Effects of shivering prevention on haemodynamic and metabolic demands in hypothermic postoperative neurosurgical patients

Abstract

We evaluated the haemodynamic and metabolic effects of prevention of shivering after prophylactic nefopam administration in neurosurgical patients undergoing craniotomy and mild systemic hypothermia (33-35 degrees C). Forty patients were enrolled in a randomised, double-blind study. Before extubation, patients received intravenously either nefopam 0.12 mg.kg-1 or an equal volume of saline 0.9%. Left ventricular systolic work index, oxygen consumption index and systemic lactate concentration were recorded before, immediately after and every 20 min for 2 h after extubation. Shivering appeared in two patients treated with nefopam and in all control patients (p < 0.001). Both left ventricular systolic work index and oxygen consumption index were similar in the two groups before extubation, increased after extubation, and further increased in control patients showing a statistical difference compared to patients treated with nefopam. Our results suggest that nefopam is effective in preventing postoperative shivering in patients undergoing neurosurgery and mild hypothermia and attenuates the haemodynamic effects of shivering during rewarming.

Nefopam or clonidine in the pharmacologic prevention of shivering in patients undergoing conscious sedation for interventional neuroradiology

“…Although the mechanisms underlying the analgesic action of nefopam are unclear, the drug does not bind to opiate receptors, but inhibits synaptic uptake of several neurotransmitters, including dopamine, norepinephrine and serotonin [19,20]. Ample evidence confirms the efficacy of nefopam for the treatment [2] and prevention [4][5][6] of postanaesthetic shivering. Our findings now confirm its efficacy for preventing peri-operative shivering in patients undergoing conscious sedation.…”

“…Although numerous papers have addressed the problem of postoperative shivering after general anaesthesia and during neuraxial anaesthesia [1][2][3][4][5][6], none have investigated the troublesome problem of shivering during and after conscious sedation. For interventional neuroradiology, the preferred anaesthetic technique is conscious sedation.…”

“…Pharmacological prevention minimises the increase in metabolic activity and cardiac work [5]. Nefopam (3,4,5,6-tetrahydro-5-methyl-l-phenyl-1H-2.5-benoxazocine hydrochloride) is a non-opioid analgesic drug that is safe and effective in preventing shivering after general and neuraxial anaesthesia with little effect on the sweating and vasoconstriction thresholds [2,[4][5][6]13].…”

“…Shivering can be prevented by maintaining normothermia [11,12] or pharmacologically [1][2][3][4][5][6]. Pharmacological prevention minimises the increase in metabolic activity and cardiac work [5].…”

“…In this setting, shivering is common and can be caused by hypothermia, central thermoregulatory downregulation, pyrogens and injected iodine-containing contrast media. Shivering increases cardiac and systemic energy demands, oxygen consumption and carbon dioxide production and cardiac workload [5,7]. If ventilation and cardiac output do not increase proportionally, hypoxaemia and mixed respiratory and lactic acidosis develop [8].…”