Hemodynamic effects of high-frequency jet ventilation in patients with and without circulatory shock

Nineteen critically ill patients with acute respiratory failure were studied to compare the hemodynamic effects of continuous positive-pressure ventilation (CPPV) and high-frequency jet ventilation (HFJV) at comparable levels of alveolar ventilation. Patients were divided into three groups: Group 1 included seven patients without circulatory shock in whom mean airway pressure (Paw) was slightly higher during CPPV than during HFJV (17.3 +/- 3.0 vs. 13.0 +/- 2.9 mmHg); Group 2 included six patients without circulatory shock in whom HFJV and CPPV were compared at the same level of Paw (19.2 +/- 5.0 mmHg); Group 3 included seven patients with circulatory shock in whom HFJV and CPPV were compared at the same level of Paw (16.0 +/- 3.9 mmHg). The following respiratory frequencies were used in HFJV: Group 1, 200 +/- 76 beats/min; Group 2, 238 +/- 103 beats/min; Group 3, 286 +/- 149 beats/min. In all patients comparable levels of PaCO2 were obtained with CPPV and HFJV. In Group 1 patients, mean arterial pressure, cardiac index, and stroke index were significantly higher during HFJV. In Group 2 patients, no significant difference was found between HFJV and CPPV. In Group 3 patients, the following hemodynamic variables were significantly higher during HFJV: mean arterial pressure (71 +/- 24 vs. 84 +/- 23 mmHg), cardiac index (3.6 +/- 1 vs. 4.1 +/- 1.41 X min-1 X m-2), and oxygen delivery (403 +/- 93 vs. 471 +/- 124 ml X min-1 X m-2).(ABSTRACT TRUNCATED AT 250 WORDS)