Electrophysiological evaluation of phrenic nerve injury during cardiac surgery – a prospective, controlled, clinical study

Abstract

BackgroundAccording to some reports, left hemidiaphragmatic paralysis due to phrenic nerve injury may occur following cardiac surgery. The purpose of this study was to document the effects on phrenic nerve injury of whole body hypothermia, use of ice-slush around the heart and mammary artery harvesting.MethodsElectrophysiology of phrenic nerves was studied bilaterally in 78 subjects before and three weeks after cardiac or peripheral vascular surgery. In 49 patients, coronary artery bypass grafting (CABG) and heart valve replacement with moderate hypothermic (mean 28°C) cardiopulmonary bypass (CPB) were performed. In the other 29, CABG with beating heart was performed, or, in several cases, peripheral vascular surgery with normothermia.ResultsIn all patients, measurements of bilateral phrenic nerve function were within normal limits before surgery. Three weeks after surgery, left phrenic nerve function was absent in five patients in the CPB and hypothermia group (3 in CABG and 2 in valve replacement). No phrenic nerve dysfunction was observed after surgery in the CABG with beating heart (no CPB) or the peripheral vascular groups. Except in the five patients with left phrenic nerve paralysis, mean phrenic nerve conduction latency time (ms) and amplitude (mV) did not differ statistically before and after surgery in either group (p > 0.05).ConclusionsOur results indicate that CPB with hypothermia and local ice-slush application around the heart play a role in phrenic nerve injury following cardiac surgery. Furthermore, phrenic nerve injury during cardiac surgery occurred in 10.2 % of our patients (CABG with CPB plus valve surgery).

Right Phrenic Nerve Palsy Post Coronary Artery Bypass Grafting (CABG) without Harvesting Right Internal Mammary Artery (RIMA): A Rare and Unexpected Complication

“…This is in contrary to a study done by Kaufman and his coauthors, and another study by Canbaz [10][11][12], which has emphasized the need for early surgical intervention in such cases in the form of diaphragmatic plication or diaphragmatic pacing.…”

“…The literature dealing with phrenic nerve injury post CABG advocated that left phrenic nerve damage is much more frequent than right, and in the study by Canbaz et al, they found that in all the cases post CABG the injured nerves were the left ones [11]. However, both the left and right nerves have been equally exposed to cardiopulmonary bypass and systemic hypothermia, suggesting that the hypothermic cardiopulmonary bypass is not in itself the cause for the damage.…”

“…During cardiac surgeries, topical cooling is frequently oriented to the left ventricle, when we apply ice slush around the left ventricle and in to the left portion of the pericardial cavity. For this reason, the left phrenic nerve thermal injury is more frequent than the right phrenic nerve, which is frequently preserved from cold injury [2,6,9,11].…”

Can't Breath: a case of unilateral diaphragmatic paralysis post CABG

“…Its presentation can range in severity from being asymptomatic to acute respiratory failure 1,7 . There are a variety of treatments available to improve symptoms.…”

Hoarseness subsequent to cardiovascular surgery, intervention, maneuver and endotracheal intubation: The so-called iatrogenic Ortner’s (cardiovocal) syndrome

“…Dissection of the left internal mammary artery to its origin potentially jeopardizes the vagus nerve or its associated branches [12]. Injury from local cooling of the heart may be a possible etiology of hoarseness, but is more frequently associated with phrenic nerve palsy [60].…”