HypotensionDINOCSNCT02437799
Dicrotic Notch and Hypotension at Caesarean Under Spinal Anaesthesia
An observational study of Hypotension, run by Sheffield Teaching Hospitals NHS Foundation Trust at 1 site in United Kingdom.
Trial summary
BACKGROUND: Hypotension occurs commonly during spinal anaesthesia for caesarean section and may result in detrimental effects to the mother and foetus. A previous pilot study where images of the pulse oximeter waveform study were taken, found that the dicrotic wave moved away from the systolic wave during the onset of… Read more about this study
- Who is it for?
- Ages 18 to 50 years, women only
- Conditions the study is for
- Hypotension
- What is being tested?
- Dicrotic wave analysis
- How many people
- 20 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- Sep 2015to Dec 2015
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 50 years
- Women only
- No healthy volunteers
- Adult
Study population: Women undergoing planned caesarean section under spinal anaesthesia
Who may be able to join
- Patients with an uncomplicated pregnancy presenting for elective caesarean section under spinal anaesthesia where surgery and anaesthesia are anticipated to be uncomplicated.
Who cannot join
- Conditions which may impair the ability of the technology to read accurately such as:
- Reduced peripheral perfusion e.g. Raynaud's phenomenon
- Circulating pigments e.g. bilirubin
- Nail varnish that cannot be removed Diseases of pregnancy: e.g. pregnancy induced hypertension Significant co-existing maternal disease - e.g. congenital heart disease Inability to speak fluent English
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
Sheffield NHS Trust
Sheffield, South Yorkshire, S10 2JF
About this study
Official title: Analysis of Changes in the Pulse Oximeter Waveform and Blood Pressure During Spinal Anaesthesia for Caesarean Section: an Observational Study
BACKGROUND:
Hypotension occurs commonly during spinal anaesthesia for caesarean section and may result in detrimental effects to the mother and foetus. A previous pilot study where images of the pulse oximeter waveform study were taken, found that the dicrotic wave moved away from the systolic wave during the onset of hypotension.
Read more
AIMS:
The investigators wish to download electronic data which describe the pulse oximeter pulse wave to more accurately assess movement of the diastolic wave relative to the systolic wave during spinal anaesthesia for caesarean section.
METHODOLOGY:
20 women undergoing caesarean section under spinal anaesthesia will be recruited by informed consent for this observational study. Data downloaded from the pulse oximeter will be analysed to identify movement of the dicrotic wave relative to the systolic wave and this will be related to changes in blood pressure.
EXPECTED OUTCOMES:
The investigators will establish best way to analyse changes in the pulse oximeter waveform and the relationship between changes in pulse oximeter waveform morphology and the onset of hypotension during spinal anaesthesia for caesarean section.
IMPLICATIONS:
Analysis of movement of the dicrotic wave could be used to anticipate and thus avoid severe hypotension during spinal anaesthesia for caesarean section.
Read the detailed description
BACKGROUND:
When a baby is delivered by a surgical procedure (a caesarean section) the women will usually have a spinal anaesthetic. With a spinal anaesthetic local anaesthetic is injected into the spinal fluid to make the woman numb from her chest to her feet allowing her to be comfortable but awake during the birth. One of the common side effects of a spinal anaesthetic is that the woman's blood pressure may fall making her feel unwell and (rarely) causing stress to the unborn baby.
During a caesarean section the blood pressure is usually measured every few minutes using a cuff around the upper arm. However, the blood pressure may fall too quickly to be detected in a timely fashion by this intermittent means. One of the other monitors used in all cases is called a pulse oximeter. When this is attached to the patient's finger it detects the pulse rate and how much oxygen there is in the blood. The pulse oximeter also produces an image of the pulse wave in the finger. There is one pulse wave for every time the heart beats and it has two components. The main part of the wave (the systolic wave) is caused by the heart beat and the second part of the wave (the dicrotic wave) is a result of some of the energy from the heart beat bouncing back from blood vessels.
In a previous study we used a digital camera to take images of the pulse oximeter monitor screen so that we could record changes in the shape of the pulse wave. We found that as patients' blood pressure fell the dicrotic wave moved further away from the systolic wave. We now intend to down load the electronic data that make up the pulse oximeter waveform, so that we can analyse the changes that occur more accurately.
We believe that falling blood pressure may be detected earlier using analysis of movement of the dicrotic wave than by our standard monitoring. This is because currently blood pressure is measured intermittently whereas the pulse oximeter waveform is displayed continuously. Drugs could then be given promptly to stop the blood pressure from falling so low that the woman feels unwell or the unborn baby is affected.
AIMS:
Our aim is to observe changes in the position of the dicrotic wave during spinal anaesthesia for caesarean section and relate these to the occurrence of low blood pressure.
METHODOLOGY:
Following ethical approval 20 women undergoing caesarean section under spinal anaesthesia will be recruited by written informed consent. In theatre the electronic data which describe the pulse oximeter waveform will be downloaded by means of a data logger. In parallel, we will manually record the other perioperative data including the blood pressure. We will then use the data to establish the best way of accurately and reproducibly identifying the dicrotic wave when it moves in relation to the onset of low blood pressure. As this is an observational study, the management of the case will be at the discretion of the attending anaesthetist in discussion with the patient and will not be altered by inclusion in the study.
EXPECTED OUTCOMES:
- We will establish the best way to detect movement of the dicrotic wave.
- We will establish the temporal relationship between movement of the dicrotic wave and fall in blood pressure during spinal anaesthesia for caesarean section.
IMPLICATIONS:
Anaesthetists will be able to use movement of the dicrotic wave to anticipate and avert low blood pressure during spinal anaesthesia for caesarean section.
- Conditions
- Hypotension
- Being tested
- Dicrotic wave analysis
- Keywords
- Pulse oximeter, Caesarean section, hypotension, Spinal anaesthesia
- Medical subject headings
- Hypotension
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Dicrotic wave analysisOther
We will download data from the pulse oximeter that is being used to monitor the patient during their surgery.
| Study group | Role | What they receive |
|---|---|---|
| Caesarean section spinal anaesthesia | Dicrotic Wave analysis of pulse oximeter of Women undergoing planned caesarean section under spinal anaesthesia. Receives: Other: Dicrotic wave analysis |
What is being measured
The primary outcome is the main question the study is designed to answer.
1. To download electronic data which describe the pulse oximeter pulse wave to accurately assess movement of the diastolic wave relative to the systolic wave during spinal anaesthesia for caesarean section.
Data will be collected during planned caesarean section under spinal anaesthesia
Measured: Data will be downloaded for approximately 20 minutes
Secondary outcomes (3)
Time course of cardiovascular changes
- To clearly document the time-course of cardiovascular changes and hypotension during spinal for caesarean section
Measured: twenty minutes
Preliminary cardiovascular data
- To provide preliminary data to characterise cardiovascular changes during hypotension
Measured: twenty minutes
Vascular behaviour
- To characterise changes in vascular behaviour, and to determine their time course, before and after onset of hypotension and the given treatment.
Measured: twenty minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 May 2015 (estimated)
- Study startSep 2015
- Primary completionDec 2015
- Study completionDec 2015
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HypotensionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- Sheffield Teaching Hospitals NHS Foundation Trust
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- ian Wrench, MBChB,FRCA, Principal investigator, Sheffield Teaching Hospitals NHS Foundation Trust
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02437799
- Sponsor's protocol ID
- STH18900
- Acronym
- DINOCS
- Status last verified
- Oct 2016
- First submitted
- 1 Apr 2015
- Last updated
- 13 Oct 2016
- Results posted
- No
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 13 Oct 2016. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Analysis of Changes in the Pulse Oximeter Waveform and Blood Pressure During Spinal Anaesthesia for Caesarean Section: an Observational Study
- ClinicalTrials.gov ID
- NCT02437799
- Acronym / sponsor ID
- DINOCS / STH18900
- Conditions
- Hypotension
- Keywords
- Pulse oximeter, Caesarean section, hypotension, Spinal anaesthesia
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 20 participants (actual)
- Lead sponsor
- Sheffield Teaching Hospitals NHS Foundation TrustUniversity, hospital or other
- Study start
- Sep 2015
- Primary completion
- Dec 2015 (actual)
- Study completion
- Dec 2015 (actual)
- First posted
- 8 May 2015 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
BACKGROUND:
Hypotension occurs commonly during spinal anaesthesia for caesarean section and may result in detrimental effects to the mother and foetus. A previous pilot study where images of the pulse oximeter waveform study were taken, found that the dicrotic wave moved away from the systolic wave during the onset of hypotension.
AIMS:
The investigators wish to download electronic data which describe the pulse oximeter pulse wave to more accurately assess movement of the diastolic wave relative to the systolic wave during spinal anaesthesia for caesarean section.
METHODOLOGY:
20 women undergoing caesarean section under spinal anaesthesia will be recruited by informed consent for this observational study. Data downloaded from the pulse oximeter will be analysed to identify movement of the dicrotic wave relative to the systolic wave and this will be related to changes in blood pressure.
EXPECTED OUTCOMES:
The investigators will establish best way to analyse changes in the pulse oximeter waveform and the relationship between changes in pulse oximeter waveform morphology and the onset of hypotension during spinal anaesthesia for caesarean section.
IMPLICATIONS:
Analysis of movement of the dicrotic wave could be used to anticipate and thus avoid severe hypotension during spinal anaesthesia for caesarean section.
Detailed description
BACKGROUND:
When a baby is delivered by a surgical procedure (a caesarean section) the women will usually have a spinal anaesthetic. With a spinal anaesthetic local anaesthetic is injected into the spinal fluid to make the woman numb from her chest to her feet allowing her to be comfortable but awake during the birth. One of the common side effects of a spinal anaesthetic is that the woman's blood pressure may fall making her feel unwell and (rarely) causing stress to the unborn baby.
During a caesarean section the blood pressure is usually measured every few minutes using a cuff around the upper arm. However, the blood pressure may fall too quickly to be detected in a timely fashion by this intermittent means. One of the other monitors used in all cases is called a pulse oximeter. When this is attached to the patient's finger it detects the pulse rate and how much oxygen there is in the blood. The pulse oximeter also produces an image of the pulse wave in the finger. There is one pulse wave for every time the heart beats and it has two components. The main part of the wave (the systolic wave) is caused by the heart beat and the second part of the wave (the dicrotic wave) is a result of some of the energy from the heart beat bouncing back from blood vessels.
In a previous study we used a digital camera to take images of the pulse oximeter monitor screen so that we could record changes in the shape of the pulse wave. We found that as patients' blood pressure fell the dicrotic wave moved further away from the systolic wave. We now intend to down load the electronic data that make up the pulse oximeter waveform, so that we can analyse the changes that occur more accurately.
We believe that falling blood pressure may be detected earlier using analysis of movement of the dicrotic wave than by our standard monitoring. This is because currently blood pressure is measured intermittently whereas the pulse oximeter waveform is displayed continuously. Drugs could then be given promptly to stop the blood pressure from falling so low that the woman feels unwell or the unborn baby is affected.
AIMS:
Our aim is to observe changes in the position of the dicrotic wave during spinal anaesthesia for caesarean section and relate these to the occurrence of low blood pressure.
METHODOLOGY:
Following ethical approval 20 women undergoing caesarean section under spinal anaesthesia will be recruited by written informed consent. In theatre the electronic data which describe the pulse oximeter waveform will be downloaded by means of a data logger. In parallel, we will manually record the other perioperative data including the blood pressure. We will then use the data to establish the best way of accurately and reproducibly identifying the dicrotic wave when it moves in relation to the onset of low blood pressure. As this is an observational study, the management of the case will be at the discretion of the attending anaesthetist in discussion with the patient and will not be altered by inclusion in the study.
EXPECTED OUTCOMES:
- We will establish the best way to detect movement of the dicrotic wave.
- We will establish the temporal relationship between movement of the dicrotic wave and fall in blood pressure during spinal anaesthesia for caesarean section.
IMPLICATIONS:
Anaesthetists will be able to use movement of the dicrotic wave to anticipate and avert low blood pressure during spinal anaesthesia for caesarean section.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Caesarean section spinal anaesthesia | – | Other: Dicrotic wave analysisDicrotic Wave analysis of pulse oximeter of Women undergoing planned caesarean section under spinal anaesthesia. |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult
- Study population
- Women undergoing planned caesarean section under spinal anaesthesia
Key inclusion criteria (1 listed)
- Patients with an uncomplicated pregnancy presenting for elective caesarean section under spinal anaesthesia where surgery and anaesthesia are anticipated to be uncomplicated.
Key exclusion criteria (4 listed)
- Reduced peripheral perfusion e.g. Raynaud's phenomenon
- Circulating pigments e.g. bilirubin
- Nail varnish that cannot be removed Diseases of pregnancy: e.g. pregnancy induced hypertension Significant co-existing maternal disease - e.g. congenital heart disease Inability to speak fluent English
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Dicrotic wave analysisWe will download data from the pulse oximeter that is being used to monitor the patient during their surgery. | Other | Caesarean section spinal anaesthesia |
Primary outcome
1. To download electronic data which describe the pulse oximeter pulse wave to accurately assess movement of the diastolic wave relative to the systolic wave during spinal anaesthesia for caesarean section.
Time frame: Data will be downloaded for approximately 20 minutes
Data will be collected during planned caesarean section under spinal anaesthesia
3 secondary outcomes
Time course of cardiovascular changes
Time frame: twenty minutes
Preliminary cardiovascular data
Time frame: twenty minutes
Vascular behaviour
Time frame: twenty minutes
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Oct 2016.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
ian Wrench, MBChB,FRCA principal investigator
Sheffield Teaching Hospitals NHS Foundation Trust
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Hypotension, run by Sheffield Teaching Hospitals NHS Foundation Trust at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 13 Oct 2016. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
1. To download electronic data which describe the pulse oximeter pulse wave to accurately assess movement of the diastolic wave relative to the systolic wave during spinal anaesthesia for caesarean section. (time frame: Data will be downloaded for approximately 20 minutes). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 13 Oct 2016.