None listed
Conditions
Brief summary
This study will test a new device which has the potential to measure how strong patient's hearts are beating. At present it is unknown how accurate this device is. This study will compare readings from this new device with readings taken from the usual method of measuring. The usual method is to insert a special IV line (a pulmonary artery catheter) through the neck passing through the blood vessels, past the heart and into the lungs to measure how strongly the heart is beating. This requires expertise and expensive equipment. Because it is inserted through the neck it can cause complications such as bleeding, infection or a collapsed lung. We will select 20 participants who are undergoing heart surgery at Auckland City Hospital who will be having a pulmonary artery catheter inserted as part of their standard care during their operation. The study will take place in the operating theatre once the participant has been anaesthetised and before the surgeons begin their work. We will attach all the usual monitors we would normally use for this type of surgery. We will then attach the new device, which is similar to a pulse oximeter finger probe. We then take a reading from the usual heart monitor (the pulmonary artery catheter) and at the same time we take a reading from the new device. We will administer some IV fluid (the standard fluid that we use for these operations) over 7 minutes. Two minutes later, we will repeat the readings. Once these readings are complete, the study has finished. The proposed surgery with then continue as normal. We will then compare all the readings from the new device and the pulmonary artery catheter to determine how accurate the new device is, and to see if it accurate distinguish those patients who will respond to an amount of IV fluid from those who will not.
Interventions
Following routine induction of anaesthesia, insertion of the usual monitoring devices (including a pulmonary artery catheter), the new device (which resembles a pulse oximeter finger probe) will be placed on one of the participant's fingers. A recording of baseline haemodynamic parameters will be made from the new device and from the pulmonary artery catheter (via the continuous thermodilution technique). Each device records automatically in an electronic manner. The pulmonary artery catheter is
Following routine induction of anaesthesia, insertion of the usual monitoring devices (including a pulmonary artery catheter), the new device (which resembles a pulse oximeter finger probe) will be placed on one of the participant's fingers. A recording of baseline haemodynamic parameters will be made from the new device and from the pulmonary artery catheter (via the continuous thermodilution technique). Each device records automatically in an electronic manner. The pulmonary artery catheter is highly invasive (it is a line inserted in the neck passing through the heart and into the pulmonary artery of the lungs) and carries a not insignificant risk of serious complications, whereas the new device is entirely non-invasive and measures stroke volume via the variable absorbance of infrared and near-infrared lights passed through a finger tip, which poses no risk to patients. Participants will then be given a fluid bolus (7mL/kg of PlasmaLyte 148) over 7 minutes. Patients would ordinary receive a similar amount of fluid prior to commencing cardiopulmonary bypass, but usually over a period of up to 45 minutes. Two minutes following completion of the fluid bolus, the same haemodynamic recordings will be made. The study is complete at this point. The new device will be removed and the surgical procedure will continue as planned.
Sponsors
Dr. Alan J. Broderick
Study design
Allocation
Non-randomised trial
Primary purpose
Diagnosis
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Patients due to undergo cardiac surgery. Pulmonary artery catheter required to be inserted prior to commencement of surgery.
Exclusion criteria
Patient refusal (or inability to provide full informed consent). Ejection fraction <30% (avoids potential difficulties with giving the fluid bolus). Cardiac arrhythmias present at induction. Known moderate (or worse) tricuspid regurgitation (makes thermodilution estimates of CO inaccurate). Known moderate (or worse) aortic regurgitation (previous studies using pulse contour analysis have excluded these – causes an abnormal pulse signal). Presence of an intra-aortic balloon counterpulsation device (cause an abnormal pulse signal, device may give inaccurate readings). Known haemoglobinopathy (novel device will not read correctly).
Outcome results
None listed