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Biomedical subjects

R D Fairshter

Publications and source records attributed to R D Fairshter.

18 recordsLinked to original sources
PubMed1979

P pulmonale in status asthmaticus.

We studied 129 patients during acute, severe asthmatic attacks. Electrocardiograms showed P pulmonale in 49% of patients who had an arterial carbon dioxide tension (PaCo2) greater than or equal to 45 mm Hg and an arterial pH less than or equal to 7.37, whereas P pulmonale was present in only 2.5% of asthmatics who had a PaCO2 less than or equal to 44 mm Hg and a pH greater than or equal to 7.38 (p less than 0.001). P wave and QRS axes were 79 +/- 8 degrees and 80 +/- 20 degrees, respectively, in the presence of P pulmonale. When P pulmonale disappeared, the P wave and QRS axes shifted significantly to the left (p less than 0.001). Electrocardiographic P pulmonale persisted 12 to 60 hr after correction of hypoxemia, hypercapnia, and acidosis. In 7 patients with P pulmonale and respiratory acidosis, cardiac catheterization demonstrated normal artery pressures (PAPs) measured relative to atmospheric pressure. In 12 of these peak inspiratory pulmonary artery transmural pressures (PATPs) were increased. Since increased right heart transumural pressures could result in chamber distention, these data are consistent with the hypothesis that reversible P pulmonale in status asthmaticus is explainable on the basis of markedly negative tidal pleural pressures and increased right heart transmural pressures.

Adolescent↗
PubMed1979

Large airway constriction in allergic rhinitis: response to inhalation of helium-oxygen.

Pulmonary function results were compared in 15 allergic rhinitis and 30 normal subjects. Airways resistance (RAW) was higher (p less than 0.01) and specific conductance (SGAW) and lower (p less than 0.01) in the rhinitis group. Maximal expiratory flow (VeMax), lung volumes, and results of tests measuring airways closure, distribution of ventilation, diffusing capacity, volume of isoflow, and density-dependence of VeMax at 50% of vital capacity (deltaVeMax50) did not differ significantly between the two groups. Following inhalation of isoproterenol, RAW decreased and SGAW and VeMax increased significantly in both groups. On the other hand, delta-VeMax50 decreased significantly in the rhinitis group (p less than 0.01) and increased significantly in the control group (p less than 0.05). In addition to comparing pulmonary function in rhinitis patients and control subjects, physiologic measurements were also made on two separate occasions in the rhinitis subjects (minimal or no symptoms; very symptomatic). Although rhinitis symptomatology varied considerably (p less than 0.001), pulmonary function results were not significantly different. Hence we conclude that: (1) Rhinitis subjects have large airway constriction which does not vary with season or symptoms. (2) As in normal control subjects, airflow limitation occurs in the large airways of rhinitis subjects. (3) The predominant site of isoproterenol-associated bronchodilatation differs between allergic rhinitis and normal subjects.

Adult↗
PubMed1979

Relative sensitivities and specificities of tests for small airways obstruction.

This study compared several physiologic maneuvers for detecting small airways obstruction (SAO). Volume of isoflow best separated young smokers (average age--27.6; average cigarette consumption--9.3 pack years) from nonsmokers; this was true for comparisons of both population means and incidence of individual abnormality. However, assessment of individual abnormality by any test was greatly influenced by the criteria used to define abnormality. The best combination of test sensitivity and specificity was achieved by using the 95% confidence limits derived from a control population from the same laboratory. Even so, test results did not correlate significantly with pack years of cigarette smoking. Then, although tests for SAO are very sensitive, their prognostic value in young smokers is uncertain since abnormality presumably should correlate with extent of smoking.

Adult↗
PubMed1979

Nephrotoxicity of paraquat in man.

Renal function studies were performed in three cases of paraquat poisoning. Acute renal failure was observed in all three cases. Glomerular filtration rate improved for two patients who survived three weeks, illustrating the reversible nature of paraquat-induced acute renal failure. A mild to moderate transient proteinuria was observed during the first and second weeks following paraquat ingestion. Renal glucosuria, marked amino aciduria, and increased fractional excretion of phosphorus, sodium, and uric acid were observed. These findings, which have not been previously described in man, are indicative of proximal tubular dysfunction and parallel observations previously made in experimental animals.

Acute Kidney Injury↗
PubMed1979

Large bronchial casts.

Unusually large bronchial casts developed in four patients. In two, the casts were associated with pneumonia. In one, a large RBC cast resulted from a complication of fiberoptic bronchoscopy. Bronchial casts developed in an additional patient as a manifestation of plastic bronchitis. Although unusual, bronchial cast formation may complicate a number of hypersecretory pulmonary diseases. Therapy ordinarily includes specific measures to treat the underlying disease state and maneuvers designed to remove or facilitate the expectoration of bronchial casts.

Adult↗
PubMed1978

Pulmonary ultrastructure of the late aspects of human paraquat poisoning.

The pulmonary ultrastructure of the late aspects of a case of human paraquat poisoning is investigated and compared with normal human pulmonary ultrastructure. Alveoli in the paraquat patient are numerically reduced in comparison to the control. They are filled with edematous proteinaceous plasma-like fluid containing erythrocytes, macrophages, leukocytes, fibroblast-like cells, platelets, and fibrin. These alveoli are lined by granular pneumocytes. Interstitial areas in the paraquat patient are greatly expanded and there are no alveolar septums. Interstitial areas contain proteinaceous plasma-like material, collagen, fibrin, platelets, mature fibroblasts, plasma cells, many leukocytes, numerous erythrocytes, and capillaries. Capillary permeability seems to be enhanced in the paraquat patient either by vesicles forming transendothelial channels or pores or by disruption of endothelial cells.

Adolescent↗
PubMed1977

Large airway constriction in allergic rhinitis.

Extensive pulmonary function tests, including most of the sensitive new techniques capable of detecting small airways obstruction, were performed in 16 asymptomatic patients with allergic rhinitis and 31 normal control subjects. Mean flow rates, lung volumes, and results of tests measuring airways closure, distribution of ventilation, and diffusing capacity for carbon monoxide/alveolar volume did not differ significantly between the groups. Airways resistance (RAW) was significantly higher and specific conductance (SGAW) was significantly lower in subjects with rhinitis. Following administration of nebulized isoproterenol, RAW decreased (p less than 0.001) and SGAW increased (p less than 0.001) to mean values statistically indistinguishable from results obtained in control subjects. Individual results were normal for all tests except RAW and SGAW which were both abnormal in 3 subjects with rhinitis. The results of this investigation indicate that asymptomatic subjects with allergic have large airway (trachea and/or major bronchi) narrowing due to bronchoconstriction and no evidence of diffuse, or small airways, obstruction.

Airway Obstruction↗
PubMed1977

Volume of isoflow: effect of distribution of ventilation.

Volume of isoflow was determined in smokers and nonsmokers following one (VisoV1) and three (VisoV3) inhalations 80% helium 20% oxygen. In addition, distribution of ventilation was measured by single breath nitrogen washout and end-tidal helium concentration was determined following 1-3 breaths of a helium-oxygen mixture. In all subjects (smokers and non smokers), VisoV1 was significantly higher than VisoV3. Furthermore, VisoV1 was abnormal in 55.6% of smokers, whereas VisoV3 was abnormal in only 38.9%. Differences between VisoV1 and VisoV3 (VisoV1 - VisoV3 = deltaVisoV) were significantly larger in smokers. Non-uniform distribution of ventilation was associated with larger values of delta VisoV and lower end-tidal helium concentrations. VisoV1 is a more effective method than VisoV3 in distinguishing smokers with small airways obstruction from nonsmokers. This enhanced sensitivity can be explained by the observation that the effects of maldistribution of ventilation upon helium concentration in the late expirate are minimized after three breaths of a helium-oxygen mixture.

Adult↗
PubMed1976

Paraquat poisoning: new aspects of therapy.

Clinical, laboratory, and pulmonary physiologic features of three fatal cases of paraquat poisoning are presented. Experimental investigations and clinical experience would suggest several possible means of modifying paraquat toxicity. The following specific therapeutic interventions, several of which had previously been applied only in experimental circumstances, were used: (1) inhibition of absorption of paraquat with Fuller's Earth and catharsis by magnesium sulfate, (2) elimination of absorbed paraquat by hemodialysis with ultrafiltration and forced diuresis, (3) competition by d-propranolol for tissue binding sites, (4) modification of direct pulmonary tissue effects of paraquat by hypoxic breathing mixtures, superoxide dismutase, and corticosteroids. Treatment was unsuccessful. However, our clinical experience and data concerning paraquat concentration in body and dialysis fluids suggest a therapeutic approach aimed at preventing early and progressive tissue damage. A combination of Fuller's Earth and magnesium sulphate should be used immediately and in frequently repeated doses to prevent absorption. Diuresis and haemodialysis should be instituted as soon as possible to increase excretion. Hypoxic atomspheres should be created urgently to produce a PaO2 of 40-45 mmHg, and the use of superoxide dismutase be further investigated. It is hoped that the high mortality of paraquat poisoning will be modified by this combined approach of early and intensive treatment.

Adolescent↗
PubMed1975

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↗
PubMedDate not supplied

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↗
PubMedDate not supplied

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↗
PubMedDate not supplied

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↗
PubMedDate not supplied

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↗