Adam Laszlo Balogh

Survivors of severe COVID-19 requiring V-V ECMO exhibit phase-specific abnormalities in respiratory mechanics beyond those detected by conventional whole breath measures. Intrabreath oscillometry revealed elevated end-expiratory resistance and attenuated within-breath resistance modulation, indicating altered phase-dependent resistive mechanics. These findings highlight the complementary value of phase-resolved impedance analysis for characterizing subtle post-COVID respiratory mechanical dysfunction.

Background/Objectives: The Ross procedure is recognized for its excellent long-term outcomes in aortic valve surgery, providing superior hemodynamic performance, freedom from anticoagulation, and a low risk of valve thrombosis. The aim of this study was to evaluate the technical feasibility and early clinical outcomes of performing the Ross procedure through a minimally invasive V-shaped (arrow-shaped) partial sternotomy in adult patients. Methods: Eleven consecutive adult patients underwent a Ross procedure through a 7 cm upper midline skin incision and a V-shaped (arrow-shaped) ministernotomy sternotomy extending to the third intercostal space. Cardiopulmonary bypass was established through central cannulation. The pulmonary autograft was implanted in the aortic position using the miniroot technique, followed by implantation of a pulmonary homograft in the pulmonary position. Operative, perioperative, and early echocardiographic outcomes were prospectively evaluated. Results: All procedures were completed successfully without conversion to full sternotomy or major intraoperative complications. The cardiopulmonary bypass and aortic cross-clamp times were consistent across the series, averaging 144 and 86 min, respectively. Intraoperative transesophageal echocardiography confirmed satisfactory function of both the autograft and homograft in all patients. Postoperative recovery was uneventful, with mechanical ventilation times ranging from 4 to 8 h and intensive care unit stays of 24–48 h. No cases of stroke, renal failure, permanent pacemaker implantation, atrial fibrillation, wound infection, sternal instability, reoperation for bleeding, readmission, or mortality occurred. Patients were discharged between postoperative days 7 and 10. At 3-month follow-up, transthoracic echocardiography demonstrated preserved left ventricular function, absence of aortic regurgitation, and low transvalvular gradients in all patients. Conclusions: This initial single-center case series demonstrates the technical feasibility of performing the Ross procedure through a V-shaped (arrow-shaped) partial sternotomy in carefully selected adult patients. The approach provides satisfactory operative exposure for all components of the procedure while maintaining the advantages of minimally invasive surgery. Larger studies with longer follow-up are required to further evaluate clinical outcomes and long-term durability.

The Ross procedure is highly regarded for its superior long-term outcomes in aortic valve surgery, offering excellent hemodynamic performance and a low risk of valve thrombosis. We present the first 11 cases who underwent arrow-shaped ministernotomy Ross procedure. The surgery began with a 7 cm skin incision, followed by a V”, or arrow-shaped sternotomy to the third intercostal space. The transversal sternal division was made to the superior margin of the fourth rib, in both directions, obtaining an arrowhead shape. Cardiopulmonary bypass was established via central cannulation. The pulmonary autograft was implanted in the aortic position using the miniroot technique, which was followed by the implantation of a pulmonary homograft in the pulmonary position. The cardiopulmonary bypass and aortic crossclamp times were reproducible, with an average of 144 and 86 minutes, respectively. The surgery was completed without complications, and intraoperative transesophageal echocardiography confirmed the successful functioning of the valves. The patients’ postoperative course was straightforward, characterized by a short stay in the intensive care unit and discharge on postoperative day 7-10. Thes cases demonstrate, that the minimally invasive Ross procedure is a safe and effective option in centers with expertise in both minimal access cardiac surgery and the Ross procedure itself. The ministernotomy approach, which provides excellent exposure and reduced surgical trauma, may be particularly beneficial for young, active patients. Given the positive outcomes observed, the approach could be considered a viable alternative to traditional full sternotomy in similar surgical cases.

Crystalloids are first line in fluid resuscitation therapy, however there is a lack of evidence-based recommendations on the volume to be administered. Therefore, we aimed at comparing the systemic hemodynamic and respiratory effects of volume replacement therapy with a 1:1 ratio to the historical 1:3 ratio. Anesthetized, ventilated rats randomly included in 3 groups: blood withdrawal and replacement with crystalloid in 1:1 ratio (Group 1, n = 11), traditional 1:3 ratio (Group 3, n = 12) and a control group with no interventions (Group C, n = 9). Arterial blood of 5% of the total blood volume was withdrawn 7 times, and replaced stepwise with different volume rations of Ringer’s acetate, according to group assignments. Airway resistance (Raw), respiratory tissue damping (G) and tissue elastance (H), mean arterial pressure (MAP) and heart rate (HR) were assessed following each step of fluid replacement with a crystalloid (CR1-CR6). Lung edema index was measured from histological samples. Raw decreased in Groups 1 and 3 following CR3 (p < 0.02) without differences between the groups. H elevated in all groups (p < 0.02), with significantly higher changes in Group 3 compared to Groups C and 1 (both p = 0.03). No differences in MAP or HR were present between Groups 1 and 3. Lung edema was noted in Group 3 (p < 0.05). Fluid resuscitation therapy by administering a 1:1 blood replacement ratio revealed adequate compensation capacity and physiological homeostasis similar with no lung stiffening and pulmonary edema. Therefore, considering this ratio promotes the restrictive fluid administration in the presence of continuous and occult bleeding.

Levosimendan has a calcium-sensitizing effect in the myocardium and opens ATP-sensitive potassium channels (K_ATP) in vascular smooth muscle. Because airway smooth muscle also expresses K_ATP, we characterized the protective potential of levosimendan against increased airway and respiratory tissue resistances. Animals were administered levosimendan alone ( group L), levosimendan after pretreatment with a K_ATPchannel blocker (glibenclamide, group LG), glibenclamide only ( group G), or solvent alone (dextrose, group C). Airway resistance (R_aw), tissue damping, and elastance were determined by forced oscillations under baseline conditions and following provocation tests with intravenous methacholine (MCh). Cardiac output (CO) was assessed by transpulmonary thermodilution. The same sequence of measurements was then repeated during intravenous infusion of levosimendan in groups L and LG or glucose in groups G and C. Sham treatments in groups C and G had no effect on lung responsiveness. However, levosimendan treatment in group L elevated CO and inhibited the MCh-induced airway responses [R_awchanges of 87.8 ± 83% (SD) vs. 24.4 ± 16% at 4 μg·kg⁻¹·min⁻¹MCh, P < 0.001], and in G (35.2 ± 12.7 vs. 25.2 ± 12.9%, P < 0.05). The preventive affect of levosimendan against lung constriction vanished in the LG group. Levosimendan exerts a K_ATP-mediated potential to prevent bronchoconstriction and may prohibit adverse lung peripheral changes both in the small bronchi and the pulmonary parenchyma. The identification of a further pleiotropic property of levosimendan that is related to the pulmonary system is of particular importance for patients with decreased cardiorespiratory reserves for which simultaneous circulatory support is complemented with prevention of adverse respiratory events.