Outcome analysis of a conservative approach to diaphragmatic paralysis following congenital cardiac surgery in neonates and infants: a bicentric retrospective study

Abstract

Objectives: Diaphragmatic paralysis following congenital cardiac surgery is associated with significant morbidity and mortality. Spontaneous recovery of diaphragmatic function has been described, contrasting with centres providing early diaphragmatic plication. We aimed to describe the outcomes of a conservative approach, as well as to identify factors associated with a failure of the strategy.

Methods: This is a retrospective study of patients admitted after cardiac surgery and suffering unilateral diaphragmatic paralysis within 2 French Paediatric Cardiac Surgery Centers. The conservative approach, defined by the prolonged use of ventilation until successful weaning from respiratory support, was the primary strategy adopted in both centres. In case of unsuccessful evolution, a diaphragmatic plication was scheduled. Total ventilation time included invasive and non-invasive ventilation. Diaphragm asymmetry was defined by the number of posterior rib segments counted between the 2 hemi-diaphragms on the chest X-ray after cardiac surgery.

Results: Fifty-one neonates and infants were included in the analysis. Patients' median age was 12.0 days at cardiac surgery (5.0-82.0), and median weight was 3.5 kg (2.8-4.9). The conservative approach was successful for 32/51 patients (63%), whereas 19/51 patients (37%) needed diaphragm plication. There was no difference in patients' characteristics between groups. Respiratory support prolonged for 21 days or more and diaphragm asymmetry more than 2 rib segments were independently associated with the failure of the conservative strategy [odds ratio (OR) 6.9 (1.29-37.3); P = 0.024 and OR 6.0 (1.4-24.7); P = 0.013, respectively].

Conclusions: The conservative approach was successful for 63% of the patients. We identified risk factors associated with the strategy's failure.

Keywords: Congenital heart surgery; Diaphragmatic plication; Paediatric intensive care; Phrenic nerve injury.

Figure 1:

Evaluation of diaphragm asymmetry. Postoperative chest X-ray in a 12-day-old neonate with unilateral left diaphragmatic paralysis. (A) At admission, the patient is intubated. (B) At postoperative day 3, diaphragmatic paralysis is suspected on chest X-ray and paradoxical movements of the diaphragm are recorded with ultrasounds. The patient receives non-invasive ventilation. (C) At day 10, the patient is not improving and diaphragm asymmetry is >2 posterior rib segments. (D) Result of diaphragmatic plication at day 16.

Figure 2:

Flow chart. DP: diaphragmatic paralysis; ICU: intensive care unit.

Figure 3:

Cumulative risk of unsuccessfulness of a conservative strategy depending on LOS in ICU displayed for all patients (A), and according to the diaphragm asymmetry (B): 1–2 rib segments (solid line) and >2 rib segments (dotted line). A Kaplan–Meier surviving analysis was conducted to display the conservative approach’s cumulative failure rate over time, P < 0.05. ICU: intensive care unit; LOS: length of stay.