2003 OPEN FORUM Abstracts
Are Emergency Medical Technicians Predisposed To Administer Pejorative Ventilatory Strategies To Patients Intubated For Acute Severe Asthma?
Jeffrey M. Haynes RRT RPFT St. Joseph Hospital, Nashua,
New Hampshire.
Background: Positive pressure ventilatory strategies that incorporate
large tidal volumes (Vt), rapid respiratory rates (RR), and long inspiratory
time (Ti) are known to cause pulmonary volutrauma and hemodynamic depression
due to dynamic hyperinflation in patients with obstructive airways disease.1 Since
a fatal or near fatal asthma attack can occur unexpectedly and with a short
duration of increased symptoms,2 emergency medical technicians (EMT)
might be the first clinicians to care for the critically-ill asthmatic. Moreover,
most patients who have fatal asthma attacks die before reaching the hospital.2 Therefore,
this study sought to determine whether EMTs are predisposed to administer pejorative
ventilatory strategies while using a bag-valve ventilator to ventilate patients
intubated for acute severe asthma without cardiac arrest.
Methods: An anonymous, convenience sample survey was given to 62 EMTs which included a clinical scenario question which was the focus of this study. Most of the surveys were taken in the presence of the author. The respondents were asked to choose one of three ventilatory strategies for an adult patient with a pulse who was being ventilated with a bag-valve ventilator following intubation for acute severe asthma. The ventilatory strategy choices were: (a) large Vt/high RR; (b) small-moderate Vt/lower RR; (c) long Ti/high RR.
RESULTS: 59 of the 62 surveys were included in the study; 1 survey was not returned and 2 were discarded because they were not filled out properly. Only 13 (22%) chose the small-moderate Vt/lower RR strategy. 8
(13%) chose the large Vt/high RR strategy, and 38 (64.4%) chose the long Ti/high
RR strategy.
Conclusions: Many EMTs appear predisposed to manually ventilate patients intubated for acute severe asthma with ventilatory strategies that would likely result in severe iatrogenic dynamic hyperinflation. Greater awareness of the potential hazards of using such ventilatory strategies for patients with obstructive airways disease is needed.
References
1. Tuxen DV. Detrimental effects of positive end-expiratory
pressure during controlled mechanical ventilation of patients with severe airflow
obstruction. Am Rev Respir Dis 1989:140:5-9.
2. Hannaway PJ. Demographic
characteristics of patients experiencing near-fatal and fatal asthma: results
of a regional survey of 400 asthma specialists.
Ann Allergy Asthma Immunol 2000;84:587-593.