Abstracts of Posters Presented at the International Anesthesia Research Society; 72nd Clinical and Scientific Congress; Orlando, FL; March 7-11, 1998: Pediatric Anesthesia
While computerized tomography (CT) and magnetic resonance imaging (MRI) pose little risk to children, sedation and general anesthesia (GA) used to facilitate these procedures may add substantial risk for adverse sequelae. This study was designed to examine adverse events and outcomes associated with sedation and with GA for MRI and CT scans in children and to identify risk factors for sedation or GA mishaps outside the operating room.
METHODS: With IRB approval, a quality assurance (QA) tool was completed for all children who underwent sedation or GA for CT or MRI scans. Sedative agents were administered at the discretion of the primary physicians, and care of these children was in accordance with national guidelines.  GA was provided when deemed necessary by the primary physicians, and anesthetic management was at the discretion of the responsible anesthesiologist. QA tools were completed concurrently by the individual responsible for sedation or GA. Data including demographics, ASA status, medications, adverse events, sedation/induction onset, procedure start/end, and discharge times were analyzed using Chi-square, Fisher's exact and unpaired t-tests as appropriate.
RESULTS: To date, 376 children comprise the sedation group, and 48 the GA group. There was no difference in demographics in the 2 groups. The distribution of CT/MRI procedures was 33/67% in the sedation group and 19/77% in the GA group. 2 children in the GA group underwent both CT and MRI scans. The principal reasons for GA use in CT/MRI procedures included prolonged procedures, previous problems with sedation and underlying medical conditions perceived to increase the risk for sedation. 74% of children in the sedation group had received chloral hydrate as the sole sedative. All children in the GA group received inhalational agents and 44% were supplemented with IV medications.
77 (21%) adverse events were reported in the sedation group, compared to 1 (2.1%) in the GA group (Figure 1). Adverse events in the sedation group included inadequate sedation (16%), oxygen desaturation to <or=to 90% of baseline (2.9%), drug reactions (2%) and other events (1.8%). 24 (6%) procedures in this group failed, and 8 of these were resheduled for GA. The one event reported in the GA group was due to equipment failure. 7.9% of children with an ASA 3-4 experienced desaturation compared to 2.3% of those with an ASA 1-2 (p=0.08). Older children were more likely to be inadequately sedated than younger children (p=0.005). Procedure onset time was longer from sedative administration (40.8 +/- 19.5 min) than from induction of GA (20.4 +/- 9.9; p<0.0001). However recovery time as well as the duration of procedure were longer for the GA group (67 +/- 43.5 vs 25 +/- 16 and 182.5 +/- 80.5 vs 101 +/- 38.9 respectively; p<0.0001).
CONCLUSIONS: Our data indicate that children sedated for CT/MRI are at risk for adverse events, and must therefore be closely monitored according to national guidelines.  GA may be necessary for CT and MRI scans in some children and does not appear to increase risk for adverse events. However, children who undergo GA may require a longer stay in the recovery area. Contrary to previous findings,  ASA status and age were not predictive of risk, however a larger sample size is warranted to precisely identify risk factors.
1. Pediatrics 1992;89:1110
2. Anesthesiology 1996;85:A1081