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Biomedical subjects

J W Wynne

Publications and source records attributed to J W Wynne.

At least 19 recordsLinked to original sources
PubMed1982

The effect of weight loss on sleep-disordered breathing and oxygen desaturation in morbidly obese men.

Four morbidly obese men who had been found to have significant sleep-disordered breathing and oxygen desaturation were restudied after an average weight loss of 108 kg (range 53-155 kg). In all subjects, weight loss was accompanied by a significant reduction in the number of episodes per hour of sleep-disordered breathing events. In three of the four subjects, there was improvment in the severity of desaturation accompanying abnormal breathing. The two subjects with daytime somnolence and hypercapnia prior to weight loss showed the most dramatic improvement in desaturation. This suggests that obesity is a cause, rather than an effect, of the sleep apnea syndrome.

Adult↗
PubMed1981

Physiological effects of corticosteroids in foodstuff aspiration.

Aspiration of gastric contents that contain small food particles has been shown to cause severe pneumonitis, even when the pH of the aspirate is greater than 2.5. The effects of corticosteroids on the hemodynamic and ventilatory consequences of this type of aspiration have not been investigated. Twenty healthy mongrel dogs were anesthetized and 2 mL/kg of gastric contents (pH 5.9) that contained small food particles were injected into their tracheas. Group 1 animals (controls, N = 10) received no therapy. Group 2 animals (steroid-treated, N = 10) were given methylprednisolone intravenously, 30 mg/kg, three times a day beginning one hour after aspiration. The animals were observed for 14 days, during which time there were no statistically significant differences between the groups in mortality, PaCO2, pH, systemic and pulmonary arterial blood pressures, fractional intrapulmonary shunt, or histological findings. Arterial PO2 was lower at 24 hours in group 2 dogs than in group 1 dogs. We conclude that steroids are of no benefit in the treatment of foodstuff-induced aspiration pneumonia.

Animals↗
PubMed1981

Alcohol increases sleep apnea and oxygen desaturation in asymptomatic men.

Using standard sleep techniques, we performed a placebo-controlled and randomized study to assess the effect of alcohol ingestion (2 ml/kg of body weight) on breathing and oxygen saturation during sleep. Twenty asymptomatic men volunteered for the two-night study: 11 were given a placebo on night 1, and alcohol on night 2 (group A); nine were given alcohol on night 1 and a placebo on night 2 (group B). We compared the incidence of sleep events (apnea, hypopnea and arterial oxygen disaturation) during the nights the subjects received alcohol and during the nights they received the placebo. Alcohol was associated with significant increases in the occurrence of the following: the number of sleep events (207 to 383,p less than 0.01), the events of arterial oxygen disaturation (118 to 226, p less than 0.01) and the number of apneic events (20 to 110, p less than 0.01). Alcohol had no significant effects on the number of times hypopnea occurred. Values obtained during sleep on the control night after alcohol ingestion also showed that the episodes of arterial oxygen desaturation remained statistically increased over control values before the ingestion of any alcohol (p = 0.01). These results show that in asymptomatic men alcohol ingestion increases the incidence of arterial oxygen desaturation and disordered breathing during sleep and that the increase in arterial oxygen desaturation persists for an additional night, even when no alcohol is consumed.

Adult↗
PubMed1981

Menopause, medroxyprogesterone and breathing during sleep.

Twenty-one postmenopausal women were monitored for sleep-disordered breathing and nocturnal oxygen desaturation to evaluate the contribution of progestational hormones to the occurrence of these sleep events. For approximately one month 11 subjects received 30 mg of medroxyprogesterone (MPG) daily, and 10 received placebo tablets in a randomized, double-blind controlled study. Respiration, saturation and electroencephalography were monitored during one night of sleep before and one night after therapy. Contrasted with the low incidence of disordered breathing and desaturation in premenopausal women, 71 percent of the postmenopausal women had such events. In the placebo-treated group, all measured variables of sleep and breathing were identical on the two nights, which suggested that the findings of a single night of sleep monitoring may be representative of other nights of sleep. Although several subjects appeared to show improvement with MPG, only the maximum duration of apnea was significantly reduced the second night (p less than 0.03).

Adult↗
PubMed1981

A radiographic method for measuring steady-state functional residual capacity in the supine patient. A method suitable for sleep studies.

We have devised a method to measure functional residual capacity (FRC) in the recumbent, spontaneously breathing patient. Simultaneous anteroposterior and lateral chest radiographs were exposed at the end of an exhalation, as determined by tracings of flow sensed by a nasal thermistor. The volume of the lungs was then planimetrically measured. Functional residual capacity was sequentially measured in 20 supine subjects, both by a helium dilution technique and by the radiographic technique. Planimetric measurement of FRC correlated well with the helium dilution technique, with a range of FRC measurements from 1.53 to 6.41 L (r = 0.94). This method of measuring lung volume should be useful in evaluating changes in FRC associated with different sleep stages and in explaining the mechanisms causing nocturnal oxygen desaturation in patients with chronic obstructive lung disease.

Functional Residual Capacity↗
PubMed1981

Tracheal mucosal damage after aspiration. A scanning electron Microscope study.

Aspiration of gastric contents causes severe pneumonitis, but the effects of such aspiration on the large airways have not been well studied. To evaluate the effects of gastric contents on the tracheal mucosa, 63 healthy A/J mice were anesthetized and aspirated either sterile saline (pH, 5.9) (Group I), hydrochloric acid (pH, 1.5) (Group II), canine gastric juice (pH, 1.5) (Group III), or canine gastric juice (pH, 5.9) (Group IV). Tracer studies showed that the average amount aspirated was 15% of the administered dose. Animals from each group were killed by cervical dislocation at 1, 6, 24, 48, and 72 h and 7 days after aspiration. Examination of the tracheas by scanning electron microscopy revealed normal mucosa in all Group I animals. Tracheas from Group II animals killed between 6 and 48 h after aspiration showed desquamation of the superficial cell layer with complete loss of ciliated and nonciliated cells. Regeneration was noted at 3 days with complete recovery by 7 days. Tracheas from Group III animals had similar changes but regeneration was delayed, whereas those from Group IV had mild desquamation with delayed regeneration. The lungs of group I animals were normal, and those of animals in Group II through IV showed only small widely separated areas of inflammation. We conclude that (1) gastric contents cause marked damage to the tracheal mucosa even when the amount aspirated is too small to induce a clinically significant pneumonia, (2) damage is more severe when the pH of the gastric content is low, and (3) gastric juice may contain substances that delay healing.

Animals↗
PubMed1981

The effect of nasal packing on sleep-disordered breathing and nocturnal oxygen desaturation.

Nasal obstruction is known to cause abnormal ventilation during sleep in infants, but its effects on breathing and oxygenation during sleep in adults are unknown. However, in adults, obstruction of the nose by nasal packing has been shown to cause hypoxia, and on occasion, hypercarbia and sudden death. We have investigated the pattern of ventilation and the level of oxygenation during sleep in seven patients who had nasal packs after nasal polypectomy or septoplasty. Using standard polysomnographic techniques, we monitored chest wall motion, nasal and oral airflow, and arterial oxygen saturation and sleep stages. Nasal packing either caused or worsened sleep-disordered breathing in all patients and significantly increased the number, duration, and frequency of episodes for the group as a whole. Several patients also had a greatly increased number and severity of episodes of nocturnal oxygen desaturation. This study shows that obstruction of the nose by packing causes marked alterations in breathing during sleep in adults.

Airway Obstruction↗
PubMed1981

Sleep-disordered breathing and oxygen desaturation in obese patients.

Fourteen morbidly obese subjects, referred to our institution for bypass surgery for obesity, were studied with regard to pulmonary function and respiratory patterns during sleep. The seven female patients experienced no episodes of desaturation or disordered breathing during sleep. Six of the seven male patients experienced desaturation or disordered breathing. The one who did not had hypogonadism, suggesting that testosterone may have a role in the regulation of breathing during sleep. The two patients with the most frequent episodes of apnea and lowest oxygen saturation had a clinical picture consistent with the pickwickian syndrome. This supports the relationship previously noted between the degree of hypoxia and the presence of hypersomnolence.

Adult↗
PubMed1981

Oxygen desaturation during sleep as a determinant of the "Blue and Bloated" syndrome.

Certain patients with chronic obstructive pulmonary disease may be classified as blue bloaters or pink puffers. Recent studies suggest that physiologic changes during sleep contribute to the clinical expression of these syndromes. To investigate this, we monitored four blue bloaters and six pink puffers during one night's sleep to determine the incidence of sleep disordered breathing (SDB) and of arterial oxygen desaturation. There were no significant differences between the two groups for sleep period time, awake oxygen saturation, or the number of episodes of SDB. Blue bloaters had lower baseline oxygen saturations, more episodes of arterial oxygen desaturation, and larger falls in oxygen saturation and spent more time at low levels of oxygen saturation while asleep. We propose that the degree and the duration of sleep hypoxemia of blue bloaters but not of pink puffers may contribute to early pulmonary hypertension and cor pulmonale.

Adult↗
PubMed1980

Sleep-disordered breathing and nocturnal oxygen desaturation in postmenopausal women.

Twenty postmenopausal women were monitored for disordered breathing (apnea and hypopnea) and oxygen desaturation during one night's sleep. These women were compared with 18 premenopausal women previously reported to have a low incidence of sleep-disordered breathing and nocturnal oxygen desaturation. Twelve of the 20 postmenopausal women had 102 episodes of sleep-disordered breathing and 118 episodes of oxygen desaturation, compared with only six episodes of apnea in two premenopausal women (P less than 0.01). Premenopausal women did not become desaturated. Of the postmenopausal women, 11 became desaturated; and in five of them saturation decreased to less than 85 per cent. Duration of sleep, and increased age and weight: height ratios, correlated significantly with the incidence of desaturation (P less than 0.01--P less than 0.05). Postmenopausal women resemble men with respect to disordered breathing during sleep and nocturnal oxygen desaturation. Protection from these sleep events in premenopausal women might be afforded by the respiratory stimulant effects of circulating progesterone.

Adult↗
PubMed1980

The pulmonary consequences of aspiration of gastric contents at pH values greater than 2.5.

Physiologic and pathologic responses of dogs were studied to assess the effect on the lungs of aspiration of gastric contents at a pH value greater than 2.5. Experimental solutions were administered into the lungs at a dose of 2 ml/kg. Animals were divided into 5 groups: group 1 (n = 13) received saline at a pH of 5.9; group 2 (n = 8) received hydrochloric acid (HCl) at a pH of 1.8; group 3 (n = 6) received gastric contents containing small food particles at a pH of 5.9; group 4 (n = 6) received gastric contents containing food particles at a pH of 1.8; group 5 (n = 6) received gastric contents at a pH of 5.9 from which food particles had been filtered. Arterial blood gas tension, fractional intrapulmonary shunt, and blood pressure were measured at intervals for 48 h. Animals that received gastric contents at a pH of 5.9 and severe hypoxia and increased intrapulmonary shunting that were significantly greater than those of animals receiving saline and were as severe as those of animals receiving HCl at a pH of 1.8. If food particles were in the aspirate, hypercapnia and acidosis were noted. There was pneumonitis in lung sections taken from animals in groups 2, 3, and 4, but not groups 1 and 5. These findings contradict the common belief that aspiration of gastric contents at a pH greater than 2.5 is benign.

Animals↗