Keyword
Shivering
Pathophysiology
- It is a potentially serious complication that increases oxygen consumption roughly 100% in proportion to intraoperative heat loss
- myocardial ischemia is poorly correlated with shivering, suggesting that an increased metabolic rate is not the primary cause of this complication
- Important determinants of risk : young age and low core temperature
- Opioid-based anesthesia probably reduces thermoregulatory thresholds to an extent similar to that of the potent inhaled agents
Treatment
- Skin surface warming (However, the skin surface contributes only 20% to control of shivering)
- Postanesthetic shivering can also be treated with a variety of drugs, including :
- clonidine (75 µg IV)
- ketanserin (10 mg IV)
- tramadol
- physostigmine (0.04 mg/kg IV)
- nefopam (0.15 mg/kg)
- dexmedetomidine
- magnesium sulfate (30 mg/kg IV).
- Meperidine ( unique among opioids in its ability to effectively terminate or attenuate shivering )
: The antishivering effect of meperidine is primarily related to a reduction in the shivering threshold and seems to be mediated by meperidine's activity on the κ-receptor.Meperidine exerts agonist activity at the α2B-adrenoreceptor subtype, suggesting possible involvement of this novel action in the antishivering action of meperidine
cf)
- Alfetanil, morphine, and fentanyl are not as effective as meperidine in the treatment of postoperative shivering
- Tramadol (0.5 mg/kg) suppressed post–epidural anesthetic shivering in parturients as effectively as meperidine did (0.5 mg/kg)
Reference
Miller’s Anesthesia, 7th edition, Ch.27, P.782