Restlessness and shivering after naloxone reversal of fentanyl-supplemented anaesthesia.
To study the significance of normalization of ventilatory or thermal homeostasis during naloxone reversal, 95 patients were given naloxone after thiopental-N2O-O2-relaxant anaesthesia supplemented with fentanyl (6 microgram/kg/h). If naloxone 0.16 mg was given to combat postoperative apnoea during hypercapnia (end tidal carbon dioxide concentration (ETco2)8%), minute ventilation and respiratory rate were significantly higher during the first minutes as compared to the normocapnic patients. Shivering occurred in 44% in the hypercapnic group, as compared to about 30% if naloxone was given during normocapnia (ETco2 5%). Postoperative pain and restlessness were significantly increased in the hypercapnic group. During normocapnia, untoward reactions were less frequent (40%) if naloxone was given in smaller increments (0.08 + 0.08 mg) rather than in one dose (0.16 mg) (72%). This was mainly due to nausea (8% compared to 32%). The incidence and severity of shivering showed a positive correlation to the duration of anaesthesia (r = 0.42) and to the total amount of fentanyl (r = 0.32), but not to the actual postoperative oesophageal temperature (r = -0.13). The results indicate that though untoward reactions after naloxone reversal are aggravated by naloxone-induced normalization of deranged homeostatic mechanisms, their aetiology probably should be sought in an acute abstinence syndrome.
D000328:Adult; D000368:Aged; D017109:Akathisia, Drug-Induced; D000768:Anesthesia, General; D001831:Body Temperature / Q000187:drug effects; D005260:Female; D005283:Fentanyl; D006706:Homeostasis / Q000187:drug effects; D006801:Humans; D006935:Hypercapnia; D008297:Male; D008875:Middle Aged; D009270:Naloxone / Q000009:adverse effects*; D009609:Nitrous Oxide; D012119:Respiration / Q000187:drug effects; D012768:Shivering; D013874:Thiopental
D009270:Naloxone; D013874:Thiopental; D009609:Nitrous Oxide; D005283:Fentanyl