CHICAGO – Ketamine is a safe and simple alternative to epidural anesthesia for pain control in the setting of multiple rib fractures, investigators from the Jacobi Medical Center in the Bronx (N.Y.) concluded after reviewing their experience with the drug.
Epidural analgesia has been the standard for controlling pain after multiple rib fractures, but epidurals are sometimes contraindicated in trauma, especially with back and neck injuries. There’s also a bleeding risk, and the need for an on-call anesthesia team to place them, something not all hospitals have.
Dr. Joelle Getrajdman
Those problems – and the success Jacobi surgeons reported with ketamine pain control after thoracotomy – led the hospital to switch to a ketamine-based rib fracture protocol in 2007.
“As far as we know, we are the only people doing this routinely for multiple rib fractures,” Dr. Joelle Getrajdman, a second-year surgery resident at the medical center, said at the annual clinical congress of the American College of Surgeons.
Patients there with two or more rib fractures get a low-dose peripheral intravenous infusion of ketamine 0.05 mg/kg per hour while in the ICU and step-down unit, along with other pain medications as indicated. The hospital discontinues ketamine once patients leave the step-down unit to prevent diversion for illicit use.
To see how well the protocol has worked, the investigators reviewed all 128 adult trauma patients who received ketamine for multiple rib fractures from 2007 to 2014.
These patients were 60 years old on average, with a median of six rib fractures, many of them bilateral. Almost half had injury severity scores above 15, and most had chest Abbreviated Injury Scores of at least 3. Pneumo- and hemothoraces were common. Patients spent a mean of 6 days in the surgical ICU and 13 days in the hospital.
Along with ketamine, almost all had a morphine or hydromorphone (Dilaudid) patient-controlled analgesia (PCA) pumps, more than half received IV ketorolac (Toradol), and about 40% IV Tylenol. Only 14% had paravertebral or intercostal blocks.
Fourteen patients (10.9%) developed pneumonia, and four (3.1%) died, which compares favorably with outcomes in patients receiving epidurals. Historically, epidural analgesia for multiple traumatic rib fractures has been associated with about an 18% pneumonia rate, and about 9% mortality.
Ketamine side effects were minimal; none of the patients had hallucinations or tachycardia, and three (2.3%) were hypotensive on the drug.
Jacobi’s database did not record how many times patients used their PCA pumps, so the study did not have a direct measure of pain control. The investigators plan to look into this question prospectively.
Even so, when patients hurt from rib fractures, they breathe shallowly, which puts them at risk for pneumonia and death. “We have lower rates” of both than with epidurals, “so you could extrapolate that we must be controlling pain better,” Dr. Getrajdman said.
Ketamine at high doses is an anesthetic, but at lower doses it’s an antagonist of N-methyl-D-aspartate (NMDA), and a mild opioid receptor agonist, “so we can give patients the same amount of morphine but achieve a higher analgesic effect,” she said.
Ketamine had been the subject of intense interest in recent years for pain control in a wide variety of settings, as well as for psychiatric and other problems. Clinicaltrials.gov currently lists 138 open investigations of the drug.
Among them is a randomized trial from the Medical College of Wisconsin pitting ketamine against placebo for rib fracture pain following blunt trauma.
Dr. Getrajdman has no disclosures, and there was no outside funding for the work.