Telemedicine critical care availability and outcomes among mechanically ventilated patients

PURPOSE

Telemedicine Critical Care (TCC) improves adherence to evidence based protocols associated with improved mortality among patients receiving invasive mechanical ventilation (IMV). We sought to evaluate the relationship between hospital availability of TCC and outcomes among patients receiving IMV.

MATERIALS AND METHODS

We performed a cross-sectional study of 66,522 adults who received IMV for non-postoperative acute respiratory failure at 318 non-federal hospitals in New York, Massachusetts, Maryland, and Florida in 2018. Hospital-level TCC availability was ascertained from the 2018 American Hospital Association Annual Survey. The primary outcome was in-hospital mortality. Secondary outcomes included the composite of tracheostomy or reintubation and duration of IMV. We used two-level hierarchical multivariable regression models to investigate the association between TCC availability and outcomes.

RESULTS

20,270 (30.5%) patients were admitted into 89 TCC-available hospitals. There was no difference between TCC and non-TCC-available hospitals in mortality (odds ratio [OR] 0.94, 99% confidence interval [CI] 0.84-1.05), composite of tracheostomy or reintubation (OR 0.95 [0.82-1.11], or duration of IMV (OR 0.95 [0.83-1.09]). There was no difference in outcomes among the subgroup of patients with acute respiratory distress syndrome.

CONCLUSIONS

Hospital TCC availability was not associated with improved outcomes among patients receiving IMV.

Ventilator hyperinflation associated with flow bias optimization in the bronchial hygiene of mechanically ventilated patients

BACKGROUND

Ventilation configurations are of great clinical importance for adequate outcomes in mechanically ventilated patients, and they may even be used as specific physical therapy techniques.

OBJECTIVES

To compare the effectiveness of lung hyperinflation through mechanical ventilation (HMV) with HMV plus flow bias optimization regarding respiratory mechanics, hemodynamics, and volume of secretion.

METHODS

Patients mechanically ventilated > 24 h were included in this randomized crossover clinical trial. The following techniques were applied: HMV alone (control group) and HMV plus flow bias optimization (intervention group).

RESULTS

The 20 included patients underwent both techniques, totaling 40 collections. A total of 52 % were women, the mean age was 60.8 (SD, 15.7) years, and the mean mechanical ventilation time was 4.3 (SD, 3.0) days. The main cause of mechanical ventilation was sepsis (44 %). Expiratory flow bias in optimized HMV was higher. than conventional HMV (p < 0.001). The volume of tracheal secretions collected was higher during optimized than conventional HMV. (p = 0.012). Significant differences in peak flow occurred at the beginning of the technique and a there was a significant decrease in respiratory system resistance immediately and 30 min after applying the technique in the intervention group.

CONCLUSIONS

The volume of tracheal secretions collected was higher during optimized HMV, and, HMV with flow bias optimization resulted in lower respiratory system resistance and flow peaks and produced expiratory flow bias.

Steroids and myocardial infarction: Investigating safety and short-term mortality in critical post-myocardial infarction patients

BACKGROUND

Conventionally, in the pre-percutaneous intervention era, free wall rupture is reported to be a major concern for using steroids in myocardial infarction (MI) patients. Therefore, the aim of this study was to evaluate the safety of the use of steroids in critically ill post-MI patients in terms of hospital course and short-term (up to 180-day) mortality.

METHODS

We included patients admitted to CCU diagnosed with MI, undergone revascularization, critically ill, and requiring mechanical ventilator (MV) support. The hospital course and short-term (up to 180-day) mortality were independently compared between steroid and non-steroid cohorts and propensity-matched non-steroid cohorts.

RESULTS

A total of 312 patients were included, out of which steroids were used in 93(29.8%) patients during their management. On periodic bedside echocardiography, no free wall rupture was documented in the steroid or non-steroid cohort. When compared steroids with a propensity-matched non-steroid cohort, MV duration >24 h was 66.7% vs. 59.1%; p = 0.288, major bleeding was 6.5% vs. 3.2%; p = 0.305, need for renal replacement therapy was 9.7% vs. 8.6%; p = 0.799, in-hospital mortality was 35.5% vs. 23.7%; p = 0.077, and 180-day mortality was 48.4% vs. 41.9%; p = 0.377, respectively. The hazard ratio was 1.22 [95% CI: 0.80 to 1.88] compared to the propensity-matched non-steroid cohort. The ejection fraction (%) was found to be the independent predictor of 180-day mortality with an adjusted odds ratio of 0.92 [95% CI: 0.86 to 0.98].

CONCLUSIONS

In conclusion, using steroids is safe in post-MI patients with no significant increase in short-term mortality risk.

Ventilator-associated pneumonia by Weeksella virosa: case report

BACKGROUND

Weeksella virosa pneumonia is an infection that has been described as a healthcare-associated infection. This is a rare gram-negative anaerobic bacterium associated with the use of mechanical ventilation for a long period of time and is more frequent in immunosuppressed patients. This is the first case reported in the state of Veracruz and the second in Mexico.

CASE PRESENTATION

We present the case of a 64-year-old female from Veracruz, Mexico who developed an infectious process in the right pelvic limb after a transcatheter aortic valve replacement procedure and subsequently developed sudden cardiorespiratory arrest requiring mechanical ventilation, with subsequent imaging studies demonstrating a pneumonic process associated with a nosocomial infection.

DISCUSSION AND CONCLUSIONS

We should take into consideration that this pathogen affects not only adults with multiple comorbidities but also children with renal, hepatic, or oncological pathologies, as well as immunocompromised patients, who should be considered high-risk populations for W. virosa infection.

Ventilator support in the pretransplant period predisposes early graft failure after deceased donor liver transplantation

Purpose

Deceased donor liver transplantation (DDLT) recipients in Korea are generally sicker due to an increasing organ shortage. In the present study, the risk factors for early 30-day liver graft failure after DDLT were identified.

Methods

From August 2017 to February 2021, 265 adult DDLTs were performed. The characteristics of patients with and without 30-day graft failure were compared.

Results

Liver graft failure occurred in 11 patients (17.7%) after DDLT. Baseline and perioperative characteristics of donors and recipients were not statistically significantly different between the 2 groups. The cumulative graft and overall survival rates at 6 months were 83.9% and 88.7%, respectively. Multivariate analysis showed ventilator support in the pretransplant period was a predisposing factor for 30-day graft failure after DDLT.

Conclusion

Present study indicates that cautious decision is required when allocating DDLT in critically ill patients on mechanical ventilatory support.

Effect of Oral Caffeine on Weaning from Mechanical Ventilation in Intubated ICU Patients

Background

The role of caffeine as a brain stimulant in improving the respiratory characteristics of patients under mechanical ventilation is unclear. This study aimed at determining the effect of oral caffeine in helping to release (Liberation) from the ventilator in intubated patients under mechanical ventilation admitted to the intensive care unit.

Materials and Methods

General ICU patients with more than 48 hours of dependency on a ventilator were randomly divided into two groups. The intervention group received 200mg caffeine tablets twice a day through a gastric tube, while the control group received a placebo of the same amount. Every day, patients were assessed for the likelihood of being disconnected from the device. If their clinical condition was deemed suitable, the device mode was switched to spontaneous, and their Rapid Shallow Breathing Index (RSBI) was calculated. Based on this information, a decision was made regarding whether to proceed with weaning.

Results

Caffeine use in ICU patients significantly reduced the airway resistance index of patients (P <0.05). However, although this drug reduced the length of hospital stay in the ICU and the duration of intubation of patients, these changes were not statistically significant (P> 0.05).

Conclusion

Caffeine may improve respiratory status and reduce the duration of intubation and hospitalization in the ICU.

Kidney and lung crosstalk during critical illness: large-scale cohort study

BACKGROUND

The relationship between the lung and kidney investigated in animal and clinical models has demonstrated substantial crosstalk. We aimed to evaluate the association between single vs. concurrent AKI and ARDS and its impact on patient outcomes. Secondly, we aimed to assess whether the order of appearance of these pathologies affected patient outcomes in patients with both diseases.

METHODS

This single-center retrospective cohort study included adult patients admitted to the ICU from January 1, 2007 through May 1, 2018 (n = 76,988). Baseline characteristics and outcomes were compared among patients without ARDS or AKI and those with one or both ARDS and AKI. We also assessed outcomes across the order of appearance of these diseases among patients with both AKI and ARDS.

RESULTS

We enrolled 76,988 unique patients in the final analysis: 47,043 patients with neither AKI nor ARDS, 491 patients with ARDS alone, 27,928 patients with AKI alone, and 1,526 patients with both ARDS and AKI. Patients with both ARDS and AKI had higher ICU (21.2%) and hospital (28.4%) mortality compared to patients with ARDS alone (9.0% ICU mortality, 14.0% hospital mortality) or AKI alone (4.4% ICU mortality, 8.4% hospital mortality) (p < 0.001). These findings remained unchanged after adjusting for illness severity and comorbidities. Of the 1136 patients with both AKI and ARDS, 136 (12%) developed AKI first, 303 (27%) ARDS first, and 697 (61%) had simultaneous diseases. Patients who developed ARDS after AKI had significantly increased ICU (29.4%) and hospital (36.8%) mortality compared to patients who developed AKI after ARDS (13.9% ICU mortality, 21.5% hospital mortality) (p < 0.001).

CONCLUSIONS

The combination of AKI and ARDS leads to worse outcomes, including longer hospital and ICU lengths of stay, higher mortality, longer kidney replacement therapy, and longer ventilation requirements than in patients with AKI or ARDS alone. Among patients with both diagnoses, those who developed ARDS after AKI had the highest mortality.

Changes in Maximum Tongue Pressure and Postoperative Dysphagia in Mechanically Ventilated Patients after Cardiovascular Surgery

Background

There is no objective quantitative parameter for dysphagia, and the relationship between changes in maximum tongue pressure values and dysphagia is unknown. This study aimed to determine whether there is a difference in the change in maximal tongue pressure after extubating patients who were ventilated after cardiovascular surgery, with or without dysphagia.

Materials and methods

Adult patients who underwent mechanical ventilation via endotracheal intubation following cardiovascular surgery were included. Tongue pressure was measured before cardiovascular surgery and at 6 hours; 3 and 7 days after extubation. Dysphagia was confirmed by the functional oral intake scale (FOIS) on day 7 after extubation; an FOIS level above or equal to 6 was considered "dysphagia-negative."

Results

Of 68 patients, 15 (22.1%) were in the dysphagia-positive group, which significantly showed a history of diabetes mellitus, prolonged mechanical ventilation, and postextubation hospitalization. Additionally, the postoperative C-reactive protein level was significantly higher in the dysphagia-positive group than in the dysphagia-negative group. Maximum tongue pressure was significantly lower in the dysphagia-positive group at 3 and 7 days postextubation. Using a cutoff value of 27.6 kPa in a receiver operating characteristic (ROC) curve for maximum tongue pressure at 3 days after extubation, the area under the curve (AUC) was 0.82, sensitivity was 84.9%, and specificity was 84.2%.

Conclusion

Tongue pressure at 3 days after extubation is significantly lower in patients with dysphagia after cardiovascular surgery than in patients without dysphagia. If the maximum tongue pressure value is below 27.6 kPa on the third day following extubation, oral intake should be performed with caution.

How to cite this article

Yamada T, Ochiai R, Kotake Y. Changes in Maximum Tongue Pressure and Postoperative Dysphagia in Mechanically Ventilated Patients after Cardiovascular Surgery. Indian J Crit Care Med 2022;26(12):1253-1258.

Modeling and control of an invasive mechanical ventilation system using the active disturbances rejection control structure

We propose a mandatory invasive mechanical ventilator prototype for severe COVID-19 patients with volume and pressure control operation modes. This system comprises basic pneumatic elements and sensors. Its performance is similar to commercial equipment, and it presents robustness to external disturbances and parametric uncertainties. To develop a control strategy, we propose a mathematical model with a variable structure that incorporates the dead zone phenomenon of the proportional valve, and considers external disturbances and parametric uncertainties. Based on this model, we propose a global control strategy that is based on pressure and flow regulation controllers, which use the active disturbances rejection control structure (ADRC). In this strategy, we propose robust state observers to estimate disturbances and the signals necessary for implementing the controllers. We illustrate the performance of the prototype and the control strategy through numerical simulations and experiments. We also compare its performance with PID controllers. These results corroborate its effectiveness and the possibility of its application in invasive mechanical ventilators with a simple structure, which can significantly help critical care of COVID-19 inpatients.

NISHASH: A reasonable cost-effective mechanical ventilator for COVID affected patients in Bangladesh

COVID-19 has elapsed all over the world with massive losses which indicate the lack of availability of medical equipment during the pandemic such as a ventilator. This is exemplified by the densely populated country Bangladesh who unable to maintain COVID-affected people because of the ventilator. Due to the higher price, unavailability, and manufacturing defection, most medical are unable to purchase this ventilator which causes terrible death for a respiratory problem. Of these cases, this paper represents a way to escape this problem and proposed a mechanical ventilator named “NISHASH” which will help to anticipate COVID affected people and higher price of the ventilator. Through the electromechanical instruments, a prototype lightweight easily moveable where preciously it automatically controls with digital feedback system ventilator which fulfills oxygen flow based on patient requirement are developed with different selection mode. The aim was to design and develop inexpensively automated easy to build to minimize the extreme shortage of the ventilator in Bangladesh. In this model of a mechanical ventilator, the cost is less than $90 where components are available all over the world.

Clinical predictors and electrodiagnostic characteristics in patients with Guillain-Barré syndrome with respiratory failure: a retrospective, matched case-control study

BACKGROUND

Respiratory failure is a common complication of Guillain-Barré syndrome (GBS). This study aimed to determine the clinical predictors and electrodiagnostic (EDx) characteristics in patients with Guillain-Barré syndrome (GBS) with respiratory failure.

METHODS

The retrospective study included 29 confirmed GBS cases with respiratory failure and age- (±5 years) and sex-matched controls (1:1). The dependent t-test and McNemar-Bowker test were used to analyse the continuous and categorical data, respectively. In addition, a multiple logistic regression analysis was used to analyse the predictive factors for respiratory failure.

RESULTS

Among both cases and controls, the majority were male (72.4%), and the average age was 50.9 years. The data showed that patients with respiratory failure had higher GBS disability scores, lower motor power (≤3) of the hip flexors and ankle dorsiflexors, and experienced facial and bulbar palsy. In the multivariate analysis, the significant predictive factors were bulbar palsy (AOR 10.4 [95% CI [2.6-41.4]) and motor power of hip flexors ≤ 3 (AOR 31.4 [95% CI [3.1-314.5]). Patients with respiratory failure had lower compound muscle action potential amplitude of the ulnar and tibial nerves. The median, ulnar, and tibial nerve conduction studies were more likely to reflect inexcitability. The GBS subtypes in GBS patients with and without respiratory failure were not significantly different.

CONCLUSIONS

Bulbar palsy and motor power of the hip flexors ≤ 3 were significant predictors for respiratory failure. The GBS subtypes in patients with and without respiratory failure were not significantly different.

A new COVID-19 intubation prediction strategy using an intelligent feature selection and K-NN method

Background

Predicting severe respiratory failure due to COVID-19 can help triage patients to higher levels of care, resource allocation and decrease morbidity and mortality. The need for this research derives from the increasing demand for innovative technologies to overcome complex data analysis and decision-making tasks in critical care units. Hence the aim of our paper is to present a new algorithm for selecting the best features from the dataset and developing Machine Learning(ML) based models to predict the intubation risk of hospitalized COVID-19 patients.

Methods

In this retrospective single-center study, the data of 1225 COVID-19 patients from February 9, 2020, to July 20, 2021, were analyzed by several ML algorithms which included, Decision Tree(DT), Support Vector Machine (SVM), Multilayer perceptron (MLP), and K-Nearest Neighbors(K-NN). First, the most important predictors were identified using the Horse herd Optimization Algorithm (HOA). Then, by comparing the ML algorithms' performance using some evaluation criteria, the best performing one was identified.

Results

Predictive models were trained using 12 validated features. Also, it found that proposed DT-based predictive model enables a reasonable level of accuracy (=93%) in predicting the risk of intubation among hospitalized COVID-19 patients.

Conclusions

The experimental results demonstrate the effectiveness of the proposed meta-heuristic feature selection technique in combining with DT model in predicting intubation risk for hospitalized patients with COVID-19. The proposed model have the potential to inform frontline clinicians with quantitative and non-invasive tool to assess illness severity and to identify high risk patients.

Pressure-flow breath representation eases asynchrony identification in mechanically ventilated patients

Breathing asynchronies are mismatches between the requests of mechanically ventilated subjects and the support provided by mechanical ventilators. The most widespread technique in identifying these pathological conditions is the visual analysis of the intra-tracheal pressure and flow time-trends. This work considers a recently introduced pressure-flow representation technique and investigates whether it can help nurses in the early detection of anomalies that can represent asynchronies. Twenty subjects—ten Intensive Care Unit (ICU) nurses and ten persons inexperienced in medical practice—were asked to find asynchronies in 200 breaths pre-labeled by three experts. The new representation increases significantly the detection capability of the subjects—average sensitivity soared from 0.622 to 0.905—while decreasing the classification time—from 1107.0 to 567.1 s on average—at the price of a not statistically significant rise in the number of wrong identifications—specificity average descended from 0.589 to 0.52. Moreover, the differences in experience between the nurse group and the inexperienced group do not affect the sensitivity, specificity, or classification times. The pressure-flow diagram significantly increases sensitivity and decreases the response time of early asynchrony detection performed by nurses. Moreover, the data suggest that operator experience does not affect the identification results. This outcome leads us to believe that, in emergency contexts with a shortage of nurses, intensive care nurses can be supplemented, for the sole identification of possible respiratory asynchronies, by inexperienced staff.

Mechanical Power: A New Concept in Mechanical Ventilation

Mechanical ventilation is a potentially life-saving therapy for patients with acute lung injury, but the ventilator itself may cause lung injury. Ventilator-induced lung injury (VILI) is sometimes an unfortunate consequence of mechanical ventilation. It is not clear however how best to minimize VILI through adjustment of various parameters including tidal volume, plateau pressure, driving pressure, and positive end expiratory pressure (PEEP). No single parameter provides a clear indication for onset of lung injury attributable exclusively to the ventilator. There is currently interest in quantifying how static and dynamic parameters contribute to VILI. One concept that has emerged is the consideration of the amount of energy transferred from the ventilator to the respiratory system per unit time, which can be quantified as mechanical power. This review article reports on recent literature in this emerging field and future roles for mechanical power assessments in prospective studies.

Design and simulation of mechanical ventilators

During this period of COVID-19 pandemic, the lack of medical equipment (like ventilators) leads to complications arising in the medical field. A low-cost ventilator seems to be an alternative substitute to fill the lacking. This paper presents a numerical analysis for predicting the delivered parameters of a low-cost mechanical ventilator. Based on several manufactured mechanical ventilators, two proposed designs are investigated in this study. Fluid-structure interaction (FSI) analysis is used for solving any problems with the first design, and computational fluid dynamic (CFD) analysis with moving boundary is used for solving any issues with the second design. For this purpose, ANSYS Workbench platform is used to solve the set of equations. The results showed that the Ambu-bag-based mechanical ventilator exhibited difficulties in controlling ventilation variables, which certainly will cause serious health problems such as barotrauma. The mechanical ventilator based on piston-cylinder is more satisfactory with regards to delivered parameters to the patient. The ways to obtain pressure control mode (PCM) and volume control mode (VCM) are identified. Finally, the ventilator output is highly affected by inlet flow, length of the cylinder, and piston diameter.

Design and simulation of AI-based low-cost mechanical ventilator: An approach

In this situation of COVID 19, many people are being exposed to coronavirus, resulting in difficulty in breathing and a drop in oxygen percentage of blood. A mechanical ventilator is playing a vital role in tackling this situation but the ventilation process is neither readily available nor affordable. The idea behind this work is to propose a simplified design of a mechanical ventilator to reduce the cost and automate the Mechanical ventilation process. The simplified design, it's working, and required components are elaborated in this paper. The simulation of the proposed design is made in MATLAB/Simulink platform which is also discussed below. Taking into account the work done in the area of cost reduction of the mechanical ventilation process, the mechanical ventilator with a simplified design comprising of compressed air and oxygen source is being considered. The parameters considered for mechanical ventilation are positive end-expiratory pressure (PEEP), pressure wave, respiratory rate (RR), tidal volume, etc. These parameters of oxygen and air mixture are to be controlled with the help of electronic devices which are pressure regulator, solenoid valve, flow sensor, proportional valve, microprocessor, etc depending upon the condition of patient and type of disease. Simulation results are promising and precise which allows the study on ventilator model without jeopardizing the life of human subjects as in clinical approach and hides the complexity of computational models from the user. Furthermore, advancements in this model are done by the machine learning approach.

Cost Effectiveness of Ceftolozane/Tazobactam Compared with Meropenem for the Treatment of Patients with Ventilated Hospital-Acquired Bacterial Pneumonia and Ventilator-Associated Bacterial Pneumonia

Introduction

The clinical efficacy and safety of ceftolozane/tazobactam for the treatment of ventilated hospital-acquired bacterial pneumonia (vHABP) and ventilator-associated bacterial pneumonia (VABP) has been demonstrated in the phase III randomised controlled trial ASPECT-NP. However, there are no published data on the cost-effectiveness of ceftolozane/tazobactam for vHABP/VABP. These nosocomial infections are associated with high rates of morbidity and mortality, and are increasingly complicated by growing rates of resistance and the inappropriate use of antimicrobials. This study is to assess the cost-effectiveness of ceftolozane/tazobactam compared with meropenem for the treatment of vHABP/VABP in a US hospital setting.

Methods

A short-term decision tree followed by a long-term Markov model was developed to estimate lifetime costs and quality-adjusted life-years associated with ceftolozane/tazobactam and meropenem in the treatment of patients with vHABP/VABP. Pathogen susceptibility and clinical efficacy were informed by the Program to Assess Ceftolozane/Tazobactam Susceptibility (PACTS) database and ASPECT-NP, respectively. A US healthcare sector perspective was adopted, capturing direct costs borne by third-party payers or integrated health systems, and direct health effects for patients.

Results

In the confirmed treatment setting (post-susceptibility results), the incremental cost-effectiveness ratio for ceftolozane/tazobactam compared to meropenem was US$12,126 per quality-adjusted life-year (QALY); this reduced when used in the early treatment setting (before susceptibility results) at $4775/QALY.

Conclusion

Ceftolozane/tazobactam represents a highly cost-effective treatment option for patients with vHABP/VABP versus meropenem when used in either the confirmed or early treatment setting; with increased cost-effectiveness shown in the early setting.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-021-00436-4.

Concept and Prelimnary Design of an Economical Bag Valve Mask Compressor as a Prototype for Simple Ventilator During COVID-19

The pandemic of COVID 19 has taken a massive toll of lives since its outbreak. Throughout the world with a large number of people being affected by covid 19, the need for the ventilators has risen. However, there is disproportionate ratio of demand versus supply of ventilators due to the menace caused by Covid 19 which has become unmanageable. This paper describes the design of the low cost portable mechanical bag valve mask compressor which could serve as a preliminary ventilator for the patients needing ventilator support in COVID 19. This prototype ventilator delivers breaths by compressing a conventional bag-valve mask (BVM) with a motor, eliminating the need for a human operator for the BVM. It is driven by a wind shield wiper electric motor powered by a 12 V battery. Additionally it can be used to deliver oxygen through either Laryngeal mask or compact face masks or nasopharyngeal airways where intubation is awaited in early breathlessness. Future additions for our prototype ventilator will include a controllable inspiration to expiration time ratio, a pressure relief valve, PEEP capabilities and an LCD screen. With a prototyping cost of only $150, the concept of BVM compressor is a low-cost, low-power portable ventilator technology that will provide essential ventilator features at a fraction of the cost of existing technology.

Historical development of the anesthetic machine: from Morton to the integration of the mechanical ventilator

The first anesthetic machines appeared following their public demonstration by Morton in 1846. These initial devices were simple inhalers based on the evaporation of the anesthetic agent. Their main problem was the loss of effectiveness with cooling. More complex inhalers were subsequently developed, in which the main difference was the possibility to provide more than one agent. Moreover, the concentration of the inhaled anesthetic was regulated for greater efficiency. At the beginning of the twentieth century, gas machines emerged, allowing the application of an anesthetic flow independent of the patient’s inspiratory effort. These machines incorporated technological advances such as flow meters, carbon dioxide absorption systems and fine adjustment vaporizers. In this period, in the field of thoracic surgery, intraoperative artificial ventilation began to be employed, which helped overcome the problem of pneumothorax associated with open pleura by applying positive pressure. From the 1930s, the gas machines were fitted with a ventilator, and by the 1950s this had become a basic component of the anesthesia system. Later still, in the 1980s, alarm and monitoring systems were incorporated, giving rise to the current generation of workstations.

The effect of oropharyngeal aspiration before position change on reducing the incidence of ventilator- associated pneumonia

The aim of this study was to investigate the effect of oropharyngeal aspiration on ventilator-associated pneumonia (VAP) incidence just prior to changing patient position. This randomized controlled experimental study was conducted between July 2015 and April 2019 in anesthesiology and reanimation of intensive care unit (ICU). The patients of experimental group underwent oropharyngeal aspiration under surgical aseptic conditions before each position change. Patients of the control group received oropharyngeal aspiration only as needed. The mean age of the patients was 62.87 ± 17.33 years. The mean and median duration of stay in the ICU were 27.28 ± 30.69 and 18.00 days respectively. The mean and median of duration of the mechanical ventilation support were 26.72 ± 30.65 and 18.00 (min 4; max 168) days respectively. Thirty percent of the patients were VAP. The mean duration of VAP development was 7.50 ± 5.07 days. The rate of VAP development was 11.23/1000 mechanical ventilator days. Only 8.3% of the experimental group patients developed VAP; 91.7% of the control group patients developed VAP. The VAP rate in the control group was 16.82/1000 mechanical ventilator days and the VAP rate in the experimental group was 2.41/1000 mechanical ventilator days. Most VAP agents were multidrug resistant. Distribution of isolated microorganisms was as Acinetobacter baumannii, Pseudomonas aeruginosa, Corynebacterium striatum, Staphylococcus aureus, Providencia stuartii, Serratia marcescens, Stenotrophomonas maltophilia, and Aspergillus flavus. In our study, it was concluded that oropharyngeal aspiration performed prior to patient position change prevented the development of VAP.

ATMO-vent: An adapted breathing atmosphere for COVID-19 patients

The ongoing worldwide pandemic of coronavirus disease 2019 (COVID-19), has been one of the most significant challenges to humankind in centuries. The extremely contagious nature of the SARS-CoV-2 virus has put forth an immense pressure on the health sector. In order to mitigate the stress on the healthcare systems especially to battle the crisis of mechanical ventilators, we have designed a modular, and robust DIY ventilator, ATMO-Vent (Atmospheric Mixture Optimization Ventilator) which can be fully mounted within two days by two operators. The ATMO-Vent has been designed using low-cost, robust, Commercial Off The Shelf (COTS) components, with many features comparable to a full-fledged ventilator. ATMO-Vent has been designed based on the United Kingdom Medicines & Healthcare products Regulatory Agency (UK-MHRA) guidelines for Rapidly Manufactured Ventilator System (RMVS), yet is scalable to the specific requirements of different countries. ATMO-Vent is capable of adjusting the Fraction of Inspiratory Oxygen (FiO₂) levels, Tidal Volume (TV), frequency of breaths, Inspiratory/Expiratory ratio (I/E), Peak Inspiratory Pressure (PIP) and Positive End-Expiratory Pressure (PEEP). ATMO-Vent can operate in two modes - Continuous Mandatory Ventilation (CMV) using Volume-Controlled Ventilation (VCV) and in Assisted Control (AC) mode with pressure triggered by the patient. ATMO-Vent has undergone rigorous testing and qualifies under Class B Electric and Magnetic Compatibility (EMC) requirements of EN 55,011 CISPR 11 standards.

Can Open Source Hardware Mechanical Ventilator (OSH-MVs) initiatives help cope with the COVID-19 health crisis? Taxonomy and state of the art

The field of Open Source Hardware Mechanical Ventilators (OSH-MVs) has seen a steep rise of contributions during the 2020 COVID-19 pandemic. As predictions showed that the number of patients would exceed current supply of hospital-grade ventilators, a number of formal (academia, the industry and governments) and informal (fablabs and startups) entities raced to develop cheap, easy-to-fabricate mechanical ventilators. The presence of actors with very diverse modus operandi as well as the speed at which the field has grown, led to a fragmented design space characterized by a lack of clear design patterns, projects not meeting the minimum functional requirements or showing little-to-no innovation; but also valid alternatives to hospital-grade devices. In this paper we provide a taxonomic system to help researchers with no background in biomedical engineering to read, understand and contribute to the OSH-MV field. The taxonomy is composed of ten properties that are read through the lenses of three reflection criteria: buildability, adoptability and scalability. We applied the taxonomy to the analysis of seventeen OSH-MV projects, which are representative of the current landscape of possibilities available for COVID-19 patients. We discuss the different design choices adopted by each project highlighting strengths and weaknesses and we suggest possible directions for the development of the OSH-MV field.

Mechanical ventilator as a shared resource for the COVID-19 pandemic

COVID-19, the causative agent of which is a new type of coronavirus called SARS-CoV-2, has caused the most severe pandemic in the last 100 years. The condition is mainly respiratory, and up to 5% of patients develop critical illness, a situation that has put enormous pressure on the health systems of affected countries. A high demand for care has mainly been observed in intensive care units and critical care resources, which is why the need to redistribute resources in critical medicine emerged, with an emphasis on distributive justice, which establishes the provision of care to the largest number of people and saving the largest number of lives. One principle lies in allocating resources to patients with higher life expectancy. Mechanical ventilator has been assumed to be an indivisible asset; however, simultaneous mechanical ventilation to more than one patient with COVID-19 is technically possible. Ventilator sharing is not without risks, but the principles of beneficence, non-maleficence and justice prevail. According to distributive justice, being a divisible resource, mechanical ventilator can be shared; however, we should ask ourselves if this action is ethically correct.

COVID-19 and respiratory support devices

There are significant logistical challenges to providing respiratory support devices, beyond simple oxygen flow, when centres run out of supplies or do not have these devices at all, such as in low resource settings. At the peak of the COVID-19 crisis, it was extremely difficult to import medical equipment and supplies, because most countries prohibited the medical industry from selling outside of their own countries. As a consequence, engineering teams worldwide volunteered to develop emergency devices, and medical experts in mechanical ventilation helped to guide the design and evaluation of prototypes. Although regulations vary among countries, given the emergency situation, some Regulatory Agencies facilitated expedited procedures. However, laboratory and animal model testing are crucial to minimize the potential risk for patients when treated with a device that may worsen clinical outcome if poorly designed or misused.

An effective pressure-flow characterization of respiratory asynchronies in mechanical ventilation

Ineffective effort during expiration (IEE) occurs when there is a mismatch between the demand of a mechanically ventilated patient and the support delivered by a Mechanical ventilator during the expiration. This work presents a pressure-flow characterization for respiratory asynchronies and validates a machine-learning method, based on the presented characterization, to identify IEEs. 1500 breaths produced by 8 mechanically-ventilated patients were considered: 500 of them were included into the training set and the remaining 1000 into the test set. Each of them was evaluated by 3 experts and classified as either normal, artefact, or containing inspiratory, expiratory, or cycling-off asynchronies. A software implementing the proposed method was trained by using the experts' evaluations of the training set and used to identify IEEs in the test set. The outcomes were compared with a consensus of three expert evaluations. The software classified IEEs with sensitivity 0.904, specificity 0.995, accuracy 0.983, positive and negative predictive value 0.963 and 0.986, respectively. The Cohen's kappa is 0.983 (with 95% confidence interval (CI): [0.884, 0.962]). The pressure-flow characterization of respiratory cycles and the monitoring technique proposed in this work automatically identified IEEs in real-time in close agreement with the experts.

A Phase II randomized controlled trial for lung and diaphragm protective ventilation (Real-time Effort Driven VENTilator management)

Lung Protective Mechanical Ventilation (MV) of critically ill adults and children is lifesaving but it may decrease diaphragm contraction and promote Ventilator Induced Diaphragm Dysfunction (VIDD). An ideal MV strategy would balance lung and diaphragm protection. Building off a Phase I pilot study, we are conducting a Phase II controlled clinical trial that seeks to understand the evolution of VIDD in critically ill children and test whether a novel computer-based approach (Real-time Effort Driven ventilator management (REDvent)) can balance lung and diaphragm protective ventilation to reduce time on MV. REDvent systematically adjusts PEEP, FiO₂, inspiratory pressure, tidal volume and rate, and uses real-time measures from esophageal manometry to target normal levels of patient effort of breathing. This trial targets 276 children with pulmonary parenchymal disease. Patients are randomized to REDvent vs. usual care for the acute phase of MV (intubation to first Spontaneous Breathing Trial (SBT)). Patients in either group who fail their first SBT will be randomized to REDvent vs usual care for weaning phase management (interval from first SBT to passing SBT). The primary clinical outcome is length of weaning, with several mechanistic outcomes. Upon completion, this study will provide important information on the pathogenesis and timing of VIDD during MV in children and whether this computerized protocol targeting lung and diaphragm protection can lead to improvement in intermediate clinical outcomes. This will form the basis for a larger, Phase III multi-center study, powered for key clinical outcomes such as 28-day ventilator free days. Clinical Trials Registration: NCT03266016.

Evolving concepts for safer ventilation

Our current understanding of protective measures for avoiding ventilator-induced lung injury (VILI) has evolved from targeting low tidal volumes to lowering plateau and driving pressure. Even when pressures across the lung are reliably estimated, however, pressures alone cannot accurately gauge the injury risk; apart from flow rate, inspired oxygen fraction, and currently unmeasurable features of the mechanical microenvironment such as geometry, structural fragility, and vascular perfusion, the frequency with which high-risk tidal cycles are applied must help determine the intensity of potentially damaging energy application. Recognition of a strain threshold for damage by transpulmonary pressure, coupled with considerations of total energy load and strain intensity, has helped shape the unifying concept of VILI generation dependent upon the power transferred from the ventilator to the injured lungs. Currently, under-recognized contributors to the injury process must be addressed to minimize the risk imposed by ventilatory support.

Better airway resistance reduction profile in intubated COPD patients by personalized bronchodilator dosing: A pilot randomized control trial

INTRODUCTION

The optimal dose of inhaled metered-dose bronchodilators for intubated patients with chronic obstructive pulmonary disease (COPD) is unknown. In this study, we proposed a bronchodilator dosing schedule based on an individual's airway resistance (R_aw) and tested its efficacy in reducing R_aw.

METHODS

A total of 51 newly admitted patients with invasively ventilated COPD were randomly assigned to receive personalized or fixed bronchodilator dosing. Personal target R_aw was defined by measuring each individual's R_aw after maximal pharmacologic bronchodilatation. Thereafter, R_aw was measured every 8 h until the 28th day. Patients in the fixed-dosing group received only predetermined doses. Additional doses of bronchodilators were given to patients in the personalized-dosing group when the measured R_aw exceeded their target R_aw.

RESULTS

The median daily doses of salmeterol/fluticasone were 9.2 (personalized-dosing) vs 7.6 (fixed-dosing) puffs (P < 0.001). The relative deviation of R_aw from the personal target was expressed as (measured R_aw - target R_aw)/target R_aw. The experimental group showed a smaller relative R_aw deviation than the control group (0.09 ± 0.10 vs 0.44 ± 0.11, P = 0.02). There were no differences between the two groups in terms of ventilator-free days from day 1 to day 28, number of episodes of nosocomial pneumonia, total number of puffs of rescue bronchodilator, number of drug-related adverse effects or mortality rate at day 180.

CONCLUSION

Personalized dosing of inhaled bronchodilator administered to invasively ventilated COPD patients can produce a better reduction in R_aw. Further studies with larger sample size are required to verify the conclusion of this pilot study.

Does educating nurses with ventilator-associated pneumonia prevention guidelines improve their compliance?

BACKGROUND

This study aimed to compare the compliance with ventilator-associated pneumonia (VAP)-prevention guidelines between nurses who underwent an intensive educational program and those who did not, and to investigate other factors that influence nurses' compliance.

METHOD

A 2-group posttest design was used to examine the effect of the VAP-prevention guidelines education on nurses' compliance. Participants were randomly assigned to experimental and control groups.

RESULTS

The overall nurses' compliance scores were moderate. There was no statistically significant difference in compliance between the nurses who received VAP education and those who did not (t[100] = -1.43; P = .15). The number of beds in the unit and the nurse-patient ratio were found to influence nurses' compliance.

CONCLUSION

Education in VAP-prevention guidelines will not improve nurses' compliance unless other confounding factors, such as their workload, are controlled. It is imperative to reduce nurses' workload to improve their compliance and enhance the effectiveness of education.

Impact of oral hygiene involving toothbrushing versus chlorhexidine in the prevention of ventilator-associated pneumonia: a randomized study

BACKGROUND

Nosocomial pneumonia has correlated to dental plaque and to oropharynx colonization in patients receiving mechanical ventilation. The interruption of this process, by preventing colonization of pathogenic bacteria, represents a potential procedure for the prevention of ventilator-associated pneumonia (VAP).

METHODS

The study design was a prospective, randomized trial to verify if oral hygiene through toothbrushing plus chlorhexidine in gel at 0.12% reduces the incidence of ventilatior-associated pneumonia, the duration of mechanical ventilation, the length of hospital stay and the mortality rate in ICUs, when compared to oral hygiene only with chlorhexidine, solution of 0.12%, without toothbrushing, in adult individuals under mechanical ventilation, hospitalized in Clinical/Surgical and Cardiology Intensive Care Units (ICU). The study protocol was approved by the Ethical Committee of Research of the Health Sciences Center of the Federal University of Pernambuco - Certificate of Ethical Committee Approval (CAAE) 04300012500005208. Because it was a randomized trial, the research used CONSORT 2010 checklist criteria.

RESULTS

Seven hundred sixteen patients were admitted into the ICU; 219 fulfilled the criteria for inclusion and 213 patients were included; 108 were randomized to control group and 105 to intervention group. Toothbrushing plus 0.12% chlorhexidine gel demonstrated a lower incidence of VAP throughout the follow up period, although the difference was not statistically significant (p = 0.084). There was a significant reduction of the mean time of mechanical ventilation in the toothbrushing group (p = 0.018). Regarding the length of hospital stay in the ICU and mortality rates, the difference was not statistically significant (p = 0.064).

CONCLUSIONS

The results obtained showed that, among patients undergoing toothbrushing there was a significant reduction in duration of mechanical ventilation, and a tendency to reduce the incidence of VAP and length of ICU stay, although without statistical significance.

TRIAL REGISTRATION

Retrospectively registered in the Brazilian Clinical Trials Registry (Registro Brasileiro de Ensaios Clínicos) - RBR-4TWH4M (4 September 2016).

Design and Construction of a Microcontroller-Based Ventilator Synchronized with Pulse Oximeter

This study aims to introduce a novel device with which mechanical ventilator and pulse oximeter work in synchronization. Serial communication technique was used to enable communication between the pulse oximeter and the ventilator. The SpO2 value and the pulse rate read on the pulse oximeter were transmitted to the mechanical ventilator through transmitter (Tx) and receiver (Rx) lines. The fuzzy-logic-based software developed for the mechanical ventilator interprets these values and calculates the percentage of oxygen (FiO2) and Positive End-Expiratory Pressure (PEEP) to be delivered to the patient. The fuzzy-logic-based software was developed to check the changing medical states of patients and to produce new results (FiO2 ve PEEP) according to each new state. FiO2 and PEEP values delivered from the ventilator to the patient can be calculated in this way without requiring any arterial blood gas analysis. Our experiments and the feedbacks from physicians show that this device makes it possible to obtain more successful results when compared to the current practices.

Staffing patterns of respiratory therapists in critical care units of Canadian teaching hospitals

BACKGROUND

The optimal level of respiratory therapy staffing in Canadian intensive care units (ICUs) has not been described in the literature. An examination of practice patterns is an essential first step in developing an understanding of the contribution of respiratory therapists (RTs) to both short- and long-term patient outcomes in this context.

OBJECTIVE

To identify the ratio of mechanically ventilated patients to respiratory therapist (Vent:RT ratio) in the ICUs of Canadian teaching hospitals and the factors that influence this ratio.

METHODS

The present observational study investigated all adult ICUs (n=38) of the primary teaching hospital associated with each Canadian medical school. An electronic survey was administered at three intervals over a period of three months to control for seasonal variation. Data collected included the hours worked by all RTs, the number of mechanically ventilated patients receiving care, ICU characteristics and the practice patterns of the RTs. Data were used to calculate the Vent:RT ratio, and repeated measures ANOVA examined for variation between findings of each of the data collection points. Correlation analyses between key variables were performed and identified associations were further explored using the t test. Approval for the study was granted by the University of Manitoba Research Ethics Board (Winnipeg, Manitoba).

RESULTS

A mean (± SD) Vent:RT ratio of 5.1:1±2.818 was determined. Repeated measures ANOVA demonstrated no significant differences between findings of the three data collection points (F [1.7,30.5]=0.695; P=0.492). Several variables were associated with a significant difference in the Vent:RT ratio including ICUs where RTs insert arterial monitoring lines (4.05±2.89 versus 6.97±2.85; t[17.6]=-2.64; P=0.02), neurological ICUs (4.04±2.76 versus 6.40±3.35; t[30]=-2.092; P=0.04) and coronary care units (5.72±2.80 versus 3.10±1.88; t[35]=2.72; P=0.01). Significant differences were also identified in the mean number of RT hours worked in ICUs where RTs intubated (31.40±9.71 versus 60.54±47.20; t(13)=-2.17; P=0.049) and procured arterial blood gases (41.68±30.85 versus 77.33±46.22; t[35]=-2.79; P=0.01).

CONCLUSIONS

The present study is the first to report the Vent:RT ratio and RT practice patterns in Canadian adult ICUs. The results serve as a baseline for comparison of staffing norms and will enlighten future research on the impact of RT staffing and practice patterns on patient outcomes.

The influence of music during mechanical ventilation and weaning from mechanical ventilation: A review

Mechanical ventilation (MV) causes many distressing symptoms. Weaning, the gradual decrease in ventilator assistance leading to termination of MV, increases respiratory effort, which may exacerbate symptoms and prolong MV. Music, a non-pharmacological intervention without side effects may benefit patients during weaning from mechanical ventilatory support. A narrative review of OVID Medline, PsychINFO, and CINAHL databases was conducted to examine the evidence for the use of music intervention in MV and MV weaning. Music intervention had a positive impact on ventilated patients; 16 quantitative and 2 qualitative studies were identified. Quantitative studies included randomized clinical trials (10), case controls (3), pilot studies (2) and a feasibility study. Evidence supports music as an effective intervention that can lesson symptoms related to MV and promote effective weaning. It has potential to reduce costs and increase patient satisfaction. However, more studies are needed to establish its use during MV weaning.

Healthcare Technology Management (HTM) of mechanical ventilators by clinical engineers

Mechanical ventilator failures expose patients to unacceptable risks, and maintaining mechanical ventilator safety is an important issue. We examined the usefulness of maintaining mechanical ventilators by clinical engineers (CEs) using a specialized calibrator. These evaluations and the ability to make in-house repairs proved useful for obviating the need to rent ventilators which, in turn, might prove faulty themselves. The CEs' involvement in maintaining mechanical ventilators is desirable, ensures prompt service, and, most importantly, enhances safe management of mechanical ventilators.