Pulmonary Shunt Fraction Research Articles

Effects of Dexmedetomidine in Improving Oxygenation and Reducing Pulmonary Shunt in High-Risk Pediatric Patients Undergoing One-Lung Ventilation for Thoracic Surgery: A Double-Blind Randomized Controlled Trial.

Background and objectives Pediatric thoracic surgery has unique considerations due to the immaturity of the respiratory system anatomically and physiologically, which presents technical and pharmacological considerations, including the very common technique of one-lung ventilation (OLV), which causes serious complications in children. Therefore, we investigated the effects of dexmedetomidine on oxygenation and pulmonary shunt fraction (Qs/Qt) in high-risk pediatric patients undergoing OLV for thoracic surgery. This randomized controlled trial aimed to investigate dexmedetomidine's effect on the partial pressure of arterial oxygen (PaO2) and pulmonary shunt fraction (Qs/Qt). Methods A total of 63 children underwent thoracic surgery with OLV and were divided into two groups. The dexmedetomidine group (group Dex, n = 32) received dexmedetomidine (0.4 μg/kg/hour), and the placebo group (group placebo, n = 31) received normal saline. Two arterial and central venous blood samples were taken for arterial and venous blood gas analysis at four time points: T1 (10 minutes after mechanical ventilation of total lung ventilation), T2 (10 minutes after OLV), T3 (60 minutes after OLV), and T4 (20 minutes after the end of OLV). At these intervals, the following parameters were measured: PaO2, Qs/Qt, mean arterial pressure (MAP), heart rate (HR), and peak inspiratory pressure (PIP). Results The two groups had no significant differences in FEV1/FVC and baseline pulmonary shunt fraction (Qs/Qt). Dexmedetomidine significantly improved PaO2 compared with placebo during OLV (T2 and T3). There was a significant decrease in Qs/Qt compared with placebo during OLV (T2, T3, and T4). There was a decrease in PIP compared with placebo during OLV (T2 and T3). No statistically significant differences in MAP or HR were observed between the groups. Conclusion Infusion of dexmedetomidine during OLV in high-risk pediatric thoracic surgery reduces shunt and pulmonary shunt fraction Qs/Qt, improves PaO2 and body oxygenation, reduces PIP and pressure load, and maintains hemodynamic stability (MAP, HR).

Pressure Support Ventilation During Extracorporeal Membrane Oxygenation Support in Patients With Acute Respiratory Distress Syndrome.

In the initial phases of veno-venous extracorporeal membrane oxygenation (VV ECMO) support for severe acute respiratory distress syndrome (ARDS), ultraprotective controlled mechanical ventilation (CMV) is typically employed to limit the progression of lung injury. As patients recover, transitioning to assisted mechanical ventilation can be considered to reduce the need for prolonged sedation and paralysis. This study aimed to evaluate the feasibility of transitioning to pressure support ventilation (PSV) during VV ECMO and to explore variations in respiratory mechanics and oxygenation parameters following the transition to PSV. This retrospective monocentric study included 191 adult ARDS patients treated with VV ECMO between 2009 and 2022. Within this population, 131 (69%) patients were successfully switched to PSV during ECMO. Pressure support ventilation was associated with an increase in respiratory system compliance (p = 0.02) and a reduction in pulmonary shunt fraction (p < 0.001). Additionally, improvements in the cardiovascular Sequential Organ Failure Assessment score and a reduction in pulmonary arterial pressures (p < 0.05) were recorded. Ninety-four percent of patients who successfully transitioned to PSV were weaned from ECMO, and 118 (90%) were discharged alive from the intensive care unit (ICU). Of those who did not reach PSV, 74% died on ECMO, whereas the remaining patients were successfully weaned from extracorporeal support. In conclusion, PSV is feasible during VV ECMO and potentially correlates with improvements in respiratory function and hemodynamics.

Effect of Dexmedetomidine on Oxygen and Intrapulmonary Shunt (Qs/Qt) During One-Lung Ventilation in Pediatric Surgery: A Randomized Controlled Trial.

Background One-lung ventilation (OLV) is a common ventilation technique used during thoracic surgery. It can cause serious complications in children, and hypoxic pulmonary vasoconstriction (HPV) is a protective mechanism against the resulting hypoxia.Dexmedetomidine does not affect HPV, so we will investigate its impact on the partial pressure of oxygen in arterial blood (PaO2) and pulmonary shunt fraction (Qs/Qt). Methods Children who underwent OLV were divided into two equal groups. The Dex group received 0.4 μg/kg/h of dexmedetomidine intravenously. The placebo group received normal saline. Two blood samples were taken to analyze arterial and central venous blood gasses during four time periods: T1, 10 minutes after anesthesia; T2, 10 minutes after OLV; T3, 60 minutes after OLV; and T4, 20 minutes after the end of OLV. Heart rate, mean arterial pressure (MAP), PaO2, Qs/Qt, and peak inspiratory pressure (PIP) values were recordedat these time points. Results Regarding heart rate, the Dex group remained relatively stable, whereas the placebo group showed a slight increase in T3 and T4. Concerning MAP, theDex group had a reduction at T1 compared with the placebo group and remained similar for other points. PaO2 decreased with OLV. However, the Dex group consistently maintained higher PaO2 values than the placebo, especially in T3 and T4. Concerning Qs/Qt, the Dex group maintained lower time values than the placebo group at OLV. Regarding PIP, the Dex group had significantly lower T2 and T3 than the placebo group. Conclusion Administration ofdexmedetomidine inchildren with OLV improves PaO2 and reduces pulmonary shunt fraction (Qs/Qt), thereby improving oxygen transport. It reduces the maximum PIP values, thereby reducing pressure-related complications.

Effect of ultrasound-guided stellate ganglion block on lung protection for patients undergoing one-lung ventilation.

To explore the potential effect of ultrasound-guided stellate ganglion block (SGB) on lung protection for patients undergoing one-lung ventilation (OLV). A total of 123 patients undergoing elective one-lung ventilation surgery were selected as research subjects in this prospective study. These patients were randomly divided into the SGB group, control group and blank group on average. Stellate ganglion block was carried out in the SGB and control groups. Patients in the SGB group were injected with 6 ml mixture of 0.25% ropivacaine hydrochloride and 1% lidocaine hydrochloride, while those in the control group were injected with 6 mL of 0.9% saline. Punctures weren't performed for patients in the blank group. The same induction and maintenance of general anesthesia was adopted for all three groups. Hemodynamics, respiratory parameters and arterial blood gas analysis were recorded after entering the operation room (T0), pre-OLV (T1), 30 min after OLV (T2), 60 min after OLV (T3), at the end of surgery (T4), and 30 min after extubation (T5). Oxygenation index (OI), pulmonary shunt fraction (Qs/Qt) and pH value were compared at different time points. Intravenous serum was collected at T0, T3 and T5 for the detection of surfactant proteins A (SP-A), superoxide dismutase (SOD), malondialdehyde (MDA), interleukin-6 (IL-6) and interleukin-10 (IL-10) levels, respectively. The complications related to SGB after surgery and the postoperative pulmonary complications within 72 h were recorded. At T1, T2, and T3, MAP level in SGB group was lower than that in blank and control groups (P<0.05). At T2, and T3, SGB group had lower hear rate (HR), peak airway pressure (Ppeak) and tidal volume (TV) than blank and control groups (all P<0.05). From T2 to T5, SGB group had higher OI but lower Qs/Qt than blank and control groups (both P<0.05). At T3 and T5, SGB group had lower SP-A, IL-6, and MDA levels but higher IL-10 and SOD levels than blank and control groups (all P<0.05). There was one case of hypoxemia in the blank group within 72 h after surgery. Ultrasound-guided SGB has lung-protective effects on patients undergoing OLV, which significantly improves patients' OI, reduces intrapulmonary shunts, declines ventilator-induced lung damage, and inhibits inflammatory response as well as oxidative stress (China Clinical Trial Registry, registration number ChiCTR2000033385, https://www.chictr.org.cn).

Improved oxygenation in prone positioning of mechanically ventilated patients with COVID-19 acute respiratory distress syndrome is associated with decreased pulmonary shunt fraction: a prospective multicenter study

BackgroundProne position is used in acute respiratory distress syndrome and in coronavirus disease 2019 (Covid-19) acute respiratory distress syndrome (ARDS). However, physiological mechanisms remain unclear. The aim of this study was to determine whether improved oxygenation was related to pulmonary shunt fraction (Q’s/Q’t), alveolar dead space (Vd/Vtalv) and ventilation/perfusion mismatch (V’A/Q’).MethodsThis was an international, prospective, observational, multicenter, cohort study, including six intensive care units in Sweden and Poland and 71 mechanically ventilated adult patients.ResultsProne position increased PaO2:FiO2 after 30 min, by 78% (83–148 mm Hg). The effect persisted 120 min after return to supine (p < 0.001). The oxygenation index decreased 30 min after prone positioning by 43% (21–12 units). Q’s/Q’t decreased already after 30 min in the prone position by 17% (0.41–0.34). The effect persisted 120 min after return to supine (p < 0.005). Q’s/Q’t and PaO2:FiO2 were correlated both in prone (Beta -137) (p < 0.001) and in the supine position (Beta -270) (p < 0.001). V’A/Q’ was unaffected and did not correlate to PaO2:FiO2 (p = 0.8). Vd/Vtalv increased at 120 min by 11% (0.55–0.61) (p < 0.05) and did not correlate to PaO2:FiO2 (p = 0.3). The ventilatory ratio increased after 30 min in the prone position by 58% (1.9–3.0) (p < 0.001). PaO2:FiO2 at baseline predicted PaO2:FiO2 at 30 min after proning (Beta 1.3) (p < 0.001).ConclusionsImproved oxygenation by prone positioning in COVID-19 ARDS patients was primarily associated with a decrease in pulmonary shunt fraction. Dead space remained high and the global V’A/Q’ measure could not explain the differences in gas exchange.

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.

Cabin Pressure Altitude Effect on Acceleration Atelectasis After Agile Flight Breathing 60% Oxygen.

INTRODUCTION: A flight trial was conducted to determine whether breathing 60% oxygen during high performance flight maneuvers using contemporary pilot flight equipment induces atelectasis and to explore whether cabin altitude had any influence on the extent of atelectasis identified.METHODS: On 2 separate days, 14 male aircrew flew as passengers at High [14,500-18,000 ft (4420-5486 m)] and Low [4000-6000 ft (1219-1829 m)] cabin pressure altitude in a Hawk T Mk1 aircraft breathing 60% oxygen. Sorties comprised 16 maneuvers at +5 Gz, each sustained for 30 s. Lung volumes (spirometry), basal lung volume (electrical impedance tomography, EIT), and peripheral oxygen saturation during transition from hyperoxia to hypoxia (pulmonary shunt fraction) were measured in the cockpit immediately before (Pre) and after (Post) flight.RESULTS: Forced inspiratory vital capacity (FIVC) was significantly lower Postflight after High (-0.24 L) and Low (-0.38 L) sorties, but recovered to Preflight values by the fourth repeat (FIVC4). EIT-derived measures of FIVC decreased after High (-3.3%) and Low (-4.4%) sorties but did not recover to baseline by FIVC4. FIVC reductions were attributable to decreased inspiratory capacity. Spo₂ was lower Postflight than Preflight in High and Low sorties.DISCUSSION: Breathing 60% oxygen during flight results in a 3.8-4.9% reduction in lung volume associated with a small decrease in blood oxygenation and an estimated pulmonary shunt of up to 5.7%. EIT measures suggest persisting airway closure despite repeated FIVC maneuvers. There was no meaningful influence of cabin pressure altitude. The operational consequence of the observed changes is likely to be small.Tank H, Kennedy G, Pollock R, Hodkinson P, Sheppard-Hickey R-A, Woolford J, Green NDC, Stevenson A. Cabin pressure altitude effect on acceleration atelectasis after agile flight breathing 60% oxygen. Aerosp Med Hum Perform. 2023; 94(1):3-10.

Assessment of the Budesonid Protective Effects in Patients with Cardio-Respiratory Comorbidity During Coronary Bypassing with Artificial Circulation

The objective: evaluation of the effect of budesonide and low-volume mechanical ventilation (LVMV) on pulmonary volemia, oxygen transport and respiratory biomechanics in patients with concurrent ischemic heart disease (IHD) and chronic obstructive pulmonary disease (COPD) during coronary artery bypass grafting (CABG) with artificial circulation (AC).Subjects and Methods. 50 patients with concurrent IHD and COPD were enrolled in the study. During AC, patients of Group I (20 people) received mechanical ventilation with the peak inspiratory pressure of 15 mbar, tidal volume of 3‒4 ml/kg, positive end-expiratory pressure of 5 mbar in combination with inhalation of nebulized budesonide. In Group II (30 people), the similar isolated respiratory support was provided. Pulmonary blood volume, indices of extravascular lung water (EVLW), pulmonary vascular permeability (PVPI), oxygen delivery (DO2I) and consumption (VO2I), oxygen extraction ratio (O2ER), pulmonary shunt fraction (Qs/Qt), oxygenation index were determined. The study consisted of 3 stages: before AC, after its completion and one day after CABG.Results. Before CABG, the EVLW index in all patients exceeded the standard level by 67‒72%. After weaning from AC, it decreased by 23% in Group I and by 8% in Group II. In patients receiving budesonide, PVPI significantly decreased after artificial circulation, while in patients from Group II, it remained unchanged. DO2I and O2ER in all patients were within the reference range, and VO2I was below it with a minimum value in Group II after weaning from AC. In this cohort, the Qs/Qt level was significantly higher, while OI was lower versus patients from Group I. Among patients who received budesonide immediately after AC and 2 hours after it, pulmonary resistance decreased while lung compliance increased. In Group II, those parameters changed oppositely. In Group I, one case of hydrothorax was recorded, and in Group II, 2 patients were diagnosed with polysegmental pneumonia and 2 patients – with pneumothorax. The median duration of mechanical ventilation in the postoperative period made 220 minutes in Group I, and 290 minutes in Group II (p = 0.018).Conclusion. In patients with concurrent IHD and COPD, use of the combination of low-volume mechanical ventilation and inhalation of nebulized budesonide during AC stabilizes the volemic status of the lungs, improves the oxygenating function and respiratory biomechanics in the postperfusion and early postoperative periods of CABG.

Effects of Iloprost on Oxygenation during One-Lung Ventilation in Patients with Low Diffusing Capacity for Carbon Monoxide: A Randomized Controlled Study.

The protective mechanism of hypoxic pulmonary vasoconstriction during one-lung ventilation (OLV) is impaired in patients with a low diffusing capacity for carbon monoxide (DLCO). We hypothesized that iloprost inhalation would improve oxygenation and lung mechanics in patients with low DLCO who underwent pulmonary resection. Forty patients with a DLCO < 75% were enrolled. Patients were allocated into either an iloprost group (ILO group) or a control group (n = 20 each), in which iloprost and saline were inhaled, respectively. The partial pressure of arterial oxygen/fraction of inspired oxygen (PaO2/FiO2) ratio, pulmonary shunt fraction, alveolar dead space, dynamic compliance, and hemodynamic parameters were assessed 20 min after the initiation of OLV and 20 min after drug administration. Repeated variables were analyzed using a linear mixed model between the groups. Data from 39 patients were analyzed. After iloprost inhalation, the ILO group exhibited a significant increase in the PaO2/FiO2 ratio and a decrease in alveolar dead space compared with the control group (p = 0.025 and p = 0.042, respectively). Pulmonary shunt, dynamic compliance, hemodynamic parameters, and short-term prognosis were comparable between the two groups. Selective iloprost administration during OLV reduced alveolar dead space and improved oxygenation while minimally affecting hemodynamics and short-term prognosis.

Arteriovenous shunt fraction as a marker for early diagnosis of acute respiratory distress syndrome against the background of cardiogenic pulmonary edema: a case report

Introduction . In recent years, there has been a trend towards an increase in the use of mechanical ventilation (MV) in patients with acute myocardial infarction and cardiogenic shock. Probably, currently there is an underdiagnosis of acute respiratory distress syndrome (ARDS) against the background of cardiogenic pulmonary edema, which does not allow timely use of effective treatment strategies. We propose to use the pulmonary shunt fraction (Qs/Qt) as an additional diagnostic method. Case . A 70-year-old male patient entered the сardiovascular intensive care unit with acute ST-segment elevation myocardial infarction complicated by cardiogenic shock. Emergency percutaneous coronary intervention 50 minutes after hospitalization allowed revascularization of the infarct-related coronary artery and 1:1 intra-aortic balloon counterpulsation was initiated. Against the background of non-invasive ventilation, paraclinical signs of severe respiratory failure persisted — S/F (SpO 2 /FiO 2 ): 108, PaO 2 / FiO 2 (Horowitz index): 78-103, Qs/Qt: 27,3-48,3%). Therefore, MV was started. According to the obtained data (24 hours from the admission), severe ARDS was verified. Renal replacement therapy session was started for non-renal indications. On the 4th day of hospitalization, therapy improved the patient’s condition. A 63-hour session of renal replacement therapy was completed. Against the background of gradual weaning from mechanical ventilation, the patient was extubated. Conclusion . In the above case, the use of shunt fraction (Qs/Qt) contributed to the earliest possible verification of ARDS before the onset of full-scale clinical picture, an increase in biochemical markers and X-ray abnormalities, which made it possible to start targeted therapy in a timely manner.

Hemodynamic response to positive end-expiratory pressure and prone position in COVID-19 ARDS

BackgroundUse of high positive end-expiratory pressure (PEEP) and prone positioning is common in patients with COVID-19-induced acute respiratory failure. Few data clarify the hemodynamic effects of these interventions in this specific condition. We performed a physiologic study to assess the hemodynamic effects of PEEP and prone position during COVID-19 respiratory failure. MethodsNine adult patients mechanically ventilated due to COVID-19 infection and fulfilling moderate-to-severe ARDS criteria were studied. Respiratory mechanics, gas exchange, cardiac output, oxygen consumption, systemic and pulmonary pressures were recorded through pulmonary arterial catheterization at PEEP of 15 and 5 cmH2O, and after prone positioning. Recruitability was assessed through the recruitment-to-inflation ratio. ResultsHigh PEEP improved PaO2/FiO2 ratio in all patients (p = 0.004), and significantly decreased pulmonary shunt fraction (p = 0.012), regardless of lung recruitability. PEEP-induced increases in PaO2/FiO2 changes were strictly correlated with shunt fraction reduction (rho=-0.82, p = 0.01). From low to high PEEP, cardiac output decreased by 18 % (p = 0.05) and central venous pressure increased by 17 % (p = 0.015).As compared to supine position with low PEEP, prone positioning significantly decreased pulmonary shunt fraction (p = 0.03), increased PaO2/FiO2 (p = 0.03) and mixed venous oxygen saturation (p = 0.016), without affecting cardiac output. PaO2/FiO2 was improved by prone position also when compared to high PEEP (p = 0.03). ConclusionsIn patients with moderate-to-severe ARDS due to COVID-19, PEEP and prone position improve arterial oxygenation. Changes in cardiac output contribute to the effects of PEEP but not of prone position, which appears the most effective intervention to improve oxygenation with no hemodynamic side effects.

Influência do decúbito na ocorrência de shunt pulmonar em ovinos anestesiados com sevoflurano

ABSTRACT: This study assessed the impact of different recumbency on sevoflurane-anaesthetised sheep. Seven female sheep were premedicated with 0.1 mg.kg-1 butorfanol and subsequently administered a combination of 3 mg.kg-1 ketamine and 0.5 mg.kg-1 midazolam. Animals were maintained on sevoflurane anaesthesia with pressure-controlled ventilation (12 cm H2O peak inspiratory pressure) and ƒ of 10 mpm. During the anaesthetic procedure, animals underwent one out of three different recumbency: dorsal, left lateral, or right lateral positions. Treatments lasted 120 min with a 48-h washout period in between the treatments. Arterial and central venous blood samples were withdrawn for blood gas and electrolytes analysis and pulmonary shunt fraction (Qs/Qt) CaO2, CcvO2, and CcO2 were calculated accordingly. Results showed that Qs/Qt greatly decreased from 0 to 120 min in all the groups (dorsal: 69.3% to 27.3%; left lateral: 59.1% to 25.0%; right lateral: 67.2% to 32.4%). CaO2, CcvO2 and CcO2 improved over time points, with no difference among treatments. PaO2 and PAO2 showed higher values for 60 and 120 min compared to the 0 min value in all groups, with no differences among treatments as well. PaCO2 and ETCO2 in the lateral groups were higher than those in the dorsal group at 120 min. Pressure-controlled ventilation improved gas exchanges in sheep, thereby reducing pulmonary shunt. Recumbency did not interfere with pulmonary shunt, nevertheless, special attention must be paid to lateral recumbency.

Estimating the best fraction of inspired oxygen for calculation of PaO2/FiO2 ratio in acute respiratory distress syndrome due to COVID-19 pneumonia.

Background:The ratio of partial pressure of oxygen in arterial blood (PaO2) to the fraction of inspiratory oxygen concentration (FiO2) is an indicator of pulmonary shunt fraction. PaO2/FiO2 (P/F) ratio is used to classify severity of acute respiratory distress syndrome (ARDS). With the same shunt fraction, P/F ratio decreases with increases in FiO2 which may lead to errors in classifying severity of ARDS. The effect of FiO2 on P/F ratio has not been investigated in COVID-19 pneumonia. In this study, we estimated the best FiO2 for the calculation of P/F ratio in a sample of patients with ARDS due to COVID-19 pneumonia.Materials and Methods:Blood gas and ventilatory data of 108 COVID-19 ARDS patients were analyzed in a cross-sectional observational study. Using Oxygen Status Algorithm the calculated shunt fraction served a basis for calculating P/F ratio for different FiO2. The severity of ARDS determined by P/F ratios at each FiO2s was compared with the shunt-based severity to find the optimum FiO2 for calculation of P/F ratio so the resulting classification has the best match with the reference classification.Results:A FiO2 of 1.0 for calculation of P/F ratio and ARDS classification showed the best match with shunt-based ARDS classification. A regression model was obtained with the PaO2, patient's original FiO2, Hemoglobin concentration, and SaO2 as the independent predictors of the P/F ratio for the FiO2 of 1.0.Conclusion:This study shows a FiO2 of 1.0 as the best value for correct calculation of P/F ratio and proper classification of ARDS.

Hydrogen inhalation in rehabilitation program of the medical staff recovered from COVID-19

Active hydrogen inhalation (H(H2O)m) has powerful antioxidant and antiapoptotic effects. In recent years, it has been used in a number of experimental and clinical studies.Aim. To study the safety and effectiveness of inhalation of the “active form of hydrogen” (AFV;(H(H2O)m)) in the rehabilitation program of coronavirus disease 2019 (COVID-19) survivors during the recovery period.Material and methods. This randomized controlled parallel prospective study included 60 COVID-19 survivors with post-COVID-19 syndrome (ICD-10: U09.9) during the recovery period, with clinical manifestations of chronic fatigue syndrome (CFS), who received standard therapy in accordance with the management protocol of patients with CFS (ICD-10: G93.3): physiotherapy and medication therapy with drugs containing magnesium, B vitamins and L-carnitine. The patients were divided into 2 groups. The experimental group (n=30) included patients who received hydrogen inhalation for 90 minutes every day during 10 days (SUISONIA hydrogen inhalation device, Japan). The control group (n=30) consisted of patients who received standard therapy. In both groups, patients were comparable in sex and mean age: in the experimental group — 53 (22; 70) years, in the control group — 51 (25; 70) years. Biological markers of systemic inflammation, oxygen transport, lactate metabolism, intrapulmonary shunting, 6-minute walk test, and vascular endothelial function were determined in all patients on the 1st and 10th days of follow-up.Results. In the experimental group, a decrease in following parameters was revealed: stiffness index (SI), from 8,8±1,8 to 6,8±1,5 (p&lt;0,0001); ALT, from 24,0±12,7 to 20,22±10,61 U/L (p&lt;0,001); venous blood lactate, from 2,5±0,8 to 1,5±1,0 mmol/L (p&lt;0,001); capillary blood lactate, from 2,9±0,8 to 2,0±0,8 mmol/L (p&lt;0,0001); estimated pulmonary shunt fraction (Qs/Qt, Berggren equation, 1942) from 8,98±5,7 to 5,34±3,2 (p&lt;0,01); white blood cells, from 6,64±1,57 to 5,92±1,32 109/L. In addition, we revealed an increase in the refractive index (RI) from 46,67±13,26% to 63,32±13,44% (p&lt;0,0001), minimum blood oxygen saturation (SpO2) from 92,25±2,9 to 94,25±1, 56% (p&lt;0,05), direct bilirubin from 2,99±1,41 to 3,39±1,34 pmol/L (p&lt;0,01), partial oxygen tension (PvO2) from 26,9±5,0 to 34,8±5,6 mm Hg (p&lt;0,0001), venous oxygen saturation (SvO2) from 51,8±020,6 to 61,1±018,1% (p&lt;0,05), partial capillary oxygen tension (PcO2) from 48,7±15,4 to 63,8±21,2 mm Hg (p&lt;0,01), capillary oxygen saturation (ScO2) from 82,2±4,2 to 86,2±4,8% (p&lt;0,01), distance in 6 minute walk test from 429±45,0 to 569±60 m.Conclusion. Inhalation therapy with H(H2O)m in the rehabilitation program of COVID-19 survivors during the recovery period is a safe and highly effective method. Manifestations of silent hypoxemia and endothelial dysfunction decreased, while exercise tolerance increased. As for laboratory tests, a decrease in the white blood cell count, estimated pulmonary shunt fraction and lactate content parameters was revealed.

Assessment of indicators of pulmonary volemia and systemic inflammatory response in patients with comorbidity of chronic obstructive pulmonary disease and ischemic heart disease after coronary artery bypass grafting

Inroduction. Systemic inflammatory response (SIR) is an obligatory manifestation of operational stress affecting the functional status of patients, which is important to consider in persons with comorbid pathology.Aim. Evaluation of the relationship between pulmonary volemia and SIR indicators in patients with comorbidity of chronic obstructive pulmonary disease (COPD) and ischemic heart disease (IHD) after coronary artery bypass grafting (CABG).Materials and methods. The study included 76 IHD patients aged 53 to 77 years who underwent CABG. Among the surveyed, 2 groups were identified: 39 patients with IHD and 37 – with a combination of IHD and COPD. The following indices were measured by transpulmonary thermodilution: pulmonary blood volume (PBV), extravascular lung water index (EVLWI), pulmonary vascular permeability index (PVPI), pulmonary shunt fraction (Qs/Qt). Determined the concentration in the blood of interleukin 6 and 10 (IL-6, IL-10), tumor necrosis factor-alpha (TNF-α); transforming growth factor-beta1 (TGFβ1), NLR - the ratio of neutrophils to lymphocytes; PLR – the ratio of platelets to lymphocytes.Results. The most pronounced disturbances in the water balance of the lungs, manifested by an increase in EVLWI, PVPI and Qs/Qt were recorded in patients with comorbidity of COPD and IHD immediately after withdrawal from cardiopulmonary bypass. The PBV level at all measurement points in patients with COPD was lower, which indicated the prevalence of right ventricular failure. SIR on operational stress in this category of patients was manifested by the discoordination of the cytokine profile: a sharp increase in the concentration of IL-6 and IL-10 against the background of a relatively stable level of TNFα and TGF-β1, as well as an increase in NLR and PLR.Conclusion. The unidirectional response of pulmonary volemia and SIR indicators to operational stress indicates the pathophysiological relationship of the studied phenomena.

Lungs volume status and oxygen transport in patients with coronary artery disease with various types of comorbidity before and after coronary artery bypass grafting

Aim. Assessment of lung volume status and oxygen transport system in patients with coronary artery disease (CAD) with different clinical types of comorbidity before and after coronary artery bypass grafting (CABG).Material and methods. The observational controlled study included 66 patients with CAD with a median age of 67 years (95% confidence interval [59; 74]), admitted to the Far Eastern Federal University Hospital for elective CABG. Depending on the prevalence of clinical manifestations of comorbidities, CAD patients were ranked into 3 groups of comorbidity: cardiovascular, respiratory and metabolic. The first of them was represented by a combination of CAD and peripheral artery disease, the second — CAD and chronic obstructive pulmonary disease (COPD),the third — CAD and metabolic syndrome. All patients underwent isolated CABG under cardiopulmonary bypass (CPB). Volume and hemodynamic monitoring was carried out by transpulmonary thermodilution using the Pulsion PiCCO Plus (Germany) technology and the following indices: cardiac function index (CFI), extravascular lung water (EVLW), pulmonary vascular permeability index (PVPI). Pulmonary blood volume and oxygen transport indices were determined: oxygen delivery (DO2I) and consumption (VO2I) indices, oxygen-utilization coefficient, and pulmonary shunt fraction (Qs/Qt). The study was carried out in three stages: before the onset of CABG, after its completion and one day after CABG.Results. The analysis of volume and hemodynamic monitoring data demonstrated the heterogeneity of their changes during CABG and one day after with different comorbidity profile. A more noticeable inhibition of the circulatory component of oxygen transport was revealed in patients with COPD, which was illustrated by the lowest CFI (3,2-3,4 ml/min) in relation to other groups of patients. The imbalance of cardio-respiratory interactions in this cohort after withdrawal from cardiopulmonary bypass was manifested by lower DO2I and VO2I and a maximum increase in Qs/Qt, exceeding 1,6 times the comparison groups. The respiratory and metabolic comorbidity of CAD was characterized by a significantly larger volume of extravascular lung water due to the higher permeability of the pulmonary vessels, which was documented by EVLW values, which exceeded the upper reference limit by 1,8-2 times and an increase in PVPI. In patients with cardiovascular comorbidity, lung volume violation was less noticeable.Conclusion. A comprehensive analysis of lung volume status and oxygen transport makes it possible to more accurately assess the functional status of patients with CAD, to increase the effectiveness of risk stratification and to prevent possible complications during CABG and in the early postoperative period.

Arterial oxygenation in anesthetized horses placed in a 5-degree reverse Trendelenburg position

Low arterial oxygen is a common complication in anesthetized horses and placing the animal in reverse Trendelenburg (RT) position may treat hypoxemia. The objective of this study was to assess the arterial partial pressure of oxygen (PaO2) in horses placed in a 5-degree RT compared to horizontal (H) position. Client-owned healthy horses (n = 60) undergoing elective surgeries were enrolled in a randomized controlled clinical study. Horses were sedated with butorphanol, an α2-adrenoceptor agonist, ± acepromazine and induced with ketamine combined with a benzodiazepine, propofol, or guaifenesin. Anesthesia was maintained with isoflurane in oxygen with mechanical ventilation. Each group (RT and H) included 30 horses, 10 in each recumbency (dorsal, right and left lateral). Arterial blood gas analyses (aBG) were performed following arterial catheter placement then hourly. Time first-to-last aBG, changes in PaO2, dynamic compliance (Cdyn), estimated pulmonary shunt fraction (F-shunt), and alveolar dead space to tidal volume ratio (VD/VT) were evaluated with a 2-way analysis of variance. Statistical significance was set at p < .05. Overall, PaO2 increased in all groups; however no significant difference was found between recumbencies (dorsal, right and left lateral) and RT versus H in changes over time for PaO2 (p = .064 and p = .070, respectively), Cdyn (p = .721 and p = .672, respectively), F-shunt (p = .055 and p = .054, respectively), or VD/VT (p = .616 and p = .064, respectively). In healthy anesthetized horses, 5-degree RT did not affect changes in PaO2 as compared to H position.

99MTC-MAA HEPATIC PERFUSION IMAGING PRIOR TO 90Y RADIOEMBOLIZATION: HOW THORACIC UPTAKE CHANGES MANAGEMENT

SESSION TITLE: Medical Student/Resident Imaging Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Targeted radioembolization with 90Y (yttrium 90) has shown a survival advantage in advanced stage hepatocellular carcinoma1. Interventional radiologists perform this procedure, however nuclear, thoracic, and abdominal imagers play a key role in determining candidacy for this treatment via interpretation of 99mTc-MAA (macroaggregated albumin) hepatic perfusion imaging and accompanying CT scans2. It is critical for pulmonologists and thoracic radiologists to recognize normal and abnormal studies to avoid potential deadly complications in patients who are poor candidates for this therapy. CASE PRESENTATION: The patient is a 70-year-old male who presented with abdominal pain and was found to have multiple hepatic masses and bile duct dilation, which on biopsy was consistent with aggressive multifocal hepatocellular carcinoma. Additionally, he was found to have a partial portal vein thrombosis. Because of the extent of the disease he was deemed not to be a surgical candidate and therefore was referred for evaluation for potential 90Y chemoembolization. To evaluate candidacy, the patient underwent 99mTc-MAA hepatic perfusion imaging with chest and abdominopelvic CT scans. Results are shown in Figure 1. Scintigraphy demonstrated a pulmonary shunt fraction of 80%. DISCUSSION: It is essential to recognize that these results are highly abnormal and an absolute contraindication to 90Y chemoembolization. 90Y undergoes B-decay which can result in radiation pneumonitis when spheres containing the radiopharmaceutical lodge in the pulmonary capillaries. For 90Y sphere embolization, <10% lung shunting is considered acceptable for therapy. For patients with shunt fractions <10-20%, a reduction of spheres delivered is necessary, and shunts >20% are a contraindication to the procedure3. Notably, portal vein thrombosis is not a contraindication however should be considered in planning. CT and angiography are key tools for identifying the shunt. CONCLUSIONS: 90Y embolization may be a helpful tool to attenuate the progression of hepatocellular carcinoma, but carries the risk of dangerous radiation pneumonitis in patients with significant pulmonary shunts. It is essential for clinicians to be aware of the potential danger and able to recognize abnormalities on preprocedural imaging studies to prevent harming the patient. Reference #1: Jordi Bruix, Margarita Sala, Josep M. Llovet. Chemoembolization for hepatocellular carcinoma. Gastroenterology; Volume 127, Issue 5, Supplement 1, 2004, S179-S188, https://doi.org/10.1053/j.gastro.2004.09.032. Reference #2: Kao, Y., Steinberg, J.D., Tay, Y. et al. Post-radioembolization yttrium-90 PET/CT - part 1: diagnostic reporting. EJNMMI Res 3, 56 (2013). https://doi.org/10.1186/2191-219X-3-56. Reference #3: Livnat Uliel, Henry D. Royal, Michael D. Darcy, Darryl A. Zuckerman, Akash Sharma and Nael E. Saad. From the Angio Suite to the γ-Camera: Vascular Mapping and 99mTc-MAA Hepatic Perfusion Imaging Before Liver Radioembolization—A Comprehensive Pictorial Review. J Nucl Med November 1, 2012 vol. 53 no. 11 1736-1747. doi: 10.2967/jnumed.112.105361. DISCLOSURES: No relevant relationships by Kathleen Capaccione, source=Web Response Speaker/Speaker's Bureau relationship with Genentech Please note: $20001 - $100000 Added 06/11/2020 by Mary Salvatore, source=Web Response, value=Honoraria research grant relationship with Boehringer Ingelheim Please note: >$100000 Added 06/11/2020 by Mary Salvatore, source=Web Response, value=Grant/Research Support

Red Bull Increases Heart Rate at Near Sea Level and Pulmonary Shunt Fraction at High Altitude in a Porcine Model.

Red Bull energy drink is popular among athletes, students and drivers for stimulating effects or enhancing physical performance. In previous work, Red Bull has been shown to exert manifold cardiovascular effects at rest and during exercise. Red Bull with caffeine as the main ingredient increases blood pressure in resting individuals, probably due to an increased release of (nor)-epinephrine. Red Bull has been shown to alter heart rate or leaving it unchanged. Little is known about possible effects of caffeinated energy drinks on pulmonary ventilation/perfusion distribution at sea level or at altitude. Here, we hypothesized a possible alteration of pulmonary blood flow in ambient air and in hypoxia after Red Bull consumption. We subjected eight anesthetized piglets in normoxia (FiO2 = 0.21) and in hypoxia (FiO2 = 0.13), respectively, to 10 mL/kg Red Bull ingestion. Another eight animals served as controls receiving an equivalent amount of saline. In addition to cardiovascular data, ventilation/perfusion distribution of the lung was assessed by using the multiple inert gas elimination technique (MIGET). Heart rate increased in normoxic conditions but was not different from controls in acute short-term hypoxia after oral Red Bull ingestion in piglets. For the first time, we demonstrate an increased fraction of pulmonary shunt with unchanged distribution of pulmonary blood flow after Red Bull administration in acute short-term hypoxia. In summary, these findings do not oppose moderate consumption of caffeinated energy drinks even at altitude at rest and during exercise.

Nebulized dexmedetomidine improves pulmonary shunt and lung mechanics during one-lung ventilation: a randomized clinical controlled trial.

BackgroundDexmedetomidine (Dex), a selective a2-adrenergic receptor agonist, has been previously reported to attenuate intrapulmonary shunt during one-lung ventilation (OLV) and to alleviate bronchoconstriction. However, the therapeutic effects of nebulized Dex on pulmonary shunt and lung mechanics during OLV have not been evaluated. Here we determine whether nebulized dexmedetomidine improved pulmonary shunt and lung mechanics in patients undergoing elective thoracic surgery in a prospective randomized controlled clinical trial.MethodsOne hundred and twenty-eight patients undergoing elective thoracoscopic surgery were included in this study and randomly divided into four groups: 0.9% saline (Placebo group), 0.5 µg/kg (Dex0.5 group), 1 µg/kg (Dex1 group) and 2 µg/kg (Dex2group) dexmedetomidine. After bronchial intubation, patients received different nebulized doses of dexmedetomidine (0.5 µg/kg, 1 µg/kg and 2 µg/kg) or 0.9% saline placebo during two-lung ventilation(TLV). OLV was initiated 15 min after bronchial intubation. Anesthesia was maintained with intravenous infusion of cisatracurium and propofol. Bispectral Index values were maintained within 40–50 by adjusting the infusion of propofol in all groups. Arterial blood gas samples and central venous blood gas samples were taken as follows: 15 min after bronchial intubation during two-lung ventilation (TLV15), after 30 and 60 min of OLV (OLV30and OLV60, respectively) and 15 min after reinstitution of TLV (ReTLV). Dynamic compliance was also calculated at TLV15, OLV30, OLV60 and ReTLV.ResultsDex decreased the requirement of propofol in a dose-dependent manner(P = 0.000). Heart rate (HR) and mean arterial pressure (MAP) displayed no significant difference among groups (P = 0.397 and 0.863). Compared with the placebo group, Dex administered between 0.5 and 2 µg/kg increased partial pressure of oxygen (PaO2) significantly at OLV30 and OLV60(P = 0.000); however, Dex administered between 1 and 2 µg/kg decreased pulmonary shunt fraction (Qs/Qt) at OLV30 and OLV60(P = 0.000). Compared with the placebo group, there were significant increases with dynamic compliance (Cdyn) after OLV in Dex0.5, Dex1 and Dex2group(P = 0.000). Conclusions. Nebulized dexmedetomidine improved oxygenation not only by decreasing pulmonary shunt but also by improving lung compliance during OLV, which may be effective in managing OLV.