Predictors and clinical implications of shivering during therapeutic normothermia

Neeraj Badjatia, Robert G. Kowalski, J. Michael Schmidt, Marc E. Voorhees, Jan Claassen, Noeleen D. Ostapkovich, Mary Presciutti, E. Sander Connolly, David Palestrant, Augusto Parra, Stephan A. Mayer

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


Background: Shivering during induced normothermia (IN) remains a therapeutic limitation. We investigated potential risk factors and clinical implications of shivering during IN. Methods: Post hoc analysis was performed on 24 patients enrolled in a clinical trial of an automated surface cooling system to achieve IN. Hyponatremia was defined as serum levels <136 mmol/L and hypomagnesaemia as levels <1.5 mg/dL. Continuous heat energy transfer (kcal/h) was averaged hourly. Glasgow Coma Scale (GCS) scores were recorded every 2 h. Shivering status was documented hourly. Mixed effects modeling was used to determine clinical measures associated with shivering. Generalized estimating equation (GEE) models were used to compare baseline-adjusted repeated-measures GCS scores. Results: About of 24 (39%) patients demonstrated shivering. Shivering was associated with men (67% vs. 21%, P = 0.03), hyponatremia (44% vs. 7%, P = 0.03), and hypomagnesaemia (56% vs. 7%, P = 0.02). The average kcal/h (158 ± 645 kcal/h vs. 493 ± 645 kcal/h, P = 0.03) was greater in shivering patients. Shivering was positively associated with increases in heart rate (P < 0.001), respiratory rate (P < 0.001), and kcal/h (P < 0.001). Non-shivering patients showed a greater increase from baseline GCS (GEE, P = 0.02) at 24 h. No differences in sedative doses or fever burden were noted between shiverers and non-shiverers. Conclusions: Men, hyponatremia, and hypomagnesaemia may predispose febrile patients treated with IN to shivering. Shivering dramatically increases the amount of heat transfer required to maintain normothermia, and may be associated with adverse effects on level of consciousness.

Original languageEnglish (US)
Pages (from-to)186-191
Number of pages6
JournalNeurocritical Care
Issue number3
StatePublished - Jun 1 2007


  • Energy expenditure
  • Fever
  • Magnesium
  • Normothermia
  • Shivering

ASJC Scopus subject areas

  • Clinical Neurology
  • Critical Care and Intensive Care Medicine


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