High-frequency Percussive Ventilation Research Articles

The usefulness of combined high-frequency percussive ventilation during acute respiratory failure after smoke inhalation

Inhalation injury and bacterial pneumonia represent some of the most important causes of mortality in burn patients. We describe 11 severely burned patients with acute respiratory failure due to inhalation injury who did not respond adequately to conventional respiratory support. High-frequency percussive ventilation (HFPV) is a recent ventilatory mode, which combines the advantages of conventional ventilation with some of those of high-frequency ventilation. Seven patients developed pulmonary infection during the acute phase; one patient died of multiple organ failure on day 25. All the other patients survived; two developed bronchiolitis obliterans symptoms before discharge. No side-effects were noted and haemodynamic tolerance of HFPV was excellent. Our findings suggest that HFPV can improve pulmonary function and gas exchange in these catastrophic pulmonary failures following inhalation injury.

Burn pain relief

To evaluate changes in respiratory and hemodynamic function of patients with ARDS and requiring high-frequency percussive ventilation (HFPV) after failure of conventional ventilation (CV).Retrospective case series.Surgical ICU (SICU) and medical ICU (MICU) of an academic county facility.Thirty-two consecutive patients with ARDS (20 from SICU, 12 from MICU) who were unresponsive to at least 48 h of CV and were switched to HFPV were studied. Data on respiratory and hemodynamic parameters were collected during the 48 h preceding and the 48 h after institution of HFPV and compared. Between the period of CV and the period of HFPV, the ratio of Pao2 to the fraction of inspired oxygen (Fio2) increased ([mean ± SE] 130 ± 8 vs 172 ± 17; p = 0.027), peak inspiratory pressure (PIP) decreased (39.5 ± 1.7 vs 32.5 ± 1.9 mm Hg; p = 0.002), and mean airway pressure (MAP) increased (19.2 ± 1.2 vs 27.5 ± 1.4 mm Hg; p < 0.001). The rate of change of Pao2/Fio2 per hour was also significantly improved between the two periods. The same changes in Pao2/Fio2, PIP, and MAP were observed when the last value recorded while the patients were on CV was compared with the first value recorded after 1 h of HFPV. This improvement was sustained but not amplified during the hours of HFPV. The patterns of improvement in these three parameters were similar in SICU and MICU patients as well as in volume-control and pressure-control patients. There were no changes in hemodynamic parameters.The HFPV improves oxygenation by increasing MAP and decreasing PIP. This improvement is achieved soon after institution of HFPV and is maintained without affecting hemodynamics.

Prophylactic Use of High-frequency Percussive Ventilation in Patients with Inhalation Injury

Death and the incidence of pneumonia are significantly increased in burn patients with inhalation injury, despite application of conventional ventilatory support techniques. The effect of high-frequency percussive ventilation on mortality rate, incidence of pulmonary infection, and barotrauma were studied in 54 burn patients with documented inhalation injury admitted between March 1987 and September 1990 as compared to an historic cohort treated between 1980 and 1984. All patients satisfied clinical criteria for mechanical ventilation. High-frequency percussive ventilation was initiated within 24 hours of intubation. The patients' mean age and burn size were 32.2 years and 47.8%, respectively (ranges, 15 to 88 years; 0% to 90%). The mean number of ventilator days was 15.3 +/- 16.7 (range, 1 to 150 days), with 26% of patients ventilated for more than 2 weeks. Fourteen patients (25.9%) developed pneumonia compared to an historic frequency of 45.8% (p less than 0.005). Mortality rate was 18.5% (10 patients) with an expected historic number of deaths of 23 (95% confidence limits of 17 to 28 deaths). The documented improvement in survival rate and decrease in the incidence of pneumonia in patients treated with prophylactic high-frequency ventilation (HFV), as compared to a cohort of patients treated in the 7 years before the trial, indicates the importance of small airway patency in the pathogenesis of inhalation injury sequelae and supports further use and evaluation of HFV.

High-frequency percussive ventilation compared with conventional mechanical ventilation

In seven patients with severe respiratory distress, conventional mechanical ventilation and PEEP were used initially for respiratory support, which was changed to high-frequency percussive ventilation (HFPV) at the same level of airway pressure and FIO2. During both modes of ventilation, patients could breathe spontaneously via a low-threshold demand valve. With HFPV, PaO2 improved significantly (p less than .01) compared with PaO2 during conventional methods. Cardiac output was unaffected by the change to HFPV.

High-frequency percussive ventilation in patients with inhalation injury.

Inhalation injury complicated by bacterial pneumonia is now one of the primary causes of morbidity and mortality in patients with thermal injury. We have investigated the use of high-frequency percussive ventilation (HFPV) as a means of ventilatory support for these patients. We propose that high-frequency ventilation may decrease the incidence of pulmonary infection following inhalation injury and decrease the incidence of iatrogenic barotrauma caused by conventional ventilation. High-frequency ventilation was instituted initially as salvage therapy in a group of five patients. In each case, normocapnia or arterial pO2 saturation of greater than 90% on a FIO2 of 60% or less was achieved with high-frequency ventilation but not with conventional ventilation. A second group of ten patients was prospectively entered into a study on the use of HFPV in patients with inhalation injury. One patient was removed from the study, and one patient was unable to be ventilated because of severely noncompliant lungs. Eight patients with a mean age of 29 years and a mean burn size of 38% of the total body surface completed the protocol. All patients survived, two developed pneumonia, and one developed subcutaneous emphysema. These results suggest that HFPV is effective in the treatment of patients with severe inhalation injury.

High-frequency Percussive Ventilation in the Management of Elevated Intracranial Pressure

We evaluated 38 patients with combined head injury and respiratory failure requiring manipulation of mean airway pressure in order to achieve satisfactory oxygenation. All patients were initially maintained on conventional ventilatory support. When entry criteria were met, patients were transitioned to high-frequency percussive ventilation (HFPV) and cardiorespiratory variables were measured. HFPV resulted in a statistically significant decrease in intracranial pressures in patients when ICP remained greater than 15 mm Hg in spite of optimum medical management. Satisfactory oxygenation was obtained at approximately half the level of CPAP and peak inspiratory pressure as that on conventional ventilation. Thus HFPV provides an acceptable alternative method of ventilatory support in patients with combined head injury and respiratory failure.