[ ]
Latest News Updates
Showing posts with label Emergency Medicine. Show all posts
Showing posts with label Emergency Medicine. Show all posts
Medical emergencies in the dental surgery: anaphylactic and anaphylactoid reactions
By Piscean | Sunday, October 2, 2011 | Posted in , , , , | With 0 comments

Medical emergencies  in the dental surgery: anaphylactic and anaphylactoid reactions


General considerations
Anaphylactic (IgE-mediated) and anaphylactoid (pseudoallergic) reactions have overlapping clinical features. Anaphylactic and anaphylactoid reactions usually appear within minutes of parenteral or mucosal exposure to a drug, and around 30 minutes to hours after drug ingestion.

Anaphylactic urticaria and angioedema begin soon after drug exposure. Other features of anaphylaxis include bronchospasm, laryngeal oedema, abdominal cramps, diarrhoea and hypotension.
Anaphylactoid urticaria and angioedema with or without hypotension and bronchospasm similarly present soon after drug administration. Itch and/or urticaria alone can occur in milder presentations, and are more often seen after oral administration; they are occasionally seen following subcutaneous or intramuscular administration.

See Box 13.29 and Appendix 4.1 for management of patients with anaphylactoid or anaphylactic reactions.
Management of anaphylactoid and anaphylactic reactions (Box 13.29) [NB1]

A patient who is known to have an allergy should be instructed to bring their medication with them when they are presenting for dental treatment.

If an anaphylactoid or anaphylactic reaction occurs:
Call 000.
Remove and/or cease allergen.
Cease dental treatment.
Give adrenaline (in doses shown in Appendix 4.1 for management of anaphylactic reaction), either
autoinjector into the anterolateral thigh (through clothes if necessary), or tongue
OR
drawn-up solution into the anterolateral thigh, tongue or floor of mouth.
Give oxygen.
If patient loses consciousness:
Institute basic life support—cardiopulmonary resuscitation (CPR), see Basic life support (Figure 14.3)
Maintain treatment until assistance arrives.
NB1: See Emergency management of anaphylaxis in the community (Appendix 4.1) for further information.

Emergency management of anaphylaxis in the community (Appendix 4.1)
By Piscean | | Posted in , , , | With 0 comments

Emergency management of anaphylaxis in the community (Appendix 4.1)
This chart has been reproduced with permission from Australian Prescriber. It was published as an insert to Australian Prescriber 2007, Vol. 30, No. 5 (http://www.australianprescriber.com/magazine/30/5/artid/913/).
Note: If you require a printed version of this wall chart please use the PDF version as the HTML version may not render correctly.
The PDF print version of this chart can be printed in A4 size or in large wall chart size (A3) by adjusting print options.
[Print-friendly PDF]
Recognise clinical features
  • sensations of warmth, itching especially in axillae and groins
  • feelings of anxiety or panic
  • erythematous or urticarial rash
  • oedema of face, neck, soft tissues
  • abdominal pain and vomiting
  • dyspnoea
  • hypotension (shock)
  • bronchospasm (wheezing)
  • laryngeal oedema (stridor, aphonia, drooling)
  • arrhythmias, cardiac arrest
  • hypoxaemia, cyanosis
Note: Severe clinical features may appear extremely rapidly without prodromal features
Acute management
Anaphylaxis is a life-threatening emergency
Use the ABC of resuscitation (Airway, Breathing and Circulation)
IF WORKING ALONE, CALL FOR ASSISTANCE
1
Remove allergen
Stop any suspected medication or diagnostic contrast material, remove allergen from patient's mouth, scrape out bee stings.
2
Give oxygen
Lie patient flat and give oxygen by face mask at the highest possible flow rate (> 6 L/minute).
3
Give adrenaline
Immediately inject adrenaline 1:1000 intramuscularly in the lateral thigh.
Adults (and children > 25 kg)

Children (< 25 kg)  
(use 1 mL/insulin syringe)
< 50 kg
give 0.25 to 0.50 mL

1 year
  10 kg
give 0.1 mL
> 50 kg
give 0.50 mL

3 years
  15 kg
give 0.15 mL
 


5 years
  20 kg
give 0.2 mL
(See Notes 1, 2)


8 years
  25 kg
give 0.25 mL
4
Start rapid fluid resuscitation
Establish an intravenous line and infuse normal saline or Hartmann's solution (20 mL/kg). Continue as necessary.
5
Give further adrenaline
If necessary, repeat intramuscular dose every 5 minutes. Large doses of adrenaline may be needed, up to a maximum of 5 mL (5 mg). If the patient remains shocked after two intramuscular doses, consider an adrenaline infusion to restore blood pressure. (See Notes 3, 4)
6
Ventilate
If there is severe respiratory and circulatory collapse or coma, ventilate the patient. (See Note 5)
7
Additional measures
Bronchodilators
For bronchospasm, give salbutamol or terbutaline by nebuliser, or aerosol with spacer device. In severe cases use continuously.
Corticosteroids
Give hydrocortisone 2 to 6 mg/kg or dexamethasone 0.1 to 0.4 mg/kg intravenously. (See Note 6)
Nebulised adrenaline (5 mL of 1:1000).
May be tried in laryngeal oedema and may ease upper airway obstruction. However, do not delay intubation if upper airway obstruction is progressive.
8
Supportive treatment
Observe vital signs frequently and, if possible, monitor electrocardiogram and pulse oximetry.
Keep patient in hospital for observation for at least 4 to 6 hours after the complete resolution of abnormal symptoms and signs, as biphasic reactions may occur. (See Note 7)
Notes
1.
Adrenaline is life-saving and must be used promptly. Withholding adrenaline due to misplaced concerns of possible adverse effects can result in deterioration and death of the patient. It is safe and effective.
2.
Adrenaline 1:1000 contains 1000 microgram in 1 mL (1 mg/mL). The volumes of adrenaline recommended for adults and children approximate to 5 to 10 microgram/kg. Children's weights are approximate for age.
3.
If critical care facilities are not immediately available, give the following adrenaline infusion:
• Mix 1 mg adrenaline (1 ampoule) in 1000 mL of normal saline
• Start infusion at 5 mL/kg/hour (approx. 0.1 microgram/kg/minute)
• Titrate rate up or down according to response.
4.
Some cases are resistant to adrenaline, especially if the patient is taking beta blocking drugs. If adequate doses of adrenaline are not improving the situation, give glucagon 1 to 2 mg intravenously over 5 minutes.
5.
Drug-assisted intubation for impending airway obstruction is a very high-risk procedure and should only be attempted by an expert.
6.
Corticosteroids may modify the overall duration of a reaction and may prevent relapse. However, onset of action will be delayed. Never use these to the exclusion of adrenaline.
7.
Keep patient in hospital longer if there is a history of asthma or previous allergy, or if the patient needed repeated doses of adrenaline. All patients must be followed up to investigate possible provoking factors and for further management.
Published as an insert to Australian Prescriber 2007, Vol.30 No.5 (http://www.australianprescriber.com/magazine/30/5/artid/913/).
Endorsed by the Australasian College for Emergency Medicine, the Australasian Society of Clinical Immunology and Allergy, the Australian and New Zealand College of Anaesthetists, the Royal Australasian College of Physicians (adult and paediatric divisions), and the Royal Australian and New Zealand College of Radiologists.

Emergency adrenaline infusion without an infusion pump for life-threatening anaphylaxis-induced hypotension in an adult or adolescent (Box 14.13)
By Piscean | | Posted in , , , | With 0 comments

Emergency adrenaline infusion without an infusion pump for life-threatening anaphylaxis-induced hypotension in an adult or adolescent (Box 14.13)
If an adult or adolescent with anaphylactic shock remains hypotensive despite IM adrenaline and fluid resuscitation (20 mL/kg normal saline run through as rapidly as possible under pressure), then an intravenous infusion of adrenaline, even without an infusion pump, is warranted [NB1] [NB2].
This is a temporary measure until emergency medical services arrive or the patient can be moved to a critical care area. Use it only for severe cases where death is considered likely without intervention.
In this situation, through another peripheral intravenous line, use:
adrenaline 1 mg in 100 mL sodium chloride 0.9% IV, at approximately 100 mL/hour, which is one drop every 2 seconds for most standard drip sets [NB3].
If you only have a 500 mL or 1000 mL bag of infusion fluid [NB2], use:
adrenaline 1 mg in 500 mL sodium chloride 0.9% IV, at approximately 500 mL/ hour, which is 2 drops per second for most standard drip sets
OR
adrenaline 1 mg in 1000 mL sodium chloride 0.9% IV, at approximately 1000 mL/hour, which is 5 drops per second for most standard drip sets.
Titrate carefully, monitoring systolic blood pressure every few minutes using the 'palpation' method, see Assessment of blood pressure in anaphylaxis. Reduce the rate immediately if signs of adrenaline toxicity (tachycardia, tremor and pallor in association with a normal or raised blood pressure) develop. If toxicity is severe, stop the infusion briefly before recommencing at a lower rate.
See Table 14.15 for further advice regarding adjustment, de-escalation and cessation of the adrenaline infusion.
NB1: Children with severe/persistent anaphylaxis usually have a bronchospastic reaction rather than a hypotensive one. Absorption from the intramuscular site will be good; therefore, use a second intramuscular dose rather than an infusion (see Children with life-threatening anaphylaxis).
NB2: Adrenaline is compatible with most standard infusion solutions. Normal saline (sodium chloride 0.9%) is preferred in anaphylaxis, but if supplies are being used for simultaneous fluid resuscitation, use glucose 5% or any other standard infusion fluid for the adrenaline infusion.
NB3: For most standard drip sets 1 mL = 20 drops. Therefore for a 100 mL bag, you will be giving 20 x 100 = 2000 drops per hour, or approximately 30 drops per minute, ie one drop every 2 seconds. For a 500 mL bag, it will be 5 times this rate (150 drops per minute or approximately 2 drops every second) and for a 1000 mL bag, it will be 300 drops per minute or 5 drops per second.
Table (adapted with permission from Brown SG. Anaphylaxis: clinical concepts and research priorities. Emergency Medicine Australasia 2006; 18(2):155-69. © 2006 Wiley-Blackwell Publishing Ltd.)
Emergency management of anaphylaxis (Table 14.14)
By Piscean | | Posted in , , , | With 0 comments

Emergency management of anaphylaxis (Table 14.14)
1
Stop administration of any precipitant, assess severity of reaction (see Table 14.13) and treat accordingly.
Call for assistance.
Give intramuscular adrenaline (adult or child):
adrenaline 0.01 mg/kg up to a maximum of 0.5 mg (= 0.5 mL of 1:1000 solution) IM (lateral thigh).
Establish IV access.
Lie patient flat.
Give high flow oxygen, airway/ventilation support if needed.
If hypotensive, establish additional wide bore access (ie 14G or 16G in adults) for normal saline infusion. Use:
sodium chloride 0.9% solution 20 mL/kg IV bolus, over 1 to 2 minutes under pressure.
2
If there is an inadequate response, an immediate threat to life or deterioration:
Start an IV adrenaline infusion, see Table 14.15
OR
Repeat IM adrenaline every 3 to 5 minutes as determined by BP and bronchospasm.
Consider also:
For hypotension,
repeat normal saline boluses:
sodium chloride 0.9% solution 10 to 20 mL/kg IV bolus, up to total of 50 mL/kg over the first 30 minutes.
treat severe bradycardia if present:
atropine 0.02 mg/kg IV. [NB1]
vasopressors to overcome vasodilatation (adult doses) [NB2] [NB3]:
vasopressin 10 to 40 units IV
OR
metaraminol 2 to 10 mg IV.
for anaphylactic cardiac arrest, rapid escalation to high-dose adrenaline (3 to 5 mg IV every 2 to 3 minutes in adults) may be effective.
if beta blocked or in heart failure (adults), consider glucagon/phosphodiesterase inhibitors/balloon pump, eg:
glucagon 1 to 5 mg IV loading dose over 5 minutes, followed by 5 to 15 micrograms/minute.
For bronchospasm,
continuous salbutamol nebulisers (5 mg by nebuliser driven by oxygen at least 8 L/minute), or continuous actuations of metered dose inhaler into ventilation circuit if intubated
corticosteroids:
hydrocortisone 5 mg/kg IV 6 hourly
FOLLOWED BY
prednis(ol)one 1 mg/kg up to a maximum of 50 mg orally daily for 4 days.
For upper airway obstruction,
nebulised adrenaline may provide some relief, use:
adrenaline 5 mg in 5 mL (= 5 mL of 1:1000 solution) via nebuliser
prepare for surgical airway.
3
Observe for an adequate period and arrange appropriate follow-up.
Inpatient care
After the resolution of all symptoms and signs, observe for a minimum of 4 hours after the last dose of adrenaline or until daylight hours. Children or adults with a likelihood of biphasic reaction should be admitted for at least 12 hours.
Take blood for mast cell tryptase on arrival, 1 hour after arrival, and prior to discharge. Admit longer (overnight) those with severe reactions, a history of life-threatening reactions or poorly controlled asthma, and those who present late in the evening.
Prior to discharge
Discuss allergen avoidance measures (including wearable personal medical identification, eg MedicAlert).
Ensure that an alert is placed in hospital/practice records/computer system.
Ensure that referral letter/summary contains a detailed record of reaction features and timing, possible precipitants and times of exposure.
Outpatient follow-up
Follow-up by a specialist allergist is recommended for all those with moderate to severe reactions, and with mild reactions to food if the patient also has asthma. If there is significant risk of re-exposure prior to allergist follow-up:
Arrange for an EpiPen [NB4].
Demonstrate correct use with an EpiPen trainer.
Provide a written action plan (www.allergy.org.au).
NB1: If required in a child, minimum total dose should be atropine 0.1 mg IV, as lower doses have been reported to cause paradoxical bradycardia in children.
NB2: In children, hypotensive anaphylaxis is very rare with inadequate experience to provide dosage recommendations.
NB3: It is important to note that in anaphylaxis the BP is not just low, but may be unrecordable. Therefore doses of vasoconstrictors are much higher than those used in other clinical situations where hypotension may imply a BP of 90 mm Hg or less.
NB4: EpiPen is the Australian trade name of a pre-loaded auto-injector pen containing adrenaline 300 micrograms in 0.3 mL. EpiPen Jr contains adrenaline 150 micrograms in 0.3 mL.
Adapted with permission from Brown SG. Anaphylaxis: clinical concepts and research priorities. Emergency Medicine Australasia 2006; 18(2):155-69. Copyright © 2006 Wiley-Blackwell Publishing Ltd.