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Increased 30-day mortality seen with high admission lactate values after neck of femur fracture
There was a 24% mortality rate when patients were operated on with lactate levels that were a minimum of 3 mmol/L.
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In research that won the Arthritis Research UK best poster prize at the British Orthopaedic Association Congress, patients with serum venous lactate levels of 3 mmol/L or greater at admission after a hip fracture had an increased risk of death within 30 days compared to patients with levels at or less than 3 mmol/L at admission.
Investigators, who conducted the prospective study at Leicester Royal Infirmary, in Leicester, United Kingdom, enrolled 770 trauma patients in the study. The patients had a mean age of 80 years old and most had an isolated neck of femur fracture due to a fall.
The cohort did not include polytrauma patients or patients with subtrochanteric fractures, Rob Smith, BSc, MBChB, MRCS[Eng], told Orthopaedics Today Europe.
He said the venous serum lactate biomarker that he and his colleagues evaluated in this study is among those used to assess general and polytrauma patients.
Effect on frail patients
Image: Smith R
The investigators sought to determine whether having a venous serum lactate level of 3 mmol/L or greater — a cut-off previously identified in the literature — was related to increased morbidity in the elderly as is the case in the typically younger cohort of polytrauma patients.
According to Smith, the investigators also hoped to gain a better understanding of the impact on clinical outcomes due to the desire of some surgeons to take these patients to the operating theater after their lactate levels dropped. “In some polytrauma patients with a raised lactate there is a higher risk of mortality and morbidity while operating before that lactate starts to settle down,” he said.
The investigators made adjustments for age and gender “because both of those are known to be independent risk factors for mortality,” Smith said.
Differences in mortality seen
Based on the results for 30-day mortality, Smith and colleagues found 24% mortality in patients with lactate levels at or above 3 mmol/L. This was nearly four times greater than the mortality of 6.9% that they identified in patients with preoperative lactate below the cut-off point.
Smith said, “The mortality rate at 30 days for neck of femur fractures is anywhere from 8% to 10%, so it is certainly double the average.”
The severity of the difference between the mortality for the two groups was more surprising to Smith and his colleagues than the fact that a difference existed between the groups, since some of the researchers had done preliminary work in this area and understood many of the main issues in this patient population.
Fluid resuscitation, blood transfusion and oxygen therapy were some methods that Smith said could be used to lower the lactate values in at-risk patients so they can undergo surgery sooner. “In some people we are starting to monitor it closely,” Smith said. But, part of the conundrum in this scenario is the need to balance the possibility of an increased time to surgery and the discomfort patients have as they wait for their lactate levels to drop.
“Certainly, in our institution, this has been quite a new finding,” he said. “Clearly, what we do not know yet is if the lactate is reduced preoperatively, does that make a difference, and that is the next study.”
Despite adjustments in the study for American Society of Anesthesiology grade, which was done to account for other common comorbidities in this patient population, there remained an independent risk from the lactate that was elevated on admission, Smith said.
The study abstract suggested that venous lactate may be a useful tool to stratify patients with neck of femur fractures by risk of mortality. – by Susan M. Rapp
- Reference:
- Venketesan M. Paper #558. Presented at: British Orthopaedic Association Annual Congress; Oct. 1-4, 2013. Birmingham, England.
- For more information:
- Rob Smith, BSc, MBChB, MRCS[Eng], can be reached at Gwendolen Rd., Leicester LE5 4PW, United Kingdom; email: robert.p.smith@uhl-tr.nhs.uk.
Disclosure: Smith has no relevant financial disclosures.