Page 631 - ACCCN's Critical Care Nursing

608 S P E C I A LT Y P R A C T I C E I N C R I T I C A L C A R E

Clinical manifestations antivenom may be required until all major symptoms
Funnel-web spider bites are potentially rapidly lethal; have resolved (severe bites often require eight
156,161,162
however, only 10–20% of bites result in systemic enven- ampoules). The antivenom dose for children is
156,161,162
omation, with the majority being minor and not requir- the same as the adult dose. First aid measures
ing antivenom. The bite is extremely painful, and fang such as a pressure immobilisation bandage can be
marks may be seen. Signs and symptoms of systemic removed after antivenom administration and the symp-
156
envenomation may appear within 10 minutes, and toms have stabilised; this may take several hours.
include perioral tingling and tongue fasciculation; Snake Bites
increased salivation, lacrimation, piloerection, sweating;
nausea, vomiting, headache; hypertension, tachycardia; Description and incidence
dyspnoea, pulmonary oedema; and irritability, decreased The Australian continent is inhabited by a large number
consciousness and coma. 156,162 Regardless of the presence of snakes (over 140 recognised snakes from 30 different
of symptoms, all possible funnel-web spider bites are species; 25% of all known venomous snakes, and 40% of
managed as a medical emergency. 156 all dangerous front-fanged snakes). 151,163 New Zealand
151
Assessment has no known venomous terrestrial snakes. Australian
Patients with suspected funnel-web spider bites are venomous snakes are found in both rural areas and resi-
dential and metropolitan areas, especially when in close
rapidly assessed for presence of any signs and symptoms proximity to bushland and in periods of drought. Distri-
of envenomation and allocated an ATS triage category of bution is within known geographical areas, and nurses
1–3, based on presenting symptoms. A pressure immo- require familiarity with the venomous snakes that inhabit
bilisation bandage is applied if this was not used during their locality of practice. The incidence of snakebite is
first aid. Patients with signs of envenomation are moved estimated at 500–3000 each year, with approximately
to a resuscitation area for immediate treatment, including 200–500 cases requiring treatment with antivenom. 164
urgent antivenom administration and management of There are on average 1–3 deaths per year, although this
the clinical effects of envenomation. Monitoring and may be higher due to unrecognised snake bites. 164
assessment for potentially serious manifestations focus
on ABC: Clinical manifestations
l airway compromise due to decreased level of con- The majority of snake bites do not result in significant
sciousness requiring airway protection with an airway envenomation. 165 Bites are generally recognised by the
adjunct or endotracheal intubation patient at the time because of associated pain, although
l breathing for respiratory compromise due to pulmo- some bites are unrecognised. The bite site may show
nary oedema, requiring CPAP or intubation/ventilation minimal to obvious signs of punctures or scratches, with
with PEEP (see Chapter 13) accompanying swelling and bruising. Multiple bites are
l circulatory compromise due to profound hypotension possible and are generally associated with major enven-
(although this is a late sign and hypertension is more omation. 156,165 Australian snake venoms contain a number
commonly seen), requiring IV access and volume of various toxins that are responsible for the systemic
replacement. Circulatory compromise/failure may effects 156,165,166 (see Table 22.11). Renal damage may occur
lead to cardiac arrest requiring cardiopulmonary as a consequence of myoglobinuria from severe rhabdo-
resuscitation (see Chapter 24). myolysis or haemoglobinuria associated with coagulopa-
thies, 165 leading to acute renal failure (see Chapter 18). 164
All patients require full monitoring with constant nursing
observation. A patient with no signs of envenomation on Assessment
arrival has a detailed history taken regarding the circum-
stances of the bite, the time, description of spider and any Patients presenting with snake bite(s) are allocated a high
first aid undertaken. The patient is then regularly assessed priority for assessment and treatment even if they appear
for any symptoms suggesting systemic envenomation. well on arrival. Patients who present without effective
After thorough medical assessment, if there are no signs first aid measures (the application of a pressure immo-
of systemic envenomation, any first aid such as a pressure bilisation bandage and splint) have these applied imme-
immobilisation bandage is removed and the patient diately. 165 The pressure immobilisation bandage is applied
observed for 6 hours. 156 With no diagnostic test for with a broad (15 cm) crepe bandage, commencing over
funnel-web spider envenomation and no venom detec- the bite site with the same pressure that would be used
tion procedure available, 156 clinical diagnosis is based on for a sprained ankle. The bandage is then extended to
the history and symptoms. cover the whole limb, including fingers/toes, and the
167
Management limb is splinted and immobilised. Correct application
of the pressure bandage is important, as any benefit is
For signs of systemic envenomation, two ampoules of lost with bandages that are too loose, not applied to the
167
funnel-web spider antivenom is administered slowly IV whole limb, or with no splinting or immobilistaion.
over 15–20 minutes; 161,162 premedication is not required, 156 Elasticised bandages are superior to crepe bandages in
although the patient is observed closely for anaphylaxis. obtaining and maintaining adequate pressure. 168 Do not
In severe envenomation associated with dyspnoea, pul- wash the wound prior to applying the pressure immobili-
monary oedema or decreased LOC, the initial antivenom sation bandage, as swabbing of the bite site is used when
dose should be doubled to four ampoules. 161,162 More performing venom detection. The patient should not