EComment. Massive pulmonary air embolism during pacemaker implantation: better preoperative exams?

Abstract

Pacemaker implantation due to sick sinus node syndrome is a routine procedure nowadays. Despite the rather small number of complications, the most challenging cases are associated with pneumothorax and infection. Air embolism is a rare complication of insertion or removal of central venous catheters, but can lead to cardiac arrhythmias, obstruction of the pulmonary outflow tract, acute cor pulmonale and asystole, depending on its volume. Furthermore, when moving to arterial circulation via patent foramen ovale, it can lead to ischaemic events. The reasons of such a paradoxical complication could be an inadequate examination of respiratory function during preoperative survey, catheters without haemostatic valve or central venous catheter procedures include large-calibre catheters, iatrogenic factors, low central venous pressure, negative intrathoracic pressure and inability for the patient to lie in a supine or Trendelenberg position. Because of the lack of specific signs and symptoms of venous air embolism, a high index of suspicion is necessary to establish the diagnosis. The primary physiological effects of air embolism are elevated pulmonary artery pressures, increased ventilation-perfusion inhomogeneity, and right ventricular failure. The degree of physiological impairment depends on the volume of gas entrained, the rate of entrainment, the type of gas entrained, and the position of the patient when the embolism occurs. This case report of repeated massive pulmonary air embolism during pacemaker implantation by Wu and Chen is very important for clinicians [1]. The reasons are that there are not so many similar cases, and that the procedure is carried out under the local anaesthesia with no need for sedation and invasive lung ventilation. Some specific causes and symptoms were observed by Ninio and Hii [2] and Turgeman et al. [3], but general principles of early diagnostic or even prevention have not yet been identified. Treatment stategies vary from putting the patient in the Trendelenburg position, 100% oxygen flow or hyperbaric oxygen treatment, in order to reduce the volume of the embolus by diffusion of oxygen to the plasma, haemodynamic support, adequate supplementation of inspired oxygen and prevention of further air entry into the circulation [4]. Conflict of interest: none declared