Use Of Lung-protective Strategies Research Articles

Factors Associated With Prolonged Ventilation in Patients Receiving Prone Positioning Protocol With Muscle Relaxants for Severe COVID-19 Pneumonia.

Prone positioning and neuromuscular blocking agents (NMBAs) are frequently used to treat severe respiratory failure from COVID-19 pneumonia. Prone positioning has shown to improve mortality, whereas NMBAs are used to prevent ventilator asynchrony and reduce patient self-inflicted lung injury. However, despite the use of lung-protective strategies, high death rates in this patient population have been reported. We retrospectively examined the factors affecting prolonged mechanical ventilation in subjects receiving prone positioning plus muscle relaxants. The medical records of 170 patients were reviewed. Subjects were divided into 2 groups according to ventilator-free days (VFDs) at day 28. Whereas subjects with VFDs < 18 d were defined as prolonged mechanical ventilation, subjects with VFDs ≥18 d were defined as short-term mechanical ventilation. Subjects' baseline status, status at ICU admission, therapy before ICU admission, and treatment in the ICU were studied. Under the proning protocol for COVID-19, the mortality rate in our facility was 11.2%. The prognosis may be improved by avoiding lung injury in the early stages of mechanical ventilation. According to multifactorial logistic regression analysis, persistent SARS-CoV-2 viral shedding in blood (P = .03), higher daily corticosteroid use before ICU admission (P = .007), delayed recovery of lymphocyte count (P < .001), and higher maximal fibrinogen degradation products (P = .039) were associated with prolonged mechanical ventilation. A significant relationship was found between daily corticosteroid use before admission and VFDs by squared regression analysis (y = -0.00008522x2 + 0.01338x + 12.8; x: daily corticosteroids dosage before admission [prednisolone mg/d]; y: VFDs/28 d, R2 = 0.047, P = .02). The peak point of the regression curve was 13.4 d at 78.5 mg/d of the equivalent prednisolone dose, which corresponded to the longest VFDs. Persistent SARS-CoV-2 viral shedding in blood, high corticosteroid dose from the onset of symptoms to ICU admission, slow recovery of lymphocyte counts, and high levels of fibrinogen degradation products after admission were associated with prolonged mechanical ventilation in subjects with severe COVID-19 pneumonia.

Lung Isolation

Lung isolation is being used more frequently in adult patients due to increasing incidence of thoracoscopy and video-assisted thoracoscopic surgery. There are several indications for lung isolation and one-lung ventilation (OLV) during surgery. Isolation is usually achieved by double-lumen endotracheal tubes or use of some type of bronchial blocker system. The initiation of OLV frequently leads to hypoxemia, the management of which should be stepwise. Additionally, clinical outcomes are significantly improved with the use of lung protective strategies during OLV. This review covers the use of few of the most common lung isolation devices, management of OLV using lung protective ventilation strategies, and management of oxygenation and hypoxemia during OLV. This review contains 12 figures, 6 tables, and 36 references. Key Words: bronchial blockers, double-lumen tube, uninvent, hypoxemia, hypoxic pulmonary vasoconstriction, one lung ventilation, positive end expiratory pressure, tracheal anatomy, lung isolation

DIFFERENCES IN LUNG PROTECTIVE VENTILATION USE IN FEMALE VS MALE ORGAN DONORS

SESSION TITLE: Transplantation SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/10/2018 01:00 PM - 02:00 PM PURPOSE: Given that 15% of patients on the lung transplant list die waiting for a transplant, it is imperative that potential donors be managed optimally to preserve suitable organs. At present, the proportion of potential lungs judged suitable for transplant is only 15-25%. Lung protective ventilation strategies, largely focused on the use of lower tidal volumes (TVs), have been shown to improve outcomes in both ARDS and non-ARDS ICU patients, leading to the recommendation for TVs <=8ml/kg PBW for patients without lung injury, and <=6ml/kg PBW in ARDS. However, adherence to lung protective ventilation remains poor, with women and shorter patients receiving excessive TVs more frequently. With increasing evidence supporting the use of lung protective strategies in potential organ donors, we examined our institutions adherence to lung protective ventilation and whether similar sex disparities exist in this population. METHODS: We analyzed every patient accepted for organ donation at our institution from 2009-2016 (n=112) and a 2:1 randomly matched group of patients referred for donation but who were medically ruled out. We extracted ventilator data, demographic information and arterial blood gas data in 4-hour intervals for the 48 hours preceding the time of death. Data were analyzed to determine patient factors associated with receiving excessive TVs (>8cc/kg PBW). RESULTS: 65% of all subjects received excessive TVs during the 48 hours prior to death, and subjects received excessive TVs during 40% of all measured time points. Frequency of receiving excessive TVs did not differ between donors and rule-outs. 76% of women received excessive TVs at some point, compared to 57% of men (p<0.001). Women were also 50% more likely to receive excessive TVs of greater than 10ml/kg (12% vs 8%, p<0.001). Women received excessive TVs 46% of the time vs. 32% for men (p<0.001). Women also spent more time receiving excessive TVs (11h vs 7h, p<.001) than men. The association between female sex and excessive TVs remained significant after multiple regression analysis adjusting for height, BMI, trauma death and donation outcome (p=0.01). Other independent predictors of excessive TVs were morbid obesity, shorter height, and trauma as a cause of death (all p<0.001). CONCLUSIONS: We show that potential organ donors frequently did not receive appropriate low TV ventilation in the transplant evaluation period. Furthermore, women were less likely to receive lung protective tidal volumes. This association remains even after adjusting for other factors associated with receiving large TVs, including obesity and shorter height. CLINICAL IMPLICATIONS: While this is a single-center retrospective review, it suggests the possibility of an important disparity. Our findings suggest the need for larger, multi-center studies to determine the impact of excessive tidal volumes on organ suitability and outcomes. DISCLOSURES: No relevant relationships by Joaquin Chapa, source=Web Response No relevant relationships by Stephanie Nonas, source=Web Response

Use of lung-protective strategies during one-lung ventilation surgery: a multi-institutional survey.

Limited evidence suggests that intraoperative lung-protective ventilation (LPV) during one-lung ventilation (OLV) may reduce respiratory complications after thoracic surgery. Little is known about LPV practices during OLV. Our purpose was to assess the state of practice/perspectives of anesthesiologists regarding LPV during elective OLV. We conducted a multi-institutional cross-sectional survey of anesthesiologists performing OLV at high-volume Canadian tertiary/university centers. The survey was designed, refined and distributed by a multi-disciplinary team using the Dillman method. Univariable and multivariable analyses were used. Seventy-five (63%) of 120 eligible respondents completed the survey. Although the critical care literature focuses on minimizing tidal volume (TV) as the central strategy of LPV, most respondents (89%, n=50/56) focused on minimizing peak airway pressure (PAP) as their primary strategy of intraoperative LPV. Only 64% (n=37/58) reported actively trying to minimize TV. While 32% (n=17/54) were unsure about the current evidence regarding LPV, 67% (n=36/54) believed that the evidence favoured their use during OLV. Perceived clinical and institutional barriers were the only predictors of reduced attempts to minimize TV on univariate analyses. In multivariable/adjusted analyses, perceived institutional barriers were the only predictors of reduced attempts to minimize TV with adjusted odds ratio of 0.1 (95% CI: 0.03-0.6). Most anesthesiologists defined low PAP as the primary strategy of LPV during OLV and attempted to minimize it. This study is the first to assess the practice/perspectives of anesthesiologists regarding LPV during OLV and also the first to explore predictors of LPV use. Randomized trials are currently ongoing. However, this study suggests that institutional barriers may subvert future knowledge translation and need to be addressed.

Community-acquired Pneumonia and Acute Respiratory Distress Syndrome: Prevalence, Risk, and Prognosis

Severe community-acquired pneumonia is the most common cause of acute respiratory distress syndrome (ARDS). Despite multiple improvements in the last 10 years, this syndrome remains highly prevalent worldwide and is associated with high mortality and long-term morbidity rates. Several factors are related to the increasing risk of ARDS. Clinicians should be familiar with the use of lung-protective strategies and the mechanism of ventilator-induced lung injury, as ventilator management of ARDS is complex. Clinical trials are now needed, to investigate adjunctive therapies in patients with severe pneumonia and ARDS, such as systemic corticosteroids.

What's new in mechanical ventilation in patients without ARDS: lessons from the ARDS literature.

Introduction The incidence of acute respiratory distress syndrome (ARDS) varies greatly across the world [1], and its impact on the outcome of critically ill patients remains significant [1]. The publication of the ARMA trial [2] demonstrated that a lung protective strategy of ventilation, using a tidal volume (VT) of 6 ml/kg predicted body weight (PBW), decreased mortality in patients with ARDS, and led to the widespread, albeit not universal, use of lung protective strategies in this group of patients. Recent studies suggest that the incidence of ARDS is decreasing [3, 4] and that this reduction is believed to be a result of advances in hospital practice and numerous quality improvement initiatives [4]. These advances included general quality improvement initiatives (i.e. infection control, timely antibiotics and resuscitation) and also specific critical care protocols such as the use of protective ventilation in critically ill patients without ARDS [5, 6]. Since the majority of the patients undergoing mechanical ventilation do not have ARDS, the number of studies focusing on strategies of ventilation in this group of patients has been increasing in recent years, both in surgical and non-surgical areas. The purpose of this paper is to review the recent evidence in mechanical ventilation in patients without ARDS.

Mechanical ventilation in acute hypoxemic respiratory failure: a review of new strategies for the practicing hospitalist.

The goal of mechanical ventilation in acute hypoxemic respiratory failure is to support adequate gas exchange without harming the lungs. How patients are mechanically ventilated can significantly impact their ultimate outcomes. This review focuses on emerging evidence regarding strategies for mechanical ventilation in patients with acute hypoxemic respiratory failure including: low tidal volume ventilation in the acute respiratory distress syndrome (ARDS), novel ventilator modes as alternatives to low tidal volume ventilation, adjunctive strategies that may enhance recovery in ARDS, the use of lung-protective strategies in patients without ARDS, rescue therapies in refractory hypoxemia, and an evidence-based approach to weaning from mechanical ventilation. Once a patient is intubated and mechanically ventilated, low tidal volume ventilation remains the best strategy in ARDS. Adjunctive therapies in ARDS include a conservative fluid management strategy, as well as neuromuscular blockade and prone positioning in moderate-to-severe disease. There is also emerging evidence that a lung-protective strategy may benefit non-ARDS patients. For patients with refractory hypoxemia, extracorporeal membrane oxygenation should be considered. Once the patient demonstrates signs of recovery, the best approach to liberation from mechanical ventilation involves daily spontaneous breathing trials and protocolized assessment of readiness for extubation. Prompt recognition of ARDS and use of lung-protective ventilation, as well as evidence-based adjunctive therapies, remain the cornerstones of caring for patients with acute hypoxemic respiratory failure. In the absence of contraindications, it is reasonable to consider lung-protective ventilation in non-ARDS patients as well, though the evidence supporting this practice is less conclusive.

Respiratory dialysis: Reduction in dependence on mechanical ventilation by venovenous extracorporeal CO2 removal*

Mechanical ventilation is injurious to the lung. Use of lung-protective strategies may complicate patient management, motivating a search for better lung-replacement approaches. We investigated the ability of a novel extracorporeal venovenous CO2 removal device to reduce minute ventilation while maintaining normocarbia. Prospective animal study. Government laboratory animal intensive care unit. Seven sedated swine. Tracheostomy, volume-controlled mechanical ventilation, and 72 hrs of round-the-clock intensive care unit care. A 15-F dual-lumen catheter was inserted in the external jugular vein and connected to the Hemolung, an extracorporeal pump-driven venovenous CO2 removal device. Minute ventilation was reduced, and normocarbia (Paco2 35-45 mm Hg) maintained. Heparinization was maintained at an activated clotting time of 150-180 secs. Minute ventilation (L/min), CO2 removal by Hemolung (mL/min), Hemolung blood flow, O2 consumption (mL/min), CO2 production by the lung (mL/min), Paco2, and plasma-free hemoglobin (g/dL) were measured at baseline (where applicable), 2 hrs after device insertion, and every 6 hrs thereafter. Minute ventilation was reduced from 5.6 L/min at baseline to 2.6 L/min 2 hrs after device insertion and was maintained at 3 L/min until the end of the study. CO2 removal by Hemolung remained steady over 72 hrs, averaging 72 ± 1.2 mL/min at blood flows of 447 ± 5 mL/min. After insertion, O2 consumption did not change; CO2 production by the lung decreased by 50% and stayed at that level (p < .001). As the arterial PCO2 rose or fell, so did CO2 removal by Hemolung. Plasma-free hemoglobin did not change. Venovenous CO2 removal enabled a 50% reduction in minute ventilation while maintaining normocarbia and may be an effective lung-protective adjunct to mechanical ventilation.

Anesthesia Literature Review

Anesthesia Literature Review

Acute Lung Injury Is an Independent Risk Factor for Brain Hypoxia After Severe Traumatic Brain Injury

Pulmonary complications are frequently observed after severe traumatic brain injury (TBI), but little is known about the consequences of lung injury on brain tissue oxygenation and metabolism. We examined the association between lung function and brain tissue oxygen tension (PbtO2) in patients with severe TBI. We analyzed data from 78 patients with severe, nonpenetrating TBI who underwent continuous PbtO2 and intracranial pressure monitoring. Acute lung injury was defined by the presence of pulmonary infiltrates with a PaO2/FiO2 (PF) ratio less than 300 and the absence of left ventricular failure. A total of 587 simultaneous measurements of PbtO2 and PF ratio were examined using longitudinal data analysis. PbtO2 correlated strongly with PaO2 and PF ratio (P < .05) independent of PaCO2, brain temperature, cerebral perfusion pressure, and hemoglobin. Acute lung injury was associated with lower PbtO2 (34.6 +/- 13.8 mm Hg at PF ratio >300 vs 30.2 +/- 10.8 mm Hg [PF ratio 200-300], 28.9 +/- 9.8 mm Hg [PF ratio 100-199], and 21.1 +/- 7.4 mm Hg [PF ratio <100], all P values <.01). After adjusting for intracranial pressure, Marshall computed tomography score, and APACHE II (Acute Physiology and Chronic Health Evaluation) score, acute lung injury was an independent risk factor for compromised PbtO2 (PbtO2 <20 mm Hg; adjusted odds ratio: 2.13, 95% confidence interval: 1.21-3.77; P < .01). After severe TBI, PbtO2 correlates with PF ratio. Acute lung injury is associated with an increased risk of compromised PbtO2, independent from intracerebral and systemic injuries. Our findings support the use of lung-protective strategies to prevent brain hypoxia in TBI patients.

Ventilação mecânica na lesão pulmonar aguda / síndrome do desconforto respiratório agudo

The II Brazilian Consensus Conference on Mechanical Ventilation was published in 2000. Knowledge on the field of mechanical ventilation evolved rapidly since then, with the publication of numerous clinical studies with potential impact on the ventilatory management of critically ill patients. Moreover, the evolving concept of evidence - based medicine determined the grading of clinical recommendations according to the methodological value of the studies on which they are based. This explicit approach has broadened the understanding and adoption of clinical recommendations. For these reasons, AMIB - Associação de Medicina Intensiva Brasileira and SBPT - Sociedade Brasileira de Pneumologia e Tisiologia - decided to update the recommendations of the II Brazilian Consensus. Acute Respiratory Distress Syndrome (ARDS) has been one of the updated topics. This objective was described the most important topics related to mechanical ventilation in patients with acute respiratory distress syndrome. Systematic review of the published literature and gradation of the studies in levels of evidence, using the key words mechanical ventilation and acute respiratory distress syndrome. Recommendations on the use of lung protective strategies during mechanical ventilation based on reduced tidal volumes and limitation of plateau pressure. The state of the art of recruitment maneuvers and PEEP titration is also discussed. The mechanical ventilation of patients with ADRS changed in the last few years. We presented the role of lung protective strategies that could be applied to these patients.

Management of blast injuries and shock lung

Blast injuries have always occurred both in civilian life and as acts of war or terrorism. Nowadays, the risk of being involved in an explosion has increased even for those living in countries with no previous experience of such events. It is our intention that this review is of assistance to those providing emergency/critical care to patients who have sustained blast injuries. Exposure to blast may indirectly produce physiological insults such as bradycardia, hypotension, tissue hypoxia and oxidative stress. The use of early goal-directed therapy might be important in minimizing such insults. Explosions in an enclosed environment are associated with increased risk of pulmonary blast injury and also air and fat embolism. Mechanical ventilation after pulmonary blast injury is associated with barotrauma and the use of lung protective strategies previously recommended in acute lung injury may be beneficial. The potential for blast to cause injury depends on the nature of the explosive and environment in which the blast occurs. Soft tissue injury with environmental contamination is frequent. Optimal antimicrobial cover and strategies such as selective digestive decontamination may be advantageous. Early surgery should follow the principles of 'damage control'. Blast injury often leads to severe sepsis/systemic inflammatory response, multiple organ dysfunction and prolonged critical illness. In this clinical scenario, recent studies have shown improved outcome with the use of activated protein C, steroid replacement and aggressive control of blood glucose but have been less convincing regarding the use of immuno-nutrition.