Background

Percutaneous dilatational tracheostomy (PDT) is one of the most common bedside surgical procedures performed in critically ill adults, on intensive care units (ICUs), who require long‐term ventilation. PDT is associated with relevant life‐threatening complications: Cuff rupture or accidental extubation may lead to hypoxia, aspiration or loss of airway. Puncture of the oesophagus, or creating a false passage during dilatation or replacement of the tracheostomy tube, can lead to pneumothorax or emphysema. Wound infections may occur which can cause mediastinits, especially after creation of false passage or in early tracheotomized post‐sternotomy patients after cardiac surgery. During the procedure, the patient's airway can be secured with an endotracheal tube (ETT) or a laryngeal mask airway (LMA). This is an updated version of the review first published in 2014.
Objectives

To assess the safety and effectiveness of LMA versus ETT in critically ill adults undergoing PDT on the ICU.
Search methods

We searched the following databases to 9 January 2018: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase. We searched for reports of ongoing trials in the metaRegister of Controlled Trials (mRCT). We handsearched for relevant studies in conference proceedings of five relevant annual congresses. We contacted study authors and experts concerning unpublished data and ongoing trials. We searched for further relevant studies in the reference lists of all included trials and of relevant systematic reviews.
Selection criteria

We included randomized controlled trials (RCTs) that compared use of laryngeal mask airways versus endotracheal tubes in critically ill adults undergoing elective PDT in the ICU, without injuries to or diseases of the face or neck. We imposed no restrictions with regard to language, timing or technique of PDT performed.
Data collection and analysis

Two review authors independently assessed the eligibility and methodological quality of each study and carried out data extraction. Our primary outcomes were all‐cause mortality, procedure‐related mortality and tally of participants with one or more serious adverse events. Where possible, we combined homogeneous studies for meta‐analysis. We used Cochrane's 'Risk of bias' tool and used GRADE to assess the quality of evidence for key outcomes.
Main results

We included nine RCTs in this review involving 517 participants.

Studies had a high or unclear risk of bias. The main reason for this was low methodological quality or missing data, even after study authors were contacted. Study size was generally small, with a minimum of 40, and a maximum of 73 participants.

In one study (40 participants), three deaths in the LMA group and two deaths in the ETT group were reported, although none of the deaths were related to the procedure (very low‐quality evidence).

Five studies (281 participants) reported on procedure‐related deaths, stating that no procedure‐related death occurred at all (very low‐quality evidence).

It is uncertain whether there is a difference in the number of people experiencing one or more serious adverse event(s) between LMA and ETT (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.41 to 1.80; 467 participants, 8 studies, very low‐quality evidence).

The duration of the procedure may be shorter in the LMA group (mean difference (MD) ‐1.46 minutes, 95% CI ‐1.92 to ‐1.01 minutes; 6 studies, 324 participants, low‐quality evidence).

However failure of procedure, as allocated by randomization, requiring conversion to any other procedure, may be higher in the LMA group (RR 2.82, 95% CI 1.22 to 6.52; 8 studies, 439 participants, low‐quality evidence).

We did not find any clear evidence of a difference between ETT and LMA groups for all other outcomes. Only one study provided follow‐up data for late complications related to the intervention, showing no clear evidence of benefit for any treatment group.
Authors' conclusions

Evidence on the safety of LMA for PDT is too limited to allow conclusions to be drawn on either its efficacy or safety compared with ETT. Although the LMA procedure may shorten the period during which the airway is insecure, it may also lead to higher conversion rates. Also, late complications have not been investigated sufficiently. These results are primarily based on single‐centre trials with small sample sizes, and therefore the level of evidence remains low. Studies with low risk of bias focusing on late complications and relevant patient‐related outcomes are necessary for definitive conclusions on safety issues related to this procedure. The dependency of the successful placement of a LMA on the type of LMA used should also be further assessed.

There are two studies awaiting classification that may alter the conclusions once assessed.