We describe a patient who presented on two occasions with severe hypobicarbonatemia and an associated high anion gap on enzymatic analysis. She also had profound hyperlipidemia. Her low bicarbonate was shown to be factitious by analysis of her blood using a direct ionselective electrode method. Reanalysis of blood samples after treatment with a lipid clearing agent resulted in marked improvement in the bicarbonate level. We suggest that the light scattering effect of the hyperlipidemia interfered with the photometric analysis causing this factitious phenomenon.

Minimally invasive spine surgery is increasingly used to treat various spinal pathologies with the goal of minimizing destruction of the surrounding tissues. Rhabdomyolysis (RM) is a rare but known complication of spine surgery, and acute renal failure (ARF) is in turn a potential complication of severe RM. The authors report the first known case series of RM and ARF following minimally invasive lateral spine surgery. The authors retrospectively reviewed data in all consecutive patients who underwent a minimally invasive lateral transpsoas approach for interbody fusion with the subsequent development of RM and ARF at 2 institutions between 2006 and 2009. Demographic variables, patient home medications, preoperative laboratory values, and anesthetic used during the procedure were reviewed. All patient data were recorded including the operative procedure, patient positioning, postoperative hospital course, operative time, blood loss, creatine phosphokinase (CPK), creatinine, duration of hospital stay, and complications. Five of 315 consecutive patients were identified with RM and ARF after undergoing minimally invasive lateral transpsoas spine surgery. There were 4 men and 1 woman with a mean age of 66 years (range 60–71 years). The mean body mass index was 31 kg/m2 and ranged from 25 to 40 kg/m2. Nineteen interbody levels had been fused, with a range of 3–6 levels per patient. The mean operative time was 420 minutes and ranged from 315 to 600 minutes. The CPK ranged from 5000 to 56,000 U/L, with a mean of 25,861 U/L. Two of the 5 patients required temporary hemodialysis, while 3 required only aggressive fluid resuscitation. The mean duration of the hospital stay was 12 days, with a range of 3–25 days Rhabdomyolysis is a rare but known potential complication of spine surgery. The authors describe the first case series associated with the minimally invasive lateral approach. Surgeons must be aware of the possibility of postoperative RM and ARF, particularly in morbidly obese patients and in procedures associated with prolonged operative times.

Lactic acidosis is a rare and often lethal complication of metformin therapy. We describe a patient who ingested at least 52 g, and possibly more, of metformin and presented with severe lactic acidosis and acute renal failure. He was treated with prolonged hemodialysis: a 3.5 h treatment that did not result in significant clinical improvement, followed by an additional 31 h treatment. With this treatment regimen, his lactate levels gradually decreased and his clinical status improved. A metformin level drawn approximately 25 h after the initiation of the second hemodialysis treatment was still elevated at about five times the upper therapeutic limit. It is suggested that prolonged dialysis is indicated in patients with severe metformin overdose, particularly those with renal failure. In patients whose cardiovascular status permits, prolonged hemodialysis should be strongly considered.

No abstract