Comparison of left 4th and 5th intercostal space thoracotomy for open-chest cardiopulmonary resuscitation in dogs

Abstract

Open-chest cardiopulmonary resuscitation (OC-CPR) is indicated in certain cardiopulmonary arrest situations such as thoracic trauma. Laboratory research and clinical studies in human medicine have established the superiority of OC-CPR compared to closed-chest cardiopulmonary resuscitation (CC-CPR) with regard to cardiac output, aortic blood pressure, blood flow, and perfusion. Despite this demonstrated superiority, the technique for OC-CPR has not been described in detail in the veterinary clinical literature. The most convenient incision for performing OC-CPR is a left intercostal thoracotomy. Literature most commonly describes a 4th or 5th intercostal space (ICS) thoracotomy for performing OC-CPR in dogs. No studies to date have been performed to compare the two approaches. The goal of this study was to evaluate whether lateral thoracotomies through the 5th ICS should be recommended over those performed through the 4th ICS for canine OC-CPR. We hypothesized that access to the heart would be more convenient through the 5th ICS, and the 4th ICS would not provide appropriate access for all the procedures involved in performing OC-CPR. Left lateral thoracotomies were performed on twelve canine cadavers, six through the 4th ICS and six through the 5th ICS. Six parameters (ease of grasping phrenicopericardial ligament, ease of pericardial incision, ease of aortic access, ease of achieving appropriate hand position, ease of application of Rumel tourniquet, and ease of proper placement of defibrillator paddles) involved in performing OC-CPR were assessed by three evaluators. The results indicated that either 4th or 5th ICS thoracotomy may provide adequate access to intrathoracic structures pertinent for performing OC-CPR in dogs weighing approximating 20 kg, but the 5th ICS was found to be better for most manipulations.