The use of nerve blocks for studying cardiopulmonary physiology in man.

Anaesthetists employ nerve blocks for purposes other than providing surgical anaesthesia; that is, for diagnosis, therapy, and clinical investigation. In this regard the anaesthetist is in a unique position to make physiological observations in normal as well as abnormal subjects during nerve block procedures. Areas of specific importance to both physiologists and clinicians concern the innervation of the heart and the lungs. Cardiac and pulmonary sympathetic blockade is frequently produced in the course of spinal and peridural anaesthesia. Less frequently, block of the vagus or phrenic has been performed for special situations. Certainly it is feasible to block selectively the sympathetic, parasympathetic, and somatic nerves to the heart and lungs or the entire thorax. It is the purpose of this paper to bring together information obtained during nerve block procedures involving the heart and lungs and to suggest questions that could be answered by a concerted approach of anaesthetists.