  Effects of high-frequency jet ventilation on arterial baroreflex regulation of heart rate.; ; Brichant, Jean-François  et alin Journal of Applied Physiology (Bethesda, Md. : 1985) (1987), 63(6), 2216-22 Fifteen anesthetized mechanically ventilated patients recovering from multiple trauma were studied to compare the effects of high-frequency jet ventilation (HFJV) and continuous positive-pressure ... [more ▼] Fifteen anesthetized mechanically ventilated patients recovering from multiple trauma were studied to compare the effects of high-frequency jet ventilation (HFJV) and continuous positive-pressure ventilation (CPPV) on arterial baroreflex regulation of heart rate. Systolic arterial pressure and right atrial pressure were measured using indwelling catheters. Electrocardiogram (ECG) and mean airway pressure were continuously monitored. Lung volumes were measured using two linear differential transformers mounted on thoracic and abdominal belts. Baroreflex testing was performed by sequential intravenous bolus injections of phenylephrine (200 micrograms) and nitroglycerin (200 micrograms) to raise or lower systolic arterial pressure by 20-30 Torr. Baroreflex regulation of heart rate was expressed as the slope of the regression line between R-R interval of the ECG and systolic arterial pressure. In each mode of ventilation the ventilatory settings were chosen to control mean airway pressure and arterial PCO2 (PaCO2). In HFJV a tidal volume of 159 +/- 61 ml was administered at a frequency of 320 +/- 104 breaths/min, whereas in CPPV a tidal volume of 702 +/- 201 ml was administered at a frequency of 13 +/- 2 breaths/min. Control values of systolic arterial pressure, R-R interval, mean pulmonary volume above apneic functional residual capacity, end-expiratory pulmonary volume, right atrial pressure, mean airway pressure, PaCO2, pH, PaO2, and temperature before injection of phenylephrine or nitroglycerin were comparable in HFJV and CPPV. Baroreflex regulation of heart rate after nitroglycerin injection was significantly higher in HFJV (4.1 +/- 2.8 ms/Torr) than in CPPV (1.96 +/- 1.23 ms/Torr).(ABSTRACT TRUNCATED AT 250 WORDS) [less ▲] Detailed reference viewed: 24 (0 ULg)Intermittent positive pressure ventilation with either positive end-expiratory pressure or high frequency jet ventilation (HFJV), or HFJV alone in human acute respiratory failure.Brichant, Jean-François ; ; in Anesthesia and Analgesia (1986), 65(11), 1135-42 Continuous Positive Pressure Ventilation (CPPV), High-Frequency Jet Ventilation (HFJV), and a combination of HFJV with Intermittent Positive Pressure Ventilation (CV) were randomly compared in 13 ... [more ▼] Continuous Positive Pressure Ventilation (CPPV), High-Frequency Jet Ventilation (HFJV), and a combination of HFJV with Intermittent Positive Pressure Ventilation (CV) were randomly compared in 13 critically ill patients with severe acute respiratory failure. Ventilatory settings were chosen in order to apply the same mean airway pressure (Paw) during the three modes. Respiratory frequencies were adjusted during CPPV (16 +/- 2 breaths/min) and HFJV (235 +/- 32 breaths/min) to achieve the same level of PaCO2 and were then combined during CV. All patients were heavily sedated during the study and had had peripheral and balloon-tipped pulmonary arterial catheters previously inserted. After a steady state at FIO2 1 in each mode of ventilation, hemodynamic and respiratory parameters were measured. A Paw of 13.8 +/- 2.9 mm Hg was applied to each patient by using a PEEP of 7.4 mm Hg during CPPV; a driving pressure of 2.9 +/- 0.2 bars and an I/E ratio of 0.43 during HFJV; and by combining HFJV, using a driving pressure of 1.2 +/- 0.3 bars with intermittent positive pressure ventilation during CV. There were no significant differences in any of the hemodynamic or respiratory parameters measured, except for a significant decrease in PaCO2 during CV when compared to CPPV or HFJV. We concluded that 1) arterial oxygenation and cardiac output depend mainly on Paw independent of the method used to increase Paw and 2) CV can improve CO2 elimination without increasing Paw.(ABSTRACT TRUNCATED AT 250 WORDS) [less ▲] Detailed reference viewed: 20 (0 ULg) |
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