Wednesday, January 8, 2014
By Jay B. Brodsky, MD
Every anesthesiologist must be able to selectively isolate and collapse a lung when requested to do so. Excellent operative conditions can be achieved with either a bronchial blocker or with a double-lumen tube
Jay B. Brodsky, M.D. Professor, Department of Anesthesiology, Stanford University School of Medicine, Stanford, CA, 94305, USA
All intra-thoracic surgical procedures can benefit from a “quiet” operative field. Therefore, every anesthesiologist must be able to selectively isolate and collapse a lung when requested to do so. Lung collapse can be accomplished with either a bronchial blocker (BB) or with a double-lumen tube (DLT). Both are safe and when accurately placed, both can provide excellent operative conditions.
Placement of a BB has always required bronchoscopy, either with a rigid or fiberoptic bronchoscope (FOB). A poorly positioned BB will fail to isolate the operated lung and/or will obstruct ventilation to both lungs. In contrast, DLTs, which have been used since the 1950s, were originally placed “blindly” using only clinical signs. The introduction of fiberoptic bronchoscopy in the 1980s greatly improved the safety and reliability of DLT placement.(1)
Although reusable FOBs have been widely available for decades, I have taught DLT placement using clinical signs alone.(2) My reasoning has been that a clean, functioning pediatric FOB may not always be readily available, especially during an emergency. Many institutions own a limited number of these scopes, and some of the inventory may be damaged and out for repair. Not only is it expensive to repair these scopes, but unless the scope is replaced immediately the number of available FOBs in any institution will be further limited until the repaired FOB is returned. Therefore, if an anesthesiologist relied entirely on bronchoscopy to use a DLT, there will be times when the surgical procedure would have to be delayed or even cancelled if no FOB could be found. In addition a hospital may have not have a FOB thin enough for some of the smaller DLTs. Also, if the FOB does not have appropriate suctioning capabilities, blood or mucus can obstruct the endoscopist’s ability to identify the carina or visualize the blue bronchial cuff in order to accurately place the DLT. Although fiberoptic bronchoscopy is certainly the safest and most accurate means of confirming DLT and BB placement, until very recently the availability of an appropriate size FOB at the time it was needed could not be guaranteed.
The introduction of the aScope 3 and the aScope 3 Slim FOBs into clinical practice has answered many of my concerns. A FOB can now always be available when needed so a procedure need not be cancelled or delayed. An aScope can remain with the patient during and even after the procedure so it will always be there and ready for use should it be needed. The suction channels of the aScope 3 are more than adequate for effective pulmonary toilet both during and after the anesthetic.
During thoracic surgery prior to placement of a BB or DLT, the anesthesiologist should examine the patient’s airway with a FOB for anatomic variation (eg tracheal bronchus), airway pathology, upper airway distortion, intrinsic obstruction and/or extrinsic compression.(3)
BBs are inserted through an endotracheal tube placed orally, nasally, or even via a tracheostomy. A FOB can assist in the actual intubation of the airway in situations when direct or video-laryngoscopy either fails or cannot be used. A FOB is then used as a guide to enter the appropriate bronchus over which a wire loop of the BB is advanced (Arndt® BB), and/or to position the blocker balloon in the bronchus under direct vision (Cohen® BB, Uniblocker®). The aScope 3 has a 5.0 mm outside diameter (o.d.) so it will fit any adult size endotracheal tube being used with a BB.
A FOB (or a video-laryngoscope) can also be used intubate the trachea with a DLT, especially if a difficult airway is anticipated or encountered. Alternately, a FOB can be used to first intubate the trachea with an endotracheal tube, and then that tube can be exchanged for a DLT over an airway exchange catheter. Once the airway has been successfully intubated, a FOB in the bronchial lumen can then be used as a stylet to advance the DLT into the appropriate bronchus. This technique is especially useful when the upper airway anatomy is distorted and “blind” advancement of the DLT into the bronchus is difficult.
Once the bronchial lumen is in the bronchus the correct placement of the DLT must be confirmed while the patient is supine. The FOB is first advanced down the tracheal lumen. There should be an unobstructed view of the non-intubated main-stem bronchus. All plastic DLT bronchial cuffs are colored blue for easy visualization. A rim of blue from the bronchial cuff should be visible just below the carina in the intubated bronchus. The aScope 3 Slim has a 3.8 mm o.d. and will fit the lumens of 37 Fr or larger plastic DLTs. If portions of the bronchial cuff are visible above the carina, especially if the cuff is partially obstructing the view of the non-intubated main-stem bronchus, both the tracheal and bronchial cuffs should be deflated and the tube should be advanced further into the bronchus under direct FOB guidance.
DLT position often changes while turning the patient for surgery. Once the patient is placed in the lateral position a FOB must again be used to re-confirm DLT placement. If the bronchial cuff is no longer visible the tube can be slowly withdrawn under direct vision until a rim of blue cuff is seen. More often, the tube will have partially pulled out of the bronchus and will need to be re-advanced back into the bronchus. The final step for accurate DLT placement is to advance the FOB down the bronchial lumen to demonstrate a patent upper-lobe bronchus. This is especially important if a right-sided DLT has been used since orifice to the right-upper lobe bronchus is more easily obstructed than the orifice of the left-upper lobe bronchus.
DLT position can also change intra-operatively due to manipulation of the bronchus by the surgeon, and from changing the patient’s neck position. Fiberoptic bronchoscopy allows observation of DLT position at any time during the procedure, and will help if re-adjustments become necessary. A FOB can be used to examine the operated lung before the collapsed lung is re-expanded, and for pulmonary toilet both during and after the procedure prior to extubation of the trachea.
I believe the availability of disposable FOBs will greatly enhance the safe practice of lung isolation and selective collapse during thoracic surgery.
|ROLES FOR FIBEROPTIC BRONCHOSCOPY DURING THORACIC SURGERY
1. Slinger PD: Fiberoptic bronchoscopic positioning of double-lumen tubes. J Cardiothorac Anesth. 1989; 3: 486-96
2. Brodsky JB: Fiberoptic bronchoscopy need not be a routine part of double-lumen tube placement. Curr Opin Anaesthesiol. 2004; 17: 7-11.
3. Campos JH: Update on tracheobronchial anatomy and flexible fiberoptic bronchoscopy in thoracic anesthesia. Curr Opin Anaesthesiol 2009; 22: 4-10
Fiberoptic Bronchoscopy During Thoracic Surgery