CONTROL DEL RUIDO

Despite widespread adoption of percutaneous techniques from the late 1980s onwards the outcomes, particularly long term ones, when compared to surgical tracheostomy and amongst the percutaneous techniques themselves were the subject of some discussion and debate.

1.8.1 Percutaneous tracheostomy versus surgical tracheostomy

The outcomes of percutaneous techniques compared to surgical tracheostomy have been the subject of three systematic reviews dating from 2006 – 2007. In the first such

review, Delaney evaluated randomised controlled trials comparing surgical tracheostomies with any percutaneous technique in the critical care setting51. He identified seventeen trials, including 1212 patients, the commonest percutaneous procedure evaluated being the original Ciaglia technique40_{. The principal findings}

were equivalence for bleeding, major short and long-term complications with a

significant reduction in stomal infections for the percutaneous procedures. Oliver later identified fourteen prospective trials (of which eight were randomised controlled trials) comparing surgical tracheostomy with a percutaneous technique performed in the critical care unit or the operating theatre52. They found no difference in major complications but a greater incidence of minor complications with percutaneous techniques along with a greater incidence of early complications for percutaneous techniques when compared to surgical tracheostomy performed at the bedside.

Higgins53 assessed fifteen randomised controlled trials (incorporating 973 patients) all but two of which  were  incorporated  in  Delaney’s  review51. They found percutaneous techniques resulted in fewer wound infections and cosmetic problems with no

difference in major complications. When pooled complications were analysed they found in favour of the percutaneous procedures.

1.8.2 Percutaneous versus percutaneous procedures

For many years there appears to be an assumption of equivalence across the

percutaneous techniques described. In an attempt to address this Cabrini undertook a systematic review of randomised controlled trials comparing two or more

percutaneous techniques54. They identified thirteen trials, incorporating 1030 patients, the most studied techniques being the original Ciaglia multiple dilator method, guide- wire dilating forceps and the single tapered dilator. They found that the Ciaglia and single tapered dilator techniques appeared to have the fewest complications. There

appeared to be an increase in minor complications with the guide-wire dilating forceps along with higher failure rates for both trans-laryngeal and rotational dilator techniques (PercuTwist®). They expressed some surprise at the paucity of randomised controlled trials when considering how widespread the use of percutaneous

tracheostomy has become. Overall it was felt that the most reliable technique for safety and success was the single tapered dilator. In a later review Cabrini also assessed the complication rates of the two most commonly used percutaneous techniques, the single tapered dilator and guide wire dilating forceps55. Having identified five eligible randomised controlled trials comprising 363 patients they concluded that the guide wire dilating forceps technique is associated with a higher incidence of intra-procedural bleeding and technical difficulties when compared with the single tapered dilator. There were no differences in mid and long-term outcomes. After many centuries of evolving surgical approaches along with advances in our knowledge of physiology and anatomy, percutaneous procedures have become established as the predominant tracheostomy techniques within the critical care setting. Complication rates across the various techniques appear to be at least as low as those achieved with surgical tracheostomies. It is possible that the single tapered dilator method is now the most frequently used procedure with the lowest associated complication rate. However, the paucity of data when comparing percutaneous procedures, particularly when considering long-term outcomes, is somewhat

surprising. It is clear, at present, that equivalence between procedures in this respect has not been fully established.

The meta-analyses described above have included only randomised controlled trials (RCTs)51,53. The only exception to this was the analysis by Oliver which also included

previous analyses comprised 346 patients56. It is perhaps unsurprising, therefore, that none of the previous meta-analyses have reported differences in late complication rates. The exact incidence of long term complications following tracheostomy

procedures in the critically ill is difficult to quantify due to the associated mortality of critical illness, the sub-clinical nature of many tracheal stenoses and the difficulty maintaining follow up of these cohorts. Given this associated morbidity and the cost associated with the management of TS a clearer picture of the risk associated with each tracheostomy technique performed within the critical care setting is required. 1.9 Aims

 To determine the utility of adjunctive techniques (bronchoscopy & ultrasound scanning) in reducing complications of percutaneous tracheostomies

percutaneous tracheostomy technique and hence determine the safest percutaneous technique

 To determine the incidence of common early and late complications and outcomes of PDT techniques in relation to surgical tracheostomy.

 To determine the relative indices of early and late complications in relation to percutaneous tracheostomy technique and hence determine the safest

percutaneous technique

 To determine the role of early complications that may be postulated to play a part in the genesis of the late complications of tracheal stenosis, tracheo- innominate artery fistula and tracheo-oesophageal fistula

Chapter 2