Back to the drawing board-relearn the clinical skills: A root cause analysis of a missed case of bilateral vocal cord paralysis.

Bilateral vocal cord paralysis being misdiagnosed as bronchial asthma has been reported in the literature on several occasions. Diagnosing this condition needs precise clinical acumen which could lead us to make an integrated diagnostic and treatment plan. Here, we report another missed case of bilateral vocal cord paralysis and the root cause analysis of the incident. This report emphasises the need for appropriate clinical examinations and workup during the pre-operative assessment.

INTRODUCTION

Vocal cord paralysis is a feature of numerous diseases with either neurogenic or mechanical causes. Hence, clinical diagnosis of the underlying pathology leading to paralysis of the vocal cords is necessary for further management.[1] Bilateral vocal cord paralysis which was misdiagnosed as bronchial asthma on several circumstances had been reported in the literature.[23] Here, we report another missed case of bilateral vocal cord paralysis and its root cause analysis (RCA).

CASE REPORT

A 55-year-old male presented to our hospital with complaints of abdominal pain associated with intermittent episodes of vomiting for 1 year. On evaluation, he was diagnosed to have carcinoma stomach. Apart from this, he was a known case of bronchial asthma for 25 years, not on regular treatment. The recent exacerbation was 2 months earlier which was treated by salbutamol metered dose inhaler (MDI). On admission to our hospital, he was started on salbutamol nebulisation by the surgical team. After pulmonology opinion, he was started with Seroflo™ (salmeterol and fluticasone) MDI.

He was planned for laparotomy and proceed. During the pre-anaesthesia check-up (PAC), the patient was found to have bilateral rhonchi on auscultation for which pulmonology review was requested for further optimisation. Ipratropium nebulisation and low-dose oral prednisolone were added. The surgery was postponed in view of persistent bilateral rhonchi. Later, he was posted for surgery after 2 weeks. During the review PAC, the patient still had rhonchi, but the intensity had apparently reduced. Hence, the patient was accepted for anaesthesia and surgery with appropriate informed risk in view of malignancy. General anaesthesia with endotracheal intubation after appropriate blunting of the laryngoscopic response was planned. In the operating theatre, standard monitors were established. Anaesthesia was induced with fentanyl 100 μg, propofol 100 mg and muscle paralysis was achieved with 6 mg of vecuronium. Lungs were ventilated with sevoflurane in oxygen and lignocaine was administered to blunt the laryngoscopic response. Trachea was intubated with a 7.5 mm endotracheal tube in single attempt. On auscultation, there was no wheeze which was there before induction of anaesthesia. As the patient's wheezing disappeared after intubation, upper airway pathology was suspected. Airway pressure was 12 cm of H2O in volume control mode with tidal volume 450 ml, I: E = 1:2, respiratory rate of 12/min. Capnogram was normal and end-tidal carbon dioxide, and oxygen saturation was within normal limits. As the gastric growth was infiltrating the pancreas, only palliative gastrojejunostomy was done. At the end of surgery, the residual neuromuscular blockade was reversed, and the patient was extubated. The patient was having noisy breathing with bilateral wheezing on auscultation. Hence, fibreoptic bronchoscopy was performed. We had observed that both the vocal cords were in adducted position. After correlating the clinical findings, we assumed that the patient could have had bilateral vocal cord paralysis preoperatively itself. As the patient was maintaining oxygenation saturation, the patient was not intubated immediately. After discussing with the otolaryngologist, he was shifted to Intensive Care Unit (ICU) for observation.

Even though the patient was having noisy breathing, he was maintaining oxygenation at room air and was haemodynamically stable. He was explained about his condition, associated risks and the need for emergency tracheostomy. However, he was not willing as he had been living with the same condition for a long time without any discomfort. He was shifted out of ICU and discharged subsequently. During post-operative follow-up, at 2 months, the tele laryngoscopy again confirmed the bilateral vocal cord paralysis [Figure 1]. The flow volume loop [Figure 2] did not reveal any features of inspiratory obstruction. Even though the patient had obstruction during both phases of respiration [Video 1], he was comfortable without any obvious stridor. As he was having this condition for many years, he did not give consent for tracheostomy. He came for regular follow-ups and was found to be asymptomatic.

Figure 1

The position of bilateral vocal cord during inspiration (a) and expiration (b)

Figure 2

The flow volume loop which did not show any evidence of inspiratory obstruction

DISCUSSION

Recurrent laryngeal nerve function can be impaired due to pressure or pathology of the disease damaging the nerve leading to paralysis of the vocal cords. Even an uncomplicated endotracheal intubation could result in this complication. But in our case, the vocal cord paralysis could not be due to endotracheal intubation. We assumed the bilateral vocal cord paralysis could be pre-existing in our patient because the airway pressure and auscultatory findings were normal just after intubation. The diagnosis was also confirmed by the tele laryngoscopy during the post-operative follow-up. The patient still had the bilateral vocal cord paralysis and wheezing on auscultation during the post-operative follow-up.

The rhonchi could be either in inspiratory or expiratory phase, and the bronchial asthma always presents with expiratory wheezing. The clinical examination should be done carefully to differentiate the inspiratory and expiratory nature of wheezing. The presence of wheezing in either inspiratory or biphasic should have been evaluated for other causes which was missed in our case. The assessment of patients with vocal cord paralysis includes a full evaluation of the head, neck and larynx by chest X-ray, computed tomography scan or magnetic resonance imaging of the skull base to the thoracic inlet for eliminating the brain stem, neck, chest and mediastinum causes.

Even after the medications, the persisting wheezing of bronchial asthma needs further evaluation to rule out any upper airway obstruction which was missed in our case. Hence, we performed the root cause analysis with 5-why analysis [Table 1]. This case of bilateral abductor cord palsy was ignored as we were preoccupied with the diagnosis of existing chronic asthma. It was overlooked as the clinical examination was not performed properly to appreciate the biphasic nature of wheezing.

Table 1

Root cause analysis

The diagnostic modalities for any pulmonary disease range from the simple bedside pulmonary function tests to several advanced investigations. The bedside pulmonary assessment helps to diagnose many conditions and also aids in choosing the advanced evaluation options. However, the art of bedside pulmonary assessment is vanishing nowadays. The fading clinical expertise in cardiac and pulmonary assessment has been acknowledged in the literature. Several techniques including simulation also have been used to improve the pulmonary auscultation skills.[456] We should bank on simulators only for unusual pulmonary conditions. The common conditions can be diagnosed certainly if the necessary clinical skills are performed decorously. The clinical skill lone would help us in the management of patients with an emergency condition. This case was discussed in our departmental review meeting, among all anaesthesiologists and the significance of this basic auscultatory skill was emphasised.

CONCLUSION

We report this case to highlight the significance of proper clinical examinations and workup during pre-operative assessment for patient safety. We suggest that all anaesthesiologists should be acquainted with the advanced diagnostic modalities. We also suggest everyone to revamp their basic auscultatory skill for better patient management.

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Conflicts of interest

There are no conflicts of interest.