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.
In the clinical practice, the mechanical ventilation is a very important assisting method to improve the patients' breath. Whether or not the parameters set for the ventilator are correct would affect the pulmonary gas exchange. In this study, we try to build an advisory system based on the gas exchange model for mechanical ventilation using fuzzy logic. The gas exchange mathematic model can simulate the individual patient's pulmonary gas exchange, and can help doctors to learn the patient's exact situation. With the fuzzy logic algorithm, the system can generate ventilator settings respond to individual patient, and provide advice to the doctors. It was evaluated in 10 intensive care patient cases, with mathematic models fitted to the retrospective data and then used to simulate patient response to changes in therapy. Compared to the ventilator set only as part of routine clinical care, the present system could reduce the inspired oxygen fraction, reduce the respiratory work, and improve gas exchange with the model simulated outcome.
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 evaluate the relationship between sublingual microcirculation differences and weaning success rate and prognosis in elderly patients with severe pneumonia. Methods A retrospective observation cohort study was conducted. Forty-two elderly patients with severe pneumonia who underwent mechanical ventilation in the intensive care unit of Sir Run Run Hospital, Nanjing Medical University from February 2022 to August 2022 were recruited in the study. They were divided into a high-flow nasal cannula oxygen group (HFNC group, n=33) and a non-invasive positive pressure ventilation group (NIPPV group, n=9) according to the mode of post-weaning ventilation. The differences of N-terminal brain natriuretic peptide precursor (NT-proBNP), cardiac index (CI) and sublingual microcirculation indexes between the two groups were analyzed. The receiver operating characteristic (ROC) curve was used to analyze the predictive value of each parameter on weaning success rate and case fatality rate. Results Compared with the NIPPV group, CI, propotion of perfused vessels (PPV) and perfused vessel density (PVD) were higher, and NT-proBNP and total vessel density (TVD) were lower in the HFNC group (all P<0.05). The prediction value of PPV combined with PVD was the largest, with area under the ROC curve (AUC) of 0.875, sensitivity of 75.8%, specificity of 88.9%. CI, NT-proBNP, CI combined with NT-proBNP, PPV, PVD all had predictive value. Compared with the death group, the survival group had higher CI, central venous-to-arterial carbon dioxide difference [P(v-a)CO2] and PPV. For the prediction value of weaning success, CI combined with NT-proBNP had the largest predictive value, with AUC of 0.919, sensitivity of 81.8%, specificity of 100.0%, followed by CI. NT-proBNP, PPV, PVD, PPV combined with PVD all had predictive value. Compared with the death group, the survival group had higher CI, P(v-a)CO2 and PPV (all P<0.05). For predictive value assessment of 28-day survival rate, CI plus PPV had the largest AUC of 0.875, with sensitivity of 69.4%, and specificity of 100.0%. CI, P(v-a)CO2 and PPV all have predictive value. Conclusions Both CI and PPV can be used as predictors of weaning success rate and survival rate. PPV combined with PVD is an ideal predictor of survival rate.
Objective To develop and validate a nomogram for predicting the risk of weaning failure in elderly patients with severe pneumonia undergoing mechanical ventilation. Methods A retrospective analysis was conducted on the clinical data of 330 elderly patients with severe pneumonia undergoing mechanical ventilation who were hospitalized in our hospital from July 2021 to July 2023. According to their weaning outcomes, they were divided into a successful group (n=213 ) and a failure group (n=117). Univariate analysis and multivariate non-conditional logistic regression analysis were used to explore the factors influencing the weaning failure of mechanical ventilation in elderly patients with severe pneumonia. Results Univariate analysis showed that there were significant differences in age, smoking status, chronic obstructive pulmonary disease, ventilation time, albumin, D-dimer, and oxygenation index levels between the two groups (all P<0.05). Multivariate logistic regression analysis revealed that age ≥65 years, smoking, presence of chronic obstructive pulmonary disease, ventilation time ≥7 days, D-dimer ≥2 000 μg/L, and reduced oxygenation index were risk factors for weaning failure in the elderly patients with severe pneumonia. The nomogram model constructed based on these factors had an area under ROC curve of 0.970 (95%CI 0.952 - 0.989), and the calibration curve demonstrated good agreement between predicted and observed values. Conclusions Age, smoking status, chronic obstructive pulmonary disease, ventilation time, D-dimer, and oxygenation index are influencing factors for weaning failure in elderly patients with severe pneumonia receiving mechanical ventilation. The nomogram model constructed based on these factors exhibits good discrimination and accuracy.
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.
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。
ObjectiveTo investigate the correlation between compliance of clinical respiratory bundle and duration of mechanical ventilation. MethodsThe data of patients who admitted to intensive care unit (ICU)of Cancer Hospital Chinese Academy of Medical Sciences between June 2013 and December 2014 were retrospectively reviewed and analyzed.The patients with respiratory insufficiency who ventilated more than 48 hours were included into the study. ResultsFifty-five patients were enrolled into the final analysis.There were 43 males and 12 females with a mean age of 63.47±12.49 years.The mean sequential organ failure assessment (SOFA)score was 2.8±2.2,and the mean simplified acute physiology score 3 (SAPS3)was 51±14 on ICU admission.The mean duration of mechanical ventilation of all 55 patients was 7.3±5.5 days.The compliance of low tidal volume strategy was 23.6%(13/55).No significant difference was found on duration of mechanical ventilation between the patients who was compliant with low tidal volume strategy and the patients who was not compliant (7.31±7.02 days vs. 7.31±5.07 day,P=0.444).A negative correlation between compliance of protocolized sedation strategy and duration of mechanical ventilation was found by Bivariate spearman correlation analysis (r2=0.312,P<0.001).A negative correlation between compliance of spontaneous awakening trial strategy and duration of mechanical ventilation (r2=0.337,P<0.001)and a negative correlation between compliance of spontaneous breathing trial strategy and duration of mechanical ventilation (r2=0.280,P<0.001)were also found by Bivariate spearman correlation analysis.Multiple linear regression analysis showed that only spontaneous awakening trial strategy was correlated with duration of mechanical ventilation(B=-0.623,P<0.001). ConclusionThe more compliance with clinical respiratory bundle,especially with spontaneous awakening trial strategy,the shorter of duration of mechanical ventilation.The effect of low tidal volume strategy on the duration of mechanical ventilation needs further studies.
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.
Objective To investigate the clinical significance of lateral position ventilation in the treatment of invasive ventilation in patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD). Methods From October 2014 to December 2016, 60 eligible patients with AECOPD who meeting the inclusion criteria were randomly assigned to an intervention group (n=30) or a control group (n=30). Expectorant, antiasthmatic, anti-infective, invasive ventilation, bronchoscopy, analgesic sedation, invasive-noninvasive sequential ventilation, nutritional support, intensive care and other treatment were conducted in two groups, but lateral position ventilation was subsequently performed in the intervention group and the control group used half lateral position. Outcome measurements included pH, PaO2/FiO2, arterial partial pressure of carbon dioxide (PaCO2), heart rate (HR), respiratory rate (R) and air way resistance (Raw) before and one day after invasive ventilation, and duration of control of pulmonary infection (PIC), invasive mechanic ventilation (IMV), mechanic ventilation (MV) and intensive care unit (ICU) stay. Results Compared with before ventilation, the levels of PaO2/FiO2, PaCO2, HR, R and Raw were significantly changed in two groups after ventilation (P<0.05). One day later after ventilation, pH [interventionvs. control: (7.43±0.07) vs. (7.37±0.11)], PaO2/FiO2[(253.52±65.33) mm Hg (1 mm Hg=0.133 kPa) vs. (215.46±58.72) mm Hg] and PaCO2 [(52.45±7.15) mm Hg vs. (59.39±8.44) mm Hg] were statistically significant (P<0.05), but no significant difference was found in HR, R or Raw between two groups (P>0.05). Compared with the control group, PIC [(3.7±1.4) daysvs. (5.3±2.2) days], IMV [(4.0±1.5) days vs. (6.1±3.0) days], MV [(4.7±2.0) days vs. (7.3±3.7) days] and ICU stay [(6.2±2.1) days vs. (8.5±4.2) days] were significantly decreased (P<0.05) in the intervention group. Conclusions In AECOPD patients, invasive ventilation using lateral position ventilation can significantly improve arterial blood gas index, decrease Raw, shorten the time of PIC, IMV, MV and ICU stay.