Effect of Infusion Warming on Mannitol Infusion Pain in Patients With Acute Ocular Hypertension

Effect of Intravenous Infusion Warming on Pain, Comfort, Phlebitis, and Intraocular Pressure Outcomes During Mannitol Infusion in Patients With Acute Ocular Hypertension: A Randomized Controlled Study

Acute ocular hypertension is a common ophthalmic emergency that often requires rapid reduction of intraocular pressure. Intravenous mannitol is widely used for this purpose, but infusion-related pain and local venous irritation may reduce patient comfort, interfere with infusion speed, and affect treatment experience. This randomized controlled study aims to evaluate whether use of an infusion warming device during intravenous mannitol administration can reduce infusion-related pain, improve patient comfort, decrease local infusion-related complications, and improve infusion efficiency and short-term intraocular pressure outcomes in patients with acute ocular hypertension.

Participants with acute ocular hypertension who required intravenous mannitol treatment were randomly assigned to either a warming group or a non-warming group. In the warming group, mannitol was administered using an infusion warming device; in the non-warming group, mannitol was administered according to routine practice without warming. Outcomes included peak pain score during infusion, comfort score, infusion rate, infusion duration, local infusion-related adverse reactions, and intraocular pressure change after treatment.

Study Overview

• Status: Completed
• Conditions: Primary Angle-Closure Glaucoma; Acute Ocular Hypertension Glaucoma; Intraocular Hypertension
• Intervention / Treatment: Device: Infusion Warming Device; Other: Routine Non-Warmed Mannitol Infusion

Detailed Description

Acute ocular hypertension requires timely reduction of intraocular pressure to relieve symptoms and reduce the risk of optic nerve damage. Intravenous mannitol is commonly used in ophthalmic emergency care because of its rapid osmotic effect. However, mannitol infusion may cause infusion-related pain, discomfort, slowing or interruption of infusion, and local venous complications such as irritation and phlebitis. These problems may affect both patient experience and treatment efficiency.

Warming of intravenous fluids has been used in clinical practice to reduce discomfort associated with infusion of hyperosmotic or irritating solutions. In this study, an infusion warming device was applied during intravenous mannitol administration to examine whether warming could improve the tolerability and clinical performance of mannitol infusion in patients with acute ocular hypertension.

Eligible patients requiring intravenous mannitol treatment were assigned to either a warming group or a non-warming group. In the warming group, mannitol was administered through an infusion warming device according to the study protocol. In the non-warming group, mannitol was infused without warming according to routine clinical practice. Patient-reported outcomes and clinical outcomes were assessed during and shortly after infusion.

The main objective of the study was to compare infusion-related pain between the two groups. Additional objectives were to compare comfort, infusion efficiency, local infusion-related complications, and short-term intraocular pressure response after treatment. The study was conducted at a tertiary ophthalmic center in China.

• Study Type: Interventional
• Enrollment (Actual): 142
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Guangdong
    • Shantou, Guangdong, China, 515041
      • Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients with acute ocular hypertension requiring intravenous mannitol treatment in the ophthalmology setting
• Age 18 years or older
• Conscious and able to communicate pain and comfort during infusion
• Able to provide informed consent personally or via a legally authorized representative when appropriate
• Able to complete study-related assessments during and shortly after mannitol infusion

Exclusion Criteria:

• Patients who did not require intravenous mannitol treatment
• Known contraindication to intravenous mannitol treatment according to routine clinical practice
• Patients receiving infusion of heat-sensitive fluids or medications for which infusion warming was not appropriate
• Severe cognitive impairment, communication difficulty, or other conditions preventing reliable assessment of pain or comfort
• Failure to complete key study outcome assessments
• Refusal to participate in the study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Warming Group; Participants received intravenous mannitol infusion using an infusion warming device during treatment for acute ocular hypertension.	Device: Infusion Warming Device; An infusion warming device was used during intravenous mannitol administration to warm the infused fluid according to the study protocol.
Active Comparator: Non-Warming Group; Participants received routine intravenous mannitol infusion without use of an infusion warming device during treatment for acute ocular hypertension.	Other: Routine Non-Warmed Mannitol Infusion; Intravenous mannitol was administered according to routine clinical practice without infusion warming.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Peak pain score during infusion measured by the 11-point Numeric Rating Scale (NRS)	Peak infusion-related pain during intravenous mannitol administration, assessed using the 11-point Numeric Rating Scale (NRS). Scores range from 0 to 10, where 0 indicates no pain and 10 indicates the worst imaginable pain. Higher scores indicate worse pain.	During infusion, up to approximately 45 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Comfort during infusion measured by a 10-point Visual Analogue Scale (VAS)	Patient-reported comfort during intravenous mannitol administration, assessed using a 10-point Visual Analogue Scale (VAS). Scores range from 0 to 10, where 0 indicates the lowest comfort and 10 indicates the highest comfort. Higher scores indicate better comfort.	During infusion, up to approximately 45 minutes
Maximum infusion rate (drops/minute)	Maximum achievable intravenous infusion rate during mannitol administration, recorded in drops per minute. Higher values indicate faster infusion delivery.	During infusion, up to approximately 45 minutes
Total infusion duration (minutes)	Total duration of intravenous mannitol infusion, measured in minutes from the start to the completion of the full 250 mL infusion. Lower values indicate shorter infusion duration.	From infusion start to completion of the full 250 mL infusion, up to approximately 45 minutes
Intraocular pressure measured by iCare rebound tonometry at 30 minutes after infusion	Intraocular pressure measured using an iCare rebound tonometer. Results are reported in mmHg. Lower values indicate lower intraocular pressure.	30 minutes after completion of the full 250 mL infusion
Change in intraocular pressure measured by iCare rebound tonometry	Change in intraocular pressure from pre-infusion measurement to the measurement obtained 30 minutes after completion of the full 250 mL infusion, assessed using an iCare rebound tonometer and reported in mmHg. Higher positive values indicate greater reduction in intraocular pressure.	From pre-infusion baseline to 30 minutes after completion of the full 250 mL infusion
Request for slowing or temporary interruption of infusion due to infusion-related discomfort/pain	Whether the participant requested slowing or temporary interruption of the infusion because of infusion-related discomfort or pain. Reported as yes/no.	During infusion, up to approximately 45 minutes
Pain affecting mood or rest	Whether infusion-related pain affected participant mood or rest during treatment. Reported as yes/no.	During infusion, up to approximately 45 minutes
Grade I phlebitis assessed by clinical observation	Occurrence of infusion-related phlebitis assessed clinically by the nursing team according to local routine practice. Reported as yes/no.	During infusion and immediately after completion of infusion, up to approximately 1 hour
Local redness, swelling, or induration assessed by clinical observation	Occurrence of local infusion-site redness, swelling, or induration assessed clinically by the nursing team. Reported as yes/no.	During infusion and immediately after completion of infusion, up to approximately 1 hour

Collaborators and Investigators

• Sponsor: Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong
• Investigators: Principal Investigator: Laiwen Lv, Master, Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong

Publications and helpful links

General Publications

• Lam DS, Chua JK, Tham CC, Lai JS. Efficacy and safety of immediate anterior chamber paracentesis in the treatment of acute primary angle-closure glaucoma: a pilot study. Ophthalmology. 2002 Jan;109(1):64-70. doi: 10.1016/s0161-6420(01)00857-0.
• Lam DS, Lai JS, Tham CC, Chua JK, Poon AS. Argon laser peripheral iridoplasty versus conventional systemic medical therapy in treatment of acute primary angle-closure glaucoma : a prospective, randomized, controlled trial. Ophthalmology. 2002 Sep;109(9):1591-6. doi: 10.1016/s0161-6420(02)01158-2.
• Marsh N, Larsen EN, Ullman AJ, Mihala G, Cooke M, Chopra V, Ray-Barruel G, Rickard CM. Peripheral intravenous catheter infection and failure: A systematic review and meta-analysis. Int J Nurs Stud. 2024 Mar;151:104673. doi: 10.1016/j.ijnurstu.2023.104673. Epub 2023 Dec 9.
• Wang W. Tolerability of hypertonic injectables. Int J Pharm. 2015 Jul 25;490(1-2):308-15. doi: 10.1016/j.ijpharm.2015.05.069. Epub 2015 May 29.
• Guanche-Sicilia A, Sanchez-Gomez MB, Castro-Peraza ME, Rodriguez-Gomez JA, Gomez-Salgado J, Duarte-Climents G. Prevention and Treatment of Phlebitis Secondary to the Insertion of a Peripheral Venous Catheter: A Scoping Review from a Nursing Perspective. Healthcare (Basel). 2021 May 19;9(5):611. doi: 10.3390/healthcare9050611.
• Liang Z, Li H, Hou X, Yang K, Lv K, Ma Y, Lu Y, Wu K, Wu H. Prospective study on the role of preoperative mannitol in capsulorhexis and reducing intraoperative complications in primary angle-closure disease surgery. J Int Med Res. 2025 Jan;53(1):3000605241310106. doi: 10.1177/03000605241310106.

Study record dates

Study Major Dates

• Study Start (Actual): January 9, 2025
• Primary Completion (Actual): July 27, 2025
• Study Completion (Actual): July 27, 2025

Study Registration Dates

• First Submitted: March 17, 2026
• First Submitted That Met QC Criteria: March 21, 2026
• First Posted (Actual): March 27, 2026

Study Record Updates

• Last Update Posted (Actual): March 27, 2026
• Last Update Submitted That Met QC Criteria: March 21, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Intraocular Pressure; Ocular Hypertension; Intravenous Infusion; Mannitol Infusion Warming; Infusion Pain; Ophthalmic Nursing
• Additional Relevant MeSH Terms: Eye Diseases; Glaucoma; Ocular Hypertension; Glaucoma, Angle-Closure
• Other Study ID Numbers: EC 20240924(7)-P07

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: No individual participant data are planned to be shared. The study investigators do not plan to make de-identified individual-level data publicly available.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No