During the first two to three days after a major abdominal operation, most patients have frequent episodes of airway obstruction and hypoxaemia. This can lead to an increase in the heart rate and blood pressure, which can eventually result in heart muscle damage. An apparently restful patient where nothing seems to be wrong can then suddenly experience an unexpected heart attack.
The breathing problems are a side effect of the necessary sedatives and painkillers which recovering patients receive. The researchers from Leiden discovered that the medicines enhance each other's undesirable side effects.
In searching for the mechanism behind the breathing problems, it transpired that the administration of vitamins C and E prevents many of the problems. After an encouraging experiment with vitamins C and E on an experimental animal, the researchers subjected 34 healthy men to a test. The volunteers received less oxygen than normal for a period of three minutes. Prior to this some of the men had to take sedatives and vitamins C and E. Another group were not allowed vitamins.
The group who had taken vitamins experienced fewer disruptions to the breathing than the control group who had not taken vitamins. The researchers suspect that stress and pain after an invasive operation bring about a positive effect. Stress and pain keep the body, and thereby the breathing, relatively alert.
In follow-on studies the researchers want to determine whether vitamin C has to be given in combination with vitamin E. They will also study other sorts of sedatives and painkillers. In addition to this they will further examine the role of stress and pain after an operation. Particular attention will be given to the carotid body, a special organ in the carotid artery. This organ seems to function poorly in recovering patients.
Further information can be obtained from Dr Diederik Nieuwenhuijs (Department of Anaesthesiology, Leiden University Medical Center), tel. 31-71-526-2301 (secretariat), fax 31-71-524-8230 (secretariat), e-mail d.j.f.nieuwenhuijs@lumc.nl . The defence of the doctoral thesis took place on 4 September 2002. Dr Nieuwenhuijs' supervisor was Prof. J.W. van Kleef.
The research was funded by the Netherlands Organisation for Scientific Research (NWO).