Can ventilator settings reduce the negative effects of endotracheal suctioning? Investigations in a mechanical lung model.
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ABSTRACT:
SUBMITTER: Nakstad ER
PROVIDER: S-EPMC4924309 | biostudies-other | 2016
REPOSITORIES: biostudies-other
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Project description:AIMS:To create a low-cost ventilator that could be constructed with readily-available hospital equipment for use in emergency or low-resource settings. MAIN METHODS:The novel ventilator consists of an inspiratory limb composed of an elastic flow-inflating bag encased within a non-compliant outer sheath and an expiratory limb composed of a series of two, one-way bidirectional splitter valves derived from a self-inflating bag system. An Arduino Uno microcontroller controls a solenoid valve that can be programmed to open and close to produce a set respiratory rate and inspiratory time. Using an ASL 5000 Lung Simulator, we obtained flow, pressure, and volume waveforms at different lung compliances. KEY FINDINGS:At a static lung compliance of 50 mL/cm H2O and an airway resistance of 6 cm H2O/L/s, ventilated at a PIP and PEEP of 16 and 5 cm H2O, respectively, tidal volumes of approximately 540 mL were achieved. At a static lung compliance of 20 mL/cm H2O and an airway resistance of 6 cm H2O/L/s, ventilated at a PIP and PEEP of 38 and 15 cm H2O, respectively, tidal volumes of approximately 495 mL were achieved. SIGNIFICANCE:This novel ventilator is able to safely and reliably ventilate patients with a range of pulmonary disease in a simulated setting. Opportunities exist to utilize our ventilator in emergency situations and low-resource settings.
| S-EPMC7366115 | biostudies-literature
Project description:BackgroundThe current study investigates the effect of bronchoscopy-guided percutaneous dilatational tracheostomy (PDT) on the evolution of respiratory acidosis depending on endotracheal tube (ET) sizes. In addition, the impact of increasing tidal volumes during the intervention was investigated.MethodsTwo groups of ICU-patients undergoing bronchoscopy-guided PDT with varying tidal volumes and tube sizes were consecutively investigated: 6?ml/kg (N?=?29, mean age 57.4?±?14.5?years) and 12?ml/kg predicted body weight (N?=?34, mean age 59.5?±?12.8?years).ResultsThe mean intervention time during all procedures was 10?±?3?min. The combination of low tidal volumes and ETs of 7.5?mm internal diameter resulted in the most profound increase in PaCO2 (32.2?±?11.6?mmHg) and decrease in pH-value (-?0.18?±?0.05). In contrast, the combination of high tidal volumes and ETs of 8.5?mm internal diameter resulted in the least profound increase in PaCO2 (8.8?±?9.0?mmHg) and decrease of pH (-?0.05?±?0.04). The intervention-related increase in PaCO2 was significantly lower when using higher tidal volumes for larger ET: internal diameter 7.5, 8.0 and 8.5: P?>?0.05, =0.006 and?=?0.002, respectively. Transcutaneous PCO2 monitoring revealed steadily worsening hypercapnia during the intervention with a high correlation of 0.87 and a low bias of 0.7?±?9.4?mmHg according to the Bland-Altman analysis when compared to PaCO2 measurements.ConclusionsProfound respiratory acidosis following bronchoscopy-guided PDT evolves in a rapid and dynamic process. Increasing the tidal volume from 6 to 12?ml/kg PBW was capable of attenuating the evolution of respiratory acidosis, but this effect was only evident when using larger ETs.Trial registrationDRKS00011004 . Registered 20th September 2016.
| S-EPMC6689167 | biostudies-literature
Project description:PurposeDriving pressure (ΔP) and mechanical power (MP) may be important mediators of lung injury in acute respiratory distress syndrome (ARDS) however there is little evidence for strategies directed at lowering these parameters. We applied predictive modeling to estimate the effects of modifying ventilator parameters on ΔP and MP.Methods2,622 ARDS patients (Berlin criteria) from the Medical Information Mart for Intensive Care IV database (MIMIC-IV version1.0) admitted to the intensive care unit (ICU) at Beth Israel Deaconess Medical Center between 2008 and 2019 were included. Flexible confounding-adjusted regression models for time varying data were fit to estimate the effects of adjusting PEEP and tidal volume (VT) on ΔP, and adjusting VT and respiratory rate (f) on MP.ResultsReduction in VT reduced ΔP and MP, with more pronounced effect on MP with lower compliance. Strategies reducing f, consistently increased MP (when VT was adjusted to maintain consistent minute ventilation). Adjustment of PEEP yielded a U-shaped effect on ΔP.ConclusionsThis novel conditional modeling confirmed expected response patterns for ΔP, with the response to adjustments depending on patients' lung mechanics. Furthermore a VT -driven approach should be favored over a f -driven approach when aiming to reduce MP.
| S-EPMC9994280 | biostudies-literature
Project description:Motivated by a desire to understand pulmonary physiology, scientists have developed physiological lung models of varying complexity. However, pathophysiology and interactions between human lungs and ventilators, e.g., ventilator-induced lung injury (VILI), present challenges for modeling efforts. This is because the real-world pressure and volume signals may be too complex for simple models to capture, and while complex models tend not to be estimable with clinical data, limiting clinical utility. To address this gap, in this manuscript we developed a new damaged-informed lung ventilator (DILV) model. This approach relies on mathematizing ventilator pressure and volume waveforms, including lung physiology, mechanical ventilation, and their interaction. The model begins with nominal waveforms and adds limited, clinically relevant, hypothesis-driven features to the waveform corresponding to pulmonary pathophysiology, patient-ventilator interaction, and ventilator settings. The DILV model parameters uniquely and reliably recapitulate these features while having enough flexibility to reproduce commonly observed variability in clinical (human) and laboratory (mouse) waveform data. We evaluate the proof-in-principle capabilities of our modeling approach by estimating 399 breaths collected for differently damaged lungs for tightly controlled measurements in mice and uncontrolled human intensive care unit data in the absence and presence of ventilator dyssynchrony. The cumulative value of mean squares error for the DILV model is, on average, ≈12 times less than the single compartment lung model for all the waveforms considered. Moreover, changes in the estimated parameters correctly correlate with known measures of lung physiology, including lung compliance as a baseline evaluation. Our long-term goal is to use the DILV model for clinical monitoring and research studies by providing high fidelity estimates of lung state and sources of VILI with an end goal of improving management of VILI and acute respiratory distress syndrome.
| S-EPMC8517122 | biostudies-literature
Project description:BackgroundWhile patients with interstitial lung disease (ILD) may be particularly susceptible to ventilator-induced lung injury, ventilator strategies have not been studied in this group of patients.PurposesTo describe the clinical course and outcome of patients with ILD and acute respiratory failure in relation to ventilatory parameters.MethodsWe retrospectively identified a cohort of ventilated patients with ILD who had been admitted to five ICUs at a single institution. We analyzed demographic data, pulmonary function test results, severity of illness, and the parameters of continuous ventilation for the initial 24 h after admission to the ICU. Primary outcomes were survival to hospital discharge and 1-year survival.Main resultsOf 94 patients with ILD, 44 (47%) survived to hospital discharge and 39 (41%) were alive at 1 year. Nonsurvivors were less likely to be postoperative, had higher severity of illness, and were ventilated at higher airway pressures and lower tidal volumes. Step changes in positive end-expiratory pressure (PEEP) of > 10 cm H(2)O were attempted in 20 patients and resulted in an increase in plateau pressure (median difference, + 16 cm H(2)O; interquartile range [IQR], 9 to 24 cm H(2)O) and a decrease in respiratory system compliance (median difference, - 0.28 mL/kg/cm H(2)O; IQR, - 0.43 to - 0.13 mL/kg/cm H(2)O). The Cox proportional hazards model revealed that high PEEP (hazard ratio, 4.72; 95% confidence interval [CI], 2.06 to 11.15), acute physiology and chronic health evaluation (APACHE) III score predicted mortality (hazard ratio 1.33; 95% CI, 1.18 to 1.50), age (hazard ratio, 1.03; 95% CI, 1 to 1.05), and low Pao(2)/fraction of inspired oxygen ratio (hazard ratio, 0.96; 95% CI, 0.92 to 0.99) to be independent determinants of survival.ConclusionBoth severity of illness and high PEEP settings are associated with the decreased survival of patients with ILD who are receiving mechanical ventilation.
| S-EPMC4003484 | biostudies-literature
Project description:Hospital-acquired infections are a global health problem that threatens patients' treatment in intensive care units, causing thousands of deaths and a considerable increase in hospitalization costs. The endotracheal tube (ETT) is a medical device placed in the patient's trachea to assist breathing and delivering oxygen into the lungs. However, bacterial biofilms forming at the surface of the ETT and the development of multidrug-resistant bacteria are considered the primary causes of ventilator-associated pneumonia (VAP), a severe hospital-acquired infection for significant mortality. Under these circumstances, there has been a need to administrate antibiotics together. Although necessary, it has led to a rapid increase in bacterial resistance to antibiotics. Therefore, it becomes necessary to develop alternatives to prevent and combat these bacterial infections. One possibility is to turn the ETT itself into a bactericide. Some examples reported in the literature present drawbacks. To overcome those issues, we have designed a photosensitizer-containing ETT to be used in photodynamic inactivation (PDI) to avoid bacteria biofilm formation and prevent VAP occurrence during tracheal intubation. This work describes ETT's functionalization with curcumin photosensitizer, as well as its evaluation in PDI against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli A significant photoinactivation (up to 95%) against Gram-negative and Gram-positive bacteria was observed when curcumin-functionalized endotracheal (ETT-curc) was used. These remarkable results demonstrate this strategy's potential to combat hospital-acquired infections and contribute to fighting antimicrobial resistance.
| S-EPMC7502737 | biostudies-literature
Project description:Ventilator-associated pneumonia (VAP) is a common nosocomial infection in neonatal intensive care units with high morbidity and mortality. Bacterial biofilm in the endotracheal tube (ET) provides a notable and persistent source of pathogens that may cause VAP, and thus is important for VAP detection. However, during intubation microbial investigations in ET, samples are unavailable due to the infeasibility of collecting ET samples during intubation of neonates. It is therefore of great importance to find alternative sources of samples that can help identify the ET biofilm flora. In the present study, the microbial signatures of throat swabs and tracheal aspirates were compared with ET biofilm samples from VAP neonates using 16S ribosomal RNA gene polymerase chain reaction, denaturing gradient gel electrophoresis (DGGE), cloning and sequencing. Sequences were assigned to phylogenetic species using BLAST. Microbial diversity and richness among the three types of specimens were compared based on their DGGE fingerprints, and taxonomic characteristics based on the BLAST results. The microbial richness and diversity of ET biofilms were similar to tracheal aspirate yet significantly different from throat swab samples (P<0.05). Compared with ET biofilms, the overall constituent ratio of microflora was significantly different in throat swab and tracheal aspirate samples (P<0.05). However tracheal aspirate samples were useful for predicting Staphylococcus sp. in ET biofilms with a sensitivity of 85.7% and a specificity of 83.3%. The sensitivity for the combination of tracheal aspirate and throat swab samples to detect Staphylococcus sp. in ET biofilms was 100%. The detection of Pseudomonas sp. in throat swabs assisted its identification in ET biofilms (sensitivity 33.3% and specificity 100%). The results of the present study suggest that microbial investigations in throat swab and tracheal aspirate samples are beneficial for identifying the ET biofilm flora. There may therefore be clinical applications of using substituent samples to identify pathogens in ET biofilms for VAP surveillance among intubated neonates.
| S-EPMC5526163 | biostudies-literature
Project description:The interest in perioperative lung protective ventilation has been increasing. However, optimal management during one-lung ventilation (OLV) remains undetermined, which not only includes tidal volume (VT) and positive end-expiratory pressure (PEEP) but also inspired oxygen fraction (FIO2). We aimed to investigate current practice of intraoperative ventilation during OLV, and analyze whether the intraoperative ventilator settings are associated with postoperative pulmonary complications (PPCs) after thoracic surgery.We performed a prospective observational two-center study in Japan. Patients scheduled for thoracic surgery with OLV from April to October 2014 were eligible. We recorded ventilator settings (FIO2, VT, driving pressure (?P), and PEEP) and calculated the time-weighted average (TWA) of ventilator settings for the first 2 h of OLV. PPCs occurring within 7 days of thoracotomy were investigated. Associations between ventilator settings and the incidence of PPCs were examined by multivariate logistic regression.We analyzed perioperative information, including preoperative characteristics, ventilator settings, and details of surgery and anesthesia in 197 patients. Pressure control ventilation was utilized in most cases (92%). As an initial setting for OLV, an FIO2 of 1.0 was selected for more than 60% of all patients. Throughout OLV, the median TWA FIO2 of 0.8 (0.65-0.94), VT of 6.1 (5.3-7.0) ml/kg, ?P of 17 (15-20) cm H2O, and PEEP of 4 (4-5) cm H2O was applied. Incidence rate of PPCs was 25.9%, and FIO2 was independently associated with the occurrence of PPCs in multivariate logistic regression. The adjusted odds ratio per FIO2 increase of 0.1 was 1.30 (95% confidence interval: 1.04-1.65, P =?0.0195).High FIO2 was applied to the majority of patients during OLV, whereas low VT and slight degree of PEEP were commonly used in our survey. Our findings suggested that a higher FIO2 during OLV could be associated with increased incidence of PPCs.
| S-EPMC5785851 | biostudies-other
Project description:ObjectiveTo develop a simple, robust, safe and efficient invasive mechanical ventilator that can be used in remote areas of the world or war zones where the practical utility of more sophisticated equipment is limited by considerations of maintainability, availability of parts, transportation and/or cost.MethodsThe device implements the pressure-controlled continuous mandatory ventilation mode, complemented by a simple assist-control mode. Continuous positive airway pressure is also possible. The consumption of compressed gases is minimized by avoiding a continuous flow of oxygen or air. Respiratory rates and inspiration/expiration time ratios are electronically determined, and an apnea/power loss alarm is provided.ResultsThe pressure profiles were measured for a range of conditions and found to be adjustable within a ± 2.5cmH2O error margin and stable well within this range over a 41-hour period. Respiratory cycle timing parameters were precise within a few percentage points over the same period. The device was tested for durability for an equivalent period of four months. Chemical and biological tests failed to identify any contamination of the gas by volatile organic compounds or microorganisms. A ventilation test on a large animal, in comparison with a well established ventilator, showed that the animal could be adequately ventilated over a period of 60 minutes, without any noticeable negative aftereffects during the subsequent 24-hour period.ConclusionThis ventilator design may be viable, after further animal tests and formal approval by the competent authorities, for clinical application in the abovementioned atypical circumstances.
| S-EPMC9749093 | biostudies-literature
Project description:Ventilator-associated pneumonia (VAP) is a prevalent and costly nosocomial infection related to instrumentation of the airway with an endotracheal tube (ETT), enabling microaspiration of contaminated secretions. Modification of the ETT design to reduce microaspiration and/or biofilm formation may play an important role in VAP prevention. However, there is insufficient evidence to provide strong recommendations regarding the use of modified ETT and unaddressed safety concerns.We performed a pilot randomized controlled trial comparing two modified ETTs designed specifically to prevent VAP, with the standard ETT, to test the feasibility of and inform planning for a large, pivotal, randomized trial.This study was conducted with institutional review board approval under exception from informed consent. We randomized in a blinded fashion patients undergoing emergency endotracheal intubation both out of and in hospital to receive one of three different ETT types: (1) a polyurethane-cuffed tube (PUC-ETT), (2) a polyurethane-cuffed tube equipped with a port for continuous aspiration of subglottic secretions (PUC-CASS-ETT), or a (3) standard polyvinylchloride-cuffed tube (PVC-ETT). In addition to investigating feasibility and safety, the study coprimary end points were tracheal bacterial colonization reaching a cfu count >10(6) cfu per milliliter and the incidence of invasively diagnosed VAP.A total of 102 subjects were randomized and met the eligibility criteria. Randomization procedures performed well and integrity of blinding at randomization was maintained. The majority of intubations occurred in the hospital setting (n?=?77), and the remainder occurred out of hospital (n?=?25). Compared with the PVC-ETT, there were no significant differences in tracheal colonization for PUC-ETT (odds ratio [OR], 0.98; 95% confidence interval [CI], 0.31-3.09) or for PUC-CASS-ETT (OR, 1.26; 95% CI, 0.42-3.76). There were no differences in the risk of invasively diagnosed VAP (OR, 1.14; 95% CI, 0.21-6.08 for PUC-ETT; OR, 1.47; 95% CI, 0.30-7.10 for PUC-CASS-ETT), or of clinically diagnosed VAP by either clinical signs or chest radiograph criteria. We did not observe unexpected or serious adverse events related to the devices.A randomized trial of ETTs inserted during emergency intubation for the prevention of VAP is feasible and did not appear to carry heightened safety concerns. These preliminary data did not suggest different patterns of tracheal colonization or occurrence of VAP among the study groups. Clinical trial registered with www.clinicaltrials.gov (NCT01744483).
| S-EPMC4722846 | biostudies-literature