A Special, Modified, Double-Lumen Tube for One-Lung Ventilation in Pigs

Animal studies in pigs often depend in thoracic anaesthesia on effective lung separation. In this report we describe the use of a modified double-lumen endotracheal tube for one-lung or differential lung ventilation in pigs resulting in excellent lung separation and unimpaired hypoxic pulmonary vasoconstriction

Incidence and Sequelae of Prosthesis-Patient Mismatch in Transcatheter Versus Surgical Valve Replacement in High-Risk Patients With Severe Aortic Stenosis A PARTNER Trial Cohort-A Analysis

AbstractBackgroundLittle is known about the incidence of prosthesis-patient mismatch (PPM) and its impact on outcomes after transcatheter aortic valve replacement (TAVR).ObjectivesThe objectives of this study were: 1) to compare the incidence of PPM in the TAVR and surgical aortic valve replacement (SAVR) randomized control trial (RCT) arms of the PARTNER (Placement of AoRTic TraNscathetER Valves) I Trial cohort A; and 2) to assess the impact of PPM on regression of left ventricular (LV) hypertrophy and mortality in these 2 arms and in the TAVR nonrandomized continued access (NRCA) registry cohort.MethodsThe PARTNER Trial cohort A randomized patients 1:1 to TAVR or bioprosthetic SAVR. Postoperative PPM was defined as absent if the indexed effective orifice area (EOA) was >0.85 cm2/m2, moderate if the indexed EOA was ≥0.65 but ≤0.85 cm2/m2, or severe if the indexed EOA was <0.65 cm2/m2. LV mass regression and mortality were analyzed using the SAVR-RCT (n = 270), TAVR-RCT (n = 304), and TAVR-NRCA (n = 1,637) cohorts.ResultsThe incidence of PPM was 60.0% (severe: 28.1%) in the SAVR-RCT cohort versus 46.4% (severe: 19.7%) in the TAVR-RCT cohort (p < 0.001) and 43.8% (severe: 13.6%) in the TAVR-NRCA cohort. In patients with an aortic annulus diameter <20 mm, severe PPM developed in 33.7% undergoing SAVR compared with 19.0% undergoing TAVR (p = 0.002). PPM was an independent predictor of less LV mass regression at 1 year in the SAVR-RCT (p = 0.017) and TAVR-NRCA (p = 0.012) cohorts but not in the TAVR-RCT cohort (p = 0.35). Severe PPM was an independent predictor of 2-year mortality in the SAVR-RCT cohort (hazard ratio [HR]: 1.78; p = 0.041) but not in the TAVR-RCT cohort (HR: 0.58; p = 0.11). In the TAVR-NRCA cohort, severe PPM was not a predictor of 1-year mortality in all patients (HR: 1.05; p = 0.60) but did independently predict mortality in the subset of patients with no post-procedural aortic regurgitation (HR: 1.88; p = 0.02).ConclusionsIn patients with severe aortic stenosis and high surgical risk, PPM is more frequent and more often severe after SAVR than TAVR. Patients with PPM after SAVR have worse survival and less LV mass regression than those without PPM. Severe PPM also has a significant impact on survival after TAVR in the subset of patients with no post-procedural aortic regurgitation. TAVR may be preferable to SAVR in patients with a small aortic annulus who are susceptible to PPM to avoid its adverse impact on LV mass regression and survival. (The PARTNER Trial: Placement of AoRTic TraNscathetER Valve Trial; NCT00530894

Characterization of the seven-day course of pulmonary response following unilateral lung acid injury in rats

<div><p>Background</p><p>Aspiration of gastric acid is an important cause of acute lung injury. The time course of the pulmonary response to such an insult beyond the initial 48 hours is incompletely characterized. The purpose of this study was to comprehensively describe the pulmonary effects of focal lung acid injury over a seven day period in both directly injured and not directly injured lung tissue.</p><p>Methods</p><p>Male Wistar rats underwent left-endobronchial instillation with hydrochloric acid and were sacrificed at 4, 24, 48, 96 or 168 h after the insult. Healthy non-injured animals served as controls. We assessed inflammatory cell counts and cytokine levels in right and left lung lavage fluid and blood, arterial oxygen tension, alterations in lung histology, lung wet-to-dry weight ratio and differential lung perfusion.</p><p>Results</p><p>Lung acid instillation induced an early strong inflammatory response in the directly affected lung, peaking at 4–24 hours, with only partial resolution after 7 days. A less severe response with complete resolution after 4 days was seen in the opposite lung. Alveolar cytokine levels, with exception of IL-6, only partially reflected the localization of lung injury and the time course of the functional and histologic alterations. Alveolar leucocyte subpopulations exhibited different time courses in the acid injured lung with persistent elevation of alveolar lymphocytes and macrophages. After acid instillation there was an early transient decrease in arterial oxygen tension and lung perfusion was preferentially distributed to the non-injured lung.</p><p>Conclusion</p><p>These findings provide a basis for further research in the field of lung acid injury and for studies exploring effects of mechanical ventilation on injured lungs. Incomplete recovery in the directly injured lung 7 days after acid instillation suggests that increased vulnerability and susceptibility to further noxious stimuli are still present at that time.</p></div

Lung wet-to-dry weight ratio and alveolar protein concentration after left lung acid instillation.

<p>* = p < 0.05 vs. no acid instillation. ** = p < 0.001 vs. no acid instillation. # = p < 0.05 vs. right lung.</p

Blood leukocyte counts (cells/ μl) prior (= baseline) and after left lung hydrochloric acid injury.

<p>Blood leukocyte counts (cells/ μl) prior (= baseline) and after left lung hydrochloric acid injury.</p

Representative hematoxylin & eosin stained tissue sections from left lungs before and in the early phase after left lung acid instillation.

<p>At 4 h after acid instillation focal areas of alveolar inflammation (lower part of tissue section, arrows) were seen adjacent to mostly normal lung tissue (upper part of tissue section). At 24 h after acid instillation a diffuse alveolar and interstitial inflammatory infiltrate, consisting predominantly of neutrophils was the characteristic finding in all animals. Original magnification is x200.</p

Concentrations of interleukin 6 (IL-6), macrophage inhibitory protein 2 (MIP-2) and interleukin 10 (IL-10) in left and right lung lavage fluid following left lung acid instillation.

<p>Please note different scales on the y-axes. * = p < 0.05 vs. no acid instillation. # = p < 0.05 vs. right lung.</p

Neutrophil, macrophage and lymphocyte counts in left and right lung lavage fluid following left lung acid instillation.

<p>Please note that scales on the y-axes are different. * = p < 0.05 vs. no acid instillation. # = p < 0.05 vs. right lung.</p