Table 2.

Consequences of IPH

SSI	IPH leads to decreased blood flow and decreased oxygen flux to the tissues; oxygen tension is directly related to oxidative neutrophil destruction of bacteria for 4 h after exposure Hypothermia reduces superoxide radical production at any given oxygen tension
Drug metabolism	MAC for isoflurane decreases by 5% per 1°C decrease in core temperature Tissue solubility of volatile anaesthetics increases with hypothermia, causing delayed recovery Hepatic metabolism is reduced, leading to the prolonged action of propofol and opiates Longer action of neuromuscular block is caused by reduced hepatic metabolism and decreased rate of Hoffman degradation
Increased bleeding and transfusion requirements	Impaired platelet function Impaired coagulation cascade Temperatures at 35.5°C have been shown to increase the relative risk of transfusion by 22%4
Increased rate of cardiac events	Mediated by increased postoperative catecholamine concentrations leading to increased arterial BP which increases myocardial workload Ischaemic cardiac events may also be compounded by the increased skeletal muscle oxygen demand of any concomitant shivering5
Shivering	Increases postoperative pain and makes monitoring unreliable Independently increases carbon dioxide production, catecholamine release, and cardiac output