Author’s note: This hypothetical case is abstracted from current literature on pitfalls in airway management and is not an actual patient care case.
A 52-year-old male suffers a sudden cardiac arrest in a public venue. Bystanders initiate CPR. A BLS crew from the first-arriving ambulance continues CPR and applies an automated external defibrillator (AED) and defibrillates the patient once prior to arrival of an ALS ambulance. CPR is continued, and the patient is determined to be in ventricular fibrillation (v fib) after reviewing the rhythm on the ALS unit’s monitor.
The patient is defibrillated again but remains in refractory v fib. One ALS provider attempts to obtain IV access while a second attempts an endotracheal intubation (ETI). The intubator requests CPR be interrupted during the intubation attempt, encounters a difficult airway and obtains only a Grade III (Cormic-Lehane scale) view of the airway.
After a 40-second pause in CPR, the intubation attempt is unsuccessful, and CPR is resumed. On the third attempt, the patient is successfully intubated. A total of one minute and 50 seconds of CPR interruption results from the multiple ETI attempts. In addition, the multiple intubation attempts have distracted the other ALS provider from ACLS interventions, such as drug administrations and defibrillation.
The patient has a return of spontaneous circulation (ROSC) after 14 minutes of ACLS interventions but suffers a second arrest in transit to the hospital from which he can’t be resuscitated. Data recording during the resuscitation shows that the CPR percentage (total amount of time that chest compressions were actually being performed) for the first five minutes of ACLS was 52%.
Advanced airway management, specifically ETI, has been the standard of care for paramedics and a defining procedure of prehospital emergency care for more than 25 years.1 During the past 10 years, prehospital ETI literature has demonstrated trends of increased morbidity and mortality for patients being intubated for cardiac arrest, traumatic brain injury (TBI) or multisystem trauma.2–4
Two common themes are associated with poor outcomes from prehospital advanced airway management: process issues with airway management procedures and physiological issues resulting from not tailoring the airway management approach to the patient’s physiological derangements.
Process issues result from not having adequate trained personnel available during ETI and not formulating adequate planning and preparation to perform ETI. Too often a single prehospital provider will attempt to perform basic and advanced airway management on their own because of personnel limitations. This results in sub-optional ventilation of the patient and inadequate preparation for advanced airway placement, which can lead to higher failure rates, nonventilatory periods and complication rates.
ETI must be approached as a two-provider procedure at minimum—one provider to prepare for and perform the intubation, and a second to ensure BLS airway control and ventilation, and assist during the intubation attempt.5 Several authors expand on this concept, mandating a minimum of three providers for ETI on a trauma patient, with the third provider holding manual C-spine immobilization during the ETI attempt.6–7
The airway assistant doesn’t necessarily need to be an ALS provider, but could be an EMT with minimal additional training in assisting with ETI and other advanced airway procedures. In the absence of a trained airway assistant, the prehospital provider should reevaluate using ETI to secure the airway and consider using an alternate approach, such as placing a supraglottic airway.
In addition to having adequate trained personnel available for ETI, it’s vital to
conduct planning and preparation for advanced airway management. This consists of the following:
>> Assessing for the need of basic and advanced airway intervention;
>> Ensuring adequate BLS control of the airway and ventilation is present;
>> Having an emergency plan if BLS ventilation is inadequate;
>> Assessing for difficult airway features and developing a strategy to deal with them;
>> Having a plan of action for use of an alternate airway in the event of failed ETI; and
>> Having procedures for confirming and securing placement of the ET tube or alternate airway.8
Part of this planning involves having equipment and medications that may be required based on the assessment of the patient, and having the airway strategy selected, assembled, checked and ready. This equipment should include BLS airway adjuncts, suction, laryngoscope, ET tubes, stylets, medications for drug-facilitated intubation, supraglottic or other alternate airway devices, confirmation and securing devices.
Having a process in place is a good start to safe and effective prehospital ETI, but it’s only part of the solution and must be coupled with adjusting the airway management strategy to address the patient’s physiological derangements. An airway management approach that doesn’t take into account that the patient’s physiology can worsen their outcome despite successful ETT placement. This has been demonstrated in cardiac arrest patients and patients with severe TBI.2–4
Pittsburgh EMS has begun adjusting its airway management strategy to match the patient’s physiological status and resources available on scene. The approach involves customizing the airway management approach to the following categories: cardiac arrest, isolated severe TBI or suspected medical intracranial hemorrhage, severe or multisystem trauma and general medical patients. This article focuses on cardiac arrest patients.
Recent literature has demonstrated worse outcomes for patients in cardiac arrest with ETI and better outcomes with an approach that defers ETI until later during the resuscitation.3–4,9 There are probably two reasons for ETI negatively affecting cardiac arrest outcomes: interruptions in CPR for ETI and overventilation after ETI. Physiologically, cardiac arrest with CPR in progress in a low-flow state appears to be sensitive to anything that may further compromise perfusion. One of the major determinates for survival is the percentage of time during the arrest that high-quality CPR is actually being performed.10 (See Table 1)
Controlling all other factors, physically performing quality chest compressions for greater than 60% of the time the patient is in arrest significantly improves the odds of the patient surviving to discharge, with greater than 80% being optimal performance.10 CPR percentages in these ranges maximize coronary perfusion pressure (CPP), which is a major determinant for achieving ROSC.11 Unfortunately, prehospital ETI has been associated with significant interruptions in CPR.
One researcher demonstrated in a review of two EMS systems that the mean chest compression interruption for the first ETI-associated event was 46.5 seconds.12 He also found that there was a median of two ETI-related chest compression interruptions per patient, with a median total chest compression interruption time of 109.5 seconds.12 One-fourth of the patients reviewed had total ETI-related chest compressions interruptions exceeding 180 seconds.12 This loss of chest compression time and reduced CPR percentage would have significantly decreased CPP and probably reduced survival.
The 2010 ACLS Guidelines state, “advanced airway placement should not cause significant interruptions in chest compressions or delay defibrillation.”13 Successful ETI may continue to negatively affect the physiology of cardiac arrest by allowing for easier overventilation of the patient. This increases minute volume by increasing ventilatory rate and tidal volume. Overventilation will decrease CPP during the arrest phase.14 Overventilation increases intrathoracic pressure, which decreases passive venous return to the right side of the heart. This decreases preload, which decreases cardiac output during CPR and, therefore, CPP.14
Given the evidence, advanced airway management in cardiac arrest must be performed so it doesn’t further negatively affect the low-flow perfusion state that exists. Pittsburgh EMS generally defers advanced airway management for the first five minutes of the resuscitation and maximize perfusion by prioritizing high-quality CPR, vascular access and medications, specifically vasopressors.
As preparation for our upcoming participation in a Resuscitation Outcomes Consortium (ROC) cardiac arrest study, we have slightly modified this guideline to perform advanced airway placement after three cycles (a cycle being five sets of 30 compressions and two ventilations) of CPR, which generally ends five to six minutes into the arrest.
This approach ensures adequate BLS control of the airway is present, high-quality CPR is being performed and ACLS resuscitation is in progress prior to attempting advanced airway placement. If at any time the airway can’t be managed with BLS, the airway management team has the option to “bail out” and immediately secure the airway by the most appropriate strategy. In preparation for ETI, the airway manager proceeds to assess the patient for difficult airway traits. The mnemonic ANOTES is used to assess
A: Awake patients (with a Glasgow Coma Scale score greater than 3);
N: Neck (short or “no neck”);
O: Obese patients;
T: Trauma (facial, airway or requiring C-spine stabilization);
E: Emesis; and
S: Space: limited space about the head to manage the airway.
These airway traits have been associated with increased probability of unsuccessful ETI.8,15 Based on the airway difficulties identified, the airway team anticipates encountering a difficult airway on the ETI attempt and formulates a plan to mitigate the potential difficulties. Approaches in cardiac arrest could include laryngeal manipulation during the attempt (e.g., thyroid pressure, BURP [backward, upward, rightward pressure on the larynx] or external laryngeal manipulation).
Other options include elevating the head of the patient (on the longboard, stretcher or variant of head-elevated laryngoscopy position) or moving the patient to a better location or position prior to the ETI attempt.
The airway manager always has the option, based on assessment of the patient, to defer ETI and instead place a supra-glottic airway device, especially if the airway is predicted to be difficult with a high potential for unsuccessful ETI. Once the airway strategy has been formulated, the final step is to ensure all equipment has been prepared.
With all planning and preparation completed, the airway management team waits until the third two-minute CPR cycle has been completed. At this point, the patient’s perfusion should be maximized with five minutes of high-quality CPR, vascular access and vasopressor administration in addition to defibrillation and anti-arrhythmic administration if indicated. Advanced airway placement can now occur.
If a device was the selected approach, placement can be accomplished with no chest compression interruption, and the confirmation procedure can be performed with only a brief compression interruption, if needed, to auscultate breath sounds.
If the ETI approach is chosen, laryngeal manipulation is encouraged on all ETI attempts applied by the airway assistant if selected, and the ETI attempt is made with compressions in progress.
It’s optimal if ETI can be accomplished with no compression interruption, but one interruption of less than 10 seconds is permitted, if necessary, to identify anatomy and pass the tube. It’s the airway assistant’s responsibility to monitor this time period and instruct the compressor to resume compressions at 10 seconds.
If the ETI attempt was successful, tube placement is confirmed by a minimal chest compression pause (if needed), and the tube is secured. If the ETI attempt is unsuccessful, then no further attempts are permitted. After another two-minute cycle of CPR, an airway device is placed. Once an advanced airway is placed, the compressor performs continuous chest compressions without interruption. Normoventilation at eight to 10 ventilations per minute is performed with minimal tidal volumes to prevent significant increases in intrathoracic pressure. Monitoring tidal volume and ventilatory rate is enhanced using waveform capnography.
Advanced airway management, including ETI, can be performed safely and effectively by taking a process approach matched to the patient’s physiological status. In cardiac arrest, advanced airway management must take no more than two attempts to place a device and result in minimal, if any, CPR interruption to maximize CPR outcome. This approach, coupled with judicious control of ventilatory rate and volume, will maximize coronary perfusion pressure during the arrest phase and will enhance survival. JEMS
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8. Wang HE, Kupas DF, Greenwood MJ, et al. An algorithmic approach to prehospital airway management. Prehosp Emerg Care. 2005;9(2):144–155.
9. Bobrow BJ, Clark LL, Ewy GA, et al. Minimally interrupted cardiac resuscitation by emergency medical services for out-of-hospital cardiac arrest. JAMA. 2008;299(10):1158–1165.
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>> Suction assembled & operational
>> Laryngoscope assembled & checked
>> ET tube & Stylet checked, ready & lubricated
>> Correct size King Airway selected & out
>> Waveform capnography attached to monitor & active
>> Colometric C02 detector ready
>> Optional: esophageal detection device out
>> Stethoscope ready
>> Thomas tube holder out
This article originally appeared in October 2011 JEMS as “Avoiding Pitfalls: How to handle prehospital airway management challenges.”