Background and Goal of Study:
In 2016 the World Health Organization strongly recommended intraoperative high inspired oxygen fraction (>80%) to reduce the incidence of surgical site infection (SSI).
However some authors warned about the potential increase of cardiovascular complications when applyingthis therapy.
The goal of the study was to audit if 80% FiO2 administered increased cardiovascular complications when compared to standard therapy (<50% FiO2).

Materials and Methods:
We reviewed the patients scheduled for elective oncologic colorectal surgery in 2015.
We divided them according to the intraoperative FiO2 received into two groups:
-HG: Hyperoxia Group(FiO2>80%)
-CG: Control Group(FiO2<50%)
We recorded demographic data (gender, age and ASA status and anaemia), previous cardiovascular disease (ischaemic heart disease, congestive heart failure and arrhythmia) and coronary risk factors
(hypertension, obesity, diabetes, dyslipidemia and smoking). We also recorded intraoperative data (type and duration of surgery).
We reviewed medical charts to determine the incidence of acute coronary syndrome (myocardial infarction or angina pectoris) and other cardiovascular complications (arrhythmia, congestive heart failure or stroke) in
the immediate postoperative period (up to 30 days) and in the delayed postoperative period (up to 2 years).
Statistical analysis: Fisher test to compare demographic data and also the incidence of the complications between the 2 groups. P value <0.05% was considered as significant.

Results and Discussion:
We included 100 patients divided between hyperoxia (n=53) and control group (n=47).
No differences were found between groups according to demographic or intraoperative data, preoperative cardiovascular disease or coronary risk factors.
In the 30-days postoperative period, the incidence of acute coronary syndrome was 0% in HG and 4.2% (n=2) in CG. Incidence of other cardiovascular complications was 2% in HG and 8.5% in CG. No significant differences were observed.
In the 2-year postoperative period, the incidence of acute coronary syndrome was 3.7% in HG and 2% in CG. The incidence of other cardiovascular complications was 17% vs 13% respectively. No significant differences were observed between two groups.

Conclusion:
Immediate or delayed cardiovascular complications doesn't seems to increase when applying hyperoxia to patients scheduled to elective colorectal surgery.

10 / DOES INTRAOPERATIVE HYPEROXIA INCREASE CARDIOVASCULAR COMPLICATIONS AFTER COLORECTAL SURGERY?