High-frequency oscillatory ventilation for acute respiratory distress syndrome

Abstract

In our study, HFOV was effective in oxygenation and seems to be safe for pediatric ARDS patients. HFOV affected ARDSp and ARDSexp paediatric patients differently. However prospective, randomized controlled trials are needed to identify its benefits over conventional modes of mechanical ventilation.

High-frequency oscillatory ventilation in a tertiary paediatric intensive care unit in an academic hospital in Johannesburg, South Africa

“…This proportion is in excess of reports from previous HFOV studies. [3,8,17,20,24] This appeared to be dose-dependent, as vasoactive usage was related to the magnitude of increase in Paw relative to cMAP, evidenced by the 80% of patients with an initial Paw increase of >6 cmH 2 0 who required new or increasing doses of vasoactives. A possible explanation for the difference in haemodynamic stability might be the recent trend toward more fluid-restrictive management of respiratory patients, which may have resulted in reduced preload in the face of increased intrathoracic pressure.…”

“…During the study period, a substantial proportion (32.7%) of patients with respiratory conditions were managed with HFOV, slightly higher than the reported use of HFOV globally, of between 3 and 30%. [2][3][4] The use of HFOV is usually in the setting of hypoxaemic respiratory failure necessitating ventilator settings in excess of accepted safe limits, or failure to achieve adequate gas exchange using CMV, particularly in units without access to extracorporeal respiratory support, as is the case in the study PICU. [1,8,10,11,17] While 25 (73.5%) of the patients included in the study did indeed meet unit criteria for transition to HFOV on the basis of oxygenation criteria (OI ≥12), somewhat surprisingly, nearly half (44.1%) of the indications for HFOV were refractory respiratory acidosis.…”

“…[4,10] Additionally, some recommendations suggest the use of HFOV for refractory respiratory acidosis using a PaCO 2 ≥80 mmHg or a pH ≤7.25 as trigger criteria. [2,3,16] The initial settings of the HFOV have, perhaps unsurprisingly, varied considerably between reports. Airway pressure (Paw) has been set at varying levels relative to the mean airway pressure produced by CMV (cMAP), with some suggesting setting Paw at the same level as cMAP, [2] while others suggest anywhere up to 8 cmH 2 0 above cMAP.…”

“…[10][11][12]17] Paw has then been titrated based on oxygenation and chest inflation on radiograph. [2][3][4]10,12,14,18,19] The initial frequency has been guided by the age and weight of the patient, with values ranging between 5 and 10 Hz for patients weighing ≥10 kg, and 10 and 15 Hz for patients weighing ˂10 kg. [2][3][4]8,10,11,17,18,20] Strategies to set amplitude have used 'chest wall wiggle' , with subsequent titration, together with frequency if required, to achieve a PaCO 2 target.…”

“…[2][3][4]10,12,14,18,19] The initial frequency has been guided by the age and weight of the patient, with values ranging between 5 and 10 Hz for patients weighing ≥10 kg, and 10 and 15 Hz for patients weighing ˂10 kg. [2][3][4]8,10,11,17,18,20] Strategies to set amplitude have used 'chest wall wiggle' , with subsequent titration, together with frequency if required, to achieve a PaCO 2 target. [2,[10][11][12]14,18] Reported triggers prompting transition back to CMV have also varied widely, with the use of objective criteria for Paw (10 -20 cmH 2 O) and FiO 2 (≤0.5), as well as the more subjective criterion of absence of significant desaturation with suctioning.…”