R Greif et al The just discovered E...

R Greif et al The just discovered England Journal of Medicine Vol 342 (Jan 20 2000) 161-167

Surgical injurys are the second most commonly reported site of nosocomial infections. Approximately 500000 surgical anguish infections, now more commonly referr to as surgical site infections (SSIs), meet the eye annually, accounting for 3.7 million additional hospital days for patients and more than $16 billion in additional hospital expenses Consequently, as SSIs continue to be an important cause of morbidity and mortality worldwide, prevention continues to demand the attention of international, national, and local health care authorities, hospital administrators, and personnel at all plains of the perioperative milieu.

We have extended known that oxidative killing (ie, destruction according to oxidation) is an important defense against bacteria that cause SSIs. It also is known that oxidative killing be pendents on the partial pressure of oxygen (ie, oxygen tension) in contaminated tissue and that an effective mode of increasing oxygen tension in inadequately perfused tissue is to increase the concentration of inspired oxygen These researchers, therefore, experimented the hypothesis that supplemental oxygen administered during the perioperative period will decrease the incidence of SSIs.

Methodology. A multicenter inquiry was conducted in three European countries. Five hundr patients between 18 and 80 years of age undergoing elective major colorectal surgical deeds were assigned randomly to receive 30% or 80% inspired oxygen during their performance and for two hours after surgery Patients with a new history of fever, infection, serious malnutrition, or bowel obstruction and those undergoing no other than a minor colorectal procedure (eg polypectomy, isolated colostomy) were exclud from the contemplation All patients underwent standard bowel preparation with an electrolyte solution protocol the night before surgery and received antibiotic prophylaxis and standardized anesthesia induction protocol. After induction and placement of the endotracheal tube, each patient was assigned to single in kind of two groups through the use of a plant of computer-generated random numbers.

Patients in common group received 30% oxygen and 70% nitrogen, and patients in the other cluster received 80% oxygen and 20% nitrogen until immediately before extubation. Oxygen then was increased to 100% Oxygen concentrations were answered to assigned levels as betimes as deemed safe by the anesthesia care provider and continued for sum of two units hours postoperatively using a non-rebreathing mask. Anesthesia care providers were aware of the treatment assign places to assignments.

Cardboard shields were placed through flow meters and relevant monitors to hinder surgical staff members from determining the fraction of inspired oxygen

follows Chi-square tests were used to compare the number of SSIs in each arrange and multiple logistic regression analysis was used to determine predictive risk factors. Arterial oxygen saturation, partial urgency of arterial oxygen, subcutaneous oxygen tension, and muscle oxygen tension were significantly higher in patients in the form into groups that received 80% oxygen (P = 001) The incidence of SSIs was halved for patients in this dispose In the 80% oxygen clump 13 out of 250 patients expanded SSIs (rate 5.2, 95% confidence interval, 24% to 80%) compared with 28 disclosed of 250 patients in the 30% oxygen dispose (rate 11.2, 95% confidence interval, 73% to 151%) Multiple logistic regression analysis revealed that merely the use of 30% oxygen correlated significantly with the risk of infection (odd ratio 23 95% confidence interval, 12% to 46%)

Discussion. This contemplation demonstrates that supplemental oxygen administered during surgery and for single in kind to two hours postoperatively using a nonrebreathing mask effectively reduc the risk of SSIs by way of more than 50%. Previous studies demonstrate that for a patient with normal peripheral perfusion, the subcutaneous oxygen tension is related linearly to the arterial oxygen tension and that there is an inverse correlation between subcutaneous tissue oxygen tension and the incidence of SSI. These studies hint that supplemental oxygen should be given for single in kind to two days after surgical proceedings Other studies reveal that supplemental oxygen administered between the walls of nasal prongs had no validity on SSIs; however, these researchers indicate that using a nonrebreathing mask for couple hours after surgery was effective in reducing the rate of SSIs. Consequently the use of a nonrebreathing mask is essential and as small in number as two hours during the postoperative period is required; however, additional studies are penuryed to determine the optimum detail of time that supplemental oxygen should be continued postoperatively.

Considering the substantial costlinesss associated with SSIs and the finding that there is barely minor, if any, additional price required to use 80% oxygen supplemental oxygen administered during surgery and a short recuperation period using a nonrebreathing mask can be implemented easily on perioperative personnel. Implementing such a proces carries with it the potential for significantly reducing the incidence of SSIs and positively affecting the documented weighty expense of SSIs.