Search

BACKGROUND: Patients who are obese are at risk for developing high pleural pressure, which leads to alveolar collapse. Esophageal pressure (P(es)) can be used as a surrogate for pleural pressure and can be used to guide PEEP titration. Although recent clinical data on P(es)-guided PEEP has shown no benefit, its utility in the subgroup of patients who are obese has not been studied. METHODS: The Medical Information Mart for Intensive Care-III critical care database was queried to gather data on P(es) in subjects on mechanical ventilation. P(es) in obese and non-obese groups were compared, and a subgroup analysis was performed in subjects with class III obesity. Thereafter, empirical and P(es)-guided PEEP protocols of a recently published trial were theoretically applied to the obese group and ventilator outcomes were compared. RESULTS: A total of 105 subjects were included in the study. The average end-expiratory P(es) in the obese group was 18.8 ± 5 cm H(2)O compared with 16.8 ± 4.8 cm H(2)O in the non-obese group (P < .05). If P(es)-guided PEEP protocol was to be applied to those in the obese group, then the PEEP setting would be significantly higher than empirical PEEP setting. These findings were accentuated in the subgroup of subjects with class III obesity. CONCLUSIONS: Individualization of PEEP with P(es) guidance may have a role in patients who are obese.

BackgroundSurveillance of ventilator-associated events (VAEs) as defined by the National Healthcare Safety Network (NHSN) is performed at many US trauma centers and considered a measure of healthcare quality. The surveillance algorithm relies in part on increases in positive end-expiratory pressure (PEEP) to identify VAEs. The purpose of this cohort study was to evaluate the effect of initiating mechanically ventilated trauma patients at marginally higher PEEP on incidence of VAEs.MethodsAnalysis of level-1 trauma center patients mechanically ventilated 2+ days from 2017 to 2018 was performed after an institutional ventilation protocol increased initial PEEP setting from 5 (2017) to 6 (2018)cm H2O. Incidence of VAEs per 1000 vent days was compared between PEEP groups. Logistic regression modelling was performed to evaluate the impact of the PEEP setting change adjusted to account for age, ventilator days, injury mechanism and injury severity.Results519 patients met study criteria (274 PEEP 5 and 245 PEEP 6). Rates of VAEs were significantly reduced among patients with initial PEEP 5 versus 6 (14.61 per 1000 vent days vs. 7.13 per 1000 vent days; p=0.039). Logistic regression demonstrated that initial PEEP 6 was associated with 62% reduction in VAEs.ConclusionsOur data suggest that an incrementally increased baseline PEEP setting was associated with a significantly decreased incidence of VAEs among trauma patients. This minor change in practice may have a major impact on a trauma center’s quality metrics.Level of evidenceIV.

BACKGROUND: Low-tidal-volume ventilation may be associated with repetitive opening and closing of terminal airways. The use of PEEP is intended to keep the alveoli open. No method of adjusting the optimal PEEP has shown to be superior or to improve clinical outcomes. We conducted a pilot study to evaluate the effect of setting an individualized level of PEEP at the highest compliance on oxygenation, multiple-organ-dysfunction, and survival in subjects with ARDS. METHODS: Subjects with ARDS ventilated with low tidal volumes and limitation of airway pressure to 30 cm H2O were randomized to either a compliance-guided PEEP group or an FIO2-guided group. RESULTS: Of the 159 patients with ARDS admitted during the study period, 70 met the inclusion criteria. Subjects in the compliance-guided group showed nonsignificant improvements in PaO2/FIO2 during the first 14 days, and in 28-day mortality (20.6% vs. 38.9%, P = .12). Multiple-organ-dysfunction-free days (median 6 vs 20.5 d, P = .02), respiratory-failure-free days (median 7.5 vs 14.5 d, P = .03), and hemodynamic-failure-free days (median 16 vs 22 d, P = .04) at 28 days were significantly lower in subjects with compliance-guided setting of PEEP. CONCLUSIONS: In ARDS subjects, protective mechanical ventilation with PEEP application according to the highest compliance was associated with less organ dysfunction and a strong nonsignificant trend toward lower mortality. ClinicalTrials.gov Number [NCT01119872][1]. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT01119872&atom=%2Frespcare%2F58%2F9%2F1416.atom

Introduction Direct comparison of the relative efficacy of different recruitment maneuvers (RMs) for patients with acute respiratory distress syndrome (ARDS) via clinical trials is difficult, due to the heterogeneity of patient populations and disease states, as well as a variety of practical issues. There is also significant uncertainty regarding the minimum values of positive end-expiratory pressure (PEEP) required to ensure maintenance of effective lung recruitment using RMs. We used patient-specific computational simulation to analyze how three different RMs act to improve physiological responses, and investigate how different levels of PEEP contribute to maintaining effective lung recruitment. Methods We conducted experiments on five ‘virtual’ ARDS patients using a computational simulator that reproduces static and dynamic features of a multivariable clinical dataset on the responses of individual ARDS patients to a range of ventilator inputs. Three recruitment maneuvers (sustained inflation (SI), maximal recruitment strategy (MRS) followed by a titrated PEEP, and prolonged recruitment maneuver (PRM)) were implemented and evaluated for a range of different pressure settings. Results All maneuvers demonstrated improvements in gas exchange, but the extent and duration of improvement varied significantly, as did the observed mechanism of operation. Maintaining adequate post-RM levels of PEEP was seen to be crucial in avoiding cliff-edge type re-collapse of alveolar units for all maneuvers. For all five patients, the MRS exhibited the most prolonged improvement in oxygenation, and we found that a PEEP setting of 35 cm H2O with a fixed driving pressure of 15 cm H2O (above PEEP) was sufficient to achieve 95% recruitment. Subsequently, we found that PEEP titrated to a value of 16 cm H2O was able to maintain 95% recruitment in all five patients. Conclusions There appears to be significant scope for reducing the peak levels of PEEP originally specified in the MRS and hence to avoid exposing the lung to unnecessarily high pressures. More generally, our study highlights the huge potential of computer simulation to assist in evaluating the efficacy of different recruitment maneuvers, in understanding their modes of operation, in optimizing RMs for individual patients, and in supporting clinicians in the rational design of improved treatment strategies.

Lung recruitment is used to improve oxygenation and decrease the risk of ventilator induced lung injuries. Assessing the potential of recruitability is a pre-requisite for a rational recruitment strategy and setting of PEEP. Using a low flow pressure-volume loop is helpful to assess the potential of recruitability at the bedside. For patients with a high potential of recruitability, recruitment maneuvers are efficient with an appropriate setting of PEEP to maintain the lung recruited. Recruitment maneuvers use pressures from 40 to 60 cmH2O for a short period of time, either with the sustained inflation or the staircase method. PEEP setting after the maneuver is important; a decreasing PEEP trial is a useful practical method.

In patients with acute lung injury the knowledge of recruitable lung is useful for a physiological PEEP setting. The quantitative lung CT scan analysis remains the reference method [1]. However, it is time consuming and often it is not applicable in clinical management. The PV curve at two PEEP levels has been proposed as an alternative method [2]. The aim of this study was to evaluate the accuracy of these two methods in predicting the lung recruitability.

Mechanical ventilation implies the risk of ventilator induced lung injury (VILI). One of the goals of mechanical ventilation is to sustain alveolar recruitment while avoiding excessive lung inflation. To achieve this goal the patient should be ventilated within that range of the PV-loop, where the compliance of the respiratory system is maximal. A PEEP controller was designed to adapt the PEEP setting such as the patient is ventilated within the range of maximal compliance. This method was implemented in the automatic ventilator control system AUTOPILOT-BT.

ASV (Adaptive-Servo Ventilator) is recognized as one of the effective option for treatment of heart failure, such as repeat readmission in treatment-resistant. In heart failure patients it is said that the Frank-Starling curve is improved by the adequate PEEP by ASV. However excessive PEEP leads to decrease in stroke volume (SV). It has been difficult to determine the value of the adequate PEEP in the clinical up to the present. To patient who introduced the ASV in our hospital, PEEP is raised adequate from 2cmH2O to 15cmH2O to assess the SV using AESCULON mini is a non-invasive cardiac output monitor. We will report on two cases which introduced ASV in heart failure due to ischemic heart disease. First case showed SV 48ml/CI 1.9L/min/m without using ASV, SV 53ml/CI 2.0 L/min/m in PEEP 5cmH2O, SV 63ml/CI 2.3 L/min/m in PEEP13cmH2O. It obtained the elevation of SV in PEEP 13cmH2O. Second case showed SV 60ml/CI 2.6 L/min/m 2 without using ASV, SV 55ml/CI 2.5 L/min/m in PEEP5cmH2O, SV 51ml/CI 2.3 L/min/m 2 in PEEP15cmH2O. Excessive PEEP leads to decrease in SV. PEEP is being fixed to 5cmH2O in the initial state of ASV. In many cases, it has been used without changing the settings. It may be important to adjust the PEEP setting for each case and condition.

ASV (Adaptive-Servo Ventilator) is recognized as one of the effective option for treatment of heart failure, such as repeat readmission in treatment-resistant. In heart failure patients it is said that the Frank-Starling curve is improved by the adequate PEEP by ASV. However excessive PEEP leads to decrease in stroke volume (SV). It has been difficult to determine the value of the adequate PEEP in the clinical up to the present. To patient who introduced the ASV in our hospital, PEEP is raised adequate from 2cmH2O to 15cmH2O to assess the SV using AESCULON mini is a non-invasive cardiac output monitor. We will report on two cases which introduced ASV in heart failure due to ischemic heart disease. First case showed SV 48ml/CI 1.9L/min/m without using ASV, SV 53ml/CI 2.0 L/min/m in PEEP 5cmH2O, SV 63ml/CI 2.3 L/min/m in PEEP13cmH2O. It obtained the elevation of SV in PEEP 13cmH2O. Second case showed SV 60ml/CI 2.6 L/min/m 2 without using ASV, SV 55ml/CI 2.5 L/min/m in PEEP5cmH2O, SV 51ml/CI 2.3 L/min/m 2 in PEEP15cmH2O. Excessive PEEP leads to decrease in SV. PEEP is being fixed to 5cmH2O in the initial state of ASV. In many cases, it has been used without changing the settings. It may be important to adjust the PEEP setting for each case and condition.

The effect of positive end-expiratory pressure (PEEP) on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) has been reported by several investigators, without any consensus being reached. Acute neurological and neurosurgical patients suffer intracranial hypertension and acute lung injury with hypoxemia. Since PEEP may improve hypoxemia but elevate ICP and decrease CPP, it is important to determine the influence of varying levels of PEEP on ICP and CPP. The aim of the study was to investigate the changes in ICP and CPP associated with different levels of PEEP. Twenty patients requiring ICP monitoring and mechanical ventilation were enrolled. Patients had severe head injury (n = 10), spontaneous intracerebral haemorrhage (n = 5), and subarachnoid haemorrhage (n = 5). PEEP was raised from 5 (basal) to 15 cm H2O in steps of 5 cm H2O. After at least 10 minutes of each new PEEP setting, ICP and CPP were measured. PEEP at 10 and 15 cm H2O produced a significant (p

Echocardiography is often requested in the management and diagnosis of hemodynamically unstable critically ill patients [1]. Transoesophageal echocardiography (TOE) is often considered the echocardiographic test of choice in the general ICU patient population. This is based on studies in which transthoracic echocardiography (TTE) commonly offered inadequate images [2]. The aim of this study is to assess the quality and quantity of images obtained in critically ill patients.

Vibration response imaging (VRI) is a novel technology that measures vibration energy generated from airflow to create a real-time structural and functional image of the respiration process. Since this new imaging technique can be performed quickly and non-invasively at the bedside, it offers potential as a real time noninvasive method of adjusting ventilatory therapy.

Different techniques to determine optimal PEEP setting in patients with ARDS have been suggested. The aim of our study was to evaluate assessment of static compliance of respiratory system in combination with estimated lung recruitment [1] for selection of PEEP setting with minimal Qs/Qt.

The interrelationships of compliance (CL), O2 transfer, CO2 excretion, and pulmonary circulation have not been explored in prematures with HMD. Using an esophageal balloon and pneumotach, CL was measured at intervals during titration of PEEP, together with arterial blood gases, in 7 prematures with HMD varying from 11h to 9d in age. As PEEP was varied stepwise upwards and downwards, an optimal value was found for CL. PaO2, and AaDO2. A 15 min. equilibration time was allowed at each PEEP setting, and the entire titration spanned 2-3 hrs. “Best PEEP” was different for CL, PaO2, and AaDO2, although best PaO2 and best AaDO2 were very similar. Interestingly, best PaO2 was at a significantly higher PEEP than best CL (mean 5 vs. 7.1cm H2O, P= < .05). PaCO2 rose at PEEPs of 6-9 in 4 patients, but was not limiting to “best PEEP.” The titration itself yielded an apparently beneficial “opening up” effect in 3 babies, in that repeat measurement of PaO2 and CL at the same PEEP showed improvement. Clinical estimations of PEEP were often not the same as recommended best PEEP, based on these titrations. In 3 cases PEEP was increased, in 2 it was decreased, and in 2 the previous setting was considered optimum. These data suggest that no single parameter defines “best PEEP,” but rather jt must be a judicious compromise.