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Relationship Between Pain Severity and Serum β‐Endorphin Levels in Postoperative Patients
Author(s) -
Leonard Theresa M.,
Klem Stephen A.,
Asher Marc A.,
Rapoff Michael A.,
Leff Richard D.
Publication year - 1993
Publication title -
pharmacotherapy: the journal of human pharmacology and drug therapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.227
H-Index - 109
eISSN - 1875-9114
pISSN - 0277-0008
DOI - 10.1002/j.1875-9114.1993.tb02745.x
Subject(s) - medicine , morphine , anesthesia , blood sampling , prospective cohort study , pain scale , surgery
Study Objective . To examine the relationship among postoperative pain severity, serum β‐endorphin level, and serum morphine level in pediatric patients after posterior spinal fusion with instrumentation. Design . A prospective study. Setting . University‐based medical center. Patients . Ten patients age 13–17 years admitted for posterior spinal fusion with instrumentation. Interventions . Each subject was administered an initial dose of intravenous morphine 100 μg/kg, followed by a constant infusion of 50 μg/kg/hour. The primary physician was allowed to titrate the dosage as required to meet the patient's requirement for analgesia. Whole blood was obtained for the analysis of serum morphine and β‐endorphin levels preoperatively, after the initial morphine dose, 24 hours after initiation of the infusion, and before any change in dosage. At each blood sampling time, pain severity ratings were obtained from the subject, nurse, and parent using a 10‐point linear scale. Measurements and Main Results . No statistical difference between serum β‐endorphin values preoperatively and after the initial dose of morphine was observed; mean values were 68 and 60 pg/ml, respectively. The relationships between serum β‐endorphin level and pain scores were statistically significant only for self (subject) pain scores (p=0.014, r=‐0.30). Mean serum morphine level was 21.9 ng/ml for patients with self pain scores of 4 or less. Conclusion . The clinical usefulness of serum β‐endorphin as a measure of pain severity was not established under the experimental conditions of this study.