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Pain Pumps to the Rescue
Adding continuous nerve blocks to your post-op pain management protocol can get your patients walking down the road to recovery sooner.
Dori Kerner, Kathy Hughes, Kathy Hughes
Publish Date: November 4, 2008   |  Tags:   Anesthesia

Our mission: To discharge total-knee patients to home instead of to a rehabilitation facility. The result: Patients that often lost days of recovery from such opioid-induced side effects as nausea, confusion and low energy levels are now walking down the road to recovery sooner and with more confidence. Secret to our success: Using pain pumps to administer continuous femoral nerve blocks.

None of this was as easy as those three sentences make it sound. Yes, continuous ropivacaine boluses let patients ambulate sooner, which decreases their length of stay, letting us discharge them to home after a few days instead of to a rehabilitation facility. But too much ropivacaine causes knees to buckle and makes patients hesitant or unable to get out of bed after surgery. And incorporating pain pumps to our armamentarium meant we had to modify our post-op pain management protocol for these patients. Here's how we did it.

1. The way we were
Let's first look back at how we got started on the road to continuous nerve blocks. Our anesthesia providers would administer single shots of ropivacaine around the femoral nerve when total-knee patients reached the PACU. The providers would then deliver single boluses every 24 hours for up to three days following surgery. While largely effective, the single-shot blocks weren't without issues. Patients' pain sensations were reduced, but we noticed a high incidence of knee buckling caused by inhibited motor function of the quadriceps muscle. The risk of falling concerned patients, who didn't trust the stability of their freshly replaced joints, as well as the nurses and physical therapists who had to help them walk after surgery. We were making progress in post-op pain management, but we still had obstacles to overcome before discharging patients to home.

2. Finding the right ropivacaine dose
An 8ml/hr dose of ropivacaine to the femoral nerve reduced post-op pain, but didn't solve the knee-buckling issue. We then dropped the ropivacaine bolus to 4ml/hr, discovered it was too low and settled on a 6ml/hr dose. That amount provides a nice balance: It controls patients' pain with minimal narcotic use, reduces knee buckling and gives patients the confidence they need to begin ambulating soon after surgery. That confidence trickled down to our physical therapists and nurses, who had tired of putting themselves at risk while supporting woozy and wobbly patients.

3. The patient's role
Hospitalized patients also have the option to self-administer an additional 2ml bolus of ropivacaine every 15 minutes for controlling breakthrough pain. In addition, our anesthesiologists prescribe IV ketorolac (Toradol) in conjunction with PO narcotics to manage pain in the back of the knee, where pain pumps are largely ineffective. Ketorolac is an anti-inflammatory that works well when used in conjunction with PO pain meds; we give a loading 30mg dose followed by half-doses as needed for up to 48 hours.

4. Convenience counts
A button on our pumps labeled "push" provides an obvious cue to patients when they need to deliver additional medication boluses. An LED screen displays a 15-minute timer that lets patients know how long they have to wait before the pump allows another self-administered dose (the pump won't administer more than one bolus during each 15-minute window — set by our staff — no matter how often patients push the delivery button).

Ease of portability is important. Pain pumps should be lightweight, attach easily to patients and not impede their movements during post-op ambulation. The devices we use are equipped with cloth straps that hang from patients' necks (see photo). That works well, but a Velcro belt with a fanny pack that holds the pain pump might work even better.

Disposable pumps should have adequate volume capacity — they typically hold about 400ml of medication — so they'll deliver full doses without staff having to open and refill the medication chamber. Pumps should have an easy-to-read display to alert staff and patients when the pump's close to empty.

The results
The first three months of using inpatient continuous nerve blocks were the most challenging, as frontline staff and anesthesia providers worked to develop pain-control protocols for patients with varying physiological makeups. It took the better part of a year before results matched our on-paper goals. When they did, post-op recovery improvements were dramatic. Before employing nerve blocks, 91 percent of our patients used PCA (patient-controlled analgesia) pumps to self-administer pain-fighting narcotics. After nearly a year spent enhancing the blocks' effectiveness, that rate dropped to 9 percent. Over the same span, we noticed a 15 percent drop (from 41 percent to 26 percent) in patients who experienced knee buckling. Average patient ambulation on the first day post-op improved from 2 feet to 20 feet.

The addition of pain pumps to our post-op pain management efforts coincided with the hospital's anesthesiologists honing their techniques for placing catheters around the femoral nerve. What they once did blindly, relying on feel to place the block, they now accomplish with a stimulating catheter tip and ultrasound guidance. The improved technology lets providers place more effective blocks.

We've also discovered that patients who had previous knee replacement surgery without continuous nerve blocks report dramatically better experiences after recovering from procedures with our new pain pump protocols. Patients like being able to self-medicate without asking a nurse for assistance.

It took a multidisciplinary approach to accomplish our goals. We'll continue to tweak our pain pump regimen, but for now we feel the devices have been an unqualified success in getting patients to ambulate and to return home sooner.

Pain Pump Roundup

B. Braun Medical
Curlin PainSmart IOD Pain Management System
(800) BBRAUN2
www.bbraunusa.com
List price: Not disclosed
FYI: This ambulatory electronic infusion system comes equipped with Information On Demand technology for PCA, PCEA and epidural therapies. It boasts a rapid priming feature and software that supports easy drug protocol downloading from PDA to pump. Built-in features include programmable medication limits and automatic verification and confirmation of dose changes before implementation, which the company says reduces the risk of programming errors.

Delphi Medical Systems
IVantage
(888) 526-1426
www.delphimedical.com
List price: $2,495
FYI: This 13-ounce pump is compatible with approved accessories such as belt clips, shoulder straps and fanny packs, making it easy for patients to wear during post-op ambulation. It has a 0.1ml/hr to 999ml/hr flow rate, multiple alarm capabilities and patient-controlled analgesia with reservoir volume, bolus on demand and a lockout safety feature.

I-Flow Corporation
ON-Q Pain Relief System
(800) 448-3569
www.iflo.com
List price: starting at $395
FYI: This portable balloon-like elastomeric pump automatically and continuously infuses a local anesthetic to the surgical site or adjacent nerves in the days following surgery. The medication is delivered through a catheter that evenly distributes medication only to the areas that need it, says I-Flow.

LMA North America
LMA Pain Care and e-PainCare Systems
(800) 788-7999
www.lmana.com
List price: Not disclosed
FYI: The family of Pain Care and e-PainCare systems offer quantifiable, mechanical pumps (bolus-only or continuous flow with bolus option) or an electronic, programmable and reusable pump providing an hourly bolus to match patients' post-op needs and preferences. Durable, trimmable catheters fit multiple surgical situations and provide adequate and local pain relief coverage without negative narcotic side effects, says the company.

Smiths Medical
CADD-Solis Ambulatory Infusion System
(800) 426-2448
www.cadd-solis.com
List price: $4,495
FYI: This new system features safety software, smart infusion and an intuitive color user interface to promote ease of use and patient safety. Its compact, lightweight design enables patient mobility. Features onscreen graphs, trend reports and a user audit trail.

Sorenson Medical
ambIT Infusion Pump
(877) 352-1888
www.sorensonmedical.com
List price: Not disclosed
FYI: This 6.4-ounce pump can be programmed to infuse between 0.1ml/hr and 20ml/hr, is equipped with an on-demand bolus option of 0ml to 20ml and a five-minute to 12-hour lockout. It attaches with a luer or spike connection to any size medication bag up to 1000ml. Reusable or single-use pump and medication bag fit into a compact belt pack worn by the patient.

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