Gentle blood aspiration and tube cushioning reduce pneumatic tube system interference in lactate dehydrogenase assays.

Background: Use of a hospital pneumatic tube system may be associated with measurement errors.

Methods: A venous blood sample was collected from 79 patients into a pair of lithium heparin tubes; one tube was sent to the laboratory by porter and the other was sent via the pneumatic tube system. Plasma lactate dehydrogenase concentrations were then assayed.

Hypertonic sodium lactate improves fluid balance and hemodynamics in porcine endotoxic shock.

Introduction: Based on the potential interest in sodium lactate as an energy substrate and resuscitative fluid, we investigated the effects of hypertonic sodium lactate in a porcine endotoxic shock.

Methods: Fifteen anesthetized, mechanically ventilated pigs were challenged with intravenous infusion of E. coli endotoxin.

Impact of endotoxin challenge in obese pigs.

Studies exploring the influence of obesity on septic shock remain limited and controversial. Pigs were chosen as a clinically relevant species, resembling to humans in various functions. We hypothesize obesity may impair porcine acute endotoxic shock.

Effects of esmolol on systemic and pulmonary hemodynamics and on oxygenation in pigs with hypodynamic endotoxin shock.

Purpose: The aim of this experimental study is to investigate cardiovascular tolerance of blockade of beta-adrenergic receptors in an endotoxin model.

Design: Prospective, randomized, controlled study.

Setting: Animal laboratory in a university medical center.

Pneumatic transport is critical for leukaemic patients with major leukocytosis: what precautions to measure lactate dehydrogenase, potassium and aspartate aminotransferase?

False elevations of plasma lactate dehydrogenase (LDH), potassium and aspartate aminotransferase (AST) have been described, in relation to haemolysis, occurring most often by mechanical release during phlebotomy or specimen processing. We present the cases of two leukaemic patients with severe hyperleukocytosis for whom LDH, potassium and AST were dramatically but falsely elevated. This false elevation was not caused by haemolysis but could be related to white cells lysis during transport through a pneumatic transportation system, enhanced by a specific fragility of leukaemic cells.

Evaluation of BCECF fluorescence ratio imaging to properly measure gastric intramucosal pH variations in vivo.

Our purpose is to evaluate intramucosal gastric pH video imaging by 2('),7(')-bis(carboxyethyl)-5,6-carboxyfluorescein (BCECF) fluorescence ratio techniques. We use a video endoscopic imaging system and BCECF as the pH fluorescent probe. Systemic in vivo pH variations are studied in 10 pigs: five in the control group and five with respiratory acidosis induced through rebreathing.

Evaluation of auto-regulated inspiratory support during rebreathing and acute lung injury in pigs.

Background: Auto-regulated inspiratory support mode (ARIS) is an original closed-loop pressure-support system that regulates the slope ("A") and the initial level ("B") of the applied inspiratory pressure, in order to achieve an optimal minute ventilation under constrained respiratory frequency, tidal volume, and maximum inspiratory airway pressure. The servo-controlled design results in a more or less decreasing applied pressure.

Objective: The aim of this study was to evaluate the ARIS behavior, compared with pressure-support ventilation at a constant applied pressure.

Cefepime-induced neurotoxicity: an underestimated complication of antibiotherapy in patients with acute renal failure.

Objectives: To describe five new cases of life-threatening cefepime-induced neurotoxicity observed in a 2-year period.

Setting: A university intensive care unit.

Patients: Five patients recently treated with cefepime, admitted for seizures and coma.

Escherichia coli endotoxin reduces cytochrome aa3 redox status in pig skeletal muscle.

Objective: To assess the effect of endotoxin on cytochrome aa3 (Caa3) redox status in a controlled blood flow preparation of pig isolated hindlimb, at a constant oxygen delivery (Do2limb) (constant flow period) and during progressive ischemia (decreasing flow period).

Design: Randomized, controlled experimental study.

Setting: University hospital experimental laboratory.

Redox status of cytochrome a,a3: a noninvasive indicator of dysoxia in regional hypoxic or ischemic hypoxia.

Objective: Multiwavelength near infrared (NIR) spectrophotometry can monitor the redox state of cytochrome a,a3 (cyt a,a3) in vivo. Because cyt a,a3 is the most immediate reductant of oxygen, this technique has been proposed to evaluate tissue oxygenation. The purpose of this study was to examine the relationship between cyt a,a3 oxidation level as an indicator of dysoxia and oxygen uptake (VO2) when oxygen delivery (DO2) was progressively lowered in an in situ vascularly isolated hindlimb.

Effects of a combined antithrombin III and protein C supplementation in porcine acute endotoxic shock.

Antithrombin III (ATIII) and protein C (PC) are major inhibitors of the coagulation cascade and might regulate the cytokine network. We tested the possibility that a combined supplementation using these two inhibitors might have synergistic effects on sepsis-induced disseminated intravascular coagulation and shock. Hemodynamics, coagulation parameters, tumor necrosis factor (TNF) alpha, and interleukin 6 levels were measured in pigs submitted to a bolus infusion of Escherichia coli endotoxin (lipopolysaccharide).

Effects of inter-alpha-inhibitor in experimental endotoxic shock and disseminated intravascular coagulation.

We investigated the effects of human inter-alpha-inhibitor (I alpha I) on hemodynamics, oxygenation, and coagulation parameters in a porcine model of endotoxic shock. Four groups of six animals were studied: (1) control, (2) I alpha I group receiving 30 mg/kg I alpha I over 30 min, (3) LPS group receiving 5 micrograms.kg/min Escherichia coli endotoxin over 30 min, and (4) LPS + I alpha I group receiving 30 min after endotoxin 30 mg/kg/30 min I alpha I.

Effects of N omega-nitro-L-arginine methyl ester on the endotoxin-induced disseminated intravascular coagulation in porcine septic shock.

Objectives: Nitric oxide is known to prevent platelet aggregation and clot formation. Inhibitors of nitric oxide synthase might promote or enhance endotoxin disseminated intravascular coagulation. The present study was designed to evaluate the effects of the arginine analog, N omega-nitro-L-arginine methyl ester (L-NAME), on the endotoxin-induced disseminated intravascular coagulation in a porcine model of septic shock.

ATP-sensitive K+ channel blockade impairs O2 extraction during progressive ischemia in pig hindlimb.

Tissues maintain O2 consumption (VO2) when blood flow and O2 delivery (DO2) are decreased by better matching of blood flow to meet local cellular O2 demand, a process that increases extraction of available O2. This study tested the hypothesis that ATP-sensitive K+ channels play a significant role in the response of pig hindlimb to ischemia. We pump perfused the vascularly isolated but innervated right hindlimb of 14 anesthetized pigs with normoxic blood while measuring hindlimb DO2, VO2, perfusion pressure, and cytochrome aa3 redox state.

Use of capnography in diagnosis of pulmonary embolism during acute respiratory failure of chronic obstructive pulmonary disease.

In chronic obstructive pulmonary disease (COPD) patients, there is a difference between PaCO2 and end-tidal partial pressure of CO2 (PetCO2). This gradient P(a-et)CO2 is due to ventilation/perfusion mismatching and deadspace, and is usually abolished by forced and prolonged expiration. We hypothesized that this gradient might not be canceled by forced expiration in the case of acute respiratory failure (ARF) related to pulmonary embolism (PE).

Meningococcemia and purpura fulminans in adults: acute deficiencies of proteins C and S and early treatment with antithrombin III concentrates.

It has been recently suggested that an acquired deficiency of proteins C and S could contribute to the pathogenesis of meningococcemic purpura fulminans (PF) in children. Our study was designed to measure the levels of antithrombin III (AT III), protein C, and protein S during adult PF and to determine the effects of an early infusion of high doses of AT III concentrates on clinical and biological alterations of PF. We studied five consecutive adult patients with meningococcemia (type B) and PF.

Computer-assisted evaluation of respiratory data in ventilated critically ill patients.

In intensive care unit, a lot of data are currently available but remain unused by nurses and residents because of complexity of analysis. We have developed a system for interpretation of respiratory data (RESPAID) in order to improve monitoring of patients under respiratory support and also to provide a high level of information. RESPAID is a real-time system which interprets quantitative and qualitative aspects of the usual respiratory data at different levels of information.

Carbon dioxide mandatory ventilation (CO2MV): a new method for weaning from mechanical ventilation. Description and comparative clinical study with I.M.V. and T. tube method in COPD patient.

We describe a new technique specially designed for weaning from mechanical ventilation: carbon dioxide mandatory ventilation (CO2MV). CO2MV is based on feedback between end tidal expired partial pressure of carbon dioxide and ventilatory mode, controlled or spontaneous. In order to evaluate its real interest we performed a randomized prospective study, CO2MV vs Intermittent Mandatory Ventilation (IMV) and T.

Decrease of angiotensin-converting enzyme activity after plasma exchange.

We measured sequential changes in serum angiotensin-converting enzyme (ACE) in 12 ICU patients undergoing plasma exchange (PE) with plasma substitutes (albumin-Polygelin). A dramatic decrease in serum ACE activity was observed after each of the 51 PE procedures. Repeated PE procedures resulted in almost a total depletion of serum ACE, which returned to normal ranges in 4 to 10 days.

Compared evolution of plasma fibronectin and angiotensin-converting enzyme levels in septic ARDS.

Serum angiotensin converting enzyme (serum ACE) levels and plasma fibronectin levels were measured daily in 46 septic patients during a ten day period. Thirty-eight patients developed ARDS; 28 survived (group 1), ten died (group 2), eight patients had no features of ARDS and survived (group 3). Sequential measurements of ACE and fibronectin levels were compared and plotted against indexes of respiratory impairment: PaO2 max Qs/Qt, static compliance and VD/VA ratio.

Angiotensin-converting enzyme in human adult respiratory distress syndrome.

Angiotensin-converting enzyme (ACE) levels, complement activation, and intravascular coagulation were studied in 36 patients with adult respiratory distress syndrome (ARDS) (17 aseptic, 19 septic), in order to investigate the possible interrelations among ACE, immunologic data, and hematologic findings. The severity of respiratory impairment was assessed with measurements of mechanical and gas exchange functional qualities of the lung. Serial measurements of ACE could be done in 14 patients during an eight-day period.