A Randomized Controlled Trial on the Effectiveness of Dexmedetomidine Versus Fentanyl in Attenuating the Sympathetic Response to Direct Laringoscopy and Endotracheal Intubation

Artikel Penelitian

Maj Kedokt Indon, Volum: 60, Nomor: 3, Maret 2010

A Randomized Controlled Trial on theEffectiveness of Dexmedetomidine VersusFentanyl in Attenuating the Sympathetic

Response to Direct Laringoscopy andEndotracheal Intubation

Suparto,* Olivia C. Flores,** Clarissa Angela A. Layusa**

*Fakultas Kedokteran Kristen Krida Wacana (UKRIDA)

**University of the East Ramon Magsaysay Memorial Medical Center, Inc.

Abstract: Laryngoscopy and intubation is associated with increase in blood pressure and heart

rate. This study aimed to demonstrate the efficacy of dexmedetomidine in attenuating this hemo-

dynamic response. This was a randomized double-blind trial involving 56 patients for general

anesthesia who were allocated to receive either dexmedetomidine I mcg/Kg and fentanyl 1 mcg/

Kg intravenously prior to anesthesia induction. All patients received incremental doses of

propofol, atracurium and O2-sevoflurane. Systolic and diastolic blood pressures, heart rates, as

well adverse events were monitored. There were a 13% decrease in SBP, 11% decrease in DBP,

and 23% decrease in cardiac rate in the Dexmedetomidine group compared to a decrease of

19% SBP, 16% in DBP, and 6% in cardiac rate among those in the Fentanyl group. The decrease

in the cardiac rates in the Dexmedetomidine group was significantly lower. Although SBP, DBP

and cardiac rates increased with laryngoscopy and intubation, the circulatory response was

attenuated in patients given Dexmedetomidine with mean increase of 25% and 29% in SBP and

DBP respectively. The increase in both SBP and DBP in the Fentanyl group was 40%. The

cardiac rates also increased from induction levels but the increase in the Dexmedetomidine

group was significantly lower. The SBP, DBP, cardiac rate levels of patients given Dexmedetomidine

at 60 seconds postintubation showed lower values than baseline, while the SBP, DBP and

cardiac rates of subjects given Fentanyl exhibited sustained increase values that were greater

than baseline. Bradycardia and hypotension were noted in the dexmedetomidine group with OR

of 9.0 (95%CI: 1.026-78.94), and 1.5, (95%CI: 0.24-10.37) respectively. It was concluded that

Dexmedetomidine at 1 mcg/Kg and Fentanyl at 1 mcg/Kg both produced lowering of blood

pressures and cardiac rates, with significantly lower mean heart rates with Dexmedetomidine.

Laryngoscopy and intubation produced less blood pressure increases in the Dexmedetomidine

group and significantly lower cardiac rates. Dexmedetomidine reduced the amount of Propofol

to produce unconsciousness.

Keywords: dexmedetomidine, fentanyl, blood pressure, heart rate, direct laryngoscopy, endotra-

cheal intubation

126


Uji Coba Acak dalam Menentukan Efektivitas Dexmedetomidine

terhadap Fentanyl dalam Menekan Respons Simpatis pada

Laryngoskopi dan Intubasi

Suparto,* Olivia C. Flores,** Clarissa Angela A. Layusa**

*Fakultas Kedokteran Kristen Krida Wacana (UKRIDA)

**University of the East Ramon Magsaysay Memorial Medical Center, Inc.

Abstrak: Laringoskopi dan intubasi berhubungan dengan kenaikan tekanan darah dan denyut

jantung. Studi ini bertujuan menunjukkan efektivitas dexmedetomidine dalam menumpulkan respon

hemodinamik tersebut. Penelitian ini dilakukan secara acak, double-blind, melibatkan 56 pasien

yang menjalani anestesi umum, yang terbagi menjadi dua kelompok dan masing-masing

mendapatkan dexmedetomidine 1mcg/Kg atau fentanyl 1 mcg/Kg intravena sebelum dilakukan

induksi anestesi. Semua pasien menerima dosis bertingkat dari propofol, atrakurium dan O2-

sevoflurane. Tekanan darah sistolik, diastolik, denyut jantung, dan efek samping dimonitor.

Terdapat penurunan tekanan darah sistolik sebesar 13%, tekanan darah diastolik 11%, dan

denyut jantung sebesar 23% pada grup Dexmedetomidine dibandingkan dengan penurunan

tekanan darah sistolik sebesar 19%, tekanan darah diastolik 16%, dan denyut jantung 6% pada

grup Fentanyl. Penurunan denyut jantung pada grup Dexmedetomidine secara signifikan lebih

rendah. Meskipun tekanan darah sistolik, diastolik dan denyut jantung meningkat dengan

laringoskopi dan intubasi, respons ini dilemahkan pada pasien-pasien yang diberikan

Dexmedetomidine, dengan rata-rata kenaikan tekanan darah sistolik sebesar 25% dan diastolik

sebesar 29%. Kenaikan tekanan darah sistolik dan diastolik pada grup Fentanyl sebesar 40%.

Denyut jantung juga meningkat tetapi peningkatan pada grup Dexmedetomidine secara signifikan

lebih rendah. Tekanan darah sistolik, diastolik dan denyut jantung 60 detik sesudah intubasi

pada grup Dexmedetomidine menunjukkan tingkat yang lebih rendah dibandingkan awal,

sedangkan pada grup Fentanyl menunjukkan nilai yang tetap meningkat dibandingkan awal.

Bradikardi pada grup Dexmedetomidine terjadi dengan OR 9,0 (95%CI: 1,026-78,94) dan

hipotensi terjadi dengan OR 1,5 (95%CI: 0,24-10,37). Sebagai kesimpulan, baik Dexmedetomidine

1 mcg/Kg maupun Fentanyl 1 mcg/Kg dapat menurunkan tekanan darah dan denyut jantung,

namun denyut jantung rata-rata pada grup Dexmedetomidine secara signifikan lebih rendah.

Laringoskopi dan intubasi pada grup Dexmedetomidine menunjukkan peningkatan tekanan darah

lebih rendah dan denyut jantung yang secara signifikan. Dexmedetomidine mengurangi dosis

Propofol dalam menurunkan kesadaran pasien.

Kata kunci: dexmedetomidine, fentanyl, tekanan darah, denyut jantung, laringoskopi direk, intubasi

endotrakeal.

Introduction

Laryngoscopy and tracheal intubation are associated

with a sympathetically mediated increase in blood pressure

by 40-50% and heart rate by 20% that may be deleterious in

patients with underlying cardiovascular and cerebrovascu-

lar disease.1,2 To ameliorate this pressor response, various

methods have been tried including adrenergic blockers, va-

sodilators, calcium channel blockers, alpha 2 agonists, nar-

cotics and inhalation anesthetics.1-14

One of the most studied drugs to attenuate the hemo-

dynamic response to laryngoscopy and tracheal intubation

during anesthetic induction is fentanyl.4-9 Fentanyl is a short-

acting synthetic opioid agonist 75-125 times more potent

than morphine. It has a rapid onset but has a distinct time

lag between the peak plasma fentanyl concentration and peak

slowing on the EEG of around 3- 7 minutes. This reflects the

delay in the attainment of a drug concentration in the plasma

and the clinical effect.15,16

Yildiz M et al.17 investigated the effect of a single pre-

induction intravenous dose of dexmedetomidine (1 mcg/kg)

on the cardiovascular response from laryngoscopy and en-

dotracheal intubation, need for supplemental anesthetic

agent, and perioperative hemodynamic stability. Their results

showed that preoperative administration of single dose of

dexmedetomidine resulted in progressive increase in seda-

tion, blunted the hemodynamic responses during laryngos-

copy, and reduced opioid and anesthetic requirements. Fur-

thermore, dexmedetomidine decreased blood pressure and

A Randomized Controlled Trial on the Effectiveness of Dexmedetomidine Versus Fentanyl

127



a

b

heart rate as well as the recovery time after the operation.17

Dexmedetomidine is a relatively new, highly selective,

short-acting central alpha 2 agonist. Activation of α2-recep-

tors leads to: dose dependent sedation and anxiolysis, anal-

gesia (supraspinal and spinal sites), decrease plasma cat-

echolamines, centrally mediated bradycardia and hypoten-

sive effects, diuresis from the inhibition of ADH release and

antagonism of ADH tubular effects, and decongestion and

antisialogogue effects.18 Dexmedetomidine has increasingly

gained popularity among anesthesiologists and intensive

care physicians abroad as adjuvant to general and regional

anesthesia techniques, and as a sedative. Its administration

potentiates the effect of other sedative and hypnotic agents

while causing minimal respiratory depression. It also reduce

the sympathetic response-thus minimizing changes in blood

pressure and heart rate-during critical moments such as laryn-

goscopy and intubation. However, bradycardia and hypoten-

sion may ensue.19,20

Now that this relatively new drug has been made avail-

able in our institution, the proponents of this study would

like to test its purported favorable effects on blood pressure

and cardiac rate during direct laryngoscopy and intubation.

The study would like to determine the efficacy of dexme-

detomidine in attenuating hemodynamic response to direct

laryngoscopy and endotracheal intubation. Furthermore, it

seeks to determine the differences in systolic and diastolic

blood pressures and heart rates after laryngoscopy and en-

dotracheal intubation between the patient groups given

dexmedetomidine and fentanyl. Dexmedetomidine and

fentanyl’s ability to decrease the anesthetic requirements

was determined by comparing the amount of induction agent

(propofol) needed to abolish the eyelash reflex. Finally, the

authors aimed to compare the presence and degree of ad-

verse events between the two drugs.

Materials and Methods

This is a randomized controlled trial to compare the

hemodynamic effects of Fentanyl and Dexmedetomidine

during direct laryngoscopy and intubation of the trachea.

The anesthesiologists who did the direct laryngoscopy and

intubation, the observers, and the data analysts, were all

blinded as to the drug given to the patients. Ethics approval

was obtained prior to the conduct of the study.

Sample size was calculated with a power of 80% and a

probability of 0.05 alpha error assuming a homogeneity of

variance for both dexmedetomidine and fentanyl and an ef-

fect size equal to 20, yielded 28 for each group.

The population comprised of surgical in-patients and

out-patients of the UERMMMC Hospital from July to Sep-

tember 2008. All patients were to undergo general endotra-

cheal anesthesia, aged 18 and above, with ASA risk I-III

elective or emergency, and with voluntary, written, informed

consent were included in the trial. Excluded were patients

who were severely hypovolemic, those with anticipated dif-

ficult airway, patients diagnosed with 2nd-3rd heart block,

and sinus bradycardia <50/min. Subjects who had longer

than 30 seconds laryngoscopy, and/or multiple attempts at

laryngoscopy/intubation were considered drop-outs, but

would be included in the final analysis.

Experimental Maneuver

After a thorough pre-operative evaluation, an informed

consent was obtained from each patient. Standard premedi-

cation with Nalbuphine (5-10 mg) and/or Hydroxyzine (25-50

mg) or Promethazine 25-50 mg IM were administered to the

patients. Upon arrival at the operating room, allocation of

subjects was made randomly with the aid of a randomized

table contained in a sealed, opaque, individualized envelope.

Patients were hooked to standard monitors such as NIBP,

ECG, and pulse oximetry. Patients who belonged to the Dex

group were given dexmedetomidine 1 mcg/Kg diluted with

NSS to make 10 ml volume, administered slow IV for 10 min-

utes. On the other hand, those who belonged to the Fent

group were given Fentanyl 1 mcg/Kg diluted with NSS also

to make 10 mL volume, injected slow IV for 10 minutes. This

was followed by Propofol 1% injection given in incremental

dose until loss of eyelash reflex was attained. Sevoflurane at

0.5% was turned on and Atracurium 0.5 mg/Kg was given.

Four minutes after atracurium injection, sevoflurane was in-

creased to 2.5 vol % to deepen the anesthesia. Five minutes

after Atracurium (expected onset of paralysis), the anesthe-

siologist commenced the direct laryngoscopy and intuba-

tion. As previously mentioned, more than 30 seconds at-

tempt at laryngoscopy and intubation will be dropped out

since hemodynamic responses from these stimuli are expected

to increase markedly.

Subjects with significant bradycardia (HR <50/min) dur-

ing induction were to be given atropine 400 mcg IV. Subjects

who developed significant hypotension (reduction of >20%

from their usual BP or BP <90 mmHg systolic) during induc-

tion were first treated with fluid loading (10mL/Kg), lowered

concentration of the inhalational gas, and/ or Ephedrine (5-

10mg IV) if BP became worse or did not improve.

Another observer unaware of the drug given took note

of the blood pressures and cardiac rates of subjects at

baseline, 15 minutes after injection of inducing agents (test

drugs+ muscle relaxant), and 30 and 60 seconds after suc-

cessful intubation. Other data noted were the total amount

of propofol used per patient, and adverse events during and

up to 4 hours after induction.

Results

The results were examined using the SPSS v.13. The BP

and cardiac rates were analyzed with t-test assuming equal-

ity of variance between the two test drugs. P values <0.05

were considered significant. The odds ratio of the adverse

events on the other hand were computed using Mantel-

Haenszel estimate and verified further with the Pearson Chi-

128



square test with p values of <0.05 considered significant

association.

Table 1. Frequency of Demographic Characteristics

Variable Dexmedetomidine Fentanyl

Age

18-34 8 (29%) 6 (21%)

35-51 10 (35%) 11(40%)

52-68 8 (29%) 6 (21%)

69-85 2 (7%) 5 (18%)

Gender

Male 11 (40%) 12 (43%)

Female 17 (60%) 16 (57%)

ASA Classification

ASA I 10 (36%) 10 (36%)

ASA II 16 (57%) 15 (54%)

ASA III 2 (7%) 3 (10%)

Table 2. Demographic Profile

Dexmedetomidine Fentanyl P. value

Age 45±16.24 49.61±18.01 0.319

Sex (M/F) (n) 11/12 17/16

Weight 60.11±12.75 58.54±11.96 0.636

Table 1 and 2 show that there was adequate represen-

tation of subjects in both groups based on age, gender, and

ASA class. The demographic data were similar, which

showed no significant difference between the groups.

Figure 3. Comparison of Mean Systolic and Diastolic Pres

sures and Heart Rates at Baseline, 15 Min Post-

Induction, 30 Sec and 60 Secs Post-Intubation

The baseline blood pressures and heart rates among

the patients in both groups were comparable. Fifteen mi-

nutes after administration of the test drugs, the systolic and

diastolic blood pressures as well as heart rates in both group

decreased similarly. The decrease in the SBP in patients given

Fentanyl was significantly lower with p-value of 0.04. On

the other hand, the decrease in the heart rate in the

Relative Time

0

20

40

60

80

100

120

140

160

BL 15 min T30 T60

SBP (Dex)

DBP (Dex)

HR (Dex)

SBP (Fen)

DBP (Fen)

HR (Fen)

Mean p

ressure

s (m

mH

g) and h

eart

rate

(bpm

)

Dexmedetomidine group was significantly lower with p-value

of 0.000.

The systolic and diastolic blood pressures and heart

rates increased in both groups after laryngoscopy and intu-

bation. The mean increase in the systolic and diastolic pres-

sures at 30 and 60 seconds post intubation in patients given

either drug were similar and not statistically significant. On

the other hand, the increase in heart rate at 30 sec and 60 sec

from the start of laryngoscopy was significantly different

between the two groups (p<0.05), with patients in the

dexmedetomidine group exhibiting less tachycardia.

Figure 4a. Difference in Systolic, Diastolic BP, and Heart

rate from one Point in Time to the Previous Time,

from Baseline to 60 Sec Post Intubation.

-30

-20

-10

0

10

20

30

40

50

BL BL to 15 min 15 min to 30

sec

30 sec to 60

sec

SBP

(dex)

DBP

(dex)

HR

(dex)

SBP

(fen)

DBP

(fen)

HR

(fen)

Time

% D

iffe

ren

ce

fro

m b

ase

lini

0

20

40

60

80

100

120

140

160

Base line 30 sec

SBP Dex

DBP Dex

HR Dex

SBP Fen

DBP Fen

HR Fen

Me

an

Pre

su

re (

mm

Hg

) /

He

art

Ra

te (

bp

m)

Time from Baseline

0

20

40

60

80

100

120

140

160

Base line 60 sec

SBP Dex

DBP Dex

HR Dex

SBP Fen

DBP Fen

HR Fen

Figure 4b. Difference in Systolic, Diastolic BP, and Heart

Rate from one Point in Time to the Previous Time,

from Baseline to 30 Secs and 60 Secs Postintuba-

t ion

Time from Baseline

*This difference between the 2 groups was statistically significantMe

an

Pre

su

re (

mm

Hg

) /

He

art

Ra

te (

bp

m)

129



The SBP, DBP and heart rates in both groups all de-

creased after injection of the test drugs but only the change

in heart rate in the Dexmedetomidine group was found to be

statistically significant with p-value of 0.000.

Thirty seconds after successful laryngoscopy and in-

tubation, the SBP, DBP and heart rates similarly increased

with slightly higher measurements in the Fentanyl group.

SBP and DBP increased by 40% in the Fentanyl group com-

pared to 25%-28% in the Dexmedetomidine group. However,

this difference was not significant.

Conversely, the cardiac rate in the Dexmedetomidine

group at 30 seconds postintubation was 11% lower than

baseline values. When compared to Fentanyl, the cardiac

rate was 12% higher than baseline levels. This difference

between the 2 groups was statistically significant with p-

value of 0.000.

Sixty seconds after intubation, the Dexmedetomidine

group had a decreased in the SBP by 5% and DBP by 10%

from the 30- second postintubation levels. In the Fentanyl

group, there was likewise a decrease in the SBP by 2% and

DBP by 1% from the 30-second postintubation levels. The

only significant change was seen in the much lower DBP in

the Dexmedetomidine group (p-value 0.04). The heart rates

in both groups increased, with a slightly greater increase in

patients belonging to the Fentanyl group.

Interestingly, the SBP, DBP, and heart rates of the pa-

tients in the Dexmedetomidine group at 60 seconds

postintubation returned slightly lower than baseline values.

In contrast, the mean SBP was 7%, DBP 12%, and heart rate

18% higher than baseline measurements in the Fentanyl

group. This difference between the 2 groups was statisti-

cally significant.

Table 5. Propofol Requirements (in mg)

N Mean±SD P- value

Dexmedetomidine 28 47.14±22.25 0.000

Fentanyl 28 86.07±20.61

Values are expressed as means ± SD; p<0.05 is significant.

The amount of propofol used was significantly less in

the Dexmedetomidine group with p-value of 0.000.

Bradycardia was significantly more common in the

Dexmedetomidine group with p-value of 0.022. The odds of

developing bradycardia is 9 times more likely to occur when

Dexmedetomidine 1 mcg/Kg IV in 10 minutes is given. The

lowest reading recorded was 43 (see Appendix 1).

Alternatively, there is no significant difference in the

occurrence of hypotension in the Dexmedetomidine and

Fentanyl group. Statistically, the is no significat difference

betwen the odds of developing hypotension with

Dexmedetomidine at 1 mcg/Kg IV and Fentananyl 1 mcg/Kg

IV.

Table 6. Frequency of Bradycardia and Hypotension Among

the Dexmedetomidine and Fentanyl Groups

Bradycardia Hypotension

Yes No Ye s No

Dexmedetomidine 7 (25%) 21 (75%) 3 (10.7%) 25 (89.3%)

Fentanyl 1 (3.6%) 27 (96.4%) 2 (7.1%) 26 (92.9%)

p-value (Pearson 0.022 0.639

Chi square)

Odds ratio (Mantel- 9.0 1.560

Haenszel Estimate) 95% CI 95% CI

(1.026, 78.943) (0.24, 10.137)

p<0.05 is significant; Confidence Interval (CI) = 95%

The adverse events were noted to have occurred be-

tween the periods of induction to before laryngoscopy when

there was minimal to no stimulus to the patients.

None of the subjects were dropped out from the study.

Discussion

Laryngoscopy and intubation are two of the most con-

sistent maneuvers that lead to significant increases in blood

pressure and heart rate. This had been attributed to a sympa-

thetic response as evidenced by an increase in the circulat-

ing catecholamine levels. These changes were reported to

be greatest 60 seconds after intubation of the trachea that

last for 5-10 minutes. 1 It is for these reasons that numerous

studies had been undertaken to search for effective and safe

drugs to attenuate this sympathetic response.

The major findings in this study show that patients given

either Dexmedetomidine 1 mcg/Kg or Fentanyl 1 mcg/Kg pro-

duced comparable lowering of DBP before direct laryngos-

copy and intubation with a more significant lowering in the

SBP of patients given Fentanyl. There was a 13% decrease in

SBP, 11% decrease in DBP, and 23% decrease in cardiac rate

in the Dexmedetomidine group compared to a decrease of

19% SBP, 16% in DBP, and 6% in cardiac rate among those in

the Fentanyl group. The decrease in the cardiac rates in the

Dexmedetomidine group was significantly lower.

The results above are consistent with the study of

Shehabi et al21 who claimed that Dexmedetomidine produced

predictable falls in BP and cardiac rate in patients given

Dexmedetomidine sedation in the ICU. Their results showed

16% (vs 13%) reduction in mean systolic blood pressure

(SBP) and 21% (vs. 23%) reduction in heart rate.

Although SBP, DBP and cardiac rates increased with

laryngoscopy and intubation, the circulatory response was

attenuated more in those patients given Dexmedetomidine

with a mean increase of 25% and 29% in the SBP and DBP

respectively. The increase in both SBP and DBP in the Fenta-

nyl group was 40%, the same as the average reported in-

crease in the blood pressures of patients as a manifestation

of the sympathetic response.1,2

The cardiac rates also increased from induction levels

but the increase in the Dexmedetomidine group was signifi-

130



cantly lower. When one would compare the effect of

Dexmedetomidine on heart rate from baseline values, there

was a reduction of 11 counts while the Fentanyl group

showed an increase of 12 counts from baseline. This maybe

secondary to the centrally-mediated bradycardic effect of

Dexmedetomidine.18,19 This also validates the findings of Yildiz

et al17 who reported that a single dose of dexmedetomidine 1

mcg/Kg given preoperatively produced blunting of the he-

modynamic responses during laryngoscopy and decrease

in heart rate, and findings of Feng et al,4 which showed that

Fentanyl at 3 mcg/Kg attenuated BP changes but not tachy-

cardia.

The SBP, DBP, cardiac rate levels of patients given

Dexmedetomidine at 60 seconds postintubation showed

lower than baseline values, while the SBP, DBP and cardiac

rates of subjects given Fentanyl exhibited sustained increase

values that were greater than baseline measurements. This

confirms that Dexmedetomidine produce a more favorable

hemodynamic profile than Fentanyl.

In contrast to the report of Shribman et al.1, the vital

signs recorded in this study showed marked changes at 30

seconds postintubation with recovery at 60 seconds

postintubation, compared to their results which showed

greatest vital sign changes at 60 seconds after intubation of

the trachea.

The total amount used to produce loss of eyelash re-

sponse to signal a state of unconsciousness was markedly

lower in those patients administered Dexmedetomidine. This

can be accounted for by the sedative effect of the drug as it

acts on the locus ceruleus. This is a small neuronal nucleus

in the upper brainstem which is an important modulator of

wakefulness.22

The adverse events noted in this study were bradycar-

dia in 7 patients who were treated with Atropine, and hy-

potension in 3 patients that were corrected with volume

therapy and decreasing the concentration of the inhalational

agent. These adverse events were all observed after admin-

istration of the test drug and induction agents (Propofol and

Atracurium) up to the time prior to laryngoscopy. The odds

for developing bradycadia with Dexmedetomidine at the dose

used is 9.0 (95%CI: 1.026-78.94). Bradycardia is more likely to

occur while hypotension similar in the Dexmedetomidine

and Fentanyl group. This may reflect the centrally- mediated

lowering of the cardiac rate and sympatholytic effect of

Dexme-detomidine.15,23 Moreover, the additive effects of

Propofol and the inhalational anesthetic may have contrib-

uted to the bradycardia and hypotension at the time when

there was minimal to no-stimulus to the patients.

Fentanyl is a commonly studied drug to blunt the circu-

latory effects of laryngoscopy and intubation. Several trials

have tried varying doses from 2 mcg/Kg- 8 mcg/Kg given 1

minute to 10 minutes before intubation.2,16 In these trials, the

Fentanyl dose found to be effective with minimal adverse

effect is 2 mcg/Kg. The present study utilized a lower dose

of Fentanyl at 1 mcg/Kg similar to the dose used by

Uzümcügil et al, which showed good effect in preventing

patient reaction with LMA insertion.24 The inadequate effect

of Fentanyl to attenuate the hemodynamic response in this

study maybe related to the lower dose used and longer-

than-optimal time lag from drug administration to laryngos-

copy.

Conclusion

Dexmedetomidine at 1 mcg/Kg and Fentanyl at 1 mcg/

Kg both produced lowering of blood pressures and cardiac

rates, with significantly lower mean heart rates with Dexme-

detomidine.

Laryngoscopy and intubation produced less blood

pressure increases in the Dexmedetomidine treated patients

and significantly lower cardiac rates than those treated with

Fentanyl. In addition, those given Dexmedetomidine showed

return of hemodynamic parameters to baseline levels, while

those given Fentanyl exhibited a sustained increase in blood

pressure and cardiac rate well above baseline levels.

Dexmedetomidine markedly reduced the amount of

Propofol to produce unconsciousness. However, it can pro-

duce reversible lowering of heart rate prior to onset of physi-

cal stimulus like laryngoscopy and intubation.

Recommendations

For other investigators interested in pursuing this trial,

the proponents of this study would like to recommend the

following:

• Different dosages of Fentanyl be tried in search for the

equipotent dose to 1 mcg/Kg of Dexmedetomidine.

• Lower Dexmedetomidine dose to decrease occurrence

of adverse events.

• Look into the efficacy of preoperative atropine adminis-

tration to prevent bradycardia with Dexmedetomidine 1

mcg/Kg.

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Documents

A Randomized Controlled Trial on the Effectiveness of Dexmedetomidine Versus Fentanyl in Attenuating the Sympathetic Response to Direct Laringoscopy and Endotracheal Intubation