Presentation on theme: "Management of Snake Bite Victims with Respiratory Paralysis in ICU"— Presentation transcript:
1 Management of Snake Bite Victims with Respiratory Paralysis in ICU Dr. T.R. ChandrashekarDirector Critical CareK.R.HospitalBangalorePublished byDR TRC/ KRH
2 Management of Snake Bite Victims with Respiratory Paralysis in ICU Facts givenSnake bite which has lead to Respiratory ParalysisPatient in ICUAnswerManagement aspects
3 How to prevent snake bites? A world free of snakesNearly a quarter of us would go hungryAre important elements in the food chain to control the rodent population- Which destroy all major crops.The bottom line is we need snakes to survive
4 EpidemiologyIndia estimates in the region of 200,000 bites and 15-20,000 snake bite deaths per yearOriginally made in the last century, are still quoted. No reliable national statistics are available.Males are bitten almost twice as often as femalesMajority of the bites being on the lower extremities.50% of bites by venomous snakes are dry bites. that result in negligible envenomation.
5 FAB FOURIn India, more than 200 species of snakes but only 52 are poisonous.Saw-scaled viper (Echis carinatus)Russell’s viper (Daboia russelii)Common krait (Bungarus caeruleus)Indian cobra (Naja naja)Majority of bitesNearly 70-80%HemotoxinVasculotoxinNeurotoxic1234
6 Species: Medical Implications Signs/Symptoms and Potential TreatmentsCobraKraitRussell’s ViperSaw Scaled ViperOther VipersLocal pain/ Tissue DamageYesNoPtosis/NeurotoxicityYes!NOCoagulationRenal ProblemsNeostigmine & AtropineNo?
7 Syndromic approach No local signs with Neuro-toxicity- Krait With or with out local signs and Neuo-toxicity-CobraWith or with out Neurotoxicity and local signs and hemotoxicity-Rusell’s ViperLocal signs with hemotoxicity-Saw Scaled Viper
8 Venomous snakes Majority is by non-venomous snakes Snake biteMajority is by non-venomous snakesVenomous snakesAbout 50% of bites are dryAnti snake venomASV -severe adverse reactions, Costly, Limited supply.Used- benefits of ASV treatment is considered to exceedthe risks.
10 Snake bite and Respiratory paralysis More cases why ?NeurotoxicMV for respiratory paralysisASVMV as Supportive careNeuromuscular paralysis-blockade of neuromuscular transmission.Cobra- post-synapticKrait- pre-synapticBulbar paralysis-AspirationSepsis,DIC-shockARF-Pulmonary edema
11 Starts early- many die before they reach hospitals NEUROTOXICITYStarts early- many die before they reach hospitalsMany reverse very well with ASV if started earlyLess number of casesHEMOTOXICITYStarts late hence most of them reach hospitalsMany organ involvement hence MV is mostly supportive to buy time for organs to recoverMore number of cases70-80%20-30%
12 Case scenario…….34 yr old male shifted from rural health center with H/O snake bite 6 hrs back has ptosis, respiratory distress, RR 35/mt, BP 120/60, oral secretions present, absent gag and cough reflex shifted to ICU for teritary care.On ASV 100ml stat, & 50ml in NS over 6 hrsOxygen 3l/mtPatient is comfortable, vitals stableNo ptosis, distressPatient receivedin casualtyPatient is dead –what do you think went wrong ?
13 Patient is dead –what do you think went wrong ? What could have been done better ?Bulbar signs-probably aspirated and diedEndotracheal intubation can be placed on T-piece Ambuing or Transport VentilatorAnticholienesterasesNeostigmine with atropine
14 Case scenario…….34 yr old male shifted from rural health center with H/O snake bite 6 hrs back has ptosis, respiratory distress, RR 35/mt, BP 120/60, oral secretions present, absent gag and cough reflex shifted to ICU for teritary care.On ASV 100ml stat, & 50ml in NS over 6 hrsOxygen 3l/mtWhat are the Management issues?Why doesNeurotoxicity occurASV, Anticholineesterases,MV…
16 Krait- Pre-synaptic action Beta-bungarotoxin- Phospholipases A21) Inhibiting the release of acetylcholine from the presynaptic membrane2) Presynaptic nerve terminals exhibited signs of irreversible physical damage and are devoid of synaptic vesicles3) Antivenoms & anticholinesteraseshave no effectParalysis lasts several weeks and frequently requires prolonged MV. Recovery is dependent upon regeneration of the terminal axon.
17 Cobra –post-synaptic alpha-neurotoxins “Curare-mimetic toxins’’ Bind specifically to acetylcholine receptors, preventing the interaction between acetylcholine and receptors on postsynaptic membrane.Prevents the opening of the sodium channel associated with the acetylcholine receptor and results in neuromuscular blockade.ASV -rapid reversal of paralysis.Dissociation of the toxin-receptor complex, which leads to a reversal of ParalysisAnticholinesterases reverse the neuromuscular blockade
18 Snake envenomation in a north Indian hospital PtosisOphthalmoplegiaBulbar weaknessRSinvolvementN Sharma, S Chauhan, S Faruqi, P Bhat, S Varma, Emerg Med J 2005;22:118–120
19 Neurotoxic envenoming-Examination Ask the patient to look up and observe whether the upper lids retract fully.Test eye movements for evidence of early external ophthalmoplegia .Check the size and reaction of the pupils.Krait can cause fixed, dilated non reactive pupils simulating brain stem death – however, it can recover fullyAsk the patient to open their mouth wide and protrude their tongue; early restriction often paralysis of pterygoid muscles.The muscles flexing the neck may be paralysed, giving the “broken neck sign
20 Bulbar paralysisCan the patient swallow or are secretions accumulating in the pharynx- an early sign of bulbar paralysis?Ask the patient to take deep breaths in and out. “Paradoxical respiration”.Objective measurement of ventilatory capacity is very useful. Use a peak flow metre, spirometer (FEV1 and FVC)Ask the patient to blow into the tube of a sphygmomanometer to record the maximum expiratory pressure (mmHg).
21 Local examinationDuring the initial evaluation, the bite site should be examined for signs of local envenomation (edema, petechiae, bullae, oozing from the wound, etc) and for the extent of swelling.The bite site and at least two other, more proximal, locations should be marked and the circumference of the bitten limb should be measured every 15 min thereafter, until the swelling is no longer progressing.
22 Treatment Anti Snake Venom Polyvalent /Monovalent Dose-large vs small TimingRepeat doseHypersensitivityAnticholinesterases- Tensilon testMechanical ventilation
23 ASVThe decision to treat a snake bite with antivenin is largely based on clinical parameters.Trying to capture, kill, or transport a snake for identification purposes seems of little value and possibly dangerousASV is polyvalentSyndromic approach helps in examination and investigations and outcome predictions
24 Skin testing for ASVSkin/conjunctival hypersensitivity testing does not reliably predict early or late antivenom reactions and is not recommended.
25 What is ASV?Antivenom is immunoglobulin (usually the enzyme refined F(ab)2 fragment of IgG) purified from the serum or plasma of a horse or sheep that has been immunised with the venoms of one or more species of snake.Monovalent or monospecific antivenom neutralises the venomof only one species of snakePolyvalent or polyspecific antivenom neutralises the venoms of several different species of snakesThe ASV that is available in India is a polyvalent type which is active against the commonly found snakes in India including the FAB Four.
26 Indications for ASV Neurotoxicity ARF Bleeding/coagulopathy Myoglobinuria/haemoglobinuriaCardiac toxicityLocal swelling involving more than half of the bitten limbRapid extension of swellingDevelopment of an enlarged tender lymph node draining the bitten limb
27 Timing of ASVThere is no consensus as to the outer limit of time of administration of antivenom. Best effects are observed within four hours of bite .It has been noted to be effective in symptomatic patients even when administered up to 48 hours after bite.Reports suggest that antivenom is efficacious even 6-7 days after the bite from vipersWhen there are signs of local envenoming, without systemic envenoming, antivenom will be effective only if it can be given within the first few hours after the bite
29 Large vs small dose High dose group 100ml stat and 100 ml every 6 hrs Low dose group 100ml stat and 50 ml every 6 hrsUntil recovery of neurological signsLow dose of snake antivenom is as effective as high dose in patients with severe neurotoxic snake envenoming Agarwal, Aggarwal, Gupta, et alEmerg Med J 2005;22:397–399.
30 High vs low ASVWhen a person is bitten by a snake, the major part of thetoxin gets fixed to the tissues and only a relatively smallpart remains in the cirulation by the time the patient isbrought to the hospital.Though it is useful and essential to neutralize thecirculating toxin, it is more important to treat the systemsinvolved effectively and aggressively.
31 Repeat dose Signs of systemic envenoming may recur within 24-48 hrs Criteria for repeating the initial dose of antivenomPersistence or recurrence of blood incoagulability after 1-2 hrDeteriorating neurotoxic or cardiovascular signs after 1-2 hrContinuing absorption- due to improved blood supply following correction of shock, hypovolaemia etc,After elimination of antivenomA redistribution of venom from the tissues into the vascular space.Causes
32 Observation of the response to Antivenom Cobra bites-Post synapticMay begin to improve as early as 30 minutesafter anti-venom, but usually take several hours.Krait and sea snakes- Pre synapticDepends on the timing of ASV administrationIf delayed may not produce any action or Minimal delayed action
33 Antivenom reactionsComplement activation by IgG aggregates or residual Fc fragments or direct stimulation of mast cells or basophils by antivenom protein are more likely mechanisms for these reactions.20%, of patients, usually more than develop a reactionTypesEarly anaphylactic reactions- within minPyrogenic (endotoxin) reactions- develop 1-2 hoursLate (serum sickness type) reactions- develop 1-12 (mean 7) days.Fatal reactions have probably been under-reported asdeath after snake bite is usually attributed to the venom.
34 Antivenom reactions At the earliest sign of a reaction: Antivenom administration must be temporarily suspendedAdrenaline-0.1% solution, 1 in 1,000, 1 mg/ml is the effective treatment for early anaphylactic reactions.IV hydrocortisone (adults 100 mg, children 2 mg/kg body weight). The corticosteroid is unlikely to act for several hours, but may prevent recurrent anaphylaxisThere is increasing evidence for anti H2 antihistamines-Ranitidine – adults 50 mg, children 1 mg/kg.Pyrogenic reactions require- antipyretics.In case of circulatory collapse- start fluids, inotropes along with IV adrenaline5-day course of oral antihistamine/ Prednisolone.Chlorpheniramine: 2 mg six hourly Prednisolone: 5 mg six hourlySerumsickness
35 Trial of anticholinesterase Anticholinesterase (“Tensilon”/Edrophonium) testRecord baseline parametersGive atropine IVGive anticholinesterase drug edrophonium chloride (adults 10 mg, children 0.25 mg/kg body weight) given intravenously over 3 or 4 minutesNeostigmine 25µg/kr/hrNeostigmine 0.5 mg / 6 hrIV atropine 0.5 mg / 12 hrDose of NeostigmineObserveNegative responsePositive responseTearing, salivation,muscle fasciculation, abdominal cramp,bronchospasm, bradycardia, cardiac arrestImprovement in ptosis, Respiratory distress, better cough effort, decrease in RRAtropine IVNeostigmine
36 On ASV 100ml stat, & 50ml in NS over 6 hrs Oxygen 3l/mt 34 yr old male shifted from rural health center with H/O snake bite 6 hrs back has ptosis, respiratory distress, RR 35/mt, BP 120/60, oral secretions present, absent gag and cough reflex shifted to ICU for tertiary care.On ASV 100ml stat, & 50ml in NS over 6 hrsOxygen 3l/mtIs given neostigmine 0.6mg and 0.6 mg atropine ivYou can have alive but a sicker patientCobraYou can have dead patientKrait
37 Shifted to ICU placed on a Ventilator lot of secretions Alive but a sicker patientShifted to ICU placed on a Ventilator lot of secretionsDo we continue anticholinesterases ?Issues to considerIncreased secretionsIncreased incidence of VAP ?We rarely use these drugs once the patient is in the ICU under observation
38 Repeat dose Signs of systemic envenoming may recur within 24-48 hrs Criteria for repeating the initial dose of antivenomPersistence or recurrence of blood incoagulability after 1-2 hrDeteriorating neurotoxic or cardiovascular signs after 1-2 hrContinuing absorption of venom from the “depot” at the site of the bite, due to improved blood supply following correction of shock, hypovolaemia etc,After elimination of antivenomA redistribution of venom from the tissues into the vascular space, as the result of antivenom treatment
39 Mechanical ventilation If patient has respiratory distress or bulbar paralysis-intubate and ventilate.If delayed can cause aspiration or hypoxia and cardiac arrest.Even if the facility for MV is not availableAmbuing can save the day.This helps even during transport.MV is not complicated is like ventilating a patient with curare over-dosage
40 ASV and children Dose of antivenom Snakes inject the same dose of venom into children and adults.Children must therefore be given exactly the same dose of antivenom as adults.
41 Pregnancy and snake bite Pregnant patient is treated the same manner as the nonpregnant patient. Spontaneous abortion, bleeding, fetal death & malformations are common.Lactating mothers can continue lactatingFetal demise is difficult to predict because of associated symptoms, such as coagulopathy or hypotension, and complications of treatment including anaphylaxis.Generally speaking, the severity of the mother's clinical course seems to be the best indicator of the fetal survival.
42 Treatment issues in non Neurotoxic respiratory paralysis Aspiration can complicate MVRespiratory paralysis due to Shock, ARF, Sepsis, etc..MV is instituted to buy time till the organs recoverTreatment is directed towards the causeASVAntibioticsSource control-Fasciotomies ?DialysisInotropesBlood and blood products
43 Mismatched Blood transfusion A 25 yr old male with snake bite has signs of compartment syndrome and the pressure is 60 mmHg is undergoing surgery has a Hb of 6 gm%, is hypotensive 100/60, on noradrenalin, acidotic,coagulation profile is normalBlood is startedAfter 15 mts of surgical time patient developsDark colored urineBp drops to 80/60What are the possibilities ?TreatmentFluids, Mannitol,Alkalinize the urine,Manage electrolytesFasciotomyRRTRhabdomyolysisMismatched Blood transfusion
45 KraitBites by krait, coral snake, and some cobras are associated with minimal local changes;However, bite by the Indian cobra (Naja naja) results in tender local swelling, blistering, and necrosis. Local necrosis causes a picture of wet gangrene with a characteristic putrid smell due to the direct cytolytic action of the venom.Skip lesions are typical findings
46 ViperViper bite is primarily vasculotoxic. It causes rapidly developing swelling of the bitten part.Local necrosis is mainly ischemic as thrombosis blocks the local blood vessels and causes a dry gangrene
47 Clinical features of a compartmental syndrome • Disproportionately severe pain• Weakness of intracompartmental muscles• Pain on passive stretching of intracompartmental muscles• Hypoaesthesia of areas of skin supplied by nerves running through the compartment• Obvious tenseness of the compartment on palpationEarly treatment with antivenom remains the bestway of preventing irreversible muscle damageCriteria for fasciotomy in snake-bitten limbsHaemostatic abnormalities have been corrected (antivenom, with or without clotting factors)• Clinical evidence of an intracompartmental syndrome• Intracompartmental pressure >40 mmHg (in adults)
48 Summary Snake bites may be by an non venomous snake or a dry bite Not all snake bites require ASVASV is the main stay in the treatment of snake bitesASV must be initiated if indicated at the earliestRespiratory paralysis can be because of different reasons-Neurotoxicity, shock, sepsis, ARF…MV may be main stay of treatment or just supportive depending on the cause of failure.
49 Wishing you all a wonderful 2009 Thank youWishing you all a wonderful 2009
50 FasciotomyFasciotomy should not be carried out in snake bite patients unless or until haemostatic abnormalities have been corrected.Clinical features of an intracompartmental syndrome are present and a high intracompartmental pressure has been confirmed by direct measurement
51 Results : In the low-dose group High-Dose Anti-Snake Venom Versus Low-Dose Anti- Snake Venom in The Treatment of Poisonous Snake Bites — A Critical StudyResults :In the low-dose groupMortality rate of 10%, 18% required dialysis and 6% required ventilatory support. LOS 8.42 daysIn the high-dose groupMortality rate of 14%, 26% required dialysis 6% required ventilatory support.LOS 9.02 daysConclusion : While there was no additional advantage in following a high-dose regime for snake bite cases, there was considerable financial gain by following the low-dose regime,Most of the parameters showed a beneficial trend for the low-dose group though the differences were not statistically significantJAPI • VOL. 52 • JANUARY 2004
52 High vs low ASVRepeated high doses of ASV to restore the clotting timeto normal within the shortest time, do not seem to benecessary to reduce the ultimate morbidity and mortality.A smaller dose sufficient to make the clotting time graph take a downward trend is sufficient.The body’s detoxifying system will bring down the clotting time eventually though it may take a slightly longer time.This delay does not seem to affect the morbidity and mortality as shown by the results of this trial.