Carátula del artículo
An Easy and Reliable Way to Prevent Electrocardiographic
Deteriorations of Patients Undergoing Off-Pump Coronary Artery Bypass Surgery:
Preoperative Anxiolytic Treatment
Abdullah Demirhan
Abant Izzet Baysal University, Turkey
Yusuf Velioglu
Abant Izzet Baysal University, Turkey
Hamit Yoldas
Abant Izzet Baysal University, Turkey
Ibrahim Karagoz
Abant Izzet Baysal University, Turkey
Mehmet Cosgun
Abant Izzet Baysal University, Turkey
Duygu Caliskan
Abant Izzet Baysal University, Turkey
Isa Yildiz
Abant Izzet Baysal University, Turkey
Murat Bilgi
Abant Izzet Baysal University, Turkey
Kemalettin Erdem
Abant Izzet Baysal University, Turkey
Brazilian Journal of Cardiovascular Surgery, vol. 34, no. 3, pp. 311-317, 2019
Sociedade Brasileira de Cirurgia Cardiovascular
Received: 12 September 2018
Accepted: 04 November 2018
INTRODUCTION
Major cardiac surgery causes fear, stress and anxiety on many
patients[1-5]. Due to concern, fear and due to
some unknown reasons, it is stated that patients may experience high levels of
anxiety prior to cardiac surgery[6]. It has been previously shown that one or two days before
cardiac surgery the anxiety levels of patients rises up to 20-50%[2,3].
Anxiety, depression and negative thoughts may also cause pathological
changes[7]. It has
been found that increased anxiety leads to sympathetic hyperactivity through
elevated levels of serotonin, dopamine, plasma norepinephrine and metabolites in
patients[8,9]. This, in return, decreases the
ventricular fibrillation threshold via prolonged and increased dispersion of
repolarization[10].
It has been shown in the literature that increased anxiety and stress levels may
increase the likelihood of cardiac arrhythmia through prolonged QT dispersion
(QTd)[11,12].
It is known that coronary bypass surgery causes more catecholamine release during
laryngoscopy and tracheal intubation (TI) compared to other operations, resulting in
a sudden increase in blood pressure and heart rate (HR)[13,14]. Previous studies have also shown that increased plasma
levels of catecholamine increase P-wave dispersion (Pd) on electrocardiography,
prolong corrected QT (QTc) distance, and QT dispersion. Moreover, Pd changes have
been associated with atrial arrhythmias, however, changes in QTc and QTd were
associated with ventricular arrhythmia and sudden death[15-17].
Electrocardiography (ECG) is a reliable indicator that is frequently used to detect
pathological electrical activity. The QT interval is an indicative of ventricular
repolarization, and its extension is considered a risk factor for
arrhythmias[18]. QT
dispersion is defined as the difference between the longest QT and the shortest QT
of the 12-lead ECG reflecting the different regions of ventricular repolarization.
Laryngoscopy and TI in anesthesia induction increases HR and mean arterial pressure
(MAP) values, as well as changes the electrophysiological properties of the
heart[19-23]. In the literature, inhalers
have been shown to extend QT interval following anesthetic agents and
TI[24,25].
In this study, we investigated the effects of relieving preoperative anxiety on
electrophysiological changes in patients who will undergo off-pump coronary artery
bypass surgery. In these patients, high levels of stress are induced during
pre-induction, as well as laryngoscopy and tracheal intubation.
METHODS
The present randomized controlled study was performed after approval of the Abant
Izzet Baysal University Ethics Committee for Clinical Researches by 2017/05. All
patients provided their written and oral consent to participate in the study during
preoperative examination. All patients underwent off-pump coronary artery bypass
grafting surgery under general anesthesia, performed in Abant Izzet Baysal
University at the Training Research Hospital. A total of 61 patients in ASA III risk
group in the age range of 18-65 years were enrolled in the present study. Sixty-one
patients, who agreed to participate in the study, were randomly divided into two
groups. The group administered with anxiolytic-sedative drug was called Group S
(Sedation group), and the group that was not administered any anxiolytic-sedative
drug was called Group C (Control group). Group S was administered 0.04 mg/kg
lorazepam per os (PO) twice; once the night before the operation,
then 2 hours before the operation. Group C was not administered with any anxiolytic
premedication.
Evaluations were performed and recorded using both the State Trait Anxiety
Inventory-TX1 (STAI-I) form, consisting of 20 parameters, and the Beck Anxiety
Inventory (BAI), consisting of 21 parameters for the state anxiety measurement of
the patients. STAI-I is used to show the individual differences in anxiety levels,
which is intensified in response to potentially threatening events[26]. In this questionnaire, a total
score of 20 to 80 was given to each participant using a 4-point Likert scale. In
this test, higher scores are indicative of elevated anxiety levels[26-28]. BAI was scored from 0 to 3 using a 4-point Likert scale.
This test is used to focus on somatic symptoms of anxiety[29].
On the day of operation, the STAI-I and BAI evaluations were performed by a
practitioner who did not know the patient's groups. In the operating room, 16-18 G
intravenous catheters were inserted into separate arms and 0.05 mg/kg morphine was
administered intravenously to provide sedation. For all patients, ECG for heart rate
(HR), pulse oximetry (SpO2) for peripheral oxygen saturation and standard
monitoring were performed. Moreover, to monitor the arterial blood pressure, Allen
test was performed from a normal arm under topical anesthesia using a 20G catheter.
The systolic blood pressure (SBP), diastolic blood pressure (DBP) and MAP parameters
were also recorded. Furthermore, during preanesthetic induction, patients were
connected with standard 12-lead ECG (Nihon Kohden, Model EKG-1350K, Japan) to
confirm sinus rhythm and pre-induction ECG recording was obtained. ECG recordings
were performed at a speed of 25 mm/sec.
Anesthesia induction was started using 1-2 mg/kg propofol and 2 mcg/kg fentanyl.
After loss of consciousness, muscle relaxation was achieved with 0.6 mg/kg
rocuronium. This is followed by face mask ventilation for 3 minutes. Then, patients
were intubated using a tube of similar size (size 8). Following the 12-lead ECG
induction of the patients, after induction at the 1st and 3rd
minutes, as well as after intubation, at the 30th second in the
2nd and 4th minutes, records were taken. Then, the
anesthesia was continued with air and 1-2% sevoflurane in 50% oxygen. At the same
time, central venous catheter was inserted, and hemodynamic parameters, including HR
and MAP, were measured and recorded before induction, after induction at the
1st and 3rd minutes, as well as after intubation and at
the 30th second in the 2nd and 4th minutes. QT and
P dispersion in each derivation of all ECGs was calculated by a cardiologist and
anesthesiologist. The QT dispersion was calculated as the difference between the
maximum and minimum QT values (QTd = maximum QT - minimum QT). Likewise, P
dispersion was calculated as the difference between the maximum and minimum
P-values.
Statistical Analysis
The Statistical Package for Social Science (SPSS 23.0) program was used to
perform statistical analysis. The descriptive variables age, body mass index
(BMI), QT dispersion, P dispersion, and MAP were calculated as mean ±
standard deviation. The Kolmogorov-Smirnov test was used to determine whether
variables were normally distributed. Independent-Samples T-test was used to
analyze the normally distributed variables between the groups. Analysis of
variance for repeated measures was used to compare QT dispersion, P dispersion
and MAP at different intubation time periods. When a significant overall effect
was detected, Tukey’s post-hoc test was conducted for comparison of the mean
values for the two variables. The chi-squared and Fisher's exact tests were used
for the analysis of the categorical variables. A P-value less
than 0.05 (P<0.05) was considered as the statistical
significance limit. Compared with previous studies[30], to achieve α<0.05
and β=80% according to QT dispersion, 22 subjects were required in the
control group, and 22 subjects were required in the sedation group.
RESULTS
There was no significant difference between groups in terms of age, gender, BMI and
duration of intubation (P>0.05) (Table 1). Preoperative STAI-I scores were significantly lower in
sedation group compared to the controls (P<0.05) (Table 2). When BAI and STAI scores were
compared within the group, no significant difference was observed in Group S
(P=0.102). However, the scores were significantly higher in
Group C (P<0.001) (Table
2).
Table 1
Baseline and intraoperative characteristics of patients.
Values are expressed as mean (SD) or n (%).
Table 2
The difference in BAI and STAI-I values between control and sedation
groups.
* Indicates statistical significance. STAI and BAI values were significantly higher in the Group C compared to
the Group S ( P <0.05).
In the intergroup evaluation of the cases, MAP values during intraoperative period
showed no significant difference (P>0.05) (Figure 1). Heart rate was only significantly reduced in Group S
following the 30th second of intubation (Figure 2).
Fig. 1
Comparison of mean arterial pressure between groups.
Fig. 2
Comparison of heart rate between groups.
The differences between these groups were examined by multiple comparison tests.
According to these results, mean values of QTd measured before induction, at the
1st minute of induction, 30th second of intubation and
4th minute of intubation in sedation group were significantly reduced
compared to controls (P=0.024; P=0.027;
P=0.001; P=0.033, respectively) (Table 3).
Table 3
Comparison of QT dispersion between groups in different time periods of
intubation.
* There was a statistically significant difference between Group C and
Group S ( P <0.05).
The mean values of P dispersion measured before induction, at the 3rd
minute of induction, 30th second of intubation and 4th minute
of intubation in sedation group were significantly reduced compared to the controls
(P=0.001; P=0.020; P=0.023;
P=0.005, respectively) (Table
4).
Table 4
Comparison of P dispersion between groups in different time periods of
intubation.
* There was a statistically significant difference between Group C and
Group S ( P <0.05).
DISCUSSION
The current study showed that the high anxiety levels of patients who underwent
coronary bypass surgery had increased QTd and Pd intervals. On the other hand,
removal of preoperative anxiety shortened QTd and Pd intervals in pre-induction and
following laryngoscopy and TI procedures.
The main reasons of increased level of preoperative anxiety in cardiac surgeries in
patients awaiting coronary artery bypass surgery are unawareness of surgery and the
fear caused by the lack of knowledge. It is considered normal for intense anxiety in
patients a couple of days before the surgery or during the surgery preparations.
Lichtor et al.[31]
reported that the anxiety level of the patient during the day before surgery was not
different from the level of anxiety prior to entering the operating room in the day
of surgery. Some of the patients experienced high levels of anxiety and this
increased levels has been associated with increased QT dispersion leading to cardiac
arrhythmias[11]. It
has also been shown that mental stress can increase QT dispersion[12]. In the present study, we
observed that BAI and STAI scores of anxiety-deprived patients, who were waiting for
coronary bypass surgery, showed a decrease in preoperative turnover compared to
preoperative turnout, where BAI and STAI scores were increased in the control group.
The results of the present study suggest that increased anxiety assessment scores in
the control group increased patients’ preoperative anxiety. As a result, it
significantly increased QTd and Pd intervals before induction. The results of the
current study for the effects of anxiety on QTd and Pd were similar to those
previously published in the literature[11,12]. Due
to the prolonged QT dispersion leading to ventricular arrhythmias and the risk of
sudden death[32,33], we have shown that it is
important to reduce patients’ anxiety levels before surgery.
In the literature, the effect of implementation of laryngoscopy, a procedure that
prolongs the QTD and Pd interval, and TI[15-17,30] in QT or P dispersions in a
patient undergoing anxiety-relieved coronary bypass surgery has not been reported.
Catecholamine release and stress response during laryngoscopy and TI can lead to
severe complications in patients with cardiovascular and cerebral disease, as well
as increase the risk of mortality and morbidity[15,34]. It has been reported that QT dispersion could be used
for HT patients as an indicator for the prevention of sudden cardiac
death[35,36]. In addition, the QTd interval
after TI is prolonged and is even more severe in patients with coronary artery
disease and HT[21].
Similar to the QT dispersion, prolonged Pd interval is considered to be indicative
of supraventricular arrhythmias. In many studies, Pd interval has been reported to
be a useful and simple method for determining the risk of paroxysmal atrial
fibrillation[37].
Changes in the P-wave interval in patients with diastolic dysfunction, myocardial
ischaemia and acute coronary syndrome have been shown in the
literature[38,39]. Previous studies have shown
that volatile anesthetics and TI may prolong the QT interval period[24]. On the other hand, the use of
propofol, as an intravenous anesthetics, may be more appropriate without prolonging
the QT interval[40] and
shortens the Pd interval[41]. Likewise, administration of fentanyl at a dose of 2
mcg/kg before induction of propofol has been shown to reduce the length of
laryngoscopy and TI-dependent QTc interval[42]. In the current study, we also used drugs with
positive effects on laryngoscopy and QT and P dispersion durations during TI.
Moreover, we also observed that propofol and fentanyl decreased laryngoscopy and
TI-dependent QT and P dispersions. We found that the elimination of anxiety
contributed more positive effects to decrease the QT and Pd times. In the
literature, although it has been reported that some benzodiazepines may lead to
alterations on electrocardiographic parametres[43,44], there are several studies reporting that lorazepam does
not directly affect electrocardiographic parametres. including PR prolongation, QRS
widening and QTc interval[45-47].
Therefore, we designed this study on the preference of lorazepam as anxiolytic
agent.
In conclusion, the results of the present study demonstrate that high anxiety levels
in patients with coronary artery disease and coronary bypass surgery have a negative
effect through prolonged QT and Pd times. Moreover, anxiety removal before surgery
may be useful to prevent ventricular and atrial arrhythmias and associated
complications by decreasing the QT and P-wave dispersion durations both during
pre-induction and the peak periods of stress response due to laryngoscopy and
tracheal intubation.
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Notes
Notes
No financial support.
This study was carried out at the Department of Anesthesiology and Reanimation,
Abant Izzet Baysal University Medical School, Bolu, Turkey.
Conflict of interest declaration
No conflict of interest.
Author notes
Correspondence Address: Abdullah Demirhan,
https://orcid.org/0000-0002-2311-6431, Department of Anesthesiology and
Reanimation, Abant Izzet Baysal University Medical School, Golkoy, Bolu, Turkey,
Zip code: 14280. E-mail: dr_demirhan1@hotmail.com
