Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT06375863 |
| Other study ID # |
44-2023 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
March 29, 2023 |
| Est. completion date |
May 29, 2023 |
Study information
| Verified date |
April 2024 |
| Source |
Haseki Training and Research Hospital |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
QT interval, defined as the time between the beginning of the QRS complex and the end of the
T wave in electrocardiography (ECG), is an indicator of depolarization and repolarization of
the myocardium.11 Prolongation of the heart rate corrected QT (QTc) interval reflects
electrical instability of ventricles and is associated with life-threatening ventricular
arrhythmias, including torsade de pointes, ventricular fibrillation and sudden cardiac death.
Spinal anesthesia can cause profound prolongation of the QTc interval due to disparity
between lumbar and thoracic sympathetic activity following subarachnoid block. Meanwhile
inhalational anesthetics, sevoflurane, isoflurane, and desflurane are known to prolong QTc
interval and intravenous anesthetics such as propofol, thiopental, etomidate and ketamin can
also cause remarkable prolongation of the QTc interval. Moreover laryngoscopy and intubation
may contribute to prolongation of the QTc interval because of the sympathetic stimulation.
Over the years it has been occurred an increase in the proportion of elderly population
requiring surgical anesthesia. The incidence of ventricular arrhythmias increases in
advancing age even in the absence of underlying heart disease and elderly patients have
reduced physiological functions and poor tolerance to anesthesia. However the choice of
anesthesia type is critical in this population.
To the best of knowledge, there was no published study to compare spinal anesthesia and
inhalational anesthesia in elderly patients with regard to the QT interval changes.
Investigators aimed to investigate the effects of spinal anesthesia on QT, QTc intervals and
to compare general anesthesia with sevofluran in elderly patients.
Description:
Investigators designed a prospective, randomized trial to compare spinal and general
anesthesia in elderly patients on the effects of QT interval changes. The study protocol was
approved by the Health Science University Haseki Training and Research Hospital Ethics
Committee, Istanbul, Turkey (date: 03/29/2023 and number: 44-2023). This study was conducted
according to the Declaration of Helsinki, and written informed consent was obtained from all
patients. The study was performed at a tertiary referral hospital with 700 beds in Istanbul,
Turkey between 03/29/2023-05/29/2023.
The patients who will undergo lower abdominal or extremity surgery and urological surgery
older than 65 years will be included in this study. The exclusion criteria are as follows:
any preoperative ECG abnormalities, QTc interval > 440 ms, family history of long QT syndome,
use of any medications known to affect the QTc interval, serum electrolyte abnormalities, any
contraindications for spinal anesthesia (e.g. coagulation disorders), unstable angina
pektoris, chronic obstructive pulmonary disease, hepatic or renal failure, American Society
of Anesthesiologists (ASA) physical classification status > III, pregnancy and obesity (BMI >
30).
Participants will be divided into two groups: the spinal anesthesia (group S) and general
anesthesia (group G). Randomization and group allocations will be performed by a researcher
who did not participate the collection of data.
In the preoperative care unit all patients will receive 10 ml/kg Ringer's lactate solution
via a peripheral vein over 30 minutes. In the operating room premedication will be obtained
with 0.015 mg/kg of midazolam and 1 µg/kg fentanyl intravenously.
In group G, a 2.0 mg/kg propofol injection will be used for the induction of anesthesia and
facilitating of endotracheal intubation was provided with 0.6 mg/kg rocuronium. After the
intubation the patients will be ventilated with a 6-8 ml/kg of tidal volume in volume control
ventilation (VCV) mode with an anesthesia machine (Dräger Primus, Dräger Medical Systems,
Inc. Danvers, MA, USA). Frequency of respiration will be adjusted to maintain PET CO2 at
32-36 mm Hg. Maintenance of anesthesia will be provided with sevoflurane (1.5-2%) in an
oxygen-air mixture (FiO2 = 0.4) and 0.015 mg/kg rocuronium as needed. At the end of the
surgery residual neuromuscular block will be antagonized with 4 mg/kg sugammedex.
In group S, spinal anesthesia will be performed in the sitting position at the level of L3-4
or L4-5 using a 25-gauge Whitacre (pencil point) spinal needle after the obtaining strict
sterile conditions and local anesthesia with intradermal lidocaine hydrochloride 1%.
Hyperbaric bupivacaine (Marcaine Spinal 0.5% Heavy; AstraZeneca, Turkey) 3-4 mL of 0.5% will
be injected to the subarachnoid space with the observation of cerebrospinal fluid outflow.
The patient was placed in the supine position immediately after drug injection. Dermatomal
level of sensorial block will be evaluated with pinprick test and modified Bormage scale was
used to assess motor blockade. Surgery will be allowed after the achievement of sensorial
block at the T10 level.
Monitoring and data collection Non-invasive blood pressure, heart rate (HR), peripheral
oxygen saturation (SpO2) and continuous ECG monitorization will be obtained for all patients
throughout the study via Mindray Bene View T8 (Shenzhen Mindray Bio-Medical Electronics Co.,
LTD, PR China. The QT interval will be measured automatically in lead II and calculation of
the QTc interval was also achieved automatically with using Bazett's formula
(QTc=QT/radqRR(sec)) from ECG monitorization. QT and QTc intervals will be measured and
recorded in the following manner: before the anesthesia induction or subarachnoid injection
(in group S), 1, 5, 10 minute after after endotracheal intubation or subarachnoid injection
(in group S), and immediately after surgery. Presence of arrhythmia will also be recorded.
Patient characteristics including age, gender, height, weight, body mass index (BMI),
comorbidity, ASA physical status classification and duration of surgery will be recorded.
Moreover maximum sensory block level and motor block recovery time will be investigated in
the group S. Also all cardiopulmonary adverse events will be evaluated including hypotension
(decrease in mean blood pressure > 20%), bradycardia (HR < 50 beats/min) and hypoxemia (SpO2
< 90%).
Statistical analysis SPSS software package for Windows (Statistical Package for Social
Sciences, version 22.0, SPSS Inc., Chicago, Illinois, USA) will be used for statistical
analysis of study data. Quantitative variables were emitted as mean ± standard deviation
(SD), whereas categorical variables as number of patients and percentage. Quantitative
variables will be evaluated for distribution normality using the
Kolmogorov-Smirnov/Shapiro-Wilk's test and independent student's t-test will be used to
compare normally distributed variables between groups. To compare categorical variables
chi-square or Fisher's exact test will be used. QT and QTc intervals within groups will be
investigated with repeated measures analysis of variance and post hoc multiple comparisons
will be performed by Bonferroni test. Sample size calculation was based on QTc interval.
Based on a previous study, QTc interval was found 397.3±27.4 msec after spinal anesthesia in
non-geriatric patients. Power analysis with α = 0.05 and β = 0.2 to detect an increase of at
least 20 msec in QTc interval revealed that a min of 28 patients should be included in each
group. A p value < 0.05 was considered to show a statistically significant result.
