Hemodynamic effects of lidocaine in the thoracic paravertebral space during one-lung ventilation for thoracic surgery.

OBJECTIVE: There is increasing interest in the use of the thoracic paravertebral block (TPVB) in association with general anesthesia for lung-resection surgery. The aim of the study was to evaluate the hemodynamic effects of a 5-mg/kg lidocaine bolus injected in the thoracic paravertebral space during one-lung ventilation (OLV) in noncardiac patients undergoing thoracic surgery. DESIGN: Prospective, observational study. SETTING: Tertiary care university hospital. PARTICIPANT: Twenty patients undergoing thoracotomy for lung resection. INTERVENTIONS: In addition to standard monitoring, cardiac output, preload parameters (global diastolic volume, total intrathoracic blood volume, and systolic volume variation), and myocardial contractility (dP(max) and cardiac function index) were measured with an aortic transpulmonary thermodilution technique. MEASUREMENTS AND MAIN RESULTS: After OLV initiation, a paravertebral lidocaine bolus of 5 mg/kg (2%) caused decreases in the dP(max) and cardiac function index that lasted up to 30 minutes. Accompanying minor reductions in heart rate and systolic blood pressure required no vasoactive drugs and were self-limiting. None of the other hemodynamic parameters studied was significantly altered. CONCLUSIONS: In noncardiac patients, TPVB is associated with good hemodynamic stability, despite a small and transient decrease in myocardial contractility that could be related to the drug's systemic effects after its absorption.

Presence of methylated arginine derivatives in orthotopic human liver transplantation: relevance for liver function.

Orthotopic liver transplantation (OLT) is a frequent option in the treatment of liver diseases. During the cold ischemia period of the donor liver, there is an accumulation of metabolites that are potent inhibitors of the cytokine-inducible and endothelial nitric oxide synthase isoenzymes. We identified the presence of L-N-monomethylarginine and asymmetric dimethylarginine (ADMA) as the main inhibitors by means of analytic high-pressure liquid chromatography and mass spectrometry techniques. An average ADMA concentration of 450 micromol/L was measured in the preservation medium of donor livers with poor outcomes after OLT. A statistically significant relationship was observed between the concentration of methylated arginine derivatives in the graft and liver function after OLT. These data suggest that measurement of methylated arginine, released after liver protein catabolism, might provide an indication of functional status of the liver that can help the development of strategies intended to improve graft viability.

Importance of creatine kinase activity for functional recovery of myocardium after ischemia-reperfusion challenge.

To define the relation between the phosphoryl transfer via creatine kinase and the ability to recover from an ischemia-reperfusion challenge, the authors chemically inhibited creatine kinase activity with iodoacetamide (IAm) and then measured myocardial recovery after 2, 10, or 30 min of global ischemia followed by 30 min of reperfusion in the isolated, arterially perfused interventricular septa of the rabbit heart. During normoxia, IAm (0.5 M perfused for 15 min) did not by itself modify developed tension, maximal rate of tension development, or resting tension. In ischemia, IAm pretreatment increased the rate of developed tension loss and highly diminished developed tension recovery after reperfusion for all the ischemia periods tested. Moreover, IAm significantly enhanced the maximal increase in the resting tension induced by 10 or 30 min of ischemia plus reperfusion. Lactate dehydrogenase activity in reperfusion was also significantly increased over untreated septa. On the basis of the present results, the authors suggest that the aggravating effects exhibited by IAm on the ischemic myocardium are compatible with its creatine kinase inhibition properties and that creatine kinase activity is essential for full recovery from an ischemia-reperfusion challenge.