Objective To investigate whether the new oxygenation index [ PaO2 /( FiO2 ×Paw ) ]which including mean airway pressure ( Paw ) for assessing intrapulmonary shunting of acute respiratory distress syndrome( ARDS) could be more accurate than the conventional oxygenation ratio ( PaO2 /FiO2 ) .Methods Twelve patients with ARDS were recruited. All patients received mechanical ventilation under lung ventilation protective strategy ( VT 6 mL/kg, f 16 bpm, FiO2 60% ) , and had a Swan-Ganz catheter inserted. Then, pressure/ volume curves were determined by low-flow method and the lower inflection point pressure was surveyed. Subsequently, parameters of respiratory mechanics and haemodynamics were recorded while periphery and pulmonary artery blood gas analysis were performed when positive end expiratory pressure ( PEEP) were changed. PaO2 /FiO2 and Qsp/Qt were calculated through special formula respectively. Results The progressive PEEP could not change Cst, PaO2 /FiO2 , and PaO2 / ( FiO2 ×Paw) in patients with ARDS significantly ( P gt; 0. 05) . The progressive PEEP did not change Qsp/Qt significantly ( P gt;0. 05) . The Δz which was used to test the difference between the correlation coefficient of Qsp/Qt and PaO2 / ( FiO2 ×Paw) and the correlation coefficient of Qsp/Qt and PaO2 /FiO2 was 0. 571, and there was no difference between the two correlation coefficients ( P gt; 0. 05) . It was not Paw but Cst which impacted on Qsp/Qt and PaO2 /FiO2 . Conclusion PaO2 / ( FiO2 × Paw ) is equal to PaO2 /FiO2 in assessing intrapulmonary shunting of ARDS.
【摘要】 目的 通过观察单肺通气患者术中氧合指数（oxygenation index，OI）、呼吸指数（respiratory index，RI）及动态肺顺应性（dynamic lung compliance，Cdyn）的变化，探讨高渗氯化钠溶液对术中单肺通气患者的肺保护作用。 方法 选择2009年12月-2011年2月完成的美国麻醉师协会分级为Ⅰ~Ⅲ级，心肺功能筛查、血常规、肝肾功能及凝血功能无明显异常，拟在全麻双腔气管插管下行开胸手术，术中需行单肺通气患者60例，随机分为高渗氯化钠组（A组）和对照组（B组），每组30例。A组在开始单肺通气后30 min快速输注7.5%高渗氯化钠溶液2 mL/kg，15 min内输注完毕，B组输注等量生理盐水，分别记录输注前（T1）、输注完毕时（T2）、输注后30 min（T3）、输注后1 h（T4）的OI、RI及Cdyn变化，并比较两组各时间点生命体征变化。 结果 两组患者OI、RI及Cdyn在T1、T2时差异无统计学意义（Pgt;0.05）；两组患者不同时间点平均动脉压、心率、脉搏血氧饱和度、中心静脉压、呼气末CO2分压比较差异无统计学意义（Pgt;0.05）；A组患者在T3、T4时的OI和Cdyn较B组明显升高，RI明显降低（Plt;0.05）；且A组患者在T3、T4时的OI和Cdyn较T1时明显增高，RI明显降低（Plt;0.05）。 结论 高渗氯化钠溶液能改善术中单肺通气患者的OI、RI及Cdyn，对肺功能有一定的保护作用。【Abstract】 Objective To observe the oxygenation index (OI), respiratory index (RI) and dynamic lung compliance (Cdyn) changes of the patients with one-lung ventilation, in order to determine if hypertonic saline has lung protective effects. Methods Sixty ASA Ⅰ-Ⅲ patients who needed one-lung ventilation during thoracotomy under general anesthesia with double-lunmen endotracheal tubes were chosen to be the study subjects. No obvious abnormalities were detected by cardiopulmonary function screening, blood test, hepatorenal function and blood coagulation examinations in these patients. They were randomly divided into hypertonic saline group (group A) and control group (group B) with 30 patients in each group. For patients in group A, 30 minutes after one-lung ventilation, infusion of 7.5% hypertonic saline solution at 2 mL/kg was carried out and completed in 15 minutes. For patients in group B, the same amount of saline solution was infused. We recorded OI, RI and Cdyn changes before the infusion (T1), on the completion of the infusion (T2), 30 minutes after the infusion (T3), and 1 hour after the infusion (T4). The changes of vital signs in patients of the two groups were compared. Results OI, RI and Cdyn were not significant different between the two groups at T1 and T2 (Pgt;0.05). Mean arterial pressure (MAP), heart rate (HR), SpO2, central venous pressure (CVP), and PetCO2 were not significant different between the two groups at all time points (Pgt;0.05). OI and Cdyn of group A patients were significantly higher than those of group B, while RI was significantly lower at T3 and T4 (Plt;0.05). Cdyn and OI of group A patients at T3 and T4 were significantly higher when compared with T1, and RI was significantly lower (Plt;0.05). Conclusion Hypertonic saline has the lung protection effect in patients with one-lung ventilation by improving OI, RI and Cdyn.
Objective To investigate the effect of low-flow inhaling NO for short time on postoperative cardiac and pulmonary functions in infants with congenital ventricular septal defect complicated with severe pulmonary hypertension. Methods Forty-five patients with congenital ventricular septal defect complicated with severe pulmonary hypertension from May 2014 to May 2016 in our hospital were enrolled. There were 19 males and 26 females, whose age ranged from 1 to 22 months (average age: 7.2±14.4 months) and weight ranged from 2.7 to 10.5 kg (average weight: 6.8±3.6 kg). The patients were randomly divided into three groups (n=15 in each): the blank group, the prior inhalation group and the posterior inhalation group. The blank group did not inhale NO, and the prior inhalation group inhalated NO for 10 min after tracheal and intubation. After the opening of the aorta, the posterior inhalation group inhaled NO for 10 min. The concentration of NO was 20 × 10–6. The pressure ratio of pulmonary circulation/systematic circulation, heart index and oxygenation index were calculated and the troponin value of the three groups was monitored 10 min after returning to intensive care unit (ICU) and postoperatively 1 h, 3 h and 24 h. Differences among above indicators between three groups were compared. Results The troponin value of the posterior inhalation group within 3 h increased most, followed by the blank group and the prior inhalation group. Postoperatively 1 h and 3 h, the troponin value of the prior inhalation group was significantly less than that of the blank group and posterior inhalation group (P<0.01) and the value on postoperative 24 h in each group was lower than that on postoperative 3 h. The cardiac index of prior inhalation group was higher than that of the blank group and the posterior inhalation group at each time point. Postoperatively 3 h and 24 has well as 10 min after returning to ICU, the cardiac index in prior inhalation group was significantly higher than that of the posterior inhalation group (P<0.05). The pressure ratio of pulmonary circulation/systematic circulation of posterior inhalation group increased more than that of blank group; the differences in two groups were significant between postoperative 3 h and 10 min after returning to ICU (P<0.01). There was no statistical significance in the pressure ratio on postoperative 24 h and 10 min after returning to ICU (P>0.05) in three groups. The index of oxygenation of the prior inhalation group was higher than that of the blank group and the posterior inhalation group and statistically different from that of posterior inhalation group (P<0.05). Conclusion Inhaling NO 10 min preoperatively can reduce the injury to the heart and lung function effectively, but the result is the opposite when inhalating NO 10 min after aorta opening.
ObjectiveTo evaluate the effect of driving pressure-guided lung protective ventilation strategy on lung function in adult patients under elective cardiac surgery with cardiopulmonary bypass.MethodsIn this randomized controlled trial, 106 patients scheduled for elective valve surgery via median sternal incision under cardiopulmonary bypass from July to October 2020 at West China Hospital of Sichuan University were included in final analysis. Patients were divided into two groups randomly. Both groups received volume-controlled ventilation. A protective ventilation group (a control group, n=53) underwent traditional lung protective ventilation strategy with positive end-expiratory pressure (PEEP) of 5 cm H2O and received conventional protective ventilation with tidal volume of 7 mL/kg of predicted body weight and PEEP of 5 cm H2O, and recruitment maneuver. An individualized PEEP group (a driving pressure group, n=53) received the same tidal volume and recruitment, but with individualized PEEP which produced the lowest driving pressure. The primary outcome was oxygen index (OI) after ICU admission in 30 minutes, and the secondary outcomes were the incidence of OI below 300 mm Hg, the severity of OI descending scale (the Berlin definition), the incidence of pulmonary complications at 7 days after surgery and surgeons’ satisfaction on ventilation.ResultsThere was a statistical difference in OI after ICU admission in 30 minutes between the two groups (273.5±75.5 mm Hg vs. 358.0±65.3 mm Hg, P=0.00). The driving pressure group had lower incidence of postoperative OI<300 mm Hg (16.9% vs. 49.0%, OR=0.21, 95%CI 0.08-0.52, P=0.00) and less severity of OI classification than the control group (P=0.00). The incidence of pulmonary complications at 7 days after surgery was comparable between the driving pressure group and the control group (28.3% vs. 33.9%, OR=0.76, 95%CI 0.33-1.75, P=0.48). The atelectasis rate was lower in the driving pressure group (1.0% vs. 15.0%, OR=0.10, 95%CI 0.01-0.89, P=0.01).ConclusionApplication of driving pressure-guided ventilation is associated with a higher OI and less lung injury after ICU admission compared with the conventional protective ventilation in patients having valve surgery.
ObjectiveTo investigate the independent risk factors associated with postoperative acute respiratory distress syndrome in patients undergoing type A aortic dissection surgery.MethodsThe clinical data of 147 patients who underwent acute type A aortic dissection surgery in the First Affiliated Hospital of Anhui Medical University from 2015 to 2019 were retrospectively analyzed. There were 110 males at age of 51.9±10.1 years and 37 females at age of 54.3±11.1 years. According to whether the patients developed ARDS after surgery, all of the patients were divided into a ARDS group or a non-ARDS group. Logistic regress analysis was utilized to establish the predictive mode to identify the independent risk factors related to ARDS.ResultsOf the patients, 25 developed postoperative ARDS. Among them, 5 patients were mild ARDS, 13 patients were moderate, and 7 patients were severe ARDS. Multivariate logistic regression analysis showed that deep hypothermic circulatory arrest time [odds ratio (OR)=1.067, 95% confidence interval (CI) 1.014-1.124, P=0.013], cardiopulmonary bypass time (OR=1.012, 95%CI 1.001-1.022, P=0.027) and perioperative plasma input (OR=1.001, 95%CI 1.000-1.002, P=0.011) were independently associated with ARDS in patients undergoing acute A aortic dissection surgery. Receiver operating characteristic (ROC) curve analysis demonstrated a good discrimination ability of the logistic regression model, with an area under the curve of 0.835 (95%CI 0.740-0.929, P=0.000).ConclusionDuration of deep hypothermic circulatory arrest, cardiopulmonary bypass time and perioperative plasma are independent risk factors for postoperative ARDS in patients undergoing type A aortic dissection surgery.