Around the country, clinicians in intensive care units are charged with preventing hospital-acquired infections and accidental extubations, both of which can lengthen hospital stay, increase costs, and worsen patient outcomes.
By Phyllis Hanlon
Airway management in the intensive care unit (ICU) has become increasingly complicated in recent years, due in part to the growing prevalence of obesity as well as an increasing number of patients who present with several comorbid conditions. These patients typically have difficult airways and pose a challenge for clinicians during intubation.1
An editorial2 published in The British Journal of Anaesthesia cited the importance of the 4th National Audit Project of the Royal College of Anaesthetists and Difficult Airway Society (NAP4), which examined the difficulties and potential failures when managing the airway in the ICU. NAP4 claimed the ICU to be “a place of ‘increased airway danger’” when compared to the operating room.
When intubation is necessary while the patient is in the ICU, rapidly deteriorating physical condition can further complicate attempts to manage the airway. Throughout the last couple of decades, different devices and advanced technology have brought new options to the market, including direct, indirect and video laryngoscopes, adult and pediatric flexible fiberoptic bronchoscopes and laryngeal mask airways.
Depending on the situation, airway management could involve basic or advanced techniques, including the use of supraglottic devices, intraglottic intervention or surgery. New airway visualization devices, in combination with supraglottic tubes, may offer the best option for managing the difficult airway, according to Tom McGrail, director, Clinical Services at Ambu. Four years ago Ambu bought King Systems and together the two companies and their products “…dovetail nicely with one another,” said McGrail.
Visualization and Optimizing Oxygenation
McGrail pointed out that airway visualization products, such as the King Vision VL and Ambu aScope3, facilitate intubation “primarily as an alternative to normal Mac and Miller direct laryngoscopy blades.” He said, “They give you a much greater view of what’s going on. Others in the vicinity can see what’s going on as well.”
In the case of a failed intubation, the latest airway algorithms suggest using a combination strategy of “…two geometrically different supraglottic airway devices,” according to McGrail. “Try one supraglottic device and if that doesn’t work, try another before doing a surgical airway,” he said. “The warning is don’t just try two different laryngeal masks that are virtually the same, but try two different designs (eg a laryngeal tube vs a laryngeal mask) because how they seal the airway is totally different.”
Prior to intubation, it’s critical to stabilize the patient hemodynamically by appropriate oxygenation. The OPTINIV study3 acknowledges that severe hypoxemia is one of the adverse effects related to tracheal intubation in the ICU, sometimes reaching as high as 50%. The researchers investigated the use of noninvasive ventilation (NIV)-assisted preoxygenation in combination with high-flow nasal cannula oxygen therapy (HFNC) to determine if this dual therapy would have better outcomes than NIV alone.
At the conclusion of the study, the authors did not have definitive answers regarding the advantages of NIV versus HFNC alone, but will continue to evaluate the effects of the combination therapy on intubation-related complications in the ICU. However, they did emphasize the importance of anticipating hypoxaemia to forestall the development of other adverse effects. “Severe hypoxaemia can lead to cardiac arrest, neurological damage or multiple organ failure,” the authors wrote.
McGrail indicated that it is accepted practice to always pre-oxygenate in the operating room before intubation. “[In the operating room] you have the time and you can prolong the allowable apneic time to make it safer to intubate. That said, I think that people often ignore the obvious when you go to emergency situations outside the OR where the patient is desaturating and going downhill fast. You think the faster you can get a tube in, the better off the patient will be,” McGrail said. “But stop to think. Is there something I can do to prevent desaturation during intubation attempts? Perhaps putting a nasal cannula in and really flooding the airway with oxygen during intubation makes sense.”
Reducing Risk of Infection
The risk of infection has always been a concern in every hospital department and recent reports of rampant infections has drawn more attention to the matter. Some industry experts prefer single-use, disposable equipment as a better option for patient safety. “There is more and more evidence coming out that it’s extremely difficult to clean and disinfect and sterilize reusable bronchoscopes between uses, especially the working channel. You have to flush it out and there can be biofilm that forms that’s virtually impossible to clean,” said McGrail. “Manufacturers realize this and have to provide adequate cleaning and disinfection instructions. Even if you follow them though, they aren’t always totally effective.”
For instance, if a flexible scope is used on a patient with a known infection, such as hepatitis or mad cow disease, which carry difficult-to-kill organisms, an epidemic could erupt, according to McGrail. “There has been recognition that if a patient has a difficult airway, you have to use a bronchoscope and throw it away. Having a disposable bronchoscope like the Ambu aScope3 solves that problem,” he said.
McGrail pointed out that training for those who use a video laryngoscope, like King Vision “…absolutely has to complement the training by the individuals’ organizations.” For example, paramedics are already trained to intubate using standard direct laryngoscopy, and although all anatomy is the same, determining how to insert the blade and direct the tube toward the tracheal opening requires additional training with VL, he added.
Ambu offers both a channeled blade (no stylet needed) and non-channeled blade that requires use of a stylet. “But because the tube delivery to the trachea is indirect going around the corner with King Vision, rather than direct line of sight with normal laryngoscopy, it requires some getting used to,” he said. “We do in-service and training on manikins, hang out in the operating room during initial intubations and have created videos.”
The Society for Airway Management (SAM) has focused on airway management as one of its primary goals and plans to enhance patient safety through technology, training and collaboration with other industry associations. While the organization expresses concerns about training, Felipe Urdaneta, MD, vice president for SAM, pointed out that inconsistencies in training, as well as availability of equipment, exist throughout the industry. The lack of standardization raises great concern, he added.
“Different bodies have different methods. For instance, the ASA (American Society of Anesthesiologists) has its own rules, separate from SAM’s,” he said. “There is no unification at the present time. It will be very difficult to bring everyone together. Great Britain is more unified because they only have one professional organization. In North America, we have several organizations giving their own opinion.”
In an effort to provide more education to those in the industry and recognizing that airway management can be very challenging for the uninitiated, SAM offers a number of training courses at its annual conference that can be very helpful, according to Urdaneta.
Urdaneta noted that in recent years several new devices and techniques have come to market that might have a significant impact on airway management. One technique that has been considered in recently is ultrasonography. “It can predict a difficult airway prior to intubation,” he said, adding that it can also determine placement of an endotracheal tube (ETT) and appropriate ventilation following intubation.
Michael Kristensen, MD, has researched the technique extensively and cited several advantages to using ultrasound to manage the difficult airway. In a 2016 study,4 he and his colleagues examined the technique and determined there are many roles for ultrasound in “clinical decision-making, intervention and management of the upper and lower airways.” For instance, ultrasound can identify the cricothyroid membrane and other tracheal structures when clinical staff is unable to do so by palpation. According to the study, ultrasonography can be a “primary diagnostic approach” in confirming intraoperative pneumothorax and can determine treatment “of interstitial syndrome, consolidation, atelectasis and effusion.” Kristensen emphasized though that using ultrasound at the point of care requires significant training.
Urdaneta added that ultrasound might be able to guide the clinician during intubation attempts, ensuring proper insertion of the tube into the trachea. “It can also detect when there are gastric juices present, which might cause aspiration,” he said.
Another interesting development in the field of airway management is the use of computerized facial analysis to determine the ease or difficulty of intubation, according to Urdaneta. “There is good data to support this, although it’s not as widespread yet. It needs more research, but looks promising,” he said.
A 2011 study5 created a computer model that evaluated patients’ anatomy during bedside airway to predict difficult intubation before getting anesthesia. Eighty male patients were divided into two groups; both groups had 20 easy and 20 difficult intubations. Special software analyzed each subject’s face and created an algorithm. The results showed that a model consisting of “three facial parameters and thryomental distance” was able to correctly identify 70 of the 80 patients who might have a difficult airway. The authors concluded that computerized facial analysis accurately classified “easy versus difficult intubation” and outperformed other, more popular clinical tests.
More recently, Tufts Medical Center launched a study on facial analysis in May 2012; final data collection is expected by June 2017. This trial aims to further the work of Connor and Segal, who conducted the 2011 study, in using three digital photographs of the head and neck to predict the ease or difficulty of intubating a patient.
Studies have shown the risk of complication associated with intubation, particularly in the ICU. Several factors, not typically experienced in the operating room, challenge clinicians in their attempt to successfully intubate. In a 2015 commentary,6 Stephen Lapinsky, MD, suggested tracking all complications in an effort to enhance the quality improvement process during intubation.
Phyllis Hanlon is a contributing writer to RT. For further information, contact [email protected]
- DeJong A, Molinari N, Pouzeratte Y, et al. “Difficult intubation in obese patients: incidence, risk factors, and complication in the operating theatre and in intensive care units.” Br J Anaesth 2015; 114:297-306.
- Higgs A, Cook TM, McGrath BA. “Airway management in the critically ill: the same, but different.” Br J Anaesth 2016, 1-4. doi: 10.1093/bja/aew055.
- Jaber S, Molinari N, DeJong A. “New method of preoxygenation for orotracheal intubation in patients with hypoxaemic acute respiratory failure in the intensive care unit, non-invasive ventilation combined with apneic oxygenation by high flow nasal oxygen: the randomized OPTINIV study protocol.” BMJ Open 2016; 6:e011298. doi: 10.1136/bmjopen-2016-011298.
- Kristensen M, Teoh WH, Graumann O, Laursen CB. “Ultrasonography for clinical decision-making and intervention in airway management: from the mouth to the lungs and pleurae.” Insights Imaging. 5:253-279. doi: 10.1007/s13244-014-0309-5.
- Connor CW, Segal S. “Accurate classification of difficult intubation by computerized facial analysis.” Anesth Analg. 2011 Jan;112(1):84-93. doi: 10.1213/ANE.0b013e31820098d6. Epub 2010 Nov 16.
- Lapinsky SE. “Endotracheal intubation in the ICU.” Critical Care 19:258. doi: 10.1186/s13054-015-0964-z