S Swartzman | PubMed Health

PubMed1984

Percutaneous transtracheal jet ventilation for cardiopulmonary resuscitation: evaluation of a new jet ventilator.

This study compared percutaneous transtracheal jet ventilation (PTJV) at a frequency (f) of 20/min, with high-frequency positive-pressure ventilation (HFPPV) at f of 60/min, and endotracheal intubation and intermittent positive-pressure ventilation (ET IPPV) at f of 10/min in apneic dogs. Fifty-four emergency medicine trainees (EMTs) attempted PTJV via a 14-gauge Angiocath attached to a hand-held jet ventilator, f of 20/min, and ET IPPV using an Ambu bag, f of 10/min. Twenty-nine other EMTs attempted cricothyrotomy using a prototype nonkinkable catheter (Arrow) and a new jet ventilator, Bronchovent, f of 60/min, equipped with a pressure sensor which stops ventilation at pressures greater than 20 cm H2O. Adequate oxygenation was achieved by all 3 groups, but only the HFPPV group avoided respiratory alkalosis. There was a higher equipment failure rate (catheter kinking and dislodgment) in the PTJV group. In the HFPPV group, the Bronchovent's pressure-limiting sensor stopped ventilation when the catheter was kinked or out of position, reducing the extent of subcutaneous emphysema and barotrauma. With further catheter improvements, HFPPV Bronchovent may offer a safe and reliable method of ventilating patients during CPR in the field.

Alkalosis, Respiratory↗

PubMed1984

Continuous flow apneic ventilation.

A study was designed to evaluate the adequacy of gas exchange during continuous flow apneic ventilation (CFAV) in dogs. Seventeen dogs (average weight 22.9 kg) were divided into three experimental groups. Group I (n = 7) was anesthetized, paralyzed and ventilated with air using intermittent positive pressure ventilation (IPPV) through a tracheal tube. The tube was removed and each main stem bronchus was cannulated with a 2.5 mm i.d., 4 mm o.d. polyethylene catheter using a fiberoptic bronchoscope. The tracheal tube was replaced to hold the catheters in place. Heated, humidified air was continuously delivered equally to each catheter. Total flows ranged from 8 to 28 l/min (0.4-1.4 l X kg-1 X min-1). Airway pressure (Paw) in the trachea did not exceed 2 mmHg (0.27 kPa). Adequate gas exchange in terms of arterial oxygen and arterial carbon dioxide tension (Pao2 and Paco2) was found after 30 min at flows greater than 16 l X min-1. Group II (n = 7) was managed similarly to the first group, insufflating endobronchial air using the optimal flow of 1.0 l X kg-1 X min-1 obtained from Group I. CFAV continued for 5 h in all animals. Blood gas samples and measurements of systemic blood pressure, heart rate (HR), pulmonary artery blood pressure, pulmonary artery wedge pressure, cardiac output (Qt), and temperature were taken every 30 min. Group III (n = 3) was anesthetized similarly to the other groups. Pulmonary gas distribution was evaluated in relation to catheter placement using Xe133. Results showed significant differences between Pao2 values during CFAV and IPPV; however, all animals were adequately oxygenated.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗