Effect of maternal oxygen supplementation for parturient undergoing elective cesarean section by high-flow nasal oxygen compared with room air on fetal acidemia: study protocol for a randomized controlled trial.

BACKGROUND: Maternal oxygen supplementation is usually used as an intrauterine resuscitation technique to prevent fetal hypoxia and acidemia during delivery. However, there has been a great deal of controversy regarding the effects of prophylactic maternal oxygen during cesarean section, during which the incidence of fetal acidemia seems to be higher compared with that during labor. High-flow nasal oxygen (HFNO) can improve oxygenation better in patients with high-flow oxygen airflow. The purpose of this study is to determine whether maternal oxygen supplementation with HFNO has a positive effect on fetal acidemia during cesarean section through umbilical arterial blood gas analysis. METHOD: This prospective, single-center, randomized, double-blinded trial will enroll 120 patients undergoing cesarean section. Participants will be randomly assigned to the HFNO group or air group at a 1:1 ratio. For parturients in the HFNO group, the flow rate is 40L/min, and the oxygen is heated to 37℃ with humidity 100% oxygen concentration through the Optiflow high-flow nasal oxygen system. And for the air group, the flow rate is 2 L/min with an air pattern through the same device. The primary outcome was umbilical artery (UA) lactate. Secondary outcomes include UA pH, PO2, PCO2, BE, the incidence of pH < 7.20 and pH < 7.10, Apgar scores at 1 and 5 min, and neonatal adverse outcomes. DISCUSSION: Our study is the first trial investigating whether maternal oxygen supplementation with HFNO can reduce the umbilical artery lactate levels and the incidence of fetal acidemia in cesarean section under combined spinal-epidural anesthesia. TRIAL REGISTRATION: ClinicalTrials.gov NCT05921955. Registered on 27 June 2023.

Morphine pretreatment protects against cerebral ischemic injury via a cPKCγ-mediated anti-apoptosis pathway.

It has been reported that morphine pretreatment (MP) can exert neuroprotective effects, and that protein kinase C (PKC) participates in the initiation and development of ischemic/hypoxic preconditioning in the brain. However, it remains unknown whether PKC is involved in MP-induced neuroprotection. The aim of the present study, which included in vivo and in vitro experiments, was to determine whether the conventional γ isoform of PKC (cPKCγ) was involved in the protective effects of MP against cerebral ischemic injury. The present study included an in vivo experiment using a mouse model of middle cerebral artery occlusion and an in vitro experiment using neuroblastoma N2a cells with oxygen-glucose deprivation (OGD). Furthermore, a cPKCγ antagonist, Go6983, was used to determine the involvement of cPKCγ in the protective effects of MP against cerebral ischemic injury. In the in vivo experiment, neurological deficits, ischemic infarct volume, neural cell damage, apoptosis and caspase-3 activation were evaluated. In the in vitro experiment, flow cytometry was used to determine the activation of caspase-3 in N2a cells with OGD. It was found that MP protected against cerebral ischemic injury. However, intracerebroventricular injection of the cPKCγ antagonist before MP attenuated the neuroprotective effect of MP and increased the activation of cleaved caspase-3. These findings suggested that MP may provide protection against cerebral ischemic injury via a cPKCγ-mediated anti-apoptosis pathway.

[Evidence of waveform information in arterial blood gas by beat-by-beat sampling method in patients with normal heart function].

OBJECTIVE: Since 2011 EB-APS conference, we hypotheses that phase switching of inspiration-expiration is dominantly initiated by oscillatory information PaO2, PaCO2 and [H+] via fast peripheral chemical receptors. However, the evidence of the waveform of ABG is lack. METHODS: Six surgery patients with normal heart function and negative Allen test, had been placed the arterial catheterization directly connected to 3 x 1 000 mm pre-heparin plastic pipe for continuous collecting arterial blood. We counted the number of heart beat for the blood collecting time, and separated the blood pipe into the heart beat numbers' short pieces using haemostatic forceps, then put pipe into iced water at once fir analyzing PaO2, PaCO2, pH and SaO2 as soon as possible. We selected two breaths cycles of waveform from each patient for data calculations of magnitudes and time interval. RESULTS: The heart beat numbers for filling blood into pipe were 16 ± 2, and all covered more than 2 breathing cycles. Each breathing cycle is cover 5 ± 0.6 heart beat. There were significant changes of PaO2, PaCO2, [H+] a and SaO2 (i.e. the highest high values compare to the next lowest values, P < 0.05). The time interval of changing PaO2, PaCO2, [H+]a and SaO2 magnitudes were 11.28 ± 1.13 mmHg, 1.77 ± 0.89 mmHg, 1.14 ± 0.35 nmol/L and 0.52% ± 0.44% respectively. CONCLUSION: This simple continuous beat-by-beat arterial blood sampling and ABG analyzing method is new and practicable. We obtain a clear evidence of periodic parameters ABG waveform, which following breathing cycle.

[Evidence of waveform information in arterial blood gas by beat-by-beat sampling method in patients with heart failure].

OBJECTIVE: We investigate the magnitudes of waveform changes of arterial blood gas (ABG) in patients with heart failure. METHODS: Five patients with heart failure were selected, continuous collecting radial artery blood and measured PaO2, PaCO2, pHa and Sao2. We selected two typical breaths cycles of waveform changes of ABG from each patient for data analysis. Comparison of the adjacent highest and lowest values to verify the presence of a periodic waveform changes of ABG, and in addition, we used t test to analysis the range of waveform changes of ABG in patients with heart failure and patients with normal cardiac function and compared whether the difference between them. RESULTS: The 5 patients (2 surgical and 3 ICU) with heart failure, were 4 male and 1 female, (69 ± 7)year, (169 ± 10) cm, (75 ± 19)kg, LVEF = (38 ± 3)%. The heart beat numbers for full blood into the blood sampling pipe were 17 ± 2, and all covered more than 2 breath cycles. There were significant changes of PaO2, PaCO2, [H+]a and SaO2 (P < 0.05). The magnitudes of changing PaO2, PaCO2, [H+]a and Sao2 were (7.94 ± 2.02)mmHg, (1.18 ± 0.56)mmHg, (0.54 ± 0.17)nmol/L and (0.21 ± 0.07)%, and they were (6.1 ± 1.5)%, (3.2 ± 1.5)%, (1.5 ± 0.5)% and (0.2 ± 0.1)% from their mean respectively. Even these magnitudes fo all ABG parameters were trendily lower than those of patients with normal cardiac function, but only PaO2 and [H+]a were significant (P < 0.05). CONCLUSION: Using this simple continuous beat-by-beat arterial blood sampling method, we obtained a clear evidence of periodic waveform of ABG parameters following by breath cycle in patients with heart failure, but the magnitude trendily be decreased.

[Effectiveness and safety of tranexamic acid in patients receiving on-pump coronary artery bypass grafting without clopidogrel and aspirin cessation].

OBJECTIVE: To evaluate the effectiveness and safty of tranexamic acid in patients receiving on-pump coronary artery bypass grafting (CABG) without clopidogrel and aspirin cessation. METHODS: The current study is a prospective, randomized and placebo-control trial. A total of 116 patients receiving selective on-pump CABG with their last ingestion of clopidogrle and aspirin within 7 days preoperatively were recruited. Despite 6 patients withdrawal their consent, the rest 110 were randomized to receive tranexamic acid or placebo. The tranexamic acid regimen was a bolus of 10 mg/kg followed by a maintenance of 10 mg·kg(-1)·h(-1) throughout the surgery. The primary outcome was the volume of allogeneic erythrocyte transfused perioperatively. RESULTS: Baseline characteristics were comparable between the groups. In patients receiving tranexamic acid and placebo respectively, the volume of allogeneic erythrocyte transfused was 4.0 (7.5) units and 6.0(6.0) units (W = 1021, P < 0.01). In these 2 groups respectively, blood loss was 930 (750) ml and 1210 (910) ml (W = 1042, P < 0.01), the incidence of major bleeding was 50.9% and 76.4% (χ(2) = 7.70, P < 0.01), the incidence of reoperation was 0 and 9.1% (χ(2) = 5.24, P = 0.02); the volume of plasma transfused was 400 (600) ml and 600 (650) ml (W = 1072, P = 0.01), the exposure of plasma was 60.0% and 85.5% (χ(2) = 8.98, P < 0.01) and the exposure to any allogeneic blood products was 85.5% and 98.2% (χ(2) = 5.93, P = 0.01). Perioperative mortality, morbidity and the incidence of adverse events were balanced between the groups without statistical significance. CONCLUSION: Tranexamic acid reduced significantly postoperative bleeding and transfusion in patients receiving on-pump CABG without clopidogrel and aspirin cessation.

[Protection of ulinastatin against myocardial injury induced by off-pump coronary artery bypass graft surgery: report of 24 cases].

OBJECTIVE: To investigate the protective effect of ulinastatin against myocardial injury induced by off-pump coronary artery bypass graft surgery (OPCAB). METHODS: Twenty-four patients undergoing OPCAB were randomly divided into 2 equal groups: ulinastatin group in which ulinastatin was infused intravenously, firstly at the concentration of 6000 U/kg dissolved in 50 ml normal saline for 30 min and then at the speed of 1000 U.kg(-1).h(-1) up to the end of operation, and control group that underwent infusion of normal saline of the same volume. Blood samples were collected before skin incision, 0.5 h after the completion of vascular anastomosis, and 2, 6, and 18 h after the operation to detect the plasma level of cardiac troponin 1 (cTn1). RESULTS: The cTn1 levels 2, 6, and 18 h after the operation of both groups were all significantly higher than those before skin incision (all P < 0.01). The cTn1 levels 0.5 h after the completion of vascular anastomosis, and 2, 6, and 18 h after the operation of the ulinastatin group were all significantly lower than those of the control group (all P < 0.01). CONCLUSION: Ulinastatin decreases the cTn1 level that increases peri-operatively, thus reducing the risk of myocardial injury in patients undergoing OPCAB.

Passive graft perfusion in off-pump coronary artery bypass grafting.

BACKGROUND: Myocardial protection during off-pump coronary artery bypass grafting (OPCABG) is a multifactorial problem in which maintaining stable systemic hemodynamics is very important. In this study passive graft perfusion (PGP) was applied to investigate the effect during and after OPCABG as evaluated by cardiac troponin I (CTnI) and hemodynamic indexes. METHODS: Thirty first-time patients underwent OPCABG under one surgeon. They were randomly divided into two groups: The passive graft perfusion group (PGP, n = 15) received distal coronary perfusion during the anastomosis and immediate graft perfusion after the distal anastomosis. The control group, no graft perfusion group, (NGP, n = 15) received no graft perfusion after the distal anastomosis. The results of the two protocols were evaluated by concentration of CTnI and hemodynamic indexes before induction and after operation. RESULTS: There were no statistically significant differences between these two groups in their perioperation parameters. The level of CTnI increased postoperatively, reached its peak at 6 hours (P < 0.05) and recovered by the 6 days postoperative. Compared with the control group the concentration of CTnI in the PGP group was significantly lower at 6 and 24 hours (P < 0.01). Compared with the NGP group, cardiac index (CI) in the PGP group was higher at 12 and 24 hours after operation (P < 0.05). The period of mechanical ventilation was significantly shorter in the PGP group than in the NGP group (P < 0.05). CONCLUSION: PGP can increase the flow to the myocardium and shorten the heart ischemia time, thus maintain stable systemic hemodynamics, supply a satisfactory CI after surgery and improve surgery outcome.

[Total arch replacement combined with stented elephant trunk implantation for Stanford type A aortic dissection].

OBJECTIVE: To improve the long term outcomes of the surgery for Stanford type A aortic dissection, we performed ascending aorta and total aortic arch replacement combined with transaortic stented graft implantation into the descending aorta for acute and chronic type A aortic dissection. METHODS: From April 2003 to March 2004, 40 consecutive patients with acute or chronic Stanford type A aortic dissection underwent this procedure. Right axillary artery cannulation was routinely used for cardiopulmonary bypass and selected cerebral perfusion. The stented elephant trunk was implanted through the aortic arch under hypothermic circulatory arrest. The stented elephant trunk was a 10 cm long self expandable graft. Enhanced electric beam computed tomography (EBCT) was performed in each patient before discharge, three month after surgery, and once each year after discharge to evaluate the postoperative time course of the residual false lumen. RESULTS: Cardiopulmonary bypass time was (166 +/- 38) min, average cross clamp time was (107 +/- 28) min, and average selective cerebral perfusion and lower body arrest time was (30 +/- 15) min. The in-hospital mortality was 5% (2/40). One patient died of multi-organ failure postoperatively and another died of cerebral infarction 2 month after surgery. One suffered from spinal cord injury perioperatively. There was no late death during follow up. CONCLUSION: Ascending aorta and total aortic arch replacement combined with transaortic stented graft implantation into the descending aorta is an effective way in closing the residual false lumen of the descending aorta and might contribute to the better long term outcomes of type A aortic dissection. Our half mortality of 2 patients suffering acute renal failure suggests that this group may be candidates for medical or delayed surgical intervention. Conversely, our 5% mortality rate for those renal intact patients warrant aggressive and expeditious surgical treatment.