Perioperative supplemental oxygen and oxidative stress in patients undergoing moderate- to high-risk major abdominal surgery - A subanalysis of randomized clinical trial.

STUDY OBJECTIVE: Oxidative stress plays a pivotal role in the development and aggravation of cardiovascular diseases. The influence of intraoperative inspired oxygen concentrations on oxidative stress is still not entirely known. Therefore, we evaluated in this sub-study if supplemental oxygen affects the oxidation-reduction potential in patients at-risk for cardiovascular complications undergoing moderate- to high-risk major abdominal surgery. DESIGN: Sub-study of a prospective parallel-arm double-blinded single-center superiority randomized trial. SETTING: Operating room and postoperative recovery area. INTERVENTION: Administration of 0.8 FiO2 versus 0.3 FiO2 throughout surgery and for the first two postoperative hours. MEASUREMENTS: The primary outcome was the static oxidation-reduction potential (sORP) and the oxidation-reduction potential capacity (cORP) between both groups. The secondary outcome was the trend of sORP and cORP in the overall study population. We assessed sORP and cORP before induction of anesthesia, 2 h after induction of anesthesia, within 2 h after surgery and on the first and third postoperative day. MAIN RESULTS: 258 patients were analyzed. 128 patients were randomly assigned to the 80% oxygen group and 130 patients were randomly assigned to the 30% oxygen group. Postoperative sORP values did not differ significantly between the 80% and 30% oxygen group (effect estimate: -1.162 mV,95% CI: -2.584 to 0.260; p = 0.109). On average, we observed a change in sORP of 5.288 mV (95% CI:4.633 to 5.913, p < 0.001) per day. cORP values did not differ significantly between the 80% and 30% oxygen group (effect estimate: -0.015µC, (95%CI: -0.062 to 0.032; p = 0.524). On average, we observed a change in cORP values of -0.170µC (95%CI: -0.194 to -0.147, p < 0.001) per day. CONCLUSION: In contrast to previous reports, we could not find any evidence of an association between intraoperative supplemental oxygen and perioperative oxidative stress assessed by sORP and cORP. TRIAL REGISTRATION: clinicaltrials.gov: NCT03366857https://clinicaltrials.gov/ct2/show/NCT03366857?term=vienna&cond=oxygen&draw=2&rank=1.

Providing the best chest compression quality: Standard CPR versus chest compressions only in a bystander resuscitation model.

AIM OF THE STUDY: Bystander-initiated basic life support (BLS) for the treatment of prehospital cardiac arrest increases survival but is frequently not performed due to fear and a lack of knowledge. A simple flowchart can improve motivation and the quality of performance. Furthermore, guidelines do recommend a chest compression (CC)-only algorithm for dispatcher-assisted bystander resuscitation, which may lead to increased fatigue and a loss of compression depth. Consequently, we wanted to test the hypothesis that CCs are more correctly delivered in a flowchart-assisted standard resuscitation algorithm than in a CC-only algorithm. METHODS: With the use of a manikin model, 84 laypersons were randomized to perform either flowchart-assisted standard resuscitation or CC-only resuscitation for 5min. The primary outcome was the total number of CCs. RESULTS: The total number of correct CCs did not significantly differ between the CC-only group and the standard group (63 [±81] vs. 79 [±86]; p = 0.394; 95% CI of difference: 21-53). The total hand-off time was significantly lower in the CC-only group than in the standard BLS group. The relative number of correct CCs (the fraction of the total number of CCs achieving 5-6cm) and the level of exhaustion after BLS did not significantly differ between the groups. CONCLUSION: Standard BLS did not lead to an increase in correctly delivered CCs compared to CC-only resuscitation and exhibited significantly more hand-off time. The low rate of CCs in both groups indicates the need for an increased focus on performance during BLS training.