A Comparison of CoolStick With Ethyl Chloride for the Assessment of Light Touch

NCT ID: NCT06596486

Last Updated: 2025-07-09

Basic Information

• Recruitment Status: RECRUITING
• Total Enrollment: 62 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2025-04-01
• Study Completion Date: 2025-12-01

Brief Summary

The main aim of this study is to compare CoolStick to ethyl chloride spray for the assessment of light touch following neuraxial anaesthesia for caesarean delivery.

Coolstick and ethyl chloride will also be compared for the assessment of cold sensation.

Participants will also be asked whether they experienced any intraoperative pain.

Detailed Description

In England, up to 35% of deliveries in 2022 were by caesarean section. Current guidelines from NICE recommend that regional anaesthesia is offered for caesarean section. Neuraxial anaesthesia is considered to carry less risk of morbidity than general anaesthesia for both mother and neonate and is performed for approximately 92% of caesarean sections. To ensure the comfort of the mother, and to avoid intraoperative pain that could lead to general anaesthesia conversion, the neuraxial block is tested prior to commencing surgery. In the United Kingdom, the Royal College of Anaesthetists recommend that less than 1% of elective caesarean sections started under regional anaesthesia are converted to general anaesthesia.

Surveys of UK anaesthetists have found a wide range of practices when assessing neuraxial block, including the testing of light touch, temperature, pain and motor block. In a survey of UK anaesthetists, cold has been shown to be the most widely used modality for testing with 92% of respondents testing this modality. This was followed by touch, which 60% of respondents tested for. Recent consensus guidance from the Obstetric Anaesthetists' Association has recommended light touch as the primary testing modality for neuraxial anaesthesia for caesarean section, aiming for a sensory block to the T5 level or above. A second testing modality is recommended in cases where there is doubt over the light touch assessment. In practice, many anaesthetists will consider anaesthesia to be adequate when block to light touch is demonstrated to the T5 level or above and cold to the T4 level or above.

Ethyl chloride spray is the most common piece of equipment for used for testing in the UK. It has been shown that ethyl chloride spray can be used for the assessment of light touch and is equivalent to established methods when assessing adequacy of the block for surgery. However, ethyl chloride has disadvantages: skin irritation and allergic reactions sometimes occur; and containers are expensive, require replacing and carry a carbon footprint. The spray also remains in the atmosphere for up to two months and this can have a deleterious effect on the environment.

Cotton wool has been shown to be as effective at testing light touch when compared to more expensive methods. However, it is not necessarily practical to have multiple pieces of equipment required to assess different block modalities. Given that ethyl chloride is commonly used to test both modalities, a more sustainable and cost-effective approach to testing both light touch and cold would be ideal.

Theophany Limited recently developed the CoolStick for assessment of block height to cold. The CoolStick consists of a stainless-steel head and a plastic handle. It is kept in the fridge before use and is cleaned with an antibacterial wipe between patients. The CoolStick maintains a temperature adequate for cold assessment for up to 10 minutes in ambient theatre temperature and should be kept refrigerated for at least 40 minutes prior to use. It appears to be a more sustainable and cost-effective alternative to ethyl chloride spray; however, there are no studies that demonstrate its clinical application in this setting.

The primary aim of this study is to compare Coolstick with ethyl chloride spray for the assessment of light touch, with the secondary aim of comparing CoolStick to ethyl chloride for the assessment of cold.

Conditions

Anesthesia

Study Design

• Observational Model Type: CASE_ONLY
• Study Time Perspective: PROSPECTIVE

Study Groups

All participants

All participants will receive standard care with the addition of extra assessment of block from neuraxial anaesthesia

CoolStick

Intervention Type: OTHER

Assessment of block using CoolStick.

Ethyl Chloride

Intervention Type: OTHER

Assessment of block using ethyl chloride spray

Question

Intervention Type: OTHER

Participant will be asked if they felt pain or not.

Interventions

CoolStick

Assessment of block using CoolStick.

Intervention Type: OTHER

Ethyl Chloride

Assessment of block using ethyl chloride spray

Intervention Type: OTHER

Question

Participant will be asked if they felt pain or not.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Pregnant patients presenting for elective caesarean section under spinal or combined spinal-epidural anaesthesia.

Exclusion Criteria

• < 18 years old
• Unwilling or unable to give informed consent
• Inability to understand written and/or verbal English
• Allergy to stainless steel
• Allergy to ethyl chloride spray

• Minimum Eligible Age: 18 Years
• Eligible Sex: FEMALE
• Accepts Healthy Volunteers: No

Sponsors

Barts & The London NHS Trust

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Matthew Wikner

Role: STUDY_CHAIR

Barts & The London NHS Trust

Locations

Newham University Hospital

London, , United Kingdom

Site Status: RECRUITING

The Royal London Hospital

London, , United Kingdom

Site Status: RECRUITING

Whipps Cross University Hospital

London, , United Kingdom

Site Status: RECRUITING

Countries

United Kingdom

Central Contacts

Simon Apps

Role: CONTACT

simon.apps@nhs.net

07732888187

Facility Contacts

Matthew Wikner

Role: primary

Matthew Wikner

Role: primary

Matthew Wikner

Role: primary

Other Identifiers

331686

Identifier Type: -

Identifier Source: org_study_id