ABSTRACT
BACKGROUND: Maintaining normocapnia during mechanical ventilation in anesthetized children during laparoscopic surgeries is highly recommended. There is a debate regarding the use of capnography (ETCO2) as a trend monitor for evaluation of arterial carbon dioxide levels (PaCO2). We analyzed the relationship between ETCO2 and PaCO2 with time in elective pediatric laparoscopic surgeries. METHODS: This study was a prospective observational cohort analysis of 116 paired comparisons between PaCO2 and ETCO2 computed from 29 children (ASA I, 12-72 months). Arterial blood samples were withdrawn before, at 15 minutes and 30 minutes during pneumoperitoneum and 1 minute after deflation. ETCO2 value was recorded simultaneously, while arterial blood was withdrawn. PaCO2-ETCO2 relationship was evaluated by Pearson's correlation coefficients and Bland Altman Method of agreement. RESULTS: Out of the 116 comparisons analyzed, a PaCO2-ETCO2 difference beyond 0 to ≤ 5 mmHg was recorded in 71 comparisons (61.2%) with negative difference in 34 comparisons (29.3%). A positive significant correlation between PaCO2 and ETCO2 was recorded before (r = 0.617, p = 0.000) and at 15 minutes (r = 0.582, p = 0.001), with no significant correlation at 30 minutes (r = 0.142, p = 0.461), either after deflation (r = 0.108, p = 0.577). Bland-Altman plots showed agreement between ETCO2 and PaCO2 before inflation with mean PaCO2-ETCO2 difference 0.14 ± 5.6 mmHg (limits of 95% agreement -10.84-11.2, simple linear regression testing p-value 0.971), with no agreement at 15 minutes (0.51 ± 7.15, -13.5-14.5, p = 0.000), 30 minutes. (2.62 ± 7.83, -12.73-17.97, p = 0.000), or after deflation (1.81 ± 6.56, -10.93-14.55, p = 0.015). CONCLUSION: Usage of capnography as a trend monitor in pediatric laparoscopic surgeries may not be a reliable surrogate for PaCO2 levels. TRIAL REGISTRATION: Clinical Trials. gov (Identifier: NCT03361657).
