Hemodynamic and respiratory effects of transtracheal highfrequency jet ventilation during difficult intubation

Abstract

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 temporomandibularjoint 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 Ag/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 inspiratorylexpiratory ratio of 25%. Thoracic electrical bioimpedonce 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 < 0.05). MAP decreased significantly after 10 minutes of HFJV compared with the preinduction value (mean, 97 to 71 mmHg; p < 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 < 0.05). Arterial carbon dioxide tension also increased, from 39 to 42 mmHg ( p < 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.