Fig 1.
Flow chart of study selection process.
The number of studies in each phase is indicated in bold font. OMs = outcome measures; CO = separate control group; ΔBL = repeated measures design comparing data during pneumoperitoneum with control measurements taken at baseline in the same animals.
Table 1.
Primary study characteristics.
Fig 2.
Risk of bias and quality assessment.
Poor reporting of key study quality indicators (A) resulted in an unclear risk of bias for most types of bias (B). In some studies, unexplained drop-outs, and the absence of a Veress needle in the control group, led to a high risk of respectively attrition (item #9) and other biases (item #10). n/a = reporting of randomization (panel A) and items on selection bias (#1–3) and blinding of the intervention (item #5; panel B) were not applicable to Δ baseline studies.
Fig 3.
Serum creatinine is increased during pneumoperitoneum compared to baseline.
Forest plot of studies comparing serum creatinine during pneumoperitoneum with baseline measurements in the same animals. Effect size is calculated as mean difference (MD) in serum creatinine in mg/dl, and corresponding 95% confidence intervals (95%CI). Weights are from random effects analysis. m = duration of PnP in minutes at time of measurement.
Fig 4.
Serum creatinine is increased during pneumoperitoneum compared to controls.
Forest plot of studies comparing serum creatinine in animals undergoing pneumoperitoneum with control animals. Effect size is calculated as mean difference (MD) in serum creatinine in mg/dl, and corresponding 95% confidence intervals (95%CI). Weights are from random effects analysis. mmHg = pressure in experimental group; CO2 = insufflation with carbon dioxide; He = insufflation with helium; m = duration in minutes of PnP at time of measurement.
Table 2.
Subgroup analysis serum creatinine.
Fig 5.
Renal blood flow is decreased during pneumoperitoneum compared to baseline.
Forest plot of studies comparing renal blood flow during pneumoperitoneum with baseline measurements in the same animals. Effect size is calculated as standardized mean difference (SMD) in renal blood flow, and corresponding 95% confidence intervals (95%CI). Weights are from random effects analysis. *baseline measurements during laparotomy; retro = retroperitoneum applied; m = duration in minutes of PnP at time of measurement; mmHg = pressure in experimental group; CO2 = insufflation with carbon dioxide; He = insufflation with helium; RCBF = renal cortical blood flow; RMBF = renal medullary blood flow.
Fig 6.
Renal blood flow is decreased during pneumoperitoneum compared to controls.
Forest plot of studies comparing renal blood flow in animals undergoing pneumoperitoneum with control animals. Effect size is calculated as standardized mean difference (SMD) in renal blood flow, and corresponding 95% confidence intervals (95%CI). Weights are from random effects analysis. m = duration in minutes of PnP at time of measurement; mmHg = pressure in experimental group.
Table 3.
Subgroup analysis renal blood flow.
Fig 7.
Urine output is decreased during pneumoperitoneum compared to baseline.
Forest plot of studies comparing urine output during pneumoperitoneum with baseline measurements in the same animals. Effect size is calculated as standardized mean difference (SMD) in urine output, and corresponding 95% confidence intervals (95%CI). Weights are from random effects analysis. mmHg = pressure in experimental group; m = duration in minutes of PnP at time of measurement; He = insufflation with helium; CO2 = insufflation with carbon dioxide; retro = retroperitoneum applied.
Fig 8.
Urine output is decreased during pneumoperitoneum compared to controls.
Forest plot of studies comparing urine output in animals undergoing pneumoperitoneum with control animals. Effect size is calculated as standardized mean difference (SMD) in urine output, and corresponding 95% confidence intervals (95%CI). Weights are from random effects analysis. mmHg = pressure in experimental group; He = insufflation with helium; CO2 = insufflation with carbon dioxide; m = duration in minutes of PnP at time of measurement.
Table 4.
Subgroup analysis urine output.