Extended-time of noninvasive positive pressure ventilation improves tissue perfusion after coronary artery bypass surgery: a randomized clinical trial

Abstract Objective: To compare the effects of extended- versus short-time noninvasive positive pressure ventilation on pulmonary function, tissue perfusion, and clinical outcomes in the early postoperative period following coronary artery bypass surgery in patients with preserved left ventricular function. Methods: Patients were randomized into two groups according to noninvasive positive pressure ventilation intensity: short-time noninvasive positive pressure ventilation n=20 (S-NPPV) and extended-time noninvasive positive pressure ventilation n=21 (E-NPPV). S-NPPV was applied for 60 minutes during immediate postoperative period and 10 minutes, twice daily, from postoperative days 1-5. E-NPPV was performed for at least six hours during immediate postoperative period and 60 minutes, twice daily, from postoperative days 1-5. As a primary outcome, tissue perfusion was determined by central venous oxygen saturation and blood lactate level measured after anesthetic induction, immediately after extubation and following noninvasive positive pressure ventilation protocols. As a secondary outcome, pulmonary function tests were performed preoperatively and in the postoperative days 1, 3, and 5; clinical outcomes were recorded. Results: Significant drop in blood lactate levels and an improvement in central venous oxygen saturation values in the E-NPPV group were observed when compared with S-NPPV group after study protocol (P<0.01). The E-NPPV group presented higher preservation of postoperative pulmonary function as well as lower incidence of respiratory events and shorter postoperative hospital stay (P<0.05). Conclusion: Prophylactic E-NPPV administered in the early postoperative period of coronary artery bypass surgery resulted in greater improvements in tissue perfusion, pulmonary function and clinical outcomes than S-NPPV, in patients with preserved left ventricular function. Trial Registration: Brazilian Registry of Clinical trial - RBR7sqj78 - http://www.ensaiosclinicos.gov.br

The levels of serum lactate, lactate clearance rate and transaminase in septic rats and their relationship with liver damage / 中国医师杂志

Objective To explore the serum lactic acid,transaminase and their relationship with liver pathological damage in sepsis rats,whether a correlation exists between serum lactate clearance rate and transaminase in sepsis rats,and whether they can be used as indicators for the prediction and evaluation of septic rats liver injury.Methods A total of 150 clean Sprague-Dawley (SD) rats was divided into normal group (n =50),sham operated group (n =50),and the cecal ligation and puncture (CLP) (n =50).Ten rats were killed after successful surgery at the 6th,12th,24th,48th,and 72nd hour in CLP group,respectively.At each time point,10 normal rats and 10 sham-operated rats were taken as a control in the corresponding time point.The liver tissue was obtained for pathological analysis.The levels of lactate and liver transaminase were detected and the lactate clearance rate was calculated.The levels of lactate and transaminase at each time point were statistically compared.The correlation analysis was performed among serum lactate,transaminase,and liver damage pathological changes.Results The rat hepatocytes in CLP group begin to appear at the 6th hour,and the damage was gradually enhanced at the 12th,24th,and 48th,and up to the worst damage at the 48th time point.The levels of lactate and alanine aminotransferase (ALT)in CLP group at the 12th and 24th hour were significantly elevated compared with the normal and sham operation groups (P ＜0.05); The level of aspartate aminotransferase (AST) in CLP group at the 6th,12th,24th,48th,and 72nd hour was significantly elevated compared with the normal and sham operation groups (P ＜ 0.05).A positive correlation was found between the levels of ALT and lactate (r =0.766,P ＜0.05),and a negative correlation was found between lactate clearance rate and ALT (r =-0.712,P ＜0.05).Conclusions In septic rats,both lactate and lactate clearance rate were correlated with ALT,and they were correlated with liver pathological damage.The level of lactate,lactate clearance rate,and ALT could be used as the key indicators to predict liver damage in septic rats.

Effects of hyperoxic-hyperosmotic sodium chloride solution on blood lactate and arterial blood gas in rabbits with hemorrhagic shock / 中国普通外科杂志

Objective To investigate the effects of hyperoxic-hyperosmotic sodium chloride solution(HHSCS) on arterial blood gas and blood lactate in rabbits with hemorrhagic shock, and evaluate the HHSCS effects on hemorrhagic shock resuscitation.Methods Hemorrhagic shock models were induced in 30 male rabbits.The median arterial pressure(MAP) was declined to 40mmHg within 10 minutes,then maintained for 60(minutes).The animals were then randomly divided into 3 groups:normal saline hyperoxic solution(NSO)group,hyperosmotic sodium chloride solution(HS)group and HHSCS group.Sixty minutes later,NSO,HS or HHSCS 6ml/kg was infused intravenously in 5 minutes.Heart rate(HR) 、respiratory rate(RR)、 MAP and urine drops(UD) before shock and after fluid infusion were recorded;blood lactate(BL) and blood gas were measured before shock,60min after shock,and 30min,60min,120min postinfusion.Finally,the(rabbits) were killed by bleeding,the lungs were observed in autopsy,and the lung coefficient was measured.Results HS and HHSCS more effectively raised MAP,enhanced heart function,and increased UD than NSO.HHSCS group significantly reduced BL.At 60,120min after infusion,SaO_2 in HHSCS group was(significantly) higher than that in HS group and NSO group(P