Much has been written about first aid in the case of snakebites and the most important first aid measure with any snakebite is to promptly and safely get the victim to the nearest hospital.
The majority of snakebites in Southern Africa are from Mozambique Spitting Cobras, Puff Adders and Stiletto snakes. Their venoms are cytotoxic causing severe pain, swelling and in some bites necrosis. Very few victims die and most have ample time to get to a hospital.
Black Mamba and Cape Cobra bites are far more dangerous as their venom is neurotoxic and may affect breathing. These two snakes account for the majority of snakebite deaths in South Africa, around 10 – 12 a year.
Left: Cape Cobra (Naja nivea) Right: Black Mamba (Dendroaspis polylepis)
Other than rapid transport to a hospital there is little one can do for cytotoxic bites, except for immobilisation and slight elevation of the affected limb. For neurotoxic bites one can make use of a pressure bandage and wrap the entire limb as tightly as one would for sprained ankle. The idea is to put pressure on the lymphatic system and to slow down the rate at which venom spreads. The problem with pressure immobilisation is that a specific pressure is required to be affective, something I teach in advanced first aid for snakebite courses. This pressure is in the region of 50 – 70 mm of mercury on a blood pressure monitor and is not easily achieved without training.
Pressure immobilisation being practiced at an ASI Advanced First Aid for Snakebite Course.
In very serious neurotoxic bites the proper use of a bag valve mask reserve, when required, could be life-saving. By using a bag valve mask the victim is manually ventilated. But using a bag valve mask is not easy and training is required.
An ASI course participant learning the correct use of a Bag Valve Mask.
All of the other first aid measures for snakebite emergencies are largely useless. So forget about cortisone, antihistamine and even adrenaline. Not to mention giving pets milk or charcoal or the all-time favourite – Allergex pills. It is a total waste of time.
In serious snakebites, when a lethal amount of venom has been injected into a human of pet, antivenom will be required and in large quantities. Hence the necessity to urgently get to a hospital.
I am often asked whether one can inject antivenom for a snakebite if several hours away from the closest hospital? The simple answer is no and for the following reasons:
We have two antivenoms in South Africa, both produced by the South African Vaccine Producers – a monovalent antivenom that is used for Boomslang bites and a polyvalent antivenom that is manufactured to neutralise the venom of the cobras, mambas, Puff Adder, Gaboon Adder and Rinkhals. The former is rarely used as the Boomslang seldom bite people.
Polyvalent antivenom is packed in 10 ml glass vials, cost around R1,000.00 a vial and in any serious snakebite where antivenom is used, the dosage will be in the region of 10 – 15 vials. It has to be stored in a refrigerator and expires after three years.
When administered, antivenom is usually infused via a saline drip with an initial dosage of anything from 8 – 10 vials. If the recovery is not marked after about 20 minutes, more antivenom is administered. This should be done in a hospital environment where a team is taking care of the patient. The biggest danger is that a large portion of snakebite victims that are treated with antivenom have an allergic reaction. This is partially because antivenom is made from horse blood. Horses are hyper immunised and bled where after the serum is removed from the blood. Most allergic reactions are not too severe but in about 20% of cases where victims are allergic, they go into anaphylactic shock. This is a serious medical condition with the patient’s blood pressure dropping, the throat closes up and the heart soon stops beating. Doctors will immediately inject adrenaline to get the system going again and antivenom treatment stops.
The important aspect of antivenom treatment is that a doctor must first assess the patient and then decide whether antivenom is required or not. Over 80% of all snakebite victims that are hospitalised do not receive antivenom as it is not required. The same applies to pets – a veterinarian needs to do a proper assessment before administering antivenom. Over 98% of snakebite victims that are treated with antivenom in a hospital survive.
Back to the question – if one is several hours away from a hospital, can antivenom be administered? The simple answer is no – it is just too complex. How does a person without a medical background assess symptoms and then administer enough antivenom to neutralise the effects of the venom? And what happens if the patient goes into anaphylactic shock? Too little antivenom (one or two vials) does no good and will not save the victim’s life. In fact it may just be enough to trigger anaphylaxis.
Much of my time is spent in the field and some of the trips are three to four week trips to remote areas. I do carry a bag valve mask but have never carried antivenom and will certainly not use it. It’s just too complicated.
Words and photos – Johan Marais