Organ protection after severe thermal burns with adenosine, lidocaine, and magnesium (ALM) resuscitation in a rat model

Dr Lisa Davenport1, Dr Hayley Letson2, Professor  Geoffrey Dobson2

1Townsville University Hospital, , Australia, 2Heart and Trauma Research Laboratory, James Cook University, Townsville, Australia

Abstract:

Introduction
The resuscitation of severe burns presents a complex challenge of balancing adequate organ perfusion without causing fluid overload. Adenosine, lidocaine and magnesium (ALM) resuscitation therapy has been shown be organ protective against haemorrhagic shock and traumatic injury. This study aimed to investigate the protective effects of small-volume ALM fluid resuscitation in a 30% TBSA thermal injury rat model.

Methods
Male Sprague-Dawley rats (320–340g; n=25) were randomly assigned to: 1) Sham (surgical instrumentation, without burn, n=5), 2) Saline resuscitation group (n=10), or 3) ALM resuscitation group (n=10). Treatments were initiated 15-min after burn trauma, including 0.7ml/kg 3% NaCl±ALM bolus and 0.25-0.5ml/kg/hr 0.9% NaCl±ALM drip, with animals monitored to 495-min post-burn. Survival, haemodynamics, cardiac function, haematology and histopathology were assessed.

Results
Survival was equivalent with one death from burn shock in each treatment group. ALM improved cardiac function, attenuated the early leukocyte response, and significantly reduced pulmonary oxidative stress (p=0.023). In addition, ALM significantly reduced histological injury scores of lung (Sham 3±1, Saline 14±2, ALM 5±1; p<0.05) heart (Sham 1±0, Saline 8±0, ALM 2±1; p<0.05) and gut injury (Sham 0±0, Saline 6±1, ALM 2±0; <0.05).

Discussion
Previous trauma studies have demonstrated increased survival with ALM resuscitation. In this study, ALM’s therapeutic efficacy may have been reduced by high circulating levels of alpha 1-acid glycoprotein (AGP) which has strong lidocaine-binding properties. Post hoc analysis showed 1.6-fold higher AGP following burn trauma compared with previous ALM trauma and haemorrhage studies (p<0.05).

Conclusions
We conclude that small-volume ALM therapy improved cardiac, lung, gut and immunomodulatory function following severe burn trauma. However, further studies assessing higher ALM doses with longer monitoring periods are required to determine the potential protective effects of ALM in severe burns.


Biography:

Lisa Davenport is a Junior doctor at Townsville University Hospital. Lisa completed her Bachelor of Medicine and Surgery at James Cook University with her honours project focused on preclinical burns research.
Since completing her degree, she has continued to pursue her research interests in burns care.

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