Management of Failed Conventional Tracheal Intubation
Multiple and prolonged conventional laryngoscopy (CL) and tracheal intubation attempts frequently lead to the development of progressive difficulties with face-mask ventilation and increase the risk for a cannot-ventilate and cannot-intubate situation (36, 44). Reliance on CL is a risk-enhancing behavior that predisposes patients to severe morbidity and occasionally to mortality. Therefore, the number of conventional tracheal intubation attempts and the time required should be limited. When the patient is placed in optimum position aligning the ear to the sternal notch (17), the appropriate laryngoscope type and size is used, and external laryngeal manipulation is exercised (7) and the laryngeal view is poor, attention should be early directed to an alternative to CL, using a laryngeal mask airway (LMA) to establish ventilation, or awakening the patient when feasible (2, 11, 22).
The French expert working group (10) and the American Society of Anesthesiologists task force (2) recommend not to exceed two conventional tracheal intubation attempts, while the German and the Italian expert working group (11, 43) limit CL to a maximum of three attempts. The British expert working group (32) allows CL with the same laryngoscope type not more than twice and limits tracheal intubation by conventional laryngoscopic techniques in general to a maximum of four attempts before using an intubating LMA and tracheal intubation through it; in patients requiring rapid-sequence induction and tracheal intubation, they recommend not to exceed more than three CL attempts.
In a successful prospective study of an airway management (AM) strategy at a teaching hospital, Heidegger and co-workers (31) restricted CL to two attempts followed by flexible bronchoscopy-assisted (FBA) tracheal intubation by an experienced operator, an exemplary strategy to adopt. Combes and co-workers (18) in France in their prospective study of a standardized AM strategy with variable success after multiple interventions allowed four conventional tracheal intubation attempts, including two attempts with the use of a tracheal tube (TT) introducer for tactile blind tracheal intubation, followed by blind tracheal intubation attempts using an intubating LMA. This is a strategy which we cannot accept; conventional tracheal intubations exceeding two attempts should be regarded as failed intubation.
The choice of alternatives to conventional tracheal intubation is less important than the fact that they are practiced alternatives and chosen early when CL has proven to be difficult or has actually failed. Burkle and co-workers (13) reviewed AM choices after failed tracheal intubation by CL in a large teaching hospital; FBA tracheal intubation was the preferred alternative approach with a success rate of more than 90 percent. Connelly and co-workers (19) performed a similar review at their institution; both FBA and Bullard laryngoscope (BL) tracheal intubation were their preferred AM techniques with a success in 90 percent. The manufacturer and the distributors of the BL have not promoted this valuable device which also was considered as strong choice by the Canadian expert working group (22).
Although flexible bronchoscopes (FBs) are essential in difficult airway (DA) management, they require time-consuming preparations, an expert operator with the necessay psychomotor skills, and an experienced assistance. FBA orotracheal intubation is feasible in a variety of DAs but may fail on some occasions; in these situations, usually in patients with a largely restricted pharyngeal space, FBA nasotracheal intubation may be successful. In addition, the TT may occasionally not enter the trachea when the FB is positioned inside the trachea (3); advancement of the TT over the FB into the trachea is a blind procedure and the FB functions like a TT introducer.
The recently released Airtraq optical laryngoscope (AOL) and the various models and systems of the GlideScope video laryngoscope (GVL) were considered by us as valuable supplements to the FB in patients with difficult CL. When properly inserted, both laryngoscopes usually provide an unobstructed view of laryngeal structures (46, 48). The AOL and the GVL are easy to use and the obscured view by soft tissues frequently seen during FBA tracheal intubation is controlled by the operator due to the blade designs; as special feature, the optical and the video camera systems are resistant to fogging. The preliminary favorable results obtained with these devices should be taken into consideration when planning equipment availability and updating formulated strategies for DA management.
LMAs may serve as dedicated airways for maintaining airway patency, ventilation, and facilitating tracheal intubation (15). Intubating LMAs are highly recommended by the British expert working group (32) as backup devices for failed conventional tracheal intubation; there is consensus of opinion that blind TT insertion should be replaced by guidance of the TT by a FB.
The Aintree intubation catheter was specifically designed for FBA tracheal intubation through supraglottic airways (29); its flexibility allows loading over a pediatric FB and its stiffness facilitates railroading of the TT into the trachea. This two-stage technique usually provides an easy passage of the FB and the catheter through the LMA into the trachea without necessitating an expert operator (20, 33). When the FB and the LMA are removed with the catheter in place, a properly selected TT may be easily passed over it into the trachea.
Recommendations of the Austrian Working Group for Airway Management
We highly recommend limiting conventional tracheal intubation to two attempts. Optimum preparation for CL and tracheal intubation with proper patient positioning and external laryngeal manipulation should be already provided for the first attempt; poor laryngeal views at this early state of AM, indicating a difficult conventional tracheal intubation, should give rise to initiate rational decisions: selecting an alternative technique including FBA tracheal intubation and tracheal intubation using an AOL or a GVL, proceeding with a LMA with the option of tracheal intubution using this device as conduit, preferably under guidance by a FB, or awakening of the patient when feasible.
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