ONE-LUNG VENTILATION PATIENTS: CLINICAL CONTEXT OF ADMINISTRATION OF DIFFERENT DOSES OF DEXMEDETOMIDINE

Background: To investigate the effects of different doses of dexmedetomidine on inflammatory response, oxidative stress, cerebral tissue oxygen saturation (SctO2) and intrapulmonary shunt in patients undergoing one-lung ventilation (OLV). Methods: Sixty patients undergoing open pulmonary lobectomy in our hospital from January 2016 to December 2017 were enrolled and randomly divided into high-dose dexmedetomidine group (group D1, 1 μg/kg, n=20), low-dose dexmedetomidine group (group D2, 0.5 μg/kg, n=20) and control group (group C, n=20). Then, arterial blood and internal jugular venous blood were taken before anesthesia induction (T0) and at 15 min after two-lung ventilation (T1) and 5 min (T2) and 30 min (T3) after OLV for later use. Next, the changes in hemodynamic parameters [mean arterial pressure (MAP), heart rate (HR) and pulse oxygen saturation (SpO2)] of patients were observed in each group. Enzyme-linked immunosorbent assay (ELISA) was carried out to detect serum inflammatory factors such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) and oxidative stress indicators [superoxide dismutase (SOD) and malondialdehyde (MDA)]. The changes in SctO2, arterial partial pressure of oxygen (PaO2) and intrapulmonary shunt Qs/Qt were observed. Additionally, the changes in lung function indicators like lung dynamic compliance (Cdyn) and airway peak pressure (Ppeak) were determined. Results: There were no statistically significant differences in the MAP, HR and SpO2 among three groups at each observation time point (P>0.05). At T2 and T3, the levels of serum IL-6, TNF-α and IL-8 were obviously decreased in group D1 and D2 compared with those in group C (P<0.05), and the decreases in group D1 were overtly larger than those in group D2, and the decreases at T3 were markedly greater than those at T2 (P<0.05). In comparison with group C, group D1 and D2 had notably reduced levels of serum reactive oxygen species (ROS) and MDA (P<0.05) and remarkably increased SOD content (P<0.05) at T2 and T3, and the effects were markedly better in group D1 than those in group D2. Besides, they were significantly superior at T3 to those at T2 (P<0.05). The SctO2 in group D1 and D2 was evidently lowered at T2 and T3 compared with that at T0, and the decrease in group D1 was distinctly smaller than that in group D2 (P<0.05). The Qs/Qt was significantly lower in group D1 and D2 than that in group C at T2 and T3 (P<0.05), while the PaO2 content was notably raised (P<0.05), and the decrease and increase were significantly larger in group D1 than those in group D2, and they were obviously greater at T3 to those at T2 (P<0.05). At T0 and T1, no significant differences were detected in the Cdyn, Pplat and Ppeak among three groups. At T2 and T3, the Cdyn was significantly elevated, while the Pplat and Ppeak overtly declined (P<0.05), and group D1 had greater changes in comparison with group D2, and the changes were obviously more evident at T3 to those at T2 (P<0.05). Conclusions: Dexmedetomidine effectively ameliorates inflammatory response and oxidative stress, lowers oxygenation, Qs/Qt and the decrease in SctO2 and improves lung function during OLV, with good efficacy.

Usefulness of Lung Ultrasound for early detection of Hospital-Acquired Pneumonia in Patients on Veno-Arterial Extra Corporeal Membrane Oxygenation.

BACKGROUND: Hospital-Acquired Pneumonia (HAP) is the most common and severe complication in patients treated with veno-arterial extracorporeal membrane oxygenation (ECMO). HAP early detection is challenging but crucial for improving clinical outcomes. We conduct an observational study to assess whether Lung Ultrasound (LUS) improves detection of HAP in in patients treated with veno-arterial ECMO.METHODS: We conducted a single-center, prospective, observational study including adult patients receiving veno-arterial extracorporeal membrane oxygenation assistance that presented acute respiratory failure. Bedside LUS and chest radiography were performed at the time of inclusion when HAP was suspected. Then the patients were independently assessed for HAP including microbiological evidence. The sonographic features of HAP on veno-arterial ECMO were determined. We then compared the performance of the lung ultrasound simplified clinical pulmonary score (LUS-sCPIS), including bio-clinical data and the Doppler detection of intrapulmonary shunt, to the sCPIS, including bio-clinical and chest radiological data for detection of HAP. RESULTS: We included 70 patients, of which 44 (63%) were independently diagnosed with hospital-acquired pneumonia. LUS examination revealed that Doppler intrapulmonary shunt (P=0.0000043) and dynamic air bronchogram (P=0.00024) were the most frequent hospital-acquired pneumonia-related signs. The LUS-sCPIS (Area under the curve = 0.77) yielded significantly better results than the sCPIS (Area under the curve = 0.65; P = 0.004), while leukocyte count, temperature and chest radiology were not discriminating for the hospital-acquired pneumonia diagnosis.CONCLUSION: The diagnosis of hospital-acquired pneumonia is a daily challenge for the clinician managing patients on veno-arterial ECMO . Lung ultrasound is more powerful than chest radiography and can be a valuable aid as initial imaging modality for the diagnosis of pneumonia. Intrapulmonary shunt detected using color Doppler and dynamic air bronchogram appear to be particularly discriminating for the diagnosis of hospital-acquired pneumonia.CLINICAL TRIAL REGSITRATION: NA

Patent foramen ovale revealed by COVID-19 pneumonia

Background Platypnea-orthodeoxia syndrome (POS) is a rare condition characterized by dyspnoea (platypnea) and arterial desaturation in the upright position resolved in the supine position (orthodeoxia). Intracardiac shunt, pulmonary ventilation–perfusion mismatch and others intrapulmonary abnormalities are involved. Case presentation We report a case of POS associated with two pathophysiological issues: one, cardiac POS caused by a patent foramen ovale (PFO) and second, pulmonary POS due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) interstitial pneumonia. POS has resolved after recovery of coronavirus disease 2019 (COVID-19) pneumonia. Conclusions Right-to-left interatrial shunt and intrapulmonary shunt caused by SARS-CoV-2 pneumonia contributed to refractory hypoxemia and POS. Therefore, in case of COVID-19 patient with unexplained POS, the existence of PFO must be investigated.

Right and Left-sided Valve Disease: A Case of Subclinical Intrapulmonary Shunt in an Adult with Malignant Carcinoid

Carcinoid tumors are highly differentiated neuroendocrine tumors (NET) that most commonly originate from the gastrointestinal tract. Liver metastases bypass first-pass metabolism and liberate vasoactive hormones into systemic circulation, causing flushing and diarrhea. Prolonged levels of circulating serotonin may adversely affect the heart by creating fibrotic endocardial deposits on native valves. The remaining serotonin is metabolized in the pulmonary circuit that leads to pathognomonic valvular disease isolated to the right side of the heart. We present a case of an adult male with known carcinoid syndrome who presented with involvement of right, as well as left-sided valves. He was found to have an intrapulmonary shunt on transesophageal echocardiogram (TEE) with bubble study. Intrapulmonary shunt should be considered, in conjunction with right-to-left shunt, lung involvement, and high levels of serotonin, for carcinoid patients with right and left-sided valve disease.

Benefit of Physiologically Variable Over Pressure-Controlled Ventilation in a Model of Chronic Obstructive Pulmonary Disease: A Randomized Study

IntroductionThe advantages of physiologically variable ventilation (PVV) based on a spontaneous breathing pattern have been demonstrated in several respiratory conditions. However, its potential benefits in chronic obstructive pulmonary disease (COPD) have not yet been characterized. We used an experimental model of COPD to compare respiratory function outcomes after 6 h of PVV versus conventional pressure-controlled ventilation (PCV).Materials and MethodsRabbits received nebulized elastase and lipopolysaccharide throughout 4 weeks. After 30 days, animals were anesthetized, tracheotomized, and randomized to receive 6 h of physiologically variable (n = 8) or conventional PCV (n = 7). Blood gases, respiratory mechanics, and chest fluoroscopy were assessed hourly.ResultsAfter 6 h of ventilation, animals receiving variable ventilation demonstrated significantly higher oxygenation index (PaO2/FiO2 441 ± 37 (mean ± standard deviation) versus 354 ± 61 mmHg, p &lt; 0.001) and lower respiratory elastance (359 ± 36 versus 463 ± 81 cmH2O/L, p &lt; 0.01) than animals receiving PCV. Animals ventilated with the variable mode also presented less lung derecruitment (decrease in lung aerated area, –3.4 ± 9.9 versus –17.9 ± 6.7%, p &lt; 0.01) and intrapulmonary shunt fraction (9.6 ± 4.1 versus 17.0 ± 5.8%, p &lt; 0.01).ConclusionPVV applied to a model of COPD improved oxygenation, respiratory mechanics, lung aeration, and intrapulmonary shunt fraction compared to conventional ventilation. A reduction in alveolar derecruitment and lung tissue stress leading to better aeration and gas exchange may explain the benefits of PVV.