Clinical Application of Continuous Flow Apneic Ventilation

Abstract

Continuous flow apneic ventilation (CFAV) was studied in five adult female patients. After induction of anesthesia with thiopental sodium (5 mg/kg) and fentanyl (5 micrograms/kg), and paralysis with pancuronium bromide (0.12 mg/kg), the patients were ventilated with oxygen at an FIO2 of 1.0 by face mask. Two polyethylene catheters (outside diameter [OD] 2.5 mm) were each inserted into the right and left mainstem bronchi. Each catheter had a curved tip measuring 2 cm in length. The angulation of the catheter tip from the axis was 20 degrees for the right side and 30 degrees for the left side. The endobronchial position was checked by fiberoptic bronchoscopy. Subsequently, tracheal intubation was performed using a 7.5 mm OD tracheal tube. CFAV was started when both catheters were connected to the gas delivery system. Humidified oxygen was delivered at total flows between 0.6 and 0.7 1/min. Arterial blood gases were analyzed every 5 min for 30 min. Monitoring included electrocardiogram, indirect blood pressure, heart rate, temperature, and peripheral nerve stimulation. Adequate oxygenation was maintained in all patients, 39.76 +/- 4.32 kPa (299 +/- 37 mmHg) at 30 min. There was a significant rise in Paco2 (P less than 0.05) at 30 min compared to the control, 4.92 +/- 0.25 kPa compared to 7.30 +/- 0.53 kPa (37.0 +/- 1.9 mmHg compared to 54.9 +/- 4.0 mmHg). There was a mean rise in Paco2 of 0.03 kPa/min (0.6 mmHg/min) compared to 0.5 kPa/min (3.8 mmHg/min) with apneic diffusion ventilation. In one patient there was no increase in Paco2 during the 30 min of CFAV.(ABSTRACT TRUNCATED AT 250 WORDS)

Constant Flow Ventilation in Anesthetized Patients

“…During apneic diffusion oxygenation (ADO), in which oxygen flow is delivered across the proximal opening of a patent airway, no CO, elimination occurs (5,6) and average Paco, steadily increases by about 3.8 mm Hg/min (7). In contrast, during the second 5-min period of CFV in our study, the increase in Paco, with time was only 1.8 ?…”

“…The study of Babinksi et al (7) suggests that CFV might be clinically applicable during thoracic surgery where organ movement associated with normal mechanical ventilation is undesirable. During 30 min of CFV in the Babinski et al study, oxygenation remained good and Pacoz rose moderately but still remained within the clinically useful range (54.9 ?…”

“…Therefore, for any given V, effected by CFV, we would predict a greater Paco, increase in our patients. In addition, in contrast to Babinski et al (7) who positioned the ventilating catheters loose in the mainstem bronchi, we mounted the ventilating tubes onto the sides of a modified endotracheal tube to fulfill patient safety criteria (see below). The resulting larger cross-sectional area of the distal end of our CFV-OTT (Fig.…”

“…In low compliance pulmonary disease, CFV should prevent the high inflationary airway pressures with consequent cardiovascular depression and pulmonary barotrauma that can occur during IPPV (3,4,8). Recently, Babinski et al (7) have reported limited success with CFV in anesthetized patients. They directed a total oxygen flow of 0.6-0.7 L-kg '.min ' through two smalI tubes placed into the mainstem bronchi with the aid of a flexible bronchoscope.…”

“…During bronchoscopy or during large airway and intrathoracic surgery, CFV should permit better surgical exposure and a motionless operating field (3,4,7). In low compliance pulmonary disease, CFV should prevent the high inflationary airway pressures with consequent cardiovascular depression and pulmonary barotrauma that can occur during IPPV (3,4,8).…”