IMMEDIATE FIRST AID
for bites by
In the event of an actual or probable bite from a Gaboon Viper, execute the
following first aid measures without delay.
- Make sure that the responsible snake or snakes have been appropriately
and safely contained, and are out of danger of inflicting any additional
- Immediately call for transportation.
- Keep the victim calm and reassured. Allow him or her to lie flat and
avoid as much movement as possible. If possible, allow the bitten limb to rest
at a level lower than the victim's heart.
- Immediately wrap a large crepe bandage snugly around the bitten limb
starting at the site of the bite and working proximally up the limb (the full
length if possible). The bandage should be as tight as one might bind a
- Secure the splint to the bandaged limb to keep the limb as rigid and
unmoving as possible. Avoid bending or moving the limb excessively while
applying the splint.
- DO NOT remove the splint or bandages until the victim has reached the
hospital and is receiving Antivenom.
- Have the SAIMR (South African Institute for Medical Research)
polyvalent antivenom ready for the Lifeflight crew to take with the victim to
the hospital. Give them the following:
- the available antivenom (at least 10 vials)
- the accompanying instruction (Protocol) packet
- the victim's medical packet
DO NOT cut or incise the bite site
DO NOT apply ice to the bite site
Summary for Human Bite
The bite of the Gaboon Viper with subsequent envenomation is a medical
emergency and can be fatal if the patient is not treated appropriately. Please
read the attached Medical Management Protocol and respond
- First Aid:
- Bandage and immobilize the bitten limb with crepe
bandages and splint as described in the Immediate First Aid section. Rest
this extremity below the level of the patient's heart (if practical).
- Transport to U.C.S.D. Medical Center Trauma Service.
- Medical Management:
- Call your local Poison Control Center, or the San Diego Regional
Poison Control Center (800 876-4766). They should locate a consultant to help
you treat this patient.
- Observe for Signs and Symptoms of Envenomation.
- If significant systemic signs or symptoms are present, perform the
- Administer Lactated Ringers Solution at 200 to 250 mls per
- Draw samples and collect initial laboratory data.
- Dilute the contents of 5 vials of SAIMR Polyvalent Antivenom in
Lactated Ringers Solution to a total volume of 300ml. Administer the antivenom
I.V. piggyback over 75 minutes at a rate of 240ml/hour (i.e. one vial per 15
minutes). The combined rate of diluted antivenom and Lactated Ringers Solution
is now approximately 500ml/hour. The rate of Lactated Ringers Solution may be
adjusted accordingly to avoid fluid overload, however a brisk urine output
should be a treatment goal.
- When one complete vial has been infused (i.e. 15
minutes, 60 cc), remove the splints and crepe bandage slowly over a period 10 minutes. If symptoms progress rapidly,
reapply the bandage, wait 10 minutes, and then again release the bandage slowly
over 10 minutes while antivenom administration is continuing.
- Allergic or untoward reactions to the antivenom
should be treated with Benadryl, Epinephrine, and/or Corticosteroids.
A patient with known sensitivity to horse serum may be pretreated with 1 gm of
Solumedrol, administered I.V. push.
- Monitor Signs, Symptoms, and Laboratory data, and administer
additional antivenom in 1 vial increments at a rate of one vial every 15
minutes as necessary to control the progression of symptoms.
- The required amount of antivenom will vary with
the severity of envenomation. One should anticipate using (including the
- 5 vials for a minor bite with envenomation
- 10 vials may be necessary for moderate or severe bites.
for bites by
This person has received a bite and probable envenomation from a Gaboon
Viper (Bitis gabonica). This is a very venomous and dangerous snake native to
high rainfall areas of West, Central, and East Africa. Although there are no
documented deaths from the bite of the Gaboon Viper, many of the complications
from envenomation are life threatening.
Please read and execute the following procedures without delay.
- A crepe bandage and splint have been applied as immediate first aid
adjuncts to retard the absorption of the venom. DO NOT remove until the
patient has arrived at the hospital and is receiving the antivenom.
- Make sure 10 vials of SAIMR Polyvalent Antivenom are present with the
patient. This antivenom is specific and is only available directly from the
San Diego Zoo Reptile Department. Refrigerate the antivenom upon arrival to
- If the patient has been envenomated, the treatment is at least 5 vials
of intravenous antivenom. Envenomation is diagnosed by the presence of
characteristic signs and symptoms. Necessary information follows and is
organized into the following sections:
- Signs and Symptoms of Envenomation
- Medical Management
- General Considerations
- Special Considerations
Signs and Symptoms of Envenomation:
- Local Affects:
- Pain and swelling: onset almost immediately after bite
- Blistering, bleb formation
- Hemorrhagic edema
- Tissue necrosis: onset usually days after bite
- Severe Hypotension: onset immediately
- Cardiac arrythmias:
- Prolonged QT intervals
- Supraventricular tachycardia
- Inverted T waves
- Cardiac arrest
- Coagulation defects
- Spontaneous bleeding:
- Mucosal bleeding
- Gastrointestinal bleeding
- Internal hemorrhage
- Pulmonary edema
- Renal failure
- Abdominal pain
- Regional Lymphadenopathy
- Fang Marks: The presence of fang marks does not always
imply envenomation as the Gaboon Viper is known to bite without injecting
venom into the victim. However, the absence of fang marks does not necessarily
preclude the possibility of a bite, nor does it give any indication of the
severity of the bite. Fang marks may be present
as one or more well defined punctures, as a series of small lacerations or
scratches, or there may not be any noticeable or obvious markings where the
bite occurred. Finally, multiple bites inflicted by a single snake are
possible and should be noted if present.
Those signs and symtoms which give strong evidence for systemic
envenomation include hypotension, dyspnea, cardiac arrythmias, spontaneous
bleeding, and local swelling of more than half the affected limb. Antivenom
should be administered without delay in such cases.
- Admit patient to the Trauma Service and call consultants listed on the
last page. Terence M. Davidson, M.D. is the local consultant for snake bites,
and should be notified immediately.
- Begin a peripheral intravenous infusion (16 gauge catheter) of Lactated
Ringers Solution at a rate of 250 cc/hour.
- Draw blood from the contralateral arm, and collect urine for the
following laboratory tests. Mark STAT.
- Type and Cross Match TWO units of Whole blood.
- CBC with differential and quantitive platelet count.
- Coagulation Parameters:
- Prothrombin Time (PT)
- Partial Thromboplastin Time (PTT)
- Fibrinogen Levels
- Fibrin Degradation Products
- Serum Electrolytes, BUN/Creatinine, Calcium, Phosphorus.
- Lactate Dehydrogenase (with Isoenzyme analysis). Isoenzyme analysis
may indicate multiple targets of the venom components which may dictate further
- Urinalysis (Macroscopic and Microscopic Analysis).
Must include analysis for:
- Free Protein
- Electrocardiogram (Sinus Tachycardia would be expected).
- Continuous Urine Output Monitoring (In-dwelling Foley
Catheter if unconscious). Watch for possible oliguria or anuria.
- Additional tests as needed or indicated by the patient's hospital
- The patient's vital signs should be monitored frequently over the
first 48 hours after the bite for evidence of circulatory shock.
- It may be necessary or practical to repeat some of the above serum and
urine tests over the hospital course to monitor the effects of antivenom
therapy or to detect late changes in laboratory values.
- OBSERVE PATIENT CLOSELY for signs and symptoms of envenomation which
usually manifest between 15 minutes and two hours after the bite
- If NONE of the signs or symptoms have been noted after TWO hours,
there is the possibility that the patient received a dry bite (no venom
- VERY SLOWLY begin to remove the bandages and splint watching carefully
for any changes in the patient's status. If any changes occur, assume the
patient has been envenomated and prepare to give antivenom immediately (as
- If signs and symptoms still fail to manifest, continue CLOSE
observation of the patient for an additional 12 to 24 hours.
- IF SIGNIFICANT SYSTEMIC SIGNS OR SYMPTOMS become apparent, begin
antivenom therapy as follows:
- Dilute the contents of 5 vials of SAIMR Polyvalent
Antivenom in Lactated Ringers Solution to a total volume of 300ml.
Administer the antivenom I.V. piggyback over 75 minutes at a rate of 240ml/hour
(i.e. one vial per 15 minutes). The combined rate of diluted antivenom and
Lactated Ringers Solution is now approximately 500ml/hour. The rate of
Lactated Ringers Solution may be adjusted accordingly to avoid fluid overload,
however a brisk urine output should be a treatment goal.
- Should any signs of ALLERGY/ANAPHYLAXIS (e.g., coughing, dyspnea,
urticaria, itching, increased oral secretions, etc.) develop, immediately
discontinue the administration of antivenom, and treat symptoms with
Corticosteroids, Epinephrine, Benadryl, Atarax and/or Antihistamines. As soon
as the patient is stabilized, continue the antivenom infusion at a slower rate.
- After 15 minutes of antivenom administration, the
splint and the bandages may be removed. This should be done VERY SLOWLY
over a period of 10 minutes to prevent a bolus release of venom. If the
patient's condition worsens, reapply the crepe bandage, wait 10 minutes and
release the bandage again slowly over 10 minutes while antivenom administration
- Antivenom Therapy is the mainstay of treatment for Gaboon Viper snake
envenomation. Many of the symptoms are ameliorated or entirely eliminated by
the antivenom alone. Other symptoms will require additional therapeutic
modalities in order to be corrected.
- Cardiovascular status: Gaboon Viper venom is known to be cardiotoxic
and causes arrythmias as well as decreases in stroke volume and cardiac output.
In addition the venom results in a lowering of peripheral vascular resistance
and thus gives rise to hypotension. The administration of antivenom alone will
dramatically improve hypotension and signs of circulatory shock provided the
patient is not volume depleted. Intravenous administration of Lactated Ringers
Solution is warranted if the patient is hypovolemic but is only efficacious if
antivenom has been administered. Cardiac arrythmias, specifically prolonged
QT intervals, inverted T waves, and supraventricular tachycardia may persist
for days after the initial envenomation. Severe arrythmias may require the use
of a temporary pacemaker to ensure adequate cardiac output and to prevent
- Hematological signs and symptoms: Gabbon Viper venom has a
thrombin-like enzyme which quickly depletes serum fibrin levels thus rendering
the blood incoagulable. In addition the venom has hemorrhagic activity as it
causes widespread damage to the microvasculature. Of note, the lungs and
gastrointestinal tract are extremely sensitive to this hemorrhagic activity.
Finally, disseminated intravascular coagulopathy and anemia may also occur.
The patient should be monitored closely and blood products including whole
blood, packed RBC's platelets, cryoprecipitate, and fresh frozen plasma should
be given when indicated.
- Pulmonary: The hemorrhagic activity of the venom results in
pulmonary edema, tachypnea, and dyspnea.
- Renal: The hemorrhagic activity of Gaboon Viper venom may result in
hematuria. In addition, hemoglobinuria and myoglobinuria may likewise affect
renal function, and if severe, (Acute Renal Failure), may necessitate
- Laboratory: Gaboon Viper venom has been noted to cause transient
increases in serum SGOT, SGPT, and LDH levels suggesting damage to liver and
- Neurological symptoms are uncommon with Gaboon Viper bites.
Respiratory distress is nearly always secondary to pulmonary edema rather than
- It is important to keep venom neutralization current and continuous.
The best method to accomplish this is to monitor the patient's status. If the
present condition does not improve, or should it worsen for any reason,
additional antivenom should be administered. Give all additional antivenom in
one vial increments. Dilute the antivenom in Lactated Ringers as before and
administer the antivenom I.V. piggyback over approximately 15 minutes.
BITES WITH ENVENOMATION REQUIRE AT LEAST 5 VIALS BUT SEVERE ENVENOMATIONS
MAY REQUIRE UP TO 10 VIALS OF ANTIVENOM.
- It is advisable to perform periodic serum and urine analyses during
therapy (as outlined above).
- It is always best to keep the patient in an Intensive Care setting
until free of major symptoms for 24 hours. The patient should be observed in
the hospital for at least 24 hours after all symptoms abate.
- It is important that the patient remain resting and warm. Avoid
- Symptom variability: As noted already there is marked symptom
variability in response to a Gaboon Viper bite. It is important to note the
progression of symptoms throughout the course of therapy and give additional
antivenom as necessary to titrate these symptoms.
- Respiratory Failure: Pulmonary edema and subsequent dyspnea may
necessitate the use of supplemental oxygen. If severe, the use of a ventilator
may be indicated.
- Cardiac Arrest: The cardiotoxic nature of Gaboon Viper venom
necessitates careful monitoring of the patient's cardiac status the first 24-48
hours after envenomation.
- Fluid Management: The patient should be well hydrated, and a
brisk urine output should be maintained. Blood products should not be given
until circulating venom has been neutralized with antivenom.
- Compartment Syndrome: It should be noted that fascial
compartment syndromes in Gaboon Viper bites are uncommon. Limbs may swell
significantly, but rarely involve specific fascially bound compartments. If
however the logistics of the bite raise a high index of suspicion for a
compartment syndrome, monitoring with a Wick Catheter or appropriate pressure
device may be necessary. Fasciotomy is rarely, if ever, recommended in these
- Tetanus Prophylaxis should be current.
- Antibiotics are not recommended prophylactically.
- Antivenom is the best treatment for all signs and symptoms of
Gaboon Viper bites and should be utilized prior to other treatment
- Multiple Bites:
1. It is possible for a Gaboon Viper to deliver more than one bite in a
single attack. If there is evidence that such an attack occurred (i.e.,
history or multiple bite sites), give the initial dose of 5 vials but be
prepared to give a total of 10 vials to adequately treat the bite. Titrate
antivenom administration to signs and symptoms as discussed previously.
- Testing for Equine Protein Sensitivity:
- It is NOT ADVISABLE to utilize subcutaneous or intradermal testing
for sensitivity to equine products in that such testing may be unreliable, and
may unnecessarily delay antivenom therapy which must be used if any signs of
Gaboon Viper envenomation are present.
- If there is reason to believe that the patient may be sensitive to
equine protein products:
- Premedicate the patient with 1 gm Solumedrol,
administered I.V. push. Assuming the patient's condition is stable,
wait 15-30 minutes before
administering the antivenom.
- Administer the diluted antivenom at a rate as
tolerated by the patient beginning at a rate of
120ml/hour (as opposed to the normal 240ml/hour rate). If the patient
tolerates this, increase the rate up to 240ml/hour.
- Monitor Pulse and Blood Pressure carefully. Be prepared to
treat for Anaphylaxis.
- Clinical Experience with the Gaboon Viper:
- There are very few documented cases of Gaboon Viper bite envenomation
in the literature. As such, other complications of envenomation may occur
which have previously not been described.
- The Gaboon Viper (Bitis gabonica) is considered to produce more venom
than any other venomous snake. A single adult animal may have enough venom to
inject lethal doses into 30 individual men. Despite these statistics, the
Gaboon Viper is noted for its docile nature and this may account for the very
few reported bites in the literature. Although no documented deaths have been
attributed to Gaboon Viper bites, the snake should not be considered less
dangerous as many of the complications of envenomation are life
- Prompt recognition of clinical envenomation and adequate amounts of
antivenom delivered early in the treatment course will facilitate a good
recovery. The use of at least 5 vials of antivenom reduces the incidence of
The following references are recommended for further reading. This
material includes case histories, guidelines and recent findings in treatment
of Gaboon Viper bites. These should be read only after treatment has begun,
and the patient is stable.
- Marsh, N.A., Whaler, B.C., The Gaboon Viper (Bitis gabonica): its
biology, venom components and toxinology, Toxicon 22, 669-694, 1984.
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