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One-lung ventilation (OLV) is necessary for selected surgical settings and medical conditions. Different methods have been described and used to isolate 1 lung, including the double-lumen endotracheal tube (DLT) and a variety of bronchial blockers (BBs). This selection is often based on the preferences and experiences of the anesthesiologist and surgeon. Complications associated with OLV isolation tubes have been previously described, but complications specifically associated with the Cohen BB (CBB) (Cook Medical, Bloomington, IN) have not been investigated. The purpose of this retrospective review was to determine the incidence of vocal cord injury, tracheobronchial injury, and hoarseness in adult patients who underwent OLV with the CBB.
We reviewed electronic anesthesia records, operative dictation, and inpatient progress notes to collect information about vocal cord injury, bronchial injury, hoarseness, and sore throat for adults who underwent surgical and diagnostic procedures requiring OLV. Secondary endpoints were types of surgical procedures, degree of difficulty with orotracheal intubation, ability of the patient to tolerate extubation in the operating room, and whether the thoracic surgeon deemed the lung separation adequate. P<0.05 was considered significant.
Of 130 patients, 113 underwent OLV with a CBB, and 17 patients underwent OLV with a DLT. The thoracic surgeon deemed the lung isolation adequate in all cases. Airway injury occurred in 2 patients with a CBB and none with a DLT (P=0.86). Both airway injuries were attributed to surgical technique. Two cases of postoperative hoarseness occurred in the CBB group (P=0.86). One injury was attributed to vagus nerve transection, and the other injury was diagnosed as vocal cord paralysis of unknown etiology. In 1 case, orotracheal intubation with a DLT was unsuccessful because of intubation difficulty and required conversion to a regular endotracheal tube and CBB for successful lung isolation.
This study demonstrates that the use of CBB can be successful in a wide variety of thoracic operations, has minimal complications, eliminates the need for tracheal tube exchange when postoperative mechanical ventilation is required, and effectively isolates the lungs of critically ill patients.
Numerous clinical indications for one-lung ventilation (OLV) exist.1-5 Satisfactory OLV can be achieved via a double-lumen tube (DLT) or a bronchial blocker (BB). Certain clinical situations, such as lung lavage for severe pulmonary alveolar proteinosis, require the use of a DLT,1 but often the method of OLV is left to the preference and experience of the anesthesiologist in consultation with the surgeon. Although DLTs are more popular, the use of BBs is increasing.6,7
BBs offer benefits over DLTs. For example, a BB can be quickly inserted through an established single-lumen tube (SLT) during surgery,6 avoiding the technical challenges associated with insertion of the large and, at times, awkward DLT.8,9 Most thoracic procedures require preoperative bronchoscopy that cannot be performed through a DLT and would otherwise require a second reintubation of the trachea. During esophagectomy, the blocker is employed during the thoracic portion of the surgical procedure and is then removed for the abdominal component. The smaller profile of the SLT makes surgical dissection of the airway and esophagus easier and safer.10 Moreover, in difficult airways, the BB allows SLT placement using a variety of techniques not compatible with the DLT.7,11-13 The use of the BB also avoids postoperative orotracheal tube exchange if postoperative ventilation is required. Furthermore, continuous intraoperative observation of the blocker position in relationship to the airway anatomy is possible with a fiberscope placed above the carina, which is not possible with the DLT.
Once the anesthesiologist has decided to use a BB, many different models are available. The first tool specifically designed for bronchial blockade was the Univent torque control blocker (LMA Vitaid, Lewiston, NY) introduced in 1982.14 Over the past 20 years, several new, specialized orotracheal tubes have been introduced. The Cohen BB (CBB; Cook Medical, Bloomington, IN) facilitates placement into either the left or right mainstem bronchus by way of a steerable tip that can be easily maneuvered into place with a control wheel (Figure).15 This technique is novel and less cumbersome compared to other methods used to facilitate BB placement.16-18
Previous studies comparing the BB and the DLT have focused on the quality of lung isolation, time to lung collapse, malpositioning, and airway injury; the results of those studies have varied.17,19-24 One prospective study observed a reduced incidence of hoarseness, sore throat, and vocal cord injuries with the Arndt BB (Cook Medical) compared to the DLT.20 However, airway complications associated with the CBB have not been investigated. The purpose of this retrospective review was to determine the incidence of vocal cord injury, bronchial injury, hoarseness, and sore throat in adult patients who underwent general anesthesia via the CBB.
After receiving institutional review board approval, we performed a retrospective review of charts from January through December 2009. All cases were performed by the same thoracic surgeon. Records were screened to include adults (age >17 years) undergoing surgical and diagnostic procedures that required OLV. We excluded patients if they had a history of previous airway injury or if the trachea was intubated with an orotracheal or tracheostomy tube at the time of surgery. Airway management and placement of either the DLT or BB were performed by either an attending anesthesiologist or an anesthesia resident. Residents performing the procedure were closely supervised by the attending anesthesiologist.
Data were collected from the electronic anesthesia record (DocuSys Anesthesia, Merge Healthcare, Chicago, IL), operative dictation, and inpatient progress notes (Horizon Patient Folder, Merge Healthcare). The primary endpoints of the study were the incidence of vocal cord injury, bronchial injury, hoarseness, and sore throat. Secondary endpoints were the types of surgical procedures, degree of difficulty with orotracheal intubation, ability of the patient to tolerate extubation in the operating room, and whether the thoracic surgeon involved in all the cases deemed the lung isolation adequate. Categorical variables were expressed as percentages, and differences between the groups were assessed using chi-square or Fisher exact tests. Continuous variables with nonskewed distributions were expressed as mean and standard deviation, and differences between groups were assessed using the Student t test. Continuous variables with skewed distributions were expressed as median and interquartile range, and differences between groups were assessed by the Wilcoxon rank sum test. P values <0.05 were defined as statistically significant.
We included 130 patients in the study, dividing them into 2 groups. The CBB group had 113 patients (64 had right-sided isolation; 49 had left-sided isolation), and the DLT group had 17 patients (all left-sided DLTs). Demographics and findings are presented in the Table. The difference in the ratio of women to men in the CBB group as opposed to the DLT group was statistically significant. Airway injury occurred in 2 patients with a CBB but none of the patients with a DLT (P=0.86). The operative reports attributed both airway injuries to surgical technique. Two cases of postoperative hoarseness occurred in the BB group (P=0.86): One injury was attributed to vagus nerve transection, and the other injury was diagnosed as vocal cord paralysis of unknown etiology. The thoracic surgeon deemed the lung isolation adequate in all cases regardless of the method used to achieve OLV. However, we found a highly significant incidence of the DLT being exchanged for a conventional SLT for postoperative mechanical ventilation in cases when a DLT was initially used for lung isolation (P<0.0001). In 1 case, orotracheal intubation with a DLT was unsuccessful because of airway difficulty; an SLT was substituted for orotracheal intubation, and a BB was used for successful lung isolation. With regard to the other secondary endpoints of this study, we found no significant differences.
In this retrospective review, we compared several aspects of BB and DLT use, focusing on the incidence of airway complications. We found no significant difference between the 2 devices with regard to airway complications, a distinction Knoll et al22 observed in a previous study. Although Knoll et al22 reported few airway complications, significantly more tube exchanges were made when the DLT was used. We did not observe difficulty with exchanging a DLT with an SLT for postoperative mechanical ventilation, but others have reported that such exchanges involve suboptimal reintubation conditions and constitute a risk factor for postoperative airway complications.18
For all of our patients, the thoracic surgeon deemed the lung isolation adequate. External tracheal manipulation by the thoracic surgeon facilitated the success of lung isolation during CBB placement but may have played a role in postoperative hoarseness rates. Familiarity with BBs and facility with their placement are essential skills for anesthesiologists, especially in cases requiring OLV, in which BBs have been shown to have an advantage over DLTs. These cases include patients who are critically ill and intubated, who have an established tracheostomy, who are known to have difficult airways, or who may require nasotracheal intubation.7,8,11,25-29
One obvious limitation of this study is the retrospective design. Although detailed perioperative notes in the electronic records by the thoracic surgeon and the anesthesiologists lessen the limitations of retrospective chart reviews, this type of review may miss complications. Another possible limitation is the development of acute, transient, postoperative hoarseness that may not have been fully documented, suggesting that these complaints are minor. Additionally, technical problems related to BB and DLT insertion may have been omitted from the electronic anesthesia record, introducing clinical bias. We consider this possibility unlikely because the clinical team involved was facile with both techniques. Following completion of the procedure, the surgeon qualitatively described the adequacy of OLV. Moreover, no intraoperative failure of either technique was noted in the surgical or anesthesia records.
This study clearly demonstrates that CBB can be successfully used in a wide variety of thoracic operations, has minimal complications, eliminates the need for tracheal tube exchange, and provides the ability to effectively isolate lungs in critically ill patients, patients with difficult airways, or patients with tracheostomies, which are all known limitations of DLTs.
1Dr Abbas is now with the Department of Thoracic Surgery at Temple University Hospital and the Department of Surgery at Temple University School of Medicine, Philadelphia, PA.
The authors have no financial or proprietary interest in the subject matter of this article.
This article meets the Accreditation Council for Graduate Medical Education and the American Board of Medical Specialties Maintenance of Certification competencies for Patient Care and Medical Knowledge.