Discussion
In this study, 90% of patients intubated as part of COVID-19 management across the ROI who were referred to SLT presented with new onset PED based on oral intake status. Over half (59%) required tube feeding based on SLT assessment and over a third were unable for any nutrition orally post-extubation. This high rate of PED compares with recent research (3, 4). Post-extubation oral intake status was associated with length of ICU stay and hospital stay duration in this study.
There was a threefold increase in impact on oral intake status with proning in this study. Lower cranial nerve paralysis and oropharyngeal oedema have previously been linked to proning, and cranial nerves IX to XII are hypothesised to be affected by proning (7, 23). Pre-existing respiratory disease was also identified as a predictor of PED in this study. Adults with respiratory disease may already have altered respiratory swallow coordination, which could be exacerbated post-extubation. There was approximately a 6% increase in the relative odds of oral intake status change per year of age in this study. Older people may have a pre-existing presbyphagia, which pre-disposes them to PED. Furthermore, frailty and sarcopaenia may also be prevalent amongst older people, which could contribute towards PED. In contrast to previous research (5), duration of intubation was not predictive of oral intake status in this study. This may be due to the fact that patients with tracheostomy were not excluded in this study, as researchers aimed to capture all adults with COVID-19 post extubation. Additionally, prolonged intubation duration with COVID-19 may explain contrasting findings to previous PED research.
There was a tenfold increase in impact on voice quality for those with intubation injury, which aligns with previous research (15). This highlights the importance of post-extubation endoscopy to evaluate vocal cord function in the ICU setting. Those with a history of respiratory disease were at threefold risk of impact on voice quality. Dysphonia is prevalent in adults with COPD which is due, in part, to altered pulmonary function (24). This alteration may be exacerbated post-extubation, which may negatively impact on voice. In contrast to previous research (14), endotracheal cuff pressure was not associated with post-extubation dysphonia in this study.
The number of adults receiving SLT rehabilitation during hospital stay appeared low in this study and some adults did not receive dysphagia and dysphonia intervention when indicated. Concerns regarding aerosol generated procedures as well as lack of instrumental evaluations may have influenced the amount and type of intervention being offered during the first pandemic wave (16). Other influencing factors may be access to personal protective equipment, SLT services in ICU settings across ROI, and local dysphagia training.
The rates of persistent dysphagia and dysphonia at hospital discharge mirrors previous COVID-19 research (3, 4). These subgroups may require long term rehabilitation due to ICU acquired weakness, post-intensive care syndrome (PICU) or neurological deficits. These figures are clear evidence that speech and language therapists should be core members of outpatient multidisciplinary COVID-19 clinics.
Limitations to this study included missing data on oral health, delirium, grade of intubation and endotracheal tube size. Missing data was particularly difficult to access from intensive care records due to transmission risk. Patient reported outcomes would have been beneficial but not feasible post-extubation given how medically unwell this cohort were. Validated scales to measure frailty and sarcopaenia amongst adults intubated may have been useful but again this was not feasible in the context of this study.
FEES was not available in ICU settings during the first wave of the pandemic due to concerns regarding transmission risk (16). FEES provides physiological data on secretions, pharyngeal sensation and aspiration or residue. However, it could be argued that oral intake is a more meaningful outcome from the patient perspective. Nevertheless, endoscopic assessment of intubation injury would be valuable to ensure the presence and nature of laryngeal injuries are accurately identified (25).
Post-extubation dysphonia and dysphagia research is needed from future pandemic waves to establish the impact of evolving intensive care management and mutating virus variants on voice and swallowing outcomes. Post-discharge timepoints to capture longer term voice and swallowing difficulties would guide multidisciplinary service delivery in the community.
Conclusions
This study highlights the prevalence of post-extubation dysphagia and dysphonia amongst adults intubated with COVID-19. Awareness of the predictors of altered swallowing and voice quality post-extubation will promote early in-depth evaluation and monitoring during hospital stay. Prompt dysphagia and dysphonia evaluation and management is needed to minimise clinical and quality of life complications.