Clinical Trial Details
— Status: Active, not recruiting
Administrative data
| NCT number |
NCT04038476 |
| Other study ID # |
TCM1 |
| Secondary ID |
|
| Status |
Active, not recruiting |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
August 20, 2019 |
| Est. completion date |
November 1, 2024 |
Study information
| Verified date |
February 2024 |
| Source |
University of Ulm |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Complex procedures for treatment of cardiac arrhythmias are usually performed under deep
sedation, since a quiet position of the patient is usually required over several hours and a
significant risk of injury is caused by unconsciously movements of the patient. The sedative
medication inhibits respiration. This can result in an increase of CO2-levels or a reduction
oxygen-levels in the blood. Therefore, oxygen saturation (finger clip) is monitored
continuously and the CO2-levels in the blood are evaluated every half hour. The study aims to
evaluate, whether additional continuous CO2 measurement (transcutaneous CO2 monitoring) has a
safety benefit for patients in sedation. Patients are randomly divided into two groups. The
first group receives the previous standard monitoring and the second group additionally
receives the transcutaneous CO2 measurement. After completion of the procedure, all
study-relevant parameters are collected. Finally, the investigators examine whether oxygen
saturation decreases or CO2-level increases could be prevented by a continuous,
transcutaneous CO2 measurement.
Description:
Complex catheter ablations for treatment of supraventricular and ventricular tachycardias are
performed under moderate to deep sedation.
These interventions include electrophysiological examinations such as cryo-pulmonary vein
isolation as well as complex radiofrequency ablation using a 3D mapping system. In order to
avoid complications and to achieve a successful ablation result, a quiet position of the
patient should be ensured during the examination, which usually lasts several hours. Specific
reasons for the need for sedation include:
1. Femoral access The access is, in most cases, the right femoral vein. By transseptal
puncture of the atrial septum, the catheters are inserted into the left atrium, the most
common target structure of the above mentioned procedures. In order to insert the
catheter safely into the left atrium, the path from the right groin to the left atrium
is secured by a guide rail, a so-called sheath. Due to this relatively rigid guide rail,
unconsciously movements of the patient should be avoided during the examination.
2. 3D mapping system The 3D mapping system is used to create an individual, virtual,
electro-anatomical map ("map of the structure and electrical activity of the heart") of
the left atrium of the patient. The prerequisite for a millimeter accurate determination
of the catheter position by means of magnetic fields is the patient's quiet position.
Already deep breaths can endanger the catheter stability and thus the ablation result.
By movements of the patient there is also the risk that the virtual 3D map no longer
matches the real anatomy, this results in an increased risk of perforation in the left
heart with the result of a pericardial effusion or tamponade.
3. Patient positioning The patient has to lie flat and quiet during the procedure. Keeping
this position presents a challenge even for younger patients and short examination times
and is therefore impractical for the patient for several hours for reasons of comfort.
The sedation usually consists of a combination of midazolam and propofol. At the beginning of
the study, a midazolam bolus is administered and a low-dose propofol perfusor is started,
which is increased during the course until an optimal sedation depth is reached. During
ablation, opiates are also added for analgesia, depending on the procedure, consisting of
fentanyl single doses or continuous administration of remifentanil with perfusor.
The sedation depth is primarily controlled clinically. The above-mentioned substances all
have a respiratory depressive effect and can cause respiratory complications, in the sense of
hypercapnia or hypoxia. Therefore, standard monitoring involves the continuous measurement of
oxygen saturation by means of pulse oximetry (spO2) as well as the half-hourly analysis of a
venous blood gas analysis to evaluate the pH and to monitor the carbon dioxide partial
pressure (pCO2). For interventions in the left atrium there is also the possibility of an
arterial blood gas analysis from the left atrium or, if present, arterial blood gas analysis
from an arterial sheath. If abnormalities occur in the blood gas analysis, the depth of
sedation is adjusted accordingly or the dosage of the various components of the sedation is
adapted. In addition, there is a continuous heart rate measurement and regular non-invasive
blood pressure measurements. The nurse, assisting the sedation, also provides a dedicated
sedation protocol, with explanations of any change in sedation management during the
procedure.
In the electrophysiology laboratory of the ulm university hospital is the option of
continuous, transcutaneous CO2 monitoring using TCM 400 (Radiometer). For this purpose, an
adhesive electrode (Severinghaus electrode) is attached to the forehead of the patient.
Hereby, the measurement of the O2 and CO2 partial pressure in the underlying tissue can take
place and with good blood flow, this value approaches the invasively gained gas values. This
method ensures a continuous, non-invasive CO2 measurement. The collected parameters are
stored by the TCM 400 device in an Excel spreadsheet and can be exported and analyzed after
the procedure. The method was already used during complex catheter ablation as part of a
small observational study, but does not yet count as standard monitoring.
So far, it is unclear to what extent a continuous, transcutaneous CO2 monitoring can prevent
sedation-associated complications. The aim of this research project is the prospective,
randomized analysis of the benefits of continuous, transcutaneous CO2 monitoring + standard
monitoring in comparison to the previous standard monitoring. In particular, it should be
investigated to what extent sedation-associated complications, such as oxygen saturation
decreases, hypercapnia and respiratory acidosis can be prevented by continuous,
transcutaneous CO2 monitoring.
