Effects of Distance, Noise, and Personal Respiratory Protective Equipment on Speech Comprehension in Simulated Critical Care Setting

<b>Background/Objectives:</b> Effective communication in critical care is crucial, particularly with the constraints of Personal Protective Equipment (PPE). This study aimed to evaluate speech intelligibility under varying conditions of distance, ambient noise, and PPE types in a simulated ICU. <b>Methodology:</b> A quasi-experimental design was used with 23 participants in 24 scenarios, combining three distances (1, 2, and 5 m), two noise levels (quiet and ICU-like), and four PPE types (no mask, surgical mask, N95, and PAPR). Speech intelligibility was assessed by positioning the subjects at varying distances while playing phonetically balanced words through a playback device equipped with the different PPE being tested. The evaluation was conducted under two sound conditions (25 dB(A) and 45 dB(A)). The percentage of correct responses by the subjects to the perceived sounds was determined as a measure of intelligibility. The relation between variables was analyzed using the Wilcoxon Test and the Friedman Test. <b>Results:</b> Significant differences in word recognition were observed across conditions. Ambient noise reduced intelligibility, with recognition percentages significantly lowering in noisy environments. PPE type also influenced comprehension, with PAPR posing the greatest challenge. Friedman's test showed that increasing distance significantly decreased recognition accuracy. Distances beyond two meters negatively impacted intelligibility across all devices tested. <b>Conclusions:</b> In noisy conditions (>45 dB(A)), a combination of distances greater than two meters and PPE use reduced intelligibility by over 40%, potentially compromising patient safety. The use of communication aids, such as visual cues or alternative speech devices, is recommended, particularly with PAPRs, to enhance comprehension and ensure effective communication between healthcare providers and patients.