Placement of subcutaneous ureteral bypasses without fluoroscopic guidance in cats with ureteral obstruction: 19 cases (2014-2016).

Objectives The purpose of this study was to describe the perioperative and postoperative complications as well as short-term and long-term outcomes in cats with ureteral obstructions treated by placement of a subcutaneous ureteral bypass (SUB) device without imaging control. The second objective of this study was to compare cats treated by SUB device with cats treated by traditional surgical intervention. Methods Data were obtained retrospectively from the medical records (2014-2016) of cats that underwent SUB placement (SUB cats) and cats that underwent traditional ureteral surgery (C cats). Results Nineteen SUB devices were placed without fluoroscopic, radiographic or ultrasonographic guidance in 13 cats. Fifteen traditional interventions (ureterotomy and neoureterocystostomy) were performed in 11 cats. Successful placement of the SUB device was achieved in all cats with only one major intraoperative complication (kinking of the kidney catheter) and one minor intraoperative complication (misplacement of the kidney catheter). Eleven SUB cats recovered from the surgical procedure; two SUB cats and three C cats died during the anaesthesia recovery period. Postoperative SUB complications included anaemia (n = 2), urinary tract infection (UTI) (n = 4), non-infectious cystitis (n = 5) and SUB device obstruction (n = 1). Postoperative traditional surgery complications included anaemia (n = 7), UTIs (n = 6), non-infectious cystitis (n = 1), re-obstruction (n = 4) and ureteral stricture (n = 1). Median postoperative duration of hospitalisation (3 days) was significantly shorter for SUB cats than for C cats ( P = 0.013). Ten SUB cats (76.9%) and four C cats (40%) were still alive at a median follow-up of 225 days and 260 days, respectively. Owners were completely (90%) or mostly (10%) satisfied with the SUB device placement. Conclusions and relevance SUB device placement appears to be an effective and safe option for treating ureteral obstruction in cats, and this study has shown that fluoroscopic guidance is not essential in all cases.

Reliability of the nitrogen washin-washout technique to assess end-expiratory lung volume at variable PEEP and tidal volumes.

BACKGROUND: End-expiratory lung volume measurement by the nitrogen washin-washout technique (EELVWI-WO) may help titrating positive end-expiratory pressure (PEEP) during acute respiratory distress syndrome (ARDS). Validation of this technique has been previously performed using computed tomography (EELVCT), but at mild PEEP levels, and relatively low fraction of inspired oxygen (FiO2), which may have insufficiently challenged the validity of this technique. The aims of this study were (1) to evaluate the reliability of EELVWI-WO measurements at different PEEP and V T during experimental ARDS and (2) to evaluate trending ability of EELVWI-WO to detect EELV changes over time. METHODS: ARDS was induced in 14 piglets by saline lavage. Optimal PEEP was selected during a decremental PEEP trial, based on best compliance, best EELVWI-WO, or a PEEP-FiO2 table. Eight V T (4 to 20 mL · kg(-1)) were finally applied at optimal PEEP. EELVWI-WO and EELVCT were determined after ARDS onset, at variable PEEP and V T. RESULTS: EELVWI-WO underestimated EELVCT with a non-constant linear bias, as it decreased with increasing EELV. Limits of agreement for bias were ±398 mL. Bias between methods was greater at high PEEP, and further increased when high PEEP was combined with low V T. Concordance rate of EELV changes between consecutive measurements was fair (79%). Diagnostic accuracy was good for detection of absolute EELV changes above 200 mL (AUC = 0.79). CONCLUSIONS: The reliability of the WI-WO technique is critically dependent on ventilatory settings, but sufficient to accurately detect EELV change greater than 200 mL.

Noninvasive quantitative assessment of pulmonary blood flow with 18F-FDG PET.

UNLABELLED: Pulmonary blood flow (PBF) is a critical determinant of oxygenation during acute lung injury (ALI). PET/CT with (18)F-FDG allows the assessment of both lung aeration and neutrophil inflammation as well as an estimation of the regional fraction of blood (FB) if compartmental modeling is used to quantify (18)F-FDG pulmonary uptake. The aim of this study was to validate the use of FB to assess PBF, with PET and compartmental modeling of (15)O-H2O kinetics as a reference method, in both control animals and animals with ALI. For the purpose of studying a wide range of PBF values, supine and prone positions and various positive end-expiratory pressures (PEEPs) and tidal volumes (V(T)s) were selected. METHODS: Pigs were randomized into 3 groups in which ALI was induced by HCl inhalation: pigs studied in the supine position with a low PEEP (5 ± 3 [mean ± SD] cm of H2O; n = 9) or a high PEEP (12 ± 1 cm of H2O; n = 8) and pigs studied in the prone position with a low PEEP (6 ± 3 cm of H2O; n = 9). Also included were a control group that did not have ALI (n = 6) and 2 additional groups (n = 6 each) that had a high V(T) to maintain a transpulmonary pressure of greater than or equal to 35 cm of H2O and that either received HCl inhalation or did not receive HCl inhalation. PBF and FB were measured with PET and compartmental modeling of (15)O-H2O and (18)F-FDG kinetics in 10 lung regions along the anterior-to-posterior lung dimension, and both were expressed in each region as a fraction of their values in the whole lung. RESULTS: PBF and FB were strongly correlated (R(2) = 0.9), with a slope of the regression line close to unity and a negligible intercept. The mean difference between PBF and FB was 0, and the 95% limits of agreement were -0.035 to 0.035. This good agreement between methods was obtained in both normal and injured lungs and under a wide range of V(T), PEEP, and regional PBF values (7-71 mL/kg, 0-15 cm of H2O, and 24-603 mL·min(-1)·100 mL of lung(-1), respectively). CONCLUSION: FB assessed with (18)F-FDG is a good surrogate for PBF in both normal animals and animals with ALI. PET/CT has the potential to be used to study ventilation, perfusion, and lung inflammation with a single tracer.