Awake endoscopic retrograde cholangiopancreatography in an ASA 4 patient using glossopharyngeal block

Abstract

Awake endoscopic retrograde cholangiopancreatography (ERCP) is infrequently performed, especially in patients with significant comorbidities. This case report documents the successful use of glossopharyngeal nerve block (GPNB) as the primary anaesthetic for an American Society of Anaesthesiologists (ASA) physical status class 4 male, 71 years old, with significant cardiac, pulmonary, and hepatobiliary comorbidities, who underwent awake ERCP with minimal intravenous sedation. The glossopharyngeal block effectively reduced the gag reflex and provided sufficient anaesthetic, allowing for the successful completion of ERCP without difficulties. The higher risk associated with general anaesthesia or deep sedation in this high-risk patient necessitated this approach.

Introduction

Endoscopic retrograde cholangiopancreatography (ERCP) is a diagnostic and therapeutic procedure commonly used for the management of biliary and pancreatic disease. Its use in high-risk patients represents a significant challenge due to increased vulnerability to potential complications of anaesthesia in addition to their severe systemic comorbidities. Established methods used in such cases are associated with haemodynamic instability and respiratory compromise.¹

This is the first report of a successful GPNB in a critically ill patient undergoing ERCP in Palestine, highlighting its safety and potential as a basis for future research to validate its safety, efficacy, and clinical applicability.

Case presentation

Our institution has exempted this study from ethical review.

A 71-year-old male with a history of lung fibrosis post-COVID-19, hypertension, and cardiac catheterisation, presented in December 2024 with worsening right upper quadrant pain, jaundice, and vomiting. Symptoms had been intermittent for four months, triggered by fatty meals, and were initially attributed to gallstones. On the day before admission, pain became persistent, accompanied by seven episodes of large volume vomiting.

On examination, he appeared ill, with right upper quadrant tenderness and respiratory findings consistent with pneumonia. Laboratory tests revealed abnormal liver function tests and assays of pancreatic enzymes, and elevated inflammatory markers, indicating acute cholangitis, probably due to choledocholithiasis. Abdominal ultrasound showed a contracted gallbladder with stones, fatty liver, and large bilateral renal cysts. ECG findings showed bi-fascicular block and atrial fibrillation.

Given the diagnosis of obstructive jaundice with acute cholangitis, the patient underwent urgent ERCP under regional anaesthesia, successfully relieving the obstruction.

Procedure

Given the patient's high-risk status, regional anaesthesia with a glossopharyngeal nerve block was chosen to suppress the gag reflex and facilitate awake ERCP while minimising systemic sedative requirements. He was placed in a 45-degree supine position with a nasal cannula delivering 4 l min⁻¹ of oxygen. Lidocaine spray (10%) was applied to the anterior tongue, the floor and roof of the mouth, and the tonsillar pillars. The area was left for 5 min to allow the drug to take effect and minimise discomfort.

A 22-gauge spinal needle was used to inject 4 ml of 2% lidocaine into each tonsillar pillar submucosally after the tongue was shifted medially using a tongue blade (Figure 1). This was done to block the glossopharyngeal nerve. The patient was then observed for 10 min to allow the anaesthetic to take full effect. One minute before the start of the procedure, the anaesthesiologist administered 1 mg i.v. midazolam and 20 mg i.v. ketamine to achieve mild hypnosis.

Fig. 1.

Glossopharyngeal nerve block.

Anterior tonsillar pillar method (taken from Narouze SN. Glossopharyngeal nerve block. In: Narouze NS, editors. Interventional management of head and face pain. New York, NY: Springer; 2014).

A balloon sweep was used to extract the stone, and a single pigtail stent was placed for drainage. The patient experienced discomfort during cannulation, and to alleviate this, 5 ml of 2% lidocaine was injected into the ampulla and biliary tree. The patient remained stable throughout the 65 min procedure, regaining full consciousness within 10 min of completion.

Discussion

Endoscopic procedures depend on effective anaesthesia to optimise patient comfort, safety, and procedural efficiency.¹ For this procedure, following an anaesthesiologist's assessment, the patient is positioned in a traditional ERCP posture, prone or semi-prone. This, combined with the partial airway obstruction induced by the large endoscope, usually leads to mild hypoxia.^2,3 However, given the patient's advanced age, low baseline SpO2, and current pneumonia, it was thought that general anaesthesia posed significant risks, such as acute respiratory distress syndrome, postprocedure ICU stay, increased expenditures, and potential sequelae.^1,3 As a consequence this ASA 4 patient had regional anaesthesia by GPNB to inhibit the gag reflex, minimise sedative needs, and preserve cardiopulmonary stability. Submucosal lidocaine successfully suppressed the gag reflex, allowing for easy endoscope insertion. Mild sedation with midazolam and ketamine relieved patient anxiety at the start of the procedure, as has been documented before, without affecting haemodynamic stability.⁴ GPNB suppresses the gag reflex by anaesthetising pressure-sensitive receptors, rather than just tactile receptors in the posterior tongue and oropharynx.⁵

The use of GPNB contributed directly to the overall success of the procedure while preserving the patient's respiratory drive. We observed no procedural interruptions, and the patient remained co-operative throughout. Notably, the technique minimised risks of sedation and demonstrated cost-effectiveness when compared to general anaesthesia. This approach improves procedural safety, enhances patient outcomes, and shortens recovery times and postprocedure monitoring, addressing significant challenges in managing high-risk patients.^4,6,7

There were some procedural complications of GPNB to consider,⁴ such as intravascular injection and systemic toxicity, inadvertent carotid sinus afferent nerve fibre blockade, unilateral headache, seizures, and arrhythmias, especially supraventricular tachycardia. Careful aspiration and slow anaesthetic injection minimised these risks.⁴ Postprocedure monitoring confirmed stable vital signs and showed no adverse events, further validating the safety and efficacy of this approach.

Despite the encouraging outcomes reported both in this case and in previous literature, several limitations must be considered. This report describes the experience of a single patient, which limits the generalisability of the findings.^4,6,7 Also GPNB requires advanced technical skills, extended preparation time, and precise anatomical knowledge, all of which may hinder its broader adoption.^4,5

Conclusion

Glossopharyngeal nerve block with minimal sedation in high risk patients undergoing advanced endoscopic procedures such as ERCP could be an alternative for standard anaesthetic methods.