The effects of endotracheal intubation and laryngeal mask airway on the risk of myocardial ischemia in cardiac patients

THE EFFECTS OF ENDOTRACHEAL IN TU B A TIO N A N D

LAR YN G EAL M A S K AIR W AY O N THE RISK OF M YO CAR DIAL

ISCHEMIA IN CARDIAC PATIENTS

Binnaz A y , M .D .*/ Zeynep Eti, M.D.* / A . Serdar Fak, M.D.**

Tüm ay Um uroğlu, M.D.* / F. Yılm az Göğüş, M.D.*

* D e p a rtm e n t o f A n e s th e s io lo g y a n d R e a n im a tio n , S c h o o l o f M e d ic in e , M a rm a ra U n iv e rs ity , İs ta n b u l, Turkey. ’ ’ D e p a rtm e n t o f C a rd io lo g y , S c h o o l o f M e d ic in e , M a rm a ra U n iv e rs ity , İs ta n b u l, Turkey.

ABSTRACT

Objective:

Methods:

patients. In group I the patients were intubated, in group II LMA was inserted for maintenance of airway. Mean arterial pressure (MAP), heart rate (HR), rate pressure product (RPP), and ST segmet changes were recorded. Postoperatively 12 lead electrocardiography and CPK, CPK-MB levels were also recorded.

Results:

times in 3 patients in group II.

Conclusion:

K e y

W o rd s :

endotracheal intubation, myocardial ischemia

INTRODUCTION

Perioperative cardiac morbidity is the leading cause of death dung aneshesia and postoperative period (1).

Hypertension is the most common cardiovascular disease however coronary artery disease (CAD) has the highest morbidity and mortality. Perioperative myocardial ischemia is verified by electrocardiography (ECG), cardiocymography and transesophageal echocardiography in 18-74 % patients who have CAD, undergoing non-cardiac surgery (1-4). Tachycardia, hypertension, anemia, stress, use of sympathomimetic drugs which increase myocardial oxygen demand can lead to myocardial ischemia (1,5,6).

The stress response characterized by sympathetic activation is one of the most serious side effects of endotracheal intubation (7). Although a variety of pharmacological agents are used in order to prevent this hemodynamic response, none of the agents or techniques are totally effective. Hypertension and tachycardia caused by the stress response will put impact on patients whose myocardial perfusion is not adequate and may lead to perioperative myocardial ischemia.

The aim of this study was to compare the hemodynamic and ST segment changes caused by endotracheal intubation and laryngeal mask airway (LMA) insertion and to assess the relation of these changes with myocardial ischemia in patients with CAD and/or congestive heart failure (CHF).

( A c c e p t e d 11 N o v e m b e r , 1 9 9 9 ) M a r m a r a M e d ic a l J o u r n a l 2 0 0 0 ; 1 3 (1 ) : 1 5 - 1 8 15

B in n a z A y , e t a t

MATERIALS A N D M ETHODS

After Faculty Ethics Committee approval and patients' written consent, 30 patients having CAD and/or CHF, ASA lll-IV, aged between 60-80 years, scheduled for elective peripheral surgery such as orthopaedic, opthalmologic, urologic and ear-nose-throat surgery were included Into the study protocol. Diagnosis of CAD was made in the presence of a diagnostic coronary angiography or a documented history of myocardial infarction or a positive stress test. Diagnosis of CHF was made in the presence of abnormal ejection fraction, low cardiac output, Increased left ventricular pressure and left ventricular wall motion abnormalities.

12 lead ECG and echocardiography were obtained and blood samples were collected for CPK, CPK-MB levels preoperatively. Patients were evaluated by Goldman and Detsky Cardiac Risk Index (6) and

assigned into two groups (n=15) equally according to the risk assessment and ejection fraction. All patients were premedicated with 50 mg pethidine i.m. 1 hour before surgery. Dll, V5 derivations and heart rate (HR) with 5-lead ECG, systolic, diastolic and mean arterial pressure (MAP) with radial artery catheter were monltorlzed continuously.

After anesthesia induction with 0.2 mg/kg etomidate, 15 pg/kg alfentanil and 0 .1 mg/kg vecuronium i.v., the

patients were assigned into two groups (n=15). In group I, the patients were intubated endotracheally and in group II LMA was inserted. Anesthesia was maintained with 1 MAC isoflurane and 50 % N20 in oxygen.

Systolic, diastolic, MAP, HR were recorded and rate pressure products (RPP) were calculated before induction (T1), after induction (1 2 ), during intubation or LMA insertion (T3), 1,3 and 5 minutes after airway manipulation (T4,T5,T6).

1 mm or greater ST segment depression or 2 mm or greater.ST segment elevation compared to the control value for more than 1 minute was considered as

intraoperative myocardial ischemia (8,9).

12 lead ECG, serum CPK, CPK-MB values were evaluated 6 and 24 hours postoperatively. CPK-

MB>25 IU/L was considered as a sign of myocardial ischemia.

Results were analysed statistically with ANOVA for repeated measurements, Tukey-Kramer and Fisher's exact test and a p<0.05 was considered as statistically significant.

RESULTS

There was no difference in demographic data, duration of surgery, Goldman and Detsky Cardiac Risk Index scores of patients (Table I).

Preoperative ECG data and ejection fractions of patients were shown in Table II and III.

There was no difference in MAP before induction between groups. In group I; MAP increased significantly during intubation and after 1 min

compared with control value (p<0.05) while in group II; there was no increase during intubation and MAP decreased significantly at 3th and 5th min of intubation (p<0.05). MAP of group II was significantly lower than that of group I at 3rd min of intubation (p<0.05) Table IV) .

There was no difference in HR between groups. In group I; there was no difference in HR compared to control value however in group II; HR decreased significantly compared to control value (p<0.05) (Table

V) .

While RPP Increased significantly 1 min after intubation in group I, there was a significant decrease in RPP after Induction and 3 and 5 min after LMA insertion in group II (p<0.05). RPP of group II was significantly lower than that of group I at 3 min after airway manipulation (Table VI).

ST-segment changes indicating ischemia were recorded 15 times in 6 patients in group I and 4 times

in 3 patients in group II and the difference was significant (p<0.05). CPK-MB values were greater than 25 IU/L in 3 patients who had ST-segment changes in group I.

T a b l e I. D e m ographic data, d uration of su rg e ry and risk a sse ssm e n t scores (M ean±S D )

T R A C H E A L T U B E L M A (n = 1 5 ) (n = 1 5 )

Age (year) 70.00 ± 5.69 66.90 ± 6.22

Weight (kg) 73.40 ± 13.11 72.15 ± 9.45

Gender (M/F) 10/5 9/6

Duration of surgery (min) 91.00 ± 18.3 89.20 ± 16.5

Goldman Cardiac Risk Index 3.46 ± 4.17 4.31 ± 4.5

Detsky Cardiac Risk Index 6.60 ± 3 .61 9.00 ± 7.8

E n d o t r a c h e a l i n t u b a t i o n a n d L M A in c a r d i a c p a t i e n t s

T a b l e II. Preoperative electrocardiographic data of patients (%)

T R A C H E A L T U B E L M A ( n = 1 5 ) (n = 1 5 )

Normal ECG 6 (40%) 6 (40%)

Inferior Ml 4 (27%) 5 (33%)

A nterolateral Ml 2 (13%) 0

Left ventricular hypertrophy 6 (40%) 6 (40%)

T a b l e III. Ejection fraction values of patients (%)

E je c t io n f r a c t io n T R A C H E A L T U B E (n = 1 5 ) L M A (n = 1 5 ) Normal 7 (47%) 6 (40%) 55-40 % 7 (47%) 5 (33%) 35-25 % 1 (6%) 4 (27%) <25 % 0 0

T a b l e IV . Mean arterial pressure (mm Hg) (Mean±SD)

T R A C H E A L T U B E L M A ( n = 1 5 ) (n = 1 5 ) T 1 106.0 ± 15.3 110.5 ± 12.5 T2 104.0 ± 15.4 97.92 ± 13.7* T3 121.0 ± 23.3* 115.1 ± 9.82 T4 125.2 ± 23.6* 110.0 ± 14.4 T5 116.0 ± 22.5# 94.00 ± 12.9* T6 108.1 ± 29.0 89.92 ± 19.6

' p<0.05 in group com pared with T 1 # p<0.05 between groups T1 = Before induction

T2 = After induction

T3 = During intubation or LMA insertion T4 = 1 min after airw ay m anipulation T 5 = 3 m in after airw ay m anipulation T6 = 5 m in after airw ay m anipulation

T a b l e V . Heart rate (beat/m in) (Mean+SD)

T R A C H E A L T U B E (n = 1 5 ) L M A (n = 1 5 ) T 1 84.0 ± 12.2 92.0 ± 17.2 T2 74.9 ± 13.7 78.2 ± 19.0* T3 89.4 ± 16.1 81.6 ± 22.4* T4 91.1 ± 20.2 82.3 ± 24.5* T5 87.6 ± 23.7 75.1 ± 23.9* T6 75.6 ± 20.1 72.8 ± 19.7*

* p<0.05 in group com pared with T1

T a b l e V I. Rate pressure product (Mean ± SD)

T R A C H E A L T U B E L M A ( n = 1 5 ) (n = 1 5 ) T 1 13462 ± 2748 15894 + 4434 T2 11426 ± 2837 11823 ± 1979* T3 15629 ± 4815 13971 ± 4031 T4 16559 ± 5583* 13640 ±4938 T5 14636 ± 5709# 10578 ± 4251* T6 11402 ± 4436 9369 ± 3139*

* P<0.05 in group com pared with T1 # p<0.05 between groups

DISCUSSION

Ischemic heart diseases mostly CAD, angina pectoris and CHF causing increased perioperative morbidity and mortality are risk factors for patients undergoing elective non-cardiac surgery (4,10). The patients enrolled in this study; were assessed by a cardiologist preoperatively and were assigned to the groups equally according to their echocardiography and Goldman and Detsky's cardiac risk assessment scores. According to our results the use of LMA for airway maintenance in cardiac patients causes less deleterious effects than endotracheal intubation. Laryngoscopy and endotracheal intubation impasses deleterious effects on myocardial perfusion in patients with ischemic heart disease. Increases in catecholamine secretion during this period lead to hypertension and most importantly tachycardia which shortens the diastolic filling time causing impaired myocardial perfusion. Harris et al (11) concluded that there was a significant increase in systolic arterial pressure and heart rate after laryngoscopy and intubation if only etomidate, thiopental or propofol used alone for anesthesia induction. The authors (11) have done studies to prevent the increase in rate pressure product as it impairs myocardial perfusion. Mikawe et al (1 2) pointed out that 0 . 2 mg/kg diltiazem i.v. during

induction reduced the increase in systolic arterial pressure, HR and RPP to a minimum level. In the studies of Black (13), Crawford (14) and Miller (15) alfentanil 15 pg/kg i.v. administered during induction was found to be the most effective drug in attenuating the increases in catecholamine secretion and vasopressor response. Narcotic analgesics causing less myocardial depression than other anesthetic drugs can be used safely in patients with ischemic heart disease (16,17).

As LMA does not stimulate the subglottic area, hemodynamic changes are minimal with its use.

B in n a z A y , e t a l

Wilson et al (18) in a study of forthy patients having normal cardiovascular function compared the hemodynamic effects after laryngoscopy and intubation with LMA insertion. They concluded that there was a significant increase in systolic arterial pressure after intubation. There was an increase in HR in both groups without a statistical significance. On the other hand Braude et al (19) claimed that there was an increase in systolic arterial pressure and HR after intubation and LMA insertion but there was not statistical difference between the two groups.

In our study: MAP increased significantly during, 1 st and 3rd minute after intubation but there was no increase in MAP and HR in the LMA group. The discrepancy between our study, Wilson’s (18) and Braude's (19) study was due to the measurement of blood pressure continuously via a radial artery catheter in our study and Wilson's study but in regular intervals in Braude's study.

In our study there was no increase in HR in LMA group and the increase in HR of the intubated group was much less when compared with the other two studies. We think that this is due to the effect of alfentanil we used during induction. Also RPP decreased in LMA group while it increased significantly at 1 st minute of

intubation. Ray et al (20) stated that the patients with CAD having RPP>11000 had ST segment depression at the time of intubation. In our study although all patients had RPP>11000, only 6 patients in group I

and 3 patients in group II had ST segment depression. We concluded that unless contraindicated; airway maintenance with LMA causing less hemodynamic and ST segment changes compared to endotracheal intubation should be preferred in patients with CAD/CHF in order to protect myocardial perfusion.

REFERENCES

4. C o ria t P, D a lo z M. P re v e n tio n o f in tra o p e r a tiv e m y o c a r d ia l is c h e m ia d u rin g n o n -c a rd ia c s u rg e ry w ith in tr a v e n o u s n it r o g ly c e r in . A n e s th e s io lo g y 1 9 8 4 /6 1 :1 9 3 -1 9 6 . 5. S p e n c e r L, R a n d a ll RC. E p id u r a l a n e s th e s ia a n d a n a lg e s ia . A n e s th e s io lo g y 19 9 5 / 8 2 : 14 7 4 - 15 0 6 . 6. F le is c h e r LA. I s c h e m ic h e a r t d is e a s e . A n e s t h e s io lo g y C lin ic s o f n o r t h A m e r ic a 1 9 9 7 /1 5 :4 9 -6 7 .

7. C o llin s VJ. E n d o tra c h e a l a n e s th e s ia : C o m p lic a tio n s . In : P rin c ip le s o f A n e s th e s io lo g y . C o llin s VJ. 3 r d ed. P e n n s y lv a n ia : Lea a n d F e b rig e r 1 9 9 3 /5 6 5 -5 9 6 . 8. C a r lin e r n t t , F is h e r ML. R o u tin e p r e o p e r a t iv e e x e rc is e te s tin g in p a tie n ts u n d e rg o in g m a jo r n o n ­ c a rd ia c s u rg e ry . A m J C a r d io l 19 8 5 /5 6 :5 1 -5 7 . 9. T y e rs MR, R u s s e l WJ. E le c t r o c a r d io g r a p h ic m o n it o r in g in a n e s th e s ia . A n e s th In te n s C a re 1 9 8 8 /1 6 :6 6 -6 9 . 10. S lo g o ff S, K e a ts /4S. D o e s p e r io p e r a tiv e m y o c a rd ia l is c h e m ia le a d t o p o s t o p e r a t iv e m y o c a r d ia l in fa rc tio n ? A n e s th e s io lo g y 19 8 5 / 6 2 : 10 7 - 1 14. 11. Flam 's CE, M u rra y JM . E ffe c ts o f th io p e n to n e ,

e to m id a te a n d p r o p o f o l o n t h e h e m o d y n a m ic r e s p o n s e t o t r a c h e a l in t u b a t io n . A n a e s th e s ia 1 9 8 8 /4 3 :3 2 -3 6 .

12. M ik a w e K, Ik e g a k i J. The e ffe c t o f d iltia z e m o n th e c a rd io v a s c u la r re s p o n s e t o t r a c h e a l in tu b a tio n . A n a e s th e s ia 19 9 0 /4 5 :2 8 9 - 2 9 3 . 13. B la c k TE, K a y B. R e d u c in g th e h e m o d y n a m ic r e s p o n s e t o la r y n g o s c o p y a n d in t u b a t io n . A n a e s th e s ia 19 8 4 /3 9 :8 8 3 - 8 8 7 . 14. C ra w fo rd DC, F e ll D. E ffe c ts o f a lfe n ta n il o n th e p r e s s o r a n d c a te c h o la m in e r e s p o n s e s to tra c h e a l in tu b a tio n . B r J A n a e s th 1 9 8 7 /5 9 :7 0 7 -7 1 2 .

15. M ille r DR, M a rtin e a u RJ. E ffe c ts o f a lfe n a n il o n th e h e m o d y n a m ic a n d c a t e c h o la m in e r e s p o n s e to tra c h e a l in tu b a tio n . A n e s th A n a ig 19 9 3 / 7 6 : 10 4 0 -

1 0 4 6 .

16. F lic k s FiJ, M o w b ra y A. C a rd io v a s c u la r e ffe c ts a n d c a te c h o la m in e re s p o n s e to h ig h d o s e fe n ta n y l-0 2 f o r in d u c t io n o f a n a e s th e s ia in p a t ie n t s w ith is c h e m ic c o ro n a r y -a r te ry d is e a s e . A n e s th A n a ig 1 9 8 1 /6 0 :5 6 3 -5 6 8 . 1 7. S h a fe r SL, V a rv e l JR. P h a r m a c o k in e tic s , p h a rm a c o d y n a m ic s a n d r a tio n a l o p io id s e le c tio n . A n e s th e s io lo g y 19 8 1; 7 4 :5 3 -6 3 . 18. W ilso n IG, F e ll D. C a rd io v a s c u la r re s p o n s e s to in s e r t io n o f t h e la r y n g e a l m a s k . A n a e s th e s ia 1 9 9 2 /4 7 :3 0 0 -3 0 2 . 19. B ra u d e FI, C le m e n ts AF. T he p re s s u r e re s p o n s e a n d la r y n g e a l m a s k in s e r t io n . A n a e s th e s ia 1 9 9 0 /4 4 :5 5 1 -5 5 4 . 2 0 . R ay TK, J a c o b s KFI. R e in f a r c t io n f o llo w in g a n e s th e s ia in p a tie n ts w ith m y o c a r d ia l in fa rc tio n . A n e s th e s io lo g y 19 8 3 /5 9 :4 9 9 - 5 0 5 .