Pneumothorax Following Bougie-guided Intubation in a Difficult Airway: A Report of Two Cases.

Patients coming for atlantoaxial dislocation surgery represent a unique subset of difficult intubation. In addition to having restricted neck movements, excessive movements at the neck joint during intubation must be avoided to avoid further compression. In view of the anticipated difficult intubation, adjuncts or introducers may be required to aid intubation, the most commonly used being bougies. Complications are known to occur with the use of bougies but fortunately the incidences are far and few. The most dreaded of these is pneumothorax, secondary to trauma by the bougie. The use of an adult bougie for pediatric intubations could possibly increase the risk of the same. Here, we report two incidences of pneumothorax after bougie-guided intubation. Copyright:

Introduction

Bougies are included in international guidelines as adjuncts to difficult intubations and are a standard part of all difficult airway carts.[1] Although they are indisputably useful, they may be associated with their own share of complications, the most dreaded of them is pneumothorax following airway trauma. Here, we report two incidences of pneumothorax after bougie-guided intubation, which presented at different phases in the perioperative period.

Case 1

A 6-year-old boy, known case of atlantoaxial dislocation, was posted for C1-C2 lateral mass fixation. An adult bougie was used to insert a 5.5 cuffed Portex tube (Portex, Smith’s Medical India Private Ltd., Borivali, Mumbai, India) for a Cormack–Lehane (CL) grade 2b, after laryngoscopy with Macintosh blade (Macintosh Blade, Anaesthetics India Private Ltd., Goregaon, Mumbai, India) no. 2. Prone position was given after confirming bilateral equal air entry. The patient started desaturating and saturation dropped to 78%. Auscultation revealed a decreased air entry on the left side with wheeze. The FiO2 was made 100%, inhaled salbutamol and injectable hydrocortisone were given. The saturation improved to 88% but air entry did not improve on the left side. The patient became hypotensive (78/40 mm Hg). The patient was made supine and a check laryngoscopy was performed to confirm tube position. The tube was withdrawn slightly. Neither the air entry nor the saturation improved, and the hypotension was unresponsive to fluid boluses. On suspecting a pneumothorax, a chest radiograph was taken in the operation theatre with a fluoroscope. A large left-sided pneumothorax was seen, which was treated with intercostal drainage. The hemodynamics improved dramatically and saturation of 98% was attained. The surgery was abandoned. He was extubated after elective ventilation for 6h.

The patient was taken up for surgery 15 days later. Following a C-Mac-guided intubation, he had an uneventful intraoperative course.

Case 2

A 7-year-old boy, operated case of C1-C2 lateral mass fixation, was posted for a transoral odontoidectomy. A CL grade 2b was visualized, for which an adult bougie was used to railroad a 5.5 number cuffed Portex tube, after laryngoscopy with Macintosh blade no. 2. After the procedure started, persistently high airway pressures (20–25 mm Hg) were recorded. As the entry of air remained equal on both sides, the high pressure was attributed to surgical manipulation. At the end of surgery, air entry was found to be reduced on the right side. Postoperative chest radiograph confirmed the presence of a large pneumothorax, which was relieved by intercostal drainage. The patient was electively ventilated for 1 day in view of transoral surgery and presence of pneumothorax.

Discussion

Pneumothorax is a rare (<0.1%) but potentially lethal complication of mechanical ventilation.[2] Risk factors for the development of pneumothorax under anesthesia include underlying lung disease, surgical procedures in the thorax or lower neck, central venous access, brachial plexus blocks, and barotrauma due to intermittent positive pressure ventilation.[3] Trauma during intubation is an unusual but known cause of pneumothorax, the chances of which increase to 0.5%–7% during difficult intubations.[2]

In both our patients, other factors that could increase the risk of pneumothorax had been ruled out. Computerized tomography of the chest showed no underlying lung disease, central venous access had not been established, and though the peak airway pressures were higher than normal in patient 2, the plateau pressures remained less than 30 mm Hg, so barotrauma was also ruled out as a likely cause.[4]

Both, American Society of Anesthesiology and Difficult Airway Society guidelines recommend the use of introducers in the form of bougies or stylets to aid CL grade 2 or 3a intubations.[1] Our protocol is to use a bougie rather than a stylet. Bougies could be single use, multiuse, or those with the ability for ventilation (Frova). Conventionally, either the “hold up” or “tracheal click” signs are used to insert bougies. Marson et al.[5] elicited that the force exerted while eliciting a “hold up” on using an Eschmann bougie was equal to that required for perforating the airway, whereas it was five times than required when a Frova was used. The force exerted at the tip increases with an increase in the distance of the tip from teeth.[5] Abandoning the “hold up” sign altogether and measuring out the bougie before insertion may be the solution for preventing airway trauma. This being said, ventilating bougie has an obvious advantage in difficult airways, in allowing ventilation even if intubation is not possible.

The other problem we faced was an unavailability of a midsize bougie. The two sizes of Frova tube introducers commercially available, include the pediatric, which is 8Fr and 35cm long, usable for tube sizes three or more, and the adult one, 14Fr and 70cm long, usable for tube sizes six upward.[6] The question arises for midsize tubes, namely 5 and 5.5 mm. The length of the pediatric bougie is insufficient to railroad the larger tube [Figure 1]. Though the adult bougie provides a sufficient length, it is too large to be used with a 5-mm tube and a snug fit with a 5.5-mm tube, to a point of causing friction while the tube is being inserted or removed [Figure 2]. The Smith’s single use bougie is also 14Fr, and thus offers no advantage over the Frova for these tubes.[7]

Figure 1

Comparison of pediatric bougie on the left with the adult gum elastic bougie on the right, which shows an insufficient length of the former for railroading

Figure 2

End-on views depicting the fit of various bougies with a 5.5 mm cuffed endotracheal tube. (In clockwise fashion: pediatric, single use, Frova, and reusable adult gum elastic)

Airway exchange catheters are available in intermediate sizes,[6] and there are articles reporting their use for intubation with conduits such as Laryngeal Mask Airways or Cuffed Oro-Pharyngeal Airway.[8] However, they are floppy, cannot be used by themselves and are capable of causing airway trauma themselves.[9]

Conclusion

Our case report highlights the need for vigilance even when following international set protocols. While using a bougie, care must be taken to measure out the length of the bougie required for insertion. Eliciting the “hold up” sign for insertion should be abandoned. A difficult airway cart must have bougies of different sizes available to suit all age groups. Difficult intubation requiring intermediate-sized tubes will require other adjuncts till bougies of such sizes may be manufactured. Finally, a high index of suspicion must be kept toward aberrant perioperative behavior for prompt diagnosis and treatment of complications.

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Conflicts of interest

There are no conflicts of interest.