Respiratory depression remifentanil

In two randomized, double-blind, controlled comparisons of anesthetic techniques for extracorporeal shock wave lithotripsy remifentanil infusion had no advantage over the combination of fentanyl bolus plus propofol infusion, but caused more adverse effects (nausea and vomiting) (10). In another study remifentanil infusion provided comparable analgesia and caused less respiratory depression and fewer gastrointestinal symptoms than intravenous boluses of sufentanil (11). 

The respiratory depressant and gastrointestinal adverse effects of remifentanil have been observed in a randomized, single-blind study of 125 patients undergoing elective orthopedic and urological surgery under spinal or brachial plexus anesthesia (16). They were randomized to either remifentanil (a bolus of 0.5 micrograms/kg plus an infusion of 0.1 micrograms/kg/minute) or propofol... 

In a double-blind, randomized, placebo-controlled study in 28 adults undergoing carotid endarterectomy, remifentanil provided adequate analgesia, and supplementary local anesthetics were not needed (17). The remifentanil infusion rate was as low as 0.04 micrograms/kg/minute and there were no episodes of respiratory depression or hemodynamic instability. 

Remifentanil is liable to cause respiratory depression in children (33,34), as well as muscle rigidity, hypotension, and bradycardia, without increasing the incidence of gastrointestinal symptoms (35). 

Another study in healthy subjects using various experimental pain models found that ketamine antagonised the respiratory depressant effect of remifentanil. Remifentanil alone produced analgesic effects with all pain tests, but ketamine only enhanced the effect of remifentanil on intramuscular electrical stimulation. Acute remifentanil-induced hyperalgesia and tolerance were detected only by the pressure pain test and were not suppressed by ketamine. The combined effects of remifentanil and ketamine probably depend on the type of pain. ... 

Susceptibflity factors Age The use of remifentanil in neonates and premature infants has been reviewed. Adverse reactions were similar to other opioids (bradycardia, hypotension, respiratory depression, chest waU rigidity, nausea, and vomiting) but were less frequent and less severe [177 ]. 

Due to its potential for respiratory depression, remifentanil is not recommended for post-operative analgesia, except in mechanically ventilated patients in a properly supervised environment. 

Side effects remifentanil may cause adverse effects characteristic of p opioids, such as respiratory depression, bradycardia, hypotension, primitus, and skeletal muscle rigidity. 

Observational studies When remifentanil was given by intravenous infusion pump at a rate of 0.1-0.15 micrograms/kg/minute to 186 patients undergoing percutaneous transhepatic biliary drainage (mean total dose 116 micrograms), 10% had transient bradycardia and 2% had respiratory depression [160 ]. 

Drug tolerance Tolerance to remifentanil has been studied after short-term administration of remifentanil to 36 healthy volunteers [165 ]. After a 3-hour infusion its analgesic potency fell by 5-24%, the risk of respiratory depression fell by 20-48%, and the risk of sedative effects fell by 32%. The authors concluded that short-term clinically useful doses of remifentanil were not associated with significant tolerance. 

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