Music Distraction and Its Influence on Anesthetic Requirements During Elective Knee Surgery

Prior to surgery, patient participants will receive a combined spinal-epidural per VCU total joint protocol; the following steps are considered standard of care and not considered study procedures. The combined spinal-epidural procedure creates complete numbness below the abdomen down to the feet, which negates the need for general anesthesia. For patient comfort during the combined-spinal epidural procedure, a one-time dose of 2 milligrams of intravenous midazolam will be given; this dose is adequate for reducing anxiety while allowing the patient to maintain conversation with health care providers if necessary. The standard intrathecal dose for total knee replacement at our institution is 15 mg bupivacaine and 0.2 mg preservative-free morphine; this dose will provide complete numbness to the lower extremities for approximately 3-6 hours. After this dose is administered, the patient will then be positioned appropriately in the operating room and vital signs will monitored per standard protocol.

Each patient participant will be randomized to one of two groups. Participants in the control group will receive noise-cancelling wireless headphones that will not play any noise throughout the procedure. Participants in the experimental group will receive the same noise-cancelling wireless headphones but will be permitted to listen to the music of their choice while in the operating room. Music will be provided via Spotify, which is an Internet streaming music service, and will be played through headphones; this way, no other individual in the operating room will be distracted or influenced by the patient's music selection. Participants will not be able to change the Spotify channel. We will be using the paid Spotify service with no commercials. If participants opt to have the music stopped, we will withdraw them from the study and continue standard of care. The participants will have the music playing for about two hours. If the participant has no music preference, the music will be chosen for them and it will be the same for all participants that have no preference. The volume will be adjusted in the operating room until the participant approves of the volume by saying "yes, the volume is good" or giving another verbal cue of approval.The music will continue playing until the surgical procedure is complete and the patient has reached the post-anesthesia recovery unit.

As stated previously, spinal anesthesia provides numbness that negates the need for general anesthesia, but patients often times need additional sedation, which will be defined as anesthesia medication that is used to treat patient anxiety and discomfort in the operating room. Patient participants in both groups will receive sedation via the same protocol, which is outlined below.

Sedation will only be given as needed per patient request; the patient will be given a noise-making device (such as a rubber duckie that makes sound when squeezed) that will inform the anesthesia provider that the patient is uncomfortable and needs some sedation. A weight based dose of 0.3 micrograms per kilogram of intravenous propofol will be given for each patient request. This dose is expected to provide amnesia or light sleep for a few minutes. For patient safety, if the patient requests sedation more than once within a two minute window, the anesthesia provider will not administer any more medication during this two minute period. Additionally, the anesthesia provider may withhold sedation if he or she determines with physical exam and hemodynamic monitors that the patient is already over-sedated.

After five propofol boluses have been given to a patient, a propofol continuous infusion will be initiated at 25mcg/kg/min. The patient may still request additional sedation with the request instrument if he or she is still conscious enough to do so. If the anesthesia provider has given more than five boluses even with the baseline propofol infusion, the infusion will be increased to 50mcg/kg/min. In the highly unlikely scenario that five additional boluses are required with a propofol infusion rate of 50 mcg/kg/min, the anesthesia providers and investigators will make a clinical decision as to what is the safest next step.

There may be scenarios that warrant conversion to general anesthesia. These scenarios include, but are not limited to, hemodynamic instability, regurgitation of gastric content, obtundation, excessive agitation, and inadequate spinal anesthesia. The decision to convert to the general anesthesia will be made by the anesthesiologist and anesthesia provider in the operating room; implementation of this study should not prevent or delay this decision if it is necessary.

Documentation will be completed by the anesthesia provider per standard protocol for electronic anesthesia charting at VCU. This will allow for data acquisition by the investigators through the anesthesiology printed record in Cerner.

Inclusion criteria

• undergoing a primary elective total knee replacement by Dr. Gregory Golladay (VCU surgeon and co-investigator for this research study)
• 18 years of age or older
• eligible for spinal anesthesia (which will be determined by the health care providers during the standard pre-surgery clinic visits)
• mentally capable of understanding instructions on how to request anesthesia medication
• mentally capable of understanding instructions on how to rate pain scores, anxiety level, and patient satisfaction

Exclusion criteria

• identified as a member of a regulated vulnerable population (one exception: limited English proficiency does not preclude them from this study; translation documents are available)
• ineligibility for spinal anesthesia (which will be determined by the health care providers during the standard pre-surgery clinic visits)
• morbid obesity, BMI greater than 40
• allergy to propofol, midazolam, or morphine
• pre-operative daily opioid consumption of more than 10 mg oxycodone every 6 hours
• hearing impaired individuals