Surgery alters parameters of vitamin D status and other laboratory results

Fracture liaison services often perform laboratory testing, but these results may be altered by surgery. In 40 hip arthroplasty patients, many laboratory parameters of bone health relevance were reduced by 8-22% on the first post-operative day. Laboratory results obtained in the immediate post-surgery interval do not reliably ascertain baseline status.

INTRODUCTION

As secondary causes of osteoporosis are common, fracture liaison services often perform laboratory testing in the immediate post-fracture interval. We hypothesized that laboratory results obtained shortly after surgery may not accurately ascertain baseline status. If true, such alterations might confound subsequent fracture prevention efforts.

METHODS

Patients undergoing elective total hip arthroplasty were studied as a surrogate for hip fracture patients. Blood and urine were obtained 2 weeks before surgery, before anesthetic induction, on post-operative day one, and 6 weeks after surgery. Serum total and free 25-hydroxyvitamin D (25(OH)D), vitamin D-binding protein (DBP), calcium, creatinine, albumin (Alb), alkaline phosphatase (ALP), plasma hemoglobin (Hgb) and urinary DBP/creatinine ratio (UDBP/Cr) were measured.

RESULTS

Forty volunteers (28 women; 12 men) with mean age of 65.7 [8.7] years were studied. Laboratory results were stable from 2 weeks before to the day of surgery. On the first day after surgery, total 25(OH)D, DBP, calcium, creatinine, ALP, and Alb declined 8-22% (p < 0.0001); free 25(OH)D and Hgb declined by 8 and 15% (p < 0.01), respectively; and UDBP/Cr increased 32% (p < 0.01). Using a 25(OH)D <30 ng/mL threshold, vitamin D inadequacy prevalence increased from 38% before surgery to 68% the day after (p < 0.001). All laboratory values returned to baseline at 6 weeks after surgery.

CONCLUSIONS

Laboratory values are reduced immediately following elective total hip arthroplasty. Testing at that time does not accurately ascertain baseline status and may lead to elevated estimates of vitamin D inadequacy, incorrect interventions, and misallocation of healthcare resources.

Commentary. Balancing sedation and analgesia in the critically ill

The authors have presented a template for a systematic approach to comforting critically ill patients that can be modified to suit institutional preferences. In this algorithm, the cause of patient discomfort is sought with the priority given to pain and then to anxiety. Special attention is directed to the identification of correctable causes of pain and anxiety with application of nonpharmacologic techniques or medications to control patient discomfort. This step is followed by subsequent reassessment of the need for sedation or anxiolysis and titration or discontinuation of therapy as able. The benefits of protocol-driven care are becoming increasingly evident, and the authors believe the algorithm outlined here provides a rational and practical approach to patient management. It also prompts the caregiver to reevaluate patients' needs and to keep to patients at target sedation levels. Doing so can promote cost effectiveness, reduce side effects caused by drugs, and decrease morbidity and ICU stay. Any treatment protocol or algorithm is simply a guide to therapy and cannot address every clinical situation. The importance of individualized care and physician or care team judgment must be emphasized.

Acute myopathy during treatment of status asthmaticus with corticosteroids and steroidal muscle relaxants

Acute myopathy in patients being treated for severe asthma has been recognized with increasing frequency since first being described in 1977. We report three patients treated for status asthmaticus who developed severe generalized weakness. Electrophysiologic studies and muscle biopsy revealed evidence of muscle destruction. Each of these patients was treated with high-dose corticosteroids and underwent prolonged neuromuscular blockade with a steroidal muscle relaxant. A review of the literature revealed 15 similar cases. We postulate that the combined effects of corticosteroids and muscle relaxants on the muscle cell may be responsible for this myopathy. Patients treated with corticosteroids and NMBs should be carefully monitored for the development of myopathy.