I recall early in the pandemic being called to the bedside to examine an acutely decompensating patient with COVID-19. This was a 33-year-old, previously healthy woman, admitted to the medical ICU with hypoxemic respiratory failure requiring mechanical ventilation and undergoing treatment for severe acute respiratory distress syndrome (ARDS). I quickly realized she was seconds away from an arrest. As I examined her, one thing caught my eye. Her airway pressures had skyrocketed over the past few minutes. Could it be? I thought to myself as I reached for the ultrasound that confirmed my suspicions, tension pneumothorax. One emergent needle decompression and chest tube later and she survives, only to die a week later from overwhelming hypoxemia.
As we reflect on these past 26 months, we recall that caring for the critically ill patient with COVID-19 has posed numerous challenges. One challenge was the overwhelming incidence of the so-called “barotrauma-related complications.” However, we also recall seeing many patients develop such complications while receiving supplemental noninvasive forms of respiratory support. Perhaps, this is in agreement with prior literature that specifically discusses the presence of air outside the tracheobronchial tree and how it does not always correlate with high airway pressure and high tidal volumes, refuting the argument that these complications always fall under the umbrella of barotrauma. We will discuss these complications and attempt to shed light on the potential variables associated with their development.
Courtesy ACCP
Dr. Hafsa Abdulla
The development of pneumothorax is a well-recognized complication associated with ventilator-dependent ARDS thought to be a form of barotrauma, with some reports indicating an incidence of 48.8% (Gattinoni L et al. JAMA. 1994;271[2]):1772-9) and a significantly increased mortality rate compared with postprocedural pneumothorax in the ICU (Chen K et al. Chest. 2002;122[2]:678-83). The incidence of such complication in COVID-19-related ARDS is significantly higher than in ARDS from other causes (Belletti A et al. Crit Care Med. 2022;50[3]:491-500), with a mortality rate approaching 100% (Chong WH et al. Heart Lung. 2021;50[5]:599-608).
So why are patients with COVID-19 developing these complications at a higher rate? When we examine the literature, we note that Leisman and colleagues (Am J Respir Crit Care Med. 2022;205[5]:507-19) describe higher baseline markers of alveolar damage, including RAGE (receptor for advanced glycation end-products) in mechanically ventilated patients with COVID-19 vs patients requiring mechanical ventilation for other causes. This poses a question that perhaps one of the main reasons patients with COVID-19 ARDS are at an increased risk for developing certain complications, such as pneumothorax, is inherent to the unique type of alveolar injury sustained with the infection. The authors also note that alveolar markers of injury had moderate to poor discrimination for invasive ventilation early in the disease and diminished over time in both ventilated patients receiving lung protective ventilation strategy and those spontaneously breathing. Likewise, this important finding suggests that the development of pneumothorax in patients with COVID-19 may not be entirely related to barotrauma.
Another phenomenon worth investigating is the development of pneumomediastinum and subcutaneous emphysema, with a reported seven-fold increased risk of development in patients with COVID-19. Lemmers and colleagues (ERJ Open Res. 2020;6[4]:00385-2020) found no statistically significant difference in PEEP, plateau pressure, ratio of tidal volume to ideal body weight, or compliance between patients who developed this complication and those who did not, again, signifying that perhaps there is more to the story here.
Belletti and colleagues (J Cardiothorac Vasc Anesth. 2021;35[12]:3642-51) published an article examining the predictors of pneumothorax and pneumomediastinum in patients with COVID-19. The authors found that the time from symptom onset to intubation and the total bilirubin level were the only two significant predictors for the development of these complications. They explain that longer time from symptom onset to intubation likely increased the risk for self-induced lung injury, inflammation, and fibrosis, contributing to the development of such complications. It is important to note that the authors did not find a significant difference in the ventilation parameters between patients who developed pneumothorax/pneumomediastinum and those who did not.
In our institute, we examined a total of 102 patients admitted to the ICU with COVID-19 ARDS over a 3-month period from March 2020 to May 2020. We identified a total of 36 patients who developed pneumothorax, pneumomediastinum, and/or subcutaneous emphysema. We compared these subjects to age- and gender-matched control subjects. Higher age was associated with an increased risk of development of these complications, whereas the presence of diabetes mellitus, hypertension, and chronic kidney disease at baseline was associated with lower risk. This translated into lower mSOFA scores in our subjects as opposed to the control subjects mainly due to higher creatinine levels at baseline in the control group, skewing our data and indicating that some predictive criteria may not reflect the underlying disease severity and risk for development of such complications. In analyzing our ventilator data and comparing the subjects to the control group, we found no differences in mode of ventilation, set tidal volumes, or PEEP levels between the two. The subjects had significantly higher peak airway pressures, lower compliance, and longer ventilator days. Intubation was needed significantly earlier in the subjects compared with the control group with a median of 2 days vs 6 days from admission. Our data are in concordance with prior published reports and are set to be presented in abstract form this May.
COVID-19 remains a challenging disease with the potential for morbid outcomes. As we phase out of the pandemic and move into an epidemic, future research direction will likely focus on some of the more unusually common complications, such as the ones presented here.
Dr. Abdullah is with the Henry Ford Health System, Detroit, Michigan.