An obese 39-year-old female is scheduled for a laparoscopic cholecystectomy under general anesthesia. She takes no meds and has no allergies. She is 5′4″ (161 cm), 220 lb (100 kg), with a BMI 38.6 kg·m−2. She denies reflux. On physical exam, she has a Mallampati Class II airway, has 4 cm mouth opening, and a good neck extension. Her hyomental distance is also less than 5 cm and her hypothyroid distance is about 3 cm. She has no past surgical history except for a cesarean section under epidural. Upon arrival at the operating room, standard monitors are placed on the patient. Following denitrogenation and induction of anesthesia with 200 mg of propofol, rocuronium (40 mg) is administered for muscle relaxation. Direct laryngoscopy is attempted with #3 Macintosh blade. Only a large epiglottis is seen with no improvement in the view following the application of laryngeal pressure. A #3 Miller blade is then used to lift the epiglottis, but vocal cords are still not visible. An Eschmann Tracheal Introducer (“bougie”) repeatedly goes into the esophagus. Bag-mask-ventilation (BMV) remains adequate. Help and the difficult airway cart are summoned. A #3 Intubating Laryngeal Mask Airway (LMA-Fastrach) is placed, resulting in adequate ventilation. An attempt at blind intubation through the Intubating Laryngeal Mask Airway (ILMA) is unsuccessful. In a further attempt, a 7.0-mm ID endotracheal tube (ETT) is loaded onto the FAST (Foley fiberoptic airway stylet, Clarus Medical LLC, Minneapolis, MN) and placed through the ILMA. The ILMA is manipulated till vocal cords are visualized and the ETT is placed into trachea without difficulty. Correct ETT placement is confirmed by means of end-tidal CO2 and auscultation. The surgical procedure proceeds uneventfully. At the conclusion of the cholecystectomy, tracheal extubation is achieved with no difficulties when the patient is awake and alert. Appropriate monitoring and disposition of the patient are provided.
WHY SHOULD WE DOCUMENT BOTH THE OCCURRENCE AND THE MANAGEMENT OF A DIFFICULT OR FAILED AIRWAY?
As indicated in earlier chapters (most notably Chapter 1), a difficult or failed airway is not the same as a difficult or failed intubation, or a failed attempt at using an extraglottic device (EGD) or BMV. It is critically important to be able to accurately describe, document, and communicate an adverse event related to airway management difficulty and/or failure.
Failure to manage successfully an airway problem may certainly threaten patient safety and may also threaten the welfare of any airway practitioner. Attempts to improve outcomes in the management of a difficult/failed airway would require a system which records and reports this information to a widely disparate group of practitioners. The challenge is to create a system that conveys this information to this disparate group of practitioners dispersed in location and time. Practitioners are both legally and professionally vulnerable if they either fail to record or communicate critical information or fail to access and be aware of it. This underscores the importance of clear documentation of untoward airway events.
Many difficult airways can be predicted after a routine careful airway examination. Even so, unanticipated difficult and failed airways continue to occur.1–3 One to 3% of patients undergoing general anesthesia present with unanticipated difficult airway/intubations when managed with conventional laryngoscopy.4,5
A history of difficult airway has been shown to be an independent risk factor for a patient presenting with second difficult airway.6,7 Documenting and communicating these incidents can therefore be crucial in preventing future airway disasters. Identifying patients who have had a previous “difficult airway” incident through accurate written and verbal documentation ensures that practitioners are not dependent on inaccurate verbal histories to assess these at-risk patients.
The American Society of Anesthesiology Closed Claims Analyses has consistently identified adverse airway outcomes as the largest class of injury.8,9 Of the events occurring in the 1980s, 17% were due to difficult intubation. Cheney,10 in an ASA newsletter published in June 1997, compared the closed claims cases from the 1970s, 1980s, and 1990s. The three most common adverse respiratory events causing death or brain damage were inadequate ventilation, esophageal intubation, and difficult intubation. A marked reduction among these adverse events was noted over time. Interestingly, while inadequate ventilation fell progressively (22% in 1970s, 15% in 1980s, and only 7% in 1990s) and the incidence of death or brain damage decreased, difficult intubation as a cause of death or brain damage increased from 5% in 1970 to 12% in 1990s. The number of claims in 1990s due to difficult intubation was too small to reach statistical significance.
The conclusion is interesting: while the decrease in inadequate ventilation and esophageal intubation may be due to the introduction of pulse oximetry and end-tidal CO2 monitoring, the approach to a difficult intubation will require a strategy with alternative airway techniques (Plans A, B, and C).
More importantly, the 4th National Audit Project (NAP4), as well as other studies, have shown that repeated attempts at intubation causes swelling and bleeding, leading to a “cannot intubate, cannot oxygenate” situation, in addition to other complications.9,11,12
In the Closed Claims review, Caplan et al.8 showed that more than 50% of the difficult airway claims were in airways that were anticipated to be difficult. In the NAP4 study, 133 cases had major airway management complications. Of the 133 cases, half (66) were anticipated difficult airways. Of the 66 anticipated difficult airways, 41 of them had a history of airway management problems. A history of difficult airway management was found in the medical records of 32 of the 66 anticipated difficult airways. Only 14 of these 66 patients had received verbal or written communication in this regard. This serves to remind us that accurate and detailed communication of the patient’s airway management is critically important. It is not just enough to say the patient has a difficult airway.13
The “Difficult Airway Guidelines” of the American Society of Anesthesiologists (1993, updated in 2003, and then in 2013) repeatedly recommend documentation of airway management difficulty on the patient record AND in verbal discussion with the patient.
HAS THERE EVER BEEN A CONCERTED EFFORT TO ESTABLISH A CENTRAL “DIFFICULT AND FAILED AIRWAY REGISTRY”?
Coincident with the development of these guidelines, an Anesthesia Advisory Council representing anesthesiologists, otolaryngologists, and experts in risk management joined together with the nonprofit MedicAlert Foundation to establish a National Difficult Airway/Intubation Registry. The major objective of this registry was to develop mechanisms for a uniform documentation and dissemination of critical information related to airway management difficulty and failure to protect patients. As a result, in 1991, the Anesthesia Advisory Council along with the MedicAlert Foundation established the category “Difficult Airway/Intubation.” In 1992, The World Federation of Societies of Anesthesia officially endorsed this initiative and in the same year, the American Academy of Otolaryngology-Head and Neck surgeons followed suit.
The Society for Airway Management (SAM) has endorsed the National MedicAlert. In 2014, the SAM’s MedicAlert Task Force updated a designated Difficult Airway Registry (www.medicalert.org/everybody/difficult-airwayintubation-registry). Currently, the SAM is developing guidelines for dissemination of critical information on the difficult airway. Any health care provider who manages airways is able to uniformly document the patient’s airway physical examination, the management of the difficult airway, and the patient’s outcome, all via the internet. A registration form can be downloaded, completed, and given to the patient. Once the patient is registered, this information can be accessible worldwide.
IS THERE ANY EVIDENCE THAT VERBAL ADVICE, MEDICAL RECORD DOCUMENTATION, OR REGISTRIES HAVE ANY EFFECT IN REDUCING THE INCIDENCE OF SUBSEQUENT ADVERSE AIRWAY MANAGEMENT EVENTS?
Two small studies have shown a lower incidence of adverse outcomes associated with a prior knowledge of difficult airway. The first employed The MedicAlert Foundation Registry Database. By February of 1994, a total of 111 patients had been enrolled in the registry from over 30 states within the United States. Preliminary results suggested that knowledge of a prior difficult airway led to the use of fewer airway management techniques, and a lower incidence of adverse outcomes.14
In the second study, a computerized In-Hospital Difficult Airway Registry had been developed at the Beth Israel Deaconess Medical Center in Boston, MA.15 One hundred and twenty-nine patients were entered into the registry during the period of April 1995 and April 1997. Of these patients, 31 returned at least once to the operating room. Uniform documentation of the prior airway management difficulty was available on the permanent medical record, reducing the need to rely on the patient’s memory. There were no adverse outcomes related to airway management in their repeated visit to the operating room. Some locally based hospital systems have been able to track and warn future anesthesia practitioners by using their Anesthesia Information Management Systems (AIMS).16,17
The operating room is not the only location in which a difficult airway may be encountered in a patient. Both the Peterson report9 and NAP411 identified a variety of locations outside the operating theater/room, ICU, hospital wards, and the emergency department (ED) in their discussions.
John Hopkins University developed a comprehensive difficult airway program which targeted three contributing factors that would increase complications related to airway management11: (1) inability to access the written medical record; (2) lack of immediate access to equipment and supplies necessary to manage a difficult airway; and (3) lack of availability of trained personnel to help manage and secure the airway. The program incorporated electronically communicated patient information which could be accessed any time. It also mandated a green “difficult airway bracelet,” immediate access to specific equipment and the immediate availability of anesthesia and surgical staff. Following the implementation of this program, they showed that the number of emergency surgical airways were reduced from 1992–1995 6.5 ± 0.5 per year to 1996–2006 2.2 ± 0.89 per year.18
Practice guidelines have been promulgated by anesthesia societies in North America and Europe, all recommending verbal communication with the patient and practitioners and written documentation of adverse airway management events.1,19–21,22–24 Entering patients into a difficult airway registry is also advisable.
WHO SHOULD UNDERTAKE THE VERBAL ADVICE AND WRITTEN DOCUMENTATION? WHEN SHOULD THAT OCCUR?
If feasible, patients should be verbally advised in jargon-free language about the event by the practitioners themselves when the patient is alert and oriented in the post-anesthesia care unit, recognizing that this may not always be possible. More importantly, patients should be able to confirm their understanding of the gravity of the situation and its details are understood. Because of the residual effects of medications, the complexity of the event and the vagaries of memory, a written narrative must also be given to the patients to take with them so they can show to subsequent practitioners if possible.
WHO SHOULD BE ADVISED OF THE EVENT? WHERE SHOULD WE DOCUMENT THE INFORMATION?
Besides the patient, the following should be briefed either verbally or in written form:
Patient family members if available
Primary care provider notified in writing
Depending on the context, the surgeon, the intensivist, or the admitting physician, should be told at time after the intubation.