Correlation between voluntary cough and laryngeal cough reflex flows in patients with traumatic brain injury

Abstract

OBJECTIVE: To correlate voluntary cough and laryngeal cough reflex (LCR) flows in patients with traumatic brain injury (TBI).

DESIGN: Cross-sectional study.

SETTING: University rehabilitation hospital.

PARTICIPANTS: Patients with TBI (n=25) and healthy controls (n=48).

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: Peak cough flows (PCFs) and LCR flows were measured using a peak flow meter at the oral-nasal interface. The largest value of 3 attempts was recorded for PCF and LCR, respectively. LCR was elicited by 20% solution of pharmaceutic-grade citric acid dissolved in sterile .15M NaCl solution that was inhaled from a nebulizer.

RESULTS: PCF was 447.4 ± 99.0 L/min in the control group and 211.7 ± 58.2 L/min in the patient group. LCR was 209.2 ± 63.8L/min in the control group and 170.0 ± 59.7 L/min in the patient group. Both PCF (P=.000) and LCR (P=.013) were significantly reduced in patients with TBI compared to that of the control group. LCR was strongly related to the PCF in both control (R=.645; P=.000) and patient (R=.711; P=.000) groups.

CONCLUSIONS: As LCR can be measured as a numerical value and significantly correlates with PCF, LCR can be used to estimate cough ability of patients with TBI who cannot cooperate with PCF measurement.