Ketamine-midazolam total intravenous anaesthesia for prolonged abdominal surgery.
OBJECTIVE
Infusion of ketamine and midazolam can maintain prolonged anaesthesia, but delayed recovery is a limitation. We aimed to develop an approximation regimen for the infusion of ketamine and midazolam to obtain steady-state anaesthesia with acceptable recovery.


METHODS
Thirty-one patients undergoing radical cystectomy were studied. The initial regimen was calculated from drug pharmacokinetic variables and tailored in a pilot study (15 patients) to develop the approximation regimen dosage. Anaesthesia was induced with midazolam (150 micrograms kg-1) and ketamine (2 mg kg-1). Tracheal intubation and ventilation with oxygen enriched air (FiO2 = 0.35) were facilitated by muscle relaxants. Anaesthesia was maintained by the approximation regimen doses. Routine monitoring was used for all patients, but pulmonary artery catheters were inserted in 11 patients, to obtain haemodynamic and oxygenation variables.


RESULTS
Steady-state anaesthesia was obtained with minimal deviations in the regimen in some patients followed by reasonable recovery.


CONCLUSIONS
It is concluded that infusion of ketamine and midazolam in the approximation regimen doses can be used to maintain anaesthesia for prolonged abdominal surgery.
Department of Anaesthesia, Urology & Nephrology Centre, University of Mansoura, Mansoura, Egypt.
M M
MM
Atallah
H A
HA
el-Mohayman
R E
RE
el-Metwally
D000005:Abdomen / Q000601:surgery*; D000328:Adult; D000368:Aged; D000771:Anesthesia, Intravenous; D000778:Anesthetics, Dissociative / Q000008:administration & dosage; D018686:Anesthetics, Intravenous / Q000008:administration & dosage; D001364:Awareness; D015653:Cystectomy; D005260:Female; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007432:Intraoperative Period; D007649:Ketamine / Q000008:administration & dosage; D008297:Male; D008874:Midazolam / Q000008:administration & dosage; D008875:Middle Aged; D010101:Oxygen Consumption; D010865:Pilot Projects; D011446:Prospective Studies; D012121:Respiration, Artificial; D013997:Time Factors
D000778:Anesthetics, Dissociative; D018686:Anesthetics, Intravenous; D007649:Ketamine; D008874:Midazolam