The role of the pressure in the endotracheal tube cuff in the development of iatrogenic tracheal injuries

Abstract

Background. The endotracheal tube insertion, which is a veritable patient care procedure, carries risks and possible adverse effects. Such complications vary in severity and range from mild symptoms such as sore throat or cough, which are often considered normal post-intubation events, to severe damage, including damage to the vocal cords, trachea, malacia, and fistula formation. A critical factor influencing the manifestation of these complications is the pressure exerted by the endotracheal tube cuff on the trachea. The purpose was to study the influence of high pressure of the intubation tube cuff on the incidence and severity of complications in an in vivo model. Materials and methods. A total of 12 rabbits were studied and divided into three groups according to target cuff pressure: 30, 50, and 100 cm H2O. Sevoflurane was used to maintain anesthesia, monitoring of vital functions included heart rate, pulse oximetry, capnography, and electrocardiography. Intubation was performed after induction with ketamine and administration of relaxants, and cuff pressure was measured with a mechanical manometer. The duration of pressure exposure was 20 minutes for each group, then the degree of tracheal damage was assessed by autopsy. Results. Increasing pressure generally leads to an increased risk of injury. In the third group (pressure of 100 cm H2O), all subjects had damage to the trachea, in 75 % of cases, it was a complete tracheal rupture. However, the dependence on pressure is not unambiguous for all types of injuries: the frequency of pneumothorax does not correlate directionally with the incidence of iatrogenic injuries and does not increase proportionally to pressure. So, for example, subcutaneous emphysema developed only in a third of cases of tracheal rupture. This emphasizes possible difficulties in timely diagnosis of this type of complications. Conclusions. The work highlights the risks associated with endotracheal intubation and emphasizes the need to maintain recommended practices and individual approach to each case. The most severe damage was observed at a pressure of 100 cm H2O, while at a pressure of 30 cm H2O, a smaller proportion of rabbits showed signs of damage.