Inhalation Injury, Respiratory Failure, and Ventilator Support in Acute Burn Care

Sustaining an inhalation injury increases the risk of severe complications and mortality. Current evidential support to guide treatment of the injury or subsequent complications is lacking, as studies either exclude inhalation injury or design limit inferences that can be made. Conventional ventilator modes are most commonly used, but there is no consensus on optimal strategies. Settings should be customized to patient tolerance and response. Data for pharmacotherapy adjunctive treatments are limited.

Parasternal Intercostal Muscle Thickness Fraction (PICTF%): Ultrasound a New Tool for Weaning Prediction?

How to cite this article: Bhattacharya D, Esquinas AM, Mandal M. Parasternal Intercostal Muscle Thickness Fraction (PICTF%): Ultrasound a New Tool for Weaning Prediction? Indian J Crit Care Med 2024;28(4):404.

The end-tidal alveolar dead space fraction for risk stratification during the first week of invasive mechanical ventilation: an observational cohort study

BACKGROUND

The end-tidal alveolar dead space fraction (AVDSf = [PaCO₂-P_ETCO₂]/PaCO₂) is a metric used to estimate alveolar dead space. Higher AVDSf on the first day of mechanical ventilation is associated with mortality and fewer ventilator-free days. It is not clear if AVDSf is associated with length of ventilation in survivors, how AVDSf performs for risk stratification beyond the first day of ventilation, or whether AVDSf adds predictive value to oxygenation (oxygenation index [OI]) or severity of illness (Pediatric Risk of Mortality [PRISM III]) markers.

METHODS

Retrospective single-center observational cohort study of children and young adults receiving invasive mechanical ventilation. In those with arterial or capillary blood gases, AVDSf was calculated at the time of every blood gas for the first week of mechanical ventilation.

RESULTS

There were 2335 children and young adults (median age 5.8 years [IQR 1.2, 13.2]) enrolled with 8004 analyzed AVDSf values. Higher AVDSf was associated with mortality and longer length of ventilation in survivors throughout the first week of ventilation after controlling for OI and PRISM III. Higher OI was not associated with increased mortality until ≥ 48 h of ventilation after controlling for AVDSf and PRISM III. When using standardized variables, AVDSf effect estimates were generally higher than OI for mortality, whereas OI effect estimates were generally higher than AVDSf for the length of ventilation in survivors. An AVDSf > 0.3 was associated with a higher mortality than an AVDSf < 0.2 within each pediatric acute respiratory distress syndrome severity category. The maximum AVDSf within 12 h of intensive care unit admission demonstrated good risk stratification for mortality (AUC 0.768 [95% CI 0.732, 0.803]). AVDSf did not improve mortality risk stratification when added to PRISM III but did improve mortality risk stratification when added to the gas exchange components of PRISM III (minimum 12-h PaO₂ and maximum 12-h PCO₂) (p < 0.00001).

CONCLUSIONS

AVDSf is associated with mortality and length of ventilation in survivors throughout the first week of invasive mechanical ventilation. Some analyses suggest AVDSf may better stratify mortality risk than OI, whereas OI may better stratify risk for prolonged ventilation in survivors than AVDSf.

How businesses are working together to deliver NASA/JPL-designed ventilators to the world in the fight against COVID-19

In response to the COVID-19 pandemic, NASA Jet Propulsion Laboratory (JPL) engineers had embarked on an ambitious project to design a reliable, easy-to-use, and low-cost ventilator that was made of readily available parts to address the unexpected global shortage of these lifesaving devices. After successfully designing and building the VITAL (Ventilator Intervention Technology Accessible Locally) ventilator in record time, FDA Emergency Use Authorization (EUA) was obtained and then the license to manufacture and sell these ventilators was made available to select companies through a competitive process. STARK Industries, LLC (STARK), located in Columbus, OH, USA, was one of only eight U.S. companies to be selected to receive this worldwide license. Motivated by its mission to improve human health and well-being through innovated medical technologies, STARK accepted the challenge of further developing the VITAL technology and manufacturing the ventilators in large quantities and making them available to those in need around the world. To this end, Spiritus Medical, Inc (Spiritus) was spun off from STARK to focus on the ventilator business. Through collaborative efforts with various corporate, academic, governmental, and non-profit partners, Spiritus was able to successfully begin manufacturing and selling its ventilators. Due to its low-cost nature and its straightforward design, this ventilator is ideal for use in developing countries where ventilators are in short supply and affordability is a major consideration. This is a story of how NASA's ingenuity, based on space-based know-how and experience, was used to rapidly design this innovative ventilator. And by forging partnerships with highly qualified and motivated partners such as STARK and Spiritus, NASA has succeeded in translating this work into technology that could potentially save thousands of lives in the fight against the COVID-19 pandemic.

Assessment of hemodynamics, blood gases, and lung histopathology of healthy Pig model on two different mechanical ventilators

In response to COVID-19 global crisis and arising from social responsibility, efforts have been exerted to promptly research, develop and manufacture ICU ventilators locally to meet the spike in demand. This study aimed at: Evaluating the safety and performance of a newly developed mechanical ventilator; EZVent compared to a commercial ventilator regarding hemodynamics, arterial blood gases (ABG), lung inflammatory markers, and histopathology in a healthy pig model using three different ventilation modes. Methods: Eight adult male pigs were anesthetized and randomly assigned into two equal groups: Commercial vent and EZVent group, the animals of which were ventilated using a standard commercial ventilator and EZVent, respectively. On every animal, three ventilation modes were tested, each mode for 30 min: CMV-VC, CMV-PC, and CPAP-PS modes. Vital signs, ECG, Lung Mechanics (LM), and ABG were measured before ventilation and after 30 min of ventilation of each mode. After animals’ euthanasia, histological examinations of lung samples including morphometric assessment of alveolar edema, alveolar wall thickening, and the mean number of inflammatory cellular infiltrate/cm² of lung tissue were analyzed. TNF-α and Il-6 expression and localization in lung tissue were assessed by western blot and immunohistochemistry. Results: The vital signs, LM, ABG, morphometric analysis, and histopathological score during the different ventilation modes showed non-significant differences between the study groups. TNF-α and IL-6 were minimally expressed in the bronchiolar epithelium and the alveolar septa. Their increased expression level was insignificant. Conclusion: EZVent is equivalent to the commercial ventilator regarding its safety and efficacy.

Lessons from the frontline: Documenting the pandemic emergency care experience from the Pacific region - Infrastructure and equipment

Background

The COVID-19 pandemic highlighted challenges for all health systems worldwide. This research aimed to explore the impact of COVID-19 across the Pacific especially with regards to emergency care (EC) and clinicians' preparations and responses.

Methods

A collaboration of Australia and Pacific researchers conducted prospective qualitative research over 18 months of the pandemic. In this three phase study data were gathered from Emergency Clinicians and stakeholders through online support forums, in-depth interviews and focus groups. A phenomenological methodological approach was employed to explore the lived experience of participants. This paper discusses the findings of the study regarding the EC building block of 'Infrastructure and Equipment.'

Findings

Pre-existing infrastructure and equipment were not sufficient to help control the pandemic. Adequate space and correct equipment were essential needs for Pacific Island emergency clinicians, with donations, procurement and local ingenuity required for suitable, sustainable supplies and facilities. Adequate personal protective equipment (PPE) conferred a sense of security and increased Health Care Workers willingness to attend to patients.

Interpretation

Investing in adequate infrastructure and appropriate equipment is crucial for an effective response to the COVID-19 pandemic. The sustainability of such investments in the Pacific context is paramount for ongoing EC and preparation for future surge responses and disasters.

Funding

Phases 1 and 2A of this study were part of an Epidemic Ethics/World Health Organization (WHO) initiative, supported by Foreign, Commonwealth and Development Office/Wellcome Grant 214711/Z/18/Z. Co-funding for this research was received from the Australasian College for Emergency Medicine Foundation via an International Development Fund Grant.

A Rationale for Safe Ventilation with Inhalation Injury: An Editorial Review

Lung injury from smoke inhalation manifests as airway and parenchymal damage, at times leading to the acute respiratory distress syndrome. From the beginning of this millennium, the approach to mechanical ventilation in the patient with ARDS was based on reduction of tidal volume to 6 milliliters/kilogram of ideal body weight, maintaining a ceiling of plateau pressure, and titration of driving pressure (plateau pressure minus PEEP). Beyond these broad constraints, there is little specification for the mechanics of ventilator settings, consideration of the metabolic impact of the disease process on the patient, or interaction of patient disease and ventilator settings. Various studies suggest that inhomogeneity of lung injury, which increases the risk of regional lung trauma from mechanical ventilation, may be found in the patient with smoke inhalation. We now appreciate that energy transfer principles may affect optimal ventilator management and come into play in damaged heterogenous lungs. Mechanical ventilation in the patient with inhalation injury should consider various factors. Self-injurious respiratory demand by the patient can be reduced using analgesia and sedation. Dynamic factors beginning with rate management can reduce the incidence of potentially damaging ventilation. Moreover, preclinical study is underway to examine the flow of gas based on the ventilator mode selected, which may also be a factor triggering regional lung injury.

Accelerated innovation in crises: The role of collaboration in the development of alternative ventilators during the COVID-19 pandemic

This article discusses the need for accelerated innovation in crisis situations and argues that collaboration plays an important role in enabling such acceleration. The central research question is: How can innovation efforts during crises be accelerated, and what role does collaboration play? We draw on a phenomenon-driven, in-depth qualitative case study of seven initiatives that have developed alternative ventilators in the Netherlands during the COVID-19 crisis. Our results highlight how the COVID-19 pandemic has created a relatively short crisis window of opportunity for accelerated innovation processes that is driven by the urgency to develop solutions to the challenge at hand. Importantly, we show that when collaborative initiatives join other collaborative initiatives- what we define as nested collaboration-a forum for coordinated knowledge and resource exchange between the initiatives is created, increasing the potential for learning and accelerating the innovation process. Finally, we find that purpose is an important intermediating mechanism to accelerate innovation as it enables non-competitive collaboration between the initiatives in favor of the public good. Our results have important implications for accelerated innovation processes to achieve societal missions, goals, or challenges.

Mechanical power in pediatric acute respiratory distress syndrome: a PARDIE study

BACKGROUND

Mechanical power is a composite variable for energy transmitted to the respiratory system over time that may better capture risk for ventilator-induced lung injury than individual ventilator management components. We sought to evaluate if mechanical ventilation management with a high mechanical power is associated with fewer ventilator-free days (VFD) in children with pediatric acute respiratory distress syndrome (PARDS).

METHODS

Retrospective analysis of a prospective observational international cohort study.

RESULTS

There were 306 children from 55 pediatric intensive care units included. High mechanical power was associated with younger age, higher oxygenation index, a comorbid condition of bronchopulmonary dysplasia, higher tidal volume, higher delta pressure (peak inspiratory pressure-positive end-expiratory pressure), and higher respiratory rate. Higher mechanical power was associated with fewer 28-day VFD after controlling for confounding variables (per 0.1 J·min-1·Kg-1 Subdistribution Hazard Ratio (SHR) 0.93 (0.87, 0.98), p = 0.013). Higher mechanical power was not associated with higher intensive care unit mortality in multivariable analysis in the entire cohort (per 0.1 J·min-1·Kg-1 OR 1.12 [0.94, 1.32], p = 0.20). But was associated with higher mortality when excluding children who died due to neurologic reasons (per 0.1 J·min-1·Kg-1 OR 1.22 [1.01, 1.46], p = 0.036). In subgroup analyses by age, the association between higher mechanical power and fewer 28-day VFD remained only in children < 2-years-old (per 0.1 J·min-1·Kg-1 SHR 0.89 (0.82, 0.96), p = 0.005). Younger children were managed with lower tidal volume, higher delta pressure, higher respiratory rate, lower positive end-expiratory pressure, and higher PCO2 than older children. No individual ventilator management component mediated the effect of mechanical power on 28-day VFD.

CONCLUSIONS

Higher mechanical power is associated with fewer 28-day VFDs in children with PARDS. This association is strongest in children < 2-years-old in whom there are notable differences in mechanical ventilation management. While further validation is needed, these data highlight that ventilator management is associated with outcome in children with PARDS, and there may be subgroups of children with higher potential benefit from strategies to improve lung-protective ventilation.

TAKE HOME MESSAGE

Higher mechanical power is associated with fewer 28-day ventilator-free days in children with pediatric acute respiratory distress syndrome. This association is strongest in children <2-years-old in whom there are notable differences in mechanical ventilation management.

Prolonged mechanical ventilation after cardiac surgery: substudy of the Transfusion Requirements in Cardiac Surgery III trial

PURPOSE

Prolonged mechanical ventilation (MV) is a major complication following cardiac surgery. We conducted a secondary analysis of the Transfusion Requirements in Cardiac Surgery (TRICTS) III trial to describe MV duration, identify factors associated with prolonged MV, and examine associations of prolonged MV with mortality and complications.

METHODS

Four thousand, eight hundred and nine participants undergoing cardiac surgery at 71 hospitals worldwide were included. Prolonged MV was defined based on the Society of Thoracic Surgeons definition as MV lasting 24 hr or longer. Adjusted associations of patient and surgical factors with prolonged MV were examined using multivariable logistic regression. Associations of prolonged MV with complications were assessed using odds ratios, and adjusted associations between prolonged MV and mortality were evaluated using multinomial regression. Associations of shorter durations of MV with survival and complications were explored.

RESULTS

Prolonged MV occurred in 15% (725/4,809) of participants. Prolonged MV was associated with surgical factors indicative of complexity, such as previous cardiac surgery, cardiopulmonary bypass duration, and separation attempts; and patient factors such as critical preoperative state, left ventricular impairment, renal failure, and pulmonary hypertension. Prolonged MV was associated with perioperative but not long-term complications. After risk adjustment, prolonged MV was associated with perioperative mortality; its association with long-term mortality among survivors was weaker. Shorter durations of MV were not associated with increased risk of mortality or complications.

CONCLUSION

In this substudy of the TRICS III trial, prolonged MV was common after cardiac surgery and was associated with patient and surgical risk factors. Although prolonged MV showed strong associations with perioperative complications and mortality, it was not associated with long-term complications and had weaker association with long-term mortality among survivors.

STUDY REGISTRATION

www.

CLINICALTRIALS

gov (NCT02042898); registered 23 January 2014. This is a substudy of the Transfusion Requirements in Cardiac Surgery (TRICS) III trial.

The Effect of Sedation Protocol on Sedation Level and Pharmacological and Non-Pharmacological Interventions on Mechanically Ventilated Patients

Background:

The use of analgesics and sedatives to provide sedation for Patients in Intensive Care Unit (ICU) is inevitable. The present study aimed to determine the effect of sedation protocol using the Richmond Agitation- Sedation Scale on sedation level and amount of pharmacological and non-pharmacological interventions on patients under mechanical ventilation.

Materials and Methods:

This randomized clinical trial was conducted on 79 patients under mechanical ventilation in Zanjan. The patients were recruited using the blocking randomized sampling method. In the experiment group, the sedation was provided hourly, using the Richmond sedation Protocol, during the mechanical ventilation period. The level of sedation and pharmacological and nonpharmacological interventions were compared in the two groups using Fisher exact test.

Results:

Totally, 40 patients in the experiment and 39 patients in the control groups were evaluated. No significant difference was found between the two groups in terms of confounding variables (age, sex, level of consciousness, Acute Physiologic and Chronic Health Evaluation (APACHE) II criterion, underlying disease, and cause of hospitalization). The level of sedation in the experiment group was significantly closer to the ideal score of the Richmond Scale compared to the control group (p < 0.001). The experimental group received significantly more non-pharmacological interventions and fewer pharmacological interventions compared to the control group (P < 0.001).

Conclusions:

Using a sedation protocol could provide better sedation levels in patients under mechanical ventilation, and reduce the use of sedative medications, and consequently, the cost of hospitalization. Further research is suggested.

Snakebite incidents, prevention and care during COVID-19: Global key-informant experiences

Snakebite envenoming is a long-neglected disease causing significant morbidity and mortality in snakebite endemic low- and middle-income countries (LMICs). Global awareness on snakebite was increasing steadily up to 2020, and an increasing number of countries began to acknowledge the issue, when coronavirus disease 2019 (COVID-19) started to have an unprecedented impact on societies and health systems. To better understand how snakebite incidents, prevention and care are being affected during this global emergency, we collected perspectives of snakebite community- and health system stakeholders in a qualitative key-informant study. An open-ended survey and semi-structured interviews were conducted to gather information on changes in snakebite occurrence and circumstances, community responses, access to care and health outcomes in LMICs since the COVID-19 pandemic. Forty-three informants from 21 countries participated in the study. Based on informants' experiences, in spite of COVID-19 lockdowns, exposure to snakes did not change in many rural agrarian communities, where incidences are usually highest. However, we did find several access to care issues relating to avoidance of formal care, transport barriers, overburdened healthcare systems and -providers, and antivenom manufacturing and supply disruptions, which were unique per context. On a brighter note, ventilator availability had increased in several countries, although not automatically benefitting snakebite patients directly. In conclusion, we found apparent effects of the COVID-19 pandemic on snakebite prevention and care, although its severity was highly context- and time-dependent. Interactions between the pandemic effects and snakebite incidents most severely impact remote rural communities, showing the need to invest in community-based prevention and care.

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The COVID-19 pandemic has impacted snakebite prevention and care in LMICs.

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Healthcare avoidance and transport barriers have resulted in additional morbidity and mortality.

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Increased ventilator availability could have a positive effect on snakebite care in specific settings.

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Treatment of snakebites at primary level health facilities can significantly reduce snakebite morbidity and mortality.

The incidence and characteristics of ventilator-associated pneumonia in a regional nontertiary Australian intensive care unit: A retrospective clinical audit study

BACKGROUND

Ventilator-associated pneumonia (VAP) is a common complication of mechanical ventilation in the intensive care unit. The incidence, patient characteristics, and outcomes have not been described in a regional Australian setting.

OBJECTIVES

Τhe primary objective was to establish the incidence of VAP in a regional intensive care unit using predetermined diagnostic criteria. The secondary objective was to compare the agreement between criteria-based and physician-based diagnostic processes. The tertiary objectives were to compare patient characteristics and clinical outcomes of cases with and without VAP.

METHODS

A retrospective clinical audit was performed of adult patients admitted to Rockhampton Intensive Care Unit, Australia, between 2013 and 2016. We included all patients ventilated for ≥72 h and not diagnosed with a pneumonia before or during the first 72 h of ventilation.

RESULTS

A total of 170 cases met the inclusion criteria. The incidence of VAP as per the criteria-based diagnosis was 27.3 cases per 1000 ventilator days (95% confidence interval [CI]: 18.4-36.2) and as per the physician-based diagnosis was 25.8 cases per 1000 ventilator days (95% CI: 17.1-34.4). There was a moderate chance-corrected agreement between the criteria- and physician-based diagnosis. Very obese cases (body mass index [BMI] ≥40) were nearly four times more likely to develop VAP than cases with normal BMI (BMI <30) (odds ratio: 3.664; 95% CI: 1.394-9.634; p = 0.008). After controlling for sex, BMI category, comorbidities, and Acute Physiology and Chronic Health Evaluation II scores, there was a trend (p = 0.283) for higher adjusted mortality rate for cases with VAP (10.1%, 95% CI: 4.8-21.5) than for those without VAP (6.1%, 95% CI: 3.0-12.4). Cases with VAP had a higher total hospital cost ($123,223 AUD vs $66,425 AUD, p < 0.001), than cases without VAP.

CONCLUSIONS

This is the first study reporting incidence of VAP in an Australian regional intensive care unit setting. An increased length of stay and significantly higher hospital costs warrant research investigating reliable and valid clinical prediction rules to forecast those at risk of VAP.

COVID-19, triage decisions, and indirect ethics: A model for the re-evaluation of triage guidelines

The COVID-19 pandemic has overwhelmed healthcare systems in several countries and has led to situations in which the number of critically ill patients has exceeded the number of ICU beds and ventilators. In anticipation of a potential shortage of ventilators, many countries developed triage guidelines to handle such situations. However, at the current stage in the pandemic there have been a few initial indications that these guidelines may suffer from problems of feasibility. If these suspicions are confirmed in the time to come when systematic studies are conducted, this will provide a strong reason for re-evaluating the guidelines. This article provides a model for the re-evaluation of the existing triage guidelines that draws on insight into indirect ethics and which is designed to ensure that we can learn from the costly experiences during the course of the COVID-19 pandemic.

Noninvasive Home Mechanical Ventilation in Adult Myotonic Dystrophy Type 1: A Systematic Review

INTRODUCTION

Chronic hypercapnic respiratory failure induces considerable morbidity and mortality in patients with myotonic dystrophy type 1 (DM1). This study systematically reviews the effects of noninvasive home mechanical ventilation (HMV) on gas exchange, quality of life, survival, and compliance in DM1 patients.

METHODS

A systematic Medline and Embase search was performed (January 1995 to January 2020). Records were screened for eligibility criteria, data were extracted from included studies, and risk of bias was assessed. We present findings mainly using a narrative synthesis.

RESULTS

Twenty-eight relevant full-text articles were screened for eligibility criteria. Nine studies were included. Randomized controlled trials were not found. Studies had either an observational (n = 8) or interventional (n = 1) design. In the pooled data analysis, HMV showed to improve mean oxygen saturation with 4.8% and decreased mean carbon dioxide values with 3 mm Hg. Compliance varied widely between studies, from no use to more than 12 h per day. Quality of life was not studied extensively, but some studies reported positive effects of HMV on symptoms of chronic respiratory failure. HMV may improve survival in DM1 patients with chronic hypercapnic respiratory failure.

CONCLUSION

This review shows that HMV can improve gas exchange and relieve symptoms with a possible survival benefit in DM1 patients with chronic hypercapnic respiratory failure. Future studies should focus on developing strategies to optimize the timing of HMV initiation and to promote compliance.

Systematic review of cognitive impairment and brain insult after mechanical ventilation

We conducted a systematic review following the PRISMA protocol primarily to identify publications that assessed any links between mechanical ventilation (MV) and either cognitive impairment or brain insult, independent of underlying medical conditions. Secondary objectives were to identify possible gaps in the literature that can be used to inform future studies and move toward a better understanding of this complex problem. The preclinical literature suggests that MV is associated with neuroinflammation, cognitive impairment, and brain insult, reporting higher neuroinflammatory markers, greater evidence of brain injury markers, and lower cognitive scores in subjects that were ventilated longer, compared to those ventilated less, and to never-ventilated subjects. The clinical literature suggests an association between MV and delirium, and that delirium in mechanically ventilated patients may be associated with greater likelihood of long-term cognitive impairment; our systematic review found no clinical study that demonstrated a causal link between MV, cognitive dysfunction, and brain insult. More studies should be designed to investigate ventilation-induced brain injury pathways as well as any causative linkage between MV, cognitive impairment, and brain insult.

Geographic access to COVID-19 healthcare in Brazil using a balanced float catchment area approach

The rapid spread of COVID-19 across the world has raised concerns about the responsiveness of cities and healthcare systems during pandemics. Recent studies try to model how the number of COVID-19 infections will likely grow and impact the demand for hospitalization services at national and regional levels. However, less attention has been paid to the geographic access to COVID-19 healthcare services and to hospitals' response capacity at the local level, particularly in urban areas in the Global South. This paper shows how transport accessibility analysis can provide actionable information to help improve healthcare coverage and responsiveness. It analyzes accessibility to COVID-19 healthcare at high spatial resolution in the 20 largest cities of Brazil. Using network-distance metrics, we estimate the vulnerable population living in areas with poor access to healthcare facilities that could either screen or hospitalize COVID-19 patients. We then use a new balanced floating catchment area (BFCA) indicator to estimate spatial, income, and racial inequalities in access to hospitals with intensive care unit (ICU) beds and mechanical ventilators while taking into account congestion effects. Based on this analysis, we identify substantial social and spatial inequalities in access to health services during the pandemic. The availability of ICU equipment varies considerably between cities, and it is substantially lower among black and poor communities. The study maps territorial inequalities in healthcare access and reflects on different policy lessons that can be learned for other countries based on the Brazilian case.

Beyond Individual Triage: Regional Allocation of Life-Saving Resources such as Ventilators in Public Health Emergencies

In the first wave of the COVID-19 pandemic, healthcare workers in some countries were forced to make distressing triaging decisions about which individual patients should receive potentially life-saving treatment. Much of the ethical discussion prompted by the pandemic has concerned which moral principles should ground our response to these individual triage questions. In this paper we aim to broaden the scope of this discussion by considering the ethics of broader structural allocation decisions raised by the COVID-19 pandemic. More specifically, we consider how nations ought to distribute a scarce life-saving resource across healthcare regions in a public health emergency, particularly in view of regional differences in projected need and existing capacity. We call this the regional triage question. Using the case study of ventilators in the COVID-19 pandemic, we show how the moral frameworks that we might adopt in response to individual triage decisions do not translate straightforwardly to this regional-level triage question. Having outlined what we take to be a plausible egalitarian approach to the regional triage question, we go on to propose a novel way of operationalising the 'save the most lives' principle in this context. We claim that the latter principle ought to take some precedence in the regional triage question, but also note important limitations to the extent of the influence that it should have in regional allocation decisions.

Preventing infectious diseases in Intensive Care Unit by medical devices remote control: Lessons from COVID-19

The management of COVID-19 patients in the ICUs requires several and prolonged life-support systems (mechanical ventilation, continuous infusions of medications and nutrition, renal replacement therapy). Parameters have to be entered continuously into the device user interface by healthcare personnel according to the dynamic clinical condition. This leads to an increased risk of cross-contamination, use of personal protective equipment and the need for stringent and demanding protocols. Cables and tubing extensions have been utilized to make certain devices usable outside the patient's room but at the cost of introducing further hazards. Remote control of these devices decreases the frequency of unnecessary interventions and reduces the risk of exposure for both patients and healthcare personnel.

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healthcare-associated Infections (including respiratory viral and bacterial infections) are increasing especially in high-risk areas such as ICUs

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the management of critically ill patients requires several and prolonged life-support devices (ventilators, extracorporeal circuits, infusion pumps) increasing the risk of cross-contamination by aerosol, infected organic fluids or direct contact

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remote control of these devices, from a separated control-room, reduces unnecessary personnel biohazard exposure and contacts for both patients and healthcare workers

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bidirectional communication with medical equipment has potential to prevent contamination of patients and medical staff by limiting the spread of infections and allows for time and cost saving due to the reduced need of PPE

Maintaining Mobility in a Patient Who Is Pregnant and Has COVID-19 Requiring Extracorporeal Membrane Oxygenation: A Case Report

OBJECTIVE

Mobilization while receiving life support interventions, including mechanical ventilation and extracorporeal membrane oxygenation (ECMO), is a recommended intensive care unit (ICU) intervention to maintain physical function. The purpose of this case report is to describe a novel approach to implementing early mobility interventions for a patient who was pregnant and receiving ECMO while continuing necessary infectious disease precautions because of diagnosed coronavirus disease-19 (COVID-19).

METHODS

A 27-year-old woman who was pregnant was admitted to the ICU with COVID-19 and rapidly developed acute respiratory failure requiring 9 days of ECMO support. After a physical therapist consultation, the patient was standing at the bedside by hospital day 5 and ambulating by hospital day 9.

RESULTS

The patient safely participated in physical therapy during ICU admission and was discharged to home with outpatient physical therapy follow-up after 14 days of hospitalization.

CONCLUSION

Early mobility is feasible during ECMO with COVID-19, and active participation in physical therapy, including in-room ambulation, may facilitate discharge to home. Innovative strategies to facilitate routine activity in a patient who is critically ill with COVID-19 require an established and highly trained team with a focus on maintaining function.

IMPACT

Early mobility while intubated, on ECMO, and infected with COVID-19 is feasible while adhering to infectious disease precautions when it is performed by an experienced interdisciplinary team.

Evaluation of pressure in water-filled endotracheal tube cuffs in intubated patients undergoing hyperbaric oxygen treatment

INTRODUCTION

Inflating endotracheal tube cuffs using water instead of air before hyperbaric oxygen treatment (HBOT) is common. The objective of this study was to assess cuff pressure (P_cuff), when the cuff was inflated using water, in normobaric conditions and during HBOT.

METHODS

This was a prospective, observational study taking place in hyperbaric centre and intensive care unit of the University Hospital of Lille. Every patient who required tracheal intubation and HBOT at 253.3 kPa (2.5 atmospheres absolute [atm abs]) was included. P_cuff was measured using a pressure transductor connected to the cuff inflating port. Measurements were performed at 'normobaria' (1 atm abs) and during HBOT at 2.5 atm abs.

RESULTS

Thirty patients were included between February and April 2016. Recordings were analysable in 27 patients. Mean P_cuff at normobaria was 60.8 (SD 42) cmH₂O. Nineteen (70%) of patients had an excessive P_cuff (higher than 30 cmH₂O). Coefficient of variation was 69%. Mean P_cuff at 2.5 atm abs was 51.6 (40.7) cmH₂O, significantly lower than at normobaria (P < 0.0001). Coefficient of variation was 79%. In only five (18%) patients was P_cuff < 20 cmH₂O at 2.5 atm abs.

CONCLUSIONS

In normobaric conditions, when the cuff was inflated using water and not specifically controlled P_cuff was not predictable. The cuff was typically over-inflated exceeding safe pressure. During HBOT P_cuff decreased slightly.

Additive manufacturing in fighting against novel coronavirus COVID-19

Nowadays, COVID-19 also known as novel coronavirus has become a global pandemic by causing severe respiratory tract infections in humans without any definite treatment or vaccine. Therefore, disease control measures include slowing down or averting the transfer of this viral infection from person to person. Continuous efforts are carried out to avoid the transmission of this disease to frontline healthcare personnel using single-use personal protective equipment (PPE). However, a critical shortage in this equipment around the world is becoming an alarming concern. Therefore, it is vital to present a possible alternative to overcome the acute shortage of protective gear such as face masks against this infectious disease which can have universal accessibility and is easily available. Additive manufacturing (AM), also known as 3D printing, is a possible solution to overcome the shortage of protective gear and can play a vital role in supporting their conventional production supplies during this global pandemic situation. In this context, this paper provides a brief background study of COVID-19, its conventional preventive measure, and a detailed overview regarding the latest AM efforts including designers' providers and makers in the 3D printing community. Moreover, numerous inquiries and questions such as technical factors, testing recommendations and characterization methods and biological concerns such as biocompatibility and sterilization for the AM manufactured medical devices are addressed in this paper. In the end, two examples of AM medical devices, i.e., face mask and Ambu bag ventilator, are presented and studied through numerical simulations.

Increasing ventilator surge capacity in COVID 19 pandemic: design, manufacture and in vitro-in vivo testing in anaesthetized healthy pigs of a rapid prototyped mechanical ventilator

Objective

The advent of new technologies has made it possible to explore alternative ventilator manufacturing to meet the worldwide shortfall for mechanical ventilators especially in pandemics. We describe a method using rapid prototyping technologies to create an electro-mechanical ventilator in a cost effective, timely manner and provide results of testing using an in vitro–in vivo testing model.

Results

Rapid prototyping technologies (3D printing and 2D cutting) were used to create a modular ventilator. The artificial manual breathing unit (AMBU) bag connected to wall oxygen source using a flow meter was used as air reservoir. Controlled variables include respiratory rate, tidal volume and inspiratory: expiratory (I:E) ratio. In vitro testing and In vivo testing in the pig model demonstrated comparable mechanical efficiency of the test ventilator to that of standard ventilator but showed the material limits of 3D printed gears. Improved gear design resulted in better ventilator durability whilst reducing manufacturing time (< 2-h). The entire cost of manufacture of ventilator was estimated at 300 Australian dollars. A cost-effective novel rapid prototyped ventilator for use in patients with respiratory failure was developed in < 2-h and was effective in anesthetized, healthy pig model.

COVID-19 patients in a tertiary US hospital: Assessment of clinical course and predictors of the disease severity

INTRODUCTION

Patients with severe COVID-19 can develop ventilator-dependent acute hypoxic respiratory failure (VDAHRF), which is associated with a higher mortality rate. We evaluated the clinical course of hospitalized COVID-19 patients and compared them with the patients who received invasive mechanical ventilation. Characteristics of intubated patients who were successfully weaned from the ventilator were compared with the patients who failed to be extubated or died in the hospital.

OBJECTIVE

To investigate the clinical course of hospitalized COVID-19 patients, and assess the possible predictors of the disease severity leading to VDAHRF.

METHODS

This is a single-center, retrospective study. The first 129 patients (18 years or older) with COVID-19 admitted to Monmouth Medical Center from March 1st to April 25th, 2020 were included.

RESULTS

Out of 129 patients, 23.25% (n = 30) required invasive mechanical ventilation, and of those, six patients were successfully weaned from the ventilator. Multivariable logistic regression analysis showed increased odds of intubation associated with hypoxemia (odds ratio 17.23, 95% CI 5.206-57.088; p < 0.0001), elevated d-dimer by one unit mg/L of FEU (odds ratio 1.515, 95% CI 5.206-57.088; p = 0.0430) and elevated ferritin by one unit ng/ml (odds ratio 1.001, 95% CI 1.000-1.001, p = 0.0051) on admission, adjusted for other covariates.

CONCLUSIONS

Patients who required invasive mechanical ventilation were more likely to have older age, male gender, coronary artery disease, diabetes, and obesity. The patients who were successfully weaned from the ventilator were more likely to be younger in age, and none of them had heart failure or CAD.

Locally Informed Simulation to Predict Hospital Capacity Needs During the COVID-19 Pandemic

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic challenges hospital leaders to make time-sensitive, critical decisions about clinical operations and resource allocations.

OBJECTIVE

To estimate the timing of surges in clinical demand and the best- and worst-case scenarios of local COVID-19-induced strain on hospital capacity, and thus inform clinical operations and staffing demands and identify when hospital capacity would be saturated.

DESIGN

Monte Carlo simulation instantiation of a susceptible, infected, removed (SIR) model with a 1-day cycle.

SETTING

3 hospitals in an academic health system.

PATIENTS

All people living in the greater Philadelphia region.

MEASUREMENTS

The COVID-19 Hospital Impact Model (CHIME) (http://penn-chime.phl.io) SIR model was used to estimate the time from 23 March 2020 until hospital capacity would probably be exceeded, and the intensity of the surge, including for intensive care unit (ICU) beds and ventilators.

RESULTS

Using patients with COVID-19 alone, CHIME estimated that it would be 31 to 53 days before demand exceeds existing hospital capacity. In best- and worst-case scenarios of surges in the number of patients with COVID-19, the needed total capacity for hospital beds would reach 3131 to 12 650 across the 3 hospitals, including 338 to 1608 ICU beds and 118 to 599 ventilators.

LIMITATIONS

Model parameters were taken directly or derived from published data across heterogeneous populations and practice environments and from the health system's historical data. CHIME does not incorporate more transition states to model infection severity, social networks to model transmission dynamics, or geographic information to account for spatial patterns of human interaction.

CONCLUSION

Publicly available and designed for hospital operations leaders, this modeling tool can inform preparations for capacity strain during the early days of a pandemic.

PRIMARY FUNDING SOURCE

University of Pennsylvania Health System and the Palliative and Advanced Illness Research Center.

Challenges and solutions in meeting up the urgent requirement of ventilators for COVID-19 patients

BACKGROUND

Severely affected patients in the COVID-19 pandemic need Ventilators, we chart the challenges faced by the health care systems in procuring these machines and the role of 3-D printing technology in building ventilators.

AIMS

We tried to find the current role, availability and need of ventilators in the COVID-19 pandemic and the role of applied innovative technologies is assessed.

METHODS

We have done a comprehensive review of the literature using suitable keywords on the search engines of PubMed, SCOPUS, Google Scholar and Research Gate in the second week of April 2020.

RESULTS

We found in our review that there is an acute shortage of the ventilators and the manpower to operate these sophisticated machines. There is significant deficiency in the production and supply chain of the ventilators. Many of the seriously ill patients who require hospitalization may need ventilator support. Non-invasive ventilation is not recommended in these patients.

CONCLUSION

As the respiratory illness due to COVID-19 pandemic spreads worldwide, health care systems are facing the tough challenges of acquiring ventilators to support patients. All steps involved in the supply chain management of ventilators are being escalated to produce more ventilators for the coronavirus frontline. Innovative applications of Additive medicine like 3-D printer technology may play key role in delivering sufficient ventilators.

Usability Issues with Mechanical Ventilation Devices

The user interface of a mechanical ventilator is safety critical, as use errors can lead to patient harm. A systematic review was conducted to identify published usability issues and contributing factors that can lead to use errors. The findings were grouped in an Ishikawa diagram. Many of the problems mentioned based on inconsistent labeling and manufacturer-specific naming of ventilation modes. In the studies, usability was often measured quantitatively and did not allow any conclusions to be drawn about concrete problems.

Echocardiography in Pandemic: Front-Line Perspective, Expanding Role of Ultrasound, and Ethics of Resource Allocation

The grave clinical context of the coronavirus disease 2019 (COVID-19) pandemic must be understood. Italy is immersed in the COVID-19 pandemic. Most of the world will soon follow. The United States currently has the most documented cases of COVID-19 of any nation. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-associated acute cardiomyopathy is common in critical care patients and is associated with a high mortality rate. Patients with COVID-19 frequently require mechanical support for adequate oxygenation. A severe shortfall of ventilators is predicted. Of equal concern is the projected shortage of trained professionals required to care for patients on mechanical ventilation. Ultrasonography is proving to be a valuable tool for identifying the pulmonary manifestations and progression of COVID-19. Lung ultrasound also facilitates successful weaning from mechanical ventilation. Ultrasonography of the lung, pleura, and diaphragm are easily mastered by experienced echocardiographers. Echocardiography has an established role for optimal fluid management and recognition of cardiac disease, including SARS-CoV-2-associated acute cardiomyopathy. Cardiologists, anesthesiologists, sonographers, and all providers should be prepared to commit their full spectrum of skills to mitigate the consequences of the pandemic. We should also be prepared to collaborate and cross-train to expand professional services as necessary. During a declared health care crisis, providers must be familiar with the ethical principles, organizational structure, practical application, and gravity of limited resource allocation.

Thousands Of Lives Could Be Saved In The US During The COVID-19 Pandemic If States Exchanged Ventilators

It is thought that there are not enough mechanical ventilators in the United States for every patient who may need one during the novel coronavirus disease (COVID-19) pandemic. However, there has been no analysis that measures the potential magnitude of the problem or proposes a solution. In this article I combine the pandemic forecasting model used by the federal government with estimates of ventilator availability from the literature to assess the expected shortage under various scenarios. I then propose that the federal government organize a national effort for ventilators to be exchanged between states to take advantage of the intertemporal differences in demand peaks. I evaluate versions of this proposal, including use of the national stockpile, to estimate the potentially substantial number of lives that could be saved. In the absence of other viable solutions, the government should begin this effort in earnest, or else make preparations for such coordination should the country face another pandemic in the future.

Iatrogenic Opioid Withdrawal Syndrome in Critically Ill Patients: a Retrospective Cohort Study

BACKGROUND

Opioid withdrawal syndrome (OWS) may occur following the reduction or discontinuation of opioid analgesics. In critically ill pediatric patients, OWS is a common and clinically significant condition. However, OWS in adult patients has not been assessed in detail. Therefore, we aimed to investigate the incidence, risk factors, and clinical features of OWS in mechanically ventilated patients treated in an adult intensive care unit (ICU).

METHODS

This study was a retrospective evaluation of data from patients treated in the medical ICU for > 3 days and who received only one type of opioid analgesic. OWS was assessed over a 24 hours period from discontinuation or reduction (by > 50%) of continuous opioid infusion. OWS was defined as the presence of ≥ 3 central nervous system or autonomic nervous system symptoms.

RESULTS

In 126 patients treated with remifentanil (n = 58), fentanyl (n = 47), or morphine (n = 21), OWS was seen in 31.0%, 36.2%, and 9.5% of patients, respectively (P = 0.078). The most common symptom was a change in respiratory rate (remifentanil, 94.4%; fentanyl, 76.5%; morphine, 100%). Multivariate Cox-proportional hazards model showed that OWS was negatively associated with morphine treatment (hazard ratio [HR], 0.17; 95% confidence interval [CI], 0.037-0.743) and duration of opioid infusion (HR, 0.566; 95% CI, 0.451-0.712).

CONCLUSION

OWS is not uncommon in mechanically ventilated adult patients who received continuous infusion of opioids for > 3 days. The use of morphine may be associated with a decreased risk of OWS.

Admission to the surgical intensive care unit during intensivist coverage is associated with lower incidence of postoperative acute kidney injury and shorter ventilator time

PURPOSE

This study aimed to assess the impact of intensivist coverage on the incidence of acute kidney injury (AKI) and ventilator time among patients postoperatively admitted to the intensive care unit (ICU).

METHODS

Adult patients postoperatively admitted to the ICU between January 2012 and December 2017 were retrospectively enrolled. The incidence of AKI within 72 h of surgery and the postoperative ventilator time were compared between the groups covered by intensivists and non-intensivists.

RESULTS

After propensity score (PS) matching, 5650 patients were included in the final analysis (2825 patients in each group). The incidence rate of AKI was significantly higher in the non-intensivist coverage group than in the intensivist coverage group (22.7% vs. 20.2%; P = 0.023). Moreover, logistic regression analysis in the PS-matched cohort showed that the incidence of postoperative AKI in the non-intensivist coverage group increased by 16% compared to that in the intensivist coverage group (odds ratio 1.16, 95% confidence interval 1.02-1.32; P = 0.023). Additionally, the median time of ventilator use in the non-intensivist coverage group was significantly longer than that in the intensivist coverage group [7.8 (interquartile range, IQR 2.6-13.8) h vs. 5.3 (1.8-8.3) h; P < 0.001].

CONCLUSION

High-intensity intensivist coverage is associated with a lower risk of postoperative AKI and shorter postoperative ventilator times. These findings suggested that in addition to medical trainees, initial management of surgical ICU patients by intensivists may lower the risk of AKI and facilitate early weaning from mechanical ventilation.

Effect of inspiratory rise time on sputum movement during ventilator hyperinflation in a test lung model

OBJECTIVES

Physiotherapists may use ventilator hyperinflation to enhance secretion clearance for intubated patients. This study investigated the effects of altering percentage inspiratory rise time (IRT) on sputum movement, ratio of peak inspiratory to expiratory flow rate (PIF:PEF ratio) and net peak expiratory flow (PEF) during ventilator hyperinflation in a test lung model.

DESIGN

Laboratory-based bench study.

INTERVENTIONS

Simulated sputum (two viscosities) was inserted into clean, clear tubing and connected between a ventilator and a resuscitation bag. Thirty-six ventilator hyperinflation breaths were applied for each 5% incremental increase in IRT between 0% and 20%.

MAIN OUTCOME MEASURES

The primary outcome was sputum displacement (cm). Secondary outcomes included PIF:PEF ratio and net PEF.

RESULTS

Significant cephalad sputum movement of 2.42cm (1.59 to 3.94) occurred with IRT between 5% and 20%, compared with caudad movement of 0.53 cm (0.31 to 1.53) at 0% IRT (median sputum movement difference 3.7cm, 95% confidence interval 2.2 to 4.8, P<0.001). Incremental increases in IRT percentage produced linear enhancements in PIF:PEF ratio and net PEF for both sputum concentrations (P<0.001). However, once the critical threshold for PIF:PEF ratio of 0.9 was achieved, the distance of sputum movement remained consistent for all IRT values exceeding 5%.

CONCLUSIONS

Significant increases in sputum movement occurred when IRT percentage was lengthened to achieve the optimal PIF:PEF ratio, irrespective of sputum viscosity. This provides a theoretical rationale for therapists to consider this technique when treating mechanically ventilated patients. As no additional sputum movement was seen beyond the critical PIF:PEF ratio threshold, a low IRT percentage may potentially be used to achieve effective sputum movement.

Neuromuscular blockade is associated with the attenuation of biomarkers of epithelial and endothelial injury in patients with moderate-to-severe acute respiratory distress syndrome

Background

Neuromuscular blockade (NMB) is a therapy for acute respiratory distress syndrome (ARDS). However, the mechanism by which NMB may improve outcome for ARDS patients remains unclear. We sought to determine whether NMB attenuates biomarkers of epithelial and endothelial lung injury and systemic inflammation in ARDS patients, and whether the association is dependent on tidal volume size and the initial degree of hypoxemia.

Methods

We performed a secondary analysis of patients enrolled in the ARDS network low tidal volume ventilation (ARMA) study. Our primary predictor variable was the number of days receiving NMB between study enrollment and day 3. Our primary outcome variables were the change in concentration of biomarkers of epithelial injury (serum surfactant protein-D (SP-D)), endothelial injury (von Willebrand factor (VWF)), and systemic inflammation (interleukin (IL)-8). Multivariable regression analysis was used to compare the change in biomarker concentration controlling for multiple covariates. Patients were stratified by treatment arm (12 versus 6 cm³/kg) and by an initial arterial oxygen tension (PaO₂) to fractional inspired oxygen (FiO₂) (P/F) ratio of 120.

Results

A total of 446 (49%) patients had complete SP-D, VWF, and IL-8 measurements on study enrollment and day 3. After adjusting for baseline differences, each day of NMB was associated with a decrease in SP-D (−23.7 ng/ml/day, p = 0.029), VWF (−33.5% of control/day, p = 0.015), and IL-8 (−362.6 pg/ml/day, p = 0.030) in patients with an initial P/F less than or equal to 120 and receiving low tidal volume ventilation. However, patients with a P/F ratio of greater than 120 or receiving high tidal volume ventilation had either no change or an increase in SP-D, WVF, or IL-8 concentrations.

Conclusion

NBM is associated with decreased biomarkers of epithelial and endothelial lung injury and systemic inflammation in ARDS patients receiving low tidal volume ventilation and those with a P/F ratio less than or equal to 120.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-1974-4) contains supplementary material, which is available to authorized users.

Stockpiling Ventilators for Influenza Pandemics

In preparing for influenza pandemics, public health agencies stockpile critical medical resources. Determining appropriate quantities and locations for such resources can be challenging, given the considerable uncertainty in the timing and severity of future pandemics. We introduce a method for optimizing stockpiles of mechanical ventilators, which are critical for treating hospitalized influenza patients in respiratory failure. As a case study, we consider the US state of Texas during mild, moderate, and severe pandemics. Optimal allocations prioritize local over central storage, even though the latter can be deployed adaptively, on the basis of real-time needs. This prioritization stems from high geographic correlations and the slightly lower treatment success assumed for centrally stockpiled ventilators. We developed our model and analysis in collaboration with academic researchers and a state public health agency and incorporated it into a Web-based decision-support tool for pandemic preparedness and response.

Admission of tetanus patients to the ICU: a retrospective multicentre study

Background

An extended course of tetanus (up to 6 weeks) requiring ICU admission and protracted mechanical ventilation (MV) may have a significant impact on short- and long-term survival. The subject is noteworthy and deserves to be discussed.

Methods

Twenty-two ICUs in France performed tetanus screenings on patients admitted between January 2000 and December 2014. Retrospective data were collected from hospital databases and through the registers of the town hall of the patients.

Results

Seventy patients were included in 15 different ICUs. Sixty-three patients suffered from severe or very severe tetanus according to the Ablett classification. The median age was 80 years [interquartile range 73–84], and 86% of patients were women. Ninety per cent of patients (n = 63) required MV for a median of 36 days [26–46], and 66% required administration of a neuromuscular-blocking agent for 23 days [14–29]. A nosocomial infection occurred in 43 patients (61%). ICU and 1-year mortality rates were 14% (n = 10) and 16% (n = 11), respectively. Forty-five per cent of deaths occurred during the first week. Advanced age, a higher SAPS II, any infection, and the use of vasopressors were significantly associated with a lower number of days alive without ventilator support by day 90. Age was the only factor that significantly differed between deceased and survivors at 1 year (83 [81–85] vs. 79 [73–84] years, respectively; p = 0.03). Sixty-one per cent of survivors suffered no impairment to their functional status.

Conclusion

In a high-income country, tetanus mainly occurs in healthy elderly women. Despite prolonged MV and extended ICU length of stay, we observed a low 1-year mortality rate and good long-term functional status.

Evaluation of the Effect of Nebulized N-Acetylcysteine on Respiratory Secretions in Mechanically Ventilated Patients: Randomized Clinical Trial

BACKGROUND

The purpose of our study was to evaluate an inexpensive and available method to reduce mucous impactions in mechanically ventilated patients.

METHODS

This randomized clinical trial was conducted on 40 mechanically ventilated patients aged 15-90 years. The patients were randomly allocated into two arms; 20 cases and 20 controls. The cases received N-acetylcysteine via their nebulizers, and the control group received normal saline three times a day for one day. We measured the density of respiratory secretion, plateau and peak airway pressures, and O2 saturation at baseline, 12 and 24 hours later.

RESULTS

Although the mean secretion density was significantly lower in the NAC group (F (1, 38)=8.61, P=0.006), but a repeated measures ANOVA with a Greenhouse-Geisser correction determined that the effect of NAC on mean secretion density did not differ significantly between time points (F (1, 38)=3.08, P=0.087). NAC increased O2 saturation significantly between time points (F (1.92, 73.1)=4.6, P=0.014). The plateau airway pressures were relatively stable throughout the study in the normal saline and NAC groups (F (1.95, 37.1)=0.67, P=0.513). The peak airway pressure did not change significantly during the study in the normal saline and NAC groups (F (1.52, 56.4)=0.91, P=0.384).

CONCLUSION

Considering the limitations of the study, nebulized NAC in mechanically ventilated patients was not effective more than normal saline nebulization in reducing the density of mucous plugs. The peak and plateau airway pressures were relatively stable throughout the study in both groups.

TRIAL REGISTRATION NUMBER

IRCT201104276312N1.

What is the role of the physiotherapist in paediatric intensive care units? A systematic review of the evidence for respiratory and rehabilitation interventions for mechanically ventilated patients

BACKGROUND

Physiotherapy in intensive care units (ICU) has traditionally focussed on the respiratory management of mechanically ventilated patients. Gradually, focus has shifted to include rehabilitation in adult ICUs, though evidence of a similar shift in the paediatric ICU (PICU) is limited.

OBJECTIVES

Review the evidence to determine the role of physiotherapists in the management of mechanically ventilated patients in PICU.

DATA SOURCES

A search was conducted of: PEDro, CINAHL, Medline, PubMed and the Cochrane Library.

ELIGIBILITY CRITERIA

Studies involving PICU patients who received physiotherapy while invasively ventilated were included in this review. Those involving neonatal or adult ICU patients, or patients on non-invasive or long-term ventilation, were not included in the study.

STUDY APPRAISAL

All articles were critically appraised by two reviewers and results were analysed descriptively.

RESULTS

Six studies on chest physiotherapy (CPT) met the selection criteria. Results support the use of the expiratory flow increase technique and CPT, especially manual hyperinflation and vibrations, for secretion clearance. Evidence does not support the routine use of either CPT or suction alone. No studies investigating rehabilitation in PICU met selection criteria.

LIMITATIONS

A lack of high level evidence was available to inform this review.

CONCLUSION

Evidence indicates that CPT is still the focus of physiotherapy intervention in PICU for mechanically ventilated patients, and supports its use for secretion clearance in this setting. PROSPERO register for systematic reviews (registration no. CRD42014009582).

Patient ventilator asynchrony in critically ill adults: frequency and types

BACKGROUND

Patient ventilator asynchrony (PVA) occurs frequently, but little is known about the types and frequency of PVA. Asynchrony is associated with significant patient discomfort, distress and poor clinical outcomes (duration of mechanical ventilation, intensive care unit and hospital stay).

METHODS

Pressure-time and flow-time waveform data were collected on 27 ICU patients using the Noninvasive Cardiac Output monitor for up to 90 min per subject and blinded waveform analysis was performed.

RESULTS

PVA occurred during all phases of ventilated breaths and all modes of ventilation. The most common type of PVA was Ineffective Trigger. Ineffective trigger occurs when the patient's own breath effort will not trigger a ventilator breath. The overall frequency of asynchronous breaths in the sample was 23%, however 93% of the sample experienced at least one incident of PVA during their observation period. Seventy-seven percent of subjects experienced multiple types of PVA.

CONCLUSIONS

PVA occurs frequently in a variety of types although the majority of PVA is ineffective trigger. The study uncovered previously unidentified waveforms that may indicate that there is a greater range of PVAs than previously reported. Newly described PVA, in particular, PVA combined in one breath, may signify substantial patient distress or poor physiological circumstance that clinicians should investigate.