Potential advantages of patient-ventilator synchrony

During conventional mechanical ventilation, fixed set pressure, flow, and tidal volume result in a mismatch between patient and ventilator inspiratory time and in a patient's inability to adapt to changing ventilatory demand. Synchrony between the patient and ventilator improves neuromuscular coupling and the ability to adapt to increased ventilatory demand or loading. The sensation of dyspnea prevents ineffective inspiratory efforts and attenuates periodic breathing during sleep.     

Interactive effects of corticosteroid and mechanical ventilation on diaphragm muscle function

Information on the interactive effects of methylprednisolone, controlled mechanical ventilation (CMV), and assisted mechanical ventilation (AMV) on diaphragm function is sparse. Sedated rabbits received 2 days of CMV, AMV, and spontaneous breathing (SB), with either methylprednisolone (MP; 60 mg/kg/day intravenously) or saline. There was also a control group. In vitro diaphragm force, myofibril ultrastructure, αII-spectrin proteins, insulin-like growth factor-1 (IGF-1), and muscle atrophy F-box (MAF-box) mRNA were measured. Maximal tetanic tension (P(o)) decreased significantly with CMV. Combined MP plus CMV did not decrease P(o) further. With AMV, P(o) was similar to SB and controls. Combined MP plus AMV or MP plus SB decreased P(o) substantially. Combined MP plus CMV, MP plus AMV, or MP plus SB induced myofibrillar disruption that correlated with the reduced P(o). αII-spectrin increased, IGF-1 decreased, and MAF-box mRNA increased in both the CMV group and MP plus CMV group. Short-term, high-dose MP had no additive effects on CMV-induced diaphragm dysfunction. Combined MP plus AMV impaired diaphragm function, but AMV alone did not. We found that acute, high-dose MP produces diaphragm dysfunction depending on the mode of mechanical ventilation.     

Salivary paracetamol elimination kinetics during the menstrual cycle.

Studies were done to examine the influence of the menstrual cycle on the elimination kinetics of paracetamol. Salivary concentrations of paracetamol were determined after oral administration of 1 g of paracetamol on day 3, 10, 14, 20 and 25 of the menstrual cycle in normal healthy women volunteers with regular menstrual cycles. There was no significant difference in elimination half-life (t 1/2) or metabolic clearance rate (CL) between the various days of the menstrual cycle. The result suggests that paracetamol kinetics are not altered by the hormonal changes occurring during the menstrual cycle.     

Differential outcomes from metabolic ratios in the identification of CYP2D6 phenotypes–focus on venlafaxine and O-desmethylvenlafaxine

Background  

Venlafaxine (VEN), a well accepted anti-depressant, is metabolized through the cytochrome P 450 (CYP) 2D6 isozyme to form O-desmethyvenlafaxine (ODV). Due to the involvement of CYP2D6, the formation of ODV is influenced by genetic polymorphism. We used standard tools of assessment to explore the phenotypic distribution in a retrospective manner using the pharmacokinetic (PK) data of VEN and ODV obtained from several bioavailability/bioequivalence (BA/BE) studies in healthy subjects using the reference formulation.