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

Abstract

Conventional mechanical ventilation (CMV) is sometimes unable to achieve adequate gas exchange, necessitating the use of nonconventional ventilatory strategies. The recent Pediatric Acute Lung Injury Consensus Conference (PALICC) recommended the use of high frequency oscillatory ventilation (HFOV) in severe paediatric acute respiratory distress syndrome (PARDS) as an alternative (or rescue) ventilatory mode. [1] Reported use of HFOV in critically ill children varies between 3% and 30%. [2-4] Despite the putative benefits of HFOV, randomised controlled trials in paediatrics demonstrating the superiority of HFOV over conventional modes are scarce, so the role of HFOV remains confined to use as salvage within recent paediatric mechanical ventilation guidelines. [1,5] HFOV has come under scrutiny with the recent publication of two large trials looking at HFOV in adults with moderate to severe acute respiratory distress syndrome. The lack of benefit found, as well as concerns regarding potential harm, have prompted deliberations around its continued use. [6,7] Practices around HFOV use vary, and may need to be refined. [4] HFOV has generally been considered a rescue strategy, and as such, the optimum timing of initiation is unclear. [8,9] The most commonly used triggers to transition from CMV to HFOV are both markers of oxygenation, namely the PaO 2 :FiO 2 (PF) ratio and the oxygenation index (OI); however, a wide range of values for both parameters has been reported. [10-14] Generally, HFOV is suggested when oxygenation remains severely impaired (SpO 2 <88% and/or PaO 2 <50 mmHg with a FiO 2 >0.6) despite maximal lung-protective CMV limiting peak pressures to less than 30-35 cmH20 with sufficient positive end-expiratory pressure

How do we use high-frequency oscillation: Primary ventilation, rescue therapy or switch directly to early extracorporeal membrane oxygenation?

“…Furthermore, Cawood et al [10] describe more air leaks (11.8%) than reported in the literature. Pressure-wave damping between the upper airways and alveoli depends on the homogeneity and pathophysiological process in the lung.…”

“…This degree of acidosis has deleterious immunological, vascular and cardiac effects. It is therefore appropriate to escalate treatment, and Cawood et al [10] confirm the efficacy of HFO to clear CO 2 .…”

“…In this issue, Cawood et al [10] describe a 2-year single-centre experience of rescue HFO in a South African (SA) PICU without ECMO availability. The study confirms improved oxygenation when using HFO, in agreement with international evidence.…”

Prevalence and Incidence of Pediatric Acute Respiratory Distress Syndrome in a Tertiary Academic PICU in South Africa

“…Although the prevalence of pARDS in South Africa is unknown, some studies suggest the burden of disease may be high in specific PICU populations (4, 5). This study aimed primarily to determine the prevalence of pARDS among infants and children admitted to the PICU at Red Cross War Memorial Children’s Hospital (RCWMCH), Cape Town, South Africa.…”