Improvement of Arterial Oxygen Saturation with Selective Lobar Bronchial Block During Hemorrhage in a Patient with Previous Contralateral Lobectomy

Abstract

A serious complication of one-lung ventilation (OLV) is hypoxemia [1]. One way to improve oxygenation during OLV is to apply continuous positive airway pressure (CPAP) to the nondependent lung [2]. If CPAP fails to improve oxygenation, the nondependent lung may need to be reexpanded, making surgery difficult or impossible. A new single-lumen endotracheal tube with enclosed bronchial blocker (Univent tube; Vitaid, Lewiston, NY) has the capability of collapsing selectively one lung either totally or partially, i.e., one lobe expanded while the rest collapsed, during OLV [3]. We know of no clinical reports on the use of this device as a lobar blocker of a single lung. We report a patient who had a previous contralateral lobectomy now being operated on for right lower lobectomy, where, during hemorrhage, selective blockade of the bronchus intermedius of the nondependent lung using a single-lumen endotracheal tube with enclosed bronchial blocker improved arterial oxygen saturation (SpO2) after CPAP failed, while permitting surgery to continue uninterrupted. Case Report A 78-yr-old, 70-kg female presented with a right lower lobe mass and was scheduled for right lower lobectomy. Prior to this hospitalization, she had received several general anesthetics for many operations, including aortic valve replacement, permanent pacemaker, and left lower lobectomy, all performed without complication. Her past medical history included smoking one pack of cigarettes per day for 40 yr. Pulmonary function tests prior to surgery were as follows: forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and carbon monoxide diffusing capacity (DLCO).Table 1After standard monitors were placed, glycopyrrolate (0.3 mg intravenously) was given, and anesthesia was induced with fentanyl 100 micro gram, etomidate 30 mg, and vecuronium bromide 8 mg intravenously followed by inhalation of isoflurane 1% and 99% oxygen. The trachea was intubated with a 7.5 mm internal diameter single-lumen endotracheal tube with a built-in bronchial blocker (Univent tube). A pediatric fiberoptic bronchoscope (FOB) was passed to identify carina, right main bronchus, and right upper bronchial orifice. The bronchial blocker was advanced into the right mainstem bronchus under direct vision, and left in place. An arterial catheter was placed. After the patient had been turned to the lateral decubitus position, the FOB was again passed to confirm the proper location of the bronchial blocker cuff. The bronchial cuff required 8 mL of air to seal and block the right mainstem bronchus. After surgery began, the right lung was collapsed entirely. With SpO2 at 99%, results of arterial blood gas analysis were: pHa 7.34, PaCO2 49 mm Hg, PaO2 294 mm Hg, base excess + 1 mEq/L, HCO3 27 mEq/L. Hematocrit was 37%. Twenty minutes after surgery began, bleeding was encountered. Arterial blood pressure after 500 mL of blood loss was 120/70 mm Hg, paced heart rate 70 bpm, but SpO2 decreased from 98% to 85%. Ventilation of the dependent lung was controlled at a rate of 16 breaths/min and tidal volume of 450 mL using 99% oxygen. Changes in tidal volume, rate, and peak respiratory pressure did not improve oxygenation. Reexpansion of the operated lung improved SpO2 to 98%. We were asked to collapse the lung entirely, to facilitate identification of the site and control the bleeding. FOB again demonstrated proper placement of the bronchial blocker. CPAP was initiated on the nondependent lung through the suction port of the bronchial blocker. Five centimeters H2 O was applied with some distention of the lung but no improvement in SpO2 (88%). Ten centimeters H2 O of airway pressure was applied, again without success. Blood loss at this point was 1 L and continuous, with a blood pressure of 120/60 mm Hg, paced heart rate 70 bpm. Colloid solution, 500 mL, was given during the initial bleeding along with dopamine (3 micro gram centered dot kg-1 centered dot min-1). After CPAP failed, using the FOB we advanced the bronchial blocker into the bronchus intermedius in order to bypass the right upper bronchus, which allowed us to ventilate the right upper lobe while collapsing the right middle and right lower lobes. The bronchial cuff was inflated with 4 mL of air after being seated in the bronchus intermedius. Direct observation of the surgical field showed ventilation of the right upper lobe, with total collapse of the middle and lower lobe. The surgeon found and corrected several bleeding sites once the selective partial collapse was achieved. SpO2 improved to 98% and remained between 98% and 100%. A tracing of the trends in SpO (2) is shown in Figure 1.Figure 1: Recording of the arterial oxygen saturation (SpO2) on the vertical axis. The horizontal axis indicates time. The arrows indicate: 1, one-lung ventilation (OLV); 2, bleeding + desaturation; 3, reexpansion of the right lung; 4, continuous positive airway pressure (CPAP) 5 cm H2 O; 5, CPAP 10 cm H2 O; 6, bleeding + desaturation; 7, application of lobar ventilation to right lung.As the right lower lobectomy was completed, arterial blood gases determined during selective partial lung collapse were: pHa 7.28, PaCO2 56 mm Hg, PaO2 360 mm Hg, base excess--0 mEq/L, HCO3 28 mEq/L. The dopamine infusion was discontinued, bronchial blocker deflated and withdrawn, the entire lung inflated, and the chest closed. At the conclusion of surgery the patient remained intubated using the single-lumen tube with bronchial blocker withdrawn. The patient was transported to the intensive care unit, where mechanically assisted ventilation was applied. She was tracheally extubated without complications 6 h later and recovered uneventfully. Discussion One lung ventilation is used to facilitate surgical exposure during surgery of the lung, aorta, or esophagus. A single-lumen endotracheal tube with an enclosed bronchial blocker can serve this purpose [4]. Ginsberg [5] reported the use of endobronchial blockade with a Fogarty catheter during OLV. In that report there is no mention of partial blockade of the nondependent lung. Cant et al. [6] reported a case where bronchial blockade was possible by using a Fogarty catheter in a child with a bronchopleural-cutaneous fistula. Hypoxemia is common during OLV. Factors that contribute to hypoxemia in the lateral decubitus position include reduced lung volume of the dependent lung, lung compression by the mediastinum, absorption atelectasis, and fluid transudate into the dependent lung. Assuming that cardiac output is normal after proper placement of the bronchial blocker, the first line treatment of hypoxemia and desaturation during OLV in the anesthetized subject is CPAP. An alternative to improve oxygenation is to reinflate the nondependent lung and ventilate with 100% oxygen, realizing that this manuver might disturb the surgical field. Benumof et al. [2] have shown that CPAP (up to 10 cm H2 O) in the nondependent lung improved oxygenation when the single lumen tube with bronchial blocker was used. In our case, with abnormal pulmonary function tests and absence of the left lower lobe, the patient could not tolerate OLV during hemorrhage and surgical repair. Because CPAP failed to improve saturation, we chose to ventilate the right upper lobe selectively, allowing the right middle and lower lobes to remain collapsed and allowing identification and repair of the bleeding sites by the surgeons. Because of the rapidly changing clinical situation we relied on pulse oximetry to assess oxygenation during anesthesia and OLV [7]. There is controversy concerning the most favorable method to perform OLV; either a single lumen tube with bronchial blocker or a double-lumen tube can be used for this purpose [3,8]. A single-lumen tube with bronchial blocker can be used to ventilate selectively lobes of the nondependent lung while collapse of the remaining lung is achieved. We believe this is a new technique to improve the difficult balance between need for surgical exposure versus oxygenation. In summary, we report a case where improving SpO2 was accomplished by selective, lobar collapse of the nondependent lung using a single-lumen endotracheal tube with an enclosed bronchial blocker.