Dawn P. Desiderio

The Effects of Endobronchial Cuff Inflation on Double-Lumen Endobronchial Tube Movement After Lateral Decubitus Positioning

OBJECT This study was designed to measure changes in tracheal and bronchial lumen distances from mainstem and secondary carina with lateral positioning, and to assess whether inflation of the endobronchial cuff before lateral positioning would further secure a double-lumen endobronchial tube (DLT) and reduce movement. DESIGN Prospective study. SETTING University-affiliated cancer center. PARTICIPANTS Fifty adult patients scheduled for elective thoracic surgical procedures requiring the placement of a left DLT. INTERVENTIONS Patients were sequentially assigned to either the endobronchial cuff-inflated group or the deflated group during lateral positioning. After induction of general anesthesia, a left polyvinylchloride (PVC) DLT was placed and the position confirmed. In the supine position, the distance from the tip of the tracheal lumen to main carina was measured using a fiberoptic bronchoscope (FOB) passed through the tracheal lumen, and the distance from the bronchial lumen to secondary carina was measured with the FOB passed through the bronchial lumen. The patients were then positioned laterally and a second set of measurements taken. Overall movement was determined by increases and decreases in tracheal and bronchial distances obtained by substracting supine values from lateral values. MEASUREMENTS AND MAIN RESULTS There was significant tracheal movement in 40 of 50 patients, with a mean of 0.92 +/- 1.0 cm. This was predominantly in the upward direction, as seen in 35 of 50 patients. There was significant bronchial movement in 37 of 50 patients, with a mean of 0.92 +/- 1.15 cm. Also, predominance in the upward direction was seen in 34 of 50 patients. CONCLUSIONS DLTs move with lateral positioning, regardless of endobronchial cuff inflation. The movement is predominantly in the upward direction. Therefore, fiberoptic visualization in the supine position should be used only to confirm that the endobronchial lumen is placed on the appropriate side and the cuff is at least 1 cm inside the left mainstem bronchus. Final positioning should always be verified in the lateral position.

Practice patterns in choice of left double-lumen tube size for thoracic surgery.

BACKGROUND:Some anesthesiologists choose smaller than body size-appropriate left sided double-lumen tubes (DLTs) (“down-size“) for lung isolation in an attempt to limit the risk of airway trauma. There are few data on the effects of DLT size on intraoperative outcome measures. METHODS:In 300 adults undergoing thoracic surgery requiring lung isolation, we conducted a prospective pilot study to evaluate whether the use of 35 FR DLT, regardless of gender and/or height (care standard of two investigators), was associated with a similar incidence of intraoperative hypoxemia, lung isolation failure, or need for DLT repositioning during surgery (noninferiority) than with the conventional goal of inserting the largest possible DLT (care standard of two other investigators). DLT insertion position was immediately confirmed with fiberoptic bronchoscopy after direct laryngoscopic placement and after lateral positioning. RESULTS:The combined incidence of transient hypoxemia, inadequate lung isolation, or need for DLT repositioning during surgery did not differ among patients receiving 35, 37, or 39 FR DLT, regardless of gender or height. Despite the high frequency of 35 FR DLT use, 2% of patients required further down-sizing due to the inability to introduce the DLT into the left mainstem bronchus or when no inflation of the bronchial cuff was needed for lung isolation. CONCLUSIONS:Under the conditions of this pilot study, the use of smaller than conventionally sized DLT was not associated with any differences in clinical intraoperative outcomes.

A clinical evaluation of pulse oximetry during thoracic surgery

To evaluate the utility of pulse oximetry for monitoring oxygenation during thoracic surgery, pulse oximeter oxygen saturation (SpO2) values from the Nellcor N-100 (Nellcor Inc, Haywood, CA) and Novametrix model 500 (Medical Systems Inc, Wallingford, CT) were compared with simultaneous arterial saturation values (SaO2) in 20 patients. A total of 255 matched observations were recorded, and the data were divided for statistical analysis into preinduction of anesthesia and postinduction groups. The preinduction group showed a good correlation between SpO2 and SaO2 values, with both pulse oximeters consistently overestimating the SaO2. However, once anesthesia was induced, there was no longer any correlation for either of the pulse oximeters versus simultaneous SaO2 values, although on average, the SpO2 values were significantly higher than the corresponding SaO2 values. It was concluded that pulse oximetry is useful in following trends of oxygenation in patients with preexisting lung pathology undergoing thoracic surgery, but it cannot replace arterial blood gas sampling for the intraoperative management of respiratory function.

Protective Lung Ventilation and Morbidity After Pulmonary Resection: A Propensity Score–matched Analysis

BACKGROUND: Protective lung ventilation (PLV) during one-lung ventilation (OLV) for thoracic surgery is frequently recommended to reduce pulmonary complications. However, limited outcome data exist on whether PLV use during OLV is associated with less clinically relevant pulmonary morbidity after lung resection. METHODS: Intraoperative data were prospectively collected in 1080 patients undergoing pulmonary resection with OLV, intentional crystalloid restriction, and mechanical ventilation to maintain inspiratory peak airway pressure <30 cm H2O. Other ventilator settings and all aspects of anesthetic management were at the discretion of the anesthesia care team. We defined PLV and non-PLV as <8 or ≥8 mL/kg (predicted body weight) mean tidal volume. The primary outcome was the occurrence of pneumonia and/or acute respiratory distress syndrome (ARDS). Propensity score matching was used to generate PLV and non-PLV groups with comparable characteristics. Associations between outcomes and PLV status were analyzed by exact logistic regression, with matching as cluster in the anatomic and nonanatomic lung resection cohorts. RESULTS: In the propensity score–matched analysis, the incidence of pneumonia and/or ARDS among patients who had an anatomic lung resection was 9/172 (5.2%) in the non-PLV compared to the PLV group 7/172 (4.1%; odds ratio, 1.29; 95% confidence interval, 0.48–3.45, P= .62). The incidence of pneumonia and/or ARDS in patients who underwent nonanatomic resection was 3/118 (2.5%) in the non-PLV compared to the PLV group, 1/118 (0.9%; odds ratio, 3.00; 95% confidence interval, 0.31–28.84, P= .34). CONCLUSIONS: In this prospective observational study, we found no differences in the incidence of pneumonia and/or ARDS between patients undergoing lung resection with tidal volumes <8 or ≥8 mL/kg. Our data suggest that when fluid restriction and peak airway pressures are limited, the clinical impact of PLV in this patient population is small. Future randomized trials are needed to better understand the benefits of a small tidal volume strategy during OLV on clinically important outcomes.