High-Frequency Percussive Ventilation Rescue Therapy in Morbidly Obese Patients Failing Conventional Mechanical Ventilation.

BACKGROUND: Morbidly obese patients with respiratory failure who do not improve on conventional mechanical ventilation (CMV) often undergo rescue therapy with extracorporeal membrane oxygenation (ECMO). We describe our experience with high-frequency percussive ventilation (HFPV) as a rescue modality. METHODS: In a retrospective analysis from 2009 to 2016, 12 morbidly obese patients underwent HFPV after failing to wean from CMV. Data were collected regarding demographics, cause of respiratory failure, ventilation settings, and hospital course outcomes. Our end point data were pre- and post-HFPV partial pressure of arterial oxygen and PaO2 to fraction of inspired oxygen (PF) ratios measured at initiation, 2, and 24 hours. RESULTS: Twelve morbidly obese patients required HFPV for respiratory failure. Causes of respiratory failure overlapped and included cardiogenic pulmonary edema (n = 8), pneumonia (n = 5), septic shock (n = 5), and asthma (n = 1). After HFPV initiation, mean fraction of inspired oxygen FiO2 was tapered from 98% to 82% and 66% at 2 and 24 hours, respectively. Mean PaO2 increased from 60.9 mm Hg before HFPV to 175.1 mm Hg (P < .05) at initiation of HFPV, then sustained at 129.5 mm Hg (P < .05) and 88.1 mm Hg (P < .005) at 2 and 24 hours, respectively. Mean PF ratio improved from 66.1 before HFPV to 180.3 (P < .05), 181.0 (P < .05) and 148.9 (P < .0005) at initiation, 2, and 24 hours, respectively. The improvement in mean PaO2 and PF ratios was durable at 24 hours whether or not the patient was returned to CMV (n = 10) or remained on HFPV (n = 2). Survival to discharge was 66.7%. CONCLUSION: In our cohort of morbidly obese patients, HFPV was successfully utilized as a rescue therapy precluding the need for ECMO. Despite our small sample size, HFPV should be considered as a rescue therapy in morbidly obese patients failing CMV prior to the initiation of ECMO. Our retrospective analysis supports consideration for HFPV as another form of rescue therapy for obese patients with refractory hypoxemia and respiratory failure who are not improving with CMV.

Use of High-Frequency Percussive Ventilation to Expand Organ Donor Pool.

A 34-year-old woman was brought in to the emergency department after a motor vehicle accident. She had signs of traumatic head injury with Glasgow Coma Scale score of 3, and her neurological examination was consistent with brain death. She was persistently hypoxic on conventional mechanical ventilation and high-frequency percussive ventilation was initiated. The patient's oxygenation improved and was sustained long enough to provide time for organ procurement. This is the first case portraying high-frequency percussive ventilation as a bridge for donors failing on conventional mechanical ventilation.

High-Frequency Percussive Ventilation Facilitates Weaning from Extracorporeal Membrane Oxygenation in Adults.

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is an invaluable rescue therapy for patients suffering from cardiopulmonary arrest, but it is not without its drawbacks. There are cases where patients recover their cardiac function, yet they fail to wean to mechanical conventional ventilation (MCV). The use of high-frequency percussive ventilation (HFPV) has been described in patients with acute respiratory failure (RF) who fail MCV. We describe our experience with five patients who underwent VA-ECMO for cardiopulmonary arrest who were successfully weaned from VA-ECMO with HFPV after failure to wean with MCV. Weaning trials of HFPV a day before decannulation or at the time of separation from VA-ECMO were conducted. Primary endpoint data collected include pre- and post-HFPV partial pressures of oxygen (PaO2) and PaO2/FIO2 (P/F) ratios measured at 2 and 24 hours after institution of HFPV. Additional periprocedural data points were collected including length of time on ECMO, hospital stay, and survival to discharge. Four of five patients were placed on VA-ECMO subsequent to percutaneous coronary intervention. One patient had cardiac arrest secondary to RF. Mean PaO2 (44 ± 15.9 mmHg vs. 354 ± 149 mmHg, p < .01) and mean P/F ratio (44 ± 15.9 vs. 354 ± 149, p < .01) increased dramatically at 2 hours after the initiation of HFPV. The improvement in mean PaO2 and P/F ratio was durable at 24 hours whether or not the patient was returned to MCV (n = 3) or remained on HFPV (n = 2) (44 ± 15.9 mmHg vs. 131 ± 68.7 mmHg, p = .036 and 44 ± 15.9 vs. 169 ± 69.9, p < .01, respectively). Survival to discharge was 80%. The data presented suggest that HFPV may be used as a strategy to shorten time on ECMO, thereby reducing the negative effects of the ECMO circuit and improving its cost efficacy.

The use of high-frequency percussive ventilation after cardiac surgery significantly improves gas exchange without impairment of hemodynamics.

OBJECTIVE: Respiratory failure represents a significant source of morbidity and mortality for surgical patients. High-frequency percussive ventilation (HFPV) is emerging as a potentially effective rescue therapy in patients failing conventional mechanical ventilation (CMV). Use of HFPV is often limited by concerns for potential effects on hemodynamics, which is particularly tenuous in patients immediately after cardiac surgery. In this manuscript we evaluated the effects of HFPV on gas exchange and cardiac hemodynamics in the immediate postoperative period after cardiac surgery, in comparison with CMV. METHODS: Twenty-four consecutive cardiac surgery patients were ventilated in immediate postoperative period with HFPV for two to four hours, then they switched to a CMV using the adaptive support ventilation mode for weaning. Arterial blood gases were performed during the first and second hour on HFPV, and at 45 minutes after initiation of CMV. Respiratory settings and invasive hemodynamic data (mixed venous oxygen saturation, central venous pressure, systemic and pulmonary blood pressure, cardiac output and index) were collected utilizing right heart pulmonary catheter and arterial lines during HFPV and CMV. Primary outcome was improvement in the ratio between partial pressure of oxygen to fraction of inspired oxygen (P/F ratio) and changes in hemodynamics. RESULTS: Analysis of data for 24 patients revealed a significantly better P/F ratio during the first and second hour on HFPV, compared with a P/F ratio on CMV (420.0 ± 158.8, 459.2 ± 138.5, and 260.2 ± 98.5 respectively, p < 0.05), suggesting much better gas exchange on HFPV than on CMV. Hemodynamics were not affected by the mode of the ventilation. CONCLUSIONS: Improvement in gas exchange, reflected in a significantly improved P/F ratio, wasn't accompanied by worsening in hemodynamic parameters. The significant gains in the P/F ratio were lost when patients were switched to conventional ventilation. This data suggest that HFPV provides significantly better gas exchange compared with CMV and can be safely utilized in postoperative cardiac patients without any significant effect on hemodynamics.

Venovenous extracorporeal membrane oxygenation for respiratory failure refractory to high frequency percussive ventilation.

BACKGROUND: High frequency percussive ventilation (HFPV) has demonstrated improvements in gas exchange, but not in clinical outcomes. OBJECTIVES: We utilize HFPV in patients failing conventional ventilation (CV), with rescue venovenous extracorporeal membrane oxygenation (VV ECMO) reserved for failure of HFPV, and we describe our experience with such a strategy. METHODS: All adult patients (age >18 years) placed on HFPV for failure of CV at a single institution over a 10-year period were included. Those maintained on HFPV were compared to those that failed HFPV and required VV ECMO. Survival was compared to expected survival after upfront VV ECMO as estimated by VV ECMO risk prediction models. RESULTS: Sixty-four patients were placed on HFPV for failure of CV over a 10-year period. After HFPV initiation, the P/F ratio rose from 76mmHg to 153.3mmHg in the 69 % of patients successfully maintained on HFPV. The P/F ratio only rose from 60.3mmHg to 67mmHg in the other 31 % of patients, and they underwent rescue ECMO with the P/F ratio rising to 261.6mmHg. The P/F ratio continued to improve in HFPV patients, while it declined in ECMO patients, such that at 24 h, the P/F ratio was greater in HFPV patients. The strongest independent predictor of failure of HFPV requiring rescue VV ECMO was a lower pO2 (p = .055). Overall in-hospital survival (59.4 %) was similar to that expected with upfront ECMO (RESP score: 57 %). CONCLUSIONS: HFPV demonstrated significant and sustained improvements in gas exchange and may obviate the need for ECMO and its associated complications.

The Use of High-Frequency Percussive Ventilation for Whole-Lung Lavage: A Case Report.

Whole-lung lavage (WLL) remains the gold standard in the treatment of pulmonary alveolar proteinosis. However, anesthetic management during WLL can be challenging because of the risk of intraoperative hypoxemia and various cardiorespiratory complications of 1-lung ventilation. Here, we describe a novel strategy involving the application of high-frequency percussive ventilation using a volumetric diffusive respirator (VDR-4) during WLL in a 47-year-old woman with pulmonary alveolar proteinosis. Our observations suggest that high-frequency percussive ventilation is a potentially effective ventilation strategy during WLL that may reduce the risk of hypoxemia and facilitate lavage.

High-frequency percussive ventilation in cardiac surgery patients failing mechanical conventional ventilation.

OBJECTIVES: Failure of mechanical conventional ventilation (MCV) after cardiac surgery portends a dismal prognosis, with extracorporeal membrane oxygenation frequently utilized as a salvage therapy. We describe our experience with high-frequency percussive ventilation (HFPV) as a rescue therapy for hypoxaemia refractory to MCV after cardiac surgery. METHODS: In a 6-year retrospective analysis from 2009 to 2015, we identified 16 subjects who required HFPV after cardiac surgery. Data regarding demographics, intraoperative details, postoperative ventilatory settings including length of time on HFPV and postoperative outcomes were collected. The primary outcome was improvement in oxygenation as measured by pre- and post-HFPV partial pressures of oxygen (pO2) and ratio of pO2 to fraction of inspired oxygen (P/F ratio). RESULTS: Sixteen patients required HFPV after cardiac surgery. Operative procedures included coronary artery bypass surgery (n = 6), aortic aneurysm or dissection repair (n = 5), valve with bypass surgery (n = 2), aortic valve replacement (n = 2) and extracorporeal membrane oxygenation (n = 1). Median pO2 increased from 61 to 149.5 mmHg (P < 0.001) and the median P/F ratio improved from 62 to 169 (P < 0.001). The improvement in pO2 and P/F ratio was durable at 24 h whether the patient was returned to MCV (n = 4) or remained on HFPV (n = 12) with pO2 and P/F ratio increasing from 61 to 104 mmHg (P < 0.001) and from 62 to 193.5 (P < 0.001), respectively. Survival to discharge was 81%. CONCLUSIONS: In our cohort of cardiac surgical patients, HFPV was successfully utilized as a rescue therapy, obviating the need for extracorporeal membrane oxygenation. Although further studies are warranted, HFPV should be considered in cardiac surgical patients failing MCV.

Update in Management of Severe Hypoxemic Respiratory Failure.

Mortality related to severe-moderate and severe ARDS remains high. We searched the literature to update this topic. We defined severe hypoxemic respiratory failure as Pao2/Fio2 < 150 mm Hg (ie, severe-moderate and severe ARDS). For these patients, we support setting the ventilator to a tidal volume of 4 to 8 mL/kg predicted body weight (PBW), with plateau pressure (Pplat) ≤ 30 cm H2O, and initial positive end-expiratory pressure (PEEP) of 10 to 12 cm H2O. To promote alveolar recruitment, we propose increasing PEEP in increments of 2 to 3 cm provided that Pplat remains ≤ 30 cm H2O and driving pressure does not increase. A fluid-restricted strategy is recommended, and nonrespiratory causes of hypoxemia should be considered. For patients who remain hypoxemic after PEEP optimization, neuromuscular blockade and prone positioning should be considered. Profound refractory hypoxemia (Pao2/Fio2 < 80 mm Hg) after PEEP titration is an indication to consider extracorporeal life support. This may necessitate early transfer to a center with expertise in these techniques. Inhaled vasodilators and nontraditional ventilator modes may improve oxygenation, but evidence for improved outcomes is weak.