[Oxygen therapy by a portable concentrator with a demand valve: a randomised controlled study of its effectiveness in patients with COPD]. / L'oxygénothérapie par concentrateur portable à valve à la demande : étude randomisée et contrôlée de son efficacité clinique chez des patients BPCO.

INTRODUCTION: There is doubt concerning the clinical effectiveness of portable oxygen concentrators with a control valve (PCDV) and their appreciation by patients. Objectives. To compare the effectiveness and appreciation of oxygen therapy by PCDV and liquid oxygen by continuous f low (O(2)Liq). METHODS: Nineteen patients with COPD were randomised to receive PCDV or O(2)Liq at rest and during a 6 minute walk test (6MWT). For each mechanism they assessed, by visual analogue scales, the convenience and portability, the noise, and the discomfort of the nasal oxygen delivery. RESULTS: The 6MW distance was 315 ± 120 m with PCDV and 325 ± 114 m with O(2)Liq (P>0.05). Dyspnoea and the desaturation induced by the 6MWT were identical with both systems (P>0.05). The time spent with a SaO(2)<90 % was 289 ± 69 s with PCDV and 242 ± 130 s with O(2)Liq (P=0.08). PCDV was noisier than O(2)Liq (P<0.05); there was no difference in convenience and portability or in nasal discomfort. CONCLUSION: The PCDV model that we tested was equally effective to O(2)Liq. However, the prescription of this type of system is a matter of personal choice.

HPLC/MS findings in a fatality involving sustained-release verapamil.

A fatality involving verapamil, a calcium channel blocker agent, is presented. A 51-year old male ingested 7200 mg of sustained-release (SR) verapamil at T0 and died 40 hours later of refractory, mixed shock and multiorgan failure. The symptoms displayed during hospitalization were quite typical and involved altered consciousness, hypotension, bradycardia, atrioventricular block, metabolic acidosis and renal failure. Verapamil and its primary metabolite, norverapamil, were assayed on eight plasma and two urine samples, successively taken between the admission to the ICU (T0 + 4 hours) and time of death, using an original high-performance liquid chromatography/mass spectrometry (HPLC/MS) procedure with verapamil-d3 as internal standard. Plasma verapamil and norverapamil levels on admission were 0.94 and 1.36 microg/mL, respectively, then verapamil remained practically unchanged throughout the hospitalization (0.85 microg/mL at T0 + 40 hours). The discussion focuses on the detrimental role of SR formulations in overdose, with special emphasis on the risk of pharma-cobezoar development already reported with SR-verapamil. To our knowledge, this is the first report of a verapamil fatality documented by repeated plasma measurements of the drug during the antemortem period.

Repeated measurements of aldicarb in blood and urine in a case of nonfatal poisoning.

A nonfatal case of poisoning involving aldicarb, an extremely toxic carbamate pesticide, is presented. A 39-year-old female ingested an unknown amount of aldicarb, together with alprazolam and sertraline. On admission to ICU (T0), she displayed marked cholinergic symptoms and a deep coma. The patient was given pralidoxime and atropine. Her condition gradually improved on days 2 and 3 and she was discharged at T0+80 h. Aldicarb was assayed by high-performance liquid chromatography on 21 blood and 8 urine samples successively taken during hospitalization. At the same time, serum pseudocholinesterase activity was followed on 21 successive samples. Blood aldicarb level was 3.11 microg/mL at T0 and peaked at T0+3.5 h (3.22 microg/mL), then followed a two-slope decay with a terminal half-life of ca. 20 h. Aldicarb was detected in all urine samples (peak level: 6.95 microg/mL at T0+31.5 h) and was still present at the time of discharge. Serum pseudo-cholinesterase activity remained low (< or = 10% of normal) until the 30th hour then rapidly increased and returned to normal after the 60th hour. The patient's clinical picture closely followed blood aldicarb levels and serum pseudo-cholinesterase activities. To our knowledge, this is the first report of an aldicarb poisoning documented by repeated measurements of the drug in the intoxicated person.

[Complications of difficult tracheal intubations in a critical care unit] . / Complications des intubations trachéales difficiles dans un service de réanimation médicale.

OBJECTIVES: This study was performed in order to evaluate the frequency of DI, the predictive factors of DI and to list the related complications. STUDY DESIGN: Prospective non randomized, open study. PATIENTS AND METHODS: All patients intubated in the critical care unit during the five months of the study were included. The previous history and clinical setting of the patients, the conditions and the complications of intubation were collected. DI was defined when the procedure required more than two laryngoscopies. RESULTS: The study included 80 patients. The rate of DI was 22.5%. The Mallampati score (p < 0.001) was the only predictive factor. The frequency of complications was 25%. This rate was 55% for DI versus 16% for easy intubations (p < 0.001). CONCLUSION: This study confirms the high incidence of DI and associated complications in critical care. We suggest the development of airway management protocols in critical care unit in order to reduce the rate of DI.

Noninvasive pressure support ventilation (NIPSV) with face mask in patients with acute cardiogenic pulmonary edema (ACPE)

OBJECTIVES: To assess (1) the short-term hemodynamic, respiratory and arterial blood gas effects of NIPSV in patients with ACPE who were likely to require endotracheal intubation, (2) the initial causes of failure and (3) the side effects and the difficulties of this technique. DESIGN: Uncontrolled, prospective clinical study. SETTING: Teaching hospital intensive care unit. PATIENTS: 26 consecutive patients with severe ACPE. INTERVENTIONS: Noninvasive ventilation via a face mask, using a pressure support mode (20.5+/-4.7 cm H2O), with an initial fractional inspired oxygen of 93.0+/-16% and a positive end-expiratory pressure of 3.5+/-2.3 cm H2O. The need to intubate the patients within 48 h was considered as a criterion of failure of the procedure. MEASUREMENTS AND RESULTS: Clinical and biological parameters were measured at 15 and 30 minutes, 1 h and 2 h and at 1 h and 2 h, respectively. There were 5 (21%) failures and 21 (79%) successes. In both the success and the failure groups, clinical and blood gas parameters improved at the first measure. In the success group, within 15 min of the start of NIPSV, pulse oximetry saturation (SpO2) had increased from 84+/-12 to 96+/-4% (p<0.001), the respiratory rate (RR) had decreased from 36+/-5.3 to 22.4+/-4.9 breaths/ min (p<0.0001) and within 1 h the arterial oxygen tension and pH, respectively, had increased from 61+/-14 to 270+/-126 mm Hg (p<0.0001) and from 7.25+/-0.11 to 7.34+/-0.07 (p<0.01) and the arterial carbon dioxide tension (PaCO2) had decreased from 54.2+/-15 to 43.4+/-6.4 mm Hg (p<0.01). There were no statistical differences between the success and failure groups for the initial clinical parameters: SpO2, RR, heart rate, mean arterial pressure. The only differences between the success and failure groups were in the PaCO2 (54.2+/-15 vs. 32+/-2.1 mm Hg, p<0.001) and the creatine kinase (CPK) (176+/-149 vs. 1282+/-2080 IU/l, p<0.05); this difference in CPK activity was related to the number of patients who had an acute myocardial infarction (AMI) (4/5 in the failure group vs. 2/21 in the success group, p<0.05). All patients with AMI in the failure group died. CONCLUSION: Among patients in acute respiratory failure, those with severe ACPE could benefit from NIPSV if they are hypercapnic, but NIPSV should be avoided in those with AMI.

Amniotic fluid embolism: a case with non-cardiogenic pulmonary edema.

We report an uncommon case of amniotic fluid embolism (AFE) in a 24-year-old woman with a 26th-week, second pregnancy. Clinical manifestations were dominated by acute respiratory distress and pulmonary edema. Recovery was complete. Early invasive hemodynamic studies showed normal function of the left ventricle with a low pulmonary artery occluded pressure. These findings are controversial to the concept of cardiogenic pulmonary edema in AFE.

Soybean oil, blackcurrant seed oil, medium-chain triglycerides, and plasma phospholipid fatty acids of stressed patients.

Thirty-six adult severe head injury and cerebral stroke patients in four intensive-care units were randomized to receive one of three enteral diets for 21 days. These diets, which supplied 45% of calories from fat, differed only in lipid composition. Diet A was comprised of 100% soybean oil, diet B contained a 50:50 (wt/wt) mixture of soybean oil and medium-chain triglycerides (MCTs), and diet C contained 42.5% MCT, 50% soybean oil, and 7.5% blackcurrant seed oils. Plasma phosphatidylcholine and fatty acid composition of plasma total phospholipids were determined before initiating treatment (day 0) and weekly throughout the study. Results indicated that at the start of the study, all patients had low linoleic acid (18:2 omega 6) levels compared with healthy subjects. Emulsion A disturbed the balance between several fatty acids of the omega 6 series, as exemplified by the significant increase in 18:2 omega 6 proportions. In contrast, both emulsions B and C introduced a less-pronounced rise in 18:2 omega 6 associated for emulsion C with a significant increase in dihomo-gamma-linolenic acid (20:3 omega 6) and docosapentaenoic acid (22:5 omega 3) in plasma phospholipids. Furthermore, 18:3 omega 6 change was significantly different between groups A and C and that of 20:3 omega 6 between group A and both groups B and C. Throughout the study, arachidonic acid (20:4 omega 6) exhibited remarkable steady-state levels regardless of the diet. This study shows that providing the injured body with high amounts of 18:2 omega 6 does not lead to high levels of its upper derivatives in plasma phospholipids.(ABSTRACT TRUNCATED AT 250 WORDS)

[Duodenal perforations by the hooks of a Kimray-Greenfield filter]. / Perforation duodénale par les crochets d'un filtre de Kimray-Greenfield.

A case is reported of a duodenal perforation by a Kimray-Greenfield filter hook in a 66-year-old female patient. This device had been inserted four years before, after a pulmonary embolism. The patient presented with epigastric pain, vomiting and extracellular dehydration with renal failure. A plain abdominal film showed the filter to be tilted 15 degrees to the left, with an opening 28 mm wide. Various investigations were carried out, none of which providing a satisfactory diagnosis. Steroid treatment (1 mg.kg-1 x day-1 of prednisone) was started before admission to intensive care. Only at that time gastroduodenoscopy showed on of the filter's hooks jutting through the duodenal wall. This perforation was located in the posterior wall of the third part of the duodenum, and was associated with an ulcer of the mucosa facing this hook. The diagnosis was confirmed by an abdominal CT scan. The hook was cut and the perforation sealed off during a first laparotomy. Twenty-six days later, the patient developed intestinal obstruction due to a haematoma of the jejunal wall. She later had a cerebrovascular accident, with status epilepticus and deep coma. She died four months after her admission. The late complications of vena caval filters are discussed. The position of these devices should be regularly checked by a plain abdominal film. Abdominal CT scanning is a useful investigation for the diagnosis of intra and extravascular complications.

When should dialysis be performed in lithium poisoning? A kinetic study in 14 cases of lithium poisoning.

Lithium kinetics were studied in 14 patients with lithium poisoning. Three patients were treated by hemodialysis. Serum lithium peak concentrations ranged between 1.4 and 9.6 mmol/L. The apparent mean serum half-life was 23.16 +/- 9 h, the mean total clearance was 26.5 +/- 13.3 mL/min and the mean renal clearance was 17.2 +/- 5.4 mL/min. The kinetic parameters were dependent on the duration of the study and on the type of the poisoning: acute, acute upon chronic or chronic. During the first 12 h after admission ten patients were in a distribution phase, three were in an elimination phase and one was in an absorption phase. The serum half-life during hemodialysis ranged from 3.6 to 5.7 h and hemodialysis clearance was 63.2 to 114.4 mL/min. The mean volume of distribution calculated in six cases was 0.63 +/- 0.09 L/kg. The evolution of the lithium pools showed a different kinetic pattern between the extra- and the intracellular pool which decreased more slowly. During hemodialysis the decrease of the extracellular pool was about twice that of the cellular pool. Among the factors which may modify lithium toxicity and kinetics, are the type of the poisoning, the presence of an underlying disease and renal impairment. No general and rigid indication for hemodialysis can be set, but the need for hemodialysis should be based on clinical and kinetic data determined during the 12 h following admission.

Kinetics of amatoxins in human poisoning: therapeutic implications.

The kinetics of alpha and beta amanitin were studied in 45 patients intoxicated with Amanita Phalloides. The amatoxins were analyzed by high performance liquid chromatography in plasma (43 cases), urine (35 cases), gastroduodenal fluid (12 cases), feces (12 cases) and tissues (4 cases). All patients had gastrointestinal symptoms and 43 developed an acute hepatitis. Two patients underwent successful liver transplantation. Eight patients, of whom three were children, died. The detection of amatoxins in the biological fluids was time dependent. The first sample was obtained at an average of 37.9 h post ingestion in the patients with positive results and at 70.6 h in the samples without detectable amatoxins. Plasma amatoxins were detected in 11 cases at 8 to 190 ng/mL for alpha and between 23.5 to 162 ng/mL for beta. In 23 cases amatoxins were detected in urine with a mean excretion per hour of 32.18 micrograms for alpha and 80.15 micrograms for beta. In 10 patients the total amounts eliminated in the feces (time variable) ranged between 8.4 and 152 micrograms for alpha amanitin and between 4.2 and 6270 micrograms for beta amanitin. In three of four cases amatoxins were still present in the liver and the kidney after day 5. Amatoxins were usually detectable in plasma before 36 h but were present in the urine until day 4. The rapid clearance indicates that enhanced elimination of amatoxins requires early treatment. Clearance of circulating amatoxins by day 4 spares the transplanted liver.

Composition of phospholipid fatty acids in red blood cell membranes of patients in intensive care units: effects of different intakes of soybean oil, medium-chain triglycerides, and black-currant seed oil.

Fatty acid composition of phospholipids in red blood cell membranes was studied in 32 severely head-injured or cerebral stroke patients receiving enteral nutrition for 3 weeks. During this study the effects of three diets differing only by their lipid composition were investigated. The daily energy intake of each patient amounted to 2950 kilocalories, of which the lipid fraction represented 45.7%. Diet A contained only soybean oil, diet B consisted of a 50% soybean oil and 50% medium-chain triglycerides mixture, and diet C was an emulsion of 50% soybean oil, 42.5% medium-chain triglycerides, and 7.5% black-currant seed oil. Our results showed no biochemical signs of fatty acid deficiency in red blood cell membranes for the patients at the beginning of the study, after a comparison with a control group of 20 healthy adults. Inhibition of delta 6-desaturase activity on linoleic acid (C18:2 omega 6) after diet A was suggested by an increase of linoleic acid without a corresponding increase of dihomo-gamma-linolenic acid (C20:3 omega 6). Replacing 50% of soybean oil by with medium-chain triglycerides (diet B) prevented this enzyme inhibition. Supply of black-currant seed oil rich in gamma-linolenic (C18:3 omega 6) and stearidonic (C18:4 omega 3) acids (diet C) induced significant increases of dihomo-gamma-linolenic and eicosapentaenoic (C20:5 omega 3) acids, without influencing arachidonic acid (C20:4 omega 6) levels. This balance was evaluated through the ratio (C20:3 omega 6 + C20:5 omega 3)/C20:4 omega 6.

[Toxicity of calcium inhibitors]. / Toxicité des inhibiteurs calciques.

Calcium antagonists decrease the intracellular concentration of calcium ions. They act essentially on the smooth vascular muscle, on the cardiac muscle and on the automatic and conducting cells in the heart. At toxic doses these effects induce hypotension, shock and disturbances of sinusal automatism and atrio-ventricular conduction. The toxicity of the different calcium antagonists varies according to their tissue specificity. The treatment of overdose includes gastric lavage, oral activated charcoal, cardiorespiratory support, especially alphamimetic vasopressors for shock or hypotension, adrenaline or cardiac pacing for atrio-ventricular block.

[Acute diltiazem poisoning: kinetic and hemodynamics study]. / Intoxications aiguës par le diltiazem: étude cinétique et hémodynamique.

The authors report three cases of diltiazem overdose with hypotension and atrio-ventricular conduction disturbances. Hemodynamic study in 2 cases showed a hyperkinetic state with a decrease of systemic vascular resistances. Diltiazem kinetics studied in 2 cases showed a plasma half life of 5.4 and 8.3 hours, a prolonged absorption until the 28th hours in one case. Treatment included gastric lavage, oral activated charcoal (2 cases), plasma expanders and in 2 cases vasopressors with alpha effects. All three patients recovered.

[Acute verapamil poisoning. 6 cases. Review of the literature]. / Les intoxications aiguës par le vérapamil. A propos de 6 cas. Revue de la littérature.

Six cases of acute verapamil poisoning are reported. The dose ingested ranged between 1.2 and 9.6 g. In all cases other drugs had also been ingested and especially betablockers in two cases. Symptomatology included a cardiogenic shock in two cases and an atrioventricular block in four cases. A hemodynamic study in one case showed a cardiogenic shock with increased systemic vascular resistances. The treatment of cardiogenic shock included artificial ventilation, several vasopressors and inotropic agents and cardiac pacing in one case. All patients recovered without sequelae. A toxicokinetic study performed in two cases showed plasma half lives of 7.9 and 13.2 hours, total body clearances of 425 and 298 ml/min. Only 2 to 4.2 per cent of the dose ingested were eliminated in urine. These results confirm the severity of verapamil overdose and the efficacy of symptomatic treatment by inotropic agents. The high rate of spontaneous elimination by hepatic metabolism does not justify drug removal by extra-corporeal methods.

Toxicokinetics in clinical toxicology.

Toxicokinetics is an essential step in clinical toxicology. The methodology is based on the same parameters which are used in pharmacokinetics. However, the interpretation and the aims are different. For each toxicon, the interpretation of kinetic data needs to take account of the spontaneous toxicokinetics, the factors of variation, the relationship kinetic data and symptoms, the severity and prognosis criteria. The evaluation of treatment has to take account of the global kinetic action of the toxicon during the intoxication and the effects on the symptomatology. The mechanism of toxicity, is an essential item in the interpretation of toxicokinetic data. By the exact knowledge of toxicokinetics, it is possible to determine for each toxicon, the relevant parameters which will be of use in clinical practice.

Reversible interleukin-2 response defects in systemic lupus erythematosus.

Limiting dilution analysis techniques were used to determine precursor frequencies for interleukin-2 (IL-2) responsive cells among the peripheral blood lymphocytes of patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis compared with healthy subjects. Response defects in SLE were found, but were of two types: reduced precursor frequencies with normal pattern of response (single-hit kinetics); and abnormal multi-hit responsiveness. These abnormalities were not more frequent statistically in those with active disease. Precursor frequencies of SLE peripheral blood lymphocytes were enhanced by resting the cells for up to 72 h prior to activation, and by adding exogenous IL-2 during the initial activation step. The IL-2 response defects of SLE are therefore reversible and may in part be secondary to other in vivo abnormalities, such as deficient IL-2 production.