Patients with COVID-19 pneumonia have been found to require increased mechanical ventilation
4. Also, the need for extended periods of positive endexpiratory pressure (PEEP) in patients with COVID-19 pneumonia led to extended periods of intubation
8.
It was considered to delay performing tracheotomy to mitigate the infection risk to physicians and allied healthcare personnel during the COVID-19 pandemic, and compared to the prepandemic period, the intubation time of patients without tracheotomy was reported to have increased by 10 days on average 9. Allgood et al. 4 have reported the median ventilation time of COVID-19 patients as 17 days, while Scholfield et al. 5 have reported it as 28 days. In our study, all of our patients were followed up as intubated, and the median number of intubation days was 15.75±7.8.
The significance of damage depth was found to be an important factor in developing subglottic stenosis 10. The damage on a mucosal and submucosal level usually appears to heal in a normal way. However, the damage in lamina propria, perichondrium, and cartilage heals in the form of stenosis in the subglottic region 11,12. The traumas on the deep level stimulate the fibroblasts in lamina propria 13. Fibroblasts in the lamina propria produce inflammatory cytokines such as collagen and TGF-beta. This stimulates mucosal fibrosis 14. Mucosal damage is observed as a result of the subglottic region's traumatization due to the intubation tube's movement during the intubation. One of the factors that cause mucosal damage is cuff pressure. Increased cuff pressure causes mucosal damage due to its mucosal contact 15,16. The rate of tracheal complications in coronavirus patients, such as postintubation subglottic stenosis, has been reported to increase as a result of different combinations of increased proinflammatory cytokines, microvascular damage caused by increased thrombosis, increased viral load in the airway mucosa, mucosal atrophy caused by steroids used in the treatment 17.
Subglottic stenosis treatment algorithm is questionable, and criteria that define the inefficacy of endoscopic laser surgery with balloon dilatation method and the requirement of surgical intervention have yet to be defined conclusively. Christopher et al. 18 have reported the median number of preresection endoscopic laser surgery with balloon dilatation treatments as 2.2. in patients where laser surgery with balloon dilatation intervention is not effective and tracheal resection is required. Scholfield et al. 5 have reported that one of the three patients who developed subglottic stenosis during COVID-19 responded to laser surgery with balloon dilatation treatment; the other two patients did not benefit from the laser surgery with balloon dilatation treatment and performed the resection of the stenotic segment and end-to-end anastomosis operation. Our study found the median number of laser surgery with balloon dilatation treatments to be 2.25±0.95. No open surgery was required in any of the patients. The preo-perative stenosis grading was Stage 3 in three of the patients and Stage 2 in one of them, while the postoperative stenosis grading was Stage 1 in all of them. The median time since the last laser surgery with balloon dilatation operation was 10.75 ± 2.62 months, and the patients continued to live normally without any shortness of breath.
COVID-19 infection can cause various complications following the damage it causes in the tissues. Patients intubated due to pneumonia developing in the lungs can develop subglottic stenosis. Despite our limited number of patients, we think that laser surgery and balloon dilatation are effective and safe methods to treat subglottic stenosis that develops after the COVID-19 infection.