Remifentanil for cesarean section under general anesthesia: effects on maternal stress hormone secretion and neonatal well-being: a randomized trial.
BACKGROUND
Remifentanil may attenuate maternal hemodynamic response during cesarean section under general anesthesia, but could cause transient but significant neonatal depression. We investigated the effect of low-dose remifentanil on maternal neuroendocrine response and fetal wellbeing.


METHODS
Forty-two ASA I-II parturients undergoing cesarean section at term under general anesthesia were randomized to receive either fentanyl after delivery (n=21, group C) or remifentanil bolus 0.5 microg/kg before induction followed by a continuous infusion at 0.15 microg x kg(-1)min(-1) until peritoneal incision, then restarted after delivery (n=21, group R). Maternal heart rate and blood pressure, and epinephrine, norepinephrine, adrenocorticotropic hormone (ACTH), and growth hormone levels were measured at baseline, uterine incision, and the end of surgery. Remifentanil was measured in maternal and umbilical arterial and venous blood. One- and 5-minute Apgar scores and umbilical arterial and venous pH were recorded.


RESULTS
ACTH was significantly higher in group C at uterine incision (P<0.01). No significant differences were observed in hemodynamics, catecholamines or growth hormone. Apgar scores at 1 (P<0.05) and 5 min (P<0.01) were significantly higher in group C. Mean umbilical pH values were within normal range but significantly higher in group C. Three neonates in group R required intubation but recovered at 5 min without naloxone. Mean+/-SD maternal remifentanil concentration was 1.67+/-1.04 ng/mL.


CONCLUSIONS
Remifentanil administration before peritoneal incision partially reduced the hormonal stress response. Maternal benefits must be weighed against transitory but significant neonatal respiratory depression. Neonatal resuscitation facilities are mandatory when remifentanil is used.
Draisci
G
G
Istituto di Anestesiologia e Rianimazione, Dipartimento di Emergenza e Accettazione Istituto di Chimica Clinica, Università Cattolica del Sacro Cuore, Istituto Superiore di Sanità, Rome, Italy. gdraisci@inwind.it
Valente
A
A
Suppa
E
E
Frassanito
L
L
Pinto
R
R
Meo
F
F
De Sole
P
P
Bossù
E
E
Zanfini
B A
BA
D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects*; D000768:Anesthesia, General / Q000379:methods; D000773:Anesthesia, Obstetrical / Q000379:methods; D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000187:drug effects; D002585:Cesarean Section; D004837:Epinephrine / Q000097:blood; D005260:Female; D013006:Growth Hormone / Q000097:blood; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007231:Infant, Newborn; D009638:Norepinephrine / Q000097:blood; D010880:Piperidines / Q000008:administration & dosage / Q000009:adverse effects*; D011181:Postnatal Care / Q000379:methods; D011247:Pregnancy; D011256:Pregnancy Outcome; D000077208:Remifentanil; D016037:Single-Blind Method; D013312:Stress, Physiological / Q000097:blood / Q000188:drug therapy
D000701:Analgesics, Opioid; D010880:Piperidines; D000324:Adrenocorticotropic Hormone; D013006:Growth Hormone; D000077208:Remifentanil; D009638:Norepinephrine; D004837:Epinephrine