Hemodynamic and respiratory effects of transtracheal high-frequency jet ventilation during difficult intubation.

STUDY OBJECTIVE

To evaluate the hemodynamic and respiratory effects of percutaneous transtracheal high-frequency jet ventilation (HFJV) during difficult intubation using fiberoptic bronchoscopy under general anesthesia.

DESIGN

Prospective study.

SETTING

Surgical patients scheduled for general anesthesia at the Medical College of Virginia Hospital.

PATIENTS

Eight patients with known difficult airways. Three patients had deformed facial structures. One patient had temporomandibular joint impairment. Four patients had tumors of the oral cavity with deformed upper airways.

INTERVENTIONS

A 13-gauge cricothyroidotomy jet ventilation cannula was inserted percutaneously under local anesthesia. Anesthesia was induced with etomidate 0.2 to 0.3 mg/kg, alfentanil 15 to 20 micrograms/kg, and vecuronium 0.1 mg/kg. HFJV was started with 100% oxygen at 30 to 35 pounds per square inch of driving pressure, 100 cycles per minute, and an inspiratory/expiratory ratio of 25%. Thoracic electrical bioimpedance was used to measure cardiac index (CI) and ejection fraction (EF).

MEASUREMENTS AND MAIN RESULTS

Mean arterial pressure (MAP), heart rate (HR), CI, and EF were measured before induction of anesthesia; after 1 minute of HFJV, 5 minutes of HFJV, and 10 minutes of HFJV; and during positive pressure ventilation following fiberoptic intubation. Arterial blood gas samples were obtained before induction of anesthesia and after 10 minutes of HFJV. HR decreased significantly after 5 minutes of HFJV, after 10 minutes of HFJV, and after intubation (p less than 0.05). MAP decreased significantly after 10 minutes of HFJV compared with the preinduction value (mean, 97 to 71 mmHg; p less than 0.01). Although EF increased significantly following intubation, from 46% to 59%, there were no significant changes in CI. Arterial oxygen tension increased from 85 to 240 mmHg (p less than 0.05). Arterial carbon dioxide tension also increased, from 39 to 42 mmHg (p less than 0.05).

CONCLUSIONS

Transtracheal HFJV under general anesthesia with etomidate, alfentanil, and vecuronium provided satisfactory hemodynamic conditions and pulmonary gas exchange. Percutaneous transtracheal HFJV can be used safely to manage patients with a difficult airway under general anesthesia using fiberoptic bronchoscopy.