Study protocol for a single-centre randomised controlled trial to investigate the effect of lung recruitment in paediatric patients after cardiac surgery

Abstract

Introduction: A number of published studies have revealed that lung recruitment can improve oxygenation, shorten the duration of mechanical ventilation (MV) and decrease mortality in adults with acute hypoxaemic respiratory failure, especially patients with acute respiratory distress syndrome. However, few articles have assessed lung recruitment in paediatric patients, especially after cardiac surgery. This clinical trial aimed to determine whether lung recruitment can reduce the duration of MV in paediatric patients with hypoxaemic respiratory failure after cardiac surgery.

Method and analysis: In this trial, we will randomly assign 234 paediatric patients (aged 28 days to 14 years) within 72 hours after cardiac surgery with an arterial oxygen tension (PaO₂) to fraction of inspired oxygen (FiO₂) ratio (PaO₂/FiO₂) of <300 to either a lung recruitment group or a conventional group. The primary endpoint will be the duration of MV. The secondary endpoints will be ventilator-free days, PaO₂/FiO₂, respiratory system compliance, duration of non-invasive ventilation, reintubation rate, length of intensive care unit stay, length of hospital stay, occurrence of serious adverse events (barotrauma, persistent hypotension and arrhythmia), postoperative pulmonary complications.

Ethics and dissemination: The ethics committee of West China Hospital of Sichuan University granted ethics approval for this study (20 August 2019). The results will be published in peer-reviewed journals and presented at conferences.

Trial registration number: ChiCTR1900025990.

Keywords: Cardiac surgery; Paediatric cardiac surgery; Paediatric intensive & critical care; Protocols & guidelines.

Figure 1

Enrolment and study protocol. FiO₂, fraction of inspired oxygen; PEEP, positive end-expiratory pressure; RM, recruitment manoeuvre; SBT, Spontaneous Breathing Trials; NIV, non-invasive ventilation.

Figure 2

Recruitment manoeuvre (RM) procedure. The RM will be performed in synchronised intermittent mandatory ventilation-pressure control mode with a fixed driving pressure of 15 cm H₂O above positive end-expiratory pressure (PEEP). PEEP will be increased by 5 cm H₂O every 2 min to a maximum of 20 cm H₂O. During the decremental phase of the RM, PEEP will be optimised to achieve better dynamic compliance (Cdyn; decremental PEEP trial). The PEEP with the best Cdyn is called the closing pressure. After the decremental PEEP trial, the RM will be repeated with a PEEP of 20 cm H₂O and a DP of 15 cm H₂O. The optimal PEEP will be the closing pressure plus. 2 cm H₂O. For example, figure 2 shows that the PEEP with the best Cdyn is 9 cm H₂O. Thus, PEEP will be set to 11 cm H₂O.