It is the time of the year when snakebite numbers rise dramatically, making it necessary for both individuals and doctors to refresh their memory of what to do in the event of snakebite.
In an e-mail communication with Ian Simpson, international snakebite expert and snakebite adviser to the Pakistan Medical Research Council (PMDC), ‘The News’ learnt that the bitten limb should be treated like a fracture. It should be immobilise with clothing or cloth but the wound should neither be tightly tied nor cut, sucked or burnt as such actions can actually prove dangerous. “Immediately get the victim to a hospital and make a note of any signs like drooping eyelids, difficulty in speaking or unusual bleeding on the way and tell the doctor,” Ian advised.
The snakebite expert said it is important to keep calm if you or another person is bitten. “Remember that it’s probably a non-venomous species or a dry bite where no venom has entered the system. Most likely, there is nothing to worry about. Tell the victim and reassure them,” he said.
When a snakebite victim gets to the hospital, he will remain there for 24 hours so that the doctor can be sure whether the bite requires anti-venom. This is very normal and nothing to worry about.
For the doctor, it is important to get the right tools to handle snakebite. “In Pakistan, a supply of 10cm glass test tubes that are new, clean, and dry, are vital.
These are inexpensive and allow accurate coagulation tests to be taken by the bedside, which is the key indication if anti-snake venom (ASV) is required in a viper bite. If the blood is still liquid after being undisturbed for 20 minutes, then ASV is required,” Ian disclosed.
In cases of cobra or krait bite, if the victim requires ASV, there will be visible signs such as ptosis, difficulty in breathing or speaking and maybe heaviness of the head showing neurological impairment.
The key indicators of ASV requirement are incoagulable blood or neurological signs. Just because the snake is believed to be poisonous or there is swelling at the bite site, are not grounds to give ASV, Ian informed.
If the bite is from a confirmed saw scale viper, in some parts of Sindh, this is almost certain, then the starting dose of ASV available at the National Institute of Health (NIH) is 4 vials. In all other cases, i.e., unknown envenomation or Indian ASV, the starting dose is 8-10 vials given over 1 hour.
“In the case of a viper bite when the initial ASV is complete, wait 6 hours and give another coagulation test, using a new, glass test tube. If the blood is coagulable, no more ASV is required. If the blood is still liquid, repeat the dose and continue with the
6 hourly tests until coagulation is restored,” Ian advised doctors.
In cobra and krait bites, once the initial dose of ASV is complete, doctors should wait for 1-2 hours and if the symptoms have worsened i.e. the paralysis has descended further, or if they have not improved, give a second dose. Two doses of ASV will be sufficient to neutralise the venom and now ASV therapy is finished.
“The NIH is working to increase the amount of ASV produced but it is still essential that ASV is used effectively and only given to patients who are envenomed, in the correct dosage and stopped when a sufficient amount to neutralise free flowing venom has been given,” Ian said.
It is important to remember that cobra and krait victims actually die because they stop breathing! “If you keep them breathing with a resuscitation bag, particularly if helped by improvised nasopharyngeal airways improvised from size 5 rubber endotracheal tubes, the victim will survive,” Ian informed.
Source: The News, 21/7/2008