Pulmonary Shunt Research Articles

Impact of Positive End-Expiratory Pressure and FiO2 on Lung Mechanics and Intrapulmonary Shunt in Mechanically Ventilated Patients with ARDS Due to COVID-19 Pneumonia.

Purpose: This study aimed to investigate the effects of inspired oxygen fraction (FiO2) and positive end-expiratory pressure (PEEP) on gas exchange in mechanically ventilated patients with COVID-19. Methods: Two FiO2 (100%, 40%) were tested at 3 decreasing levels of PEEP (15, 10, and 5 cmH2O). At each FiO2 and PEEP, gas exchange, respiratory mechanics, hemodynamics, and the distribution of ventilation and perfusion were assessed with electrical impedance tomography. The impact of FiO2 on the intrapulmonary shunt (delta shunt) was analyzed as the difference between the calculated shunt at FiO2 100% (shunt) and venous admixture at FiO2 40% (venous admixture). Results: Fourteen patients were studied. Decreasing PEEP from 15 to 10 cmH2O did not change shunt (24 [21-28] vs 27 [24-29]%) or venous admixture (18 [15-26] vs 23 [18-34]%) while partial pressure of arterial oxygen (FiO2 100%) was higher at PEEP 15 (262 [198-338] vs 256 [147-315] mmHg; P < .05). Instead when PEEP was decreased from 10 to 5 cmH2O, shunt increased to 36 [30-39]% (P < .05) and venous admixture increased to 33 [30-43]% (P < .05) and partial pressure of arterial oxygen (100%) decreased to 109 [76-177] mmHg (P < .05). At PEEP 15, administration of 100% FiO2 resulted in a shunt greater than venous admixture at 40% FiO2, ((24 [21-28] vs 18 [15-26]%, P = .005), delta shunt 5.5% (2.3-8.8)). Compared to PEEP 10, PEEP of 5 and 15 cmH2O resulted in decreased global and pixel-level compliance. Cardiac output at FiO2 100% resulted higher at PEEP 5 (5.4 [4.4-6.5]) compared to PEEP 10 (4.8 [4.1-5.5], P < .05) and PEEP 15 cmH2O (4.7 [4.5-5.4], P < .05). Conclusion: In this study, PEEP of 15 cmH2O, despite resulting in the highest oxygenation, was associated with overdistension. PEEP of 5 cmH2O was associated with increased shunt and alveolar collapse. Administration of 100% FiO2 was associated with an increase in intrapulmonary shunt in the setting of high PEEP. Trial registration: NCT05132933.

Comparison of treprostinil and oral sildenafil for the treatment of persistent pulmonary hypertension of the newborn: a retrospective cohort study.

This study aims to evaluate the effectiveness of treprostinil and oral sildenafil in managing persistent pulmonary hypertension of newborns (PPHN). We conducted a retrospective cohort study of 42 neonates with PPHN treated with continuous intravenous treprostinil or oral sildenafil from January 2020 to October 2022 in China. Outcomes assessed included echocardiographic pulmonary artery systolic pressure (PASP), shunt direction, and arterial blood gas measures. Treprostinil lowered PASP and improved oxygenation significantly better than sildenafil on days 1, 2, and 3 of treatment (P < 0.05). Treprostinil also corrected shunt direction faster than sildenafil (P < 0.05). The duration of mechanical ventilation, length of NICU stay, and overall hospital stay did not significantly differ between the two groups (P > 0.05). Treprostinil effectively lowers pulmonary artery pressure and improves oxygenation in neonates with PPHN, without being associated with severe complications. It may serve as a beneficial adjunct therapy for neonates with PPHN.

Influencing factors of lung shunt fraction in transarterial radioembolization treatment

Influencing factors of lung shunt fraction in transarterial radioembolization treatment

Change in Right-to-Left Shunt Fraction in Patients with Chronic Thromboembolic Pulmonary Hypertension after Pulmonary Endarterectomy.

Pulmonary endarterectomy (PEA) is the treatment of choice for patients with chronic thromboembolic pulmonary hypertension (CTEPH) with accessible lesions. Breathing pure oxygen (hyperoxia) during right heart catheterization (RHC) allows for the calculation of the right-to-left shunt fraction (Qs/Qt). In the absence of intracardiac shunt, Qs/Qt can be used as a marker of ventilation-perfusion mismatch in patients with CTEPH. This study involved investigating Qs/Qt after PEA and its relation to other disease-specific outcomes. This study is a retrospective study that focuses on patients with operable CTEPH who had Qs/Qt assessment during RHC before and 1 year after PEA. Additionally, 6 min walking distance (6MWD), WHO functional class (WHO-FC), and NT-proBNP were assessed to calculate a four-strata risk score. Overall, 16 patients (6 females) with a median age of 66 years (quartiles 55; 74) were included. After PEA, an improvement in mean pulmonary artery pressure (38 [32; 41] to 24 [18; 28] mmHg), pulmonary vascular resistance (5.7 [4.0; 6.8] to 2.5 [1.4; 3.8] WU), oxygen saturation (92 [88; 93]% to 94 [93; 95]%), WHO-FC, and risk score was observed (all p < 0.05). No improvement in median Qs/Qt could be detected (13.7 [10.0; 17.5]% to 13.0 [11.2; 15.6]%, p = 0.679). A total of 7 patients with improved Qs/Qt had a significant reduction in risk score compared to those without improved Qs/Qt. PEA did not alter Qs/Qt assessed after 1 year in operable CTEPH despite an improvement in hemodynamics and risk score, potentially indicating a persistent microvasculopathy. In patients whose shunt fraction improved with PEA, the reduced shunt was associated with an improvement in risk score.

Application of anti-inflammatory treatment in two different ovine Acute Respiratory Distress Syndrome injury models: a preclinical randomized intervention study

Whilst the presence of 2 subphenotypes among the heterogenous Acute Respiratory Distress Syndrome (ARDS) population is becoming clinically accepted, subphenotype-specific treatment efficacy has yet to be prospectively tested. We investigated anti-inflammatory treatment in different ARDS models in sheep, previously shown similarities to human ARDS subphenotypes, in a preclinical, randomized, blinded study. Thirty anesthetized sheep were studied up to 48 h and randomized into: (a) OA: oleic acid (n = 15) and (b) OA-LPS: oleic acid and subsequent lipopolysaccharide (n = 15) to achieve a PaO2/FiO2 ratio of < 150 mmHg. Then, animals were randomly allocated to receive treatment with methylprednisolone or erythromycin or none. Assessed outcomes were oxygenation, pulmonary mechanics, hemodynamics and survival. All animals reached ARDS. Treatment with methylprednisolone, but not erythromycin, provided the highest therapeutic benefit in Ph2 animals, leading to a significant increase in PaO2/FiO2 ratio by reducing pulmonary edema, dead space ventilation and shunt fraction. Animals treated with methylprednisolone displayed a higher survival up to 48 h than all others. In animals treated with erythromycin, there was no treatment benefit regarding assessed physiological parameters and survival in both phenotypes. Treatment with methylprednisolone improves oxygenation and survival, more so in ovine phenotype 2 which resembles the human hyperinflammatory subphenotype.

AAPM Medical Physics Practice Guideline 14.a: Yttrium-90 microsphere radioembolization.

Radioembolization using Yttrium-90 (90 Y) microspheres is widely used to treat primary and metastatic liver tumors. The present work provides minimum practice guidelines for establishing and supporting such a program. Medical physicists play a key role in patient and staff safety during these procedures. Products currently available are identified and their properties and suppliers summarized. Appropriateness for use is the domain of the treating physician. Patient work up starts with pre-treatment imaging. First, a mapping study using Technetium-99m (Tc-99m ) is carried out to quantify the lung shunt fraction (LSF) and to characterize the vascular supply of the liver. An MRI, CT, or a PET-CT scan is used to obtain information on the tumor burden. The tumor volume, LSF, tumor histology, and other pertinent patient characteristics are used to decide the type and quantity of 90 Y to be ordered. On the day of treatment, the appropriate dose is assayed using a dose calibrator with a calibration traceable to a national standard. In the treatment suite, the care team led by an interventional radiologist delivers the dose using real-time image guidance. The treatment suite is posted as a radioactive area during the procedure and staff wear radiation dosimeters. The treatment room, patient, and staff are surveyed post-procedure. The dose delivered to the patient is determined from the ratio of pre-treatment and residual waste exposure rate measurements. Establishing such a treatment modality is a major undertaking requiring an institutional radioactive materials license amendment complying with appropriate federal and state radiation regulations and appropriate staff training commensurate with their respective role and function in the planning and delivery of the procedure. Training, documentation, and areas for potential failure modes are identified and guidance is provided to ameliorate them.

Increased intrapulmonary shunt and alveolar dead space post-COVID-19.

Increased intrapulmonary shunt (QS/Qt) and alveolar dead space (VD/VT) are present in early recovery from 2019 Novel Coronavirus (COVID-19). We hypothesized patients recovering from severe critical acute illness (NIH category 3-5) would have greater and longer lasting increased QS/Qt and VD/VT than patients with mild-moderate acute illness (NIH 1-2). Fifty-nine unvaccinated patients (33 males, aged 52 [38-61] yr, body mass index [BMI] 28.8 [25.3-33.6] kg/m2; median [IQR], 44 previous mild-moderate COVID-19, and 15 severe-critical disease) were studied 15-403 days postacute severe acute respiratory syndrome coronavirus infection. Breathing ambient air, steady-state mean alveolar Pco2, and Po2 were recorded simultaneously with arterial Po2/Pco2 yielding aAPco2, AaPo2, and from these, QS/Qt%, VD/VT%, and relative alveolar ventilation (40 mmHg/[Formula: see text], VArel) were calculated. Median [Formula: see text] was 39.4 [35.6-41.1] mmHg, [Formula: see text] 92.3 [87.1-98.2] mmHg; [Formula: see text] 32.8 [28.6-35.3] mmHg, [Formula: see text] 112.9 [109.4-117.0] mmHg, AaPo2 18.8 [12.6-26.8] mmHg, aAPco2 5.9 [4.3-8.0] mmHg, QS/Qt 4.3 [2.1-5.9] %, and VD/VT16.6 [12.6-24.4]%. Only 14% of patients had normal QS/Qt and VD/VT; 1% increased QS/Qt but normal VD/VT; 49% normal QS/Qt and elevated VD/VT; 36% both abnormal QS/Qt and VD/VT. Previous severe critical COVID-19 predicted increased QS/Qt (2.69 [0.82-4.57]% per category severity [95% CI], P < 0.01), but not VD/VT. Increasing age weakly predicted increased VD/VT (1.6 [0.1-3.2]% per decade, P < 0.04). Time since infection, BMI, and comorbidities were not predictors (all P > 0.11). VArel was increased in most patients. In our population, recovery from COVID-19 was associated with increased QS/Qt in 37% of patients, increased VD/VT in 86%, and increased alveolar ventilation up to ∼13 mo postinfection. NIH severity predicted QS/Qt but not elevated VD/VT. Increased VD/VT suggests pulmonary microvascular pathology persists post-COVID-19 in most patients.NEW & NOTEWORTHY Using novel methodology quantifying intrapulmonary shunt and alveolar dead space in COVID-19 patients up to 403 days after acute illness, 37% had increased intrapulmonary shunt and 86% had elevated alveolar dead space likely due to independent pathology. Elevated shunt was partially related to severe acute illness, and increased alveolar dead space was weakly related to increasing age. Ventilation was increased in the majority of patients regardless of previous disease severity. These results demonstrate persisting gas exchange abnormalities after recovery.

Intrapulmonary distribution of blood flow during exercise in pulmonary hypertension assessed by a new combination technique.

Hyperventilation and inadequate cardiac output (CO) increase are the main causes of exercise limitation in pulmonary hypertension (PH). Intrapulmonary blood flow partitioning between ventilated and unventilated lung zones is unknown. Thoracic impedance cardiography and inert gas rebreathing have been both validated in PH patients for non-invasive measurement of CO and pulmonary blood flow (PBF), respectively. This study sought to evaluate CO behaviour in PH patients during exercise and its partitioning between ventilated and unventilated lung areas, in parallel with ventilation partitioning between ventilated and unventilated lung zones. Eighteen PH patients (group 1 or 4) underwent a cardiopulmonary exercise test (CPET) with a three-step loaded workload protocol. The steps occurred at 0%, 20%, 40%, and 60% of peak workload reached during a preliminary maximum CPET. Ventilatory parameters, arterial blood gases, CO, PBF, and intrapulmonary shunt (calculated as the difference between CO and PBF) were obtained at each step, combining thoracic impedance cardiography and an inert gas rebreathing technique. Dead space ventilation observed throughout the exercise was about 40% of total ventilation. A progressive increase of CO from 4.86 ± 1.24 L/min (rest) to 9.41 ± 2.63 L/min (last step), PBF from 3.81 ± 1.41 L/min to 7.21 ± 2.93 L/min, and intrapulmonary shunt from 1.05 ± 0.96 L/min to 2.21 ± 2.28 L/min was observed. Intrapulmonary shunt was approximately 20% of CO at each exercise step. Although the study population was small, the combined non-invasive CO measurement seems a promising tool for deepening our knowledge of lung exercise haemodynamics in PH patients. This technique could be applied in future studies to evaluate PH treatment influences on CO partitioning, since a secondary increase of intrapulmonary shunt is undesirable.

A pediatric case of portosystemic shunt presenting hypoxemia with brain abscess in an emergency department

Portosystemic shunt is a rare congenital vascular anomaly. The shunt is hard to clinically suspect because its symptoms develop insidiously and affect various systems at different time points. We report a case of an 11-year-old girl who presented with brain abscess and hypoxemia without respiratory distress. No abnormality related to the hypoxemia, such as intracardiac shunt, was found on the initial chest radiograph and echocardiogram. However, computed tomography showed a portosystemic shunt. An intrapulmonary shunt was demonstrated by bubble contrast echocardiography, indicating a grade 2 hepatopulmonary syndrome, a complication of portosystemic shunt. This case describes the diagnostic process of an unusual case presenting neurological abnormalities and hypoxemia without respiratory distress. Portosystemic shunt with hepatopulmonary syndrome should be considered in the differential diagnosis of unexplained hypoxemia.

A Stroke and a Strange Intrapulmonary Shunt

A Stroke and a Strange Intrapulmonary Shunt

Management of systemic to pulmonary shunts and elevated pulmonary vascular resistance.

Repair of systemic to pulmonary shunts is timed to prevent the development of irreversible pulmonary vascular disease, including in patients with other factors contributing to pulmonary hypertension. This study assessed outcomes of an individualised strategy for managing patients with mild-moderately elevated pulmonary vascular resistance (PVR) deemed borderline eligible for repair. A retrospective chart review was conducted of patients with systemic to pulmonary shunts and baseline indexed PVR (PVRi) ≥3 WU·m2 treated at a single centre from 1 January 2005 to 30 September 2019. Data included demographics, World Health Organization functional class (WHO FC), medications and haemodynamic data at baseline and serial follow-up. 30 patients (18 females) met criteria for inclusion. Median age at diagnosis of pulmonary arterial hypertension was 1.3 years (range 0.03-54 years) and at surgery was 4.1 years (range 0.73-56 years). Median follow-up time was 5.8 years (range 0.2-14.6 years) after repair. Most patients received at least one targeted pulmonary arterial therapy prior to repair and the majority (80%) underwent fenestrated shunt closure. There was a significant decrease in mean pulmonary arterial pressure (mPAP) (p<0.01), PVRi (p=0.0001) and PVR/systemic vascular resistance (p<0.01) between baseline and preoperative catheterisation and a decrease in PVRi (p<0.005), mPAP (p=0.0001) and pulmonary to systemic flow ratio (p<0.03) from baseline to most recent catheterisation. WHO FC improved from FC II-III at baseline to FC I post repair in most patients (p<0.003). In carefully selected patients with systemic to pulmonary shunts and elevated PVR considered borderline for operability, the use of preoperative targeted therapy in conjunction with fenestrated or partial closure of intracardiac shunts is associated with improvement in WHO FC and clinical outcomes.

The effect of inhaled nitric oxide on shunt fraction in mechanically ventilated patients with COVID-19 pneumonia.

Studies in patients with severe acute respiratory distress syndrome (ARDS) with refractory hypoxaemia suggest that inhaled nitric oxide (iNO) can be added to ventilatory strategies as a potential bridge to clinical improvement. However, the potential role of iNO as a management strategy in severe COVID-19 pneumonia remains unclear. The authors describe their clinical findings of using iNO for severe COVID-19 pneumonia in 10 patients with refractory hypoxaemia in a tertiary respiratory intensive care unit. The results showed an improvement in shunt fraction, P/F ratio, PaO2 and arterial oxygen saturation but the improvements did not translate into a mortality benefit. This report adds to the current body of literature indicating that the correct indications, timing, dose and duration of iNO therapy and how to harness its pleiotropic effects still remain to be elucidated. This brief report adds to the body of literature exploring the potential use of inhaled nitric oxide as a management strategy in patients with severe COVID-19 pneumonia with refractory hypoxaemia. The findings of the report shows that there is a beneficial role of using inhaled nitric oxide to improve respiratory parameters, but that it does not translate to a mortality benefit. It adds to the investigation of establishing which patients, the duration and at what dose, inhaled nitric oxide should be used to gain maximum benefit for this subgroup of patients.

New insights learned from the pulmonary to systemic blood flow ratio to predict the outcome in patients with hypoplastic left heart syndrome in the pre-Glenn stage: a single-center study.

To the best of our knowledge, no study has been made until now to determine whether the ratio between pulmonary and systemic blood flow (Qp/Qs) in the pre-stage II (PS2) or pre-Glenn stage can predict the outcome in patients with hypoplastic left heart syndrome (HLHS) who underwent Norwood (NW) palliation. From January 2016 to August 2022, 80 cardiac catheterizations in 69 patients with HLHS in NW palliation stage with modified Blalock-Taussig shunt (MBTS) were retrospectively recruited. The Qp/Qs was measured under stable conditions using the Fick formula. None of the patients were intubated. Patients were divided into two groups: Group 1 included patients who underwent planned cardiac catheterization (n = 56), and Group 2 had unplanned examination (n = 13), in which the indication for cardiac catheterization was desaturation in 11 patients and pulmonary over-circulation in two. The composite primary outcome was defined as accomplishing the planned operations (Glenn and Fontan) with freedom from death and reoperation, referring to palliative therapy or heart transplantation. The secondary outcome was freedom from transcatheter intervention in MBTS or pulmonary arteries. The median follow-up was 48 months (range 6-72 months). The median value of Qp/Qs in Group 1 was 1.75 (range 1.5-2.2). In Group 2, the 11 patients with desaturation, the median value of Qp/Qs was 1.25 (range 0.9-1.45). The two patients with suspected pulmonary overcalculation showed Qp/Qs of 2.3 and 2.5, respectively; a reduction of the shunt size was required. Approximately 96.4% of patients in Group 1 achieved the primary outcome compared with only 30.7% in Group 2. The need for reintervention was 1.8% in Group 1 compared with 61.3% in Group 2. There is a significant relationship between Qp/Qs and the impaired outcome (death, palliative therapy, or heart transplantation) with a p-value of 0.001, a relative risk factor of 3.1, and a 95% confidence interval of 1.4-7.1. No significant relationship between the Qp/Qs and the size of MBTS (p-value of 0.073) was noted. The Qp/Qs in PS2 can predict outcomes in patients with HLHS in Norwood stage with MBTS. The Qp/Qs between 1.5 and 2.2 with a median of 1.75 seems to be optimal in the patients in PS2. Qp/Qs of <1.5 is associated with pulmonary stenosis, shunt stenosis, and pulmonary hypertension.

An Experimental Cold Gas Cannon for the Study of Porcine Lung Contusion and Behind Armor Blunt Trauma

Behind armor blunt trauma (BABT) is a non-penetrating injury caused by the rapid deformation of body armor, by a projectile, which may in extreme circumstances cause death. The understanding of the mechanisms is still low, in relation to what is needed for safety threshold levels. Few models of graded kinetic energy transfer to the body exist. We established an experimental model for graded BABT. The cold gas cannon was air-driven, consisted of a pressure vessel, a barrel, and a pressure actuator. It required short training to operate and was constructed by standard components. It produced standardized expulsion of plastic projectiles with 65 mm and weight 58 g. Velocity correlated linearly to pressure (R 0.9602, p < 0.0001), equation Y = 6.558*X + 46.50. Maximum tested pressure was 10 bar, velocity 110 m/s and kinetic energy (Ek) 351 J. Crossbred male swine (n = 10) mean weight (SD) 56 ± 3 kg, were subjected to BABT, mean Ek (SD) 318 (61) J, to a fix point on the right lateral thorax. Pulmonary contusion was confirmed by physiological parameters pO2 (p < 0.05), SaO2 (p < 0.01), pCO2 (p < 0.01), etCO2 (p < 0.01), MPAP (p < 0.01), Cstat (p < 0.01), intrapulmonary shunt (Q′s/Q′t) (p < 0.05), and qualified trans-thoracic ultrasound (p < 0.0001). The consistent injury profile enabled for the addition of future experimental interventions.

Prognostic value of right ventricular dilatation on computed tomography pulmonary angiogram for predicting adverse clinical events in severe COVID-19 pneumonia.

Right ventricle dilatation (RVD) is a common complication of non-intubated COVID-19 pneumonia caused by pro-thrombotic pneumonitis, intra-pulmonary shunting, and pulmonary vascular dysfunction. In several pulmonary diseases, RVD is routinely measured on computed tomography pulmonary angiogram (CTPA) by the right ventricle-to-left ventricle (LV) diameter ratio > 1 for predicting adverse events. The aim of the study was to evaluate the association between RVD and the occurrence of adverse events in a cohort of critically ill non-intubated COVID-19 patients. Between February 2020 and February 2022, non-intubated patients admitted to the Amiens University Hospital intensive care unit for COVID-19 pneumonia with CTPA performed within 48 h of admission were included. RVD was defined by an RV/LV diameter ratio greater than one measured on CTPA. The primary outcome was the occurrence of an adverse event (renal replacement therapy, extracorporeal membrane oxygenation, 30-day mortality after ICU admission). Among 181 patients, 62% (n = 112/181) presented RVD. The RV/LV ratio was 1.10 [1.05-1.18] in the RVD group and 0.88 [0.84-0.96] in the non-RVD group (p = 0.001). Adverse clinical events were 30% and identical in the two groups (p = 0.73). In Receiving operative curves (ROC) analysis, the RV/LV ratio measurement failed to identify patients with adverse events. On multivariable Cox analysis, RVD was not associated with adverse events to the contrary to chest tomography severity score > 10 (hazards ratio = 1.70, 95% CI [1.03-2.94]; p = 0.04) and cardiovascular component (> 2) of the SOFA score (HR = 2.93, 95% CI [1.44-5.95], p = 0.003). Right ventricle (RV) dilatation assessed by RV/LV ratio was a common CTPA finding in non-intubated critical patients with COVID-19 pneumonia and was not associated with the occurrence of clinical adverse events.

Effects of nebulized adipose-derived mesenchymal stem cells on acute lung injury following smoke inhalation in sheep

IntroductionTreatment of ARDS caused by smoke inhalation is challenging with no specific therapies available. The aim of this study was to test the efficacy of nebulized adipose-derived mesenchymal stem cells (ASCs) in a well-characterized, clinically relevant ovine model of smoke inhalation injury. Material and MethodsFourteen female Merino sheep were surgically instrumented 5–7 days prior to study. After induction of acute lung injury (ALI) by cooled cotton smoke insufflation into the lungs (under anesthesia and analgesia), sheep were placed on a mechanical ventilator for 48 hrs and monitored for cardiopulmonary hemodynamics in a conscious state. ASCs were isolated from ovine adipose tissue. Sheep were randomly allocated to two groups after smoke injury: 1) ASCs group (n = 6): 10 million ASCs were nebulized into the airway at 1 hr post-injury; and 2) Control group (n = 8): Nebulized with saline into the airways at 1 hr post-injury. ASCs were labeled with green fluorescent protein (GFP) to trace cells within the lung. ASCs viability was determined in bronchoalveolar lavage fluid (BALF). ResultsPaO2/FiO2 in the ASCs group was significantly higher than in the control group (p = 0.001) at 24 hrs. Oxygenation index: (mean airway pressure × FiO2/PaO2) was significantly lower in the ASCs group at 36 hr (p = 0.003). Pulmonary shunt fraction tended to be lower in the ASCs group as compared to the control group. GFP-labelled ASCs were found on the surface of trachea epithelium 48 hrs after injury. The viability of ASCs in BALF was significantly lower than those exposed to the control vehicle solution. ConclusionNebulized ASCs moderately improved pulmonary function and delayed the onset of ARDS.

Bedside electrical impedance tomography (EIT) for early assessment of lung function in liver transplantation.

Early extubation after liver transplantation is recommended by the Enhanced Recovery After Surgery Society (ERAS guideline 2022) as the benefit to avoid prolonged mechanical ventilation and associated complications. The timing of extubation is challenged by early postoperative hypoxia due to both preoperative and surgical status. Timely identifying the cause of hypoxia, typically including hepatopulmonary syndrome (HPS), pulmonary edema, atelectasis, and effusion is critical to prevent delayed extubation, especially in cases with HPS. As a radiation-free bedside approach, electrical impedance tomography (EIT) facilitates real-time lung ventilation and perfusion(V/Q) monitoring, however, the applicability of EIT V/Q monitoring for the assessment of HPS and its value for the management of hypoxia after liver transplantation has never been reported. Under this context, we took the lead in monitoring V/Q with EIT for a 12-year-old girl diagnosed with HPS who suffered intra and post liver transplantation hypoxia at the bedside. Our image raises key points for physicians that: 1) V/Q measurement of intrapulmonary shunts with bedside EIT holds the potential to identify HPS, a novel application that requires clinical validation. 2) EIT helps timely identify hypoxia after liver transplantation to support early individualized respiratory interventions. To our knowledge, V/Q monitoring by EIT is increasingly used in respiratory therapy, especially for ARDS PEEP titration, pulmonary embolism detection and lung transplantation assessment. However, The potential of EIT in liver transplant patients has been rarely studied. Our images might provide a novel and convenient approach to diagnosis HPS at bedside and offer new clinical applications for EIT imaging techniques.

Effect of Balloon Pulmonary Valvuloplasty on Growth of Pulmonary Annulus in Infants with Tetralogy of Fallot.

Percutaneous balloon pulmonary valvuloplasty (PBPV) is an alternative intervention in infants with Tetralogy of Fallot (TOF). It can not only improve hypoxia but also promote pulmonary annulus (PA) growth. In this study, we evaluated the effect of PBPV on PA growth in infants with TOF. To eliminate the effect of the systemic to pulmonary shunt (SPS) that may promote PA growth, we divided TOF infants into 2 groups: group A, patients who underwent PBPV with or without other SPS, and group B, patients who attempted SPS but without PBPV. Sixty patients were included, 28 patients in group A and 32 patients in group B. Age at the time of intervention in group A (range, 0.4-5.4; median 1.4months) was lower than that in group B (range, 2.3-7.7; median 4.8months), p-value 0.02. The body weight in group A (range, 3-5.5; median 3.7kg) was also lower than that in group B (range 4.1-6.4; median 5.9kg), p-value 0.02. Echocardiographic data at the mean follow-up period of 37.2months (3-88months) in group A and 39.6months (6-95months) in group B demonstrated an increase in mean PA diameter from 5.0 ± 1.3mm to 10.2 ± 2.9mm, p-value < 0.001 in group A; and from 6.2 ± 2mm to 9.5 ± 2.9mm, p-value < 0.001 in group B. The median PA z-score increased from -3.4SD (-3.9 to -2.6SD) to -1.8SD (-2.5 to -0.8SD), with the p-value of 0.002 in group A; and increased from -2.9SD (-4.5 to -1.3SD) to -2.7SD (-3.6 to -1.4SD), with the p-value of 0.73 in group B. By using the PA z-score as the absolute value, there was a statistically significant increase in the PA z-score during follow-up in group A, but not in group B. Balloon pulmonary valvuloplasty in infants with TOF can facilitate the growth of the pulmonic annulus even after eliminating the effect of the systemic to pulmonary shunt.

HPC+ in the medical field: Overview and current examples.

To say data is revolutionising the medical sector would be a vast understatement. The amount of medical data available today is unprecedented and has the potential to enable to date unseen forms of healthcare. To process this huge amount of data, an equally huge amount of computing power is required, which cannot be provided by regular desktop computers. These areas can be (and already are) supported by High-Performance-Computing (HPC), High-Performance Data Analytics (HPDA), and AI (together "HPC+"). This overview article aims to show state-of-the-art examples of studies supported by the National Competence Centres (NCCs) in HPC+ within the EuroCC project, employing HPC, HPDA and AI for medical applications. The included studies on different applications of HPC in the medical sector were sourced from the National Competence Centres in HPC and compiled into an overview article. Methods include the application of HPC+ for medical image processing, high-performance medical and pharmaceutical data analytics, an application for pediatric dosimetry, and a cloud-based HPC platform to support systemic pulmonary shunting procedures. This article showcases state-of-the-art applications and large-scale data analytics in the medical sector employing HPC+ within surgery, medical image processing in diagnostics, nutritional support of patients in hospitals, treating congenital heart diseases in children, and within basic research. HPC+ support scientific fields from research to industrial applications in the medical area, enabling researchers to run faster and more complex calculations, simulations and data analyses for the direct benefit of patients, doctors, clinicians and as an accelerator for medical research.

Hypoxia Associated With Dihydropyridine Calcium Channel Inhibitors: A Pharmacovigilance Study in VigiBase.

Due to their negative effects on hypoxic pulmonary vasoconstriction, dihydropyridine calcium channel inhibitors (DCCIs) can lead to hypoxia in patients with a pulmonary shunt. To date, only preclinical studies and case reports have focused on this potential adverse drug reaction. We aimed to assess the reporting association between DCCIs and hypoxia using the World Health Organization pharmacovigilance database (VigiBase). We performed a disproportionality analysis to evaluate the strength of the reporting association between i.v. clevidipine and nicardipine, thought to be a surrogate of patients in the intensive care unit, and hypoxia. The information component and the lower end of its 95% credibility interval were used to evaluate disproportionality. A description of the cases was made. Secondary outcomes included the association between all DCCIs and hypoxia compared with other treatments with similar indications, urapidil and labetalol, regardless of the route of administration. Association between oral nicardipine and hypoxia was also searched. A statistically significant signal of hypoxia was found for intravenous clevidipine and nicardipine. The time to onset was reported with a median of 2 days (interquartile range 1.5-4.5). Four dechallenges were performed with intravenous nicardipine, leading to the resolution of the symptoms. Regardless of the route of administration, a signal of hypoxia was also found for nimodipine but not for other drugs, including comparators. For nicardipine no signal of hypoxia was found with the oral route of administration. Our pharmacovigilance database analysis showed a significant association between the use of intravenous DCCIs and hypoxia.