What is the best treatment approach for a patient with hiccups due to a fracture with phrenic nerve injury?

Treatment of Hiccups After Fracture with Phrenic Nerve Injury

For hiccups due to phrenic nerve injury from fracture, initiate chlorpromazine 25-50 mg IM/IV as first-line pharmacotherapy while providing respiratory support with non-invasive ventilation if needed, and consider phrenic nerve block if pharmacotherapy fails within 2-3 days. 1

Immediate Assessment and Stabilization

Respiratory Function Evaluation

• Assess for hemidiaphragmatic paralysis by checking for elevated hemidiaphragm on chest X-ray, paradoxical abdominal motion during inspiration, and increased work of breathing 2
• Perform bedside diaphragmatic ultrasound to objectively assess diaphragmatic function, particularly if the patient shows signs of respiratory distress or difficulty with ventilation 2, 3
• Monitor for hypercapnia with transcutaneous CO2 monitoring or arterial blood gases, as diaphragmatic dysfunction can lead to CO2 retention 3
• Initiate non-invasive ventilation promptly if the patient demonstrates respiratory distress, hypercapnia, or oxygen saturation below target (88-92% in adults) 2, 3

Diagnostic Confirmation

• Consider phrenic nerve stimulation techniques (electrical or magnetic) to provide objective assessment of diaphragm function independent of patient effort 4, 2, 5
• Measurement of twitch transdiaphragmatic pressure (Pdi,tw) following phrenic nerve stimulation can specifically quantify diaphragm strength, with values below normal ranges indicating significant dysfunction 4, 2

Pharmacological Treatment Algorithm

First-Line: Chlorpromazine

Chlorpromazine is the FDA-approved first-line treatment for intractable hiccups. 1, 6, 1

Dosing regimen:

• Oral route (if patient can tolerate): 25-50 mg three to four times daily 6
• If symptoms persist for 2-3 days after oral therapy: Give 25-50 mg IM 1
• If symptoms still persist: Use slow IV infusion with patient flat in bed: 25-50 mg in 500-1000 mL of saline, following blood pressure closely 1
• Critical safety measure: Avoid injecting undiluted chlorpromazine into vein; IV route is only for severe hiccups, surgery, and tetanus 1
• Keep patient lying down for at least 30 minutes after injection due to hypotensive effects 1

Alternative Pharmacological Options

If chlorpromazine is contraindicated or ineffective, consider 7:

• Gabapentin for neuropathic modulation of the hiccup reflex arc
• Baclofen as a GABA-B agonist to suppress the reflex
• Metoclopramide as a prokinetic agent, particularly if gastroesophageal factors contribute

Interventional Treatment Options

Phrenic Nerve Block

If pharmacotherapy fails after 2-3 days, phrenic nerve block is the next definitive intervention. 8, 9, 10

Technical approach:

• Ultrasound-guided phrenic nerve block is the preferred method, offering precise localization and safety 9
• Use local anesthetic (bupivacaine) with or without corticosteroid (depomedrol) 9
• Bilateral sequential blocks may be necessary: perform unilateral block first, assess response over 3 days, then consider contralateral block if needed 9
• This provides long-term therapeutic benefit with complete resolution of hiccups in selected cases 9

Alternative nerve block techniques:

• Cervical phrenic nerve block under electromyography guidance for precise localization 8
• Thoracoscopic reversible phrenic nerve clipping under general anesthesia, with the advantage of assured diaphragmatic functional recovery while controlling hiccups 10

Mechanical Ventilation for Refractory Cases

For truly intractable hiccups unresponsive to all other measures: Short-term positive pressure ventilation using a short-acting muscle relaxant can successfully interrupt the hiccup reflex arc 11

Respiratory Management During Treatment

Ventilatory Support Strategy

• Use controlled ventilation modes as patient triggering may be ineffective with phrenic nerve dysfunction 2, 3
• Avoid excessive oxygen administration in isolation, as it can worsen hypercapnia; target oxygen saturation of 88-92% in adults 3
• Before initiating weaning from mechanical ventilation: ensure the precipitant cause is treated, pH is normalized, and chronic hypercapnia is corrected 3
• Implement physiotherapy treatment before and after extubation to reduce weaning duration 2, 3

Extubation Planning

• Plan extubation carefully in a specialized setting with non-invasive ventilation support available 2, 3
• Consider prophylactic non-invasive ventilation after extubation for patients at high risk of reintubation 2, 3

Long-Term Management Considerations

Conservative Management

• Most phrenic nerve injuries will recover within 3-6 months if the nerve is not transected 2
• Continue respiratory support with nocturnal non-invasive ventilation if needed for sleep-disordered breathing 2, 3
• Implement respiratory muscle training and physiotherapy 2

Advanced Options for Persistent Dysfunction

Diaphragm pacing may be considered for long-term management in carefully selected patients with 2, 5:

• No or mild intrinsic lung disease
• Non-obese status
• Intact phrenic nerve-diaphragm axis (confirmed by phrenic nerve stimulation studies)

Critical Pitfalls to Avoid

• Do not delay respiratory support: Phrenic nerve injury can cause significant respiratory compromise requiring immediate non-invasive ventilation 2, 3
• Do not administer undiluted chlorpromazine IV: This can cause severe hypotension and vascular injury 1
• Do not perform bilateral phrenic nerve blocks simultaneously: This can cause complete diaphragmatic paralysis; always perform sequentially 9
• Do not overlook the underlying fracture management: Appropriate fracture treatment is essential for overall recovery 4