The postural effects on blood pressure following interruption of the vasomotor nerves of man

Abstract Before posterior infradiaphragmatic bilateral resection of the splanchnic nerves and bilateral removal of the first lumbar ganglions, voluntary change to the upright from the horizontal position in six patients who had essential hypertension caused an average decrease of 9 mm. in the systolic blood pressure and an average increase of 8.4 mm in the diastolic blood pressure. The cardiac rate increased an average of 11.8 beats per minute. Following operation, assumption of the upright position produced an average decrease of 9.1 mm. in the systolic blood pressure and an average increase of 3.2 mm. in the diastolic blood pressure. The cardiac rate increased an average of 12.3 beats per minute. Voluntary change from the horizontal to the upright position by twenty-six patients, after ventral rhizotomy, caused varied results according to the extensiveness of denervation. Before operation, assumption of the upright position by one patient caused no change in the systolic blood pressure and an increase of 10 mm. of mercury in the diastolic blood pressure. The heart rate increased 22 beats per minute. This patient was subjected to ventral rhizotomy from the eleventh thoracic to the second lumbar, inclusive. Following operation, assumption of the upright position produced a decrease of 15 mm. in the systolic blood pressure and a decrease of 5 mm. in the diastolic blood pressure. The cardiac rate was unchanged. Before operation, assumption of the upright position by seven patients who had essential hypertension caused an average decrease of 21.4 mm. of mercury in the systolic blood pressure and an average decrease of 3.9 mm. in the diastolic blood pressure. The average cardiac rate was increased 18.9 beats per minute. These patients were subjected to ventral rhizotomy from the sixth thoracic to the second lumbar, inclusive. Following operation, assumption of the upright position produced an average decrease in the systolic blood pressure of 49.8 mm. and an average decrease of 21.9 mm. in the diastolic blood pressure. The heart rate increased an average of 29.6 beats per minute. Rhizotomy between these two levels gave results almost in proportion to the extensiveness of the sympathetic denervation. Before extensive bilateral splanchnic resection, partial resection of the celiac plexus and bilateral partial resection of the suprarenal glands, with bilateral removal of the first and second lumbar ganglions and the intervening trunks, assumption of the upright position by twelve patients who had essential hypertension produced no change in the systolic blood pressure and an average increase in the diastolic blood pressure of 5.3 mm. The pulse rate increased an average of 12 beats per minute. Following operation, assumption of the upright position produced an average decrease of 21.4 mm. in the systolic blood pressure and an average decrease of 10.5 mm. in the diastolic blood pressure. The pulse rate increased an average of 32.9 beats per minute. In both the group of cases in which extensive rhizotomy was performed, and in this group, the decrease of 21.4 mm. caused by posture was only about one-third as great as the total decrease caused by a combination of operation and posture. It would seem, therefore, that the lowered blood pressures following these surgical procedures are ascribable one-third to an introduced postural effect and two-thirds to the effects of the operations themselves. Finally, significant decreases in blood pressure of patients who had essential hypertension, particularly when they were in the upright position, were not produced by surgical methods except when extensive abdominal sympathetic denervation was effected. When less radical operations were performed, the magnitude of the decrease seemed roughly proportional to the extent of the denervation.