-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
1/22
SUPPLEMENTAL OXYGEN FOR THEPREVENTION OF POSTCESAREAN
INFECTIOUS MORBIDITY: A
RANDOMIZED CONTROLLED TRIAL
Christina M. Scifre MD et al
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
2/22
Background
Perioperative oxygen therapy could reduce therisk of postoperative infection
Oxidative killing mechanism for the
bactericidal activity of neutrophils depend on thepropduction of bactericidal superoxide radicalsfrom molecular oxygen
Leukocyte ba cteial killing capacity is impaired atthe low oxygen tension often found in woundsand perioperative arterial
Wound oxygen tension can be increased by ahigher fraction of inspired O2 (FiO2)
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
3/22
Objective
to investigate whether supplemental oxygen
during and for 2 hours after cesarean delivery
reduces the incidence of postcesareaninfectious morbidity
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
4/22
Objective
Primar outcome measure: SSI wound
infection & endometritis
Hypothesis: supplying 10L of O2 by face mask
during & for 2 hours after CS would reduce
the frequency of surgical site infection
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
5/22
Method
Randomized controlled trial of supplemental
oxygen for the prevention of postcesarean
delivery infectious morbidity at WashingtonUniversity in St. Louis, MO
Institutional review board approval was
obtained before patient enrollment, and
written informed consent was obtained fromall participants.
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
6/22
Method
INCLUSION: underwent scheduled or intrapartum cesarean
delivery with regional anesthesia
EXCLUSION: Emergency surgery in which the participant was
unable to provide informed consent, HIV, chronic CST
Other immunosuppressive therapy, general
anesthesia, and a diagnosis of extrauterine infection(ie, pyelonephritis or pneumonia) before cesareandelivery.
Patients who unexpectedly required GA/ deliveredvaginally after randomization
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
7/22
Method
Written consent obtained
Random assignment of patients in a 1:1
scheme (supplemental O2 group: standardcare group)
Randomization achieved with opaque
envelopes that contained the assigned study
group opened after the patients had agreedto participate in the study before the surgery
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
8/22
Method
SUPPLEMENTAL O2GRP O2 at 10 L/min (FiO2 of
80%) by nonbreathermask during and afterCS
Assessed by ananesthesiologist and by
the postpartum nurse at30, 60, 90, 120 minutesafter surgery
STANDARD CAREGROUP O2 at 2 L/min (FiO2 of
25-20%) by nasalcannula during the CSdelivery only
O2 sat was assessed both intraop and postop for bothgroups
If with O2 sat of
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
9/22
Method
Standard preop skin prep and prophylaticanbtibiotics were given to both groups
Cefazolin as primary preop prophylaxis
Clindamycin used for patients with penicillinallergy
Subq depth was measured by the primaryoperative team with sterile ruler; demographic
intrapartum and operative information wasabstracted from the medical records Operative decision to place subq sutures was left
to the surgical team
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
10/22
Method
Diagnostic criteria for infectious outcome(endometritis) Oral temp >38 C after the first 24 hrs ffg the procedure
Fundal or lower abdominal tenderness greater thanexpected
Foul smelling/ purulent lochia
Endometritis was diagnosed only if other causesfor the patients signs & symptoms were notidentified
Treated with IV antibiotics
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
11/22
Method
Diagnostic criteria for infectious outcome
(wound infection)
Wound opening >1 cm or other surgicalintervention (lap, debdridement)
Plus (at least 1 of the ffg)
Purulent drainage from the wound
Erythema or induration of the surrounding tissues Maternal oral temp >38 C
Radiographic evidence of infection
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
12/22
Method
Pre-identified secondary outcomes:
Wound opening >1cm because of wound
hematoma or seroma Hospital readmission
Need for IV antibiotics after the first 24 hours afterthe procedure
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
13/22
Method
Medical records reviewed at the time of the
2-4 week postop visit
If unable to return telephone inquiry by researchnurse
Data collection form was used as prompt duringthe telephone interviews to ensure
standardization
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
14/22
Method
Primary comparison of the study was
supplemental O2 vs standard care with
respect to primary outcome of infectiousmorbidity
Data was analyzed using unpaired t tests for
normally distributed continous variables,
Mann-Whitney U test for normally distributedcontinous variables, Chi-squared/ Fishersexact tests for categoric data
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
15/22
Method
P value of
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
16/22
Results
Feb 2008 Mar 2010
21 were excluded
13 GA 6 vaginal delivery
1 extrauterine infection
1 prev enrolled in a conflicting study
7 were in the standard care group
14 were in the supplemental O2 group
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
17/22
Results
585 were included in the final analysis
535 (91.5%) received their alloted study treatment
6 (2.1%) lost to follow up 63/297 (21.2%) standard care group =
70/ 288 (24.3) supplemental O2 group = telephoneinterview
Additional O2 to maintain O2 sat of 95% wasrequired in 18 subjects
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
18/22
FIGURETrial recruitment and flowNC, nasal cannula; NRBM, non-rebreather mask.Scifres. Supplemental oxygen for the prevention of postcesarean infection. Am J ObstetGynecol 2011.
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
19/22
Results
Similarity of study groups were observed in
terms of large nuber of clinical variables:
maternal age, AOG at delivery, BMI, subqdepth, maternal DM, Grp B strep perineal
colonization, surgical blood loss, prophylactic
antibiotic use, timing of administration of
antibiotics
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
20/22
Variable Standard care (n = 297) Supplemental oxygen (n
= 288)
P value
Maternal age, ya
27.85.9 27.56.4 .48
Gravity, na
3.11.8 3.01.7 .23
Gestational age, wka
37.82.5 37.53.2 .18
Race, n (%) .93
White 92(30.1) 93(32.3)
Black 186(62.6) 176(61.1)
Other 19(6.4) 19(6.6)
Insurance, n (%) .65
Public 190(64.0) 190(66.0)Private 91(30.6) 87(30.2)
None 16(5.4) 11(3.8)
Smoking, n (%) 50(16.8) 37(12.9) .18
Illicit drug use, n (%) 12(4) 11(3.8) .89
Preterm delivery, n (%) .87
30 kg/m2) 230(77.44) 208(72.22)
Subcutaneous depth,
cma
2.611.58 2.671.50 .63
Chronic hypertension, n
(%)
21(7.1) 34(11.8) .05
TABLE 1 Characteristics
of participants by study
assignment
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
21/22
TABLE 1 Characteristics
of participants by study
assignment
Pregnancy-inducedhypertension, n (%)
43(14.5) 57(19.8) .09
Diabetes mellitus, n (%)
Pregestational 13(4.4) 17(5.9) .40
Gestational 19(6.4) 20(6.9) .79
Asthma, n (%) 51(17.2) 38(13.2) .18
Previous abdominalsurgery that includedcesarean section,
laparoscopy, laparotomy,n (%)
210(70.7) 181(62.9) .04
Preoperativehemoglobin, g/dL
a11.51.45 11.41.37 .66
Multiple gestation, n (%) .35
Singleton 276(92.93) 260(92.6)
Twin 21(7.1) 27(9.4)
Triplet 0 1(0.4)
Labor before cesarean
delivery, n (%)
97(32.7) 115(40.0) .07
Hours in labora
16.48.5 14.59.6 .50
GroupB streptococcuspositive, n(%)
.99
Yes 68(22.9) 67(23.3)
No 238(46.5) 132(45.8)
Unknown
-
8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious
22/22
Results
Infectious morbidity developed ibn 10.4% of
participants (8.8% in standard care group;
12.2% in supplemental O2 group No significant difference in incidence of
wound nfection or endometritis
No difference in wound complication orhospital readmission rate