The flow-volume loop in bilateral vocal cord paralysis

Use of flow volume curve to evaluate large airway obstruction

The flow volume loop (FVL) is a graphic display of airflow against lung volumes at different levels obtained during the maximum inspiratory and expiratory maneuver. It is a simple and reproducible method of lung function assessment. A narrative review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. PubMed, EMBASE, Ovid MEDLINE and CINAHL databases were queried and reviewed for studies pertinent to the various FVLs abnormalities and their mechanisms from January 2020 to December 2020. We used the following search terms; flow-volume loop, upper airway obstruction, Obstructive airway disease, and spirometry.  Assessing the shape of the flow-volume loop is particularly helpful in diagnosing and localizing upper airway obstruction. They are also helpful in identifying bronchodilator response to treatment. Characteristic FVLs is also seen in patients with obstructive or restrictive lung disorders. Spirometry should be interpreted using the absolute values for flows and volumes as well as the flow volume and volume time curves.

Asthma mimic: Case report and literature review of vocal cord nodule associated with wheezing

Asthma is a heterogeneous disease, usually characterized by chronic airway inflammation. Various clinical conditions can mimic asthma, such as foreign body aspiration, subglottic stenosis, congestive heart failure, diffuse panbronchiolitis, aortic arch anomalies, reactive airway dysfunction syndrome, chronic obstructive pulmonary disease, retrosternal goiter, vocal cord tumors, other airway tumors, and vocal cord dysfunction. Upper airway obstruction can be a life-threatening emergency. Here, we present the case of a 58-year-old female with recurrent hospital visits for wheezing and exacerbations of asthma, who was later found to have a vocal cord nodule confirmed to be squamous cell carcinoma, which was mimicking like asthma.

Repeated episodes of respiratory failure due to bilateral vocal cord paralysis

BACKGROUND

Bilateral vocal cord paralysis can produce severe airway obstruction, leading to acute respiratory failure. Discriminating the pathology of the upper airway from chronic obstructive diseases of the lower airways often presents a challenge for clinicians in the Emergency Department.

OBJECTIVES

To underlie the value of clinical examination and flow-volume loops in the establishment of diagnosis of upper airway obstruction.

CASE REPORT

We describe the case of a 55-year-old female ex-smoker who presented with a long history of hoarseness and progressive exertional dyspnea. The patient developed repeated episodes of acute respiratory failure and was supported with noninvasive ventilation. The diagnosis of bilateral vocal cord paralysis was finally established by patient's symptoms and flow-volume loops demonstrating variable extrathoracic obstruction.

CONCLUSION

Vocal cord paralysis is a rare and often neglected condition, contributing to repeated episodes of acute respiratory failure. Flow-volume loop is a useful tool when symptoms are suggestive of upper airway obstruction.

Quantifying the Physiology of Laryngotracheal Stenosis: Changes in Pulmonary Dynamics in Response to Graded Extrathoracic Resistive Loading

OBJECTIVES/HYPOTHESIS

A model of airway obstruction was developed to study the impact of changes in airway resistance on ventilatory mechanics. This was used to derive quantitative indices of airway obstruction to aid in the objective diagnosis and physiological monitoring of adult patients with laryngotracheal stenosis (LTS).

METHODS

Six airway resistors, the characteristics of which mirrored the selective impediment to inspiratory airflow that occurs in patients with LTS, were created and calibrated. Maximum-effort flow-volume loops were obtained from 15 volunteers with resistors placed in series with the spirometer. Diagnostic and monitoring performances of various flow-volume indices were assessed with receiver-operating characteristics (ROC) and analysis of variance (ANOVA), respectively. Promising indices were further evaluated in patients with LTS.

RESULTS

Experimentally, the ratio of expiratory and inspiratory flows at midvital capacity (MEF50/MIF50) and peak expiratory to inspiratory flow ratio (PEF/PIF) had diagnostic sensitivities of 87% and 89%, respectively. The best index, both experimentally and clinically, was the ratio of area under the expiratory and inspiratory curves (ratio of integrals), with experimental and clinical sensitivities of 97% and 100%, respectively. A clinical specificity of 95%, and area under the curve of 0.965 were achieved for this index. Both PEF/PIF and the ratio of integrals could identify step changes in airway resistance greater than 10 cmH2O . sec . L (P < .05; ANOVA).

CONCLUSIONS

Flow-volume testing is simple and noninvasive and can be used to quantify the diagnosis and physiological monitoring of patients with LTS. The ratio of areas under the expiratory and inspiratory curves appears to be the optimal index for this purpose.

The influence of laser arytenoidectomy on ventilation parameters in patients with bilateral vocal cord paralysis

Bilateral vocal cord paralysis is a symptom that may lead to serious breathing problems. The treatment of patients with vocal cord paralysis presents a challenge to otolaryngologists. Many techniques have been developed in an attempt to improve the patient's airway insufficiency. The aim of the study was to evaluate the efficacy of the laser total unilateral arytenoidectomy with posterior cordectomy in patients with bilateral vocal cord paralysis. Thrity-six patients (33 females, 3 male) aged between 24 and 76 (mean 52) were treated by laser arytenoidectomy. The flow-volume loop and pletysmography were performed in all patients before and after the operation. Additionally, a group of 15 patients with unilateral vocal cord paralysis was introduced and analyzed as a special control. Based on the relative increase of the parameters after the surgery, the most useful of them were selected for the evaluation. Also, the character of the laryngeal obstruction was defined. Changes in the flow-volume loop before and after surgery were compared by planned comparison in univariate analysis ANOVA/MANOVA with an isolated control group. As the parameters AREA(EX), FEF50, FEF75, PEF and MMEF(75/25) increased most effectively, they appeared to be the most useful in the evaluation. FIV1/FEF1, FEF50/FIF50 and FEV1/FEV(0,5) allowed the definition of the obstruction as an extrathoracic dynamically variable quantity. The resistances measured during pletysmography diminished significantly after surgery. The introduction of the special control group with unilateral vocal cord paralysis showed that despite the significant improvement after surgery, the patients who had been operated on still had a laryngeal obstruction worse than that of patients from the control group. The laser arytenoidectomy is shown to be a useful and efficacious procedure for bilateral vocal cord paralysis.