Pathophysiological Impact of Delayed Sternal Closure on the Respiratory System and Hemodynamics in Pediatric Cardiac Surgery Patients

Abstract

Background:

Delayed sternal closure is often necessary in pediatric cardiac surgery; however, its impact on the respiratory system and hemodynamics remains unclear. To our knowledge no prior studies have assessed intrapleural pressure (P_pl) changes after delayed sternal closure using esophageal pressure (P_es) measurements. This study aimed to investigate the respiratory system and hemodynamic changes associated with delayed sternal closure in pediatric patients using P_es measurement.

Methods:

This retrospective observational study included subjects <2 years who underwent delayed sternal closure in a pediatric intensive care unit between January and November 2024. Respiratory and hemodynamic parameters were measured at 3 time points: before delayed sternal closure, immediately after delayed sternal closure, and 3 h post delayed sternal closure. P_es was used to estimate P_pl. Lung compliance (C_L), chest wall compliance (C_CW), respiratory system compliance (C_RS), and end-expiratory transpulmonary pressure were calculated. Hemodynamic data included heart rate (HR), vasoactive-inotropic score (VIS), and surrogate indicators of cardiac output.

Results:

Eight subjects were analyzed. End-expiratory P_es significantly increased after delayed sternal closure (before: 6.0 [4.8–7.0] cm H₂O; immediately after: 7.3 [5.8–9.3] cm H₂O; 3 h post delayed sternal closure: 8.1 [6.8–10.1] cm H₂O; P = .044), indicating elevated P_pl. C_L was numerically lower 3 h post delayed sternal closure (before: 0.72 [0.70–0.80] mL/cm H₂O/kg; immediately after: 0.73 [0.65–0.80] mL/cm H₂O/kg; 3 h post delayed sternal closure: 0.62 [0.56–0.74] mL/cm H₂O/kg; P = .09). HR (before: 150 [138–157] beats/min; immediately after: 165 [148–167] beats/min; 3 h post delayed sternal closure: 151 [149–163] beats/min; P = .02) and VIS (before: 12.8 [9.8–14.3]; immediately after: 14.3 [12.1–15.8]; 3 h post delayed sternal closure: 14.8 [12.1–15.8]; P = .003) significantly increased post delayed sternal closure.

Conclusions:

Delayed sternal closure increased P_pl by ∼2 cm H₂O, which may reduce lung compliance without affecting chest wall compliance and contribute to hemodynamic stress. These changes may necessitate optimized respiratory and circulatory support during and after delayed sternal closure.