Delayed postoperative gastric emptying following intrathecal morphine and intrathecal bupivacaine.
OBJECTIVE
A decrease in the rate of gastric emptying can delay resumption of enteral feeding, alter bioavailability of orally administered drugs, and result in larger residual gastric volumes, increasing the risk of nausea and vomiting. We compared the effects of 1) intrathecal bupivacaine (17.5 mg) and 2) the combination of intrathecal morphine (0.6 mg) and intrathecal bupivacaine (17.5 mg) on the rate of gastric emptying in patients undergoing elective hip arthroplasty.


METHODS
Twenty four fasting ASA 1-3 patients were randomly assigned, in a double blind manner, to receive intrathecal hyperbaric bupivacaine (17.5 mg), either alone (group 1), or followed by intrathecal morphine (0.6 mg) (group 2). Gastric emptying was measured (using an acetaminophen absorption technique), twice in each patient; preoperatively, and approximately one hour postoperatively. Gastric emptying parameters are: AUC (area under the plasma acetaminophen concentration time curve), maximum plasma acetaminophen concentration (Cmax), and time to Cmax (tCmax), analyzed using paired Student's t tests.


RESULTS
Gastric emptying rates were reduced in both group 1 (AUC = 14.98 (3.8) and 11.05 (4.6) pre- and postoperatively, respectively) and group 2 (AUC = 13.93 (3.59) and 6.4 (3.42) pre- and postoperatively, respectively); the magnitude of the reduction was greater in group 2 [AUC (P = 0.04), Cmax (P = 0.05), tCmax (P = 0.13)].


CONCLUSIONS
The combination of intrathecal morphine (0.6 mg) and intrathecal bupivacaine (17.5 mg) delays gastric emptying postoperatively.
Lydon
A M
AM
Department of Anaesthesia and Intensive Care Medicine, Cork University Hospital and University College Cork, Ireland.
Cooke
T
T
Duggan
F
F
Shorten
G D
GD
D000042:Absorption; D000082:Acetaminophen / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D000284:Administration, Oral; D000368:Aged; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D000701:Analgesics, Opioid / Q000008:administration & dosage*; D000775:Anesthesia, Spinal; D000779:Anesthetics, Local / Q000008:administration & dosage*; D019540:Area Under Curve; D001682:Biological Availability; D002045:Bupivacaine / Q000008:administration & dosage*; D004311:Double-Blind Method; D004750:Enteral Nutrition; D005260:Female; D005500:Follow-Up Studies; D005746:Gastric Emptying / Q000187:drug effects*; D006801:Humans; D007278:Injections, Spinal; D008297:Male; D009020:Morphine / Q000008:administration & dosage*; D020250:Postoperative Nausea and Vomiting / Q000209:etiology; D011184:Postoperative Period; D012307:Risk Factors; D013997:Time Factors
D018712:Analgesics, Non-Narcotic; D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D000082:Acetaminophen; D009020:Morphine; D002045:Bupivacaine