Hearing Deficits Assessment by Pure Tone Audiometry Amongst the Survivors of Intensive Care Unit: A Prospective Observational Cohort Study

OBJECTIVES: Hearing abnormality is an under-recognised phenomenon in critically ill patients. To assess hearing deficits (HD) through pure tone audiometry (PTA), amongst the survivors of intensive care unit (ICU). MATERIALS AND METHODS: In this prospective observational study, ICU survivors aged more than 18 years, who were conscious, oriented, and able to communicate for audiometric tests at the time of discharge were screened to be included in the study. Those patients with previous history of hearing loss or any ear pathology and patients with head trauma or diagnosed central nervous system (CNS) pathologies in the discharge summary like cerebrovascular disease (stroke), acute or chronic meningoencephalitis, and any other pathology known to affect hearing pathways were excluded from the study. Any survivor, who was unable to cooperate and consent for audiometric screening at the time of ICU discharge was also excluded. The recruited survivors were subjected to PTA and were classified into two groups based on PTA findings as those “with HD” and “without HD”. Baseline clinical data of the patients at the ICU admission along with the duration of organs supports received along with the length of stay in ICU (LOS ICU) was noted from bedside case files. A sample size of 100 was calculated assuming 50% prevalence of hearing abnormality among ICU patients with 95% confidence level, 80% power, and 20% relative precision. Multivariable logistic regression analysis was done to identify the predictors of the hearing deficits. Propensity score matching (PSM) was performed using APACHE-II score as a covariate and estimating the effect size. A p value ≤0.05 was considered statistically significant. RESULTS: One hundred and two survivors were enrolled with a median age of 25.5 years (23-30.5), and acute physiology and chronic health evaluation (APACHE II) score of 19 (14-22). Sixty were diagnosed (58.89%) with HD based on PTA, and forty-two (41.2%) without HD. More than 80% of the survivors (52/60) had sensorineural hearing loss (SNHL). PSM, after the exact matching of the APACHE-II score between those “with HD” and “without HD”, revealed that patients with HD had a longer duration of shock (mean ± SD) (0.96 ± 1.24 vs 1.68±1.28; p value: 0.022), received higher maximum noradrenaline dose (0.03 v/s 0.06 μg/kg/min; p value: 0.004), longer duration of endotracheal tube (2.04 ± 1.17 vs 3.52 ±2.06) days; p value: 0.009), more days on mechanical ventilation (2.24 ± 1.33 vs 4.44 ± 5.12; p value: 0.011), and length of stay in the ICU (7.2 ± 3.8 vs 9.24 ± 4.68; p value: 0.013) than those without HD. CONCLUSIONS: There exists high prevalence of up to 59% of hearing deficits in survivors of critical illness, with the most common up to 87% being sensorineural hearing loss (SNHL). Apart from the severity of illness at admission, duration of endotracheal tube, duration of mechanical ventilation, shock days and maximum dose of norepinephrine received, and LOS ICU were the risk factors. TRIAL REGISTRATION: Clinical trials registry. India (CTRI/2022/01/039539) dated 18.01.2022. https://ctri.nic.in/Clinicaltrials/login.php.