Airway management outside the operating theatre:
Col (Dr) Mathews Jacob, MD, DNB, MNAMS
Associate Professor, Department of Anesthesiology and critical Care
AFMC, Pune

            Airway management remains one of the essential life saving skills. Airway management is inevitably required for anypatient who is unable to maintain oxygenation,ventilation and is atrisk toprotect his airway from aspiration. Rapid assessment to identify patients at risk from failed intubation and oxygenation is essential to avoid a potentially disastrous emergency “Can’t Intubate, Can’t Ventilate” scenario.1 This review is intended to assist anesthesiologists in airway management in a situation, where we can’t expect a perfect environment like operating room (OR).
Introduction:
Airway management is one of the herculean tasks where anesthesiologist will be needed to manage the scenario. Anesthesiologists are regularly called upon to placesanywhere, to protect and maintain airway, which usually include CT scan centre, MRI centre, and psychiatry ward for ECT, Interventional radiology centre (IRC) where elective procedures are done under anaesthesia. Airway management outside OR need not be elective only, any patient with poor GCS<7 in wards, emergency rooms, ICUs, cardiac arrest situations, maxillofacial trauma2 require immediate securing of airway. In any of the places, manpower, equipment, difficult airway, and risk of aspiration are a definite hurdle for management. However, there is no defined guidelines or protocol to manage airway outside OR.  When the situation to handle airway is outside operating room, we hardly get time to prepare and have a controlled environment to manage appropriately.Assessment and decisions have to be made rapidly. The required things for securing airway including drugs and equipmentsneed to be taken to the venue. The airway management outside the OT includes both intubation and extubation, which falls in the realm of the anaesthesiologist.
Definitions:
Elective airway management: airway management in a controlled manner with proper airway assessment and adequate preparation in a safe environment and safe patient in terms of cardiorespiratory status. (e.g. Intubation under general anaesthesia )
Urgent Airway Management:management of the airway in a patient whose cardiorespiratory status is deteriorating and in need of eventual intervention (e.g., respiratory distress requiring intubation).
Emergent Airway Management:  management of the airway in a patient who needs immediate support and intervention (e.g., cardiac arrest).
Anticipated problems and planning:

• Local circumstances:

Data suggests that management of airway outside OR leads to higher incidences of difficult intubation.3 This may be highly due to emergent presentation of patient at any time leading to insufficient planning and preparation for this group. When the emergencies are unpredictable, it is always better be prepared over long period of time. Furthermore, the seniority and experience of available staff must be sufficient to meet the patient’s needs. Whenever possible, the patient can also be moved to OR for securing airway, as the equipment available will not be as standard as in OR. But condition of the patient and local circumstances play a major role in shifting. In some cases of difficult airway, where general anaesthesia will be required for short procedures outside OT (e.g., CT scan, IRC Centre), it will be better to secure the airway inside OT with the assistance of senior anesthesiologists and then shift the patient.

• Emergency airway box:

            In any OR, there will be a difficult airway cart. Similarly, there should be an emergency airway box which must contain airway devices of various sizes including, guedels airway devices, nasopharyngeal airway devices, gum-elastic bougies, masks, self-inflating resuscitation bag capable of delivering 100% oxygen, Bains circuit, supraglottic devices, endotracheal tubes, retrograde intubation sets, emergency tracheostomy set, jet ventilator set, laryngoscope with blades. The box must also contain drugs necessary for intubation and extubation. Whenever the anesthesiologist is called for management of airway outside the OR, this emergency airway box must always be ready to be carried to.

• Rapid assessment of airway:

            In elective situations, we will get ample time to assess and prepare for airway management. Airway assessment always includes history of previous difficult airway. In an urgent situation, it is always better if you can spend 2 minutes atleast to do rapid airway assessment, which will help in planning the management of airway. Even in an emergent scenario, where you won’t get even that 2 minutes time, you should always have an alternate plan if you meet with difficulty.
We suggest the assessment of difficulties at various stages of airway management; this assessment should not take more than 2 minutes for an experienced anaesthesiologist. It is otherwise head to chest scanning.

• Assessment of difficult Face mask (FM) ventilation – BONES & MOANS
• B-Beard                             i.    M-Mask seal
• O-Obstruction/obesity        ii.   O- Obstruction/obesity
• N-No teeth                                    iii.  A-Age>55
• E-Elderly                            iv.   N-Neck mobility
• S-Snoring                           v.    S-Stiff lungs
• Assessment of difficult OPA /NPA insertion
• OPA- conscious/semiconscious patients with intact gag reflex
•  NPA- basal skull fracture
• Assessment of difficult SGA insertion – RODS
• R- Restricted mouth opening
• O- Obstruction/obesity
• D- Disrupted anatomy
• S-Stiff lungs
• Assessment of difficult laryngoscopy- examination of
• Teeth- buck teeth, missing tooth, length of incisors, upper lip bite test
• Mouth- inter-incisor distance, Mallampati score, High arched palate
• Mandibular space- Thyromental distance, Mandibular compliance
• Neck-Sternomental distance, cervical spine mobility, circumference
• Assessment of difficult ETT insertion – LEMON
• L-Look externally
• E-Evaluate 3-3-2 =>Inter-incisor gap > 3 fingers, Thyromental distance > 3 fingers, Thyroid to floor of mouth >2 fingers
• M-Mallampati
• O-Obesity/obstruction
• N-Neck mobility
• Assessment of difficult surgical airway – BANG
• B-Bleeding
• A-Agitation
• N-Neck scarring
• G-Growth neck (vascular)
• Assessment of risk of aspiration
• Nil per oral status
• Diabetes
• Pregnancy
• Gastro esophageal reflux disease
• Hiatus hernia

• Man power and line of management

            Plan of management always depends on anticipated difficult airway, equipment issues and manpower available. Operating room assistant is the ideal person to assist us in difficult airway scenario. But he will not be available in places outside OR. So the plan and preparation for difficulty should be followed as per standard of procedure of that particular institution or as per ASA task force difficult airway algorithm.4 For e.g., plan for difficult intubation, plan A – RSI à Plan- B - BMV àPlan- C – Proseal LMA àPlan - D -Surgical airway. Adequate access to the head should always be obtained. Right preparation, strong teamwork and communication between all the specialties involved in the delivery of emergency airway management prevents any catastrophes.
Line of management always depends upon two important factors, first is whether it’s an elective, urgent or emergent scenario. Second is normal or anticipated difficult airway.

• Pre-oxygenation- 4 vital capacity breaths or spontaneous breathing for 3 minutes
• Sedation and paralysis in anticipated normal airway. Choice of drugs depending on clinical status of the patient.
• RSI and cricoid pressure in patients with risk factors for aspiration
• Awake fiber optic intubation as a first choicein difficult airway.
• In case of failed intubation- stop struggling with laryngoscopy and start oxygenation by facemask before significant desaturation (below 96%),5 try visualization of the larynx by changing the size and type (Macintosh to Miller) of laryngoscope blade and externally manipulating the larynx using the BURP (backward, upward, rightward pressure) maneuver, use adjuvants like bougie and stylet for endotracheal tube insertion. Call for help, try to ventilate using face mask or supraglottic airway (SGA) and follow ASA algorithm for difficult airway
• Confirmation of endotracheal tube position by direct visualization, auscultation, capnography.

• Monitoring:

Though we manage all equipments, drugs and manpower, monitors are always compromised in places outside OR. EtCO2 monitoring is recommended for confirmation of endotracheal tube in place.
There are case reports suggesting oesophageal intubation6resulting in death of patient without adequate monitors. Data also show that interpretation of monitoring is equally important, as there are case reports showing death of patient because of the inadequate knowledge about EtCO2 by junior resident.
Recommendations:

• Depicted plans should be available for management of airway outside operating rooms.
• Things required to act faster should always be ready and accessible – it is mandatory to check emergency airway box regularly.
• Prompt availability of helping hands- nursing officer or operating room personnel to assist the airway management outside OT.
• Consultation and suggestion of senior anaesthesiologist always prove fruitful.
• Planning in advance that who will respond the emergency during the time frame, and clear flow chart pattern of protocol to handle any emergencies will greatly attenuate the morbidity and mortality due to failed airway to a great extent.
• Call for help whenever you are in difficult airway scenario, because its patient’s life which is important.
• Regardless of the circumstances leading to the airway failure, a deliberate approach must be used to ensure that oxygenation is preserved, and that the airway is ultimately secured
• Decision to move the patient before securing airway must consider local factors and the condition of the patient. If airway is getting compromised, secure the airway before moving him to other place.
• Capnography is always recommended for any intubation.
• Training of residents, staffs, OR assistants and ward personnel on airway management should be done regularly in the form of simulation and team training.

References:

• Heard AM, Green RJ, Eakins P. The formulation and introduction of a 'can't intubate, can't ventilate' algorithm into clinical practice.Anaesthesia. 2009 Jun;64(6):601-8.
• Rashid M Khan, Pradeep K Sharma,1 and Naresh Kaul. Airway management in trauma Indian J Anaesth. 2011 Sep-Oct; 55(5): 463–469.
• M. S. T. LIM, J. J. HUNT-SMITH. Difficult Airway Management in the Intensive Care Unit: Practical Guidelines. Critical Care and Resuscitation 2003; 5: 43-52.
• Apfelbaum, Jeffrey L. M.D.; (Chair); Hagberg, Carin A. M.D.; Caplan, Robert A. M.D.; (Chair); Blitt, Case. Practice Guidelines for Management of the Difficult Airway: An Updated Report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway.Anesthesiology: February 2013 - Volume 118 - Issue 2 - p 251–27
• Leviton R, Ochroch EA. Airway management and direct lary ngoscopy .  A review  and update. Crit Care Clin 2000;16: 373-8.
• Kenneth C. Dittrich, MD. Delayed recognition of esophageal intubation-Case Reports. CJEM 2002;4(1):41-44