Clinical value of a prophylactic minitracheostomy after esophagectomy: analysis in patients at high risk for postoperative pulmonary complications

In Japan, the standard surgical procedure for esophageal cancer is subtotal esophagectomy with extended lymph node dissection, which requires the skeletonization of the upper mediastinal structures. This procedure is highly invasive, with high morbidity and mortality rates [1, 2]. Postoperative pneumonia is the most serious complication after esophagectomy and is a major risk factor for in-hospital mortality [3]. Impairment of the swallowing function due to cervical lymph node dissection and vocal cord palsy resulting from para-laryngeal nerve lymph node dissection both cause pulmonary aspiration. The impairment of postoperative pulmonary function and postoperative chest pain induce difficulty in expectoration, which can lead to sputum retention and postoperative pneumonia.

Although bronchoscopic aspiration is typically performed for sputum retention, this procedure requires trained bronchoscopists; a significant delay often occurs from onset to treatment. Bronchoscopic aspiration places a large burden on patients. Local anesthetic administered to the mucous membranes of the pharynx, larynx, and trachea often induces the pulmonary aspiration of intraoral bacteria. However, a minitracheostomy allows nursing staff without specialized training to have immediate access to the bronchial tree. The introduction of a catheter into the trachea through the minitracheostomy typically evokes an effective cough that helps clear secretions.

Previous authors have reported that a prophylactic minitracheostomy (PMT) helps prevent postoperative pulmonary complications in patients who undergo pulmonary resection for lung cancer [4‐8]. However, given the limited number of available reports, the clinical value of a PMT is unclear in patients undergoing an esophagectomy. Since January 2009, we have used a PMT in patients at a high risk for postoperative pulmonary complications to decrease these complications. The aim of this study was to evaluate the clinical value of a PMT in patients undergoing an esophagectomy for esophageal cancer and to clarify the indications for a PMT.

Our results demonstrated that the incidence of postoperative pulmonary complications in high-risk patients (the PMT group) was at least equivalent to that in the standard-risk patients (the non-PMT group). A noteworthy observation was that no patient required re-intubation in the PMT group. A PMT may prevent an increase in the incidence of postoperative pneumonia and re-intubation in patients at high risk for pulmonary complications. Although no complications related to a PMT were reported in this study, severe complications associated with a minitracheostomy have been reported, such as membranous tracheal injury, bleeding from the anterior cervical vein, hoarseness, and obstructive subglottic granuloma after removal of a minitracheostomy tube [11‐13]. A minitracheostomy may prevent elevation of the larynx during swallowing and impair the swallowing function. Therefore, a PMT should be restricted to high-risk patients, and it is important to appropriately select patients requiring a PMT.

Regarding our PMT indications in this study, age, low pulmonary function, and vocal cord palsy were reported to be associated with postoperative pneumonia after esophagectomy [14, 15]. Aspiration of oral bacteria is commonly known to cause postoperative pneumonia [16]. Vocal cord palsy with a slit and reduced swallowing function with aspiration on the upper gastrointestinal image were therefore included as indications for a PMT. In patients with preoperative pneumonia including interstitial pneumonia, worsening of this condition due to an esophagectomy can be lethal; thus, preoperative pneumonia was also included as an indication for PMT.

A routine tracheostomy may be safer than a minitracheostomy when emergency airway management is needed. However, a tracheostomy leads to temporary voicelessness, which is stressful for patients and causes impairment of the swallowing function due to the restriction of the elevation movement of the larynx during swallowing. Moreover, a tracheostomy can occasionally cause severe complications such as recurrent laryngeal nerve injury, tracheoesophageal fistula, or tracheo-brachiocephalic artery fistula. We propose that a prophylactic tracheostomy is too invasive.

In this study, none of the 30 patients who received a PMT according to our indications required re-intubation, whereas 12 of the non-PMT patients required a DMT due to postoperative sputum retention, and three developed severe pneumonia and required re-intubation. A multivariate analysis revealed that FEV1.0% <70% and vocal cord palsy were independent risk factors related to a DMT. Therefore, the indications for a PMT should be expanded for such patients despite the presence of a slit between the vocal cords. After this analysis, we expanded the indications for a PMT.

Although we focused on pulmonary function and aspiration to define the indications for a PMT, the DMT group included patients with health problems other than pulmonary function, such as liver cirrhosis, heart failure, and walking difficulty. In the prospective randomized trial reported by Pramod et al. [6, 17], the indications for a PMT included ischemic heart disease and cerebrovascular disease, which are likely to be exacerbated by postoperative hypoxia. In their study, some patients developed acute myocardial infarction or cerebellar infarction secondary to sputum retention. In addition to pulmonary function and aspiration, other organ disorders, such as heart failure, ischemic heart disease, liver cirrhosis, cerebrovascular disease, and performance status should be considered for a PMT.

In the present study, 11 of the 12 patients with a DMT due to postoperative sputum retention developed postoperative pneumonia, and three patients progressed to severe pneumonia. These observations demonstrate that a DMT after postoperative sputum retention cannot prevent postoperative pneumonia. In patients with sputum retention, oral bacteria may have dripped into the bronchial tree gradually due to postoperative vocal cord palsy and an impairment of swallowing function immediately after extubation. Thus, when sputum retention occurs, a pulmonary infection may have already developed. It is therefore important to prophylactically perform a minitracheostomy.

Some limitations were associated with this study. First, this is a retrospective study with only a small number of patients. Second, most of our patients underwent cervical lymph node dissection which is not generally performed in western country. Cervical lymph node dissection was reported to increase the incidence of vocal cord palsy [1] and impair swallowing function [18], and may lead to the increase of the incidence of postoperative pneumonia. Therefore, our results do not apply to patients without cervical lymph node dissection, and it may be necessary to reconsider the indications for a PMT for patients without cervical lymph node dissection. Third, all study patients underwent an open thoracotomy. The incidence of pulmonary complication in open thoracotomy has been reported to be 12.5 to 39.66% [19]. The incidence of postoperative pneumonia in our study was 35.1%, and not particularly high, compared with open thoracotomy groups in the other studies. However, thoracoscopic esophagectomy has recently become popular and has been reported to reduce pulmonary complications compared to open thoracotomy [19‐21]. It may be necessary to reconsider the PMT indications also for patients receiving thoracoscopic esophagectomy. Fourth, because this study did not compare two groups with the same condition, no conclusive results can be drawn from this comparison. A prospective randomized study comparing a PMT group and a non-PMT group of patients at high risk for pulmonary complications is needed.

A PMT for patients at high risk for postoperative pulmonary complications may be effective for preventing an increase in the incidence of postoperative pneumonia and re-intubation. The indications for a PMT should be expanded for patients with mild obstructive respiratory disturbances or vocal cord palsy despite the presence of a slit between the vocal cords.