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Biomedical subjects

P G Pontal

Publications and source records attributed to P G Pontal.

12 recordsLinked to original sources
PubMed1987

Elimination of paraquat.

There is a striking discrepancy between the efficacy of the kidneys, haemodialysis and haemoperfusion in removing paraquat from the body and the poor prognosis of paraquat poisoning even when the blood and urine concentrations (which are good indices of concentrations in lung and other tissues) are very low. Extracorporeal elimination techniques have been used world-wide in paraquat poisoning. Do they remove paraquat effectively? Certainly. Do they increase the survival rate? Probably not. The reason being that when these techniques of elimination are initiated, potentially lethal concentrations of paraquat have already been attained in the highly vascular tissues of vital organs and in pneumocytes. The data presented here suggest that the successful treatment of paraquat poisoning will not be achieved by modification of toxicokinetics.

Animals↗
PubMed1986

Elimination of paraquat.

There is a striking discrepancy between: the efficacy of the kidneys, haemodialysis (HD) and Haemoperfusion (HP) in removing paraquat from the body and the poor prognosis of paraquat poisoning even when the blood and urine levels (which are good indices of concentrations in lung and other tissues) are very low. Extra-corporeal elimination techniques have been used worldwide in paraquat poisoning. Do they remove paraquat effectively? Certainly. Do they increase the survival rate? Probably not. The reason being that when these techniques of elimination are initiated, potentially lethal concentrations of paraquat have already been attained in the highly vascular tissues of vital organs and in pneumocytes. The data presented suggest that the successful treatment of paraquat poisoning does not depend on modification of toxicokinetics.

Adult↗
PubMed1983

[Inhalation pneumonia in toxic comas. Apropos of 200 cases with 4 deaths].

In 1946, Mendelson described 66 cases of gastric juice inhalation during obstetrical work with no mortality. Other studies studying different populations (essentially in post-operative condition) denounced a mortality from 19 to 64%. In Forensic Medicine, a bronchial regurgitation of gastric juice is denounced in 1/3 lethal toxic comas. This regurgitation can be the direct cause of the death, it also can be an epiphenomena, as suggests the high level of inhalation in agonic process of any cause: 1/4 of autopsy findings. In our department, 200 cases of inhalation pneumonia, during comatose intoxications have been registered between 1972-1982, with a frequency of 1/28 patients. All the patients were under assisted ventilation. 4 deaths occurred in this serie. This 2% mortality suggests the curability of gastric juice inhalation during comatose intoxications in not specifically respiratory-orientated intensive Care Units. These relatively good results are probably party related to the patients' recruitment: young population without underlying organic disease, with a rapid turnover and little hazards of nosocomial superinfections.

Adolescent↗
PubMed1983

[Reversibility of severe digitoxin poisoning with antidigoxin antibodies].

We report a case of severe digitoxin poisoning treated at the stage of ventricular fibrillation by infusion of FAB antidigoxin fragments with low in vitro covering properties. There were no side effects. The possibility of rapidly reversing the prognosis will permit the use of specific FAB fragments before the onset of potentially lethal cardiac arrhythmias, when these antibodies become more generally available.

Aged↗
PubMed1982

[Digitoxin poisoning: reversing ventricular fibrillation with Fab fragments of anti-digoxin antibody].

Purified Fab fragments of ovine anti-digoxin antibodies (Wellcome Foundation) were used to treat a patient who attempted suicide by absorbing 10 mg of digitoxin (serum concentration 265 micrograms/l). The poor prognosis, as assessed clinically and from serum potassium levels (7.5 mEq/l), seemed to warrant such a treatment. The weak (6.85%) cross-reactivity elicited in vitro between the anti-digoxin antibodies and digitoxin was compensated by increasing the doses, but improvement was observed with 3.6 g, i.e. about half the effective dosage initially considered. The criteria of effectiveness were clinical, electrocardiographic (reversal of the ventricular fibrillation), biochemical (simultaneous and opposite changes in extra- and intracellular potassium levels, suggesting that ATPase inhibition by digitalis is a reversible process) and toxicological: there was an increase in digitoxin serum levels suggesting displacement of the drug from tissue sites to plasma and other extracellular compartments where the Fab fragments are distributed, and Fab-bound digitoxin appeared fairly rapidly in the urine, which suggested shunting of the normal hepatic metabolic pathway.

Aged↗
PubMed1982

[Prolonged high plasma imipramine levels after acute intoxication (author's transl)].

A case of severe intoxication by tricyclic antidepressants with persistence during 14 days of abnormally high plasma imipramine levels is reported. The various factors capable of maintaining plasma imipramine at a high level are discussed. They include mechanical factors (intestinal absorption), ventilation under positive end-expiratory pressure, alterations of hepatic metabolism by other drugs such as metronidazole or cimetidine, and changes in tissue distribution. Attention is drawn to the risks inherent in the various treatments used against acute intoxications and in combined chemotherapy during intensive care generally. When such drugs are necessary, the plasma levels of those with higher toxicity should be monitored.

Adult↗
PubMed1982

[Respective roles of gastric lavage, haemodialysis, haemoperfusion, diuresis and hepatic metabolism in the elimination of a massive meprobamate overdose (author's transl)].

A case of massive meprobamate intoxication (100 g) is reported. On admission, 8 hours later, the plasma meprobamate level was 460 mg/l. The initial shock (hours 8-12) was successfully treated with blood volume expansion and dobutamine. The plasma meprobamate level, which was 340 mg/l when haemodialysis and haemoperfusion were started, fell to 110 mg/l at the end of the treatment. Recovery was uneventful. The amounts of drug eliminated by each method were as follows: (a) gastric lavages at 8 and 26 hours: 66 g; (b) haemodialysis (18-29 hours): 8.5 g; (d) haemoperfusion on Hemopur-charcoal (20-28 hours): 7.5 g (as measured by elution); (e) diuresis (26 hours): 2 g. It may be concluded from these data that sizeable amounts of drug can be extracted by haemodialysis and haemoperfusion, that gastric lavage remains the least invasive and most rewarding method of elimination, and that the role of hepatic metabolism in detoxication has to be taken into account.

Adult↗