Pulmonary Arterial Blood Research Articles

A High-Stability Pressure-Sensitive Implantable Memristor for Pulmonary Hypertension Monitoring.

Pulmonary hypertension (PH) significantly affects the quality of life and lifespan of humans and has promoted the development of flexible implantable electronic devices for PH diagnosis and prevention. Traditional implantable devices based on the von Neumann architecture face insurmountable challenges in processing large amounts of biological data due to computational bottlenecks. Memristors, with integrated in-memory sensing and computing capabilities, can effectively eliminate computational bottlenecks and become one of the most promising products in implantable devices for health monitoring. Here, a memristor with the Ag/MnO2/BaTiO3/FTO structure is implemented and implanted into Sprague‒Dawley (SD) rats. With polydimethylsiloxane (PDMS) packaging, the device can be continuously worked in vivo for up to four weeks, demonstrating excellent stability and biocompatibility. Furthermore, a memristive sensor array is designed for pulmonary artery blood pressure monitoring based on the pressure-responsive characteristics of the as-prepared memristive device. The front-end memristive sensor array can collect and feedback pressure signal, while noise reduction is achieved through memristive logic circuits, and ultimately the memristor neural network processes and classifies the information. Therefore, this work demonstrates the potential of implantable memristors for pulmonary artery pressure monitoring and provides new inspiration for the design of efficient, real-time, and reliable implantable pressure monitoring devices in medical health monitoring.

Capnodynamic assessment of mixed venous oxygen saturation in a porcine experimental endotoxemic model.

Sepsis continues to be a major cause of death and illness globally, posing significant challenges for healthcare professionals. In the pursuit of more accurate and timely monitoring tools, the concept of capnodynamically derived mixed venous oxygen saturation (Capno-SvO2) has emerged as a promising method. Capno-SvO2 provides a non-invasive way to assess and track SvO2 and could serve as an additional tool alongside more invasive methods like the pulmonary artery catheter. This could potentially be of great value in the care of critically ill patients with sepsis, where alternative minimal invasive monitoring methods may vary in reliability. The aim of the current study was to compare capno-SvO2 against values obtained through pulmonary artery blood sample CO-oximetry and continuous fiberoptic SvO2 monitoring, using a well-established porcine experimental sepsis model. Anesthetized pigs were exposed to a standardized endotoxin infusion sepsis protocol, followed by a series of maneuvers typically applied in sepsis care. Simultaneous recordings were done throughout the experiment for all three monitoring methods. Bland-Altman analysis corrected for repeated measurements was used to assess the agreement of absolute values between the paired recording of CO-oximetry and Capno-SvO2 as well as between CO-oximetry and fiberoptic SvO2. The ability of Capno-SvO2 and fiberoptic SvO2 to track changes was assessed by concordance rate. A total of 10 animals and 275 paired datapoints were included in the study. The majority of the animals displayed pronounced hemodynamical instability in response to endotoxin exposure and subsequent treatment interventions. Analysis of all paired data points showed a bias between Capno-SvO2 and CO-oximetry SvO2 of + 1% with 95% limits of agreement of -14% to + 17%. The corresponding numbers for fiberoptic SvO2 and CO-oximetry SvO2 were -4% and -15% to + 8%. The concordance rate as compared to CO-oximetry, were 97% and 93% for Capno-SvO2 and fiberoptic SvO2, respectively. In this experimental sepsis model, continuous, non-invasive Capno-SvO2 generates average absolute values comparable to the gold standard CO-oximetry albeit with relatively wide limits of agreement. Capno-SvO2 displayed a concordance rate of 97% against CO-oximetry and exhibits better trending ability compared to invasive fiberoptic SvO2.

Investigating the effects of systemic thrombolysis on electrocardiography and pulmonary artery blood pressure in patients with pulmonary embolism.

We aimed to evaluate the association between electrocardiography (ECG) and echocardiographic findings in patients with pulmonary embolism (PE) before and after systemic thrombolysis. We included 38 PE patients admitted to the hospital with approved right ventricular (RV) dysfunction who were indicated for systemic thrombolysis. Indications for systemic thrombolysis were considered as patients who were either hemodynamically unstable on admission or became unstable in the course of hospital admission. Systemic thrombolysis was performed by either Reteplase or Alteplase. ECG and echocardiographic findings were documented at baseline and 12-24 h following systemic thrombolysis. Our results showed that TAPSE significantly increased while RV size and pulmonary artery systolic pressure (PAP) notably decreased after systemic thrombolysis (p < 0.001). The ECG abnormalities markedly diminished after systemic thrombolysis in PE patients (p < 0.001). Additionally, 100% of our patients had more than one ECG abnormality at baseline, while 55.3% had no ECG abnormalities after systemic thrombolysis. Further, the median number of ECG abnormalities remarkably attenuated after systemic thrombolysis (from 2.0 (1.0) to 0.0 (1.0), p < 0.001). Our results also revealed that delta RV size (r = 0.51, p = 0.001) and delta TAPSE (r = 0.4, p = 0.012) were positively correlated while mortality (r = -0.55, p = 0.001) was negatively associated with changes in the number of ECG abnormalities before and after systemic thrombolysis. We showed that systemic thrombolysis improved echocardiographic and electrocardiographic findings in PE patients. Additionally, a greater decreased number of ECG abnormalities after systemic thrombolysis was accompanied by more improvement in RV size and TAPSE and a lower mortality rate.

Detection of Circulating Tumor Cells and EGFR Mutation in Pulmonary Vein and Arterial Blood of Lung Cancer Patients Using a Newly Developed Immunocytology-Based Platform.

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors are powerful molecular targeted therapeutic agents for lung cancer. We recently developed an original immunocytology and glass slide-based circulating tumor cell (CTC) detection platform for both CTC enumeration and EGFR mutation analysis with DNA extracted from CTCs. Using this platform, we conducted a pilot clinical study for CTC enumeration in peripheral blood (PB), pulmonary arterial blood (PA), and pulmonary venous blood (PV) from 33 patients with lung cancer (Stage I-III) who underwent surgery, followed by digital PCR-based EGFR mutation analysis of CTCs in PV from 12 patients. The results showed that CTC levels were significantly higher in PV and PA than in PB (p < 0.05, p < 0.01. respectively), with a notably greater number of small and large CTC clusters (p < 0.01). Genetic analysis of EGFR mutations of CTCs from PV (n = 12) revealed six mutations, including three Exon19del and three L856R, in CTCs and eight EGFR mutations, including five Exon19del and three L856R, in lung tumor tissue. CTC mutation status matched that of tissue samples in nine patients, was unmatched in two patients, and controversial in one patient, indicating a sensitivity of 0.75 (6/8) and specificity of 1.0 (4/4) with some false-negative results for the mutation analysis of CTCs. This immunocytology-based CTC detection platform is a convenient method for detecting both CTC number and EGFR mutation status under microscopy, suggesting its potential as a liquid biopsy tool in the hospital for patients with lung cancer in some clinical settings.

Novel Drp1 GTPase Inhibitor, Drpitor1a: Efficacy in Pulmonary Hypertension.

Drp1 (dynamin-related protein 1), a large GTPase, mediates the increased mitochondrial fission, which contributes to hyperproliferation of pulmonary artery smooth muscle cells in pulmonary arterial hypertension (PAH). We developed a potent Drp1 GTPase inhibitor, Drpitor1a, but its specificity, pharmacokinetics, and efficacy in PAH are unknown. Drpitor1a's ability to inhibit recombinant and endogenous Drp1 GTPase was assessed. Drpitor1a's effects on fission were studied in control and PAH human pulmonary artery smooth muscle cells (hPASMC) and blood outgrowth endothelial cells (BOEC). Cell proliferation and apoptosis were studied in hPASMC. Pharmacokinetics and tissue concentrations were measured following intravenous and oral drug administration. Drpitor1a's efficacy in regressing monocrotaline-PAH was assessed in rats. In a pilot study, Drpitor1a reduced PA remodeling only in females. Subsequently, we compared Drpitor1a to vehicles in control and monocrotaline-PAH females. Drp1 GTPase activity was increased in PAH hPASMC. Drpitor1a inhibited the GTPase activity of recombinant and endogenous Drp1 and reversed the increased fission, seen in PAH hPASMC and PAH BOEC. Drpitor1a inhibited proliferation and induced apoptosis in PAH hPASMC without affecting electron transport chain activity, respiration, fission/fusion mediator expression, or mitochondrial Drp1 translocation. Drpitor1a did not inhibit proliferation or alter mitochondrial dynamics in normal hPASMC. Drpitor1a regressed monocrotaline-PAH without systemic vascular effects or toxicity. Drpitor1a is a specific Drp1 GTPase inhibitor that reduces mitochondrial fission in PAH hPASMC and PAH BOEC. Drpitor1a reduces proliferation and induces apoptosis in PAH hPASMC and regresses monocrotaline-PAH. Drp1 is a therapeutic target in PAH, and Drpitor1a is a potential therapy with an interesting therapeutic sexual dimorphism.

Validation of a Novel Method for Noninvasive Mixed Venous Oxygen Saturation Monitoring in Anesthetized Children.

Mixed venous oxygen saturation (SvO 2 ) is a critical variable in the assessment of oxygen supply and demand but is rarely used in children due to the invasive nature of pulmonary artery catheters. The aim of this prospective, observational study was to investigate the accuracy of noninvasively measured SvO 2 acquired by the novel capnodynamic method, based on differential Fick equation (Capno-SvO 2 ), against gold standard CO-oximetry. Capno-SvO 2 was compared to SvO 2 measured by pulmonary artery blood gas CO-oximetry in children undergoing cardiac catheter interventions and subjected to moderate hemodynamic challenges. Bland-Altman analysis was used to describe the agreement of absolute values between CO-oximetry and Capno-SvO 2 , and a concordance rate was calculated to evaluate the ability of Capno-SvO 2 to track change. Twenty-five procedures were included in the study. Capno-SvO 2 showed a bias toward CO-oximetry of +3 percentage points; upper and lower limits of agreement were +11 percentage points (95% confidence interval [CI], 9-14) and -5 percentage points (95% CI, -8 to -3), respectively. The concordance rate was 92% (95% CI, 89-96). In conclusion, this first clinical application of a novel concept for noninvasive SvO 2 monitoring without the need for a pulmonary artery catheter indicates that Capno-SvO 2 generates absolute values and trending capacity in close agreement with the gold standard reference method.

Differences in Anthropometric, Sleep and Respiratory Characteristics between Hypercapnic and Normocapnic Patients with COPD-OSA Overlap Syndrome.

Overlap syndrome (OS), the coexistence of chronic obstructive pulmonary disease and obstructive sleep apnea, is frequently characterized by the presence of daytime hypercapnia (pCO2 ≥ 45 mmHg). The aim of this study was to investigate potential differences in anthropometric, sleep and respiratory characteristics between hypercapnic and normocapnic patients with OS. Consecutive patients who underwent polysomnography, pulmonary function testing and arterial blood gases and had been diagnosed with OS were enrolled in the study. According to pCO2 levels in wakefulness, the patients were divided into group A, consisting of OS patients without hypercapnia (n = 108) or group B, consisting of OS patients with hypercapnia (n = 55). The majority of included patients in both groups were males (n = 92 in group A vs. n = 50 in group B). Group B had increased BMI (p = 0.001), neck (p = 0.017) and waist circumference (p = 0.013), higher scores in Epworth sleepiness scale (ESS) (p = 0.008), increased sleep efficiency (p = 0.033), oxygen desaturation index (p = 0.004) and time with oxyhemoglobin saturation <90% (p = 0.006) than group A. Also, Group B had decreased average and minimum oxyhemoglobin saturation during sleep (p < 0.001). Hypercapnic patients had lower FEV1% (p = 0.003), FVC% (p = 0.004), pO2 and pCO2 (p < 0.001 for both) values compared with normocapnic patients. In binary regression analysis, which assessed various predictors on the likelihood of having hypercapnia, it was found that BMI (OR: 1.313, 95% CI: 1.048-1.646, p = 0.018) and FVC (OR: 0.913, 95% CI: 0.845-0.986, p = 0.020) were the major determinants of hypercapnia in OS patients. Hypercapnic OS patients were more obese and sleepy and presented worse respiratory function in wakefulness and sleep hypoxia characteristics compared with normocapnic OS patients.

Involvement of the Lung Parenchyma Analyzed by Frequency Components of the Tidal Volume Assessed by Electrical Bioimpedance

Pulmonary function tests are vital for detecting pathologies, especially chronic obstructive pulmonary diseases (COPD), emphasizing the importance of assessing lung parenchyma involvement in maintaining proper gas exchange. Electrical impedance tomography (EIT) offers a non-invasive alternative for respiratory function evaluation while preserving natural breathing. We propose using EIT to detect lung parenchyma conditions by analyzing tidal volume patterns (by averaging the impedance image) in the frequency domain. Twenty COPD patients underwent simultaneous evaluation with a pneumotachometer and an EIT device, performing three 30-second respiratory maneuvers. FFT spectra analysis yielded parameters, including the area under the curve and quartiles (25 %, 50 %, 75 %) of power values in six frequency regions. Correlations between these parameters and clinical test results (pulmonary diffusing capacity and arterial blood gas analysis) revealed significant associations, particularly with PCO2. Multiple linear regression analysis predicted PCO2 with an R2adj = 0.827, suggesting the potential for non-invasively detecting lung parenchyma affectation by correlating FFT bioimpedance ventilatory patterns with gas exchange performance in COPD patients.

Increased left atrial pressure distorts pulmonary arterial impedance estimates in the low-range of frequency in rats

BACKGROUD: Post-capillary pulmonary hypertension (PH), characterized as increased downstream pressure such as left atrial pressure (LAP), is the most prevalent type of PH and a significant contributor to right heart failure. Accurate estimation of pulmonary arterial characteristics, serving as right ventricular afterload, is crucial for management of PH. These characteristics can be captured comprehensively through pulmonary arterial impedance (PAZ), which elucidates pulmonary arterial pressure-flow relationship within the frequency domain. Although LAP waveforms are potential to affect the contours of pulmonary arterial pressure (PAP) and flow (PAF) waveforms, it remains unknown whether increased LAP affects the accuracy of PAZ measurement. This study aimed to investigate the impact of LAP on the accuracy of PAZ using an acute rodent model. METHODS: We measured pulmonary arterial blood flow (PAF), PAP, and LAP simultaneously in eight male Sprague-Dawley rats. PAZ was calculated as a reciprocal of admittance. Admittance was calculated in the following two ways: 1) one-input (PAP) and one-output (PAF) analysis (I1O1 analysis): the ratio of PAP(f) to PAF(f) at each frequency, where PAP(f) and PAF(f) are frequency spectra of PAP and PAF, respectively, and 2) two-input (PAP and LAP) and one-output (PAF) analysis (I2O1 analysis): excluding the potential effect of LAP from PAP and PAF. We measured PAZ under both normal physiological condition and post-capillary PH condition. To induce acute post-capillary PH by raising LAP &gt;15 mmHg, we ligated aortic arch at the site between brachiocephalic artery and left common carotid artery and performed blood transfusion from a donor rat (TAL/BT). The accuracy of PAZ was examined as the coherence function representing the linearity between the input and output signals. Results: TAL/BT significantly increased LAP from 3 ± 1mmHg to 21 ± 4 mmHg and PAP from 17 ± 3 mmHg to 34 ± 3 mmHg (p&lt;0.01 for both). The I2O1 analysis provided a consistently accurate estimation of PAZ under both normal and elevated LAP conditions with high coherence function (&gt;0.9) in the wide range of frequency between 0.12 and 10.7 Hz. The I1O1 analysis also estimated the PAZ accurately in normal condition with high coherence function (&gt;0.9) in the wide range of frequency, however, the I1O1 analysis overestimated PAZ in the low-range frequency between 0.12 and 1.0 Hz compared with the I2O1 analysis (I1O1: 0.32±0.10 vs. I2O1 0.23±0.06 mmHg/ml/min, p&lt;0.01), with significantly lower coherence function (I1O1: 0.77±0.05 vs. I2O1: 0.96±0.01, p&lt;0.01). CONCLUSION: Increased LAP may have the impact on the accuracy of PAZ estimation in the low-range frequency. The I2O1 analysis can lead to more accurate assessment of right ventricular afterload in post-capillary PH, compared with the I1O1 analysis. Grant-in-Aid for Young Scientists of the Japanese Society of Cardiovascular Anesthesiologists Project Number 2271000048. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Prevalence and Characteristics of Patients with Obstructive Sleep Apnea and Chronic Obstructive Pulmonary Disease: Overlap Syndrome.

Overlap syndrome (OVS) is a distinct clinical entity that seems to result in potential cardiovascular consequences. We aimed to estimate the prevalence and risk factors for OVS in OSA patients and analyze clinical and PSG characteristics associated with OVS. In this cross-sectional study, 2616 patients evaluated for OSA underwent type-1 polysomnography (PSG). They were grouped as pure OSA (AHI > 15/h) and OVS patients. Demographics, PSG data, pulmonary function tests and arterial blood gases (ABGs) were compared between groups after adjustments for confounders. OSA was diagnosed in 2108 out of 2616 patients. Of those, 398 (19%) had OVS. Independent predictors of OVS were older age [OR: 5.386 (4.153-6.987)], current/former smoking [OR: 11.577 (7.232-18.532)], BMI [OR: 2.901 (2.082-4.044)] and ABG measurements [PaCO2 ≥ 45 OR: 4.648 (3.078-7.019), PO2 [OR: 0.934 (0.920-0.949)], HCO3- [OR: 1.196 (1.133-1.263), all p < 0.001]. OVS was also associated with prevalent hypertension [OR: 1.345 (1.030-1.758), p = 0.03] and cardiovascular disease [OR: 1.617 (1.229-2.126), p < 0.001], depressive symptoms [OR: 1.741 (1.230-2.465), p = 0.002] and nocturia [OR: 1.944 (1.378-2.742), p < 0.001], as well as with indices of OSA severity. Disturbances in sleep architecture were more prominent in OVS expressed by lower %N3 and REM% and higher arousal index. Our data suggest that OVS is prevalent among OSA patients, with distinct clinical and PSG characteristics. These characteristics could be utilized as predictive factors for early identification and further evaluation of these patients towards desirable patient-reported outcomes.

Echocardiographic parameters as adjuncts to the Pulmonary Embolism Severity Index in predicting 30-day mortality in acute pulmonary embolism patients.

The Pulmonary Embolism Severity Index (PESI) is a validated tool to predict 30-day all-cause mortality in patients with acute pulmonary embolism (PE) but includes only clinical variables. We aimed to determine the effectiveness of PESI extended with an echocardiographic parameter. This cross-sectional observational study included consecutive patients with acute PE diagnosed with computed tomography pulmonary angiography. Of 117 subjects (57 men, 48.7%), at a median age of 69 (59-80) years, 16 patients died during the 30-day follow-up. Six modified models of PESI with an additional single echocardiographic parameter were created, which increased the predictive value of PESI (area under the curve [AUC] 0.8608): tricuspid annular plane systolic excursion (TAPSE) <18 mm, right ventricular (RV) free wall longitudinal strain (RVFWLS) >-23%, 60/60 sign, RV global longitudinal strain (RVGLS) >-16%, pulmonary ejection acceleration time (AcT) <67 ms, and thrombus in right heart cavities (AUC 0.8657 to 0.8976, respectively, all markers P <0.001). TAPSE, AcT, RVFWLS, and RVGLS showed significant correlations with the PESI score, but not a thrombus in the right heart cavity or the 60/60 sign. As PESI adjuncts, they independently predicted fatal outcomes: thrombus with hazard ratio (HR) 10.04 (95% confidence interval [CI], 2.81-37.12; P <0.001) and the 60/60 sign with HR 4.07 (95% CI, 1.27-12.81; P <0.001). The quantitative echocardiographic parameters of RV systolic function and pulmonary artery blood flow are associated with the PESI score and thus increase its predictive value to a limited extent. PE- specific findings: a thrombus in the right heart cavity and the 60/60 sign are effective adjuncts to the PESI score.

Anesthesia management of laparoscopic right colectomy in an older patient with postoperative tetralogy of Fallot with residual anomaly

BackgroundDiversity in hemodynamics of adult congenital heart disease necessitates a case-by-case selection of appropriate surgical and anesthetic options. However, previous case reports regarding the management of laparoscopic surgery in adult patients with congenital heart disease are limited.Case presentationA 72-year-old man who underwent a laparoscopic right colectomy for colon cancer had a residual ventricular septal defect and right ventricular outflow tract obstruction despite post-repair of tetralogy of Fallot. Pulmonary hypertension or right ventricular dysfunction was not observed. The preoperative pulmonary to systemic blood flow ratio (Qp/Qs) was 2.3. After positive pressure ventilation and insufflation, the amount of left-to-right ventricular shunting decreased, and the Qp/Qs approached 1.0, as calculated from pulmonary arterial and systemic arterial blood gas analysis.ConclusionsLaparoscopic surgery might be tolerable in patients with tetralogy of Fallot who have preserved the right ventricular function, left-to-right ventricular shunting, and no high pulmonary vascular resistance.

Pharmacokinetics of desflurane uptake and disposition in piglets.

Many respiratory but few arterial blood pharmacokinetics of desflurane uptake and disposition have been investigated. We explored the pharmacokinetic parameters in piglets by comparing inspiratory, end-tidal, arterial blood, and mixed venous blood concentrations of desflurane. Seven piglets were administered inspiratory 6% desflurane by inhalation over 2h, followed by a 2-h disposition phase. Inspiratory and end-tidal concentrations were detected using an infrared analyzer. Femoral arterial blood and pulmonary artery mixed venous blood were sampled to determine desflurane concentrations by gas chromatography at 1, 3, 5, 10, 20, 30, 40, 50, 60, 80, 100, and 120min during each uptake and disposition phase. Respiratory and hemodynamic parameters were measured simultaneously. Body uptake and disposition rates were calculated by multiplying the difference between the arterial and pulmonary artery blood concentrations by the cardiac output. The rates of desflurane body uptake increased considerably in the initial 5min (79.8ml.min-1) and then declined slowly until 120min (27.0ml.min-1). Similar characteristics of washout were noted during the subsequent disposition phase. Concentration-time curves of end-tidal, arterial, and pulmonary artery blood concentrations fitted well to zero-order input and first-order disposition kinetics. Arterial and pulmonary artery blood concentrations were best fitted using a two-compartment model. After 2h, only 21.9% of the desflurane administered had been eliminated from the body. Under a fixed inspiratory concentration, desflurane body uptake in piglets corresponded to constant zero-order infusion, and the 2-h disposition pattern followed first-order kinetics and best fitted to a two-compartment model.

Echocardiographic assessment of cardiovascular involvements in children with cystic fibrosis

BackgroundOver the past four decades, numerous case reports and clinical studies have highlighted the presence of heart disease in individuals with cystic fibrosis. Given the limited information in this field and the imperative to identify early changes during childhood, our study aims to explore cardiac dysfunction in patients with cystic fibrosis using echocardiography. MethodsIn this case-control study, we examined echocardiographic findings from thirty-three patients with cystic fibrosis and sixty healthy children. Demographic information for both groups was recorded, and the disease severity in patients was assessed using the Schawachman criterion. M-mode, Doppler flow velocity, and Tissue Doppler Imaging echocardiography were performed for all participants, with subsequent data analysis using SPSS 24. ResultsOur study encompassed thirty-three CF patients and sixty healthy children. The estimated pulmonary artery blood pressure (systolic and mean) in patients with cystic fibrosis was significantly higher than in the control group (P < 0.05). Additionally, the mean trans-tricuspid peak early to late diastolic flow velocity (E/A) was significantly lower in the case group than the control group (P < 0.05), along with a significantly lower mean tricuspid valve deceleration time (DT) (P < 0.05). Similarly, the mean TAPSE in the case group was notably lower than in the control group (P < 0.05). No significant difference in Mean left ventricular Ejection Fraction (EF) and Fractional Shortening (FS) existed between the two groups (P > 0.05). Furthermore, Trans-mitral peak early to late diastolic flow velocity (E/A) in the case group was significantly lower than in the control group (P < 0.05), and the mean mitral valve DT in the case group was also significantly lower (P < 0.05). ConclusionOur study findings indicate the presence of some degree of right ventricular dysfunction in children with cystic fibrosis. This finding may have implications for the development or modification of clinical guidelines for managing cystic fibrosis in children. Further investigations are recommended to elucidate the underlying mechanisms and contributing factors, providing valuable insights for clinical management.

Extended period of ventilation before delayed cord clamping augments left-to-right shunting and decreases systemic perfusion at birth in preterm lambs.

Previous studies have suggested that an extended period of ventilation before delayed cord clamping (DCC) augments birth-related rises in pulmonary arterial (PA) blood flow. However, it is unknown whether this greater rise in PA flow is accompanied by increases in left ventricular (LV) output and systemic arterial perfusion or whether it reflects enhanced left-to-right shunting across the ductus arteriosus and/or foramen ovale (FO), with decreased systemic arterial perfusion. Using an established preterm lamb birth transition model, this study compared the effect of a short (∼40s, n=11), moderate (∼2min, n=11) or extended (∼5min, n=12) period of initial mechanical lung ventilation before DCC on flow probe-derived perinatal changes in PA flow, LV output, total systemic arterial blood flow, ductal shunting and FO shunting. The LV output was relatively stable during initial ventilation but increased after DCC, with similar responses in all groups. Systemic arterial flow patterns displayed only minor differences during brief and moderate periods of initial ventilation and were similar after DCC. However, an increase in PA flow was augmented with an extended initial ventilation (P < 0.001), owing to an earlier onset of left-to-right ductal and FO shunting (P < 0.001), and was accompanied by a pronounced reduction in total systemic arterial flow (P=0.005) that persisted for 4min after DCC (P ≤ 0.039). These findings suggest that, owing to increased left-to-right shunting and a greater reduction in systemic arterial perfusion, an extended period of ventilation before DCC does not result in greater perinatal circulatory benefits than shorter periods of initial ventilation in the birth transition. KEY POINTS: Previous studies suggest that an extended period of initial ventilation before delayed cord clamping (DCC) augments birth-related rises in pulmonary arterial (PA) blood flow. It is unknown whether this greater rise in PA flow is accompanied by an increased left ventricular output and systemic arterial perfusion or whether it reflects enhanced left-to-right shunting across the ductus arteriosus and/or foramen ovale, with decreased systemic arterial perfusion. Anaesthetized preterm fetal lambs instrumented with central arterial flow probes underwent a brief (∼40s), moderate (∼2min) or extended (∼5min) period of ventilation before DCC. Perinatal changes in left ventricular output were similar in all groups, but extended initial ventilation augmented both perinatal increases in PA flow, owing to earlier onset and greater left-to-right ductal and foramen ovale shunting, and perinatal reductions in total systemic arterial perfusion. Extended ventilation before DCC does not confer a greater perinatal circulatory benefit than shorter periods of initial ventilation.

A study on the outcome of preoperative pulmonary function tests on a patient undergoing rheumatic mitral valve surgery.

Evaluation of pulmonary function by spirometer in adult patients undergoing cardiac surgery is a simple test to assess pulmonary reserve that has important implications in operative morbidity. However, there is no established consensus regarding which patients should undergo preoperative pulmonary function tests (PFTs), including forced expiratory volume in the first second (FEV1) and forced vital capacity (FVC). The primary aim was to evaluate the outcome of preoperative PFTs on patients undergoing rheumatic mitral valve surgery. One hundred patients undergoing rheumatic mitral valve surgery, meeting the inclusion criteria, were included in this prospective observational study. The pulmonary function of the patients was assessed using a spirometer before surgery. Preoperative pulmonary artery systolic pressure (PASP) and arterial blood gas (ABG) analyses were also performed. The correlation of PFTs with early postsurgical outcome, comprising mortality within 30 days of surgery and morbidity defined as the existence of at least one of the postoperative complications, such as low cardiac output state indicated by increased requirement of inotropes, prolonged ventilation (>24 hours), postoperative new-onset hemodynamically significant arrhythmias, renal dysfunction, and post-op infection, was assessed. With the increasing New York Heart Association (NYHA) class of the patient, there was a decline of FEV1% and FVC%, which was statistically significant (P < 0.0001). There was a significant positive correlation of FVC% with preoperative saturation of peripheral oxygen (SpO2) and preoperative saturation of peripheral carbon dioxide (PaO2) and FEV1% with preoperative SpO2 and preoperative PaO2. Patients who had postoperative prolonged ventilation had lower values of FVC% and FEV1%, which was statistically significant (P < 0.001). The patients who expired had significantly lower values of FVC% and FEV1%. Preoperative lung function has an implication on intraoperative morbidity during cardiac surgery although a common consensus on its application is lacking. Preoperative spirometry can be one of the parameters for predicting postoperative morbidity and mortality in patients undergoing rheumatic mitral valve surgery. Spirometry might have a role to play in predicting patient outcomes in rheumatic mitral valve surgeries; however, larger well-powered studies are needed.

Management of a child with portopulmonal hypertension due to cavernous transformation of the portal vein and sple- norenal anastomosis

A clinical case of the development of portopulmonary hypertension in a child after splenorenal anastomosis is presented. The surgical intervention was performed to correct the congenital malformation — cavernous transformation of the portal vein, which led to portal hypertension and varicose veins of the esophagus and stomach. In the long-term postoperative period, pulmonary arterial hypertension, hypersplenism with bilinear cytopenia, and moderate liver failure developed. Combined therapy provided a temporary improvement of the patient status, therefore, during subsequent surgery, the size of the anastomosis was changed. This led to a sustained decrease in pulmonary artery blood pressure and clinical improvement in the boy’s condition.

Leukotriene B4 levels in CHD-associated paediatric pulmonary hypertension.

The aim of this study is to evaluate the role of leukotriene B4, an inflammatory mediator, in the development of pulmonary hypertension in paediatric patients with CHD with left-right shunt. The study included forty patients with CHD with left-right shunts. Based on haemodynamic data obtained from cardiac diagnostic catheterisation, 25 patients who met the criteria for pulmonary arterial hypertension were included in the patient group. The control group comprised 15 patients who did not meet the criteria. The standard cardiac haemodynamic study was conducted. Leukotriene B4 levels were assessed in blood samples taken from both pulmonary arteries and peripheral veins. The median age of patients with pulmonary arterial hypertension was 10 months (range: 3-168), while the median age of the control group was 50 months (range: 3-194). In the pulmonary hypertension group, the median pulmonary artery systolic/diastolic/mean pressures were 38/18/24 mmHg, compared to 26/10/18 mmHg in the control group. Leukotriene B4 levels in pulmonary artery blood samples were significantly higher in the pulmonary arterial hypertension group compared to the controls (p < 0.05). Peripheral leukotriene B4 levels were also elevated in the pulmonary arterial hypertension group in comparison to the control group, though the difference was not statistically significant. The discovery of elevated leukotriene B4 levels in pulmonary artery samples from paediatric patients with pulmonary arterial hypertension secondary to CHD with left-to-right shunt suggests that local inflammation may have a pathological role in the development of pulmonary arterial hypertension.

Pulmonary blood flow in children with univentricular heart and unilateral diaphragmatic paralysis.

Spontaneous breathing has an important effect on pulmonary arterial blood flow in patients with Glenn/Fontan circulation. Unilateral diaphragmatic paralysis (DP) is a frequent complication after heart surgery in congenital heart disease. The aim of this study was to investigate the influence of unilateral DP on blood flow distribution in the pulmonary arteries with Glenn/Fontan circulation. Magnetic resonance phase-contrast imaging was used to evaluate stroke volume index (SVI) in the left and right pulmonary arteries in patients with Glenn/Fontan circulation with unilateral DP. Data for 18 patients with univentricular heart and unilateral DP were analysed, 8 in the Glenn stage and 10 in the Fontan stage. Ten patients had right-sided DP, and 8 had left-sided DP. A diaphragmatic plication was performed in 7 patients. The control group consisted of 36 patients with Glenn (n = 16)/Fontan (n = 20) circulation without DP. In both left- and right-sided DP, the SVI to the ipsilateral side was significantly lower than in controls [2.81 (1.45-4.50) ml/m2 left vs 11.97 (7.36-16.37) ml/m2 in controls, P < 0.0002; 8.2 (4.49-12.64) ml/m2 with right vs 12.64 (9.66-16.61) ml/m2 in controls; P = 0.0284]. The SVI to the contralateral side showed a slight but non-significant increase in the presence of unilateral DP. Unilateral DP in patients with Glenn/Fontan circulation has a negative impact on pulmonary arterial SVI on the side of the paralysis.

Pulmonary Dysfunction in Patients with Cirrhosis of the Liver: A Study of Pulmonary Function Tests and Arterial Blood Gases.

Respiratory complications in liver cirrhosis can occur due to various mechanisms, such as ascites causing restricted lung expansion and opening of intrapulmonary vascular shunts due to high portal pressures. We aimed to study the effects of the liver dysfunction on the lungs by evaluating arterial blood gas (ABG) and pulmonary function test (PFT) of all study subjects. A cross-sectional study was done between August 2020 and September 2022. Diagnosed cases of the liver cirrhosis were enrolled in the study after informed consent and were subjected to the following investigations: chest X-ray, oximetry, spirometry, diffusing capacity of the lung for carbon monoxide (DLCO), two-dimensional echocardiography, and ABG analysis (ABGA). The cases were divided into three groups based on their Child-Pugh staging, and statistical analysis was done on the collected data. A total of 64 (53 males and 11 females) patients with an average age of 49.82 ± 9.89 years were studied. Alcoholism was the most common cause of cirrhosis in males. Breathlessness (65.6%) and pleural effusion (26.6%) were the most common respiratory symptoms and signs, respectively. Seventeen patients had hepatic hydrothorax, eight patients had hepatopulmonary syndrome (HPS), and six patients had portopulmonary hypertension. Low pH (17.2%) and oxygen partial pressure (PaO2) (20.3%) were the most common ABGA findings. The pH, PaO2, forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC), and DLCO were significantly low in Child Pugh Stage C (P < 0.05). The pH, pO2, HCO3, FEV1, FVC, FEV1/FVC, and DLCO were significantly lower in patients with HPS (P < 0.05). Metabolic acidosis and low FEV1/FVC and DLCO were the common findings in study subjects. Pulmonary dysfunction was common in advanced liver cirrhosis. Patients with HPS had worse ABG and PFT parameters than those without HPS.