (70 percent). Fifteen (30 percent) had the clinical signs of difficulty in weaning from assisted ventilation, weakness of limb muscles, and reduced or absent deep tendon reflexes. Full recovery from the polyneuropathy occurred among the 23 (53 percent) who survived, except three who had a very severe polyneuropathy. A peripheral nerve function index, computed from electrophysiologic measurements, showed statistically significant (p less than 0.01) negative correlations with the time in the critical care unit, and the serum glucose value; the serum albumin level showed a positive correlation. Multiple regression analyses indicated all three factors accounted for 47 percent (r2 = 0.4678) of all potential variables. In a separate analysis, the nerve function index correlated with the amplitude of the diaphragm compound muscle action potential (p less than 0.01). The results were consistent with the polyneuropathy being due to the same mechanisms that are currently postulated to cause dysfunction in this syndrome of other organ systems (including the neuromuscular respiratory system).

Reperfusion inhibits elevated splanchnic prostanoid production after hemorrhagic shock

The effect of reperfusion following hemorrhagic shock on splanchnic prostanoid release was studied. Anesthetized male rats were bled to a mean arterial blood pressure of 30 mmHg for 30 minutes and either killed or treated with shed blood for 60 minutes and then killed. The superior mesenteric arterial bed was cannulated and perfused in vitro with oxygenated Krebs. Collected venous effluent (up to 180 minutes) was analyzed for 6-keto-PGF1 alpha (PGI2 metabolite), PGE2, PGF2 alpha, and thromboxane B2 by radioimmunoassay in shock, shock plus reperfusion, and sham groups. The major prostanoid released was 6-keto-PGF1 alpha and was three times higher in the shock group compared to the sham group (p less than 0.05). Reperfusion of shed blood abolished the increase in 6-keto-PGF1 alpha found in the shock group (p less than 0.05). These data show that the attempt of the rat splanchnic bed to compensate for hemorrhagic shock by increasing release of PGI2 (potent vasodilator) was abolished during reperfusion of blood.

Role of tumour necrosis factor in the enhanced sensitivity of mice to endotoxin after exposure to lead

Heavy metals administered to animals, at doses which appear relatively innoxious by themselves, enhance susceptibility to endotoxin. The mechanisms which underly this phenomenon are not yet fully understood. In this study we investigated the role of the cytokine Tumour Necrosis Factor (TNF), an important mediator of the effects of endotoxin, in this phenomenon. First it was studied whether lead enhances sensitivity of mice to endotoxin and to TNF. Lead appeared to enhance sensitivity to both endotoxin and TNF resulting in mortality of mice at low endotoxin and TNF doses. Next we studied the influence of lead on serum TNF levels after stimulation by endotoxin. Lead treated mice showed lower TNF blood levels two hours after injection of endotoxin and lead. Six and eight hours after injection TNF levels of lead treated mice were higher compared to those of mice injected with endotoxin only. In the last part of our investigation, we studied the influence of a monoclonal hamster anti TNF antibody on the effect of combined lead-endotoxin exposure. Administration of the antibody prevents lethality completely. Our data indicate that TNF plays a central role in the phenomenon of the enhanced susceptibility of animals to endotoxin after exposure to lead. The enhanced susceptibility to endotoxin is caused by an enhanced susceptibility to TNF and possibly by a prolonged exposure to a higher level of TNF.

A study of renal damage in seriously burned patients

The incidence of acute renal failure (ARF) in severely burned patients ranges from 1.3 per cent to 38 per cent and this complication has always been associated with a high mortality rate, of between 73 and 100 per cent. At present the exact mechanisms responsible for the onset of this complication are not well known. In order to elucidate some of these mechanisms, 20 patients with severe burns were studied for 1 year in an attempt to assess the prevailing glomerular or tubular localization of renal damage; the organic or functional pattern of renal damage and the reliability and possible prognostic significance of some renal function indices. These included the fractional excretion of sodium (FeNa), the alpha-glucosidases, the leucine aminopeptidases (LAP) and the serum and urine beta 2-microglobulin. The incidence of ARF in the patients studied was 26 per cent and in all cases it was of polyuric type. We believe that renal damage very often remains undetected when the traditional testing methods are used and that only in some patients does it become severe enough to result in ARF. In contrast, some of the tests considered in our study are extremely useful and reveal an impairment of renal function long before it becomes clinically apparent.

Imaging techniques for infections in the surgical patient

Gallium-67 citrate is easy to use and readily available, but the need to delay imaging for 2 to 4 days after injection hinders rapid diagnosis. Moreover, normal gastrointestinal activity limits its usefulness in evaluating the abdomen. Labeling leukocytes with Indium-111 oxine is a time-consuming, technically involved process, yet the images obtained at 24 hours will usually reveal sites of inflammation or infection. Although the techniques have similar sensitivities, the higher specificity of In-111 makes it the superior agent for many clinical situations. When there are localizing signs or symptoms or a reason to suspect a specific body region, CT or ultrasonography is the imaging modality of choice. Guided needle aspiration can then be performed and is usually diagnostic. Radionuclide imaging with either Ga-67 or In-111 is available as an adjunct if needle aspiration cannot be performed or is inconclusive. Since it provides total-body surveillance, radionuclide imaging is particularly useful for screening when there are no localizing signs and in cases of occult sepsis or fever of unknown origin. If positive, it can direct further imaging with CT or ultrasound.

Mortality associated with multiple organ system failure and sepsis in pediatric intensive care unit

Seven hundred twenty-six patients from five pediatric intensive care units were studied to determine the association of multiple organ system failure (MOSF) with mortality and to test the hypothesis that MOSF associated with sepsis has a higher mortality rate than MOSF without sepsis. There were 177 (24%) patients with MOSF and 83 (11%) nonsurvivors of MOSF. The mortality rates for two, three, or four or more failed organ systems were 26%, 62%, and 88%, respectively (P less than 0.001). Eighty-four (47%) patients with MOSF had associated sepsis. Sepsis (both bacteremia and clinical sepsis syndrome) did not significantly increase mortality rates in the groups with organ system failure. Mortality rates for patients with sepsis before or within 24 hours of development of MOSF (early sepsis) did not differ from mortality rates for those patients with onset of sepsis more than 24 hours after developing MOSF (late sepsis, 53% vs 33%, P = NS). We conclude that underlying pathophysiologic mechanisms of MOSF other than sepsis are as important as sepsis in critically ill pediatric patients.

Prostaglandin E1 and survival in patients with the adult respiratory distress syndrome. A prospective trial

A 7-day infusion of prostaglandin E1 (PGE1), an immunomodulator, was evaluated in a prospective, randomized, placebo-controlled, double-blinded trial in surgical patients with the adult respiratory distress syndrome (ARDS). The drug seemed to improve pulmonary function--only two PGE1 patients died with severe pulmonary failure compared with nine placebo patients (p = 0.01). Survival at 30 days after the end of the infusion--the predetermined end point of the study--was significantly better in the patients given PGE1 (p = 0.03), with 15 of 21 PGE1 patients (71%) alive at this time compared with seven of 20 placebo patients (35%). Improvement in overall survival in the PGE1 patients did not reach statistical significance (p = 0.08). Overall survival in patients initially free of severe organ failure, however, was significantly better in the PGE1 patients (p = 0.03). Of the six PGE1 patients free of severe organ failure at time of entry, all survived to leave the hospital; of the 10 placebo patients initially free of severe organ failure, four survived. The drug had no serious side effects and did not potentiate susceptibility to infection. PGE1 is a promising agent for the treatment of ARDS.

A comparative evaluation of particulate and soluble glucan in an endotoxin model

Particulate glucan (P) but not soluble glucan (F) has been shown to sensitize rats to endotoxins. This phenomenon is believed to be mediated by the reticuloendothelial system (RES). The effect of glucan-P and -F on the RES, and the response of glucan-treated rats to nonlethal doses of endotoxin were investigated. Rats were injected for 5 days with 10 mg/kg of glucan-P, -F or saline. Three days later rats were either (1) injected with colloidal carbon for clearance studies, (2) sacrificed for organ histology and determination of serum glucose, plasma thromboxane (Tx) B2, and plasma 6-keto-prostaglandin (PG) F1 alpha concentrations, or (3) challenged with a nonlethal dose of endotoxin. The latter were further subdivided into groups for either 30-day survival or for sacrifice at 30 min or 4 h post-endotoxin infusion to obtain blood samples for glucose, TxB2, and 6-keto-PGE1 alpha determinations. Glucan-P induced hepatosplenomegaly and granulomatous changes within the liver and spleen. The carbon clearance halftime was markedly decreased in these animals. In glucan-P-treated rats challenged with endotoxin, elevated concentrations of both plasma prostanoids were observed as well as alterations in serum glucose levels. These changes were less pronounced in glucan-F- or saline- treated rats. Following endotoxin challenge, only 40% of glucan-P-treated rats survived 30 days whereas 100% of both the glucan-F and saline-treated rats survived. We conclude that glucan-P, in contrast to glucan-F, significantly heightens RES function and that this effect likely accounts for the endotoxin sensitivity.

Ventilatory support in patients with ARDS

Adult respiratory distress syndrome remains one of the most lethal conditions treated in surgical and medical intensive care units. Mortality rates of 50 per cent are still reported in recent reviews. Many risk factors are linked with an increased incidence of ARDS, but sepsis and direct pulmonary injury from aspiration, pulmonary contusion, and other forms of trauma are the most commonly associated risk factors. Studies implicate various cellular and chemical mediators associated with acute lung injury. Many pharmacologic agents and various forms of high-frequency ventilation are being studied for their effectiveness in treating ARDS. We consider that the standard treatment continues to be PEEP and mechanical ventilation to reverse hypoxemia linked with the pathophysiologic changes of ARDS. There are no prospective randomized studies comparing the various end points of therapy used clinically at present. We believe, however, that early intervention, with institution of ventilatory support as soon as signs of acute respiratory failure develop, may eliminate some deaths due to progressive hypoxemia leading to the full adult respiratory distress syndrome. Therapy should be started at this time and maintained while the etiologic factors are identified and treated. Minimal ventilatory support should be continued until the primary diseases have resolved and the multisystem impact of the critical illness has lessened. Weaning from inspiratory (IMV) support, manipulation of expiratory pressures (PEEP), and airway control should then be more easily accomplished and more successful in practice.

Abdominal CT scanning in critically ill surgical patients

Clinical parameters, intensive care unit (ICU) course, abdominal computed tomography (CT) scans, and the clinical decisions of 53 critically ill patients were reviewed to determine the influence of the CT scan. No scans were positive before the eighth day. Sensitivity was 48% and specificity, 64%. Seventeen (23%) scans of the 72 provided beneficial results: eight localized abscesses that were drained; nine were negative and not operated on. Five (7%) scans provided detrimental information: scan negative with abscess discovered or scan positive but negative laparotomy. Fifty (70%) scans were either of no help or not used in management. The mortality rate was 50% when CT led to an intervention, and 47% in the entire group. Hospital charges were +33,408. Personnel time and cost were 497 hours and +3658; of the total +37,066, 77% (+28,541) could be considered wasted. From these data, it was concluded that CT scans should be used to confirm abscesses, not to search for a source of sepsis.

Prostanoid production by lipopolysaccharide-stimulated Kupffer cells

Although some data suggest that macrophages in the reticuloendothelial system (RES) are important sources of thromboxane A2 (TxA2) and prostacyclin (PGI2) during endotoxic shock, we are unaware of data documenting the ability of hepatic macrophages (Kupffer cells) to release either TxA2 or PGI2 when exposed to lipopolysaccharide (endotoxin, LPS). In this study, Kupffer cells were examined for their ability to release prostaglandin E2 (PGE2), TxA2, and PGI2 following stimulation with 0, 1.0, 50.0, and 100.0 micrograms/ml of Escherichia coli LPS. Kupffer cells were obtained from rat livers by enzymatic digestion with 0.05% collagenase followed by enrichment of the macrophage population on the basis of differences in density and adherence among the various cell populations isolated. Based on several criteria (phagocytosis of opsonized sheep erythrocytes, positive staining for esterase and peroxidase, failure to replicate), 95% of adherent cells were Kupffer cells. After 4 days of incubation, cells were stimulated with various doses of LPS for 4 and 8 hr. Prostanoid concentrations in culture supernatants were determined by radioimmunoassay. Increasing doses of LPS significantly (P less than 0.001) increased the concentration of immunoreactive PGE2 (iPGE2) and iTxB2 (the stable metabolite of TxA2). The concentration of i6-keto-PFG1 alpha (stable metabolite of PGI2) increased following stimulation with 1.0 microgram/ml of LPS, but declined as the dose of LPS was increased. The results provide evidence that endotoxin-activated Kupffer cells, like other macrophage populations, release several metabolites of arachidonic acid. Kupffer cell-derived prostanoids, particularly TxA2, may be important mediators of some of the pathophysiologic manifestations of acute endotoxemia.