Biomedical subjects

K Gleeson

Publications and source records attributed to K Gleeson.

26 records · Page 2Linked to original sources

PubMed1990

The do-not-resuscitate order. Still too little too late.

We reviewed the records of 274 consecutive deaths at the Milton S. Hershey Medical Center, Hershey, Pa, occurring through May 1988 to examine the approach of physicians, patients, and families in making the decision to invoke the "do-not-resuscitate" order. Of these 274 patients who died, 171 (62%) had do-not-resuscitate orders. Of these 171 patients, 86 (50%) were judged fully mentally competent on admission to the hospital; 44 (51%) of these 86 fully competent patients were included in the decision to withhold resuscitative efforts. In the remainder, the family was usually involved in the decision without input from the patient. Only 6 patients (4%) were admitted to the hospital with a preexisting do-not-resuscitate order. For the remainder, the do-not-resuscitate order was written a mean of 8.5 days following admission and 3.3 days before death. Documentation of this order with a specific progress note was universal. The principle reason cited for a do-not-resuscitate order was the presence of irreversible terminal disease in 52% and an unacceptable quality of life in 33%. When considered separately, patients with a principle diagnosis of malignant neoplasm had a do-not-resuscitate order written 80% of the time. Of 88 such patients, 48 (55%) were fully competent at admission. In turn, 36 (75%) of these patients participated in the do-not-resuscitate decision. Nursing activities were quantified for the 24 hours preceding and the 24 hours following the do-not-resuscitate order. No difference could be found comparing these two periods whether the comparison was made on the general hospital ward or in the intensive care unit.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1989

Chemosensitivity and the ventilatory response to airflow obstruction during sleep.

There is an accumulating body of evidence which suggests that chemical control of breathing can play a role in destabilizing respiratory rhythm during sleep. We hypothesized that the sleeping ventilatory response to hypercapnia (HCVR) and/or hypoxia (HVR) would predict respiratory events following release of inspiratory airway obstruction (IAO) in normal men during non-rapid-eye-movement (NREM) sleep. We therefore measured HCVR, HVR, and ventilation for three breaths preceding and eight breaths following three totally obstructed inspirations in eight normal subjects during NREM sleep. After IAO, we generally observed transient hyperventilation that resulted in hypocapnia and prolonged expiratory time. We found the initial increase in inspiratory minute ventilation (VI) following IAO to be correlated with HCVR (r = 0.72, P less than 0.05) but not HVR. In addition, the maximum decrease in PCO2 below base line was also related to HCVR (r = 0.83, P less than 0.05). This decrement in PCO2 predicted the subsequent prolongation in expiratory time (TE, r = 0.83, P less than 0.05) that was frequently observed. HCVR tended to predict the prolongation of TE, at the nadir of CO2 (r = 0.69, P = 0.057). In conjunction with this hypocapnia and prolongation of TE, hypoventilation with falling VI was often observed followed by periodic hyper- and hypoventilation. These results suggest that high HCVR may result in ventilatory overshoot following IAO and may contribute to ventilatory instability during sleep.

Airway Obstruction↗

PubMed1987

Altitude acclimatization: influence on periodic breathing and chemoresponsiveness during sleep.

Although the influence of altitude acclimatization on respiration has been carefully studied, the associated changes in hypoxic and hypercapnic ventilatory responses are the subject of controversy with neither response being previously evaluated during sleep at altitude. Therefore, six healthy males were studied at sea level and on nights 1, 4, and 7 after arrival at altitude (14,110 ft). During wakefulness, ventilation and the ventilatory responses to hypoxia and hypercapnia were determined on each occasion. During both non-rapid-eye-movement and rapid-eye-movement sleep, ventilation, ventilatory pattern, and the hypercapnic ventilatory response (measured at ambient arterial O2 saturation) were determined. There were four primary observations from this study: 1) the hypoxic ventilatory response, although similar to sea level values on arrival at altitude, increased steadily with acclimatization up to 7 days; 2) the slope of the hypercapnic ventilatory response increased on initial exposure to a hypoxic environment (altitude) but did not increase further with acclimatization, although the position of this response shifted steadily to the left (lower PCO2 values); 3) the sleep-induced decrements in both ventilation and hypercapnic responsiveness at altitude were equivalent to those observed at sea level with similar acclimatization occurring during wakefulness and sleep; and 4) the quantity of periodic breathing during sleep at altitude was highly variable and tended to occur more frequently in individuals with higher ventilatory responses to both hypoxia and hypercapnia.

Acclimatization↗

PubMed1986

Effect of inspiratory nasal loading on pharyngeal resistance.

Nasal obstruction has been shown to increase the number of apneas during sleep in normal subjects and in some may actually cause the sleep apnea syndrome. We postulated that the pharynx may act as a Starling resistor, where increases in negative inspiratory pressure result in elevated resistance across a collapsible pharyngeal segment. To test this theory in normal subjects we studied 10 men and 10 women during wakefulness. Pharyngeal resistance (the resistance across the airway segment between the choanae and the epiglottis) was determined in the normal state and with three inspiratory loads added externally. Flow was measured using a pneumotachometer and a sealed face mask; epiglottic pressure by a latex balloon placed just above the epiglottis and choanal pressure by anterior rhinometry. Pharyngeal resistance (measured at 300 ml/s) could thus be determined. Base-line inspiratory pharnygeal resistance was 1.6 +/- 0.2 cmH2O . l-1 . s. This increased to 2.3 +/- 0.3, 2.8 +/- 0.4, and 2.9 +/- 0.4 cmH2O . l-1 . s, respectively, with the addition of 1.3, 2.7, and 6.7 cmH2O . l-1 . s inspiratory load. The resistance at each level of load was significantly different from the base-line resistance determination (P less than 0.05) but not different from each other. We conclude that added nasal resistive loads during inspiration cause an increase in pharyngeal resistance during wakefulness but that this resistance does not increase further with additional increments of load.

Adult↗

PubMed1986

Role of the nose in resistive load detection.

Previous resistive load detection (RLD) studies have ignored the nose, the usual route of breathing. Weber's law predicts the delta R50 (the added load detectable on 50% of presentations) to be a fixed percent of the background resistance (R0) and thus the delta R50/R0 ratio (the Weber fraction) is constant. We have noted the nose to be sensitive to added load, we wondered if the nose might play a role in RLD. To determine whether this was true and to characterize the effects of changes in R0 in the range of normal nasal resistance (RN), we determined R0 and delta R50 using standard techniques under the following conditions: nose vs. decongested nose, nose vs. nose with added external R0 (3.0 and 8.0 cmH2O X l-1 X s), nose vs. anesthetized nose, nose vs. mouth, and mouth vs. mouth with added load (3 cmH2O X l-1 X s). We found that decongestant decreased RN [4.3 +/- 0.6 (SE) to 3.1 +/- 0.5 cmH2O X l-1 X s, P less than 0.05] and delta R50 (1.7 +/- 0.5 to 1.1 +/- 0.3 cmH2O X l-1 X s, P less than 0.05). When an external load of 3 cmH2O X l-1 X s was added to the nose, delta R50 did not change significantly (1.4 +/- 0.2 to 1.1 +/- 0.2 cmH2O X l-1 X s), but the Weber fraction decreased (0.28 +/- 0.05 to 0.15 +/- 0.03, P less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1986

Breathing route during sleep.

Nasal obstruction has been associated with apneic episodes during sleep. However, the normal distribution of nasal and oral air flow while asleep has not been investigated. To determine the normal route of ventilation during sleep, we studied 7 healthy men and 7 healthy women using a sealed face mask that mechanically separated nasal and oral air flow. Standard sleep staging techniques were employed. The subjects slept 297 +/- 29 (SEM) min, with a mean of 197 +/- 15 min of ventilation recorded. Ventilation was decreased during sleep as has been previously demonstrated. However, during sleep, we found that men breathed a greater percentage of total ventilation through the mouth (29.0 +/- 8.2%) than did women (5.0 +/- 1.0%, p less than 0.02). The same trend applied during wakefulness but did not reach significance (p = 0.06). Although none was symptomatic, 4 subjects, all men, had more than 3 apneas per hour. These 4 men had a greater percentage of mouth ventilation (37.3 +/- 19.0%) than did the other 10 subjects with few or no apneas (8.1 +/- 2.7%, p less than 0.02). It was also noted that increasing age in men was associated with an increasing percentage of mouth ventilation (r = 0.83 p less than 0.03) but this relationship was not observed in women. We conclude that mouth breathing may be associated with apneas during sleep and that breathing through the mouth occurs commonly in men, particularly in those who are older. This suggests that nasal breathing may be important in the maintenance of ventilatory rhythmicity during sleep.

Adult↗

PubMedDate not supplied

Pneumonia in the intensive care unit setting.

Nosocomial pneumonia is a common and serious occurrence in the ICU. It most often results from aspiration of oropharyngeal secretions that have become colonized with pathogenic enteric gram-negative bacilli. Colonization occurs in association with acute and chronic illness and particularly with therapy that includes nasogastric or endotracheal tubes, H 2 blocking antacid drugs, or antibiotics; aspiration is increased by anesthesia, sedative drugs, and upper airway instrumentation. The diagnosis of ICU-acquired pneumonia is complicated greatly by the nonspecificity of clinical and laboratory data, and the difficulty in distinguishing the organisms producing infection from those merely colonizing the airway when using routine culture techniques. Among specialized diagnostic techniques, quantitative culture of specimens obtained with the protected sampling brush offers the most promise in establishing a specific microbacteriologic diagnosis of nosocomial pneumonia. Empirical treatment with broad spectrum antibiotics is frequently necessary when a specific diagnosis cannot be made. The poor outcome associated with nosocomial pneumonia, regardless of treatment, suggests that methods to prevent dissemination and oropharyngeal colonization of the offending organisms should be emphasized.

Bacterial Infections↗

PubMedDate not supplied

Effect of low-dose prednisolone on sperm fertilizing capacity in subfertile men with circulating antisperm antibodies.

To assess if low-dose prednisolone reduced circulating antisperm antibodies and improved sperm fertilizing capacity, the hamster oocyte penetration test (HOPT) was used to evaluate treatment in 36 males with significant serum antisperm antibodies, measured by the tray agglutination test (TAT). Prednisolone 5 mg three times a day for 3 months was used. Only couples in whom all tests in the female partner were normal were entered into the study. A significant increase in sperm density, normal morphology, and HOPT were noted after therapy (p < .001). A significant decrease in antisperm antibody titer was noted (p < .0001) and correlated with improvement of HOPT (p < .05). There were no significant side effects. Six pregnancies (17%) occurred. Three pregnancies (18%) occurred in partners of an untreated group of 17 men. Prednisolone therapy in this regime does not significantly improve pregnancy rates. The HOPT does not offer any additional information for predicting patients who will show an improvement in antibody titers or achieve pregnancy after steroids.

Adult↗