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Table 3 The factors affecting bacterial counts in operating rooms using linear regression analysis

From: Factors influencing microbial colonies in the air of operating rooms

Variables Pearson Correlation Pearson Correlation p -value Regression Coefficients Regression Coefficients Standard Error Regression Coefficients 95% CI* Regression p-value
Surgery time# (hour) −.005 .470 −1.72 2.30 −6.25-2.80 .453
Surgery schedules (urgent surgery/regular surgery) .093 .071 3.66 8.57 −13.21-20.54 .669
Type of surgery (pediatric surgery / adult surgery) .153 .008 29.85 14.50 1.28–58.42 .041
Site of procedure (deep incision and organ/space / superficial incision) .164 .005 20.19 6.07 8.24–32.14 .001
Wound classification (contaminated and dirty/ clean and clean-contaminated) .021 .368 4.82 6.62 −8.23-17.87 .467
Indoor air temperature (°C) .104 .051 9.40 3.95 1.61–17.18 .018
Indoor air relative humidity (%) .001 .499 1.32 .81 −0.27-2.91 .104
Number of indoor staff (n) .217 <.001 4.93 1.75 1.47–8.38 .005
Frequency of operating room door opening during a surgical procedure (n) .109 .043 7.28 3.77 −0.15-14.70 .055
Sequence of the operation during the day .065 .154 2.21 2.13 −2.00-6.41 .302
Time of sampling .052 .205 3.65 4.45 −5.13-12.42 .413
Surgical staging (before incision and after wound closure /during incision to wound closure) .346 <.001 36.50 5.96 24.76–48.25 <.001
  1. *CI Confidence Interval; #Surgery time = during incision to wound closure