Neuraxial Anaesthesia: Does BMI Relate to Ease of Neuraxial Anaesthesia?

October 22, 2017 updated by: Moninne Creaney, National Maternity Hospital, Ireland

Neuraxial Anaesthesia: Does BMI Relate to Palpability of Bony Landmarks and Are Standard Needles a Suitable First Choice in Patients With BMI>30kg/m2

Neuraxial anaesthesia can be more difficult and associated with more complications if the patient's bony landmarks are difficult to palpate. They are more likely to be difficult to palpate if a patient has a high Body Mass Index (BMI), (>30kg/m2). The depth that the spinal or epidural needle must be inserted is usually longer in these patients with high BMIs. We wish to palpate the backs of at least 100 such patients to see how many of them have impalpable bony landmarks. We then wish to use ultrasound to measure the distance from skin to the posterior epidural complex to discover if this length is longer than the standard needle length. If it is longer in the majority of people we study, we will recommend changing standard practice to start using a longer needle for all first attempts at neuraxial anaesthesia in this patient population.

Study Overview

Detailed Description

Complications rates including failure are higher in obese patients undergoing anaesthesia procedures. Anaesthetists have adopted the use of ultrasound to assist in overcoming these difficulties. Neuraxial ultrasound is proving to be beneficial in those patients in whom identification of interspinous spaces is difficult and most of these patients are obese.

In our institution, there is a 'standard practice' for neuraxial procedures, with a 'standard' needle used for first attempts (Whitacre 25G 90mm for spinal, Tuohy 18G 80mm for epidural). If the operator has not reached the desired space (spinal or epidural) with the needle inserted to 8cm, a longer needle is then considered for further attempts. This exposes the patient to at least one extra neuraxial needle insertion. Studies have shown that increased needle insertions and redirections are associated with increased complications.

We hypothesised that a large number of patients with BMI>30kg/m2 would have a depth of spinal/epidural space that is greater than the length of the 'standard' needle used. Therefore we suggest that practice should change to use the longer needle or a combined spinal-epidural on the first attempt in these patients.

To test our hypothesis, we will assess the ease of palpation of the following anatomical landmarks: anterior and posterior iliac crests; lumbar spinous processes; scapulae; and sacral cornua. We will then perform neuraxial sonography of the lumbar spine, measuring depth to epidural space. Finally we will measure waist circumference in those patients with BMI <30kg/m2.

Study Type

Observational

Enrollment (Anticipated)

100

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

16 years and older (Child, Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Female

Sampling Method

Non-Probability Sample

Study Population

Obstetric patients with BMI >30kg/m2, presenting in a non-emergency situation.

Description

Inclusion Criteria:

  • Recorded BMI >30kg/m2; ability to give consent; non-emergency cases.

Exclusion Criteria:

  • Previous metal work to lumbar spine.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Palpability of bony landmarks for neuraxial anaesthesia
Time Frame: 4 months
The percentage of patients with BMI>30kg/m2 who have difficult or impalpable bony landmarks including: lumbar spinous processes; anterior and posterior iliac spines; scapulae; and sacral cornua.
4 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Ultrasonographic distance from skin to posterior epidural complex
Time Frame: 4 months
To use sonography to measure the distance from skin to the dural complex in these patients and quantify the percentage whose distance is greater than the length of the standard needle.
4 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Study Director: Kevin McKeating, National Maternity Hospital, Ireland

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Anticipated)

October 23, 2017

Primary Completion (Anticipated)

January 9, 2018

Study Completion (Anticipated)

January 9, 2018

Study Registration Dates

First Submitted

October 17, 2017

First Submitted That Met QC Criteria

October 17, 2017

First Posted (Actual)

October 20, 2017

Study Record Updates

Last Update Posted (Actual)

October 24, 2017

Last Update Submitted That Met QC Criteria

October 22, 2017

Last Verified

October 1, 2017

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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