AIM:To compare the reliability and plaque area between using high-cholesterol diet and high-cho-lesterol diet with corn oil to establish a rabbit atherosclerotic model .METHODS:Eighteen New Zealand rabbits were ran-domly divided into 3 groups (6 rabbits each):normal diet group (group C), high-cholesterol diet group (group H1) and high-cholesterol diet containing 6%corn oil group (group H2).All rabbits were fed for 12 weeks, and their body mea-sured was weighed at the end of every weeks .The serum levels of high-density lipoprotein cholesterol ( HDL-C) , low-den-sity lipoprotein cholesterol ( LDL-C) , total cholesterol ( TC) and triglyceride ( TG) were measured by automatic chemistry analyzer at 0 week and 12 weeks.At the end of 12 weeks, the thoracic aorta of 8-cm length since aortic root was isolated from the rabbit after anesthesia , and stained with Sudan IV or oil red O to verify the existence of plaque .The percentage of plaque area (PA/IA) in the intima area was further calculated by ImageJ 2x software.RESULTS:At the end of 12-week feeding, the serum levels of HDL-C, LDL-C and TC in both group H1 and group H2 were significantly higher than those in group C, and serum TG in group H2 was significantly higher than that in group C .Serum HDL-C in group H2 was signifi-cantly higher than that in group H1, but no significant difference of serum LDL-C, TC and TG between group H1 and group H2 was found .There was no plaque in the intima in group C , and plaques were observed in the intima of all rabbits in group H1 and group H2.Rabbit atherosclerotic models in both group H 1 and group H2 were established with a success rate of 100%.The values of PA/IA in group H1 [(49.74 ±18.78)%] and group H2 [(56.95 ±26.74)%] were both sig-nificantly higher than that in group C (0%), and no significant difference of PA/IA between group H1 and group H2 was observed.CONCLUSION:High-cholesterol diet with or without corn oil can establish a rabbit atherosclerotic model with a success rate of 100%after 12-week feeding , and the percentage of plaque area in the total aortic intimal area is not differ-ent in the 2 feeding methods .

Objective:After general anesthesia and mechanical ventilation for laparoscopic colorectal cancer resection, about 90% of patients would have different degrees of atelectasis. Authors speculated that an open-lung strategy (OLS) comprising moderate positive end-expiratory pressure (PEEP) and intermittent recruitment maneuvers (RM) can reduce atelectrauma and thus reduce the incidence of oxygenation-impairment during low-tidal-volume ventilation for laparoscopic colorectal cancer resection. The purpose of this study was to verify this hypothesis and provide a better intraoperative ventilation scheme for laparoscopic colorectal cancer resection.Methods:This was a prospectively randomized controlled clinical trial which was approved by the Ethics Committee of the Sixth Affiliated Hospital, Sun Yat-sen University (2017ZSLYEC-002), and registered at the ClinicalTrials.gov (NCT03160144). From January to July 2017, patients who underwent laparoscopic colorectal cancer resection, with age > 40 years, estimated pneumoperitoneum time ≥ 1.5 h, pulse oxygen saturation ≥ 92%, and risk grade for postoperative pulmonary complications ≥ 2 were prospectively enrolled. The patients with American Society of Anesthesiologists physical status ≥ IV, body mass index ≥ 30 kg/m 2, pneumonia, acute respiratory failure or sepsis within 1 month, severe chronic obstructive pulmonary disease, pulmonary bullae and progressive neuromuscular diseases, and those participating in other interventional clinical trials were excluded. The enrolled patients were randomly assigned (1:1) to the OLS group (with a PEEP of 6-8 cm H 2O and intermittent RM), and the NOLS group (without using PEEP and RM). Partial pressure of arterial oxygen (PaO 2) /fraction of inspired oxygen (FiO 2) and shunt fraction (Q S/Q T) were calculated via arterial and central venous blood gas analysis performed at 0.5 h (T 1), 1.5 h (T 2) after pneumoperitoneum induction and at 20 min after admission to the recovery room. Driving pressure immediately before pneumoperitoneum induction (T 0) and at T 2 were calculated via monitoring data. The primary outcome was oxygenation-impairment (PaO 2/FiO 2 ≤ 300 mmHg) during mechanical ventilation. Results:In each group, 48 patients under general anesthesia and low-tidal-volume ventilation were included in the final analysis. During ventilation, the oxygenation-impairment occurred in 7 patients (14.6%) of OLS group and in 17 patients (35.4%) of NOLS group, whose difference was statistically significant between two groups (χ 2=5.556, RR=0.31, 95%CI: 0.12 to 0.84, P=0.033). During ventilation, the patients in the OLS group had higher PaO 2/FiO 2 [T 1: (427±103) mmHg vs. (366±109) mmHg, t=-2.826, P=0.006; T 2: (453±103) mmHg vs. (388±122) mmHg, t=-2.739, P=0.007], lower Q S/Q T [ T 1: (9.2±6.5) % vs. (12.6±7.7) %, t=2.322, P=0.022; T 2: (7.0±5.8)% vs.(10.9±9.2)%, t=2.408, P=0.019], and lower driving pressure [T 0: (6±3) cm H 2O vs. (10±2) cm H 2O, t=7.421, P<0.001; T 2: (13±3) cm H 2O vs. (17±4) cm H 2O, t=5.417, P<0.001] than those in the NOLS group, with stratistical differences in all comparisons. In recovery room, though PaO 2/FiO 2 [(70.3±9.4) mmHg vs. (66.8±9.4) mmHg, P=0.082] was still higher and Q S/Q T [(18.6±8.3)% vs. (21.8±8.4)%, P=0.070] was still lower in the OLS group as compared to the NOLS group, the differences were not statistically significant (both P>0.05). Conclusion:The application of such an OLS during low-tidal-volume ventilation can greatly reduce the incidence of oxygenation-impairment in laparoscopic colorectal cancer resection, and such effect may last to the period of emergence from anesthesia.

Objective:After general anesthesia and mechanical ventilation for laparoscopic colorectal cancer resection, about 90% of patients would have different degrees of atelectasis. Authors speculated that an open-lung strategy (OLS) comprising moderate positive end-expiratory pressure (PEEP) and intermittent recruitment maneuvers (RM) can reduce atelectrauma and thus reduce the incidence of oxygenation-impairment during low-tidal-volume ventilation for laparoscopic colorectal cancer resection. The purpose of this study was to verify this hypothesis and provide a better intraoperative ventilation scheme for laparoscopic colorectal cancer resection.Methods:This was a prospectively randomized controlled clinical trial which was approved by the Ethics Committee of the Sixth Affiliated Hospital, Sun Yat-sen University (2017ZSLYEC-002), and registered at the ClinicalTrials.gov (NCT03160144). From January to July 2017, patients who underwent laparoscopic colorectal cancer resection, with age > 40 years, estimated pneumoperitoneum time ≥ 1.5 h, pulse oxygen saturation ≥ 92%, and risk grade for postoperative pulmonary complications ≥ 2 were prospectively enrolled. The patients with American Society of Anesthesiologists physical status ≥ IV, body mass index ≥ 30 kg/m 2, pneumonia, acute respiratory failure or sepsis within 1 month, severe chronic obstructive pulmonary disease, pulmonary bullae and progressive neuromuscular diseases, and those participating in other interventional clinical trials were excluded. The enrolled patients were randomly assigned (1:1) to the OLS group (with a PEEP of 6-8 cm H 2O and intermittent RM), and the NOLS group (without using PEEP and RM). Partial pressure of arterial oxygen (PaO 2) /fraction of inspired oxygen (FiO 2) and shunt fraction (Q S/Q T) were calculated via arterial and central venous blood gas analysis performed at 0.5 h (T 1), 1.5 h (T 2) after pneumoperitoneum induction and at 20 min after admission to the recovery room. Driving pressure immediately before pneumoperitoneum induction (T 0) and at T 2 were calculated via monitoring data. The primary outcome was oxygenation-impairment (PaO 2/FiO 2 ≤ 300 mmHg) during mechanical ventilation. Results:In each group, 48 patients under general anesthesia and low-tidal-volume ventilation were included in the final analysis. During ventilation, the oxygenation-impairment occurred in 7 patients (14.6%) of OLS group and in 17 patients (35.4%) of NOLS group, whose difference was statistically significant between two groups (χ 2=5.556, RR=0.31, 95%CI: 0.12 to 0.84, P=0.033). During ventilation, the patients in the OLS group had higher PaO 2/FiO 2 [T 1: (427±103) mmHg vs. (366±109) mmHg, t=-2.826, P=0.006; T 2: (453±103) mmHg vs. (388±122) mmHg, t=-2.739, P=0.007], lower Q S/Q T [ T 1: (9.2±6.5) % vs. (12.6±7.7) %, t=2.322, P=0.022; T 2: (7.0±5.8)% vs.(10.9±9.2)%, t=2.408, P=0.019], and lower driving pressure [T 0: (6±3) cm H 2O vs. (10±2) cm H 2O, t=7.421, P<0.001; T 2: (13±3) cm H 2O vs. (17±4) cm H 2O, t=5.417, P<0.001] than those in the NOLS group, with stratistical differences in all comparisons. In recovery room, though PaO 2/FiO 2 [(70.3±9.4) mmHg vs. (66.8±9.4) mmHg, P=0.082] was still higher and Q S/Q T [(18.6±8.3)% vs. (21.8±8.4)%, P=0.070] was still lower in the OLS group as compared to the NOLS group, the differences were not statistically significant (both P>0.05). Conclusion:The application of such an OLS during low-tidal-volume ventilation can greatly reduce the incidence of oxygenation-impairment in laparoscopic colorectal cancer resection, and such effect may last to the period of emergence from anesthesia.

BACKGROUNDThe protective effects of transient limb ischemia (TLI) induced by several cycles of intermittent pressure cuff inflation and deflation for a period have been widely investigated, however the reliability of this protocol has not been clearly verified. Our study aimed to investigate the reliability of pressure cuff induced TLI in conscious rabbits.

METHODSEight New Zealand rabbits were subjected to TLI without anesthesia. TLI consisted of 3 cycles of ischemia and reperfusion induced by inflating the cuff placed on the left lower limb to 200 mmHg for 5 minutes followed by deflating the cuff for 5 minutes. Skin color, pulse oxygen saturation (SpO2), pulse rate (PR), plethysmogram waveform (Pleth), and ultrasound detection of the blood flow in the extremity distal to the ischemic segment were observed to confirm ischemia and reperfusion during TLI. The frequency of severe limb movement during TLI was also recorded to assess the amenability of this protocol in conscious rabbits.

RESULTSThe skin color of the extremity distal to the ischemic segment changed from bright red to dark purple after inflating the cuff to 200 mmHg, and returned to normal after cuff deflation. Pleth, PR and SpO2 disappeared during ischemia and restored during reperfusion in the monitor. Blood flow of the left posterior tibial artery was completely blocked by a pressure of 200 mmHg during ischemia, and recovered immediately after cuff deflation. The frequency of severe limb movement in supine position was higher than that in prone position (P < 0.05), but there was no severe limb movement that could result in disturbance to ischemia when the rabbits were placed in prone position.

CONCLUSIONPressure cuff inflating to 200 mmHg for 5 minutes and deflating for 5 minutes is a reliable regimen to induce TLI in conscious rabbits.

Animals ; Disease Models, Animal ; Extremities ; pathology ; Ischemia ; etiology ; pathology ; Ischemic Preconditioning ; Male ; Rabbits

OBJECTIVE: To investigate the perioperative electrolyte imbalance in patients undergoing gastrointestinal surgery. METHODS: Retrospective case analysis was used in this study. Patients who underwent gastrointestinal surgery under general anesthesia at the Sixth Affiliated Hospital of Sun Yat-sen University from January to April 2018 were selected through electronic medical records system. Blood gas analysis during surgery must be carried out in the enrolled patients. Patients with excessive fluid infusion, critical conditions or patients who had been enrolled in other clinical trials were excluded. A total of 999 patients were enrolled. The preoperative, intraoperative and postoperative concentrations of serum sodium, potassium and calcium were collected by the last biochemical examination before surgery, arterial blood gas analysis within 1 h after anesthesia and another biochemical examination within 24 hours after surgery respectively. The type and incidence of electrolyte imbalance were then analyzed, and logistic regression analysis was used to investigate the risk factors. RESULTS: In the 999 patients, 683 cases were male (63.9%) and 361 cases were female(36.1%), with an average age of (56.9±14.6) years old. Fifty-eight patients (5.8%) underwent emergency surgery and 941 patients (94.2%) underwent elective surgery; Sixty-two patients were treated with laxatives at least 3 times and 115 patients were treated with enema at least 3 times before operation. The incidence of hypokalemia was 49.6%(496/999) intraoperatively and decreased to 15.2%(152/999) postoperatively. No hyperkalemia cases were found. The incidence of hypocalcemia was 53.8%(537/999) intraoperatively and increased to 79.7% (796/999) postoperatively. The incidence of hypokalemia in ileus patients was 33.3%(17/51) before surgery, which was higher than that in patients with colorectal cancer [12.3%(86/703)], patients with gastric cancer [7.8%(8/104)] and patients with other gastrointestinal diseases[10.6%(15/141)] (all P<0.05). Similarly, the preoperative and intraoperative incidence of hyponatremia in ileus patients were both 15.7%(8/51), which were higher than those in patients with colorectal cancer [3.0% (21/703) and 2.3% (16/703)] and patients with gastric cancer [2.9%(3/104) and 1.9%(2/104)]. The incidence of hypocalcemia in ileus patients was 31.4%(16/51) preoperatively, which were also higher than those in patients with colorectal cancer [7.4%(52/703)] and patients with gastric cancer [8.7%(9/104)] (all P<0.05). Logistic regression analysis showed that ileus and emergency surgery were risk factors for patients with preoperative electrolyte imbalance; preoperative electrolyte imbalance was a risk factor for intraoperative electrolyte imbalance; intraoperative electrolyte imbalance was a risk factor for postoperative electrolyte imbalance; preoperative electrolyte imbalance was a risk factor for postoperative imbalance of sodium and potassium. CONCLUSIONS The incidence of electrolyte imbalance is high in patients undergoing gastrointestinal surgery, especially hypocalcemia and hypokalemia. It is necessary to recognize the electrolyte abnormality timely and give active intervention and correction.
Adult ; Aged ; Digestive System Surgical Procedures ; Electrolytes ; Female ; Humans ; Hyponatremia ; Ileus ; Male ; Middle Aged ; Postoperative Complications ; prevention & control ; Retrospective Studies ; Risk Factors ; Water-Electrolyte Imbalance