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.
Post operational recovery from cardiac surgery can be affected by many factors, including preoperative, intraoperative, and postoperative factors. Prolonged mechanical ventilation (PMV) , one of the major complications, has been widely accepted as a measure to evaluate the performance and outcomes of cardiac surgeries. Great progress has been made in the studies of risk factors contributing to PMV following cardiac surgeries in recent years. However, no clear and effective measures and approaches are available yet to prevent PMV. In this review, the authors try to summarize the risk factors that are associated with PMV throughout the perioperative period of cardiac surgery, as well as possible interventions when applicable.
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.
Objective To investigate the curve correlation between ventilation pressure and tidal volume in assisted mechanical ventilation with facemask during anesthesia induction. Methods Between January and August 2015, 120 patients, American Society of Anesthesiology Ⅰ-Ⅱ, undergoing selective gynecological surgery were randomly divided into four groups: groups P5, P10, P15 and P20, with 30 patients in each group. Mask ventilation pressure for the four groups were respectively 5, 10, 15 and 20 cm H2O (1 cm H2O=0.098 kPa). Patients were ventilated by preset ventilation pressure and frequency based on different groups after loss of consciousness. Mean ventilation volume (mean value of three tidal volumes) and end-tidal carbon dioxide pressure (PetCO2) were recorded for analysis. Results There was no significant difference among the four groups in patient’s general condition (P>0.05). The tidal volume of assisted mechanical ventilation increased with ventilation pressure degrees, and the differences among the four groups were significant (P<0.05). After curve regression analysis, tidal volume and ventilation pressure showed a positive linear correlation when ventilation pressure was set at 5-20 cm H2O, and the correlation equation was: tidal volume = 33.612×ventilation pressure-53.155. PetCO2 in P5 group was lower than those in the other three groups (P<0.05), while there were no significant differences among groups P10, P15 and P20 (P>0.05). Conclusion When ventilation pressure is set at 5-20 cm H2O in assisted mechanical ventilation with facemask during anesthesia induction, tidal volume and ventilation pressure show a positive linear correlation.
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.
Objective To evaluate the efficacy of lung-protective strategies of ventilation (LPSV) in acute respiratory distress syndrome (ARDS) patients after thoracic operation. Methods-Thirtyseven ARDS patients without preoperative complications who had underwent thoracic surgery successfully were divided into the conventional mechanical ventilation group (CMV group, n=20) and lungprotective strategies of ventilation group (LPSV group，n=17). Results of arterial blood gas, index of oxygenation (PaO2/FiO2), airway plateau pressure (Pplat), inspiration peak pressure (PIP), PEEP, after ventilation treatment 24 h and mechanical ventilation time， pulmonary barotrauma and so on were observed. Results The mechanical ventilation time， pulmonary barotrauma and mortality of the LPSV group were 7.3d, 5.9％ and 29.4％ respectively, which were significantly better than those in the CMV group(17.6d，15.0％ and 60.0％, Plt;0.05). peak inflation pressure (PIP)，Pplat(plat pressure) in the LPSV group were significantly lower than those in the CMV group (Plt;0.05). However, there were no significant differences including arterial oxygen saturation (SaO2),pH, partial pressure of carbon dioxide in artery (PaCO2) and PaO2/FiO2 in two groups. Conclusion LPSV is more effective for the patients in the ARDS patients after thoracic operation compared to CMV, which can markedly reduce the ventilatorinduced lung injuryand (VILI) and mortality.
Objective To assess the risk factors associated with extubation failure in patients who had successfully passed a spontaneous breathing trial.Methods Patients receiving invasive mechanical ventilation for over 48 h were enrolled in the study，they were admitted into Emergency ICU of Zhongshan Hospital during May 2006 and Oct.2007.A spontaneous breathing trial was conducted by a pressure support of 7 cm H2O for 30 min.Clinical data were prospectively recorded for the patient receiving full ventilatory support before and after the spontaneous breathing trial.Regarding the extubation outcome，patients were divived into extubation success group and extubation failure group.Results A total of 58 patients with a mean（±SD） age of 69.4±12.7 years passed spontaneous breathing trial and were extubated.Extubation failure occurred in 11 patients（19%）.The univariate analysis indicated the following associations with extubation failure：elderly patients（78.1±7.9 years vs 67.4±15.1years，Plt;0.05），higher rapid shallow breathing index（RSBI） value（83±12 breaths·min-1·L-1 vs 68±19 breaths·min-1·L-1，Plt;0.05）and excessive respiratory tract secretions（54.5％ vs 21.3％，Plt;0.05）.Conclusion Among routinely measured clinical variables，elderly patients，higher RSBI value and amount of respiratory tract secretions were the valuable index for predicting extubation failure despite a successful spontaneous breathing trial.
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.
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.
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.