• 
• 

Three Part Question

In [asthmatic patients who need RSI and ventilation] does [pre-treatment with intravenous lignocaine prior to RSI] reduce the incidence of [adverse airway responses]?

Clinical Scenario

A patient attends the emergency department in status asthmaticus. On examination they have a sinus tachycardia at a rate of 150/min, an oxygen saturation of 92% on high flow oxygen and a pCO2 of 7.0kPa. Despite maximal medical treatment they are becoming exhausted. You decide that the patient needs a rapid sequence intubation and continuous mandatory ventilation. You wonder whether the pretreatment with lignocaine will attenuate the respiratory response (bronchospasm) to airway manipulation.

Search Strategy

Medline OVID 1966-week 4 June 2005
Embase OVID 1980-week 27 2005.
The Cochrane library Issue 2 2005.
Medline: [exp Asthma OR exp Asthma, exercise induced OR asthma$.mp OR exp Bronchial spasm OR bronchospasm.mp] AND [exp Lidocaine OR lidocaine$ OR lignocaine$ OR lignocaine.mp] LIMIT to human, English language and publication year 2000-2005
Embase OVID 1980-week 27 2005. [exp Asthma OR exp Asthma, exercise induced OR asthma$.mp OR exp bronchospasm OR bronchospasm.mp] AND [exp Lidocaine OR lidocaine$ OR lignocaine$ OR lignocaine.mp] LIMIT to human, English language and publication year 2000-2005
The Cochrane library Issue 2 2005. [{Asthma MeSH }] AND [{bronchial spasm MeSH}] AND [{lidocaine MeSH OR lignocaine ALL FIELDS}]

Search Outcome

157 papers were found 2000-2005 of which 143 were unique of which 1 was relevant to the question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Maslow AD et al, 2000, USA	60 asthmatic patients undergoing intubation. 1.5 mg/kg lidocaine vs saline given 3 min before tracheal intubation	PRCT	Lower pulmonary resistance	8.2 vs 7.6 cm water (ns)
			Frequency of airway response to intubation	6 of 30 vs 5 of 27 (ns)

Comment(s)

Tracheal intubation in asthmatics is linked to the risk of life-threatening bronchospasm. This reflex is in part neurally mediated via the vagus nerve. Local anaesthetics have been used as a pre-treatment to airway stimulation in susceptible patients in the hope of attenuating the reflex induced bronchoconstriction. The National Emergency Airway Course recommends a pre-treatment dose of IV Lignocaine (3mg/kg) given 3 minutes prior to intubation in this patient group. There is no evidence form the above trial that this will be of value. Interestingly pretreatment with albuterol did attenuate the response

Clinical Bottom Line

There is no evidence for the use of Lignocaine as a pre-treatment agent in asthmatic patients needing an RSI.

References

1. Maslow AD, Regan MM, Israel E et al. Inhaled albuterol, but not intravenous lidocaine, protects against intubation-induced bronchoconstriction in asthma. Anesthesiol 2000;93:1198-204.