Modulation of angiopoietin-2 and Tie2: Organ specific effects of microvascular leakage and edema in mice.

INTRODUCTION: Critical illness is associated with organ failure, in which endothelial hyperpermeability and tissue edema play a major role. The endothelial angiopoietin/Tie2 system, a regulator of endothelial permeability, is dysbalanced during critical illness. Elevated circulating angiopoietin-2 and decreased Tie2 receptor levels are reported, but it remains unclear whether they cause edema independent of other critical illness-associated alterations. Therefore, we have studied the effect of angiopoietin-2 administration and/or reduced Tie2 expression on microvascular leakage and edema under normal conditions. METHODS: Transgenic male mice with partial deletion of Tie2 (heterozygous exon 9 deletion, Tie2+/-) and wild-type controls (Tie2+/+) received 24 or 72 pg/g angiopoietin-2 or PBS as control (n = 12 per group) intravenously. Microvascular leakage and edema were determined by Evans blue dye (EBD) extravasation and wet-to-dry weight ratio, respectively, in lungs and kidneys. Expression of molecules related to endothelial angiopoietin/Tie2 signaling were determined by ELISA and RT-qPCR. RESULTS: In Tie2+/+ mice, angiopoietin-2 administration increased EBD extravasation (154 %, p < 0.05) and wet-to-dry weight ratio (133 %, p < 0.01) in lungs, but not in the kidney compared to PBS. Tie2+/- mice had higher pulmonary (143 %, p < 0.001), but not renal EBD extravasation, compared to wild-type control mice, whereas a more pronounced wet-to-dry weight ratio was observed in lungs (155 %, p < 0.0001), in contrast to a minor higher wet-to-dry weight ratio in kidneys (106 %, p < 0.05). Angiopoietin-2 administration to Tie2+/- mice did not further increase pulmonary EBD extravasation, pulmonary wet-to-dry weight ratio, or renal wet-to-dry weight ratio. Interestingly, angiopoietin-2 administration resulted in an increased renal EBD extravasation in Tie2+/- mice compared to Tie2+/- mice receiving PBS. Both angiopoietin-2 administration and partial deletion of Tie2 did not affect circulating angiopoietin-1, soluble Tie2, VEGF and NGAL as well as gene expression of angiopoietin-1, -2, Tie1, VE-PTP, ELF-1, Ets-1, KLF2, GATA3, MMP14, Runx1, VE-cadherin, VEGFα and NGAL, except for gene and protein expression of Tie2, which was decreased in Tie2+/- mice compared to Tie2+/+ mice. CONCLUSIONS: In mice, the microvasculature of the lungs is more vulnerable to angiopoietin-2 and partial deletion of Tie2 compared to those in the kidneys with respect to microvascular leakage and edema.

Changes in colloid oncotic pressure during cardiac surgery with different prime fluid strategies.

OBJECTIVE: In cardiac surgery, colloid oncotic pressure (COP) is affected by haemodilution that results from composition and volume of prime fluid of cardiopulmonary bypass (CPB). However, the extent to which different priming strategies alter COP is largely unknown. Therefore, we investigated the effect of different priming strategies on COP in on-pump cardiac surgery. METHODS: Patients (n = 60) were divided into 3 groups (n = 20 each), based on the center in which they were operated and the specific prime fluid strategy used in that center during the inclusion period. CPB prime fluids were either gelofusine-, albumin-, or crystalloid based, the latter two with or without retrograde autologous priming. RESULTS: In all groups, COP was lowest after weaning from CPB and one hour after CPB. Between groups, COP was lowest with gelofusine prime fluid (16.4, 16.8 mmHg, respectively) compared with crystalloids (MD: -1.9; 95% CI:-3.6, -0.2; p = .02 and MD: -2.4, 95% CI: -4.2, -0.7; p = .002) and albumin (MD: -1.8, 95% CI: -3.5, -0.50; p = .041 and MD: -2.4, 95% CI: -4.1, -0.7; p = .002). In all groups, the decrease in COP one hour after bypass compared to baseline correlated positively with fluid balance at the end of surgery (p < .001). CONCLUSIONS: COP significantly decrease during CPB surgery with the largest decrease in COP at the end of surgery, while at the same time fluid balance increases. We suggest that prime fluid strategy should be carefully selected when maintenance of COP during cardiac surgery is desirable.

Safety and efficacy of hyperosmolar irrigation solution in shoulder arthroscopy.

BACKGROUND: A hyperosmolar irrigation solution has been reported to be safe and have potential benefits for use during shoulder arthroscopy in an animal model study. In this study, the clinical effects of a hyperosmolar solution were compared with a standard isotonic solution when used for shoulder arthroscopy. METHODS: A prospective, double-blind, randomized controlled trial was performed to compare isotonic (273 mOsm/L) and hyperosmolar (593 mOsm/L) irrigation solutions used for arthroscopic rotator cuff repair. Primary outcomes focused on the amount of periarticular fluid retention based on net weight gain, change in shoulder girth, and pain. All patients were tracked through standard postsurgical follow-up to ensure no additional complications arose. Patients were contacted at 1 year to assess American Shoulder and Elbow Surgeon score, visual analog scale pain score, and the Single Assessment Numeric Evaluation shoulder scores RESULTS: Fifty patients (n = 25/group) were enrolled and completed the study. No statistically significant differences were noted between cohorts in demographics or surgical variables. The hyperosmolar group experienced significantly less mean weight gain (1.6 ± 0.82 kg vs. 2.25 ± 0.77 kg; P = .005), significantly less change in shoulder girth (P < .05), and a significantly lower immediate postoperative visual analog scale pain score (P = .036). At 1 year postoperatively, the differences between groups for American Shoulder and Elbow Surgeons, visual analog scale pain, and Single Assessment Numeric Evaluation were not significant (P > .2). CONCLUSION: A hyperosmolar irrigation solution provides a safe and effective way to decrease periarticular fluid retention associated with arthroscopic rotator cuff surgery without any adverse long-term effects. Use of a hyperosmolar irrigation solution for shoulder arthroscopy has potential clinical benefits to surgeons and patients.

[Hip arthroscopy after luxatio obturatoria. With contralateral unstable pelvic ring fracture]. / Hüftgelenkarthroskopie nach Luxatio obturatoria. Bei kontralateraler instabiler Beckenringfraktur.

Traumatic dislocation of the hip is a severe injury. Even in cases of an early uncomplicated repositioning there is a high risk of associated intra-articular injuries, such as lesions of the labrum, ruptures of the ligament of the head of the femur and loose bodies. The degree of damage caused by dislocation of the hip becomes apparent with a highly increased risk of developing postinjury osteoarthritis after dislocation of the hip. Some of the major intra-articular damage resulting from hip dislocation, e.g. loose bodies, can be detected by computed tomography and magnetic resonance imaging and can be effectively addressed by hip arthroscopy, thus aiming at reducing the acute symptoms and the risk of postinjury osteoarthritis. The force effect which causes dislocation of the hip can generate severe associated extra-articular injures as in the case described with an unstable fracture of the pelvis. This supplementary injury had to be considered while planning the operative therapy and rehabilitation. A patient presented after a traffic accident with a luxatio obturatoria on the right side and a complex fracture of the left pelvis including the posterior ring and the anterior wall of the acetabulum. After reposition of the right hip and operative therapy of the left side, a loose body was identified in the right hip joint during the computed tomography control of the osteosynthesis. Before patient mobilization extraction of the intra-articular loose body was performed arthroscopically. This was done in consideration of the reduced possibility of distraction due to the osteosynthesis on the contralateral side. Attention was particularly paid to the risk of intra-abdominal fluid extravasation (IAFE). This syndrome is described as a severe complication during hip arthoscopy especially in cases of defects of the hip capsule as assumed after hip dislocation and magnetic resonance imaging.

Short time impact of different hydroxyethyl starch solutions on the mesenteric microcirculation in experimental sepsis in rats.

BACKGROUND: Fluid resuscitation plays a crucial role in the therapy of severe sepsis and septic shock. The use of colloids in sepsis is controversial at present. The aim of our study was to evaluate the effects of second and third generation colloids on the mesenteric microcirculation in early experimental sepsis. METHODS: Male Lewis rats (n=64) were used. Animals underwent sham surgery or colon ascendens stent insertion for sepsis induction by peritonitis. Sixteen hours after the surgery animals were randomly assigned to receive one of the following fluid regimens intravenously: 16ml/kg Ringer's lactate, 64ml/kg Ringer's lactate, 16ml/kg 130/0.4 hydroxyethyl starch, and 16ml/kg 200/0.5 hydroxyethyl starch. Intravital microscopy of the mesenteric microcirculation (plasma extravasation; leukocyte-endothelial interactions) and arterial blood gas analysis were performed before and after fluid resuscitation. RESULTS: In animals with experimental sepsis plasma extravasation was significantly increased compared to control animals (p<0.05). There were no significant differences in plasma extravasation between septic animals receiving crystalloids and or colloid. Furthermore, the type of administered fluid did not influence the number of adhering leucocytes during the observation period. CONCLUSION: The short time impact of different hydroxyethyl starch solutions on the microcirculation of the mesentery is not different from crystalloids in colon ascendens stent peritonitis-induced experimental sepsis in rats.

Intra-abdominal Fluid Extravasation: Is Endoscopic Deep Gluteal Space Exploration a Risk Factor?

BACKGROUND: The extravasation of fluid into the intra-abdominal space is recognized as a possible complication of hip arthroscopic surgery/endoscopy. The exposure of anatomic areas to elevated pump pressures and high volumes of irrigation fluid increases the risk of fluid leakage into anatomic spaces around the hip joint, especially to the abdomen and pelvis. PURPOSE: To estimate the incidence and risk factors related to intra-abdominal fluid extravasation (IAFE) after hip endoscopy or arthroscopic surgery. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A prospective study was carried out between June 2017 and June 2018. A total of 106 hip procedures (endoscopy or arthroscopic surgery) performed for extra- or intra-articular abnormalities were included. Before and after surgery, in the operating room, ultrasound was performed by a trained anesthesiologist to detect IAFE. The hepatorenal (Morison pouch), splenorenal, retroaortic, suprapubic (longitudinal and transverse), and pleural spaces were examined. Patients were monitored for 3 hours after surgery to assess for abdominal pain. The data collected included maximum pump pressure, duration and volume of irrigation fluid (Ringer lactate), total surgical time, and traction time. RESULTS: The incidence of IAFE was 31.1% (33/106; 95% CI, 23.1%-40.5%). The frequency of IAFE was 52.9% (9/17) in cases with isolated extra-articular abnormalities and 15.9% (7/44) in cases with isolated femoroacetabular impingement; in cases with both extra- and intra-articular abnormalities, the frequency was 37.8% (17/45). An intervention in the subgluteal space was identified as a risk factor for IAFE (odds ratio, 3.62 [95% CI, 1.47-8.85]). There was no statistically significant difference between groups (with vs without IAFE) regarding total surgical time, maximum pump pressure, or fluid volume. Postoperative abdominal pain was found in 36.4% (n = 12) of cases with IAFE compared with 2.7% (n = 2) of cases without extravasation (P < .001). No patient with IAFE developed abdominal compartment syndrome. CONCLUSION: IAFE was a frequent finding after hip arthroscopic surgery/endoscopy in patients with extra-articular abnormalities. Exploration of the subgluteal space may increase the risk of IAFE. Pain and abdominal distension during the immediate postoperative period were early warning signs for IAFE. These results reinforce the need for careful intraoperative and postoperative monitoring by the surgeon and anesthesiologist to identify and avoid complications related to IAFE.

Extravasation of fluid in arthroscopic shoulder surgery requiring prolonged intubation: a case report.

BACKGROUND: Shoulder arthroscopy is a safe and effective procedure with a low complication rate. Although rare, there are potentially life-threatening risks such as fluid extravasation causing airway compromise. CASE PRESENTATION: We report the case of a 65-year-old female treated with an arthroscopic rotator cuff repair who had significant extravasation of arthroscopic fluid causing severe facial and neck swelling. Overnight intubation was required for respiratory monitoring until the edema had resolved enough to allow safe extubation. CONCLUSION: This case highlights the risk factors and clinical course of a patient with airway compromise caused by extravasation of fluid during shoulder arthroscopy. Although shoulder arthroscopy is a safe procedure, surgeon familiarity with the risk factors for this complication and close monitoring can aid in its identification and allow for appropriate treatment.

eFAST for the diagnosis of a perioperative complication during percutaneous nephrolithotomy.

A 29-year-old patient with normal preanesthetic evaluation was planned for percutaneous nephrolithotomy (PCNL) for right nephrolithiasis with right pyelolithiasis. Surgery was performed under general anesthesia with endotracheal intubation with muscle relaxation. At the conclusion of surgery, when the patient was turned over to supine position, tense abdomen was noted. Immediately extended focused assessment with sonography in trauma (eFAST) was done in which both right and left quadrants of abdomen including pericardial and suprapubic region, right and left thoracic, and both lung basis were examined. Fluid collection was seen in Morison's pouch which was drained by the urologist under real-time ultrasonography guidance by anesthesiologist. Distension of abdomen subsequently subsided and patient had normal vitals. Trachea was extubated and patient shifted to post-operative ward. eFAST and FAST scans are routine procedures in the rapid assessment of trauma victims in emergency settings. The fluid extravasation during a routine PCNL procedure may lead to abdominal compartment syndrome. This case demonstrated that use of eFAST rapidly detected abdominal collection and ruled out life-threatening conditions such as hemothorax and pneumothorax and prevented abdominal compartment syndrome. Our case is only an example that potentially lethal conditions like these may be encountered in the perioperative setting and the knowledge of eFAST scan may be of great help.

Abdominal compartment syndrome during hip arthroscopy for an acetabular fracture: a case report.

BACKGROUND: We encountered a case of abdominal compartment syndrome during hip arthroscopic surgery, caused by the irrigation fluid flowing into the peritoneal cavity. CASE PRESENTATION: A 47-year-old male patient with the acetabulum fracture underwent open reduction and internal fixation with hip arthroscopy. Hypothermia, increased airway pressure (under volume-controlled ventilation) and oliguria were observed during the operation, and arterial blood gas analysis showed decreased oxygenation and metabolic acidosis. Abdominal distention was observed, and a postoperative CT revealed accumulation of a large volume of irrigation fluid in the peritoneal cavity and retroperitoneum. The patient was diagnosed as having abdominal compartment syndrome and treated by percutaneous peritoneal drainage. His subsequent course was uneventful, and he was discharged 8 weeks after the operation. Intraperitoneal extravasation of irrigation fluid may occur during hip arthroscopic surgery, and is more likely to occur in the presence of an injury. CONCLUSION: Anesthesiologists should be aware of the possible occurrence of the abdominal compartment syndrome during hip arthroscopic surgery and ensure that it is detected early.

Postoperative pectoral swelling after shoulder arthroscopy.

Fluid extravasation is possibly the most common complication of shoulder arthroscopy. Shoulder arthroscopy can lead to major increases in the compartment pressure of adjacent muscles and this phenomenon is significant when an infusion pump is used. This article describes a case of pectoral swelling due to fluid extravasation after shoulder arthroscopy. A 24-year-old male underwent an arthroscopic Bankart repair for recurrent shoulder dislocation. The surgery was performed in the beach chair position and lasted two hours. At the end of the procedure, the patient was found to have left pectoral swelling. A chest radiography showed no abnormality. Pectoral swelling due to fluid extravasation after shoulder arthroscopy has not previously been documented.

Microvascular fluid exchange during pulsatile cardiopulmonary bypass perfusion with the combined use of a nonpulsatile pump and intra-aortic balloon pump.

OBJECTIVE: To evaluate how pulsed versus nonpulsed cardiopulmonary bypass influences microvascular fluid exchange in an experimental setup combining a nonpulsatile perfusion pump and an intra-aortic balloon pump. METHODS: A total of 16 pigs were randomized to pulsatile cardiopulmonary bypass perfusion with an intra-aortic balloon pump switched to an automatic 80 beats/min mode after the start of cardiopulmonary bypass (pulsatile perfusion [PP] group, n = 8) or to nonpulsatile cardiopulmonary bypass with the pump switched to the off position (nonpulsatile [NP] group, n = 8). Normothermic cardiopulmonary bypass was initiated after 60 minutes of stabilization and continued for 3 hours. The fluid needs, plasma volume, colloid osmotic pressure in plasma, colloid osmotic pressure in interstitial fluid, hematocrit, and total tissue water content were recorded, and the protein masses and fluid extravasation rates were calculated. RESULTS: After cardiopulmonary bypass was started, the mean arterial pressure increased in the PP group and decreased in the NP group. At 180 minutes, the mean arterial pressure of the PP and NP groups was 70.9 ± 2.7 mm Hg and 55.9 ± 2.7 mm Hg, respectively (P = .004). The central venous pressure (right atrium) had decreased in the NP group (P = .002). A decreasing trend was seen in the PP group. No between-group differences were present. The hematocrit and colloid osmotic pressure in plasma and interstitial fluid had decreased similarly in both study groups during cardiopulmonary bypass. The plasma volume of the PP group had decreased initially but then returned gradually to precardiopulmonary bypass levels. In the NP group, the plasma volume remained contracted (P = .02). No significant differences in the fluid extravasation rate were obtained. The fluid extravasation rate of the PP group tended to stay slightly higher than the fluid extravasation rate of the NP group at all measurement intervals. The total tissue water content increased significantly in a number of organs compared with that in the control animals. However, differences in the total tissue water content between pulsed and nonpulsed perfusion were absent. CONCLUSIONS: No significant differences in the fluid extravasation rates were present between pulsed and nonpulsed cardiopulmonary bypass perfusion in the present experimental setup.

Negative-pressure pulmonary oedema in a patient undergoing shoulder arthroscopy.

An 18-year-old ASA-I patient who underwent elective left shoulder arthroscopy developed severe airway obstruction post-extubation due to fluid extravasation from the shoulder joint into the neck and airway tissue. Re-intubation for relief of obstruction resulted in negative-pressure pulmonary oedema. The patient was electively ventilated in the intensive care unit and recovered uneventfully. A high index of suspicion along with monitoring of neck circumference can prevent this kind of complication.