To ventilate, oscillate, or cannulate?

Venovenous extracorporeal membrane oxygenation for respiratory failure refractory to high frequency percussive ventilation

BACKGROUND

High frequency percussive ventilation (HFPV) has demonstrated improvements in gas exchange, but not in clinical outcomes.

OBJECTIVES

We utilize HFPV in patients failing conventional ventilation (CV), with rescue venovenous extracorporeal membrane oxygenation (VV ECMO) reserved for failure of HFPV, and we describe our experience with such a strategy.

METHODS

All adult patients (age >18 years) placed on HFPV for failure of CV at a single institution over a 10-year period were included. Those maintained on HFPV were compared to those that failed HFPV and required VV ECMO. Survival was compared to expected survival after upfront VV ECMO as estimated by VV ECMO risk prediction models.

RESULTS

Sixty-four patients were placed on HFPV for failure of CV over a 10-year period. After HFPV initiation, the P/F ratio rose from 76mmHg to 153.3mmHg in the 69 % of patients successfully maintained on HFPV. The P/F ratio only rose from 60.3mmHg to 67mmHg in the other 31 % of patients, and they underwent rescue ECMO with the P/F ratio rising to 261.6mmHg. The P/F ratio continued to improve in HFPV patients, while it declined in ECMO patients, such that at 24 h, the P/F ratio was greater in HFPV patients. The strongest independent predictor of failure of HFPV requiring rescue VV ECMO was a lower pO2 (p = .055). Overall in-hospital survival (59.4 %) was similar to that expected with upfront ECMO (RESP score: 57 %).

CONCLUSIONS

HFPV demonstrated significant and sustained improvements in gas exchange and may obviate the need for ECMO and its associated complications.

Deep Learning Chest CT for Clinically Precise Prediction of Sepsis-Induced Acute Respiratory Distress Syndrome: A Protocol for an Observational Ambispective Cohort Study

Background: Sepsis commonly causes acute respiratory distress syndrome (ARDS), and ARDS contributes to poor prognosis in sepsis patients. Early prediction of ARDS for sepsis patients remains a clinical challenge. This study aims to develop and validate chest computed tomography (CT) radiomic-based signatures for early prediction of ARDS and assessment of individual severity in sepsis patients. Methods: In this ambispective observational cohort study, a deep learning model, a sepsis-induced acute respiratory distress syndrome (SI-ARDS) prediction neural network, will be developed to extract radiomics features of chest CT from sepsis patients. The datasets will be collected from these retrospective and prospective cohorts, including 400 patients diagnosed with sepsis-3 definition during a period from 1 May 2015 to 30 May 2022. 160 patients of the retrospective cohort will be selected as a discovering group to reconstruct the model and 40 patients of the retrospective cohort will be selected as a testing group for internal validation. Additionally, 200 patients of the prospective cohort from two hospitals will be selected as a validating group for external validation. Data pertaining to chest CT, clinical information, immune-associated inflammatory indicators and follow-up will be collected. The primary outcome is to develop and validate the model, predicting in-hospital incidence of SI-ARDS. Finally, model performance will be evaluated using the area under the curve (AUC) of receiver operating characteristic (ROC), sensitivity and specificity, using internal and external validations. Discussion: Present studies reveal that early identification and classification of the SI-ARDS is essential to improve prognosis and disease management. Chest CT has been sought as a useful diagnostic tool to identify ARDS. However, when characteristic imaging findings were clearly presented, delays in diagnosis and treatment were impossible to avoid. In this ambispective cohort study, we hope to develop a novel model incorporating radiomic signatures and clinical signatures to provide an easy-to-use and individualized prediction of SI-ARDS occurrence and severe degree in patients at early stage.

Prone positioning during venovenous extracorporeal membrane oxygenation for acute respiratory distress syndrome: a systematic review and meta-analysis

BACKGROUND

Prone positioning (PP) improves oxygenation and respiratory mechanics and is associated with lower mortality in patients with moderate to severe acute respiratory distress syndrome (ARDS). Despite this, some patients develop refractory hypoxemia and hypercapnia requiring venovenous extracorporeal membrane oxygenation (VV ECMO) support and are usually cared for in supine position. The physiologic and outcome benefits of routine PP of patients during VV ECMO remains unclear. Hence, we conducted the systematic review and meta-analysis to evaluate the outcome benefits of PP for patients with ARDS being treated with VV ECMO.

METHODS

After registration with PROSPERO (CRD42020199723), MEDLINE, EMBASE, Scopus and Cochrane databases were searched for relevant studies that reported PP in more than 10 adult patients supported with VV ECMO from origin to 1 March 2021. Studies were reviewed for quality using appropriate Joanna Briggs Institute (JBI) checklists, and certainty of evidence was assessed using the GRADE approach. The random-effects model (DerSimonian and Laird) was used. The primary outcome of interest was cumulative survival. Secondary outcomes were intensive care unit length of stay (ICU LOS) and ECMO duration. Changes in arterial blood gas (ABG) values, ventilator mechanics and complication rates were also studied.

RESULTS

Of 812 potentially relevant publications, 12 studies (640 patients) met our inclusion criteria. Due to overlapping study populations, 11 studies were included in the final meta-analysis. Cumulative survival in patients that underwent PP was 57% (95% CI 41.9-71.4, high certainty). Patients that underwent PP had longer ICU LOS (+ 14.5 days, 95% CI 3.4-25.7, p = 0.01) and ECMO duration (+ 9.6 days, 95% CI 5.5-13.7, p < 0.0001). After PP, patients had significantly higher PaO2/FiO2 ratio, lower PaCO2 and reduced ventilator driving pressure, and no major complications were reported.

CONCLUSIONS

PP during VV ECMO appears safe with a cumulative survival of 57% and may result in longer ECMO runs and ICU LOS. However, evidence from appropriately designed randomized trials is needed prior to widespread adoption of PP on VV ECMO.

Establishment of a novel miniature veno-venous extracorporeal membrane oxygenation model in the rat

Recently, veno-venous extracorporeal membrane oxygenation (V-V ECMO) has been commonly used in the world to support patients with severe respiratory failure. However, V-V ECMO is a new technology compared to veno-arterial extracorporeal membrane oxygenation and cardiopulmonary bypass, and there are few reports of basic research. Although continuing research is desired, clinical research that standardizes conditions such as patients' background characteristics is difficult. The purpose of this study was to establish a simple and stably maintainable miniature V-V ECMO model to study the mechanisms of the biological reactions in circulation during V-V ECMO. The V-V ECMO system consisted of an original miniature membrane oxygenator, polyvinyl chloride tubing line, and roller pump. The priming volume of this system was only 8 mL. Polyethylene tubing was used to cannulate the right femoral vein as the venous return cannula for the V-V ECMO system. A 16-G cannula was passed through the right internal jugular vein and advanced into the right atrium as the conduit for venous uptake. The animals were divided into 2 groups: SHAM group and V-V ECMO group. V-V ECMO was initiated and maintained at 50-60 mL/kg/min, and oxygen was added into the oxygenator during V-V ECMO at a concentration of 100% (pump flow:oxygen = 1:10). Blood pressure was measured continuously, and blood cells were measured by blood collection. During V-V ECMO, the blood pressure and hemodilution rate were maintained around 80 mm Hg and 20%, respectively. Hb was kept at >10 g/dL, and V-V ECMO could be maintained without blood transfusion. It was possible to confirm oxygenation of and carbon dioxide removal from the blood. Likewise, the pH was adequately maintained. There were no problems with this miniature V-V ECMO system, and extracorporeal circulation progressed safely. In this study, a novel miniature V-V ECMO model was established in the rat. A miniature V-V ECMO model appears to be very useful for studying the mechanisms of the biological reactions during V-V ECMO and to perform basic studies of circulation assist devices.

Does Earlier Cannulation With Veno-Venous Extracorporeal Membrane Oxygenation in Adult Patients With Acute Respiratory Distress Syndrome Decrease Duration of Artificial Mechanical Ventilation?

BACKGROUND

Acute respiratory distress syndrome (ARDS) is characterized by an acute, diffuse, inflammatory lung injury, leading to increased alveolar capillary permeability, increased lung weight, and loss of aerated lung tissue (Fan, Brodie, & Slutsky, 2018). Primary treatment for ARDS is artificial mechanical ventilation (AMV) (Wu, Huang, Wu, Wang, & Lin, 2016). Given recent advances in technology, the use of veno-venous extracorporeal membrane oxygenation (VV-ECMO) to treat severe ARDS is growing rapidly (Combes et al., 2014).

OBJECTIVE

This 49-month quantitative, retrospective inpatient EMR chart review compared if cannulation with VV-ECMO up to and including 48 hours of admission and diagnosis in adult patients 30 to 65 years of age diagnosed with ARDS, decreased duration on AMV, as compared to participants who were cannulated after 48 hours of admission and diagnosis with ARDS.

METHODS

A total of 110 participants were identified as receiving VV-ECMO during the study timeframe. Of the 58 participants who met all inclusion criteria, 39 participants were cannulated for VV-ECMO within 48 hours of admission and diagnosis with ARDS, and 19 participants were cannulated with VV-ECMO after 48 hours of admission and diagnosis with ARDS.

RESULTS

Data collected identified no statistically significant (p < 0.579) difference in length of days on AMV between participant groups.

CONCLUSIONS

Further studies are needed to determine if earlier initiation of VV-ECMO in adult patients with ARDS decrease time on AMV.

IMPLICATIONS FOR NURSING

Although the results related to length of time on AMV did not produce statistical significance, the decreased duration of AMV in the participants who were cannulated within 48 hours (21 days vs. 27 days) may support several benefits associated with this participant population including increased knowledge of healthcare providers, decreased lung injury, earlier discharge which decreases hospital and patient cost, ability for patients to communicate sooner, decreased risk of pulmonary infection, decreased length of stay, decreased cost, and improved patient and family satisfaction.

The evolution of Australian intensive care and its related costs: A narrative review

OBJECTIVE

To conduct a narrative review on the evolution of intensive care and the cost of intensive care services in Australia.

REVIEW METHOD

A narrative review using a search of online medical databases and grey literature with keyword verification via Delphi-technique.

DATA SOURCES

Using Medical Subject Headings and keywords (intensive care, critical care, mechanical ventilation, renal replacement therapy, extracorporeal membrane oxygenation, monitoring, staffing, cost, cost analysis) we searched MEDLINE, PubMed, CINAHL, Embase, Google and Google Scholar.

RESULTS

The search yielded 30 articles from which we provide a narrative synthesis on the evolving intensive care practice in relation to key service elements and therapies. For the review of costs, we found five relevant publications and noted significant variation in methods used to cost ICU. Notwithstanding the limitations of the methods used to cost all publications reported staffing as the primary cost driver, representing up to 71% of costs.

CONCLUSION

Intensive care is a highly specialised medical field, which has developed rapidly and plays an increasingly important role in the provision of hospital care. Despite the increasing importance of the specialty and the known resource intensity there is a paucity of data on the cost of providing this service. In Australia, staffing costs consistently represent the majority of costs associated with operating an ICU. This finding should be interpreted cautiously given the variation of methods used to cost ICU services and the limited number of available studies. Developing standardised methods to consistently estimate ICU costs which can be incorporated in research into the cost-effectiveness of alternate practice is an important step to ensuring cost-effective care.

ECMO in major burn patients: feasibility and considerations when multiple modes of mechanical ventilation fail

BACKGROUND

We report two cases of acute respiratory distress syndrome in burn patients who were successfully managed with good outcomes with extra corporeal membrane oxygenation (ECMO) after failing multiple conventional modes of ventilation, and review the relevant literature.

CASE PRESENTATION

The two patients were a 39-year-old male and 53-year-old male with modified Baux Scores of 79 and 78, respectively, with no known inhalation injury. After the initial modified Parkland-based fluid resuscitation and partial escharotomy, both patients developed worsening hypoxemia and acute respiratory distress syndrome. The hypoxemia continued to worsen on multiple modes of ventilation including volume control, pressure regulated volume control, pressure control, airway pressure release ventilation and volumetric diffusive ventilation. In both cases, the PaO₂ ≤ 50 mm Hg on a FiO₂ 100% during the trial of mechanical ventilation. The deterioration was rapid (<12 h since onset of worsening oxygenation) in both cases. A decision was made to trial the patients on ECMO. Veno-Venous ECMO (V-V ECMO) was successfully initiated following cannulation-under transesophgeal echo guidance-with the dual lumen Avalon® (Maquet, NJ, USA) cannula. ECMO support was maintained for 4 and 24 days, respectively. Both patients were successfully weaned off ECMO and were discharged to rehabilitation following their complex hospital course.

CONCLUSION

Early ECMO for isolated respiratory failure in the setting on maintained hemodynamics resulted in a positive outcome in our two burn patients suffered from acute respiratory distress syndrome.

Extracorporeal lung support in patients with spinal cord injury: Single center experience

OBJECTIVE

Trauma-related spinal cord injury (SCI) leads to a loss of motor, sensory and vegetative functions and is disproportionately associated with respiratory complications. SCI has a significant impact on respiratory muscle function and can lead to respiratory dysfunction or severe lung failure.

PARTICIPANTS

Between 2008 and 2014, 7 patients with severe lung failure following SCI received veno-venous extracorporeal membrane oxygenation (ECMO) n = 5 and interventional lung assist (iLA) n = 2.

RESULTS

The median duration of extracorporeal lung support was 8 (5.7-17.6) days. All 5 of the ECMO-supported patients were successfully weaned, and one of the two patients treated with iLA was weaned from the device. The median intensive care unit (ICU) stay was 35 (8.5-44.5) days. The mean hospital stay was 81 (8.5-120.7) days, and the average ventilation time was 817 (206-1,225) hours. Five (71.4%) of the 7 patients were discharged from the ICU and hospital.

CONCLUSIONS

In patients with SCI, serious complications include microatelectasis, infection, ventilation-perfusion mismatching and aspiration (special case: salt-water aspiration after jumping into shallow water). In patients with SCI with post-traumatic lung failure, ECMO is a feasible and life-saving procedure. After surviving spinal shock, a long rehabilitation period with intensive follow-up in specialized centers is required.

Extracorporeal life support devices and strategies for management of acute cardiorespiratory failure in adult patients: a comprehensive review

Evolution of extracorporeal life support (ECLS) technology has added a new dimension to the intensive care management of acute cardiac and/or respiratory failure in adult patients who fail conventional treatment. ECLS also complements cardiac surgical and cardiology procedures, implantation of long-term mechanical cardiac assist devices, heart and lung transplantation and cardiopulmonary resuscitation. Available ECLS therapies provide a range of options to the multidisciplinary teams who are involved in the time-critical care of these complex patients. While venovenous extracorporeal membrane oxygenation (ECMO) can provide complete respiratory support, extracorporeal carbon dioxide removal facilitates protective lung ventilation and provides only partial respiratory support. Mechanical circulatory support with venoarterial (VA) ECMO employed in a traditional central/peripheral fashion or in a temporary ventricular assist device configuration may stabilise patients with decompensated cardiac failure who have evidence of end-organ dysfunction, allowing time for recovery, decision-making, and bridging to implantation of a long-term mechanical circulatory support device and occasionally heart transplantation. In highly selected patients with combined severe cardiac and respiratory failure, advanced ECLS can be provided with central VA ECMO, peripheral VA ECMO with timely transition to venovenous ECMO or VA-venous ECMO upon myocardial recovery to avoid upper body hypoxia or by addition of an oxygenator to the temporary ventricular assist device circuit. This article summarises the available ECLS options and provides insights into the principles and practice of these techniques. One should emphasise that, as is common with many emerging therapies, their optimal use is currently not backed by quality evidence. This deficiency needs to be addressed to ensure that the full potential of ECLS can be achieved.

Towards a proactive therapy utilizing the modern spectrum of extracorporeal life support: a single-centre experience

BACKGROUND

We describe a single-centre experience of extracorporeal life support (ELS) for patients with severe and refractory cardiogenic shock, refractory cardiac arrest and severe respiratory failure.

METHODS

Between September 2007 and September 2012, 56 intra-hospital and 10 inter-hospital adult patients were supported.

RESULTS

The median ELS duration was 3 (0.9 - 6) days in venoarterial and 9.2 (7.4 - 24.4) days in venovenous supported patients. At hospital discharge and follow-up (12 and 40 months), survival among the respiratory (venovenous) patients and cardiac (venoarterial) patients was 84% and 38%, respectively. Survival in severe refractory cardiogenic shock patients was related to early initiation of ELS (<8 hours of onset of failure). A delay in initiating venoarterial ELS (>8 hours) and increased pre-ELS pH and lactate levels were associated with death in all cardiomyopathy patients, independent of infarct size.

CONCLUSIONS

Our results exemplify the benefits of ELS as a bridge to initial stabilization of critically ill patients. Potentially, the early application of ELS technology can lower mortality and morbidity in patients with a regressive pathology.