We constructed a CopperHead frame to use during aerosol-generating procedures and tested it for safety in a mannequin, healthy volunteer and critically ill patients. We found that the frame was easy to use, well received by healthcare staff, and safe during defibrillation.
The risk of aerosol generation has led to significant changes in the airway algorithm for most hospitals and clinicians taking care of patients either infected with or suspected to have COVID-19. Experts recommend avoidance of airway adjuncts such as CPAP or BiPAP that could potentially increase aerosol generation. (Figure 1A/B) One review suggested the odds ratio (OR) of aerosolization during various procedures to be as such: a) manipulation of BiPap mask = 6.2 [95%CI 2.2, 18.1], b) endotracheal intubation = 6.6 [95%CI 2.3, 18.9], c) non-invasive ventilation = 3.1 [95%CI 1.4, 6.8], d) manual ventilation = 2.8 [95%CI 1.3, 6.4], e) collection of sputum sample 2.7 [0.9, 8.2], and f) chest compressions 1.4 [95%CI 0.2, 11.2]. The use of high flow nasal cannula is controversial and aerosol generation is perceived to be minimal at flow rates < 30 L/min with OR 0.4 [95%CI 0.1, 1.7].[13, 14, 16, 22] Importantly, the exhaled air dispersion distance of these oxygen administration and ventilator support strategies could be as far as 100 cm. Many institutions advocate for securing the ETT and closing the circuit with a viral filter in place.[10-14] In addition, the Society of Critical Care Medicine (SCCM) and the Centers for Disease Control and Prevention (CDC-P) recommend performing such aerosol-generating procedures in a negative pressure room. Given the limitation in such resources, the high rate of infection in health care workers, and the fear surrounding the spread of COVID-19, it is of paramount importance to pursue all strategies to contain or minimize aerosol spread. One such method is the placement of a plastic drape over the patient, which has the potential to contain the aerosols generated by any of these procedures underneath the drape and in the space around the patient’s head. However, the safety of such a potentially oxygen-rich space that can pose a fire hazard, especially with defibrillation, is a concern.
Our experiments on both mannequin and human volunteer tests concluded that the FiO2 underneath the plastic drape increased within a few minutes but rapidly dissipated when the CopperHead frame and plastic drape were removed. The respiratory rate of the healthy volunteer is approximately half of what would be expected for a patient in respiratory distress. The oxygen consumption would likely increase in patient with hypoxia and tachypnea, perhaps resulting in lower measured FiO2.
Although our testing indicated that defibrillation while the CopperHead frame and plastic drape were in place was unlikely to cause a burn, shock, or fire, our recommendation is to remove the frame from the patient’s bed prior to delivering any shock.
At our institution, we developed a comprehensive airway algorithm to manage all inpatient airways and code blue situations with the presumption that these patients are COVID-19 positive (Figure 1A/1B). Ranging from hemodynamically unstable to cardio- or respiratory failures/arrests, we coded and intubated patients using our device. In retrospect, we demonstrated that CPR can be performed safely and effectively while the copper frame and plastic drape are in place. If needed, the drape could be moved up to the nipple line of the patient while maintaining the ability to place defibrillator pads and access the patient’s chest for effective chest compressions.
The use of the CopperHead frame, as well as other barrier devices, was found to facilitate safe endotracheal intubation as well as other procedures such as tube exchange and bronchoscopy (Table 4). Of 74 patients retrospectively analyzed, we found that 30% were indeed COVID-19 positive (Table 5). 69 (93%) of these patients were intubated in the CopperHead device and 65 (88%) were successfully intubated on the first attempt. This is comparable with data noted in the literature, both in the intensive care unit and in the operating room.  We note that all 74 of these patients did have successful airway placement. The GlideScope was the primary video assist device used in our hospital at a rate of approximately 90%. The C-MAC device and traditional direct laryngoscopy devices were also used in accordance with provider preference in different patient care areas. No practitioners who performed these procedures were documented or reported to have become infected with COVID-19.
The majority of patients were intubated for respiratory failure 37 (50%). Other reasons for intubation included respiratory distress 11 (15%), Airway protection including trauma or decreased mental status 17 (23%) and Cardiac Arrest 8 (11%). Of the 74 patients analyzed, 35 patients expired. 36 patients were extubated but this number included patients that were terminally extubated and also were counted as “died”. Other data such as sedation and paralytic choices were recorded. However, no correlations to these choices and outcomes have been made.
Finally, the CopperHead frame and plastic drape was used during extubation for our recovered patients as documented in Table 5. The setup and placement of the frame and drape was the same, including use of proper PPE. The hood was kept in place for two minutes post-extubation or until the patient stopped coughing and appeared calm.
The use of the CopperHead frame and plastic drape over the patient does not replace the need for enhanced PPE including bouffant or head covering, full eye protection, N95 mask or powered air purifying respirator, fluid-resistant gown, two sets of gloves, and shoe covers. It is strongly recommended to abide by droplet and contact precautions as per CDC recommendations.[10, 11, 25]
Our device is not a perfect solution for all settings and has its limitations. First, there is imperfect aerosol containment during removal of the frame. We do not have the data to determine the degree to which aerosolization is contained by the frame or is dispersed during frame removal. Furthermore, we have not determined the ideal time total to leave the plastic drape in place post extubation to minimize the release of these aerosols to the air, although we have adopted 2 minutes in our practice.
Additionally, it is possible aerosol particles may escape through the holes made in the plastic drape utilized by the hands of the intubating clinician and, when needed, the respiratory therapist. The plastic drapes used at our facility are fairly thin and do allow for minimal tearing to create a close fit to the arms and equipment passed through them while not sacrificing hand movement and dexterity. However, we recognize that this creates a leak to potential aerosols from inside the drape.
The partial opacity of the plastic drape may affect direct visualization of the airway. However, the drape can be promptly removed allowing for direct or fiberoptic laryngoscopy in case of an unsuccessful video-assisted laryngoscopy. Of note, multiple clinicians were able to successfully perform direct laryngoscopy with our device in place during simulation. It still remains, though, that the judgment of the intubating clinician must dictate the steps necessary to address any difficult airway situations which may include use of adjuncts such as a bougie or oxygenating airway exchange catheter (Cook Medical LLC, Bloomington IN) or the prompt removal of the CopperHead and plastic drape to perform additional maneuvers.