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Biomedical subjects

J A Kruse

Publications and source records attributed to J A Kruse.

At least 19 recordsLinked to original sources

Methanol poisoning.

Methanol ingestion is an uncommon form of poisoning that can cause severe metabolic disturbances, blindness, permanent neurologic dysfunction and death. While methanol itself may be harmless, it is converted in vivo to the highly toxic formic acid. The diagnosis is sometimes elusive and requires a high index of suspicion. Because antidotal treatment is available it is important to recognize methanol poisoning promptly. The presence of metabolic acidosis associated with an increased anion gap and increased osmol gap are important laboratory findings. Specific therapeutic measures include correction of the metabolic acidosis with sodium bicarbonate and administration of enteral or parenteral ethanol to competitively inhibit the metabolic breakdown of methanol to formic acid. Hemodialysis accelerates the elimination of both methanol and formic acid and also assists in correction of the metabolic acidosis. Experimental data suggests that administration of folic acid may be of benefit by hastening the metabolism of formic acid to carbon dioxide. Prompt institution of specific therapy can probably decrease the morbidity and mortality associated with this form of poisoning.

Acid-Base Equilibrium

Fatal rodenticide poisoning with brodifacoum.

The increased prevalence of rodents resistant to warfarin led to the development of the hydroxycoumarin anticoagulant brodifacoum. A 25-year-old man attempted suicide by consuming four boxes of d-CON Mouse-Prufe II; each box contains 42 g of bait that is 0.005% brodifacoum. He presented to a hospital nine days later with syncope, hematochezia, gross hematuria, epistaxis, anemia, and a severe coagulopathy. Radiographic studies were consistent with pleural, pericardial, and mediastinal hemorrhages. Vitamin K and fresh frozen plasma were given, and he was later discharged on oral phytonadione (vitamin K1). The patient's coagulopathy recurred, necessitating multiple plasma transfusions and prolonged treatment with oral phytonadione. Fifteen weeks after hospital discharge, he presented again with a history of additional brodifacoum ingestion. Neurologic status was initially normal, but in the emergency department he suddenly became comatose soon after emesis was induced with syrup of ipecac. Computed tomography of the brain revealed a subarachnoid hemorrhage that led to brain death less than 24 hours later. This case demonstrates the severe and prolonged coagulopathy that can result from ingestion of brodifacoum, a compound that has a toxic potency about 200-fold that of warfarin and a half-life as much as 60 times longer.

4-Hydroxycoumarins

Arterial catheterization.

Arterial catheterization is used frequently in the management of critically ill patients, both for continuous blood pressure monitoring and access to the arterial circulation to obtain frequent blood gas measurements. The procedure is usually easily accomplished at the bedside using percutaneous methods such as the Seldinger technique to cannulate the radial, brachial, axillary, femoral, or dorsalis pedis artery. Meticulous attention to aseptic technique is necessary during insertion and catheter maintenance to minimize the risk of catheter-related infection. Other potential complications include hemorrhage, ischemia, arteriovenous fistula, and pseudoaneurysm formation.

Aftercare

Temporary transvenous cardiac pacing.

Temporary cardiac pacing in the critical care setting can be a lifesaving intervention in a number of clinical situations. A variety of catheter types and pulse generators are available. Insertion techniques include the use of fluoroscopic imaging, intracavitary ECG monitoring, and blind advancement with surface ECG monitoring. This article focuses on the indications, equipment, techniques, complications, and troubleshooting of temporary transvenous cardiac pacemakers.

Cardiac Pacing, Artificial

Nasogastric and nasoenteric intubation.

Among the most commonly performed nonvascular procedures in hospitalized patients are the placement of nasogastric tubes and nasoenteric feeding tubes. Large-bore nasogastric tubes are commonly used for both diagnostic and therapeutic purposes; small-bore nasoenteric tubes are used primarily for intestinal feeding. The techniques of insertion, methods of ensuring proper positioning, and the potential complications of these devices are similar, and thus they are reviewed together in this article.

Critical Care

Hemodynamic responses to gram-positive versus gram-negative sepsis in critically ill patients with and without circulatory shock.

OBJECTIVE: To examine the hemodynamic patterns of critically ill patients with septicemia to evaluate their relationship to blood bacteriology. DESIGN: Retrospective study. SETTING: Medical ICUs of a tertiary care medical center. PATIENTS: Total of 59 critically ill patients with bacteremia: 33 with Gram-positive and 26 with Gram-negative bacteremia. MEASUREMENTS: Hemodynamic variables and mixed venous oxygen saturation (SvO2) measurements associated with the highest cardiac index measured within 72 hrs of positive blood cultures. MAIN RESULTS: No significant differences in cardiac index, mean arterial pressure, systemic vascular resistance, oxygen extraction ratio, or SvO2 were observed comparing the two groups. CONCLUSION: We were unable to demonstrate clinically important differences between the hemodynamic responses to Gram-positive vs. Gram-negative sepsis.

Adult

Risk factors for human immunodeficiency virus infection among parenteral drug abusers in a low-prevalence area.

Information is scant regarding epidemiologic risk factors for human immunodeficiency virus (HIV) infection among parenteral drug abusers (PDAs) residing in areas of low seroprevalence. A detailed interview and HIV serologic testing were conducted among PDAs hospitalized at Detroit Receiving Hospital for reasons unrelated to HIV infection. The study involved 22 seropositive (17 men, 5 women) and 52 seronegative (34 men, 18 women) drug abusers in Detroit, Michigan, an area of relatively low HIV prevalence. The interviews included inquiries regarding risk factors such as duration of drug abuse, visits to "shooting galleries," use of "hit men," needle sharing, sterile injection techniques, use of "street" antibiotics, promiscuity, visits to prostitutes, homosexuality, history of sexually transmitted diseases, and history of travel to areas of high HIV prevalence. A strong association was noted between the number of risk factors present and HIV seropositivity. The presence of any three or more risk factors was significantly associated (P less than .05) with seropositivity. Awareness of epidemiologic risk factors for HIV infection among PDAs in a low-prevalence area is useful in identification of seropositive drug abusers and is crucial in designing educational interventional strategies to interrupt viral transmission.

Adult

Double-blind study of endotracheal tobramycin in the treatment of gram-negative bacterial pneumonia. The Endotracheal Tobramycin Study Group.

A prospective, double-blind, placebo-controlled study was conducted to determine the safety and efficacy of endotracheal tobramycin (ETT) for treatment of gram-negative bacterial pneumonia. Patients were randomized to either 40 mg of tobramycin or a placebo instilled endotracheally every 8 h. Patients also received intravenous tobramycin plus either cefazolin or piperacillin. Of 85 patients enrolled, 41 were assessable. Most microbiologic diagnoses were made by endotracheal aspiration with strict grading criteria. The clinical-radiographic responses of patients and standard demographic data were recorded. Pseudomonas aeruginosa, "multiple pathogens," and Klebsiella-Enterobacter-Serratia-Citrobacter species were isolated in 41, 32, and 15% of the instances, respectively. Causative pathogens were eradicated from sputum significantly more frequently by patients who received ETT (P less than 0.05). However, no significant differences were noted in the clinical outcomes of the two study groups. No local adverse reactions attributable to the administration of this agent were observed, but four patients had supraventricular tachycardia, compared with none who received the placebo (P = 0.053). ETT may be considered as adjunctive therapy for seriously ill individuals.

Adult

Lactate levels as predictors of the relationship between oxygen delivery and consumption in ARDS.

We reviewed the changes in Do2 and Vo2 in 58 patients with ARDS after interventions which included fluid loading, blood transfusion, and PEEP. After a significant change in Do2, patients with lactic acidosis (lactate level greater than 2.4 mmol/L) exhibited significant corresponding changes in Vo2 (p less than 0.001); however, no change in Vo2 was observed in patients without lactic acidosis (1-beta greater than 0.8). We conclude that a biphasic pattern of oxygen utilization in patients with ARDS emerges when subsets of patients with and without lactic acidosis are compared. Lactic acidosis, a marker of anaerobic metabolism, may be a characteristic of patients with ARDS who exhibit changes in Vo2 that are dependent on changes in Do2.

Humans

Rapid correction of hypokalemia using concentrated intravenous potassium chloride infusions.

There are conflicting recommendations regarding the use of intravenous potassium chloride infusions for acute correction of hypokalemia. We examined the effects of 495 sets of potassium chloride infusions administered to a medical intensive care unit population. The infusion sets consisted of one to eight consecutive individual infusions, each containing 20 mEq of potassium chloride in 100 mL of saline administered. The mean preinfusion potassium level was 3.2 mmol/L, and the mean postinfusion potassium level was 3.9 mmol/L. The mean increment in serum potassium level per 20-mEq infusion was 0.25 mmol/L. No temporally related life-threatening arrhythmias were noted; however, there were 10 instances of mild hyperkalemia. Our data endorse the relative safety of using concentrated (200-mEq/L) potassium chloride infusions at a rate of 20 mEq/h via central or peripheral vein to correct hypokalemia in patients in the intensive care unit.

Catheterization, Central Venous

Triple- vs single-lumen central venous catheters. A prospective study in a critically ill population.

To evaluate a new multilumen central venous catheter we prospectively compared the infection rates of 63 single-lumen and 157 triple-lumen catheters in 145 critically ill patients. Using acute physiology scores, severity of illness was shown to be similar in the two patient groups. There were no significant differences in the rate of catheter colonization or catheter-related sepsis comparing single-lumen with triple-lumen catheters. However, the use of total parenteral nutrition or insertion at the femoral vein site significantly increased the rate of colonization. The only factor that was clearly associated with catheter sepsis was the duration of catheterization. Catheter sepsis increased from 1.5% to 10% when the period of catheterization exceeded 6 days. We conclude that the use of triple- and single-lumen central venous catheters in critically ill patients entails similar risks of infection.

Adult

Relationship between the apparent dissociation constant of blood carbonic acid and severity of illness.

The Henderson-Hasselbalch equation is commonly used to calculate plasma bicarbonate and CO2 content (tCO2) from blood gas measurements and an assumed constant value of the apparent dissociation constant of blood carbonic acid (pK'). Several studies have reported pK' to be variable in critically ill patients. We prospectively compared the pK' of patients in an intensive care unit to their severity of illness. Blood specimens were analyzed for pH, Pco2, and tCO2, and the results were used to calculate pK'. The tCO2 was also calculated from this equation by means of the measured pH and Pco2 and from an assumed constant pK'. Severity of illness was evaluated with the acute physiology score and the Therapeutic Intervention Scoring System. A total of 2004 specimens were analyzed; they had a mean pK' of 6.126. A strong correlation was shown between calculated and measured tCO2; however, there was essentially no correlation between disease severity and pK'. We conclude that bicarbonate and tCO2 can be accurately calculated in critically ill patients.

Blood Gas Analysis

Constancy of blood carbonic acid pK' in patients during cardiopulmonary resuscitation.

Previous studies have suggested that the apparent dissociation constant of blood carbonic acid (pK') may actually vary in acutely ill patients. We prospectively compared the pK' of healthy control subjects to that of patients undergoing cardiopulmonary resuscitation (CPR). Arterial blood obtained from 20 patients undergoing CPR and from 30 healthy volunteers was analyzed for Na+, pH, PCO2, and total CO2 content (tCO2). pK' was calculated from this data, using the Henderson-Hasselbalch equation. Total CO2 was then calculated in the CPR patients, using this equation and the control pK'. Mean pK' was 6.109 +/- 0.004 (SEM) for the control group and 6.123 +/- 0.007 for the CPR group (p = NS). In the CPR group, calculated tCO2 was not significantly different from measured from tCO2, and the correlation between calculated and measured tCO2 was 0.99. In patients undergoing CPR, pK' does not differ significantly from normal, and tCO2 can be accurately estimated with the Henderson-Hasselbalch equation.

Adult

Significance of blood lactate levels in critically ill patients with liver disease.

Lactic acidosis unrelated to tissue hypoxia has been described in patients with liver disease. This raises questions regarding the utility of the arterial lactate level as an indicator of tissue hypoperfusion in critically ill patients with hepatic dysfunction. The incidence of hyperlactatemia in a group of critically ill patients with liver disease and its association with clinical indicators of circulatory shock as well as hospital mortality were examined. The medical records of all patients admitted to the medical intensive care unit of Detroit Receiving Hospital between July 1, 1984, and June 30, 1985, with parenchymal liver disease and a total bilirubin level of more than 2 mg/dl were reviewed. Patients were excluded if lactate was not assayed. The severity of liver disease was assessed by Child's classification. Shock was defined as a systolic blood pressure of less than 90 mm Hg and at least two of the following: urine output of less than 20 ml/hour, evidence of decreased skin perfusion, or acutely altered mentation. These criteria were met in 35 patients; three patients had two medical intensive care unit admissions separated by more than one week. There were two patients in Child's class A, three in class B, and 30 in class C. Shock was identified in 27 of the 38 medical intensive care unit admissions. In the group with shock, the maximal lactate level ranged from 1.2 to 30 mM (mean, 9.6). The lactate level was significantly lower (p less than 0.0005) in the group without shock, ranging from 0.6 to 2.0 mM (mean, 1.3). The mean bilirubin level was significantly higher in the group without shock (16.7 mg/dl) than in the group with shock (8.5 mg/dl). A maximal arterial lactate concentration of more than 2.2 mM was significantly associated with hospital mortality. Thus, lactic acidosis in critically ill patients with liver disease is associated with clinical evidence of shock and with increased hospital mortality.

Acidosis, Lactic