Since December 2019, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection has gradually spread all over the world. With the implementation of class B infectious disease management policy for coronavirus disease 2019 (COVID-19), China has experienced a pandemic. For patients receiving a time-sensitive or emergency surgery, SARS-CoV-2 infection may increase the risk of postoperative pulmonary complications. An appropriate perioperative mechanical ventilation strategy, such as lung protective ventilation strategy, is particularly important for preventing postoperative pulmonary complications in patients undergoing general anesthesia. In addition, how to protect medical personnel from being infected is also the focus we need to pay attention to. This article will discuss the perioperative mechanical ventilation strategy for COVID-19 patients and the protection of medical personnel, in order to provide reference for the development of guidelines.
摘要:目的: 评价机械通气对胸腔内脉搏氧饱和度的影响。 方法 :以食道、气管和降主动脉作为胸腔内脉搏氧饱和度的监测位点,将改制后的氧饱和度探头分别固定于上述部位,并连接于同一监护仪上。纯氧通气,待上述氧饱和度容积波波形和读数稳定,停止机械通气30s。以录像的方式记录机械通气停止前后30 s内食道、气管和降主动脉SpO2容积波和读数的变化。同时记录舌SpO2。 结果 :机械通气时,食道、气管和降主动脉三个监测位点均可获得异常高大的SpO2容积波;停止通气时,异常高大的氧饱和度波形消失。食道、气管和降主动脉脉搏容积波变异率分别为112%,74%,302%。降主动脉脉搏容积波的变异率明显高于食道和气管( 〖WTBX〗P ＜005)。机械通气停止前后30s内食道、气管和降主动脉的SpO2读数变化无显著差异(〖WTBX〗P ＞005)。 结论 :机械通气对胸腔内食道、气管和降主动脉氧饱和度读数无影响,主要影响是脉搏容积波。且各位点间脉搏氧容积波受呼吸的影响不同。Abstract: Objective: To investigate the impact of mechanical ventilation on pulse oximetry in thoracic cavity. Methods : After dogs anesthesia induction and thoracotomy, pulse oximeters were simultaneously placed at esophagus, trachea, and descending aorta, and connected with the same monitor for SpO2 monitoring. During ventilation with 100% oxygen, the mechanical ventilator was temporarily switched off for 30 seconds after high quality PPG waveforms and SpO2 readings were obtained. SpO2 signals and readings from esophagus (SeO2), trachea (StraO2), descending aorta (SDAO2) shown on the monitoring screen were recorded by the SONY video before and after stopventilation. And StonO2 were also recorded. Results : Abnormally largeamplitude PPG waves were found in normal waves at monitoring sites of esophagus, trachea, and descending aorta in all animals during ventilation; however, they disappeared without ventilator. The variation rate in ventilationinduced PPG amplitude were 112%, 74%, 302% at esophagus, trachea and descending aorta respectively. The PPG amplitude variation rate from SDAO2 was higher than that from SeO2 and StraO2 (〖WTBX〗P ＜005). However, the SpO2 readings obtained from pulse oximetries in all sites were no significantly statistical difference within 30s before and after temporarily stopventilation (〖WTBX〗P ＞005). Conclusion : Abnormally amplitude PPG waveforms from oximetry probe placed at esophagus, trachea, and descending aorta were induced by ventilation. The Variation rate in ventilationinduced PPG amplitude was various at different monitoring sites. The SpO2 readings from esophagus, trachea, and descending aorta were not significantly contaminated by ventilation.
对意外或自主拔管患者的研究显示，接受完全机械通气患者的23％和开始撤机过程患者的69％并不需要重新插管，这表明机械通气患者的撤机存在被延迟的倾向，致使患者承受不必要的痛苦，增加了并发症的发生率和医疗费用。撤机过程所耗费的时间占机械通气整个时间的40％~50％ 。Esteban等的研究证明：延长通气时间增加病死率。在美国，机械通气的费用约2 000美元／d，延长通气者占总机械通气患者的6％，但却消耗ICU资源的37％。我国的撤机现状与之类似，日益增多的撤机困难患者占用各ICU的有限资源，成为医疗费用和床位周转的沉重负担。机械通气撤离的研究亟待加强。
Objective To explore the application value of shear wave elastography (SWE) combined with diaphragmatic thickening fraction (DTF) and rapid shallow breathing index (RSBI) in predicting the results of weaning of patients with mechanical ventilation. Methods Fifty-two patients with severe illness who were hospitalized in this hospital from January 2022 to September 2022 were treated with mechanical ventilation. After meeting the conditions for weaning, they underwent spontaneous breathing test, and the diaphragm function of patients was evaluated by measuring DTF using ultrasound technology and shear modulus (SM) using SWE technology. According to the weaning results, they were divided into weaning success group and weaning failure group, The differences of mechanical ventilation time, acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) score, respiratory rate, RSBI, oxygenation index, DTF, SM and other parameters between the two groups were compared. Multivariate logistic regression was used to analyze the factors affecting the withdrawal results. The receiver operator characteristic (ROC) curve was used to evaluate the predictive value of potential influencing factors on the withdrawal results. Results There were 39 cases of successful withdrawal and 13 cases of failure. There were significant differences in mechanical ventilation time, respiratory rate, RSBI, DTF and SM between the successful weaning group and the failure group (P<0.05). Through multivariate logistic regression analysis, RSBI [area under the ROC curve (AUC)=0.771, 95% confidence interval (CI) 0.589 - 0.953], DTF (AUC=0.806, 95%CI 0.661 - 0.951), SM (AUC=0.838, 95%CI 0.695 - 0.981) were independent factors that affected the results of withdrawal. The single parameter AUC was smaller than the combined index with RSBI≤70.48 times·min–1L–1, DTF≥30.0%, SM≥10.0 kPa as the cutoff value (AUC=0.937, 95%CI 0.714 - 1.0, diagnostic sensitivity, specificity and accuracy were 94.9%, 84.6% and 92.3% respectively). Conclusions SWE technology provides a new quantitative index for evaluating diaphragm function by evaluating diaphragm stiffness. Diaphragm stiffness combined with DTF and RSBI can better predict the successful withdrawal in patients with mechanical ventilation.
Objective To investigate the predictive value of mechanical power (MP) in the weaning outcome of adaptive mechanical ventilation plus intelligent trigger (AMV+IntelliCycle, simply called AMV) mode for acute respiratory distress syndrome (ARDS) patients. Methods From November 2019 to March 2021, patients with mild to moderate ARDS who were treated with invasive mechanical ventilation in the intensive care unit of the First Affiliated Hospital of Jinzhou Medical University were divided into successful weaning group and failed weaning group according to the outcome of weaning. All patients were treated with AMV mode during the trial. The MP, oral closure pressure (P0.1), respiratory rate (RR) and tidal volume (VT) of the two groups were compared 30 min and 2 h after spontaneous breathing trial (SBT). The correlation between 30 min and 2 h MP and shallow rapid respiratory index (RSBI) was analyzed by Pearson correlation. Receiver operating characteristic (ROC) curve was used to analyze the predictive value of 30 min MP in ARDS patients with AMV mode weaning failure. Results Sixty-eight patients were included in the study, 49 of them were successfully removed and 19 of them failed. There was no statistical significance in age, gender, body mass index, oxygenation index, acute physiology and chronic health evaluation Ⅱ score, reasons for mechanical ventilation (respiratory failure, sepsis, intracranial lesions, and others) between the two groups (all P>0.05). The MP, P0.1 and RR at SBT 30 min and 2 h of the successful weaning group was lower than those of the failed weaning group (all P<0.05), but the VT of the successful weaning group was higher than the failed weaning group (all P<0.05). There was a significant relation between the MP at SBT 30 min and 2 h and RSBI (r value was 0.640 and 0.702 respectively, both P<0.05). The area under ROC curve of MP was 0.674, 95% confidence interval was 0.531 - 0.817, P value was 0.027, sensitivity was 71.73%, specificity was 91.49%, positive predictive value was 0.789, negative predictive value was 0.878, optimal cutoff value was 16.500. The results showed that 30 min MP had a good predictive value for the failure of weaning in AMV mode in ARDS patients. Conclusion MP can be used as an accurate index to predict the outcome of weaning in ARDS patients with AMV mode.
ObjectiveTo assess the effectiveness of phrenic nerve electrical stimulation (PNES) on extubation outcomes in intensive care unit (ICU) patients undergoing mechanical ventilation using a meta-analysis approach. Methods A comprehensive search was conducted on the Cochrane Library, PubMed, Web of Science, Embase, and China National Knowledge Infrastructure (CNKI) for randomized controlled trials (RCTs) published from database inception to December 2023, evaluating the effect of PNES on extubation outcomes in ICU patients receiving mechanical ventilation. The control group received standard rehabilitation measures, while the intervention group received PNES in addition to standard rehabilitation. Two reviewers independently screened the literature, extracted data, and assessed the risk of bias. Meta-analysis was performed using RevMan5.4 software. Results Nine RCTs were included in the final analysis. The quality assessment indicated that one study was rated as Grade A and eight as Grade B, reflecting relatively high study quality. Meta-analysis results demonstrated that PNES significantly improved extubation success rates [relative risk (RR)=1.33, 95%CI 1.09 - 1.62, P=0.006], maximal inspiratory pressure (MIP) [mean difference (MD)=1.36, 95%CI 0.46 - 2.27, P=0.003], and diaphragmatic thickness fraction (DTF) (MD=7.11, 95%CI 0.53 - 13.69, P=0.03) compared with the control group. PNES also significantly reduced the duration of mechanical ventilation (MD=–2.23, 95%CI –3.07- –1.38, P<0.000 01), re-intubation rates (RR=0.35, 95%CI 0.15 - 0.85, P=0.02), and rapid shallow breathing index (RSBI) (MD=–11.57, 95%CI –18.51 - –4.62, P=0.001). Additionally, PNES shortened ICU length of stay (MD=–4.03, 95%CI –5.95 - –2.11, P<0.000 1), with all differences being statistically significant. Conclusion PNES effectively reduces the duration of mechanical ventilation and ICU length of stay, decreases re-intubation rates and RSBI, and improves extubation success, MIP, and DTF in ICU patients. Future high-quality, large-scale, multi-center RCTs are needed to further validate these findings.
Objectives About 12.9-50% patients of SARS (Severe Acute Respiratory Syndrome), require brief mechanical ventilation (MV) to save life. All the reported principles and guidelines for therapy SARS were based on experiences from clinical treatments and facts of inadequacy. Neither prospective randomized controlled trials (RCT) nor other high quality evidences were in dealing with SARS. Our objective is to seek safe and rational non-drugs interventions for patients with severe SARS by retrospectively reviewing clinical studies about MV all over the world, which include clinical guidelines, systematic reviews (SR), Meta-analysis, economic researches and adverse events. Methods To search MEDLINE and Cochrane Library with computer. According to the standards of inclucion or exclusion, the quality of the article which as assessed, and relevant data which were extracted double checked. The Meta-analysis was conducted if the studies had no heterogeneity. Results 14 papers were eligible. Due to the significant heterogeneity between these studies, further Meta-analysis could not be conducted, and the authors’ conclusions were described only. Conclusions The outcome of PPV is better than that of VPV. Patients who underwent PPV had a significantly lower mortality than that of VPV. Of course, the volutrauma should be watched. With low tidal volume and proper PEEP, or decreased FiO2, even permissive hypercapnia, the mortality and length of stay were cut down. Non-invasive mechanical ventilation (NIMV) was effective in treating haemodynamical stable patients, minimizing complications and reducing medical staff infection. Patients with serious dyspnea with PaO2/FiO2lt;200, no profit of NIMV, or couldn’t tolerance hypoxaemia were unlikely to benefit from this technique and needed ventilation with endotracheal intubation. Prone position could improve PaO2/FiO2, NO maybe increased pulmonary perfusion, improved V/Q, and raised oxygenation. Furthermore, Inhaled NO sequentially (SQA) was better than Inhaled NO continuouly (CTA). Some studies implied that practice of protocol-directed weaning from mechanical ventilation implemented by nurses excelled that of traditional physician-directed weaning.
Pressure-support ventilation (PSV) is a form of important ventilation mode. Patient-ventilator synchrony of pressure support ventilation can be divided into inspiration-triggered and expiration-triggered ones. Whether the ventilator can track the patient's inspiration and expiration very well or not is an important evaluating item of the performance of the ventilator. The ventilator should response to the patient's inspiration effort on time and deliver the air flow to the patient under various conditions, such as different patient's lung types and inspiration effort, etc. Similarly, the ventilator should be able to response to the patient's expiration action, and to decrease the patient lung's internal pressure rapidly. Using the Active Servo Lung (ASL5000) respiratory simulation system, we evaluated the spontaneous breathing of PSV mode on E5, Servo i and Evital XL. The following parameters, the delay time before flow to the patient starts once the trigger variable signaling the start of inspiration, the lowest inspiratory airway pressure generated prior to the initiation of PSV, etc. were measured.
ObjectiveTo investigate the clinical characteristics of polymyositis (PM)/dermatomyositis (DM) with acute interstitial pneumonia (AIP) as the presenting symptoms, and identify characteristics of such disease. MethodsA retrospective analysis was conducted on the hospitalized patients with PM/DM with AIP as the presenting symptoms, from October 2009 to June 2015 in the Departemnt of Respiratory Medicine, Guangzhou Institute of Respiratory Diseases. ResultsThey were two males and six females with a mean age of 54.8±7.5 years. The common clinical features included fever (8 cases), shortness of breath (8 cases), rapidly progressive exertional dyspnea (8 cases), dry cough (6 cases), decreased muscle strength (8 cases), and typical rash (7 cases). Electromyography showed neurogenic or myogenic leision in these 8 cases. Muscle biopsy revealed myositis in 7 cases. High resolution CT (HRCT) revealed widespread ground glass patterns in all patients. All patients received noninvasive positive pressure mechanical ventilation on the first hospital day. High dose of methylprednisolone or combination with intravenous cyclophosphamide were initiated on 2.3±1.4 hospital day. Six patients survived to hospital discharge and two patient died. ConclusionsThe most common symptoms in patients of PM/DM with AIP are shortness of breath, progressive exertional dyspnea, and dry cough. Typical rash is seen in most of the patients.The diagnosis can be established by combinating the characteristics of HRCT, electromyography and muscle biopsy. Earlier intervention with noninvasive positive pressure mechanical ventilation and immunosuppressive may improve clinical outcome in patients of PM/DM with AIP.
Objective To explore the feasibility of ultrasound diagnosis of diaphragmatic paralysis in patients with ventilation after congenital heart disease surgery. Methods There were 542 patients with congenital heart disease after surgery, difficult to be weaned off the ventilator or suspected diaphragmatic paralysis of the patients, respectively, in the ventilator continous positive pressure breathing (CPAP) mode and completely independent breathing state, whose ultrasound examination of diaphragm function was conducted to determine the presence of diaphragmatic paralysis in our hospital between January 1, 2013 and April 30, 2016. There were 327 males and 215 females at age of 14±32 months. The results of ultrasound diagnosis between ventilator CPAP mode and completely spontaneous breathing mode were compared. Results Five hundred and forty-two patients underwent ultrasound diaphragmatic examination. The results of bedside ultrasound were completely diagnosed: in completely spontaneous breathing, 82 patients who were diagnosed as diaphragmatic paralysis, including 39 on the right, 25 on the left, 18 on both sides; in CPAP mode, 82 patients who were diagnosed as diaphragmatic paralysis, 38 on the right, left 25, bilateral 19. Using ultrasound in CPAP mode to diagnose diaphragmatic paralysis after congenital heart disease surgery, compared with the completely spontaneous breathing state, the sensitivity was 100.0% and the specificity was 99.9%. Conclusion It is accurate and feasible to diagnose the presence of diaphragmatic paralysis in patients with ventilation after congenital heart disease surgery.