Research Article: Evaluation of total oxidant and antioxidant status in dogs under different CO2 pneumoperitoneum conditions

Date Published: May 8, 2015

Publisher: BioMed Central

Author(s): Jae Yeon Lee, Seok Hwa Choi.

http://doi.org/10.1186/s13028-015-0113-3

Abstract

The induction of the pneumoperitoneum increases intraabdominal pressure (IAP), causing splanchnic ischemia, whereas its deflation normalizes IAP and splanchnic blood flow. We investigated the oxidant-antioxidant status of dogs who underwent low pressure (7 mm Hg), standard pressure (12 mm Hg), and high pressure (15 mm Hg) pneumoperitoneum.

Twenty-four beagle dogs (12 males and 12 females), 4–6 years old, weighing 8–11 kg were used. The animals were assigned to one of four groups (n = 6 dogs). Group 1 served as a control; these animals received only anaesthesia for 90 min. In groups 2, 3 and 4, intra-abdominal pressure was increased to 7, 12 and 15 mmHg, respectively, and maintained for 60 min. Total oxidant status (TOS) and total antioxidant status (TAS) were determined in venous blood samples. The percentage ratio of TOS to TAS provided an oxidative stress index (OSI).

A high pressure pneumoperitoneum induced significant changes in TAS and OSI. In addition, TOS and TAS levels are useful markers for evaluating changes in the oxidative status caused by a pneumoperitoneum during laparoscopy. Furthermore, a low-pressure pneumoperitoneum could attenuate oxidative stress induced by CO2 insufflation in dogs.

Partial Text

A pneumoperitoneum is generally established during a laparoscopy by continuous insufflation of carbon dioxide (CO2) into the peritoneal cavity to provide adequate visualization and exposure of structures. Laparoscopic surgery has many advantages for the patient compared to conventional surgery, including smaller incisions, less postoperative pain, faster discharge, and a better cosmetic effect [1,2]. However, despite its benefit, a CO2 pneumoperitoneum is not free of adverse events. Oxidative stress is the general phenomenon of oxidant exposure and antioxidant depletion, or oxidant-antioxidant imbalance. Over the last several decades, it has become evident that oxidative stress, usually in the form of reactive oxygen species (ROS), is produced during metabolic and physiological processes [3,4]. Oxidative stress can be quantified by measuring the levels of total antioxidant capacity. Total oxidant status (TOS) and total antioxidant status (TAS) are often used to estimate the overall antioxidant status [5,6].

All dogs were hemodynamically stable throughout the procedure and completed the study. There were no significant worsening in heart rate, mean arterial pressure, rectal temperature, end-tidal carbon dioxide, peripheral oxygen saturation, and respiratory rates (Table 1). The plasma TOS, TAS, and OSI are shown in Figure 1. Increases in plasma TOS and OSI levels, and a decrease in TAS levels were observed in group 2, 3, and 4 after creating the pneumoperitoneum. No significant difference in TOS levels was observed within groups or among the groups, but significant changes in the plasma TAS and OSI levels were observed within group 4. In group 4, the TAS levels at T3 and T4 were significantly decreased from T0 (p = 0.029). In group 4, the OSI levels at T3 and T4 were significantly increased from T0 (p = 0.029). No differences in TOS, TAS and OSI levels were found when the groups were compared.Table 1Heart rate (HR), mean arterial pressure (MAP), rectal temperature (RT), respiratory rate (RR), saturation of peripheral oxygen (SpO2) and end-tidal CO2(ETCO2) in dogsParameterGroupPre (t0)15 min30 min (t1)45 min60 min (t2)90 min (t3)HR (breath/min)Group 1110.0 ± 14.3113.4 ± 16.9115.6 ± 15.3114.4 ± 15.9111.5 ± 16.3115.4 ± 20.9Group 2117.5 ± 11.9119.5 ± 15.7119.5 ± 17.6123.8 ± 10.0128.8 ± 14.1125.9 ± 16.0Group 3120.5 ± 10.5121.3 ± 17.2122.3 ± 19.1124.2 ± 19.5120.3 ± 15.5127.6 ± 17.3Group 4117.7 ± 16.1120.5 ± 10.8122.3 ± 10.2121.2 ± 18.3120.5 ± 15.3125.2 ± 11.3MAP (mmHg)Group 185.8 ± 9.588.5 ± 5.990.0 ± 10.091.8 ± 12.988.9 ± 8.990.5 ± 15.0Group 287.7 ± 6.586. 5 ± 9.986.0 ± 11.087.8 ± 17.087. 5 ± 6.588. 5 ± 9.3Group 385.8 ± 7.588.5 ± 5.985.0 ± 15.086.4 ± 15.187.5 ± 5.688.5 ± 15.9Group 483.4 ± 10.584.5 ± 11.982.0 ± 9.080.5 ± 11.984.3 ± 15.985.5 ± 16.9RT (°C)Group 138.7 ± 1.438.6 ± 1.438.6 ± 1.438.5 ± 1.437.6 ± 0.437.5 ± 1.4Group 238.5 ± 0.438.4 ± 0.838.4 ± 0.838.4 ± 0.837.3 ± 1.837.4 ± 1.2Group 337.7 ± 1.137.6 ± 1.237.5 ± 1.537.5 ± 1.537.2 ± 1.837.0 ± 1.0Group 437.5 ± 1.637.5 ± 1.437.4 ± 1.637.4 ± 0.937.0 ± 1.937.2 ± 1.5RR (breath/min)Group 110.0 ± 4.3413.4 ± 6.9915.6 ± 5.3214.4 ± 5.9416.4 ± 5.9413.5 ± 6.12Group 217.5 ± 11.9819.5 ± 5.7219.5 ± 7.6923.8 ± 10.0520.8 ± 15.1125.6 ± 11.04Group 320.5 ± 10.5621.3 ± 7.2322.3 ± 9.1824.2 ± 9.5425.2 ± 5.5426.3 ± 7.34Group 417.7 ± 6.1920.5 ± 10.8022.3 ± 10.2521.2 ± 8.3825.4 ± 7.6826.2 ± 9.14ETCO2 (mmHg)Group 142.3 ± 5.1448.0 ± 5.3744.8 ± 5.3445.8 ± 4.8844.7 ± 5.8645.7 ± 3.21Group 241.5 ± 2.7351.2 ± 8.1351.5 ± 9.0346.5 ± 4.6444.6 ± 5.7445.5 ± 6.34Group 341.3 ± 12.4047.5 ± 7.2352.0 ± 9.4051.3 ± 8.1451.3 ± 8.1453.3 ± 5.14Group 442.1 ± 13.9055.5 ± 8.8756.8 ± 6.8953.8 ± 6.2850.8 ± 9.2850.5 ± 7.28SpO2 (%)Group 1100 ± 0100 ± 0100 ± 0100 ± 0100 ± 0100 ± 0Group 2100 ± 0100 ± 0100 ± 0100 ± 0100 ± 0100 ± 0Group 3100 ± 0100 ± 0100 ± 0100 ± 0100 ± 0100 ± 0Group 4100 ± 0100 ± 0100 ± 0100 ± 0100 ± 0100 ± 0The values represent the mean ± SD (n = 6).Variables were measured before induction of anesthesia (pre) and at 15, 30, 45, 60, and 90 minutes after induction of anesthesia. T0: before induction of anesthesia; T1: at 30 minutes after pneumoperitoneum; T2: at the end of the pneumoperitoneum and ischemia but before deflation; T3: 30 minutes after deflation.Figure 1Plasma levels of oxidative stress parameters in dogs. The values represent the mean ± SD (n = 6). *Statistically difference compared to baseline values.TOS: total oxidant status, TAS: total antioxidant status, OSI: oxidative stress index, T0: before induction of anesthesia; T1: at 30 minutes after pneumoperitoneum; T2: at the end of the pneumoperitoneum and ischemia but before deflation; T3: 30 minutes after deflation; T4: 24 hours after deflaztion.

Laparoscopic surgeries are increasingly performed in veterinary clinics. However, the possible unwanted side effects of these procedures remain unclear. This study showed that at an IAP of 15 mm Hg there were significant changes in TAS and OSI whereas no significant changes were observed in theses parameters at 0, 7 or 12 mm Hg.

A CO2 pneumoperitoneum induced changes in total oxidant and antioxidant status of dogs in this study. In addition, the results showed that low insufflation pressure during a CO2 pneumoperitoneum tended to produce less oxidative stress compared with standard or high insufflaton pressure, although these differences did not reach statistical significance. Further investigation is needed to evaluate the clinical outcome in patients with a CO2 pneumoperitoneum undergoing laparoscopic surgery.

 

Source:

http://doi.org/10.1186/s13028-015-0113-3