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Biomedical subjects

R J Kimoff

Publications and source records attributed to R J Kimoff.

25 records · Page 2Linked to original sources
PubMed1991

Clinical features and treatment of obstructive sleep apnea.

OBJECTIVE: To review the clinical features and treatment of obstructive sleep apnea (OSA). DATA SOURCE AND SELECTION: All articles on OSA published in French and English between 1970 and 1990 and indexed in Index Medicus were reviewed. Studies addressing the epidemiologic features and clinical aspects of OSA were selected, and special emphasis was given to articles reporting the effects of treatment on morbidity and mortality rates. MAIN RESULTS: OSA is characterized by episodes of upper airway obstruction during sleep that result in repetitive hypoxemia and sleep disruption. OSA leads to various neuropsychologic and cardiovascular complications, including daytime hypersomnolence, cognitive impairment, systemic and pulmonary hypertension and cardiac arrhythmias. There is suggestive evidence that the death rate among affected people is increased. The true incidence of OSA is unknown, but estimates have varied from 1% upwards among men. The current treatment with the greatest overall effectiveness and acceptability is nasal continuous positive airway pressure. CONCLUSION: This common, readily treatable disorder is associated with serious complications and therefore must be widely recognized by health professionals.

Arrhythmias, Cardiac↗
PubMed1991

Nasal continuous positive airway pressure facilitates respiratory muscle function during sleep in severe chronic obstructive pulmonary disease.

Patients with chronic respiratory insufficiency due to severe chronic obstructive pulmonary disease (COPD) and presumed respiratory muscle fatigue may benefit from therapeutic maneuvers aimed at reducing the magnitude of inspiratory muscle effort. Recent work has demonstrated that continuous positive airway pressure (CPAP) can significantly reduce inspiratory effort and work of breathing in COPD patients with acute respiratory failure. Accordingly it was reasoned that prolonged CPAP administration may similarly reduce the work of breathing in stable COPD patients with chronic respiratory insufficiency, thereby allowing recovery from respiratory muscle fatigue. The purpose of this study was to determine the feasibility of employing nasal CPAP during sleep as a means of implementing this approach to reducing inspiratory muscle effort in such patients. Standard polysomnographic parameters were recorded during nocturnal administration of nasal CPAP in eight stable patients with severe COPD (FEV1 = 26.7 +/- 3.9% of predicted). Esophageal pressure, diaphragmatic (EMGdi) and parasternal intercostal (EMGic) electromyographic activity, arterial oxyhemoglobin saturation (SaO2), and transcutaneous PCO2 (PtcCO2) were also measured. Breathing pattern was determined by respiratory inductive plethysmography. In each patient an optimum level of nasal CPAP could be determined that produced consistent reductions in indices of inspiratory muscle effort without changing tidal volume or breathing frequency. Highly significant reductions in the tidal excursions of esophageal pressure and the pressure-time integral for the inspiratory muscles occurred at the optimum CPAP level in all patients. EMGdi and EMGic were similarly reduced. SaO2 and PtcCO2 were unaffected by CPAP. These results indicate that nasal CPAP can effectively reduce inspiratory muscle effort during sleep in patients with severe COPD.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Interaction of chemical and mechanical respiratory stimuli in the arousal response to hypoxia in sleeping dogs.

The role of respiratory mechanoreceptor stimuli in the arousal response to hypoxia was studied in three trained dogs. The dogs breathed through a cuffed endotracheal tube inserted through a chronic tracheostomy, and resistive loads of 8 to 49 cm H2O/L/s were added to the expiratory circuit. Arterial O2 saturation (SaO2) was measured with an ear oximeter, and isocapnic progressive hypoxia was induced by a rebreathing technique. Arousal from sleep was determined by electroencephalographic and behavioral criteria. SaO2 at arousal from non-rapid eye movement (NREM) sleep increased progressively from 67.5 +/- 4.6% (mean +/- SEM), with no added resistance to 85.2 +/- 0.5% with the highest resistance (p less than 0.01), and from 60.6 +/- 0.6 to 81.6 +/- 0.4% during REM sleep (p less than 0.01). The added resistances also increased the steady-state (normoxic) level of alveolar PCO2 (PACO2). However, when PACO2 was increased to comparable levels by the addition of dead space rather than expiratory resistance to the breathing circuit, SaO2 at arousal from hypoxia was significantly lower than during expiratory resistive loading (p less than 0.05). We therefore conclude that mechanoreceptor stimuli arising from the ventilatory apparatus may contribute substantially to the arousal response to hypoxia.

Animals↗
PubMed1990

Pulmonary denervation in humans. Effects on dyspnea and ventilatory pattern during exercise.

The role of the pulmonary autonomic nerves in the mediation of respiratory sensation is unclear. Pulmonary neurogenic mechanisms may contribute to dyspnea either directly or indirectly via an influence on the pattern of ventilation. Using human heart-lung transplantation as a model of pulmonary denervation, we studied the ventilatory response, respiratory drive (P0.1), and sensation of breathlessness (modified Borg scale) during maximal incremental bicycle exercise. The subjects were four female heart-lung transplant recipients 3 to 9 months post-transplant and 10 age-matched control subjects. The ventilatory response to increasing CO2 output (VCO2) was higher (p less than 0.001) in transplant recipients than in control subjects, such that ventilation at peak exercise was similar in the two groups despite a lower peak VCO2 in transplant recipients. The ratio of tidal volume to inspiratory capacity increased with increasing ventilation in a similar fashion in both groups. Although the respiratory rate increased more quickly in transplant recipients, it was similar at peak ventilation in the two groups. Ventilatory timing and duty cycle at half-peak and peak ventilation were similar in transplant recipients and control subjects. Dyspnea ratings were not different between the two groups at similar levels of ventilation. Dyspnea as a function of P0.1 was also similar in transplant and control groups. These results indicate that pulmonary neurogenic mechanisms play a role in determining the level, but not the pattern, of ventilation during exercise. Furthermore, these pathways do not appear to contribute significantly to the perception of breathlessness in normal humans.

Adult↗
PubMed1982

Mallory bodies in scar adenocarcinoma of the lung.

A 75 year old man presented with metastatic carcinoma of the brain. At autopsy a primary scar adenocarcinoma of the lung was found. By light microscopy the cytoplasm of the tumor cells was seen to contain hyalin masses with tinctorial properties identical to those of the Mallory bodies seen in human alcoholic liver disease and in hepatocellular carcinoma. The hyalin stained positively with anti-Mallory body antibody by the peroxidase antiperoxidase technique, and had the characteristic filamentous and granular amorphous appearance of alcoholic hyalin by electron microscopy. Our observation is of interest in light of recent information relating Mallory bodies to prekeratin, and vitamin A deficiency to lung cancer.

Adenocarcinoma↗
PubMedDate not supplied

[Obstructive sleep apnea syndromes].

Obstructive sleep apnea syndrome was first described 200 years ago but the definition of the syndrome was only developed during the last ten years (snoring, apneas during the night, somnolence, high blood pressure, changes of personality). The frequency of the syndrome is not known exactly but the pathophysiology, the morbidity and the mortality associated with the syndrome is facilitating by application of a positive airway pressure (CPAP) at the nose. Good compliance and rapid improvement of the symptomatology with practically no complications make that CPAP is the first choice for the physician in 1991.

Clinical Protocols↗