Surgical stress attenuates reflex heart rate response to hypotension

Abstract

Purpose: The baroreflex-mediated increase in heart rate (HR) in response to acute reduction of systolic blood pressure (SBP) was studied in order to assess whether the changes in arterial baroreflex sensitivity depend on the intensity of surgical stress, and location of visceral and somatic stimulation during surgery. Methods: Patients were divided into visceral stimulation groups [upper ( n --30) and lower (n = 30) abdominal surgery] and somatic stimulation groups [upper in = 25) and lower (n = 25) limbs, and chest wall (n = 25) surgery]. Acute hypotension as a baroreflex depressor test was induced by prostaglandin E~ (PGE,) 10 min before surgical incision (control) and during surgical manipulation under isoflurane-N20 anaesthesia or isoflurane-N20-fentanyl anaesthesia. Plasma level of ACTH was measured in an additional 40 patients who underwent upper abdominal surgery. Results: During upper abdominal surgery, the heart rate baroreflex sensitivity (AHR/ASBP) was depressed from -0.47 _+ 0.05 (control) to -0.01 _+ 0.04 (P < 0.05). The reflex heart rate baroreflex sensitivity remained unchanged and was similar among the remaining groups of patients. The concentration of ACTH increased from 12.5 -+ 1.0 (control) to 343 +-78.6 pg.ml-' (P < 0.05) with isoflurane-N20 anaesthesia but did not change with isoflu~ne-N20-fentanyl anaesthesia during upper abdominal surgery. Conclusion: Upper abdominal surgery is associated with the most stressful stimulation to attenuate heart rate baroreflex sensitivity. Integrity of the baroreflex can be preserved by adding opioids to supplement inhalation anaesthesia.Objectif : L~augmentation de la fr~quence cardiaque (FC) ~ m~diation baror~flexe en r~ponse ~ une diminution soudaine de la tension art&ielle systolique (-I-AS) a &~ ~tudi& dans le but d'~valuer si les changements de sensibilit~ art&ielle baror~flexe d~pendent de I'intensit~ du stress chirurgical et du si~ge de la stimulation visc&ale et somatique pendant la chirurgie. M&hode : Les patients ont ~t~ r~partis en diff6rents groupes : selon une stimulation visc&ale [chirurgie abdominale haute (n = 30) et basse ( n = 30)] et selon une stimulation somatique [chirurgie des membres sup6rieurs (n =25) et inf&ieurs (n = 25) ou chirurgie de la paroi thoracique (n = 25)]. Une hypotension soudaine, sous forme de test d~presseur baror~flexe, a ~t~ induite par la prostaglandine E, (PGE~) 10 rain avant I'incision chirurgicale (groupe t~moin) et pendant la manipulation chirurgicale sous anesth&ie avec isoflurane N20 ou sous anesth&ie avec isoflurane N20 et fentanyl. Le niveau plasmatique d'ACTH a ~t~ mesur~ chez 40 patients additionnels admis pour une chirurgie abdominale haute. R~sultats : Pendant la chirurgie abdominale haute, la sensibilit~ de la fr~quence cardiaque baror~flexe (AFC / ATAS) &ait abaiss~e de -0,47 _+ 0,05 (t~moin) ~ -0,01 + 0,04 (P < 0,05). La sensibilit~ r6flexe de la fr~quence cardiaque baror~flexe n'a pas chang~ et 6tait similaire parmi les autres groupes de patients. La concentration d'ACTH a augment~ de 12,5 -1,0 (t...

Endoscopic thoracic sympathectomy attenuates reflex tachycardia during head-up tilt in lightly anesthetized patients with essential plamar hyperhidrosis

“…Kohno and Taneyama [30] have recently shown that depression of the baroreflex control of HR by surgical stimuli differs markedly depending on the location of surgery. They found that upper abdominal surgery significantly depressed baroreflex function, but that surgery of the lower abdomen, extremities, or chest wall had no effect on this function.…”