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outside of the intensive care setting. Twelve (93 %) discontinued LMWH on discharge, and one unit continued LMWH after discharge in patients with lower limb burns and reduced mobility.

We can conclude from this survey that UK burn centres are increasingly utilising AFXa measurement to guide LMWH dosing. Since 2019, the number of centres and units monitoring AFXa levels has increased by 150 %. This may be secondary to increased awareness and literature on the topic, as well as the increased popularity of AFXa monitoring in COVID-19 patients during the pandemic. There is currently no published data to report whether AFXa monitoring leads to a reduction in VTE incidence and improved patient outcomes in burns patients. More research in this in this area is needed.

#### **Funding**

None.

### **Ethics approval**

Not required.

### **Declaration of Competing Interest**

None.

REFERENCES

[1] Pannucci C, Osborne N, Wahl W. Venous thromboembolism in thermally injured patients: analysis of the national burn repository. J Burn Care Res 2012;32:6–12. https://doi.org/ [https://doi.org/10.1097/BCR.0b013e318204b2ff.](https://doi.org/10.1097/BCR.0b013e318204b2ff) PMID: 21127423; PMCID: PMC3040596.

- [2] Sharma SK. Low molecular weight heparins. Med J Armed Forces India 1998;54(3):285–6. https://doi.org[/https://doi.](https://doi.org/10.1016/S0377-1237(17)30571-3) [org/10.1016/S0377](https://doi.org/10.1016/S0377-1237(17)30571-3)-1237(17)30571-3. Epub 2017 Jun 26. PMID: 28775503; PMCID: PMC5531654.
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- [4] Cato LD, Bailiff B, Price J, Ermogeneous C, Hazeldine J, Lester W, et al. Heparin resistance in severe thermal injury: a prospective cohort study. Burns Trauma 2021;9:tkab032. https://doi.org[/https://doi.org/10.1093/burnst/tkab032](https://doi.org/10.1093/burnst/tkab032). PMID: 34692855; PMCID: PMC8528639.
- [5] Vermaak PV, D'Asta F, Provins J, Farr M, Wilson YT. Thromboprophylaxis in adult and paediatric burn patients: a survey of practice in the United Kingdom. Burns 2019;45 (6):1379–85. https://doi.org/[https://doi.org/10.1016/j.](https://doi.org/10.1016/j.burns.2019.04.003) [burns.2019.04.003](https://doi.org/10.1016/j.burns.2019.04.003). Epub 2019 May 10. PMID: 31079961.
- [6] Dutt T, Simcox D, Downey C, McLenaghan D, King C, Gautam M, et al. Thromboprophylaxis in COVID-19: Anti-FXa – the missing factor? Am J Respir Crit Care Med 2020;202(3):455–7. https://doi.org[/https://doi.org/10.1164/](https://doi.org/10.1164/rccm.202005-1654LE) [rccm.202005](https://doi.org/10.1164/rccm.202005-1654LE)-1654LE. PMID: 32510975; PMCID: PMC7397804.

Anna Payne ⁎ , Phillippa Richardson, Preetha Muthayya *Department of Burns and Plastic Surgery, Pinderfields Hospital, Mid Yorkshire Hospitals NHS Trust, Aberford Road, Wakefield WF1 4DG, United Kingdom E-mail address:* [anna.payne@doctors.org.uk](mailto:anna.payne@doctors.org.uk) (A. Payne)

Accepted 26 September 2022

<https://doi.org/10.1016/j.burns.2022.09.011> 0305-4179/ © 2022 Elsevier Ltd and ISBI. All rights reserved.

⁎ Corresponding author.

# **Extracorporeal membrane oxygenation utilization in burn patients with severe acute respiratory distress syndrome**

*Dear Editor,*

Extracorporeal membrane oxygenation (ECMO) shows great promise as a rescue therapy for burn patients with inhalation injury or other forms of acute respiratory distress syndrome (ARDS). While the mainstay of traditional ARDS management in the non-burn patient includes lung protective ventilation, conservative fluid management, prone positioning and neuromuscular blockade [[1](#page-3-0)], these strategies may not be feasible in the burn patient who requires ongoing fluid resuscitation and frequent operative procedures [[2,3](#page-3-0)]. ECMO support may be especially useful in mitigating these limitations and rescuing burn patients in whom ARDS progresses despite maximal traditional management. ECMO has been successfully used in patients with very large burns [[4](#page-3-0)], with reported mean survival rates of 43–47% [[5](#page-3-0)].

To better describe the use of ECMO in an American Burn Association-verified center, we reviewed all adult patients with a diagnosis of burn injury admitted to our

![](https://assets.reachrx.ai/images/10.1016%E2%98%8Dj.burns.2022.10.003/_page_1_Picture_25.jpeg)

| Table 1 – Patient & burn characteristics. | | | | | | | | | | |
|----------------------------------------------------------------------------------|------------|-----------------|---------------------|--------------|-----------|------------|--|--|--|--|
| Patient | Age (Year) | TBSA Injury (%) | Inhalational Injury | Revised Baux | APACHE II | PaO2 nadir | | | | |
| 1 | 45 | 50 | Yes | 112 | 25 | 46 | | | | |
| 2 | 47 | 35 | Yes | 99 | a | a | | | | |
| 3 | 20 | 45 | Yes | 82 | a | a | | | | |
| 4 | 34 | 40 | No | 74 | 21 | 40 | | | | |
| 5 | 69 | 10 | Yes | 96 | 24 | 72 | | | | |
| 6 | 21 | 20 | Yes | 58 | 35 | 61 | | | | |
| 7 | 56 | 16 | Yes | 89 | 22 | 60 | | | | |
| 8 | 35 | 9 | Yes | 61 | 28 | 66 | | | | |
| 9 | 52 | 55 | Yes | 124 | 22 | 82 | | | | |
| 10 | 35 | 58 | Yes | 110 | 26 | 48 | | | | |
| 11 | 23 | 74 | Yes | 114 | 19 | 74 | | | | |
| 12 | 44 | 35 | No | 112 | 20 | 59 | | | | |
| Mean | 40 | 37.3 | – | 91.5 | 24.2 | 59.6 | | | | |
| a Data unavailable, patient placed on ECMO at referring center prior to arrival. | | | | | | | | | | |

| Table 2 – ECMO characteristics & outcomes. | | | | | | | | | |
|--------------------------------------------|------|---------------------|---------------------------|----------------------------------------|----------|--|--|--|--|
| Patient ECMO | Type | ECMO Run (Hr) | OR Trips on ECMO | pRBC Transfusion on ECMO (mL) | Survival | | | | |
| 1 | VV | 692.5 | 6 | 40596 | Yes | | | | |
| 2 | VVA | a | 1 | 4800 | No | | | | |
| 3 | VV | a | 1 | 17932 | Yes | | | | |
| 4 | VV | 567.5 | 3 | 28348 | Yes | | | | |
| 5 | VVA | 121.75 | 0 | 2229 | No | | | | |
| 6 | VV | 262.75 | 0 | 5007 | Yes | | | | |
| 7 | VV | 253 | 2 | 3813 | Yes | | | | |
| 8 | VV | 138.5 | 1 | 3860 | Yes | | | | |
| 9 | VV | 157 | 3 | 13478 | No | | | | |
| 10 | VV | 365 | 10 | 58086 | No | | | | |
| 11 | VA | 299.5 | 9 | 31059 | Yes | | | | |
| 12 | VV | 112.5 | 0 | 1200 | Yes | | | | |
| Mean | – | 258 | 3 | 17534 | – | | | | |

a Data unavailable, patient placed on ECMO at referring center prior to arrival.

Burn Unit over an approximately five-year period. This study was approved by the University of Chicago Institutional Review Board (IRB 22–1040). Between April 1, 2017 and June 30, 2022, 12 burn patients were placed on ECMO due to hypoxemic respiratory failure refractory to standard supportive care (Table 1). The average burn size was 37.3% TBSA and 83.3% were diagnosed with a concomitant inhalation injury. On average patients were 40 years old (range 20–69), and 75% were male. Of note, no patients were ventilated in the prone position prior to ECMO initiation due the location of their burn/ graft sites.

In our cohort, nine patients received venovenous (VV) ECMO, two received veno-venoarterial (V-VA) ECMO, and one received venoarterial (VA) ECMO (Table 2). All patients met criteria for severe ARDS and had Murray scores> 3, suggesting that the severity of ARDS at the time of ECMO initiation was consistent with that used in the non-burn ECMO literature [[6](#page-3-0)]. The average duration of ECMO was 258 h, or 10.75 days (range 112.5 – 692.5 h). Patients underwent a median of one debridement and/or grafting procedure prior to ECMO initiation (IRQ=1.75) and a median of 1.5 debridement and/or grafting procedures while on ECMO (IQR=3). A median of 17.9 liters of blood was transfused while on ECMO (IQR=47.7).

In total, eight patients (66.7%) survived to hospital discharge. Of the nine patients on VV ECMO, seven (77.7%) survived and of the three on either VA or V-VA ECMO, one survived (33.3%). The average estimated in-hospital mortality among our patients based on APACHE II scoring was 40.0% [[7](#page-3-0)] and the revised Baux score predicted a 40.2% mortality rate [[8](#page-3-0)]. Among non-survivors, causes of death included transition to comfort care (n = 2), thrombotic occlusion of the ECMO circuit (n = 1), and cardiac arrest (n = 1). Our survival rate is favorable when compared to larger published series [[5,9](#page-3-0)]. We believe that careful patient selection, early identification of patients who fail traditional ARDS management, and timely communication with our multidisciplinary ECMO team contributed to our outcomes.

Our data suggest that, in selected patients, ECMO for respiratory support in adult patients with burn injury is feasible. Our lower-than-expected mortality relative to existing data suggest that ECMO may improve survival in burn patients even when the duration of ECMO support was long and multiple debridement procedures were required. Our findings are limited by their retrospective nature, heterogeneity of patients and practice patterns, and variable availability of ECMO expertise. Future work should focus on establishing larger registries and multicenter studies to clarify indications and outcomes in burn patients with refractory ARDS.

### **Funding**

This research did not receive any specific grant from funding agencies in the public, commercial, or not-forprofit sectors.

## **Conflicts of interest**

None.

REFERENCES

- [1] Meyer NJ, Gattinoni L, Calfee CS. Acute respiratory distress syndrome. Lancet 2021;398(10300):622–37.
- [2] Zuo KJ, Medina A, Tredget EE. Important Developments in Burn Care. Plast Reconstr Surg 2017;139(1):120e–38e.
- [3] Shah A, Pedraza I, Mitchell C, et al. Fluid volumes infused during burn resuscitation 1980-2015: A quantitative review. Burns 2020;46(1):52–7.
- [4] Rasmussen J, Erdogan M, Loubani O, et al. Successful Use of Extracorporeal Membrane Oxygenation Therapy in Patients With 80% Full Thickness Burns. J Burn Care Res 2021;42 (2):345–7.
- [5] Nosanov LB, McLawhorn MM, Vigiola Cruz M, et al. A National Perspective on ECMO Utilization Use in Patients with Burn Injury. J Burn Care Res 2017;39(1):10–4.
- [6] Peek GJ, Mugford M, Tiruvoipati R, et al. Efficacy and economic assessment of conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multicentre randomised controlled trial. Lancet 2009;374(9698):1351–63.
- [7] Knaus WA, Draper EA, Wagner DP, et al. APACHE II: a severity of disease classification system. Crit Care Med 1985;13(10):818–29.
- [8] Osler T, Glance LG, Hosmer DW. Simplified estimates of the probability of death after burn injuries: extending and updating the baux score. J Trauma 2010;68(3):690–7.
- [9] Burke CR, Chan T, McMullan DM. Extracorporeal Life Support Use in Adult Burn Patients. J Burn Care Res 2017;38 (3):174–8.

FoucheTom W. Fouché a a *Pritzker School of Medicine, University of Chicago, Chicago, IL, USA*

Sebastian Q. Vrouwe b , Lawrence J. Gottlieb b b *Section of Plastic & Reconstructive Surgery, University of Chicago, Chicago, IL, USA*

Tae H. Song c c *Section of Cardiac Surgery, University of Chicago, Chicago, IL, USA*

Sachin Mehta d , Avery Tung d , EstiméStephen R. Estimé d,⁎ d *Department of Anesthesia & Critical Care, University of Chicago, Chicago, IL, USA E-mail address:* [sestime@uchicago.edu](mailto:sestime@uchicago.edu) (S.R. Estimé)

Accepted 29 October 2022

<https://doi.org/10.1016/j.burns.2022.10.003> 0305-4179/ © 2022 Published by Elsevier B.V.

⁎ Correspondence to: Department of Anesthesia & Critical Care, University of Chicago, 5841 S. Maryland Ave., MC 4028, Chicago, IL 60637, USA.

Burns

publisher

articletitle

journaltitle

articlelink

content_type

copyright

Acute respiratory distress syndrome

Lancet

Important Developments in Burn Care

Plast Reconstr Surg

Fluid volumes infused during burn resuscitation 1980-2015: A quantitative review

Successful Use of Extracorporeal Membrane Oxygenation Therapy in Patients With 80% Full Thickness Burns

J Burn Care Res

A National Perspective on ECMO Utilization Use in Patients with Burn Injury

Efficacy and economic assessment of conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multicentre randomised controlled trial

APACHE II: a severity of disease classification system

Crit Care Med

Simplified estimates of the probability of death after burn injuries: extending and updating the baux score

J Trauma

Extracorporeal Life Support Use in Adult Burn Patients

Extracorporeal membrane oxygenation utilization in burn patients with severe acute respiratory distress syndrome.

Extracorporeal membrane oxygenation utilization in burn patients with severe acute respiratory distress syndrome

Extracorporeal membrane oxygenation utilization in burn patients with severe acute respiratory distress syndrome

Clinical Summary

What was studied

Key findings

Study limitations

Clinical implications

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