Beginning Of Mechanical Ventilation Research Articles

Acute kidney injury in elderly patients receiving invasive mechanical ventilation: early versus late onset

BackgroundAcute kidney injury (AKI) is a severe complication in critical patients receiving invasive mechanical ventilation (MV). However, AKI which occurs in the first 48 h after MV (early AKI) and thus likely associated with the MV settings is probably different from AKI occurring following 48 h (late AKI). This study is aimed at exploring the incidence of early and late AKI in elderly patients receiving MV and identifying their different risk factors and outcomes.MethodsThis retrospective, observational, multicenter cohort study consecutively included 3271 elderly patients (≥ 75 years) receiving invasive MV at four medical centers of Chinese PLA General Hospital from 2008 to 2020. The diagnosis of AKI was made following the 2012 KDIGO criteria and categorized into early (≤ 48 h) or late (> 48 h-7 days) according to the time from MV.ResultsThere were totally 1292 cases enrolled for the final analysis. Among them, 376 patients (29.1%) developed early AKI versus 132 (10.2%) developed late AKI. The 28-day mortality rates of the non-AKI, early AKI, and late AKI patients were 14.4, 46.8, and 61.4%, respectively. After 90 days, mortality rates of three groups were 33.2, 60.6, and 72.7%, respectively. Risk factors for early AKI included PaO2/FIO2, serum creatinine, hemoglobin, and positive end-expiratory pressure at the beginning of MV, while those for late AKI were PaO2/FIO2, serum creatinine, and hemoglobin. In the multivariable adjusted analysis, both early AKI (HR = 4.035; 95% CI = 3.166–5.142; P < 0.001) and late AKI (HR = 6.272; 95% CI = 4.654–8.453; P < 0.001) were related to the increased 28-day mortality relative to non-AKI. AKI was significantly related to 90-day mortality: early AKI (HR = 2.569; 95% CI = 2.142–3.082; P < 0.001) and late AKI (HR = 3.692; 95% CI = 2.890–4.716; P < 0.001).ConclusionsAKI mostly develops in the initial 48 h following MV, which is related to the health and MV settings; while AKI occurring following 48 h is not associated with MV settings. Therefore, a strategy for kidney protection in patients with MV should take these differences into consideration.

Association between serum lactate, lactate clearance rate, and 30-day mortality among patients undergoing mechanical ventilation: A retrospective cohort study of MIMIC-III database.

Serum lactate has been used as a prognostic indicator in intensive care unit patients, and however, the single lactate value may not be enough to reflect changes during illness conditions. Herein, this study aims to explore the association between serum lactate and lactate clearance rate and 30-day mortality in patients undergoing mechanical ventilation (MV). Demographic and clinical data of 2628 adults were extracted from the medical information mart for intensive care-III clinical database in this retrospective cohort study. The lactate clearance rate was calculated using the serum lactate at the beginning of MV (T0), and serum lactate at the12 hours after MV beginning (T1). Univariate and multivariate Cox regression analyses were used to screen covariates, and explore the association between serum lactate and lactate clearance rate and 30-day mortality. We also explored these associations in different T0 serum lactate level subgroups. The evaluation indexes were hazard ratios (HRs) and 95% CIs. In addition, receiver operator characteristic (ROC) curve with area under the curve (AUC) was used to reflect the predictive performance of serum lactate and lactate clearance rate on 30-day mortality. A total of 827 (31.47%) mechanically ventilated patients died within 30 days. After adjusting for covariates, elevated T0 (HR = 1.04, 95%CI: [1.02-1.07]) and T1 (HR = 1.07, 95%CI: [1.04-1.10]) serum lactate was both associated with an increased risk of 30-day mortality, while higher lactate clearance rate was negatively associated with the risk of 30-day mortality (HR = 0.64, 95%CI: [0.50-0.81]). Among patients with T0 lactate ≥2 mmol/L, T1 serum lactate ≥4 mmol/L was associated with an increased risk of 30-day mortality, while lactate clearance rate ≥50 was associated with a decreased risk (all P < .05). Moreover, T1 serum lactate had a potential predictive value on 30-day mortality with an AUC of 0.605. Serum lactate and lactate clearance rate were both associated with 30-day mortality in patients undergoing MV. Our results may provide some references for further studies to explore the roles of serum lactate and lactate clearance rate in prognoses of critical patients.

Clinical evaluation of ventilation mode on acute exacerbation of chronic obstructive pulmonary disease with respiratory failure.

At present, understanding of the most effective ventilation methods for treating chronic obstructive pulmonary disease (COPD) patients experiencing acute worsening symptoms and respiratory failure remains relatively limited. This report analyzed the efficiency and side effects of various ventilation techniques used for individuals experiencing an acute COPD exacerbation. To determine whether pressure-controlled ventilation (PCV) can lower peak airway pressures (PAPs) and reduce the incidence of barotrauma compared to volume-controlled ventilation (VCV), without compromising clinical outcomes and oxygenation parameters. We have evaluated 600 patients who were hospitalized due to a severe COPD exacerbation, with 400 receiving mechanical ventilation for the respiratory failure. The participants were divided into two different groups, who were administered either VCV or PCV, along with appropriate management. We thereafter observed patients' attributes, clinical factors, and laboratory, radiographic, and arterial blood gas evaluations at the start and during their stay in the intensive care unit (ICU). We have also employed appropriate statistical methods for the data analysis. Both the VCV and PCV groups experienced significant enhancements in the respiratory rate, tidal volume, and arterial blood gas values during their time in the ICU. However, no significant distinctions were detected between the groups in terms of oxygenation indices (partial pressures of oxygen/raction of inspired oxygen ratio) and partial pressures of carbon dioxide improvements. There was no considerable disparity observed between the VCV and PCV groups in the hospital mortality (32% vs 28%, P = 0.53), the number of days of ICU stay [median interquartile range (IQR): 9 (6-14) d vs 8 (5-13) d, P = 0.41], or the duration of the mechanical ventilation [median (IQR): 6 (4-10) d vs 5 (3-9) d, P = 0.47]. The PCV group displayed lower PAPs compared to the VCV group (P < 0.05) from the beginning of mechanical ventilation until extubation or ICU departure. The occurrence of barotrauma was considerably lower in the PCV group in comparison to the VCV group (6% vs 16%, P = 0.03). Both VCV and PCV were found to be effective in treating patients with acute COPD exacerbation. However, PCV was associated with lower PAPs and a significant decrease in barotrauma, thus indicating that it might be a safer ventilation method for this group of patients. However, further large-scale study is necessary to confirm these findings and to identify the best ventilation approach for patients experiencing an acute COPD exacerbation.

INFLUENCE OF RESPIRATORY SUPPORT STRATEGY DURING CARDIOPULMONARY BYPASS ON LUNGS OXYGENATING FUNCTION

Introduction There are high incidence of pulmonary complications and acute respiratory failure (3,2—28,6%)¹ after cardiac surgery with cardiopulmonary bypass. The study aimed to evaluate the effectiveness of various tactics of respiratory support during cardiopulmonary bypass (CPB) for the prevention of postoperative pulmonary complications. Methods This is a prospective, randomized, controlled clinical study in parallel groups. The study was approved by a local ethics committee. Informed consent was obligatory for all participants. Sixty patients were divided into two groups. In group 1 we provided a continuous positive airway pressure (CPAP) of +5 cm H2O during CPB. In group 2 patients underwent mechanical ventilation with reduced volume (volume control (VC) mode, tidal volume 3 ml / kg of ideal body weight) and respiratory rate of 6 breathes per minute with positive end-expiratory pressure + 5 cm H2O. The primary end-point of the study was the value of the partial pressure of oxygen in arterial blood to oxygen fraction in inhaled gas mixture ratio (paO2/FiO2) at different stages of perioperative management: T1 (after the beginning of mechanical ventilation, T2 (before the CPB), T3 (after CPB), T4 (at the end of the surgery), T5 (upon admission to the ICU), T6 and T7 (6 and 12 hours after surgery, respectively). Secondary end-points were the common lung complications rate (pneumonia, pleural effusion, atelectasis, pneumothorax), the frequency of recruitment maneuvers during the mechanical ventilation, the need for non-invasive ventilation after extubation, the frequency of re-intubation of the trachea. Statistical analysis was carried out in SPSS for Mac v19 (IBM, Inc, USA). Data were presented as mean (±standard deviation) or number (percent). A comparison of the quantitative characteristics was performed using the Mann Whitney U-test. Fisher's exact test was used for the incidence of complications between groups. A p value of less than 0.05 was considered statistically significant. Results The results are presented in Tables 1 and 2. The paO2/FiO2 in the VC group was higher than in the CPAP group at stages T3 and T5. The frequency of recruiting maneuvers in the VC group was lower than in the CPAP group. There was a lower incidence of atelectasis in the VC group than in the CPAP group (Table 2). The low-volume lung ventilation during the CPB is beneficial for oxygenating function of the lungs in comparison with CPAP respiratory support. Discussion The low-volume lung ventilation during the CPB is beneficial for oxygenating function of the lungs in comparison with CPAP respiratory support.

Effects of circadian rhythm on Narcotrend index and target-controlled infusion concentration of propofol anesthesia

BackgroundThe effects of circadian rhythms on drug metabolism and efficacy are being increasingly recognized. However, the extent to which they affect general anesthesia remains unclear. This study aims to investigate the effects of circadian rhythms on anesthetic depth and the concentrations of propofol target-controlled infusion (TCI).MethodsSixty patients undergoing laparoscopic surgeries were sequentially assigned to four groups. Group ND (n = 15): Propofol TCI with Narcotrend monitor during the day (8:00–18:00), Group NN (n = 15): Propofol TCI with Narcotrend monitor during the night (22:00–5:00), Group CLTD (n = 15): Propofol closed-loop TCI guided by bispectral index (BIS) during the day (8:00–18:00), Group CLTN (n = 15): Propofol closed-loop TCI guided by BIS during the night (22:00–5:00). The Narcotrend index, mean arterial pressure (MAP) and heart rate (HR) were compared between group ND and NN at 7 time points, from 5 min before induction to the end of operation. The propofol TCI concentrations, MAP and HR were compared between group CLTD and CLTN at 7 time points, from 5 min after induction to the end of operation.ResultsThe Narcotrend index, MAP, and HR in group NN were lower than those in group ND from the beginning of mechanical ventilation to the end of operation (p < 0.05). The propofol TCI concentrations in group CLTN were lower than those in group CLTD from the beginning of operation to the end of operation (p < 0.05).ConclusionCircadian rhythms have a significant effect on the depth of anesthesia and drug infusion concentrations during propofol TCI. When using general anesthesia during night surgery, the propofol infusion concentration should be appropriately reduced compared to surgery during the day.Trial registrationThe present study was registered on the ClinicalTrials.gov website (NCT02440269) and approved by the Medical Ethics Committee of Southwest Hospital of Third Military Medical University (ethics lot number: 2016 Research No. 93). All patients provided informed written consent to participate in the study.

Monitoring Transcutaneously Measured Partial Pressure of CO2 During Intubation in Critically Ill Subjects.

The risk for severe hypoxemia during endotracheal intubation is a major concern in the ICU, but little attention has been paid to CO2 variability. The objective of this study was to assess transcutaneously measured partial pressure of CO2 ([Formula: see text]) throughout intubation in subjects in the ICU who received standard oxygen therapy, high-flow nasal cannula oxygen therapy, or noninvasive ventilation for preoxygenation. We hypothesized that the 3 methods differ in terms of ventilation and CO2 removal. In this single-center, prospective, observational study, we recorded [Formula: see text] from preoxygenation to 3 h after the initiation of mechanical ventilation among subjects requiring endotracheal intubation. Subjects were sorted into 3 groups according to the preoxygenation method. We then assessed the link between [Formula: see text] variability and the development of postintubation hypotension. A total of 202 subjects were included in the study. The [Formula: see text] values recorded at endotracheal intubation, at the initiation of mechanical ventilation, and after 30 min and 1 h of mechanical ventilation were significantly higher than those recorded during preoxygenation (P < .05). [Formula: see text] variability differed significantly according to the preoxygenation method (P < .001, linear mixed model). A decrease in [Formula: see text] by > 5 mm Hg within 30 min after the start of mechanical ventilation was independently associated with postintubation hypotension (odds ratio = 2.14 [95% CI 1.03-4.44], P = .039) after adjustments for age, Simplified Acute Physiology Score II, COPD, cardiac comorbidity, the use of propofol for anesthetic induction, and minute ventilation at the start of mechanical ventilation. [Formula: see text] variability during intubation is significant and differs with the method of preoxygenation. A decrease in [Formula: see text] after the beginning of mechanical ventilation was associated with postintubation hypotension. (ClinicalTrials.gov registration NCT0388430.).

PCR coupled to electrospray ionization mass spectrometry for microbiological diagnosis and surveillance of ventilator-associated pneumonia.

Etiological diagnosis is essential for anti-infective therapy in patients with ventilator-associated pneumonia (VAP). The present study aimed to evaluate the capacity of sequential PCR coupled to electrospray ionization mass spectrometry (PCR/ESI-MS) tests as a rapid diagnostic technique for patients with VAP. A total of 12 patients diagnosed with VAP were enrolled at the intensive care unit in Zhongshan Hospital, Fudan University. Mini-bronchoalveolar lavage fluid specimens were prospectively collected on VAP 0, 5 and 10 days following the beginning of mechanical ventilation. Routine clinical culture and PCR/ESI-MS were compared for identification of microorganisms in the specimens. A total of 51 bacterial species were detected by either of the two methods. The positive rates of routine clinical culture and PCR/ESI-MS were 38.2 and 88.2%, respectively. Out of the 16 specimens positive in routine cultures, 15 were also positive on PCR/ESI-MS, except for one, from which a mix of three distinct bacterial isolates were reported by culture. Among the 50 bacterial species identified by PCR/ESI-MS, 15 (35.7%) of the common VAP pathogens were confirmed by paired culture. Furthermore, of the 16 bacterial isolates that were finally confirmed to be responsible for VAP, 14 were identified by a sequential PCR/ESI-MS test concurrently when the culture results were obtained. PCR/ESI-MS identified pathogens that may cause VAP in 8 subjects prior to the occurrence of associated clinical manifestations. To conclude, PCR/ESI-MS was a potential rapid technique for diagnosis of VAP within 6 h. Regular respiratory specimen monitoring using PCR/ESI-MS provides information for selecting appropriate and adequate antibiotic therapies in ventilated patients.

Surgical Tracheostomies in COVID-19 Patients: Indications, Technique, and Results in a Second-Level Spanish Hospital.

ObjectiveThe main purpose of this work is to describe the sociodemographic and clinical characteristics of intensive care unit (ICU) patients in a second-level hospital in Madrid, Spain, focusing in those who underwent surgical tracheostomy during the coronavirus disease 2019 (COVID-19) pandemic. The surgical technique and associated complications are also detailed.Study DesignObservational and historical cohort.SettingSingle center.MethodsEighty-three intubated COVID-19 patients were analyzed. Thirty bedside surgical tracheostomies had been performed following our safety protocol.ResultsData from 83 patients admitted to the ICU in Infanta Leonor University Hospital were collected; 74.7% were male. The average age was 59.7 years. The main comorbidities found were hypertension in 51.8%, diabetes mellitus in 25.3%, asthma in 7.2%, and chronic obstructive pulmonary disease in 3.6%. A surgical tracheostomy was carried out in 36.1% of patients who needed a prolonged intubation. The most frequent complication of the surgical procedure, bleeding, occurred in 30%, but the majority were mild and ceased with compression only. The most relevant complication was local infection, which occurred in 26.7% of patients. There were statistically significant differences in the time from the beginning of mechanical ventilation until weaning between tracheostomized and nontracheostomized patients. The mortality rate of patients who underwent tracheostomy was 56.7%. Despite severe acute respiratory syndrome coronavirus 2 being highly contagious and tracheostomy being considered a high-risk procedure, our rate of infected ear, nose, and throat specialists was only 11.8%.ConclusionIn our experience, bedside surgical tracheostomy is a safe procedure in COVID-19 patients when safety protocols are followed.

Critical Illness Polyneuropathy in Children with Infectious Diseases

Our goal was to establish electrophysiological features of critical illness polyneuropathy in children with infectious diseases. Materials and Methods: We evaluated peripheral nervous system involvement in 67 critically ill children, admitted in ICU with different types of infectious diseases (viral encephalitis, meningoencephalitis, meningitis, acute gastroenteritis). Age of the group varied from 4 months to 17 years. All patients underwent conduction studies and neurological investigation. Sensory and motor fibers of n. ulnaris et n. medianus, motor fibers of n. Tibialis and sensory fibers of n. Suralis were tested. Lowering of the amplitudes, conduction velocity slowing and asymmetry were accounted for the motor and sensory fibers. Results: In 47 cases (n=71) diagnosis of critical illness polyneuropathy (CIP) was established. Lesions mostly involved lower limbs nerves. According to our data, severe course of CIP was seen in 40% of all cases. Average time of CIP onset in children was 5-7 days from the beginning of mechanical ventilation. Conclusions: Critical illness polyneuropathy in children with infectious diseases is a severe condition which may lead to the disability of the patients. Average time of its onset is the 5-7 days from the beginning of the mechanical ventilation in 71% of the patients. More often sensory and motor fibers of lower limbs nerves are affected. Conduction studies is a valuable tool in diagnostic process in establishing the critical illness polyneuropathy in children with infectious diseases. Keywords: Critical illness, critical illness polyneuropathy, children, electromyography.

PREDICTION VALUE OF OXYGENATION INDEX AS PREDICTOR FOR POSTOPERATIVE PULMONARY COMPLICATIONS IN UROLOGIC SURGERY

Introduction: It is believed that pressure/flow (P/F) ratio (arterial oxygen to inspired oxygen fraction) does not give the best expression of oxygenation status in mechanically ventilated patients. Therefore, a new oxygenation index (OI) where the mean airway pressure (MAP) is incorporated (PaO2/FiOxMAP) is showed as superior to P/F in expression of the lung oxygenation status. In this article we wanted to assess the prediction value of OI calculated during urological surgeries as a predictive marker for developing postoperative pulmonary complications (PPC).&#x0D; Material and methods: We evaluated all elective urologic patients operated in general endotracheal anesthesia, aged 18 to 65 years, without any known history of respiratory disease for the period from January till December 2017. We calculated the P/F ratio and the OI at three time points: after induction in general endotracheal anesthesia in the beginning of mechanical ventilation, 1 hour after induction in anesthesia, and at the end of the surgery before weaning the mechanical ventilation. The primary outcomes were PPC defined by European Society of Anesthesia. The second outcomes were: length of hospital stay, admission to intensive care unit (ICU) and mortality. &#x0D; Results: A total of 240 patients who met the inclusion criteria were included in this evaluation and finally analyzed. PPC were diagnosed in 25% of patients and respectively 75% were without complications. Postoperative hospital stay was longer in PPC group no matter they were operated laparoscopically or with classic open surgery (PPC laparoscopy 4.9 ± 2.2 vs. non PPC laparoscopy 3.3 ± 1.7, PPC laparotomy 6.8 ± 5.2 vs. non PPC 5.6 ± 2.1 laparotomy). Ten patients were admitted to ICU, 8 from PPC group and 2 from non PPC group. In PPC group patients were admitted to ICU for mean 3.7 ± 2.4 days, and in non PPC group patients were hospitalized in ICU only for 2 days. All evaluated patients were discharged from the hospital and no mortality was observed in the 30 postoperative days.&#x0D; In the univariate and multivariate logistic regression analysis neither OI nor P/F were significantly associated with PPC.&#x0D; Conclusion: This study does not offer a conclusive answer to the prediction value of OI for PPC. It would be fruitful to pursue further research about predictive variables for pulmonary complications.

Comparison of effect of propofol and sevoflurane on pulmonary function, inflammatory factors and postoperative pulmonary infection in elderly patients with esophageal carcinoma

Objective To explore the effect of propofol on pulmonary function, inflammatory factors and postoperative pulmonary infection in elderly patients with esophageal carcinoma, and to provide data for prevention and control of nosocomial infection. Methods From January 2011 to December 2015, 155 elderly patients with esophageal cancer in Lishui Central Hospital were selected and randomly divided into control group (C group, n=70) and observation group (O group, n=85) according to the digital table.In the maintenance of anesthesia, O group was given propofol, C group was given sevoflurane.The alveolar arterial oxygen partial pressure difference(PA-aO2), respiratory index(RI) and oxygenation index(OI) of the two groups were observed at different time points.The levels of IL-1, IL-6 and IL-10 in serum were measured at different time points, and the pulmonary infections were observed after operation. Results At 30min, 60min, 90min after ventilation in the two groups, the PA-aO2, RI were higher than the beginning of mechanical ventilation, OI were lower than the beginning of mechanical ventilation (t=7.266, 23.451, 9.572, 8.009, 30.836, 17.158, 4.908, 21.237, 21.350, 7.010, 23.644, 10.039, 9.099, 34.254, 16.679, 8.217, 35.434, 22.160, all P 0.05]. Conclusion Elderly patients with esophageal cancer undergoing radical operation of propofol, the effects of propofol on pulmonary function, inflammatory factors are less, the incidence of postoperative pulmonary infection is low, it has good clinical application value. Key words: Esophageal Neoplasms; Esophagectomy; Propofol; Sevoflurane; Aged

The impacts of baseline ventilator parameters on hospital mortality in acute respiratory distress syndrome treated with venovenous extracorporeal membrane oxygenation: a retrospective cohort study

BackgroundVenovenous extracorporeal membrane oxygenation (VV-ECMO) is a valuable life support in acute respiratory distress syndrome (ARDS) in adult patients. However, the success of VV-ECMO is known to be influenced by the baseline settings of mechanical ventilation (MV) before its institution. This study was aimed at identifying the baseline ventilator parameters which were independently associated with hospital mortality in non-trauma patients receiving VV-ECMO for severe ARDS.MethodsThis retrospective study included 106 non-trauma patients (mean age: 53 years) who received VV-ECMO for ARDS in a single medical center from 2007 to 2016. The indication of VV-ECMO was severe hypoxemia (PaO2/ FiO2 ratio < 70 mmHg) under pressure-controlled MV with peak inspiratory pressure (PIP) > 35 cmH2O, positive end-expiratory pressure (PEEP) > 5 cmH2O, and FiO2 > 0.8. Important demographic and clinical data before and during VV-ECMO were collected for analysis of hospital mortality.ResultsThe causes of ARDS were bacterial pneumonia (n = 41), viral pneumonia (n = 24), aspiration pneumonitis (n = 3), and others (n = 38). The median duration of MV before ECMO institution was 3 days and the overall hospital mortality was 53% (n = 56). The medians of PaO2/ FiO2 ratio, PIP, PEEP, and dynamic pulmonary compliance (PCdyn) at the beginning of MV were 84 mmHg, 32 cmH2O, 10 cmH2O, and 21 mL/cmH2O, respectively. However, before the beginning of VV-ECMO, the medians of PaO2/ FiO2 ratio, PIP, PEEP, and PCdyn became 69 mmHg, 36 cmH2O, 14 cmH2O, and 19 mL/cmH2O, respectively. The escalation of PIP and the declines in PaO2/ FiO2 ratio and PCdyn were significantly correlated with the duration of MV before ECMO institution. Finally, the duration of MV (OR: 1.184, 95% CI: 1.079–1.565, p < 0.001) was found to be the only baseline ventilator parameter that independently affected the hospital mortality in these ECMO-treated patients.ConclusionSince the duration of MV before ECMO institution was strongly correlated to the outcome of adult respiratory ECMO, medical centers are suggested to find a suitable prognosticating tool to determine the starting point of respiratory ECMO among their candidates with different duration of MV.Trial registrationThis study reported a health care intervention on human participants and was retrospectively registered. The Chang Gung Medical Foundation Institutional Review Board approved the study (no. 201601483B0) on November 23, 2016. All of the data were extracted from December 1, 2016, to January 31, 2017.

Influential factors for mechanical ventilation offline in patients with severe pneumonia

To determine the risk factors for mechanical ventilation offline in patients with severe pneumonia. Th e data of 59 patients, who were admitted to the First Hospital of Changsha because of severe pneumonia and required mechanical ventilation between June 2011 and December 2013, were reviewed retrospectively. The patients were divided into two groups: a successful weaned group (n=31) and a failure group (n=28). Th e patients' background, laboratory and bacteriological examinations at the beginning of mechanical ventilation were recorded. All the indexes were analyzed by univariate analysis and logistic regression analysis. Univariate analysis showed that there was no significant difference in gender and age in the 2 groups (P>0.05). Smoker, APECHE II score, D-dimer and brain natriuretic peptide (BNP) concentration in the success weaned group were lower than those in the failure group. The difference between the 2 groups was significant (P<0.05). The serum albumin level in patients of the success weaned group at the time of entering respiratory intensive care unit was higher than that in the failure group, with significant difference (P<0.05). The logistic regression analysis showed that the high concentration of D-dimer, lung diseases based on thoracic CT and low serum albumin were independent risk factors for mechanical ventilation offline in severe pneumonia patients. The severe pneumonia patients with low albumin, high concentration of D-dimer and lung diseases should be comprehensive evaluated and receive treatment, which is beneficial to the mechanical ventilation offline.

Is there a place for pressure-support ventilation and high positive end-expiratory pressure combined to alpha-2 agonists early in severe diffuse acute respiratory distress syndrome?

Acute respiratory distress syndrome (ARDS) is associated with a high mortality linked primarily to co-morbidities (sepsis, cardiac failure, multiple organ failure, etc.). When the lung is the single failing organ, quick resolution of ARDS should skip some complications arising from a prolonged stay in the critical care unit. In severe ARDS (PaO2/FIO2=P/F<100 with positive end-expiratory pressure (PEEP)⩾5cm H2O), current recommendations are to intubate the trachea of the patient and use mechanical ventilation, low tidal volume, high PEEP, prone positioning and possibly neuromuscular blockade in association with intravenous sedation.Another strategy is possible. Firstly, spontaneous ventilation (SV) coupled with pressure support (PS) ventilation and high PEEP is possible from tracheal intubation onwards, with the possible exception of the short period following immediately tracheal intubation. Secondly, using alpha-2 adrenergic agonists (e.g. clonidine, dexmedetomidine) can provide first-line sedation from the beginning of mechanical ventilation, as they preserve respiratory drive, lower oxygen consumption and pulmonary hypertension and increase diuresis. Alpha-2 agonists are to be supplemented, if appropriate, by drugs devoid of effect on respiratory drive (neuroleptics, etc.). The expected benefits would be to prevent acquired diaphragmatic weakness, accumulation of sedation, cognitive dysfunction, and presumably improved outcome. This hypothesis should be tested in a double blind randomized controlled trial.

Effects of Manual Rib Cage Compressions on Expiratory Flow and Mucus Clearance During Mechanical Ventilation*

We investigated the effects of two different types of manual rib cage compression on expiratory flow and mucus clearance during prolonged mechanical ventilation in pigs. Prospective randomized animal study. Animal research facility, University of Barcelona, Spain. Nine healthy pigs. Pigs were tracheally intubated, sedated, paralyzed, and mechanically ventilated. The animals were prone on a surgical bed in the anti-Trendelenburg position. The experiments were carried out at approximately 60 and 80 hrs from the beginning of mechanical ventilation. Two types of manual rib cage compressions were tested: Hard and brief rib cage compressions synchronized with early expiratory phase (hard manual rib cage compression) and soft and gradual rib cage compressions applied during the late expiratory phase (soft manual rib cage compression). The interventions were randomly applied for 15min with a 15-min interval between treatments. Respiratory flow and mucus movement were assessed during the interventions. Respiratory mechanics and hemodynamics were assessed prior to and after the interventions. Peak expiratory flow increased to 60.1±7.1L/min in comparison to 51.2±4.6L/min without treatment (p < 0.0015) and 48.7±4.3L/min with soft manual rib cage compression (p = 0.0002). Similarly, mean expiratory flow increased to 28.4±5.2L/min during hard manual rib cage compression vs. 15.9±2.2 and 16.6±2.8L/min without treatment and soft manual rib cage compression, respectively (p = 0.0006). During hard manual rib cage compression, mucus moved toward the glottis (1.01 ± 2.37mm/min); conversely, mucus moved toward the lungs during no treatment and soft manual rib cage compression, -0.28 ± 0.61 and -0.15±0.95mm/min, respectively (p = 0.0283). Soft manual rib cage compression slightly worsened static lung elastance and cardiac output (p = 0.0391). Hard manual rib cage compression improved mucus clearance in animals positioned in the anti-Trendelenburg position. The technique appeared to be safe. Conversely, soft manual rib cage compression was not effective and potentially unsafe. These findings corroborate the predominant role of peak expiratory flow on mucus clearance.

Change of respiratory mechanics at different intra-abdominal pressures and position change during laparoscopic surgery

Change of respiratory mechanics at different intra-abdominal pressures and position change during laparoscopic surgery

Factors influencing weaning from mechanical ventilation in elderly patients with severe pneumonia

The purpose of this study was to determine the factors that adversely affect the weaning of elderly patients with community-acquired pneumonia from mechanical ventilation. This study retrospectively investigated the medical records of 71 elderly patients (65 years or older) who were admitted to the hospital because of community-acquired pneumonia and required mechanical ventilation between January 2003 and December 2007. The patients were divided into two groups: group A, which included 33 patients who were successfully weaned from mechanical ventilation, and group B, which included 38 patients who could not be weaned from mechanical ventilation. The study compared the patients' background, vital signs, and laboratory and bacteriological examinations at the beginning of mechanical ventilation. A multiple logistic regression analysis was performed to identify the factors associated with difficulties in weaning patients from mechanical ventilation. In group B, there were significantly more smokers (P < 0.05) and more patients with emphysematous changes on thoracic CT (P < 0.05). In group A, the concentrations of total serum protein (P < 0.05) and albumin (P < 0.05) were significantly higher. A multiple logistic regression analysis revealed that patients with community-acquired pneumonia who showed emphysematous changes on thoracic CT (OR = 4.92, 95%CI 1.08-22.46) and/or a low concentration of serum albumin <3.0 g/dL (OR = 4.25, 95%CI 1.17-15.45) had difficulty being weaned from mechanical ventilation. Our study suggests that elderly patients with community-acquired pneumonia with emphysematous changes on thoracic CT and/or a low concentration of serum albumin level have difficulty being weaned from mechanical ventilation.

Adrenomedullin attenuates ventilator-induced lung injury in mice

BackgroundMechanical ventilation (MV) is a life-saving intervention in acute respiratory failure without any alternative. However, even protective ventilation strategies applying minimal mechanical stress may evoke ventilator-induced lung injury (VILI). Adjuvant...

How is Mechanical Ventilation Employed in a Pediatric Intensive Care Unit in Brazil?

OBJECTIVE:to investigate the relationship between mechanical ventilation and mortality and the practice of mechanical ventilation applied in children admitted to a high-complexity pediatric intensive care unit in the city of São Paulo, Brazil.DESIGN:Prospective cohort study of all consecutive patients admitted to a Brazilian high-complexity PICU who were placed on mechanical ventilation for 24 hours or more, between October 1st, 2005 and March 31st, 2006.RESULTS:Of the 241 patients admitted, 86 (35.7%) received mechanical ventilation for 24 hours or more. Of these, 49 met inclusion criteria and were thus eligible to participate in the study. Of the 49 patients studied, 45 had chronic functional status. The median age of participants was 32 months and the median length of mechanical ventilation use was 6.5 days. The major indication for mechanical ventilation was acute respiratory failure, usually associated with severe sepsis / septic shock. Pressure ventilation modes were the standard ones. An overall 10.37% incidence of Acute Respiratory Distress Syndrome was found, in addition to tidal volumes > 8 ml/kg, as well as normo- or hypocapnia. A total of 17 children died. Risk factors for mortality within 28 days of admission were initial inspiratory pressure, pH, PaO2/FiO2 ratio, oxygenation index and also oxygenation index at 48 hours of mechanical ventilation. Initial inspiratory pressure was also a predictor of mechanical ventilation for periods longer than 7 days.CONCLUSION:Of the admitted children, 35.7% received mechanical ventilation for 24 h or more. Pressure ventilation modes were standard. Of the children studied, 91% had chronic functional status. There was a high incidence of Acute Respiratory Distress Syndrome, but a lung-protective strategy was not fully implemented. Inspiratory pressure at the beginning of mechanical ventilation was a predictor of mortality within 28 days and of a longer course of mechanical ventilation.

Effects of sevoflurane and desflurane on respiratory mechanics after tracheal intubation in children.

Tracheal intubation causes a reflex tracheal constriction that leads to increased airway resistance. Inhalation anesthetics can prevent or minimize this response. Therefore, this study was conducted to evaluate the effect of 1 MAC sevoflurane or desflurane on respiratory mechanics in children after anesthetic induction using propofol and tracheal intubation. Sixty children undergoing elective surgery with tracheal intubation were assigned into two groups at random, a 1 MAC concentration of sevoflurane (n = 30) and a desflurane (n = 30) group. Anesthesia was induced using propofol (1.5 mg/kg) and tracheal intubation was facilitated using rocuronium (0.6 mg/kg). A respiratory profile monitor was used to measure the respiratory resistance, dynamic compliance and peak inspiratory airway pressure. The measurements were made at three time points, after three inspirations from the beginning of mechanical ventilation (baseline) and at 5 and 10 min after the administration of inhalation anesthetics. Sevoflurane and desflurane led to a significant decrease in respiratory resistance and increased dynamic compliance at 5 and 10 min when compared to baseline. There were no significant differences in respiratory resistance and dynamic compliance between the two groups. A 1 MAC concentration of sevoflurane and desflurane has a similar bronchodilatory effect after tracheal intubation in children.