Noninvasive Ventilation: Options and Cautions for Patients with COVID-19

Doug Brunk

September 21, 2020

Early on in the COVID-19 pandemic, clinicians intubated many patients with respiratory insufficiency because of concern for aerosolization with other methods.

"We were concerned that, if we put them on high-flow nasal cannula or a noninvasive ventilation, that we would create aerosols that would then be a risk to clinicians," Meghan Lane-Fall, MD, MSHP, FCCM, said at a Society for Critical Care Medicine virtual meeting called COVID-19: What's Next. "However, we've gotten much more comfortable with infection control. We've gotten much more comfortable with controlling these aerosols, with making sure that our clinicians are protected with the appropriate protective equipment. We've also realized that patients who end up becoming intubated have really poor outcomes, so we've looked at our practice critically and tried to figure out how to support patients noninvasively when that's possible."

Respiratory Support Options

According to Dr. Lane-Fall, an associate professor of anesthesiology and critical care at the University of Pennsylvania, Philadelphia, there are two basic types of respiratory support in patients with moderate, severe, or critical COVID-19: noninvasive and invasive. Noninvasive options include CPAP or BiPAP which can be delivered through nasal pillows, masks, and helmets, as well as high-flow nasal oxygen. Invasive options include endotracheal intubation, tracheostomy, and extracorporeal membrane oxygenation (ECMO), usually the veno-venous (VV) form. "But it's uncommon to need VV ECMO, even in patients who have critical COVID-19," she said.

Dr Meghan Lane-Fall

Factors that favor noninvasive ventilation include stably high oxygen requirements, normal mental status, ward location of care, and moderate to severe COVID-19. Factors that favor invasive ventilation include someone who's deteriorating rapidly, "whose oxygen requirements aren't stable or who is cardiopulmonary compromised," said Dr. Lane-Fall, who is also co–medical director of the Trauma Surgery Intensive Care Unit at Penn Presbyterian Medical Center, also in Philadelphia. Other factors include the need for other invasive procedures such as surgery or if they have severe to critical COVID-19, "not just pneumonia, but [illness that's] progressing into [acute respiratory distress syndrome]," she said.

Indications for urgent endotracheal intubation as opposed to giving a trial of noninvasive ventilation or high-flow nasal oxygen include altered mental status, inability to protect airway, copious amounts of secretions, a Glasgow Coma Scale score of less than 8, severe respiratory acidosis, hypopnea or apnea, shock, or an inability to tolerate noninvasive support. "This is a relative contraindication," Dr. Lane-Fall said. "I've certainly talked people through the BiPAP mask or the helmet. If you tell a patient, ‘I don't want to have to put in a breathing tube; I want to maintain you on this,' often they'll be able to work through it."

Safety Precautions

Aerosolizing procedures require attention to location, personnel, and equipment, including personal protective equipment (PPE), said Dr. Lane-Fall, who is an anesthesiologist by training. "When you are intubating someone, whether they have COVID-19 or not, you are sort of in the belly of the beast," she said. "You are very exposed to secretions that occur at the time of endotracheal intubation. That's why it's important for us to have PPE and barriers to protect ourselves from potential exposure to aerosols during the care of patients with COVID-19."

In February 2020, the non-for-profit Anesthesia Patient Safety Foundation published recommendations for airway management in patients with suspected COVID-19. A separate guidance was published the British Journal of Anaesthesiology based on emergency tracheal intubation in 202 patients with COVID-19 in Wuhan, China. "The idea here is that you want to intubate under controlled conditions," said Dr. Lane-Fall, who is an author of the guidance. "You want to use the most experienced operator. You want to have full PPE, including an N95 mask, or something more protective like a powered air purifying respirator or an N95 mask with a face shield. You want the eyes, nose, and mouth of the operator covered completely."

CPR, another aerosolizing procedure, requires vigilant safety precautions as well. "We struggled with this a little bit at our institution, because our inclination as intensivists when someone is pulseless is to run into the room and start chest compressions and to start resuscitation," Dr. Lane-Fall said. "But the act of chest compression itself can create aerosols that can present risk to clinicians. We had to tell our clinicians that they have to put on PPE before they do CPR. The buzz phrase here is that there is no emergency in a pandemic. The idea here is that the good of that one patient is outweighed by the good of all the other patients that you could care for if you didn't have COVID-19 as a clinician.

"So we have had to encourage our staff to put on PPE first before attending to patients first, even if it delays patient care. Once you have donned PPE, when you're administering CPR, the number of staff should be minimized. You should have a compressor, and someone to relieve the compressor, and a code leader, someone tending to the airway. But in general, anyone who's not actively involved should not be in the room."

Risks During Extubation

Extubation of COVID-19 patients is also an aerosolizing procedure not just because you're pulling an endotracheal tube out of the airway but because coughing is a normal part of extubation. "We've had to be careful with how we approach extubation in COVID-19 patients," Dr. Lane-Fall said. "Ideally you're doing this in a negative pressure environment. We have also had to use full PPE, covering the eyes and face, and putting on a gown for precaution."

Reintubation of COVID-19 patients is not uncommon. She and her colleagues at Penn Medicine created procedures for having intubators at the ready outside the room in case the patient were to decompensate clinically. "Another thing we learned is that it's useful to do a leak test prior to extubation, because there may be airway edema related to prolonged intubation in these patients," Dr. Lane-Fall said. "We found that, if a leak is absent on checking the cuff leak, the use of steroids for a day or 2 may help decrease airway edema. That improves the chances of extubation success."

Strategies for Aerosol Containment

She concluded her remarks by reviewing airway control adjuncts and clinician safety. This includes physically isolating COVID-19 patients in negative pressure rooms and avoiding and minimizing aerosols, including the use of rapid intubation, "where we induce anesthesia for intubation but we don't bag-mask the patient because that creates aerosols," she said. The Anesthesia Patient Safety Foundation guidelines advocate for the use of video laryngoscopy so that you can visualize the glottis easily "and make sure that you successfully intubate the glottis and not the esophagus," she said.

A smart strategy for aerosol containment is to use the most experienced laryngoscopist available. "If you are in a teaching program, ideally you're using your most experienced resident, or you're using fellows or attending physicians," Dr. Lane-Fall said. "This is not the space for an inexperienced learner."

Another way to make intubation faster and easier in COVID-19 patients is to use an intubation box, which features a plexiglass shield that enables the intubator to use their hands to get in the patient's airway while being protected from viral droplets generated during intubation. The box can be cleaned after each use. Blueprints for an open source intubation box can be found at http://www.intubationbox.com.

Expert View on Aerosol Containment in COVID-19

While there is a dearth of evidence from controlled trials, recommendations mentioned in this story are based on the best available evidence and are in agreement with guidelines from several expert groups," said David L. Bowton, MD, FCCP, FCCM, of the department of anesthesiology at Wake Forest Baptist Health in Winston-Salem, NC.

"The recommendation of Dr. Lane-Fall's that is perhaps most controversial is the use of an intubation box. Multiple designs for these intubation/aerosol containment devices have been proposed, and the data supporting their ease of use and efficacy has been mixed [See Anaesthesia 2020;75(8):1014-21 and Anaesthesia. 2020. doi: 10.1111/anae.15188]. While bag valve mask ventilation should be avoided if possible, it may be a valuable rescue tool in the severely hypoxemic patient when used with two-person technique to achieve a tight seal and a PEEP valve and an HME over the exhalation port to minimize aerosol spread.

Dr David Bowton

"It cannot be stressed enough that the most skilled individual should be tasked with intubating the patient and as few providers as possible [usually three] should be in the room and have donned full PPE. Negative pressure rooms should be used whenever feasible. Noninvasive ventilation appears safer from an infection control standpoint than initially feared and its use has become more widespread. However, noninvasive ventilation is not without its hazards, and Dr. Lane-Fall's enumeration of the patient characteristics applicable to the selection of patients for noninvasive ventilation are extremely important. At our institution, the use of noninvasive ventilation and especially high-flow oxygen therapy has increased. Staff have become more comfortable with the donning and doffing of PPE."

Dr. Lane-Fall reported having no financial disclosures.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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