Paraquat poisoning: manifestations and therapy.
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Absorption↗
Biomedical subjects
R D Fairshter
Publications and source records attributed to R D Fairshter.
Failure of isoniazid prophylaxis after exposure to isoniazid-resistant tuberculosis.
We report the failure of isoniazid chemoprophylaxis to prevent the development of active pulmonary tuberculosis and tuberculin conversion in contacts of patients infected with isoniazid-resistant strains of Mycobacterium tuberculosis. Although failure of isoniazid chemoprophylaxis has been reported rarely in contracts of isoniazid-resistant tuberculosis, the cases reported here as well as previous observations by others suggest that isoniazid chemoprophylaxis for contracts of patients with isoniazid-resistant tuberculosis may not be effective and that other agents must be considered. Initial chemotherapy of active pulmonary tuberculosis in contacts of known drug-resistant patients should be based on drug susceptibility studies in the index case.
Adolescent↗
Paraquat poisoning: an analytical toxicologic study of three cases.
Paraquat concentrations were measured in tissue, serum, urine and hemodialysate obtained from 3 patients who died 16.5 h, 22 days and 23 days after ingestion. In the patient who died 16.5 h post-ingestion, tissue paraquat levels were high. Kidney and liver had paraquat concentrations of 14 micrograms/g and 13.2 micrograms/g respectively, whereas lung tissue had a paraquat level of 3.8 micrograms/g. Low concentrations of paraquat were detectable in the tissues of the patients who died 22 and 23 days post-ingestion. Early in the poisoning, serum paraquat levels were high and large quantities of paraquat could be removed by both hemodialysis and forced diuresis. During an 8-h period, 713 mg of paraquat were removed by hemodialysis and 340 mg by forced diuresis. After the day of ingestion, little paraquat could be removed by hemodialysis or by forced diuresis; however, at all stages of the poisoning studied, hemodialysis was more effective than forced diuresis in removing paraquat from the blood.
Adolescent↗
The effects of paraquat dichloride on clinical chemistry measurements.
Although measurements in the clinical chemistry laboratory are routinely used to monitor renal and hepatic toxicity from paraquat, it is not known if paraquat, a strong oxidant, interferes with common laboratory tests. The authors analyzed the effects of paraquat (concentration range of 0 to 1000 mg/L) on the Beckman IDEAL and Technicon SMAC analyzers for 20 common analytes. Although 18 tests were unaffected by paraquat, creatinine values rose from 1.3 to 7.6 mg/dL on the SMAC and 1.3 to 3.0 mg/dL on the IDEAL. Also, LDH was unaffected, rising by 6 and 12% on the IDEAL and the SMAC, respectively. Values for these correlated positively with serum paraquat concentrations although little effect could be discerned at paraquat levels less than or equal to 10 mg/L. Thus, the magnitude of the effects were such that interference by paraquat with the measurements of creatinine and LDH can be considered insignificant in clinical circumstances.
Blood Chemical Analysis↗
Post-extubation pulmonary function tests in detection of upper airway obstruction in drug-overdosed patients.
A relatively high percentage of hypnotic-sedative drug-overdosed (HSDO) patients suffer post-extubation upper airway obstruction. Since early detection and treatment of these lesions is desirable, we studied 20 recently extubated (within 24 hours) as well as 11 non-intubated HSDO patients employing flow-volume loops and spirometry. Abnormalities in tests for upper airway obstruction were common in both groups but only in the four post-extubation patients with clinically suspected upper airway obstruction was an inspiratory plateau by flow volume loops found. In addition, three of these four patients had mid-VC ratios greater than 1.25. We conclude that the Inspiratory flow volume loop and the mid-VC ratio may help in detecting post-extubation upper airway obstruction in lethargic, HSDO patients.
Adult↗
Respiratory physiology before and after hemodialysis in chronic renal failure patients.
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Adult↗
Complications of long tracheostomy tubes.
Complications of long tracheostomy tubes are not generally appreciated. We report three cases which illustrate that long tracheostomy tubes may impinge on the carina or, less commonly, intubate the right main-stem bronchus, with resultant atelectasis of the left lung. Since larger diameter tracheostomy tubes are also longer, they are much more likely than narrow tracheostomy tubes to produce this complication. The tracheostomy tube position should be checked frequently, especially in patients who develop atelectasis and pneumonia of the left lung.
Adolescent↗
Effect of lung inhomogeneity on partial flow-volume manoeuvres.
We evaluated the effects of inhomogeneous lung emptying on the relationship of partial to maximal complete expiratory flow by obtaining pre- and post-metaproterenol maximal (MEFV) and partial flow-volume curves in normal subjects and asthmatics. Partial curves were initiated between 65-70% of vital capacity after inspiration from functional residual capacity (PEFV curve) or after deflation from total lung capacity (PEFVDI curve). Since PEFVDI curves were initiated at lower lung volumes than MEFV manoeuvres (but with a similar volume history), non-homogeneous emptying should cause higher flow on PEFVDI than on MEFV manoeuvres. Expiratory flow (Vmax) was highest on MEFV manoeuvres in normals and PEFV curves in asthmatics. Pre- and post-metaproterenol Vmax was very similar on MEFV and PEFVDI manoeuvres in both groups, although Vmax(MEFV) slightly but significantly exceeded Vmax(PEFVDI) in normals and the reverse was true in asthmatics. Lung elastic recoil did not differ significantly on MEFV and PEFVDI manoeuvres in either group. We conclude that asthmatics demonstrate inhomogeneous emptying. However, because flow-volume curves are relatively insensitive to sequences of lung emptying, inhomogeneous emptying during forced expiration only has minor effects on the relationship of partial to maximal expiratory flow.
Adult↗
Effect of a deep inspiration on expiratory flow in normals and patients with chronic obstructive pulmonary disease.
Normal control subjects and individuals with chronic obstructive pulmonary disease (COPD) were studied by measuring routine lung function tests as well as maximal (MEFV) and partial expiratory flow-volume (PEFV) curves and lung elastic recoil (Pst,L) before and after a total lung capacity (TLC) volume history. In the normal subjects: before bronchodilators airflow increased significantly, whereas Pst,L and upstream segment resistance (Rus) decreased significantly following inspiration to TLC; after administration of inhaled bronchodilators, flow rates were higher on the PEFV than on MEFV curves; nevertheless, because Pst,L decreased substantially following a deep breath, post-bronchodilator Rus was still somewhat reduced by deep inspiration. In the subjects with COPD flow rates on PEFV curves were as high or exceeded flow rates on MEFV curves in 76/100 studies; the ratio of flow rates (PEFV)/flow rates (MEFV) increased as pulmonary function worsened; as in normal subjects, Pst,L diminished in COPD subjects following deep inspiration; although flow rates increased on both PEFV and MEFV curves after bronchodilators, the increments in flow were considerably larger on PEFV maneuvers.
Adult↗
Acute respiratory failure: a rare complication of perfusion photoscintigraphy in a patient with bullous emphysema.
Acute cardiorespiratory failure occurred in a patient with advanced bullous emphysema following perfusion photoscintigraphy with radiolabeled macroaggregated albumin. Complications of perfusion photoscintography are rare. However, in patients with advanced pulmonary vascular disease, special precautions may decrease the minimal hazard associated with perfusion photoscintigraphy.
Aged↗