Br. J. Anauth. (1983), 55, 49
INTRANASAL ADMINISTRATION OF NITROGLYCERINE ATTENUATES THE PRESSOR RESPONSE TO LARYNGOSCOPY AND INTUBATION OF THE TRACHEA A. FASSOULAKI AND P. KANIARIS SUMMARY
Cardiovascular instability, as demonstrated by increases in arterial pressure and heart rate (HR), accompanies direct laryngoscopy and tracheal intubation (Wycoff, 1960; Prys-Roberts et al., 1971; Stoelting, 1977). Usually these transient changes have no deleterious consequences, but in some patients they can provoke left ventricular failure (Masson, 1964), myocardial ischaemia and cerebral haemorrhage (Forbes and Dally, 1970). The present study assessed the efficacy of nitroglycerine (NTG) solution administered intranasally before laryngoscopy and intubation in the prevention of these changes. PATIENTS AND METHODS Sixty-seven female patients (ASA class I) aged between 21 and 36 yr and undergoing excision of a breast lump were studied (weight range 61-77 kg). All gave informed consent to participate in the study. All patients had normal electrocardiograms (ECG) on admission to the hospital and arterial pressures within the physiological range. Premedication consisted of diazepam 20 mg by mouth 90min before the induction of anaesthesia. No anticholincrgic drugs were given. On arrival of A. FASSOULAKI,* M.D., St Savas Hospital, Athens 603 and Department of Pharmacology, University of Athens; P. KANIARIS, M.D., PH.D., Department of Pharmacology, Division of Anaesthesia, Medical School, University of Athens, Goudi 609. •Address for correspondence; 57-59 Raftopoulou Street, Athens 405/1, Greece. The authors regret that no reprints will be available. 0007-0912/83/010049-04 $01.00
the patient in the operating theatre, systolic arterial pressure (SAP) and HR were recorded after a resting period of 5 min. No invasive methods were used to record SAP and HR as the operation performed was minor and did not justify their use. The 67 patients were randomly allocated to two groups: an NTG group and a control group. After 5 min oxygenation with 100% oxygen via a mask, 35 patients received 2 ml of an NTG solution (60 mg) which was instilled intranasally using a glass syringe and a 16-gauge teflon i. v. cannula. The dose of NTG was arbitrarily chosen (15mg for each 20 kg of the patient's weight). As the body weight of the patients varied between 61 and 77 kg, each received 60 mg of NTG (2 ml solution). One minute after the nasal administration of NTG, anaesthesia was induced with thiopentone 6 mgkg" 1 followed by suxamethonium 1.5mgkg"' to facilitate endotracheal intubation. Each intubation of the trachea was performed by the first author. When difficulties in intubation occurred or if intubation was not accomplished at the first attempt the patient was withdrawn from the study. SAP and HR were recorded as soon as the cuff of the tracheal tube was inflated (time zero) and at 3 and 5 min after intubation in the absence of concurrent stimulation produced by surgery. The remaining 32 patients (control group) did not receive NTG. Following tracheal intubation, ventilation of the lungs was controlled with 33% oxygen in nitrous oxide for 5 min. No analgesic drugs or inhalation anaesthetics which might have affected the hypotensive effect of NTG were given for the 5 min following tracheal intubation. © The Macmillan Press Ltd 1983
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The intranasal administration of nitroglycerine (NTG) was undertaken in 35 adult female patients before the induction of anaesthesia. A control group consisting of 32 patients did not receive NTG. Systolic arterial pressure (SAP) and heart rate (HR) were recorded before the induction of anaesthesia and at 0,3, and 5 min after tracheal intubation. SAP did not increase significantly in the NTG group immediately after intubation, while significant decreases in SAP were observed at 3 and 5min ( P < 0.005 and P < 0.001 respectively). SAP did increase significantly in the control group. HR was increased in both groups immediately after intubation (i>< 0.001 and P< 0.001 respectively). NTG administered intranasalry is a safe, simple and effective method to attenuate the hypertensive response to laryngoscopy and tracheal intubation.
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Student's rtest for paired observations was used for analyses within the groups, and that for unpaired observations for analyses between groups.
TABLE I. Mean systolic arterh.1 pressures (mm Hg) (± SEM) before induction of antusthtsia, and at 0, 3 and 5 min after tracheal intubation. Statistically significant differences; *on analysis within tht groups; ton analysis between groups (NTG v. control group)
RESULTS
Systolic arterial pressure
Heart rate
HR was significantly increased in both groups after intubation ( P < 0.001 and P< 0.001 respectively). At 5 min after intubation HR was still faster in the NTG group while in the control group it had declined to the values obtained before induction of anaesthesia (table III). DISCUSSION NTG is rapidly absorbed into the vascular space when administered intranasally. The peak blood concentrations are reached at 2 min and decrease rapidly within 15min (Hill et al., 1981). In their study, Hill and colleagues (1981) claimed that neither systemic hypotension nor tachycardia occurred following the administration of the drug by this route. However, doses used were smaller than those of the present study. Since the hypertensive response to laryngoscopy and intubation is observed after 15 s (Stocking, 1977), the intranasal administration of NTG 1 min before the start of the injection of thiopentone should produce peak concentrations coincident with the increase in arterial pressure which accompanies laryngoscopy and intubation. An allowance of 30-45 s was made to cover the times required to inject the thiopentone and suxamethonium and undertake laryngoscopy. No significant increases in SAP were observed, after laryngoscopy and tracheal intubation, in those patients who received intranasal NTG whereas SAP
0 min
3 min
5 min
NTG(» = 35) Mean SEM
143.7 4.14
150.6t 4.14
131.4*t 4.2
122.6* 3.3
Control (« - 3 2 ) Mean SEM
136 3.06
182* 5.25
146 4.64
129 3.42
Group
TABLE II. Number of patients in each group who had increases in systolic arterial prtssurt > 10mmHg, >20mmHg, >30mmHg and > 40 mm Hg following intubation Increase in SAP Group
>10mmHg >20mmHg >30mmHg >40mmHg
NTG
10
2
Control
2
7
4
17
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In patients who received NTG, SAP did not change significantly as a result of tracheal intubation. A statistically, but not clinically significant, decrease in SAP was observed at 3 and 5 min after intubation (P<0.05 and P< 0.001 respectively) (table I). An abrupt increase in SAP was observed in the control group immediately after intubation (from a mean value of 136 mm Hg to a mean value of 182mmHg) ( P < 0.001). SAP was significantly greater at 0 and 3 min after intubation in the control group when compared with the NTG group (table I) and the range of increases in SAP following intubation was greater in the patients in the control group (table II). SAP did not differ between the groups following operation.
After intubation Before induction
TABLE HI. Mean heart rates (± SEM) (beat min-') before induction of anaesthtsia and at 0, 3, and 5 min after tracheal intubation. "Statistically significant difference on analysis within groups; tstatistically significant differenct on analysis between groups (NTG v. control group) After intubation Before induction
Omin
3 min
5 min
NTG ( n - 3 5 ) Mean SEM
89 1.85
102* 2.58
97* 2.42
96t* 2.39
Control ( n - 3 2 ) Mean SEM
89 2.47
106* 2.42
95 2.34
88 2.36
Group
was significantly increased in the other patients. HR was significantly increased in both groups of patients after intubation and no significant differences were detected either before anaesthesia or on intubation between the groups. The significantly faster HR observed in the NTG group at 5 min after intubation cannot be considered clinically significant, particularly since atropine had not been administered (Fassoulaki and Kaniaris, 1982). The method used has been proved effective, safe, rapid, convenient and economical. The administra-
NITROGLYCERINE AND THE PRESSOR RESPONSE TO INTUBATION
REFERENCES
Cossum, P.A., Galbraith, A.J., Roberts, M.S., and Boyd, G.W. (1978). Loss of nitroglycerin from intravenous infusion sets. Lancet, 2,349. Fassoulaki, A., and Kaniaris, P. (1982). Does atropine premedication affect the cardiovascular response to laryngoscopy and intubation? Br. J. Anauth., 54, 1065. Forbes, A.M., and Dally, F.G. (1970). Acute hypertension during induction of anaesthesia and endotracheal intubation in normotemive man. Br. J. Anaesth., 42,618. Hill, A. B., Bowley, C. J., Nahrwold, M. L., Knight, P. R., Kirsh, M. M., and Denlinger, J. K. (1981). Intranasal administration of nitroglycerin. Atusthesiology, 54, 346. Masson, A. H. B. (1964). Pulmonary nirmf during or after surgery. Antsth. Analg., 43,440. Prys-Robem, C , Greene, L. T., Meloche, R., and Foex, P. (1971). Studies of anamthmin in relation to hypertension. II: Haemodynamic consequences of induction and endotracheal intubation. Br. J. Anaath.,43, 531.
Stoelting, R. K. (1977). Circulatory changes during direct laryngoscopy and tracheal intubation: influence of duration of laryngoscopy with or without prior lidocaine. Anathesiology, 47,381. , (1979). Attenuation of blood pressure response to laryngoscopy and intubation with sodium nitropniiside. Anesth. Ward, J. W., Sandier, A. I., and Tucker, S. V. (1979). Nitroglycerine for i.v. infusion. Druglntell. Clin. PtiarmacoL,Yi, 14. Wycoff, C. O. (1960). Endotracheal intubation: effects on blood pressure and pulse rate. Amukesiology, 21, 153.
L'ADMINISTRATION PAR VOIE NASALE DE NITROGLYCERINE DIMINUE LA REPONSE TENSIONNELLE A LA LARYNGOSCOPIE ET A LTNTUBATION TRACHEALE RESUME
L'administration par voie nasale de nitroglycerine (NTG) a etc utilisec chez 35 femmes adultes 1 min avant l'induction de l'anesthesie. Un groupe contrdle de 32 patients n'a pas recu de NTG. La pression arterielle systolique (PAS) et la frequence cardiaque (FC) ont ete mesurees avant l'induction de l'ancsthesie et a 0,3 et 5 min apres l'intubation tracheale. La PAS n'a pas augmente de facon significative dans le groupe NTG juste apres l'intubation alors que des diminutions significatives de PAS ont ete observees a 3 et 5min ( P < 0,005 et P < 0.001 respectivement). La PAS a augmente de facon significative dans le groupe contr&le. La FC a augmente dans les deux groupes juste apres l'intubation ( P < 0,001 et P< 0,001 respectivement). La NTG administree par voie nasale est une methode sure, simple et cfficace pour attenuer la reponse hypertensive a la laryngoscopie et a l'intubation tracheale.
INTRANASALE VERABREICHUNG VON NITROGLYCERIN SCHWACHT DEN BLUTDRUCKANSTIEG NACH LARYNGOSKOPIE UND TRACHEALER INTUBATION AB ZUSAMMENFASSUNG
Nitroglycerin (NTG) wurde 35 erwachsenen Paucntinnen eine Minute vor der Narkoseeinleitung intranasal verabreicht. Eine Kontrollgruppe, die aus 32 Patientinnen bestand, erhielt kein NTG. Der systolische arterielle Druck (SAP) und die Herzfrequcnz (HR) wurden vor der Narkoseeinleitung und 0,3 und 5 Minuten nach der trachealen Intubation aufgezeichnet. Der SAP stieg in der NTG-Gruppe unmittelbar nach der Intubation nicht signifikant an, wShrend signifikante AbfiQle des SAP nach 3 und 5 Minuten zu beobachten waren (P<0,005 und P<0,001 in der genannten Reihenfolge), wahrend SAP in der Kontrollgruppe sofort aignifiknnt nn«tifg Die HR war in beiden Gruppen unmittelbar nach der Intubation (P<0,001 und P<0,001 in obiger Reihenfolge) erhoht. NTG intranasal verabreicht ist ein sicheres, einfaches und wirksames Mittel um den Blutdruckanstieg nach Laryngoskopie und trachealer Intubation abzuschwachen.
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tion of solutions of NTG i.v. using non-absorbent infusion sets is more expensive, while loss of the drug from the ordinary infusion sets is an additional problem (Cossum et al., 1978; Ward, Sandier and Tucker, 1979). In contrast a solution of NTG for intranasal administration can be prepared readily by the anaesthetist crushing NTG tablets in normal saline just before the induction of anaesthesia. The principal advantage of the method described is that, while a desirable and transient hypotension is achieved, cardiac output is not likely to decrease to the same degree as with other hypotensive agents. Sodium nitroprusside has been used to attenuate the hypertensive response to laryngoscopy and intubation (Stoelting, 1979). However, the action of this drug on the coronary vessels has not been assessed. By dilating the coronary vessels just before the commencement of anaesthesia, NTG may increase coronary blood flow and oxygen delivery to the myocardium. Thus hypertension during tracheal intubation is avoided and, at the same time, the technique may be of benefit to patients with ischaemic heart disease and impaired myocardial function. However, it must be emphasized the the present study was based on healthy subjects and the data can not be extrapolated to hypertensive patients with myocardial ischaemia. Modifications of the dose of NTG used in the present study may be required. In conclusion, the present study establishes the usefulness of the nasal administration of NTG to attenuate the hypertensive response to laryngoscopy and tracheal intubation.
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52 ADMINISTRACI6N INTRANASAL DE NITROGLICERINA ATENUA LA RESPUESTA DEL PRESOR A LA LARINGOSCOPIA E INTUBACI6N DE LA TRAQUEA SUMARIO
Sc llevo a cabo una administracion intranasal de nitroglicerina (NTG) a 35 pacientes mujeres adultas 1 min antes de la induccion de la anestesia. Un grupo de control de 32 pacientes no recibi6 NTG. Se tom6 registros de la presi6n arterial sistolica (SAP) y del
ritmo cardiaco (HR) antes de la induccion de anestesia y a los 0,3 y 5 min despues de la intubacion traqueal. La SAP no aumcnt6 de mancra significante en el grupo con NTG inmediatamente despues de la intubaci6n, mientras se observaron descensot lignificativos de la SAP a los 3 y 5min ( P < 0 , 0 0 5 y P < 0 , 0 0 1 , respectivamente). La SAP aumento de manera significante en el grupo de control. El HR aumento en ambos grupos inmediatamente despues de la intubacidn (P<0,001 y P < 0 , 0 0 1 , respectivamente). La administracion intranasal de NTG constituye un metodo seguro, sencillo y eficaz de atenuar la respuesta hipenensiva a la laringoscopia y a la intubacidn traqueal.
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