Death after percutaneous dilatational tracheostomy: a systematic review and analysis of risk factors

Since the introduction and widespread acceptance of percutaneous techniques in the intensive care unit (ICU) setting, the number of critically ill patients undergoing tracheostomy has increased in recent years [1, 2]. Given a predicted increase in the numbers of mechanically ventilated patients, a further increase in the number of tracheostomy procedures in the ICU is to be expected [1‐4].

The ideal timing of tracheostomy is still a subject of debate as there is no clear evidence that early tracheostomy improves relevant endpoints, such as duration of mechanical ventilation, length of ICU stay, and mortality [5]. Nevertheless, tracheostomy is being undertaken significantly earlier during ICU stay, as the intervention appears to be beneficial in terms of patient comfort, mobility, and reducing the requirement for sedation [1, 6]. Percutaneous dilatational tracheostomy (PDT) has gained wide acceptance and has become the procedure of choice for tracheostomy in critically ill patients worldwide [7]. However this procedure, just like surgical tracheostomy, is associated with major complications, including death. It is estimated that each year approximately 500 patients in the United States die or are permanently disabled because of a tracheostomy [8].

Three fatalities due to PDT in our department in recent years prompted us to perform this study. We aimed to analyze cases from the literature and from our own database to determine the incidence of lethal complications due to percutaneous tracheostomy, to reveal the causes of death, to identify risk factors and possible mechanisms for lethal complications, and finally to develop recommendations to further minimize the risks of complication.

The study was conducted and reported according to PRISMA guidelines [9].

We analyzed 71 cases of death due to PDT. The incidence of death related to PDT calculated from departmental data provided by corresponding authors was 0.17%, which is in line with the lethal complication rate in our own institution. The main reasons for the catastrophic events resulting in death were vascular injuries and airway complications. We found specific risk factors in 73.2% of patients, and 25.4% of patients had more than one risk factor. To the best of our knowledge this is the first systematic analysis of lethal complications due to PDT.

Gilbey et al. recently published a case series of fatal cases due to PDT and concluded that this event usually results from vascular injury [32]. However, their report included only seven cases, without providing further information about demographics, PDT technique, use of bronchoscopy or ultrasound.

Even after surgical tracheostomy, fatal complications can occur. In a survey of members of the American Academy of Otolaryngology, Head and Neck Surgery two-thirds of (mainly surgical) tracheostomy-related catastrophic events were reported to be mainly due to loss of airway or bleeding [8].

Tracheostomy-related hemorrhage was the most common cause of death in our study. Massive hemorrhage is a rare but devastating complication after any form of tracheostomy and usually originates from tracheoarterial fistula formation. The majority of cases occur within three days to six weeks of tracheostomy, and risk factors include pressure necrosis from high cuff pressure, mucosal trauma, malpositioned cannula tip, low tracheal incision, excessive neck movement, radiotherapy, or prolonged intubation [26]. We found such risk factors in 77.8% of these patients. In 29.6% of studied patients with fatal bleeding, performing the procedure without bronchoscopy was determined as a risk factor. In this group, placement of tracheostomy was too low in five patients, of which two had an aortic arch laceration. Coagulation dysfunction or platelet dysfunction were present in five patients. These were not deemed to be the primary cause of bleeding in two cases as these patients died from acute and sudden bleeding from specific blood vessels and without diffuse bleeding. Indeed, it has been shown previously, that even in severe thrombocytopenia, PDT can be safely performed after preprocedural correction [62].

A major risk factor seems to be a low tracheal incision, as was the case in five of twenty-seven patients with bleeding complications in our study. The site of puncture should ideally be selected between first and second or second and third tracheal rings [63]. In one study, the site of tracheal puncture was changed in 24% of patients as a result of prior ultrasound [64]. Furthermore, preprocedural ultrasound and clinical examination have been used to detect abnormal pretracheal vascular anatomy. Therefore, several authors recommend ultrasound to improve the safety of PDT [64‐67].

The second most frequent cause of death was airway complications. The tracheal cannula was placed outside the tracheal lumen in three cases. Of note, in all of these cases bronchoscopic guidance was not used. Despite the lack of randomized controlled trials many authors think that the use of bronchoscopic guidance significantly increases the safety of PDT as it can guide correct placement of the introducer needle, the guidewire, and the cannula during the procedure [68, 69].

In a further 11 patients, the tracheal cannula accidentally dislocated postprocedurally. While the surgical approach allows easy reinsertion of the tracheal cannula, airway complications such as accidental decannulation or tube obstruction are well-described problems of the percutaneous technique [70]. Some researchers have proposed that fixing the tracheal cannula to the skin with sutures for the first postprocedural week may decrease cannula-related complications such as accidental decannulation and postoperative bleeding [71, 72].

In two of the eleven deaths (18.2%) due to posterior tracheal wall perforation, kinking of the guidewire was noticed after its removal during the procedure. Other researchers have postulated guidewire kinking as a possible mechanism for perforation of the posterior tracheal wall [73, 74]. Thus, kinking of the guidewire must be avoided and its occurrence should raise suspicion of potential injury to the posterior tracheal wall prompting further investigation.

To avoid complications, PDT should only be considered in selected patients without contraindications. Contraindications to PDT include anatomic distortion of the neck, the presence of a difficult airway, severe ARDS, uncorrectable coagulopathy, and the presence of an unstable cervical spine [68]. However, most of these contraindications are relative and also dependent on the skill of the operator. Of the ten cases (14.1%) in our study, where the performing team was deemed to be relatively inexperienced in the procedure, contraindications were also present in two patients (20.0%).

Because of the growing numbers of patients requiring ventilatory support, the frequency of tracheostomy in the ICU has increased over the last decades as has the number of PDT-related publications (Additional file 1). In addition, it is conceivable that after the introduction and widespread acceptance of percutaneous techniques, enthusiasm about the ease of performing this procedure at the bedside may have resulted in relative overuse by intensivists.

A general limitation of this systematic review is the possibility of under- or over-estimating the true incidence of PDT-related death. Accurate risk assessment in clinical medicine is most difficult when an event is rare and available evidence is based on self-reported data [75]. Additionally, concerning the topic of this study, there is sometimes considerable difficulty in differentiating whether an adverse event is due to being critically ill with a tracheostomy or whether it is a complication of the PDT procedure itself. However, in all cases included in this study, the authors of the original publications judged death to be most likely related to the PDT procedure itself. Calculated from departmental data provided by the corresponding authors - where we are confident of both the completeness of reporting and the denominator - the mortality rate from PDT was 0.17%. This is very much in line with the mortality rate of 0.16% reported in the largest study published to date [39] and the mortality rate of 0.16% in our own institution.

In our opinion, this first systemic analysis of the incidence and causes of PDT-related lethal complications adds important evidence to the literature and serves to remind clinicians about potentially life-threatening complications and to help them minimize risk factors by choosing suitable patients and safe procedural strategies.

In conclusion, PDTs, which are frequently performed in ICUs worldwide, are associated with an average mortality of one in every six hundred procedures. Major risk factors are present in a substantial proportion of these patients. To prevent severe complications, the results of this systematic review, several authors and professional guidelines suggest that the following measures may improve the safety of PDT: strict consideration of contraindications, bronchoscopic guidance during the entire procedure, performance by an experienced team, avoidance of a low tracheostomy puncture site and avoidance of guidewire kinking as well as the use of outer flange tracheal cannula sutures.