The Hematological Effects of Nitrous Oxide Anesthesia in Pediatric Patients. (June 2015)

• Record Type: Journal Article
• Authors: Duma, Andreas; Cartmill, Christopher; Blood, Jane; Sharma, Anshuman; Kharasch, Evan D.; Nagele, Peter
• Is Part Of: Anesthesia & analgesia. Volume 120:Number 6(2015)
• Publication Date: 2015-06
• Subjects: Anesthesiology -- Periodicals; Anesthesia; Anesthesiology; Analgesia; Analgesics; Anesthesiology -- Periodicals; 617.9605
• DOI: 10.1213/ANE.0000000000000642
• Languages: English
• ISSNs: 0003-2999

Abstract

<abstract> <title> <x xml:space="preserve">Abstract</x> </title> <sec> <title>BACKGROUND:</title> <p>Prolonged administration of nitrous oxide causes an increase in plasma homocysteine in children via vitamin B<sub>12</sub> inactivation. However, it is unclear whether nitrous oxide doses used in clinical practice cause adverse hematological effects in pediatric patients.</p> </sec> <sec> <title>METHODS:</title> <p>This retrospective study included 54 pediatric patients undergoing elective spinal surgery: 41 received nitrous oxide throughout anesthesia (maintenance group), 9 received nitrous oxide for induction and/or emergence (induction/emergence group), and 4 did not receive nitrous oxide (nitrous oxide–free group). Complete blood counts obtained before and up to 4 days after surgery were assessed for anemia, macrocytosis/microcytosis, anisocytosis, hyperchromatosis/hypochromatosis, thrombocytopenia, and leukopenia. The change (Δ) from preoperative to the highest postoperative value was calculated for mean corpuscular volume (MCV) and red cell distribution width (RDW).</p> </sec> <sec> <title>RESULTS:</title> <p>No pancytopenia was present in any patient after surgery. All patients had postoperative anemia, and none had macrocytosis. Postoperative MCV (mean [99% confidence interval]) peaked at 86 fL (85–88 fL), 85 fL (81–89 fL), and 88 fL (80–96 fL) and postoperative RDW at 13.2% (12.8–13.5%), 13.3% (12.7–13.8%), and 13.0% (11.4–14.6%) for the maintenance group, the induction/emergence group, and the nitrous oxide–free group. Two patients in the maintenance group (5%) developed anisocytosis (RDW >14.6%), but none in the induction/emergence group or in the nitrous oxide–free group (<italic>P</italic> = 0.43). Both ΔMCV (<italic>P</italic> = 0.52) and ΔRDW (<italic>P</italic> = 0.16) were similar across all groups.</p> </sec> <sec> <title>CONCLUSIONS:</title> <p>Nitrous oxide exposure for up to 8 hours is not associated with megaloblastic anemia in pediatric patients undergoing major spinal surgery.</p> </sec> </abstract>