Supplemental Oxygen for the Prevention of Post Cesarean Infectious

8/3/2019 Supplemental Oxygen for the Prevention of Post Cesarean Infectious

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SUPPLEMENTAL OXYGEN FOR THEPREVENTION OF POSTCESAREAN

INFECTIOUS MORBIDITY: A

RANDOMIZED CONTROLLED TRIAL

Christina M. Scifre MD et al


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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)


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Objective

to investigate whether supplemental oxygen

during and for 2 hours after cesarean delivery

reduces the incidence of postcesareaninfectious morbidity


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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


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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.


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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


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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


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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


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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


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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


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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


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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


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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


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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


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Method

P value of


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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


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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


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FIGURETrial recruitment and flowNC, nasal cannula; NRBM, non-rebreather mask.Scifres. Supplemental oxygen for the prevention of postcesarean infection. Am J ObstetGynecol 2011.


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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


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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


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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


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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

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Supplemental Oxygen for the Prevention of Post Cesarean Infectious