Cerebral Oxygen Metabolism Before and After RBC Transfusion in Infants Following Major Surgical Procedures.

OBJECTIVE: Although infants following major surgery frequently require RBC transfusions, there is still controversy concerning the best definition for requirement of transfusion in the individual patient. The aim of this study was to determine the impact of RBC transfusion on cerebral oxygen metabolism in noncardiac and cardiac postsurgical infants. DESIGN: Prospective observational cohort study. SETTING: Pediatric critical care unit of a tertiary referral center. PATIENTS: Fifty-eight infants (15 after pediatric surgery and 43 after cardiac surgery) with anemia requiring RBC transfusion were included. INTERVENTIONS: RBC transfusion. MEASUREMENTS AND MAIN RESULTS: We measured noninvasively regional cerebral oxygen saturation and microperfusion (relative cerebral blood flow) using tissue spectrometry and laser Doppler flowmetry before and after RBC transfusion. Cerebral fractional tissue oxygen extraction and approximated cerebral metabolic rate of oxygen were calculated. Fifty-eight RBC transfusions in 58 patients were monitored (15 after general surgery, 24 after cardiac surgery resulting in acyanotic biventricular physiology and 19 in functionally univentricular hearts including hypoplastic left heart following neonatal palliation). The posttransfusion hemoglobin concentrations increased significantly (9.7 g/dL vs 12.8 g/dL; 9.7 g/dL vs 13.8 g/dL; 13.1 g/dL vs 15.6 g/dL; p < 0.001, respectively). Posttransfusion cerebral oxygen saturation was significantly higher than pretransfusion (61% [51-78] vs 72% [59-89]; p < 0.001; 58% [35-77] vs 71% [57-88]; p < 0.001; 51% [37-61] vs 58% [42-73]; p = 0.007). Cerebral fractional tissue oxygen extraction decreased posttransfusion significantly 0.37 (0.16-0.47) and 0.27 (0.07-039), p = 0.002; 0.40 (0.2-0.62) vs 0.26 (0.11-0.57), p = 0.001; 0.42 (0.23-0.52) vs 0.32 (0.1-0.42), p = 0.017. Cerebral blood flow and approximated cerebral metabolic rate of oxygen showed no significant change during the observation period. The increase in cerebral oxygen saturation and the decrease in cerebral fractional tissue oxygen extraction were most pronounced in patients after cardiac surgery with a pretransfusion cerebral fractional tissue oxygen extraction greater than or equal to 0.4. CONCLUSION: Following RBC transfusion, cerebral oxygen saturation increases and cerebral fractional tissue oxygen extraction decreases. The data suggest that cerebral oxygenation in postoperative infants with cerebral fractional tissue oxygen extraction greater than or equal to 0.4 may be at risk in instable hemodynamic or respiratory situations.

Ketamine Infusion as a Counter Measure for Opioid Tolerance in Mechanically Ventilated Children: A Pilot Study.

BACKGROUND: Drug rotation to prevent opioid tolerance is well recognized in chronic pain management. However, ketamine infusion as a counter measure for opioid tolerance is rarely described in mechanically ventilated children developing tolerance from prolonged opioid infusion. PATIENTS AND METHODS: We performed a retrospective study in a 14-bed medical-surgical-cardiac pediatric intensive care unit. Thirty-two mechanically ventilated children who had developed tolerance from prolonged intravenous infusion of opioids received a continuous intravenous infusion of ketamine as an opioid substitute for more than 2 days, scheduled in a drug rotation protocol. RESULTS: Thirty-two children (median age 2.5 years, range 0.1-16.0; weight 11.2 kg [3.8-62.0]) were included. Patients had received continuous intravenous infusion of opioids and benzodiazepines for 16.0 days (4.0-34.0) when drug rotation was started. The median dose of continuous intravenous infusion of ketamine was 4.0 mg·kg-1·h-1 (1.8-6.0) and the median duration was 3.0 days (2.0-6.0). After having restarted opioids, fentanyl doses were significantly lower compared with the time before the drug rotation began (after, 2.9 µg·kg-1·h-1 [0.8-4.9] vs before, 4.15 µg·kg-1·h-1 [1.2-10.0]; p < 0.001). Continuous intravenous infusion of midazolam and clonidine were unchanged during drug rotation. COMFORT-B scoring was significantly lower after having started drug rotation (after, 14.5 [8-19] vs before, 16 [11-22]; p < 0.001). CONCLUSION: Drug rotation with ketamine in mechanically ventilated children with opioid tolerance is feasible and seems to reduce the rate of fentanyl infusion.

Analgesia and Sedation Protocol for Mechanically Ventilated Postsurgical Children Reduces Benzodiazepines and Withdrawal Symptoms-But Not in All Patients.

Background We demonstrated recently that the implementation of a nurse-driven analgesia and sedation protocol (pediatric analgesia and sedation protocol [pASP]) for mechanically ventilated nonpostsurgical patients reduces the total dose of benzodiazepines and the withdrawal symptoms significantly. It has not been investigated if these results can also be expected in the group of patients undergoing surgery. Objectives To evaluate the effects of the pASP in mechanically ventilated postsurgical children regarding drug dosage, duration of mechanical ventilation, length of stay, and rate of withdrawal symptoms. Methods This is a two-phase prospective observational control study. The preimplementation group was managed by the physician's order and the postimplementation group was managed with the pASP including COMFORT-B, nurse interpretation of sedation, and Sophia observation withdrawal symptoms scale scoring. Measurements and Main Results One hundred and sixteen patients were included before and one hundred and ten patients after implementation. The pASP had no effect on length of pediatric intensive care unit stay or duration of mechanical ventilation. The protocol reduced total (5.0 mg/kg [0.5-58.0] vs 4.0 mg/kg [0.0-47.0]; p = 0.021) and daily doses (4.4 mg/kg/d [1.1-33.9] vs 2.9 mg/kg/d [0.0-9.9]; p < 0.001) of benzodiazepines significantly. No difference was observed in total and daily doses of opioids (5.0 mg/kg [0.1-67.0] vs 3.0 mg/kg [0.1-71.0]; p = 0.81) and (0.7 mg/kg/d [0.0-7.0] vs. 0.8 mg/kg/d [0.0-3.7]; p = 0.35), respectively. Rate of withdrawal symptoms was significantly lower after implementation (35.3 vs 20.0%; p = 0.01), but not in patients after solid organ transplantation or oncological patients. Conclusion The nurse-driven analgesia and sedation protocol is an effective procedure to reduce the total doses of benzodiazepines and occurrence of withdrawal symptoms in postsurgical children, which are naïve to opioids or benzodiazepines.