Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT05693428 |
| Other study ID # |
1 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
January 22, 2022 |
| Est. completion date |
November 26, 2022 |
Study information
| Verified date |
January 2023 |
| Source |
Astana Medical University |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Abstract Cardiac surgery in adults is associated with the occurrence of post-operative
complications. Even minor complications can increase the cost of their treatment. Given the
potentially preventable nature of a number of these postoperative complications, preventive
methods should be used to improve outcomes after cardiac surgery. One of them, is the choice
of anaesthetic technique.
Objectives: To evaluate the effects of sevoflurane, isoflurane and propofol on blood oxygen
transport function and body energy expenditure during cardiac surgery in adults.
Materials and methods. A total of 90 patients were included in the study. All patients were
divided into 3 groups: 1- (n=30) included patients who were anesthetized with propofol. The
second group (n=30) consisted of patients who underwent sevoflurane inhalation anaesthesia.
Group 3 (n=30) was treated with isoflurane. All patients underwent coronary artery bypass
grafting under cardiopulmonary bypass.
Description:
Introduction Anaesthetic support for various types of cardiac surgery, such as coronary
artery bypass grafting (CABG), heart valve repair or replacement, ascending aorta surgery,
heart transplantation and surgical treatment of congenital heart disease, share many
principles. Indirect calorimetry can be an indicator of homeostatic changes during surgery.
Stress increases oxygen consumption (VO2) and during anaesthesia there is a decrease in VO2.
Cardiac surgery in adults is associated with the occurrence of postoperative complications
[1]. Even minor complications, can increase the cost of their treatment. Given the
potentially preventable nature of a number of these postoperative complications, preventive
methods should be used to improve outcomes after cardiac surgery. One of them, is the choice
of anaesthetic technique [2].
Tissues vary considerably in their sensitivity to hypoxia. Neurons tolerate hypoxia for only
a few minutes, whereas the smooth muscles of the bladder go several days without oxygen. This
has important implications for oxygen transport and monitoring of tissue hypoxia in patients.
The mechanisms controlling the distribution of oxygen in the body are not fully understood
(3). Increased oxygen extraction, the ratio of consumption to transport, has been associated
with poor outcome after surgery. The authors note [4] a -65 ml decrease in oxygen consumption
after general anaesthesia. Researchers [5,6] found that surgery and anaesthesia did not
significantly affect oxygen consumption and energy expenditure during anaesthesia. However,
Julia Jakobsson et al (2021) state that general anaesthesia reduced VO2 by approximately one
third in elderly patients undergoing major abdominal surgery. These changes require further
evaluation in relation to outcomes and surgery (7). Cerebral blood flow was reduced by 27.6%
and cerebral vascular resistance by 51% at moderate propofol concentrations. Brain oxygen
consumption was reduced by 18.2% [8]. Oxygen delivery (DO2) is an important marker of O2
transport than arterial blood oxygen saturation (SaO2). Anaesthetics (propofol or
sevoflurane) had no significant effect on DO2 . In addition, no correlation was found between
SaO2 and DO2. DO2 data may provide useful additional information about the patient's
condition, especially with low SaO2 [9]. A decrease in metabolic rate during anaesthesia has
been noted in patients with hypothermia, but this did not alter DO2. A significant decrease
in O2ER might be partly due to a shift to the left of the oxyhemoglobin dissociation curve,
as indicated by a decrease in P50 [10]. Oxygen consumption during general anaesthesia was
independent of the type of anaesthetics. General anaesthesia leads to a marked decrease in
oxygen consumption, but during recovery the O2 uptake can increase dramatically. Meperidine
can suppress and reduce postoperative VO2 to the level observed after TIA [11]. Indirect
calorimetry can be an indicator of homeostatic changes during surgery. Stress increases
oxygen consumption and during anaesthesia there is a decrease in VO2 due to lack of kinetic
energy as a cellular metabolic response to surgical trauma and anaesthesia. More research is
needed to find out which oxygen consumption measurement system is the most appropriate for
anaesthesia and what the VO2 limit values might be [12].
In view of the above opinion of the authors and the lack of studies that have shown the
effects of sevoflurane, isoflurane and propofol on energy expenditure, blood oxygen and
oxygen transport function, this needs to be further investigated.
Objectives: To evaluate the effects of sevoflurane, isoflurane and propofol on blood oxygen
transport function and body energy expenditure during cardiac surgery in adults.
Methods Study type: single-centre prospective randomised clinical trial. The study includes
data from 90 patients operated on at the Cardiosurgery Department of the RSE Medical Centre
Hospital of the President's Affairs Administration of the Republic of Kazakhstan. All
patients underwent coronary artery bypass grafting under cardiopulmonary bypass (CPB). This
research work was conducted between 2021 and 2022. To calculate the sample size, we used the
formula n=t2*D*N/confidence interval*N+t2*α, which will allow to identify the static
significance of the study.
This research was approved by the Local bioethical committee of Non-commercial joint-stock
company AMU №3 and written informed consent was obtained from all subjects.
All patients were divided into 3 groups: 1 (control group) (n=30) consisted of patients who
underwent anaesthesia with propofol (P). The second group (n=30) were patients who received
sevoflurane inhalation anaesthesia (S). Group 3 (n=30) with isoflurane (I).
The study was conducted in 5 stages:
1. determined the patient's baseline values before anaesthesia;
2. after tracheal intubation;
3. Before the CPB;
4. after the CPB;
5. The post-operative period. Before induction into anaesthesia, haemodynamic monitoring
with Nihon Kohden monitors (Japan) was initiated on admission to the operating theatre.
The right radial artery was catheterised for invasive systemic pressure monitoring and
arterial blood sampling, then a catheter was inserted into the central jugular vein
(under ultrasound machine control) and guided into the right atrium for mixed venous
blood sampling.
Cardiac stroke volume was determined by transthoracic echocardiography (CS=end diastolic
volume - end systolic volume). Cardiac output (CO=CS x heart rate), cardiac index (CI=CB/body
surface area) were determined. Blood oxygen content was determined using the formula CaO2
(arterial blood gas ABG) and CvO2 (central mixed venous BG) = [(1.34 × Hb × SO2) + (PO2 ×
0.031)] / 100, arteriovenous difference = CaO2-CvO2. Oxygen delivery was determined using the
formula (DO2 = CI* CaO2), oxygen consumption (VO2 = Cardiac index (CI)*AVR or VO2 = CB ×
(CaO2 - CvO2) ~ CB × Hb × 1.34 × (SaO2 - SvO2) / 100).
In the second stage, after tracheal intubation, indirect calorimetry was used to determine
VO2, energy expenditure during anaesthesia, using a "Spirometry" (Oxford, UK), which was
connected to an endotracheal tube and continuously showed oxygen demand and energy
expenditure. Additionally, cardiac output was determined using Fick's formula. In the third
and fourth stages of anaesthesia the same tests (cardiac output, cardiac index, consumption,
oxygen delivery and energy expenditure) were determined. In the last stage to assess the
pharmaco-efficiency of anaesthetics, the consumption of muscle relaxants and opioid
analgesics was calculated. The time of extubation and the time of transfer of the patient to
the specialist department were determined.
All patients were given the same type of premedication: 30-40 minutes before surgery, 0.3
mg/kg promedol was administered intramuscularly. Patients continued to take their usual
baseline drugs both before and on the day of surgery to prevent withdrawal syndrome and to
reduce the risk of myocardial ischaemia in the perioperative period.
All patients in both groups were given fentanyl in a dose of 5-7 µg/kg, ketamine 1.5-2 mg/kg,
and propofol 1-1.5 mg/kg intravenously fractionally. Pipecuronium bromide 0.04-0.07 mg/kg was
used as muscle relaxant in all patients. To maintain anaesthesia in Group 1 P, propofol was
used as an anaesthetic in a dose of 5-6 mg/kg/h intravenously on a perfusor (BBRAUN). In
Group 2, sevoflurane was used as an anaesthetic in a dose of - 1.7-1.9 MAC. In Group 3
isoflurane was used as anaesthetic. In all groups fentanyl 100 µg intravenously was
administered fractionally to increase heart rate and blood pressure, also pipecuronium
bromide 2 mg intravenously for muscle relaxation. During CPB in all patients in all groups,
propofol was used at a dose of 6 mg/kg/h intravenously via perfusion, analgesic regimen:
fentanyl 100 µg intravenously every 30 min; myorelaxant piperonium bromide 2 mg every 40-60
min. Norepinephrine solution was administered at a dose of 0.05 µg/kg/min intravenously on
perfusor after CPB in all patients at the same dosages in all groups.
Aim to use cardiotonic drugs:
1. in order to maintain mean arterial perfusion pressure (CPB causes cytokine storm and
vasodilation).
2. for inotropic support (for reperfusion syndrome, resulting in a lower ejection
fraction).
The depth of anaesthesia was monitored with a processed electroencephalogram, such as a BIS.
Statistical analysis was performed using IBM SPSS Statistics 20 package using one-factor
analysis of variance for independent samples and nonparametric Kraskel Wallis test. The
Kraskel-Wallis test was applied only to myorelaxant consumption, as the distribution was
non-normal on this parameter. A Pearson and Spearman correlation analysis was also performed
to determine the significance of the association between cardiac index and oxygen
consumption, as well as energy expenditure.
