Humidified Nebulizer to Prevent Tracheostomy Cannula From Obstruction During the COVID-19 Pandemic

Article information

J Korean Soc Laryngol Phoniatr Logop. 2024;35(2):58-64

Publication date (electronic) : 2024 August 30

doi : https://doi.org/10.22469/jkslp.2024.35.2.58

Ki Ju Cho¹, Min Ji Kim², Yoon Se Lee^,2, Minsu Kwon², Yonghan Kim², Young Ho Jung², Seung-Ho Choi², Soon Yuhl Nam²

¹Department of Otorhinolaryngoloy, Myongji Hospital, Hanyang University Medical Center, Goyang, Korea

²Department of Otolaryngology-Head and Neck Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea

Corresponding Author Yoon Se Lee, MD, PhD Department of Otolaryngology-Head and Neck Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea Tel +82-2-3010-3690 Fax +82-2-3010-3710 E-mail yselee@amc.seoul.kr

Received 2024 May 7; Revised 2024 August 8; Accepted 2024 August 9.

Abstract

INTRODUCTION

Proper management of the tracheostomy cannula (T-cannula) is required to secure the airway for patients who can breathe only through it. Tracheostomy is usually indicated for prolonged ventilation, prevention of aspiration, and relieving airway obstruction [1]. However, tracheostomy may cause complications such as bleeding, cannula obstruction, tube shifting, emphysema, wound infection, and laryngeal paralysis [2]. Among them, abrupt cannula obstructions may lead to hypoxic injury and even to death. Improper management of T-cannula is one of the risk factors to cause these complications. Frequent and gentle suction performed by trained personnel is required to prevent obstruction and for their adequate management. This depends on time and personal factor, which are not always available when taking care of the patients with T-cannula.

In addition to training the patients and guardians to take care of cannula, there are couple of ways to avoid obstruction. Double lumen cannula may prevent obstruction by frequent or daily cleansing the inner cannula of double lumen, which help to check and maintain the patency of the cannula [3]. However, these specific types of cannula are not always available to all patients and inner cannula can also be obstructed by mucous plug or crust. Humidified nebulizers containing mucolytics have been used to prevent crust formation or plugging of endotracheal tube and tracheostomy tubes [4,5]. Due to the risk of virus transmission by aerosols during the coronavirus disease 2019 (COVID-19) pandemic, their use has been limited in public space and nonquarantine intensive care units (ICU) [6]. To skip regular nebulizing the cannula due to fear of aerosol transmission may increase the risk of unexpected obstruction of T-cannula. The inadequate management of T-cannula has become a greater concern because of emergent T-cannula exchange caused by endotracheal crust. It would also be difficult for care-givers to avoid the possibility of exposure to the aerosol during frequent suction through T-cannula, which may increase the risk of viral transmission. These concerns have not entirely evaluated elsewhere. The benefits and risks of a nebulizing method of tracheostomy tube management during the COVID-19 pandemic should be investigated. In this study, the predisposing factors of T-cannula obstruction was analyzed and the protective role of nebulizers to prevent T-cannula obstruction was reviewed. Thus, we aimed to suggest a tracheostomy tube management strategy through this analysis.

MATERIALS AND METHOD

RESULTS

Among the enrolled 226 patients who underwent tracheostomy, cannula obstruction was found in 62 patients (27.4%) (Table 1). In both groups, there was a male predominance (n=155, 68.6%). The proportion of male patients in obstruction group (n=40, 25.8%) was similar to in non-obstruction group (n=115, 74.2%, p=0.550). Average ages of obstruction group was slightly older than non-obstruction group, which was not significantly different (p=0.570). Median follow-up period was 13.8 months. Duration of tracheostomy in obstruction group was about 10 months after tracheostomy, which was slightly shorter than non-obstruction group (15 months) (p=0.047). Most of tracheostomy tube obstruction occurred usually within 2 weeks after tracheostomy (n=39, 62.9%) while 23 patients (37.1%) occurred more than 2 weeks after tracheostomy.

Table 1.

Univariate analysis of risk factors of tracheostomy cannula obstruction (n=226)

Incidence of obstruction was higher in ex-smoking group (38.0%) and current smoking group (41.7%) than never smoking group (16.8%) (p=0.022 and 0.018, respectively). Smoking history, body weight, and BMI were not related to the incidence of tracheostomy obstruction. The patient with worse performance status score (≥3) presented higher incidence of obstruction rate (30.7%) than better score (≤2) (p=0.091). Among the medical comorbidities, the patients with pulmonary diseases (42.2%) presented higher incidence of tracheostomy obstruction than the patients without pulmonary diseases (27.8%, p=0.031). Nebulized patients presented lower incidence of obstruction (12.3%) than non-nebulized patients (45.2%, p<0.001) (Fig. 1). In multivariate analysis, both ex-smoking (hazard ratio [HR]=1.962, 95% CI=0.418–6.218, p=0.033) and current smoking history (HR=2.108, 95% CI=0.246–10.041, p=0.027) increased the risk of cannula obstruction (Table 2). Pulmonary diseases affected risk of cannula obstruction (HR=1.740, 95% CI=0.311–7.312, p=0.038). Nebulizer decreased risk of obstruction by about 4.6 folds (p<0.001). There were no reports of respiratory virus transmission and safety issues in nebulized patients.

Fig. 1.

Risk of tracheostomy tube obstruction based on the use of a nebulizer (Kaplan–Meier curves).

Table 2.

Multivariate analysis of risk factors of tracheostomy cannula obstruction

Next, we analyzed the risk factors related to mortality in this group (Table 3). Gender, duration of tracheostomy, smoking history, body weight, eastern cooperative oncology group performance status score, DM, liver diseases, and nebulizer usage were not related to death (Fig. 2). Average age of alive patients (60.5±17.2 years) was younger than dead patients (66.1±10.4 years) (p=0.041). BMI was slightly lower in alive patients than in dead patients (p=0.053). Pulmonary diseases were associated with mortality rate (p=0.129). Hypertension tended to be associated with mortality rate (p=0.065). In multivariate analysis, current smoking history (HR=2.375, 95% CI=0.175–17.803, p=0.093) increased the risk of death compared to never smoker. And pulmonary diseases (HR=2.911, 95% CI=1.538–15.508, p=0.001) increased the risk of death. Age and hypertension were probably related to the death rate (Table 4).

Table 3.

Univariate analysis of risk factors of survival outcome of enrolled patients

Fig. 2.

Survival curve according to the use of a nebulizer (Kaplan– Meier curves).

Table 4.

Multivariate analysis of risk factors of overall survival outcome

DISCUSSION

One of the serious complications of tracheostomy is obstruction of T-cannula which leads to frequent suction, respiratory difficulty, and even death. Humidification of the airflow through T-cannula may prevent obstruction in addition to frequent suction performed by care-givers. Currently, as the global pandemic of the COVID-19 was widely spread, isolation of the patients in ward is recommended to decrease the possibility of viral transmission through the aerosol generated during coughing, suction, and even humidification with nebulizer [8,9]. Since the first COVID-19 positive patient diagnosed in South Korea on January 20, 2020 [10], the strenuous effort to reduce the possibility of viral spread has been ongoing. In proportion to the increasing necessity of tracheostomy for the patients who requires ventilator or persistent oxygen support, significance of safe management of T-cannula cannot be overlooked. Before the COVID-19 pandemic, our institute used nebulization to prevent cannula obstruction. However, during the pandemic, the hospital’s infection control team strictly regulated nebulization due to the risk of virus transmission through aerosols generated by the process. Following these regulations, we observed an apparent increase in the incidence of T-cannula obstructions compared to the pre-pandemic period. This observation prompted us to investigate the role of nebulization in preventing T-cannula obstruction.

In this study, we found that tracheostomy tube obstruction, rather than aerosol generation, is one of the early complications of tracheostomy and can be life-threatening. The most common cause of obstruction is mucus or crust formation in the trachea or tube. Therefore, proper humidification and suction are required to prevent this [11]. Cannula obstruction due to mucus, like airway obstruction, causes serious complications such as cardiovascular instability, atelectasis, pulmonary edema, and brain damage. Hence, prompt detection and treatment are necessary [7]. We also found that smoking history and pulmonary diseases increased the risk of cannula obstruction and nebulizer ameliorated the risk of obstruction. Nebulizer-related spread of COVID-19 was not found. Considering mortality rate of the enrolled patients was affected by the smoking history and pulmonary diseases, nebulizer with mucolytics may have a safe role to prevent T-cannula from obstruction without increasing the mortality rate.

Tracheostomy is usually considered for patients requiring invasive mechanical ventilation over a prolonged intubation period (longer than 7–10 days in the ICU) [12,13]. In proportion to the increasing number of patients requiring ICU care, the incidence of tracheostomy has been increasing during the pandemic [14]. Our tertiary hospital has taken care of COVID-19 patients who need intensive care with prolonged ventilator care. Around 20% of COVID-19 patients progress to the critical stage of the disease and about 5% need attention in the ICU [15]. In proportion to the increment of tracheostomy, T-cannula management cannot be overemphasized. With the fear of outbreak through aerosol transmission nebulizer use to rinsing the mucous plug was restricted. In this study, there was no viral transmission originated from the patients with T-cannula who underwent nebulizer with mucolytics on quarantine activities. Instead, the incidence of cannula obstruction was increased without the use of nebulizers compared to nebulizer users. Viral spread through aerosol to healthcare staff and other patients was not significantly reduced by avoiding the use of nebulizers. Ensuring minimal exposure and risk to staff performing the procedure will be of paramount importance. Nebulization or suction with a Foley catheter can be conducted to remove mucus from the cannula, and in the case of a large, hard crust, the endotracheal tube or tracheostomy tube should be substituted [16]. These approaches are generally used when the emergency airway protection team is alerted. Current guidelines for tracheostomy care recommend the use of full personal protective equipment (PPE) for all aerosol-generating procedures; these PPE include a filtering facepiece 3 mask, eye protection, fluid-repellent disposable surgical gown, and gloves [17]. By reducing the incidence of mucous plug-induced T-cannula obstruction, this manpower-consuming care would be decreased.

Smoking history and pulmonary diseases are relevant to the thick mucous production. Considering that these two factors increased the risk of T-cannula obstruction, resolution of mucous plug is necessary to prevent T-cannula obstruction. In this study, we confirmed that the comparative risk of tracheostomy cannula obstruction was significantly lower in patients using a nebulizer. Previous studies have shown the effectiveness of humidification in preventing tracheostomy cannula obstruction, which is in line with our results [4]. However, notably, the effects of humidification were compared in a special situation with various limitations in the COVID-19 period. The underlying disease and the patient’s performance status were also checked to see if there were any other causative factors. Additionally, tube obstruction frequently occurred within 1 week after tracheostomy. This may imply that blood clot formation is another contributing factor to the T-cannula obstruction, which can occur during or 1 week after the tracheostomy. Obstruction was attributed to mucus mixed with blood clots produced immediately after tracheostomy. In addition, a mucous plug may be formed due to the dry hospital ward environment passing through the tracheostomy tube. Therefore, we should pay more attention to the management of the cannula in patients with T-cannula especially during the COVID-19 pandemic.

Corona virus has been known to persists in the air 3 hours after being aerosolized in a laboratory environment, airborne transmission is possible [14]. Because of the latent virus, using a nebulizer in a hospital room with a lot of particles can be harmful. In this study, we found no evidence for such spread of COVID-19 when a nebulizer was used in an isolation room; however, if this is not possible, it might be more cost-effective to use it under the supervision of medical staff in a multi-person room with a confirmed negative COVID-19 test. We initially used nebulizers in isolated areas during the early COVID-19 pandemic. After confirming that there was no viral transmission, we began using nebulizers in rooms separated by curtains, with other patients required to wear face masks. This level of precaution was deemed sufficient to prevent viral transmission through aerosols generated by nebulization. Complete isolation would not be necessary to prevent viral spread to use nebulizer. In the COVID-19 pandemic, it is important to ensure the safety of medical staff while also improving the patient’s prognosis through appropriate interventions. This is expected to be supplemented as more data are obtained in the future.

This study has some limitations. This study was a retrospective study which evaluated the limited numbers of patients. When evaluating the risk factors of T-cannula obstruction, disease entities, including pulmonary disease, hypertension, DM, and liver diseases, were so diverse to confine the disease relevant to T-cannula obstruction. Also, pulmonary diseases contained various types respiratory failures with or without ventilator care regardless of COVID-19. Considering that there were some risk factors in multivariate analysis, prophylactic role of nebulizer was elucidated in this study. As this study was conducted during quarantine, there appears to be insufficient evidence to generalize the findings to all clinical situations and cost-effectiveness aspects. If we confined the cases of COVID-19, safety of nebulizer from viral transmission would be more clear, which should be evaluated in the future.

CONCLUSION

Nebulization should be recommended to prevent tracheostomy cannula obstruction when used in isolation, including patient separation with a curtain, in a single or isolated room, and with other patients wearing a mask. The use of the nebulizer decreased the risk of cannula obstruction without affecting the mortality rate. It will also help care-givers to avoid from viral transmission. In a real world setting, this would benefit safe patient management of those undergoing tracheostomy.

Article information Continued