Investigating pressure bandaging for snakebite in a simulated setting: bandage type, training and the effect of transpor

1. Investigating pressure bandaging for snakebite in a simulated setting: bandage type, training and the effect of transport Elizabeth Canale, Medical student Geoffrey K Isbister FACEM, MD, Associate Professor Bart J Currie FRACP, DTM+H, Professor in Medicine and Head of the Tropical Toxinology Program, Menzies School of Health Research, Charles Darwin University and Northern Territory Clinical School, Royal Darwin Hospital, Darwin, Northern Territory Intro Controversy surrounding PIB Sought to discover -if it could be applied correctly in a controlled non-panic situation -based on known parametersIntro Controversy surrounding PIB Sought to discover -if it could be applied correctly in a controlled non-panic situation -based on known parameters

2. Pressure-immobilisation bandage the entire limb AND apply a splint tight as for ankle sprain (?) must immobilise : no walking, even with upper limb bites Traditional NHMRC advice re PIB Direction doesn�t matter: Australian resus council 2005 tip to torso or bite site and aboveTraditional NHMRC advice re PIB Direction doesn�t matter: Australian resus council 2005 tip to torso or bite site and above

3. Previous Knowledge 1979 �PIB formally endorsed by the Aust NHMRC 1979 �Pressure estimated to be 55+/-5 mmHg 1981 �Experiments conducted on Macaca fascicularis 1982/3 �Experiments on humans fail to demonstrate efficacy 1994 �Pressure requirements defined for humans 2005 �Confusion surrounding PIB demonstrated in the US 2008 �Training does not improve long term ability (India) 2008 �This study Slow progress 10 year gaps 55+/-5 Lancet Norris and Ngo 2005 US study India- Simpson and TanwarSlow progress 10 year gaps 55+/-5 Lancet Norris and Ngo 2005 US study India- Simpson and Tanwar

4. Objectives To determine: if pressure bandages can be applied at the correct pressure by a RANGE OF POPULATIONS which bandage TYPE is most appropriate what OPERATOR FACTORS influenced the quality of the bandage whether TRAINING improved the chance of the bandage being applied at the correct pressure. We chose exposed groups Darwin based programWe chose exposed groups Darwin based program

5. Methods Human volunteer study Subjects were asked to apply a pressure bandage to a human lower limb in a simulated setting of a snakebite. Major Outcome: the pressure generated on the limb by the application of the bandage Four parts of the study Pilot study Bandage ability Training efficacy: Immediate Maintenance in transitPilot study Bandage ability Training efficacy: Immediate Maintenance in transit

6. Study Subjects 96 recruited in total 60 health care professionals who did only Study 1 18 health care professions: 3 groups of 6 (Study 1 + 2) medical practitioners (intern or higher) nurses ambulance officers 18 general public in 3 groups of 6 (Study 1 + 2) snake handlers general public (metropolitan) general public (rural areas)

7. Methods The study was conducted in 4 parts: Pilot Study: Bandage TYPE applied by one person to a dummy arm and a human leg on 30 occasions for each material. Best material then compared to traditional crepe. Study 1 (all volunteers): RANGE of populations: health professionals, snake handlers, general population Each asked to bandage a leg with an elasticized sports bandage and a crepe bandage. Randomized to order. Participants unaware of optimal pressure range: 55mmHg to 70mmHg

8. Methods Study 2: Effect of TRAINING Elasticised bandages used over 4 further attempts and participants were told pressure readings. They were then assessed on their 6th attempt using the same pressure outcomes. Study 3: Effect of AMBULANCE travel 2 subjects (4 legs) bandaged at correct pressures. Ambulance driven for 30 minutes on sealed roads and pressure recorded every 5min with a digital pressure transducer

9. MEASUREMENT TECHNIQUE Paediatric blood pressure bladder attached to the standard inflation bulb and a Druck 705 pressure transducer. Taped approximately 75 mm from the knee cap on the lateral front of the lower leg Drawbacks: made it fairly obvious that they had to bandage at least to the knee Did not measure evenness or the entire leg: but we wouldn�t have been able to reflect on the impact of this anywayDrawbacks: made it fairly obvious that they had to bandage at least to the knee Did not measure evenness or the entire leg: but we wouldn�t have been able to reflect on the impact of this anyway

10. Results � Pilot Study Arm: data suggested lots of options were adequate Leg: The majority truly do fall shortArm: data suggested lots of options were adequate Leg: The majority truly do fall short

11. Results �Study 1 Crepe bandage (orange): median pressure was 28mmHg (IQR:17-42mmHg) Elasticized sports bandage (green) median pressure was 47mmHg (IQR:26-83mmHg) 96 participants randomized to first material96 participants randomized to first material

12. Results �Study 2 Training: median pressure was 65mmHg(IQR:56-71mmHg), closer to the optimal range than initial attempts. Initial: 5/36 (14%) achieved optimal pressure compared to 18/36 (50%) after training (p=0.002) 36 participants All training involved Elasticized bandages36 participants All training involved Elasticized bandages

13. Results �Study 3

14. Summary Pressure immobilization is difficult to apply, even in an aware subset of the population. Training helps somewhat, but other studies suggest that the benefit is not long term. Even if correct bandaging is applied the simulation suggests that bandaging will not maintain pressure within the correct range during an ambulance ride.

15. Acknowledgments