Airway Management (Adults) 2024 PDF

Airway management (adults) By Dr. Ali Husam Hadi FABHS-EM  A case I have been asked to see a patient presented from a blast due to kerosine truck explosion with a broken leg, the patient was sedated and had an open tibial fracture....

Airway management (adults) By Dr. Ali Husam Hadi FABHS-EM  A case I have been asked to see a patient presented from a blast due to kerosine truck explosion with a broken leg, the patient was sedated and had an open tibial fracture. The ED sta told me that he presented conscious and only complains from his fracture, so they sedated him to wash the wound and stabilize the fracture. They told me also that he was vitally stable, with no signs of burn apart from the charcoal smell. When I examined the patient I found something else… ff Airways Anatomy  Background Airway management is the cornerstone of resuscitation and is a de ning skill for the specialty of emergency medicine. The emergency clinician has primary airway management responsibility, and all airway techniques lie within the domain of emergency medicine. fi What are the indications for endotracheal intubation? Three essential criteria to intubate... First: Failure to Maintain or Protect the Airway If a patient is unable to maintain a patent airway, the airway should be established by using airway maneuvers such as repositioning, chin lift, jaw thrust, or insertion of an oral or nasal airway. Likewise, the patient must be able to protect against the aspiration of gastric contents, which carries signi cant morbidity and mortality. The presence of a gag re ex is an unreliable indicator of the patient’s ability to protect airway, because the gag re ex is absent in 12% to 25% of normal adults. The patient’s ability to swallow or handle secretions is a more reliable indicator of airway protection. The recommended approach is to evaluate the patient’s level of consciousness; ability to speak when asked his/her name, which provides information about the integrity of the upper airway and level of consciousness; and ability to manage his or her own secretions (e.g., pooling of secretions in the oropharynx, absence of swallowing spontaneously or on command). In general, a patient who requires a maneuver to establish a patent airway or who easily tolerates an oral airway requires intubation for airway protection, unless there is a temporary or readily reversible condition, such as an opioid overdose. fl fi fl  2nd criterion Failure of Ventilation or Oxygenation Ventilatory failure that is not easily reversible or persistent hypoxemia despite maximal oxygen supplementation is a primary indication for intubation. This assessment is clinical and includes an evaluation of the patient’s general status, oxygen saturation by pulse oximetry, and ventilatory pattern. In addition, ABGs may be misleading, causing a false sense of security and delay in intubating a deteriorating patient. The need for prolonged mechanical ventilation generally mandates intubation. An external mask device, (CPAP) and (BLPAP), have all been used successfully to manage patients with exacerbations of (COPD) and congestive heart failure, obviating the need for intubation, but, despite these advances, many patients who need assisted ventilation will require intubation.  3rd criterion Anticipated Clinical Course Certain conditions indicate the need for intubation, even without an immediate threat to airway patency or adequacy of ventilation and oxygenation. Although the patient initially may be protecting the airway and exchanging gas adequately, intubation is advisable to guard against the strong likelihood of clinical deterioration, which can occur after the initial phase of care when the patient is no longer closely observed. Intubation may be indicated relatively early in the course of certain overdoses. Patients with septic shock have high metabolic demand, myocardial depression, increased peripheral oxygen extraction, and vascular permeability. So intubation is needed as pulmonary vascular congestion, hypoxia, and the work of breathing worsen.  A patient who has sustained signi cant multiple traumatic injuries may require intubation, even if the patient is ventilating normally through a patent airway and has adequate oxygen levels. Active resuscitation, pain control, need for invasive procedures and imaging outside of the emergency department (ED), and inevitable operative management dictate the need for early airway control. The thing that connects these indications for intubation is the anticipated clinical course. In each case, it can be anticipated that future events may compromise the patient’s ability to maintain and protect the airway or ability to oxygenate and ventilate. Waiting until these occur may result in a di cult airway. ffi fi  Before intubation Patients will not die if they are not intubated; they will die if their lungs are not ventilated and their blood is not oxygenated. If there are secretions or blood in the oropharynx and the patient is unable to protect his/ her airways then two things should be done: Airway maneuvers: head tilt-chin lift or jaw thrust Suctioning Ventilating the patient does not necessarily mean intubation, Correct bag-valve-mask (BVM) ventilation/oxygenation technique is an underrated skill that will buy you time in the patient with a di cult airway. ffi  Before intubation Proper steps for optimal two-person BVM ventilation include the following: Positioning—ear-to-sternal notch alignment (when clinical scenario permits). Neck slightly exed and head slightly extended. fl  Jaw thrust—displace mandible anteriorly with pressure from long, ring, and small ngers on mandible, not soft tissues. Mask compression—thumb and index ngers should apply rm pressure to face and nasal bridge. fi fi fi  Oral/nasal airways—may help maintain airway patency during BVM ventilation.  Methods of intubation Rapid sequence intubation (RSI): 7 steps including preoxygenation before deep sedation then muscle relaxant. Delayed sequence intubation (deep sedation before preoxygenation then muscle relaxant). Blind nasotracheal intubation X (discontinued) Awake intubation (light sedation then local anasthesia). Oral intubation without pharmacologic agents (crash intubation).  Identi cation of dif cult airway Assessment for potential di culty with laryngoscopy and intubation, BMV, placement of and ventilation with an extraglottic device (EGD), and cricothyrotomy can help formulate a plan for intubation. A patient who exhibits di cult airway characteristics is highly predictive of a challenging intubation, although the emergency clinician should always be ready for a di cult airway even if no sign for di culty on assessment. Some patients may have a single minor anatomic or pathophysiologic reason for airway di culty, whereas others may have numerous di cult airway characteristics, complicating laryngoscopy, bag ventilation, use of an EGD, and cricothyrotomy. Although both sets of patients represent potential intubation challenges, those with multiple di culties may result in a “can’t intubate, can’t oxygenate” (CI:CO) failed airway scenario. ffi ffi ffi fi ffi ffi ffi fi ffi  Managing the airway: decision making The rst determination is whether the patient is in cardiopulmonary arrest or a state of near arrest and is likely not to resist attempts at laryngoscopy. Such a patient is deemed a “crash” airway patient and is treated using the crash airway algorithm by an immediate intubation attempt without use of drugs. If a crash airway is not present, the LEMON, ROMAN, RODS, and SMART evaluations are made to determine if a di cult airway is present, and, if so, awake intubation is advised. For patients who require emergency intubation but who have neither a crash airway nor a di cult airway, RSI is indicated. RSI provides the safest and quickest method of achieving intubation in such patients. After administration of RSI drugs, intubation attempts are repeated until the patient is intubated or a failed intubation is identi ed. fi ffi fi ffi  If more than one intubation attempt is required, oxygen saturation is monitored continuously and, if saturations decrease to 92% or less, the laryngoscopic attempt is aborted (unless the operator feels he or she is on the cusp of successful tube placement) and BMV is performed until saturation is su ciently recovered for another attempt. If the oxygen saturation continues to fall, despite optimal use of BMV or EGD, a failed airway exists. This is referred to as a CI:CO type of failed airway. A second form of failed airway is present when there have been three unsuccessful “best attempts” at laryngoscopy, because subsequent attempts by the same clinician are unlikely to succeed. The three failed laryngoscopy attempts are de ned as attempts by an experienced clinician using the best possible patient positioning, device, and technique. Three attempts by a trainee using a direct laryngoscope may not count as best attempts if an experienced emergency clinician is available or video laryngoscopy has not yet been attempted. In addition, the emergency clinician can identify a failed airway after even a single laryngoscopic attempt if it is judged that intubation likely will be impossible (e.g., grade 4 laryngoscopic view with DL, despite optimal patient positioning and use of external laryngeal manipulation) and no alternative device (e.g., videolaryngoscope, intubating LMA) is available. fi ffi  Dif cult airway When preintubation evaluation identi es a potentially di cult airway the approach is based on the premise that muscle relaxants generally should not be used and awake method should be used instead unless the emergency clinician believes that: 1. Intubation is likely to be successful 2. Oxygenation can be maintained via BMV or EGD if the patient desaturate during an intubation attempt 3. The patient will not experience cardiovascular complications or arrest from precipitous desaturation or hemodynamic collapse following administration of RSI medications. Even if di cult features or chronic diseases exist & RSI is thought to be the best approach, then all other elements should be optimized to increase rst attempt success. This includes use of videolaryngoscope, robust preoxygenation and cardiovascular optimization with uids, blood, and pressor agents, as necessary. Double setup preparation in which another physician is ready to do cricothyrotomy if intubation fails. ffi fi fi fi ffi fl  Direct laryngoscopy The optimal position to maximize laryngoscopic visualization of the larynx is: The head is extended. The neck is exed. The base of the ear is aligned with the sternal notch. The facial plane is horizontal, parallel to the ceiling. The facial plane should be positioned between the laryngoscopist’s xyphoid process and umbilicus (see Figs. 22.19A and 22.19B). Large individuals or those with morbid obesity often require putting a blankets, sheets, or towels to raise the head and shoulders to achieve ear-to-sternal notch alignment. fl  Rapid sequence intubation RSI is the cornerstone of modern emergency airway management and is de ned as the nearly simultaneous administration of a potent sedative (induction) agent and neuromuscular blocking agent, after a period of preoxygenation and cardiopulmonary optimization, for tracheal intubation. This approach provides optimal intubating conditions and was initially developed to safely and e ectively intubate patients while minimizing the risk of aspiration of gastric contents. The central concept of RSI is to take the patient from the starting point (eg, conscious, breathing spontaneously) to a state of unconsciousness with complete neuromuscular paralysis, and then to achieve intubation without interposed assisted ventilation. There is risk of aspiration of gastric contents, so the purpose of RSI is to avoid positive- pressure ventilation until the ETT is placed correctly in the trachea, with the cu in ated. ff fi ff fl  1. Preparation In the initial phase, the patient is assessed for intubation di culty and abnormal physiology, unless this has already been done, and the intubation is planned, including: Determining dosages and sequence of drugs, Tube size, Laryngoscope type, blade, and size. Drugs are drawn up and labeled. All necessary equipments are assembled. All patients require continuous cardiac and pulse oximetry monitoring. At least one and preferably two good quality intravenous lines should be established. A rescue plan for intubation failure should be developed and made known to the members of the resuscitation team. ffi  2. Preoxygenation The goal of preoxygenation is denitrogenation of the alveoli and formation of an oxygen-rich reservoir within the lung’s FRC. The traditional method for preoxygenation involved having the patient breathe, for 3 minutes at normal tidal volumes, 100% oxygen at 15 L/min ow through a nonrebreather mask. When preoxygenation is performed e ectively, the patient may have as much as 6 to 8 minutes of safe apnea before oxygen desaturation to less than 90% occurs. The time to desaturation to less than 90% in children, obese adults, late-term pregnant women, and patients who are acutely ill or injured is considerably shorter. ff fl  Desaturation time also is reduced if the patient does not inspire 100% oxygen or has signi cant intrapulmonary shunting or dead space. Patients with in ltrative lung disease, pulmonary edema, or ARDS may never achieve adequate preoxygenation despite maximal ambient pressure supplemental oxygen. If saturations remain at 93% or less despite these e orts, then the patient should be transitioned to BiPAP to increase ETO2. If time is insu cient for a full 3-minute preoxygenation phase, eight vital capacity breaths (the largest breaths the patient can take with greatest e ort) with high- ow oxygen can achieve oxygen saturations and apnea times that match or exceed those obtained with traditional preoxygenation. fi ffi fi ff ff fl  3. Pre-intubation optimization Airway management can be made more complex by unstable hemodynamics and impaired patient physiology. Shock states, severe myocardial depression, or preoxygenation failure don’t necessarily make tracheal intubation harder, but they can increase patient morbidity by shortening the safe intubation time or risking hypoxic injury or circulatory collapse. Patient outcomes can be compromised in those with hypotension or shock caused by bleeding, dehydration, sepsis, and primary cardiac pathology, even if tube placement is smooth, fast, and successful. Induction agents can potentiate peripheral vascular dilation and exacerbate hypotension. Patients who present with low intravascular volume, right heart disease, or poor vascular tone can su er circulatory collapse after RSI drugs are administered, particularly after positive pressure ventilation is initiated. When time allows, abnormal hemodynamic parameters should be improved as much as possible before intubation. A balanced uid or blood product replacement is recommended, along with pressors (norepinephrine), optimal oxygenation, and control of any aggravating factors, such as external hemorrhage. fl ff 4. Paralysis with induction 5. Positioning In this phase, a potent sedative agent The patient should be positioned is administered by rapid intravenous like discussed earlier for intubation (IV) push in a dose capable of as consciousness is lost. producing unconsciousness rapidly. After administration of an induction This is immediately followed by rapid agent and NMBA, although the administration of an intubating dose of patient becomes unconscious and an NMBA, either succinylcholine at a apneic, BMV should not be initiated dose of 1.5 mg/kg IV or rocuronium 1.2 unless the oxygen saturation falls to mg/kg. 92%.  6. Placement of tube Approximately 45 to 60 seconds after administration of the NMBA, the patient is relaxed su ciently to permit laryngoscopy. This is assessed most easily by moving the mandible to test for mobility and absence of muscle tone. Place the ETT during glottic visualization with the laryngoscope. Con rm placement. If the rst attempt is unsuccessful but oxygen saturation remains high, it is not necessary to ventilate the patient with a bag and mask between intubation attempts. If the oxygen saturation is approaching 92%, the patient may be ventilated brie y with a bag and mask between attempts to reestablish the oxygen reservoir. fi fi fl ffi  7. Post-intubation management After con rmation of tube placement by ETCO2, obtain a chest radiograph to con rm that mainstem intubation has not occurred and to assess the lungs. If available, place the patient on continuous capnography. In general, the focus is on optimal management using opioid analgesics and sedative agents to facilitate mechanical ventilation. An adequate dose of a benzodiazepine (eg, midazolam) and opioid analgesic (eg, fentanyl or morphine) is given to improve patient comfort and decrease sympathetic response to the ETT. Propofol infusion with supplemental analgesia is an e ective method for managing intubated patients who do not have hypotension or ongoing bleeding and is especially helpful for management of neurologic emergencies because its clinical duration of action is very short (0.8). In patients with profound shock, all induction agents have the potential to exacerbate hypotension. Shock-sensitive RSI hinges on three primary optimization principles—volume resuscitation with isotonic uid or blood prior to induction (if time permits), reduced dose of a hemodynamically stable induction agent, and titration of peri-intubation pressor agents. fl  Potential Cervical Spine Injury Historically, most patients with suspected blunt cervical spine injury were intubated orally by direct laryngoscopy with in-line cervical spine immobilization, whether done as an awake procedure or with neuromuscular blockade. However, with this approach, glottic views can be inadequate, and excessive lifting force often is required. Patients with known cervical spine fractures are optimally managed with a exible bronchoscope to minimize cervical spine motion; however, in the emergency setting, a videolaryngoscope should be used and, if not available, a direct laryngoscope also can be used. A videolaryngoscope, intubating LMA and multiple other devices like the bougie have been used without excessive lifting force or cervical spine movement and has excellent intubation rates. fl Fiberoptic and Video Intubating Stylets Extraglottic and retroglottic devices Laryngeal mask airway (LMA) Combitube Thank you