Intranasal nitroglycerine attenuates pressor response to tracheal intubation in beta‐blocker treated hypertensive patients

Abstract

Key wordsAnu (,v[iit,tir t~c h n i y u~.~: tracheal intubation Phurmucolugy: nitroglycerine.Tachycardia and hypertension are well-documented reflex cardiovascular effects of laryngoscopy and tracheal intubation in normotensive subjects.' The extent of these reflexes is more marked in both treated and untreated hypertensive patients.2 Intranasal nitroglycerine has been shown to attenuate the pressor response to laryngoscopy and intubation in normotensive p a t~e n t s .~ Its use in hypertensive patients has not heen reported so far. The present study was undertaken to assess the effect of nitroglyccrine solution administered intranasally before laryngoscopy, to prevent the cardiovascular changes associated with laryngoscopy and tracheal intubation..Mii/ericd utid n7efhotl.sThe study was carried out in a double-blind manner. Forty, mild to moderately hypertensive patients (pretreatment diastolic arterial pressure 10G130 mmHg) rccciving therapy in the form of beta-blocking drugs alone. or in addition to a diuretic, were selected.Patients with obstructive lung disease. a history of angina or previous myocardial infarction. congestive cardiac failure or 2nd and 3rd degree AV block, were excluded from the study. All the patients were scheduled for short surgical procedures.The day before surgery, the purpose of the atudy and the proccdurc to bc undertaken were explained to the patients and informed consent was obtained. The antihypertensive medication was continued until the morning of surgery. All the patients were placed first on the operation list. so that the interval between the morning dose of antihypertensivc medication and induction of anaesthesia was about 2 hours. Premedication was with morphine 0.1 mg:kg and protnethazine 0.4 mgjkg intramuscularly. one hour before anaesthesia. Patients were allocated to one of two groups (20 in each group) with the help of a randomisation chart.The arterial blood pressure was measured after a resting period of 10 minutes, subsequent to arrival of Forum 885 the patient in the operating theatre. Basal heart rate readings were recorded after a continuous display of heart rate and ECG had been established on an oscilloscope using ECG leads in the CMS position. Depending upon the allocation of paticnts to a particular group, they received either 1.5 ml normal saline (group I ) or 1.5 ml nitroglycerine solution (group 2). The nitroglycerine solution was prepared by dissolving two crushed tablets of 0.5 mg each in 2 ml saline, by a worker who was not associated with the monitoring of blood pressure and heart rate. The same worker loaded I .5 ml of saline or nitroglyccrinc solution in a 5-ml syringe (taped to prevent recognition on the basis ofcolour) and instilled i t intranasally with an opaque intravenous cannula (Angiocath).Anaesthesia was induced 30 seconds after the administration of the solution, with a sleep dose of sodium thiopentone 4 6 mg/kg followed by suxamethonium 1.5 mg/kg. The induction drugs were administered within 40 -50 seconds. Laryngoscopy and tracheal intuba...

Attenuation of pressor response following intubation: Efficacy of nitro-glycerine lingual spray

“…Previous studies[ 11 17 18 19 20 ] have also documented that NTG does not attenuate the rise in HR after intubation which can be attributed to reflex tachycardia produced by vasodilation.…”

Attenuation of stress response to laryngoscopy and intubation: sublingual nitroglycerin spray vs intravenous fentanyl and sublingual nitroglycerin spray

“…NTG had been administered in different doses and through different approaches like intranasal, topically or parenterally as a bolus or infusion to attenuate hemodynamic responses during laryngoscopy and intubation. 19 Kumari I et al used sublingual Nitroglycerin in two doses (0.4mg and 0.8mg) Kamra S et al used 2% topical Nitroglycerin ointment equivalent to 30 mg Nitroglycerin. 13,14 Fassoulaki A and Kaniaris P used Nitroglycerin intranasally in a dose of 60 mg. 15 Anant and Waghray used intranasal NTG spray for attenuation of pressor response to intubation.…”

“…also found similar results coinciding our study. 13,14,17,19,23 Fusciardi J et al concluded that addition of Nitroglycerin by infusion to low-dose Fentanyl anesthesia produced no significant change in MPB, heart rate, cardiac index, or PCWP and is an attractive method for induction as well as decreasing the incidence of myocardial ischemia associated with laryngoscopy and intubation in patients with stable angina undergoing short-duration noncardiac surgery.…”

“…13 Studies conducted by Mikawa K et al, Grover VK et al and Fassoulaki A and Kaniaris P have also documented that NTG does not attenuate the rise in heart rate following laryngoscopy and endotracheal intubation which can be attributed to reflex tachycardia produced by vasodilatation. 15,18,19 When intravenous Fentanyl was used along with Nitroglycerin sublingual spray in group 3 (F+NTG), it resulted in more optimal control of tachycardia produced by laryngoscopy and intubation. In the group 3, baseline heart rate came down just before intubation and then rose to maximum at 1 minute after intubation followed by gradual fall at 3 rd and 5 th minutes bellow the baseline value.…”

Emergency management of the airway outside the operating room

“…Nitroglycerine (NTG) is effective when administered nasally in a dose of 0.75 mg and given 60 sec CANADIAN JOURNAL OF ANAESTHESIA before intubation. 163 The safety of this route of administration is apparent from a similar study which showed efficacy without side effects and involved the use of a dose of 60 mg of NTG, fully 80 times larger than the former study's dose. 164 Prophylactic infusions of NTG in cardiac surgical patients have been shown to decrease hypertensive responses to intubation, its The effectiveness of NTG has been questioned when given intravenously in noncardiac patients.…”