Use of microstream capnography in sedation practices for pediatric patients undergoing magnetic resonance imaging

Abstract

In pediatric magnetic resonance imaging (MRI), there is a need for more advanced monitoring methods in addition to routine pulse oximetry to ensure safer nonoperating room anesthesia (NORA). The integrated pulmonary index (IPI) available in the Microstream capnography device provides an early indicator of a patient’s respiratory functions. In this study, we aimed to investigate the feasibility of using the IPI as an early indicator for detecting cardiorespiratory events. A prospective, observational study was conducted on pediatric patients aged 1 month to 18 years who were to undergo sedation for magnetic resonance imaging (MRI). The respiratory rate (RR), end tidal carbon dioxide (EtCO 2 ), oxygen saturation (SpO 2 ), heart rate (HR), complications, and EtCO 2 changes (∆EtCO 2 ) were recorded. IPI values at induction and at the end of the scan were evaluated. The primary outcome was the diagnostic performance of the post-induction IPI value in predicting cardiorespiratory events; secondary outcomes included the incidence of cardiorespiratory events and of hypopneic hypoventilation, and the diagnostic performance of EtCO 2 for these outcomes. A total of 159 patients were included in the study. ROC analysis revealed the diagnostic significance of EtCO 2 induction in predicting hypoxia and apnea. While 31.44% of all patients had ∆EtCO 2 , only 6.3% of these patients had SpO 2 ≤ 93% (hypoxia) at the same time. The induction EtCO 2 median in patients who developed hypoxia was 26 mmHg (IQR: 14–29), compared to 33 mmHg (IQR: 28–36) in those without hypoxia ( p = 0.001). EtCO 2 The optimal threshold value was found to be 29 mmHg in patients who developed hypoxia, whereas it was 18 mmHg in those who developed apnea. A total of 27.7% of all patients had hypopneic hypoventilation, and hypoxia was detected in %15.9 of these patients. IPI, EtCO 2 , and ∆EtCO 2 have a statistically significant effect on ‘induction cardiorespiratory events’. Patients with cardiorespiratory events had an IPI ≤ 6 and EtCO 2 ≤ 33. Each one-unit increase in IPI was calculated to reduce the probability of a cardiorespiratory event by approximately 46.3%. Severe respiratory complications are frequently observed in young pediatric patients undergoing NORA. Early diagnosis of respiratory complications, particularly hypopneic hypoventilation, is possible through EtCO 2 monitoring. Low EtCO 2 and IPI are considered potential risk factors for the development of cardiorespiratory events. The routine use of capnography, a method that allows continuous and noninvasive monitoring of respiration, enhances patient safety in procedural sedation outside the operating room. Intervention in pediatric patients with an IPI value < 6 who develop cardiovascular events is considered necessary. Because EtCO 2 is sampled outside the airway, continuous auscultation of breath sounds is recommended as a complementary monitor in this setting. Registry : ClinicalTrials.gov, TRN: NCT04622436, Registration date: 03 November 2020.