Congenital Heart Surgery

Ghani MOA, Foster J, Shannon CN, Bichell DP. Association of chest tube position with phrenic nerve palsy after neonatal and infant cardiac surgery. J Thorac Cardiovas Surg. 2021 May;161(5):1618-1622.e1.   Commentary from Dr. Frederic Jacques (Quebec City, QC, Canada), chief section editor of Congenital Heart Surgery Journal Watch:  Screening Journals to create May 2021’s selection of congenital cardiac surgery papers, I found numerous interesting papers on ultra-specific topics. The reader is encouraged to look at this month’s list of abstracts as it contains insightful papers on the management of single ventricle patients, atrioventricular ventricular septal defect, tetralogy of Fallot, etc. Nevertheless, the topic I decided to feature is far less attractive, but so important: phrenic nerve palsy. This complication is relatively frequent (4%), has a major impact on patient’s clinical outcome, and is quite frustrating for the meticulous surgeons we all expect to be. Direct trauma to the phrenic nerves by both anesthetic and surgical manipulations are well recognized risk factors. Bichell and colleagues (Vanderbilt University, Nashville) postulated that pressure nerve damage could occur by indwelling chest tubes. The authors evaluated the effect of a strategy of avoiding chest tube positioning in proximity to the nerve within the apex of the right apical portion of the right pleural cavity.   All 531 operations performed under cardiopulmonary bypass in neonates and infants of less than 1-year of age by a single surgeon were assessed from January 2012 to June 2019. All chest tubes were 19 Fr Blake chest tubes connected to a Pleur-evac system. Positioning of the chest tube within the chest changed in September 2018. Before this hinge point, chest tubes were positioned far in the chest and looping apico-medially into the second intercostal space. After September 2018, this “danger zone” was avoid. Positioning of the tubes was assessed on chest roentgenograms by 3 blind examiners. Patients were divided into two groups according to the presence or absence of right diaphragm paralysis. The location of the tube (within or outside the danger zone) was compared to patient’s size at the time of surgery, the age, the dwelling time of the tube, the cardiopulmonary bypass time, the ventilation time, the length of stay in intensive care unit length of time and in hospital, the readmission rate and the 30-day mortality. Patients with phrenic palsy had a longer intubation time (20 vs. 3 days) and LOS (53 vs. 17 days). Fortunately, 30-day mortality was not affected. Of 5 variables considered in multivariable analyses, only chest tube position was significant for phrenic palsy. Avoiding the apical portion of the right pleural cavity was protective as no event occurred.   This paper is of great interest as diaphragm paralysis may affect all the spectrum of pediatric cardiac surgery. Having diaphragm paralysis may have catastrophic consequences on the management of single ventricle patients on whom stage 1 palliative strategies were recently performed. Secondary increased pulmonary vascular resistance in these patients may lead to instability and may require early diaphragmatic plication. On the other end of the spectrum, there is not much complication as frustrating as having a diaphragm paralysis after simpler surgeon such as isolated ventricular septal defect closure, to give an example. For all type of patients such complications seem avoidable and realizing that factors other than the intraoperative management may impact on diaphragmatic function is important. With the findings of this paper, every surgeon should beware the placement of chest tube within the right apical portion of the chest (and likely the left by extrapolation). Avoiding preventable complications is the goal for all surgeries and placing chest tubes in the apical portions of pleural cavities should likely be considered an error from now on.