Biomedical subjects
Publications and source records attributed to E T Shore.
Pseudomonas aeruginosa is an uncommon cause of community acquired pneumonia in immunocompetent hosts. We report two cases that did well once appropriate and prolonged antimicrobial therapy was initiated. They had no evidence of immune deficiency. The initial consideration was pulmonary tuberculosis in both cases given the subacute presentation, significant weight loss, and findings on chest roentgenogram.
An 83-year-old nonimmunocompromised man presented with hemoptysis that progressed to respiratory failure and death. Bronchoscopic cultures grew Aspergillus fumigatus antemortem and an autopsy confirmed multiple abscesses with Aspergillus confined to the lung.
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We studied the periodicities of ventilation in elderly subjects using digital comb filtering. Two groups of subjects were studied, those with and without sleep apnea. Measurements were made in wakefulness, stage 1-2 sleep, and where possible in stage 3-4 sleep. For each of the digital filters we calculated the average power of the oscillatory output. To compare subject groups we first specifically determined the average power in the filter with the maximum output. The mean of this measurement was greater in elderly subjects with apnea compared with those without apnea, both during wakefulness and stage 1-2 sleep. In both groups of subjects the cycle time of the major ventilatory oscillations was on the order of 40-60 s. There was no difference in this cycle time between the two groups of subjects in wakefulness or stage 1-2 sleep. Thus, whereas similar oscillatory processes occur in subjects with and without apnea, it is the magnitude of the oscillation that differs between the two groups. These conclusions are supported by analysis of the output of individual filters of the digital comb filter. In both groups, stage 1-2 sleep produced significantly increased oscillations in ventilation. Both in wakefulness and stage 1-2 sleep, significantly greater periodicities occurred in the apneic compared with the nonapneic group. In the few subjects who had sufficient data in stage 3-4 sleep for spectral analysis, ventilatory oscillations were virtually absent in this state. Our data suggest that subjects who develop apnea during sleep have an increased propensity for periodic breathing even while awake.
The effect of phasic eye movement activity on ventilation during rapid-eye-movement (REM) sleep was studied in seven healthy young adults by use of the respiratory inductive plethysmograph. Mean ventilation (VE) and ventilatory components during REM sleep were not significantly different from that seen in either stages 1-2 or 3-4 sleep. The percent of rib cage contribution to ventilation in REM sleep, 29.3 +/- 5.1%, was reduced compared with 54.4 +/- 5.8% in stage 1-2 and 52.2 +/- 4.3% in stage 3-4 sleep (P less than 0.005). When one separated breaths by the degree of associated phasic eye movement activity, it became apparent that breathing during REM sleep is very heterogeneous. Increasing eye movement activity was associated with inhibition of ventilation with a reduction in VE from 5.1 +/- 0.3 to 3.8 +/- 0.3 l/min. Tidal volume and frequency both fell, whereas inspiratory duration was unchanged. Compartmental ventilation was also affected, with the fall in the rib cage contribution from 37.8 +/- 6.4 to 15.3 +/- 5.6%. Chest wall and abdominal movement became more asynchronous as phasic-eye-movement activity increased and frank paradoxical breathing was seen.
The usual method of calibrating the respiratory inductive plethysmograph (RIP) is to have the subject breathe over a rather narrow volume range, either resting tidal volume or into a bag containing a fixed larger volume, in both the standing and supine positions. During a previous study in our laboratory using the RIP to quantify ventilation during sleep in young and elderly adults, we began to observe that the accuracy of the RIP measurements could be improved if we calibrated using a wider range of tidal volumes which encompassed the smaller breath sizes we were measuring during sleep. We therefore decided to investigate whether the size of the breaths used for calibrating the RIP was indeed important in improving the accuracy of the device. Eight healthy, nonsmoking young adult men participated in the study. Three sets of calibration factors for the RIP were determined based on low (300 to 500 ml), normal (500 to 800 ml) and high tidal volume (over 800 ml) breaths. Each of these sets of calibration factors were then used to validate three different sets of supine tidal volumes (low, normal, high). For all volumes tested, the RIP values most closely approximated the spirometric volumes when the calibration breaths and validation breaths were of the same size.
Since elderly subjects have lower chemosensitivity, we postulated that ventilation might be more state dependent in the elderly. To address this we investigated the changes in ventilation, measured by respiratory inductive plethysmography, with sleep in 12 healthy young (19-29 yr) and 13 elderly (greater than 65 yr) subjects. Ventilation was measured in representative periods in each sleep state. These data showed that there is no difference between the elderly and the young either in mean ventilation or in the variability of ventilation awake or in the different states of sleep. In both groups ventilation was variable in stage 1-2 sleep and least variable in stage 3-4 sleep. The variability in stage 1-2 sleep was due to periodic breathing (cycle time approximately 45 s) in both age groups. Although within a sleep state no differences were observed, over the night of study the elderly behaved differently from the young. Apneas occurred more frequently in the elderly, and 5 of 13 elderly met the criteria for sleep apnea syndrome compared with 1 of 12 young subjects. Apneas tended to occur predominantly in stage 1-2 sleep and seem to be an exaggeration of the periodicity that is typical of this state. Four of the elderly with apnea remained in this stage of sleep throughout the night of study. The apneic episodes usually terminated with an electroencephalogram arousal that occurred prior to or simultaneously with the onset of ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)
After the discovery of sleep apnea in 2 patients receiving chronic maintenance hemodialysis, we decided to survey all 29 male patients undergoing outpatient dialysis for symptoms suggestive of sleep apnea. 12 of 29 (41%) had positive clinical histories. 8 of these patients consented to undergo all-night polysomnography. 6 were found to have sleep apnea which was primarily obstructive in type. Recent information has implicated testosterone administration in the development of obstructive sleep apnea. Therefore, polysomnography was performed in 5 of the patients both on and off weekly testosterone injections which they were receiving to stimulate erythropoiesis. There was no change in sleep complaints or a decrease in the number of apneas and hypopneas off therapy. Sleep apnea should be considered in symptomatic male dialysis patients. Its causation is presently unknown but it does not appear to be solely related to the administration of testosterone.
Two groups of patients undergoing uvulopalatopharyngoplasty were studied. Group I patients underwent en bloc resection of tonsils and palate with the line of excision less than 1.5 cm anterior to the uvula-soft palate junction. Group II patients underwent tonsillectomy followed by palatectomy with a margin 1.5 to 2.0 cm anterior to the uvula-soft palate junction. Only 1 of 7 patients in Group I was objectively improved, whereas 11 of 13 patients in Group II improved. We conclude that a generous resection of soft palate and tonsillar tissue is mandatory for success of uvulopalatopharyngoplasty procedures.
We evaluated the effect of posture on the sensitivity and specificity of abnormalities in the flow-volume loop in 30 patients with suspected obstructive sleep apnoea. Flow-volume loops were judged as abnormal if the FEF50/FIF50 ratio was greater than 1 or if the sawtooth sign was judged to be present by at least two of three chest physicians. Detailed nocturnal recordings confirmed the presence of obstructive sleep apnoea in 17 of the 30 patients. Our results showed that both the sensitivity and the specificity of each of the flow-volume criteria for the diagnosis of obstructive sleep apnoea were higher when the loops were recorded in the supine than when they were recorded in the sitting position. The sensitivities were low, however, even with the supine posture--sawtoothing 41% and FEF50/FIF50 ratio greater than 1 47%. The highest sensitivity (71%) was obtained by considering a positive result as being the presence of either of the abnormalities in either the sitting or the supine posture. This sensitivity of the flow-volume loop was too low to recommend it as a routine screening test for the diagnosis of obstructive sleep apnoea but the presence of the sawtooth sign had a high specificity (92%) for the diagnosis of obstructive sleep apnoea. Furthermore, there was a greater fall in oxygen saturation in patients with apnoea who had sawtoothing than in those without sawtoothing. The presence of the sawtooth sign should increase the suspicion of sleep apnoea and suggest the need for further investigation. The effect of posture on the occurrence of abnormalities in the flow-volume loop suggests that position alters the configuration of the upper airway.
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We report the first two documented cases of the deliberate metoprolol overdose occurring in the United States, one of which eventually proved fatal. The potentially lethal cardiotoxic effects of this drug are illustrated and correlated with the blood and tissue levels of metoprolol. We emphasize the often sudden and rapid clinical deterioration which excessive ingestion of this drug may produce, and the need for close, careful supervision and monitoring of these patients.