Transient Pulmonary Atelectasis after Ketamine Sedation during Cardiac Catheterization in Spontaneously Breathing Children with Congenital Heart Disease

Background: Ketamine is applied widely for sedation during cardiac catheterization in spontaneously breathing children with congenital heart disease (CHD). However, a rare and unreported respiratory complication, transient and reversible atelectasis of lungs (TRAL), was identified. Purpose: The study was performed to investigate retrospectively the prevalence and clinical characteristics of TRAL after ketamine sedation in pediatric cardiac catheterization. Methods: Four thousand four hundred and seventy-four sick children were sedated with ketamine, and pediatric cardiac catheterization was carried out under spontaneous breathing. TRAL was detected in 33 children (17 M/16 F, age was 2.1±1.7 years) by retrospective analysis. The clinical and radiographic characteristics were recorded before, during and after TRAL. Results: In pediatric cardiac catheterization, the prevalence of TRAL was 0.74% after ketamine sedation. TRAL occurred in 23 children with cyanotic CHD, and 10 with acyanotic CHD. All TRALs had common clinical and radiographic features: the diffuse opacity of bilateral lungs developed rapidly (identified under X-ray fluoroscopy), associated with decrease in lung volume, and then the decrease in SpO2 (94.2±9.2% vs. 59.4±2.2%, P<0.05), and heart rates (143.5±14.3 bpm vs. 58.3±9.7 bpm, P<0.05) followed quickly. TRAL was relieved by supportive oxygen in 32 children (23 with face mask, and 9 with endotracheal intubation), and the duration of TRAL was 1.6±0.5 minutes. However, TRAL caused the death of one child. Conclusions: TRAL is a rare and urgent respiratory complication after ketamine sedation, and the mechanism is unclear. Rapid and diffuse opacity of bilateral lungs is the earliest sign of TRAL in pediatric cardiac catheterization, and the immediate supportive oxygen is crucial.