P V van Heerden, P D Cameron, A Karanovic, M A Goodman. Anaesthesia and Intensive Care. Edgecliff:Oct 2003. Vol. 31, Iss. 5, p. 581-3
We present a case of orthodeoxia (postural hypoxaemia) which resulted from a combination of lung collapse/consolidation and blunted hypoxic pulmonary vasoconstriction due to partial interruption of the sympathetic nerve supply to the lung by bilateral thoracic sympathectomy.
Less common associations with orthodeoxia are atypical pneumonia3, trauma8, organophosphate poisoning10 and progressive autonomic failure12.
The surgical procedure, which interrupted both sympathetic trunks, probably resulted in "sympathectomy" of the lung with consequent vasoplegia of the pulmonary circulation and blunting of the HPV response.
The combination of areas of reduced ventilation in the lung, together with blunted HPV, resulted in profound oxygen desaturation in our patient when she sat up in bed.
As antibiotics and chest physiotherapy improved the collapse/consolidation of the lungs, the patient became less dependent on artificial means of maintaining pulmonary vascular tone, so that the noradrenaline and then the almitrine could be weaned without incident. Presumably there will be some return of sympathetic tone to the pulmonary circulation with time.
It was not the intention of the authors to describe all the physiological consequences of thoracotomy or thoracoscopy, with or without one-lung ventilation, in this short communication. Clearly these procedures on their own can have significant effects on lung physiology, quite apart from the unique confluence of factors producing orthodeoxia in the patient presented in this case report.
