Criteria lor determining the severity of respiratory failure of patients suffering bilateral vocal fold paralysis
Authors: Shidlovskaya Tetiana , Pavlyk Boris , Zemlyak T. 
Published: May 2020

Topicality: Despite of the large number of research works concerning respiratory failure of patients suffering bilateral vocal fold paralysis, there are no objective systematized data of clinical and instrumental studies characterizing this verity of ventilation obstructive insufficiency of external respiration and their interpretation, taking into account the aerodynamic condition pathophysiology in vocal fold mobility presence or absence.
Purpose: Definition of the criteria for the severity of respiratory failure of patients suffering bilateral vocal fold paralysis, based on a study of external respiration state according to the spirometry.
Materials and methods: 106 patients suffering bilateral vocal fold paralysis took part in thes study. They were divided into two groups. 55 patients suffering bilateral vocal fold paralysis entered the first group while 51 patients suffering bilateral vocal fold paralysis who received surgery treatment, namely endoscopic unilateral chordoarytenoidotomy. As a control group, 15 practically healthy people, having not any disturbances of vocal apparatus or respiratory system, were examined. All the patients underwent a standard respiratory quality survey (SGRQ survey), laryngeal endoscopy (Storz, Germany), spirometric studies of external respiratory function (Vitalograph Pneumotrac, Germany).
Results: In order to search for criteria that would allow a more accurate assessment of the patient's external respiration, as well as maximally approximate objective and subjective assessment, we made subdivision of the first group patients, suffering bilateral vocal fold paralyses, into two subgroups: subgroup 1a and subgroup 1b. Subgroup 1a included the patients suffering bilateral vocal fold paralysis whose value indicator of the subjective overall assessment according to SGRQ data was up to 70 points (n=29). While subgroup 1b included the patients whose indicator was more than 70 points (n=26). According to spirometry data, all the patients showed signs of obstructive ventilation of respiratory failure expressed in varying degrees, namely, a significant decrease in speed indicators FEV1, PEF and PIF compared with the control group (p<0,01). The most significant was a decrease in peak inspiration volume tricrate PIF, the value of which in patients suffering bilateral vocal cords fold paralysis was less than 50% of the standard nominative values. The lowest values of PIF indicator (22,14±1,41%) were determined in subgroup 1b. 61,54% of patients’ this subgroup, who clinically had the most pronounced indicators of respiratory failure, also revealed a decrease in peak expiration volume tricrate PEF (31,36±2,31%) less than 40%. PEF and PIF indicators of patients in subgroup 1b had a significant difference from PEF and PIF indicators in subgroup 1a (PEF – 45,92±4,40%,
PIF – 34,08±1,60%) and group 2 (PEF – 53,22±2,48%, PIF – 37,78±2,35%) (p<0,01). Besides, the patients in subgroup 1b showed a significant decrease in VC and FVC indicators as compared to group 2 and subgroup 1a (p<0,01, p>0,05).
Conclusions: Speaking about patients suffering bilateral vocal cords fold paralysis, their most informative criterion for determining these verity of the obstructive variant of ventilation respiratory failure, as well as of the effectiveness of the treatment used, is PEF indicator and, especially, PIF indicator. Indicators of PIF (22,14±1,41%) and PEF (31,36±2,31%), differing for more than 80% and 60 % from normative indicators, are considered to be critical. They prove of severe respiratory failure.