Prevention of atelectasis secondary to propofol-based general anesthesia by application of continuous positive airway pressure to children with neuroblastoma undergoing computerized tomography: a quality improvement project

Abstract

Atelectasis is a well-known complication of general anesthesia (GA) and intravenous propofol sedation [1][2][3][4]. Incidence of anesthesia-induced atelectasis is higher in younger age [4,5]. In children with neuroblastoma, false uptake of metaiodobenzylguanidine (MIBG) in the lung due to atelectasis has been reported [6], which can obscure images of pulmonary metastases [7]. However, the incidence and severity of atelectasis in children receiving SPECT/PET/CT has not been delineated. Due to concerns of atelectasis confounding imaging quality in younger children, we implemented a new protocol to reduce atelectasis risk with continuous positive airway pressure (CPAP). MethodsAfter IRB approval, imaging of children with neuroblastoma from the ages of 1 month to 10 years old was analyzed. Prior to the protocol change, we used an intravenous propofol infusion (150-250 mcg/kg/min) with nasal cannula. Following the protocol change, children's airway was supported with a laryngeal mask airway (LMA) or an anesthesia mask with a strap connected to a Jackson-Rees circuit (Fig. 1). Air blender (FiO 2 < 30%) was used to prevent absorption atelectasis [8]. Higher propofol infusion rate (250-300 mcg/kg/min) was used to allow children to tolerate in situ airway. Air flow and AP valve in the circuit were adjusted to maintain CPAP (5 to 10 cmH 2 O) [5]. We titrated infusion rate according to respiratory parameter (SpO2 > 95%) and hemodynamical parameter (mean arterial pressure above 40 mmHg).A single, blinded pediatric radiologist graded the severity of atelectasis according to previously described scale [7] and determined whether there was significant atelectasis to confound image quality or not.Statistics were calculated using Mcnemar's test due to paired observations from children receiving imaging both pre-and post-protocol implementation. ResultsNine children underwent both pre-and post-protocol, but demographics of those at different time points of SPECT/PET/CT were very similar. The incidence of significant atelectasis in the "pre-protocol" sedation was 3/9 (33.3%) vs 0/9 patients (0.0%) in the "post-protocol" (p value = 0.04). DiscussionOur observations among the nine children who underwent intravenous propofol infusion with and without CPAP at different time points showed a significant reduction in the incidence and severity of atelectasis with CPAP. Our new protocol is unique because we were able to achieve CPAP without the use of an anesthesia ventilator. The results of our study need to be considered in light of its limitations. Due to a small sample size and the retrospective nature of the study, we could not pinpoint the role of patient factors. The grading scale was developed by a single radiologist and has not been validated. We encourage larger, randomized studies to elucidate the effect of propofol anesthesia on the imaging