Biomedical subjects

J F Cosgrove

Publications and source records attributed to J F Cosgrove.

22 records · Page 2Linked to original sources

PubMed1976

Components of respiratory depression after narcotic premedication in adolescents.

The effects of narcotics on ventilatory control were assessed in 13 adolescents and young adults. Both a narcotic and narcotic-phenothiazine significantly depressed the CO2 response curve. Using an occlusion pressure technique (Pm100) to evaluate those neuromuscular processes that generate forces acting on the ventilatory pump, it was found that narcotic agents reduced neuromuscular drive. In most subjects, narcotics had an additional action that contributed to the overall ventilatory depression. Using carbon dioxide to vary neuromuscular drive before and after drug administration at constant levels of neuromuscular drive the drugs reduced tidal-volume responsiveness of the pump. We conclude that narcotics impair ventilation through a combination of two effects; first, reduced neuromuscular drive, most probably due to central depression, and second, increased impedance of the ventilatory pump, most probably due to a decrease in chest-wall compliance.

Adolescent↗

PubMed1976

The ventilatory response to carbon dioxide in asthmatic children, measured by the mouth-occlusion method (Pm100).

Ventilatory responses to carbon dioxide vary widely in patients with bronchial asthma; some have a high response despite increased airway resistance. This paradoxical response was studied in 31 asthmatic children and 22 age-matched healthy children. Measurement of the ventilatory response to carbon dioxide with a conventional rebreathing method showed wide variation in the patients, paralleling the degree of their airway obstruction as measured by the one-second forced expiratory volume and maximal midexpiratory flow rate, but their mean response was similar to that in the control subjects. The ventilatory response was then determined with a new index (Pm100), which rises linearly with increasing carbon dioxide concentration. Despite wide variation in the slope of Pm100 in the patients, their mean response significantly exceeded normal, confirming that the neurochemical drive is increased in bronchial asthma.

Adolescent↗

PubMed1975

A new method of evaluating the chemosensitivity of the respiratory center in children.

Decreased ventilatory response to carbon dioxide is often present in lung disease. This can be due to a reduction in the output of the respiratory center or an inability of the respiratory pump to respond to a normal output because of the size or impedence of the pump. To separate these mechanisms we have measured the isometric force developed by the respiratory muscle during brief airway occlusion, by measuring the pressure generated at 100 msec (Pm100). We studied 43 subjects ranging in age from 6 to 50 years, and nine neonates. We found a linear rise of Pm100 with rising PAco2 during carbon dioxide rebreathing maneuvers. Our results also show that although there are wide variations in slopes of Pm100 to carbon dioxide tension (SPm100/PAco2) between individuals, in a given subject this slope remains constant even following repeated studies. It also remains constant for age and size, indicating that the neuromechanical output of the respiratory apparatus does not change with growth. In contrast the ventilatory response either assessed as Ve/PAco2 or Vt/PAco2 depended on age and lung size. The results suggest that throughout growth, comparison of Pm100/PAco2 and Ve/PAco2 can distinguish between abnormalities of neuromuscular output from other causes of ventilatory impairment.

Adolescent↗

PubMedDate not supplied

Inadequate assessment of the airway and ventilation in acute poisoning. A need for improved education?

AIMS AND OBJECTIVES: To analyse the initial management of acute poisoning patients, and whether respiratory morbidity was related to inadequate assessment of airway and ventilation. METHODS: A retrospective analysis of the assessment and resuscitation of a group of acute poisoning patients, as documented in the clinical records. SUBJECTS AND SETTING: Forty one patients admitted to either Intensive Care or Coronary Care Units in a UK teaching hospital with a diagnosis of acute poisoning, between 12 January 1997 and 21 January 1998. STANDARDS: Advanced Life Support Guidelines were used to compare initial assessment. Criteria for intubation and ventilation described by Gentleman was used as the standard for intubation. RESULTS: Thirty seven patients had documented Glasgow Coma Scales at the time of admission, 27 were managed appropriately; one exhibited signs of aspiration. Ten patients were judged to be managed inappropriately; six exhibited clinical signs of aspiration. Four patients had unidentified Glasgow Coma Scales. CONCLUSIONS: Increased emphasis on 'Airway and Breathing' remains necessary in medical education. Regional recommendations for the management of acute poisoning require 'intubation guidelines'. Appropriate ward settings for monitoring such patients may pre-empt the onset of major respiratory problems.

Acute Disease↗