Anesthetic considerations in mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes syndrome: a case series.

PURPOSE: Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes syndrome (MELAS) is a rare inherited mitochondrial disorder associated with severe multiorgan pathology and stress-induced episodes of metabolic decompensation and lactic acidosis. The purpose of this case series is to review the medical records of patients with MELAS who underwent anesthetic care at the Mayo Clinic to observe their perioperative responses to anesthesia and to assess outcomes. PRINCIPAL FINDINGS: From September 1997 to October 2010, nine patients with MELAS were identified who underwent 20 general anesthetics, 12 prior to MELAS diagnosis. Debilitating neurologic symptoms involved eight patients, and three patients had substantial cardiac comorbidities. The patients tolerated commonly used anesthetics and muscle relaxants, including succinylcholine. Lactated Ringer's solution was used frequently. One patient was noted to have elevated postoperative serum lactate, but his serum lactate was chronically elevated. Metabolic acidosis was not observed in any patient. Hyponatremia and hyperkalemia, sometimes profound, were observed in seven patients, but these abnormalities also occurred at times remote from surgery. Two patients developed renal dysfunction following cardiac surgery and abdominal surgery for severe sepsis. CONCLUSION: The MELAS patients developed episodes of hyponatremia and hyperkalemia of variable severity unrelated to the timing of surgery, suggesting these patients are prone to major electrolyte disturbances. Given the propensity to develop acid-base disturbances and lactacidemia, it is prudent to review and normalize electrolyte abnormalities and to adjust the anesthetic plan accordingly. Fortunately, the limited data suggest that patients with MELAS tolerate commonly used anesthetic drugs well.

Effects of propofol on intraoperative parathyroid hormone monitoring in patients with primary hyperparathyroidism undergoing parathyroidectomy: a randomized control trial.

PURPOSE: Serial measurements of parathyroid hormone (PTH) serum concentrations aid parathyroidectomy surgery. There are concerns that propofol may increase PTH concentrations and/or interfere with PTH assays. The primary purpose of this study is to determine the effects of propofol on PTH concentrations in patients with primary hyperparathyroidism and to determine its effect on PTH assays. METHODS: Thirty patients with primary hyperparathyroidism were assigned randomly to induction and maintenance with either propofol or sevoflurane. Blood samples for PTH assays were obtained pre-induction, immediately after induction, ten minutes after induction, and after excision of parathyroid adenoma. The primary endpoint was the PTH concentration at ten minutes after induction. This endpoint was compared between groups using analysis of covariance adjusting for pre-induction PTH. An in vitro study was performed with four different pools of PTH concentrations that were spiked with increasing concentrations of propofol. Serum PTH was measured in duplicate in each sample and analyzed using repeated measures analysis of variance. RESULTS: At ten minutes after induction, PTH concentrations did not differ significantly between groups (least square mean difference -7.0 pg·mL(-1); 95% confidence interval, -34.2 to +20.2). The PTH level in vitro did not change significantly with increasing propofol concentrations. DISCUSSION: Parathyroid hormone concentrations in patients with primary hyperparathyroidism were not affected by the type of anesthesia (propofol vs sevoflurane). Furthermore, propofol was found not to interfere with PTH assays at clinically relevant concentrations. There is no evidence to support the avoidance of a propofol anesthetic for parathyroid surgery.

Perioperative course and intraoperative temperatures in patients with osteogenesis imperfecta.

BACKGROUND AND OBJECTIVES: Concerns persist regarding the association of osteogenesis imperfecta with perioperative complications and intraoperative hyperpyrexia. The purpose of this study is to examine whether osteogenesis imperfecta patients develop intraoperative hyperthermia and to describe anaesthesia-related complications. METHODS: Medical records of 49 osteogenesis imperfecta patients undergoing 180 anaesthetics were reviewed for the presence of perioperative anaesthetic complications. In a subset of osteogenesis imperfecta non-cardiac surgical patients with available intraoperative temperatures (n = 31), a 2: 1-matched study design was utilised to examine intraoperative temperature and metabolic changes. Temperatures and end-tidal carbon dioxide measurements were analysed using a mixed linear model with temperature as the dependent variable with group (osteogenesis imperfecta vs. control) and time included as explanatory variables. RESULTS: In this cohort of 49 osteogenesis imperfecta patients, there were no perioperative complications associated with anaesthetic care. Intraoperative temperature during non-cardiac surgery was found to increase over time in both osteogenesis imperfecta and control patients (main effect of time, P < 0.001), but no overall difference was observed between the groups (main effect of group, P = 0.589). The changes in temperature did not differ between groups at any measured intervals (time-by-group interaction, P = 0.938). For end-tidal carbon dioxide, no significant differences were detected (main effect of time, P = 0.747; main effect of group, P = 0.545; and time-by-group interaction, P = 0.800). DISCUSSION: Osteogenesis imperfecta patients undergoing non-cardiac surgery experienced mild intraoperative hyperpyrexia which was not different from those without osteogenesis imperfecta.

Anesthetic management of patients with Huntington disease.

BACKGROUND: Huntington disease (HD) is a rare autosomal dominant disease with symptoms of chorea, dystonia, incoordination, cognitive decline, and behavioral difficulties. Abnormal responses to anesthesia have been reported in case reports and raised concerns regarding the safety of anesthesia in this patient population. METHODS: We performed a computerized search of the Mayo Clinic medical records database searching for patients with HD who underwent general anesthesia. Medical records were reviewed for anesthetic technique, medications used, and postoperative complications. RESULTS: We identified 11 patients with genetically confirmed HD who underwent 17 general anesthetics. Psychiatric medication use was common, with 6 patients using antipsychotics, 7 patients using antidepressants, and 3 patients using benzodiazepines. Succinylcholine was used in 7 anesthetics, and nondepolarizing neuromuscular blocking drugs in 11 anesthetics, all without adverse effects. Patients had normal responses to induction and maintenance of anesthesia without adverse effects. Serious postoperative complications did not occur. CONCLUSION: Contrary to previous case reports, we found that patients with HD have normal responses to general anesthesia. However, the anesthesiologist should be aware of interactions between anesthetics and psychiatric medications frequently used by these patients. Measures should also be taken to minimize the risk of pulmonary aspiration because bulbar dysfunction may be a manifestation of this disease.

Two generalizable routes to terminal carbido complexes.

Desulfurization of the thiocarbonyl ligand in square pyramidal [Ru(CS)Cl2(PCy3)2] (1-S) via sulfur atom abstraction using [Mo(H)(eta2-Me2CNAr)(N[i-Pr]Ar)2] forms [Ru(C)Cl2(PCy3)2] (1) cleanly over several hours in benzene; isolated yield is 55%. Complex 1 is also formed in 87% isolated yield upon reaction of [Ru(CHR)(PCy3)2Cl2] (R = p-C6H4Me, 2; Ph, 3) with vinyl acetate in dichloromethane. Complex 1-S is re-formed quantitatively from 1 upon treatment with elemental sulfur in CH2Cl2, but is prepared most conveniently by treatment of crude [Ru(CS)Cl2(PPh3)2(OH2)] with excess PCy3 in toluene. Nearly quantitative conversion of 1 to [Ru(CO)Cl2(PCy3)2] (1-O) occurs upon addition of dimethyldioxirane solution in acetone to 1 dissolved in CH2Cl2 at ca. -90 degrees C.