Heparin Nebulisation in Airway Edema in Burns
Nebulized heparin is NOT recommended for managing airway edema in burn patients based on the most recent high-quality evidence showing significant safety concerns, including serious respiratory problems from expiratory filter saturation and frequent treatment interruptions due to bleeding risks. 1
Critical Safety Concerns from Highest Quality Evidence
The 2020 multicenter, double-blind, placebo-controlled randomized trial was prematurely stopped after enrolling only 13 patients due to serious safety and feasibility issues 1:
- Serious respiratory problems occurred in the heparin group due to saturation of expiratory filters following nebulizations 1
- 129 out of 427 scheduled nebulizations (30%) were withheld in the heparin group across 3 patients 1
- Blood-stained sputum and increased bleeding risks were the most frequent reasons for withholding treatment 1
- The trial investigators concluded that important safety and feasibility issues should be considered before using heparin nebulizations in burn patients with inhalation trauma 1
Mechanism and Theoretical Rationale
Smoke inhalation causes airway injury through thermal and chemical irritation, leading to airway edema, capillary leak, and formation of fibrin casts with mucin debris 2, 3. Nebulized heparin theoretically works by:
- Dissolving fibrin clots in the airways 3
- Reducing pulmonary hypercoagulopathy intrinsic to inhalation trauma 1
- Decreasing inflammatory response 4
Conflicting Lower-Quality Evidence
While the most recent randomized controlled trial showed safety concerns 1, several older retrospective case reports and case-control studies suggested potential benefits:
- A 2017 case-control study (n=72) reported decreased mechanical ventilation duration [7.0 vs 14.5 days, P=.044] and increased ventilator-free days [21.0 vs 13.5 days, P=.031] with nebulized heparin 10,000 units every 4 hours 4
- Case reports from 2018 and 2022 described successful outcomes with combination nebulized heparin and N-acetylcysteine 2, 3
- A 2011 retrospective study (n=63) found no clinically significant increase in bleeding risk 5
However, these studies are methodologically inferior to the 2020 randomized controlled trial and do not address the serious respiratory complications from filter saturation. 1
Guideline-Based Management of Airway Edema in Burns
Current guidelines do NOT recommend nebulized heparin for airway edema management. Instead, focus on:
Selective Intubation Criteria
Patients with burns involving the face or neck should NOT be routinely intubated 6, 7. Intubate only when specific high-risk features are present 6, 7:
- Deep and circular burn on the neck 6, 7
- Symptoms of airway obstruction (voice modification, stridor, laryngeal dyspnea) 6, 7
- Very extensive burns (TBSA ≥40%) 6, 7
- Severe respiratory distress, severe hypoxia/hypercapnia, or coma 6, 7
Monitoring and Conservative Management
For patients without immediate intubation indications 7:
- Observe in high-dependency area with head-up positioning 7
- Keep nil-by-mouth 7
- Perform regular reassessment to detect deterioration early 7
- Obtain specialist advice early from a burns center 7
Common Pitfalls to Avoid
- Nearly one-third of burn patients are unnecessarily intubated in the prehospital setting, leading to more complications and longer hospital stays 7
- Do not perform bronchial fibroscopy outside burn centers to avoid transfer delays 6, 7
- Anticipate difficult intubation and use modified rapid sequence induction with video laryngoscopy if available 7
- Avoid succinylcholine from 24 hours post-injury onward due to hyperkalemia risk 7
Clinical Bottom Line
Given the serious safety concerns from the most recent and highest quality randomized controlled trial, nebulized heparin should not be used for managing airway edema in burn patients. 1 Focus instead on guideline-based selective intubation criteria, close monitoring, and early transfer to specialized burn centers for patients with face/neck burns and suspected smoke inhalation. 6, 7