Hyperosmolar Saline Irrigation Fluid in Arthroscopic Knee Surgery

Study Overview
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Brief Summary
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An isotonic solution, such as saline (0.9%, 300mOsm/L) or lactated ringer's (273 mOsm/L), is commonly used and safely proven for joint irrigation during arthroscopy. Arthroscopic fluid is usually pressurized to enable visualization through dilation of the joint or bursa and prevent bleeding from the microvasculature. It has been recommended that this pressure be maintained at 49mmHg or less below the systolic blood pressure to preserve the clarity of view. The combination of large amounts of pressurized irrigation solution and lengthy arthroscopic procedures may cause substantial tissue fluid retention. Thus, extravasation of irrigation fluid into the periarticular tissues is inevitable and may create technical difficulties as well as patient morbidity and complications. Previous investigators have reported complications including tracheal obstruction, post-operative airway edema and compromise leading to prolonged intubation, excess weight gain, neurologic injuries, skin necrosis, and fluid overload associated with excessive fluid extravasation and tissue retention. Furthermore, it has been shown that fluid accumulated during the operation is slowly released back into the systemic circulation. Although there is not a rapid change in circulating volume, there may be implications for elderly patients and those with multiple comorbidities during prolonged arthroscopic surgery. Therefore the investigators seek to determine if a hyperosmolar solution, similar to what is used in head trauma patients, can reduce the degree of fluid extravasation in knee arthroscopy. The investigators also seek to determine if a hyperosmolar solution has any effect on post-operative knee pain compared to the standard isotonic solution. The third objective is to determine if a hyperosmolar solution has any effect on post-operative pain medicine consumption compared to the standard isotonic solution.

Official Title
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Safety and Efficacy of Hyperosmolar Saline Irrigation Fluid in Arthroscopic Knee Surgery

Conditions
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Arthroscopic Knee Surgery

Intervention / Treatment
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* Drug: Hyperosmolar Saline
* Drug: Normal saline


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients (18 years of age or greater) undergoing arthroscopic knee surgery who are willing and able to consent. Exclusion Criteria: Current pregnancy or breastfeeding Unable to give consent Prisoner Mentally Disabled

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Hyperosmolar Saline<br>The hyperosmolar solution will be created by adding 120cc of 23.4% NS solution to a 3L bag of LR. | Drug: Hyperosmolar Saline<br>* The hyperosmolar solution will be created by adding 120cc of 23.4% NS solution to a 3L bag of LR.<br>|
| Placebo Comparator: Normal Saline<br>Lactate Ringer's (LR, 273mOsm/L) is commonly used at our facility as our isotonic standard irrigation solution and will serve as the control to be evaluated against a hyperosmolar (1.9%, 600mOsm) solution. | Drug: Normal saline<br>* Lactate Ringer's (LR, 273mOsm/L)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fluid Extravasation | To determine if a hyperosmolar solution, similar to what is used in head trauma patients, can change the degree of fluid extravasation in knee arthroscopy. | Immediately Postoperatively | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postoperative Pain | To determine if a hyperosmolar solution has any effect on post-operative knee pain (Visual Analogue Scale; 0-10; 0= no pain; 10= worst pain imaginable) compared to the standard isotonic solution. | Post-operative Days 1, 2 and 3 | 
| Opioid Consumption | To determine if a hyperosmolar solution has any effect on post-operative pain medicine consumption compared to the standard isotonic solution. | Postoperative Days 1, 2 and 3. |