The relation of pneumothorax and other air leaks to mortality in the acute respiratory distress syndrome

Ventilator management and risk of air leak syndrome in patients with SARS-CoV-2 pneumonia: a single-center, retrospective, observational study

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia is reportedly associated with air leak syndrome (ALS), including mediastinal emphysema and pneumothorax, and has a high mortality rate. In this study, we compared values obtained every minute from ventilators to clarify the relationship between ventilator management and risk of developing ALS.

METHODS

This single-center, retrospective, observational study was conducted at a tertiary care hospital in Tokyo, Japan, over a 21-month period. Information on patient background, ventilator data, and outcomes was collected from adult patients with SARS-CoV-2 pneumonia on ventilator management. Patients who developed ALS within 30 days of ventilator management initiation (ALS group) were compared with those who did not (non-ALS group).

RESULTS

Of the 105 patients, 14 (13%) developed ALS. The median positive-end expiratory pressure (PEEP) difference was 0.20 cmH₂O (95% confidence interval [CI], 0.20-0.20) and it was higher in the ALS group than in the non-ALS group (9.6 [7.8-20.2] vs. 9.3 [7.3-10.2], respectively). For peak pressure, the median difference was -0.30 cmH₂O (95% CI, -0.30 - -0.20) (20.4 [17.0-24.4] in the ALS group vs. 20.9 [16.7-24.6] in the non-ALS group). The mean pressure difference of 0.0 cmH₂O (95% CI, 0.0-0.0) (12.7 [10.9-14.6] vs. 13.0 [10.3-15.0], respectively) was also higher in the non-ALS group than in the ALS group. The difference in single ventilation volume per ideal body weight was 0.71 mL/kg (95% CI, 0.70-0.72) (8.17 [6.79-9.54] vs. 7.43 [6.03-8.81], respectively), and the difference in dynamic lung compliance was 8.27 mL/cmH₂O (95% CI, 12.76-21.95) (43.8 [28.2-68.8] vs. 35.7 [26.5-41.5], respectively); both were higher in the ALS group than in the non-ALS group.

CONCLUSIONS

There was no association between higher ventilator pressures and the development of ALS. The ALS group had higher dynamic lung compliance and tidal volumes than the non-ALS group, which may indicate a pulmonary contribution to ALS. Ventilator management that limits tidal volume may prevent ALS development.

Ultraprotective Ventilation via ECCO2R in Three Patients Presenting an Air Leak: Is ECCO2R Effective?

Extracorporeal CO₂ removal (ECCO2R) is a therapeutic approach that allows protective ventilation in acute respiratory failure by preventing hypercapnia and subsequent acidosis. The main indications for ECCO2R in acute respiratory failure are COPD (chronic obstructive pulmonary disease) exacerbation, acute respiratory distress syndrome (ARDS) and other situations of asthmatics status. However, CO₂ removal procedure is not extended to those ARDS patients presenting an air leak. Here, we report three cases of air leaks in patients with an ARDS that were successfully treated using a new ECCO2R device. Case 1 is a polytrauma patient that developed pneumothorax during the hospital stay, case 2 is a patient with a post-surgical bronchial fistula after an Ivor-Lewis esophagectomy, and case 3 is a COVID-19 patient who developed a spontaneous pneumothorax after being hospitalized for a prolonged time. ECCO2R allowed for protective ventilation mitigating VILI (ventilation-induced lung injury) and significantly improved hypercapnia and respiratory acidemia, allowing time for the native lung to heal. Although further investigation is needed, our observations seem to suggest that CO₂ removal can be a safe and effective procedure in patients connected to mechanical ventilation with ARDS-associated air leaks.

Time dependency and unique etiology of barotrauma in COVID-19: A retrospective cohort study with landmark analysis and pathological approach

BACKGROUND

Barotrauma frequently occurs in coronavirus disease 2019. Previous studies have reported barotrauma to be a mortality-risk factor; however, its time-dependent nature and pathophysiology are not elucidated. To investigate the time-dependent characteristics and the etiology of coronavirus disease 2019-related-barotrauma.

METHODS AND FINDINGS

We retrospectively reviewed intubated patients with coronavirus disease 2019 from March 2020 to May 2021. We compared the 90-day survival between the barotrauma and non-barotrauma groups and performed landmark analyses on days 7, 14, 21, and 28. Barotrauma within seven days before the landmark was defined as the exposure. Additionally, we evaluated surgically treated cases of coronavirus disease 2019-related pneumothorax. We included 192 patients. Barotrauma developed in 44 patients (22.9%). The barotrauma group's 90-day survival rate was significantly worse (47.7% vs. 82.4%, p < 0.001). In the 7-day landmark analysis, there was no significant difference (75.0% vs. 75.7%, p = 0.79). Contrastingly, in the 14-, 21-, and 28-day landmark analyses, the barotrauma group's survival rates were significantly worse (14-day: 41.7% vs. 69.1%, p = 0.044; 21-day: 16.7% vs. 62.5%, p = 0.014; 28-day: 20.0% vs. 66.7%, p = 0.018). Pathological examination revealed a subpleural hematoma and pulmonary cyst with heterogenous lung inflammation.

CONCLUSIONS

Barotrauma was a poor prognostic factor for coronavirus disease 2019, especially in the late phase. Heterogenous inflammation may be a key finding in its mechanism. Barotrauma is a potentially important sign of lung destruction.

Incidence and Outcome of Pneumomediastinum in Non-ICU Hospitalized COVID-19 Patients

OBJECTIVES

Pneumomediastinum (PNM) is a rare complication of mechanical ventilation, but its reported occurrence in patients with acute respiratory distress syndrome secondary to COVID-19 is significant. The objective is to determine the incidence, risk factors, and outcome of PNM in non-ICU hospitalized patients with severe-to-critical COVID-19 pneumonia.

DESIGN

Retrospective observational study.

SETTING

Population-based, single-setting, tertiary-care level COVID treatment center.

PATIENTS

Individuals hospitalized with a diagnosis of COVID-19 pneumonia and severe to critical illness were included. Those hospitalized without respiratory failure, observed for less than 24 hours, or admitted from an ICU were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

All patients underwent a complete clinical assessment and chest CT scan, and were followed up from hospitalization to discharge or death. The outcome was the number of cases of PNM, defined as the presence of free air in the mediastinal tissues diagnosed by chest CT scan, in non-ICU hospitalized patients and the subsequent risk of intubation and mortality. PNM occurred in 48 out of 331 participants. The incidence was 14.5% (95% CI, 10.9-18.8%). A CT-Scan Severity score greater than 15 was positively associated with PNM (odds ratio [OR], 4.09; p = 0.002) and was observed in 35.2% of the participants (95% CI, 26.2-44.9%). Noninvasive ventilation was also positively associated with PNM (OR, 4.46; p = 0.005), but there was no positive association with airway pressures. Fifty patients (15%) were intubated, and 88 (27%) died. Both the risk for intubation and mortality were higher in patients with PNM, with a hazard ratio of 3.72 ( p < 0.001) and 3.27 ( p < 0.001), respectively.

CONCLUSIONS

Non-ICU hospitalized patients with COVID-19 have a high incidence of PNM, increasing the risk for intubation and mortality three- to four-fold, particularly in those with extensive lung damage. These findings help define the risk and outcome of PNM in severe-to-critical COVID-19 pneumonia in a non-ICU setting.

Barotrauma in COVID 19: Incidence, pathophysiology, and effect on prognosis

Objectives

To investigate the incidence, risk factors, and outcomes of barotrauma (pneumomediastinum and subcutaneous emphysema) in mechanically ventilated COVID-19 patients. To describe the chest radiography patterns of barotrauma and understand the development in relation to mechanical ventilation and patient mortality.

Methods

We performed a retrospective study of 363 patients with COVID-19 from March 1 to April 8, 2020. Primary outcomes were pneumomediastinum or subcutaneous emphysema with or without pneumothorax, pneumoperitoneum, or pneumoretroperitoneum. The secondary outcomes were length of intubation and death. In patients with pneumomediastinum and/or subcutaneous emphysema, we conducted an imaging review to determine the timeline of barotrauma development.

Results

Forty three out of 363 (12%) patients developed barotrauma radiographically. The median time to development of either pneumomediastinum or subcutaneous emphysema was 2 days (IQR 1.0–4.5) after intubation and the median time to pneumothorax was 7 days (IQR 2.0–10.0). The overall incidence of pneumothorax was 28/363 (8%) with an incidence of 17/43 (40%) in the barotrauma cohort and 11/320 (3%) in those without barotrauma (p ≤ 0.001). In total, 257/363 (71%) patients died with an increase in mortality in those with barotrauma 33/43 (77%) vs. 224/320 (70%). When adjusting for covariates, barotrauma was associated with increased odds of death (OR 2.99, 95% CI 1.25–7.17).

Conclusion

Barotrauma is a frequent complication of mechanically ventilated COVID-19 patients. In comparison to intubated COVID-19 patients without barotrauma, there is a higher rate of pneumothorax and an increased risk of death.

Complications of invasive mechanical ventilation in critically Ill Covid-19 patients - A narrative review

Critically ill COVID-19 patients have to undergo positive pressure ventilation, a non-physiological and invasive intervention that can be lifesaving in severe ARDS. Similar to any other intervention, it has its pros and cons. Despite following Lung Protective Ventilation (LPV), some of the complications are frequently reported in these critically ill patients and significantly impact overall mortality. The complications related to invasive mechanical ventilation (IMV) in critically ill COVID-19 patients can be broadly divided into pulmonary and non-pulmonary. Among pulmonary complications, the most frequent is ventilator-associated pneumonia. Others are barotrauma, including subcutaneous emphysema, pneumomediastinum, pneumothorax, bullous lesions, cardiopulmonary effects of right ventricular dysfunction, and pulmonary complications mimicking cardiac failure, including pulmonary edema. Tracheal complications, including full-thickness tracheal lesions (FTTLs) and tracheoesophageal fistulas (TEFs) are serious but rare complications. Non-Pulmonary complications include neurological, nephrological, ocular, and oral complications.

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The complications related to IMV in critically ill covid 19 patients can be broadly divided into pulmonary and non-pulmonary complications.

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Among pulmonary complications the most frequent is Ventilator associated pneumonia.

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Others are Barotrauma, Cardiopulmonary effects of right ventricular dysfunction & Pulmonary complications mimicking cardiac failure including pulmonary edema, tracheal complications including full thickness tracheal lesions & tracheoesophageal fistulas.

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Non-Pulmonary complications of prolonged IMV include neurological, nephrological, ocular and oral complications.

Barotrauma and its complications in COVID-19 patients: a retrospective study at tertiary care hospital of Eastern India

BACKGROUND

The development of barotrauma in COVID-19 patients who were ventilated and admitted to the intensive treatment unit seemed to have been a problematic issue in the COVID era. This study aimed to explore the possibility of developing the barotrauma-related issues with mechanical ventilation in the cases of individuals suffering from COVID-19.

RESULTS

Out of 48 patients who developed barotrauma, 30 (62.5%) presented with pneumothorax, 22 (45.8%) with pneumomediastinum, 10 (20.8%) with subcutaneous emphysema, and 2 (4.1%) with pneumopericardium. Of those that developed barotrauma, 45 (93.7%) patients were in acute respiratory distress syndrome. In patients with and without barotrauma, significant factors were white blood cell count (p = 0.001), neutrophil percentage (p = 0.012), and lymphocyte percentage (p = 0.014). There were no statistically significant differences in CRP, procalcitonin, d-dimer test, LDH, or ferritin.

CONCLUSIONS

Patients infected with COVID-19 have a high risk of barotrauma when on mechanical ventilation. As a result, the death rate in this patient group is higher.

Clinical Profile of Patients with Severe Acute Respiratory Syndrome Coronavirus 2 Infection Developing Pulmonary Barotrauma on Mechanical Ventilation

Background

There is limited information on clinical profile and outcomes of patients on mechanical ventilation (MV) who developed pulmonary barotrauma (PBT) in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

Patients and methods

In a retrospective observational study, all SARS-CoV-2 pneumonia patients admitted from March 28, 2020, to August 31, 2020, at Sir HN Reliance Foundation Hospital and Research Center and Seven Hills Hospital (Reliance Facility), Mumbai, India, of 18 years and above on MV and developed PBT, were included.

Results

A total of 14 SARS-CoV-2 patients of 45 on MV (31.0%) developed PBT of 1,029 hospitalized. All patients were male and divided as per admission into PaO₂/FiO₂ (P/F) ≤100 (median 80) and P/F >100 (median 222) group. Pneumothorax developed in seven and six cases of P/F ≤100 and P/F >100 groups, respectively. Three patients in each group developed subcutaneous emphysema, while four developed pneumomediastinum in P/F >100 group. Twelve patients (7, P/F ≤100, and 5, P/F >100) were on invasive, while two (P/F >100) were on noninvasive MV. The mean P/F on the day of PBT was reduced by 27.5 and 65.3%, while peak inspiratory pressure was elevated with a median of 36 and 28 cm H₂O in P/F ≤100 and P/F >100 groups, respectively. The median highest tidal volume (420 mL), positive-end expiratory pressure (8 vs 6 cm H₂O) on the day of PBT, and length of hospital stay (11 vs 25 days) did not differ between two groups. Survival was 28.6% (4/14).

Conclusion

SARS-CoV-2 patients requiring MV with PBT had poor outcomes. Clinicians should be vigilant about the diagnosis of PBT.

How to cite this article

Kargirwar KV, Rathod D, Kumar V, Patel M, Shah M, Choudhury H, et al. Clinical Profile of Patients with Severe Acute Respiratory Syndrome Coronavirus 2 Infection Developing Pulmonary Barotrauma on Mechanical Ventilation. Indian J Crit Care Med 2022;26(5):613–618.

Clinical impact of pneumothorax in patients with Pneumocystis jirovecii pneumonia and respiratory failure in an HIV-negative cohort

Background

Pneumocystis jirovecii pneumonia (PCP) with acute respiratory failure can result in development of pneumothorax during treatment. This study aimed to identify the incidence and related factors of pneumothorax in patients with PCP and acute respiratory failure and to analyze their prognosis.

Methods

We retrospectively reviewed the occurrence of pneumothorax, including clinical characteristics and results of other examinations, in 119 non-human immunodeficiency virus patients with PCP and respiratory failure requiring mechanical ventilator treatment in a medical intensive care unit (ICU) at a tertiary-care center between July 2016 and April 2019.

Results

During follow up duration, twenty-two patients (18.5%) developed pneumothorax during ventilator treatment, with 45 (37.8%) eventually requiring a tracheostomy due to weaning failure. Cytomegalovirus co-infection (odds ratio 13.9; p = 0.013) was related with occurrence of pneumothorax in multivariate analysis. And development of pneumothorax was not associated with need for tracheostomy and mortality. Furthermore, analysis of survivor after 28 days in ICU, patients without pneumothorax were significantly more successful in weaning from mechanical ventilator than the patients with pneumothorax (44% vs. 13.3%, p = 0.037). PCP patients without pneumothorax showed successful home discharges compared to those who without pneumothorax (p = 0.010).

Conclusions

The development of pneumothorax increased in PCP patient with cytomegalovirus co-infection, pneumothorax might have difficulty in and prolonged weaning from mechanical ventilators, which clinicians should be aware of when planning treatment for such patients.

Design and simulation of mechanical ventilators

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

Outcomes of Barotrauma in Critically Ill COVID-19 Patients With Severe Pneumonia

Background:

Pneumomediastinum and pneumothorax are complications which may be associated with barotrauma in mechanically ventilated patients. The current literature demonstrates unclear outcomes regarding barotrauma in critically ill patients with severe COVID-19. The purpose of this study was to examine the incidence of barotrauma in patients with severe COVID-19 pneumonia and its influence on survival.

Study Design and Methods:

A retrospective cohort study was performed from March 18, 2020 to May 5, 2020, with follow-up through June 18, 2020, encompassing critically ill intubated patients admitted for COVID-19 pneumonia at an academic tertiary care hospital in Brooklyn, New York. Critically ill patients with pneumomediastinum, pneumothorax, or both (n = 75) were compared to those without evidence of barotrauma (n = 206). Clinical characteristics and short-term patient outcomes were analyzed.

Results:

Barotrauma occurred in 75/281 (26.7%) of included patients. On multivariable analysis, factors associated with increased 30-day mortality were elevated age (HR 1.015 [95% CI 1.004-1.027], P = 0.006), barotrauma (1.417 [1.040-1.931], P = 0.027), and renal dysfunction (1.602 [1.055-2.432], P = 0.027). Protective factors were administration of remdesivir (0.479 [0.321-0.714], P < 0.001) and receipt of steroids (0.488 [0.370-0.643], P < 0.001).

Conclusion:

Barotrauma occurred at high rates in intubated critically ill patients with COVID-19 pneumonia and was found to be an independent risk factor for 30-day mortality.

Serious complications in COVID-19 ARDS cases: pneumothorax, pneumomediastinum, subcutaneous emphysema and haemothorax

The novel coronavirus identified as severe acute respiratory syndrome-coronavirus-2 causes acute respiratory distress syndrome (ARDS). Our aim in this study is to assess the incidence of life-threatening complications like pneumothorax, haemothorax, pneumomediastinum and subcutaneous emphysema, probable risk factors and effect on mortality in coronavirus disease-2019 (COVID-19) ARDS patients treated with mechanical ventilation (MV). Data from 96 adult patients admitted to the intensive care unit with COVID-19 ARDS diagnosis from 11 March to 31 July 2020 were retrospectively assessed. A total of 75 patients abiding by the study criteria were divided into two groups as the group developing ventilator-related barotrauma (BG) (N = 10) and the group not developing ventilator-related barotrauma (NBG) (N = 65). In 10 patients (13%), barotrauma findings occurred 22 ± 3.6 days after the onset of symptoms. The mortality rate was 40% in the BG-group, while it was 29% in the NBG-group with no statistical difference identified. The BG-group had longer intensive care admission duration, duration of time in prone position and total MV duration, with higher max positive end-expiratory pressure (PEEP) levels and lower min pO₂/FiO₂ levels. The peak lactate dehydrogenase levels in blood were higher by statistically significant level in the BG-group (P < 0.05). The contribution of MV to alveolar injury caused by infection in COVID-19 ARDS patients may cause more frequent barotrauma compared to classic ARDS and this situation significantly increases the MV and intensive care admission durations of patients. In terms of reducing mortality and morbidity in these patients, MV treatment should be carefully maintained within the framework of lung-protective strategies and the studies researching barotrauma pathophysiology should be increased.

Case Report: Barotrauma in COVID-19 Case Series

Severe acute respiratory syndrome coronavirus 2 can cause pulmonary complications, such as increased risk of barotrauma (BT), but its prevalence and risk factors are not known. In this case series, the course of BT and its related risk factors were discussed in patients with COVID-19 who were admitted to the intensive care unit. Medical records of the patients with COVID-19 and BT and hospitalized in the intensive care unit for 5 months were extracted. The course of BT and its possible associated risk factors are descriptively presented. Among 103 patients with COVID-19 who were intubated, 13 patients (12.6%) had BT. One patient developed BT before intubation. All patients with BT were male. Half of them developed BT in the first 5 days of intubation. Eight patients (61.53%) had a positive culture for Klebsiella pneumoniae. Nine patients (69.9%) died. High positive end-expiratory pressure, coinfection with bacterial pneumonia, and history of lung disease may affect BT incidence. The treatment team should increase their upervision on the ventilator setting, especially in the first week of intubation.

Pneumomediastinum in COVID-19: A series of three cases and review of literature

Coronavirus disease-19 caused by severe acute respiratory syndrome Corona virus-2 is characterised by wide heterogeneity in clinical presentation. The typical radiographic findings in COVID-19 include bilateral ground-glass opacities and/or consolidations predominantly affecting the lower lobes and posterior segments of lungs. Other rare abnormal radiographic findings include pneumothorax, pneumomediastinum and pneumopericardium. There has been an increased incidence of pneumomediastinum, a rare but potentially life-threatening complication during this pandemic. It may be spontaneous or secondary. Pneumomediastinum may be due to barotrauma, cytokine storm induced diffuse alveolar injury or direct viral infection of type I and type II pneumocytes. The presence of pneumomediastinum in COVID-19 patients may indicate extensive alveolar membrane destruction and those patients need close monitoring. There are no consensus guidelines in managing COVID-19 patients with pneumomediastinum. Higher mortality rates (70.58%) are reported in intubated COVID-19 patients with pneumomediastinum. The development of pneumomediastinum in COVID-19 should be considered as a poor prognostic factor.

Prevalence and risk factors of barotrauma in Covid-19 patients admitted to an intensive care unit in Kuwait; a retrospective cohort study

BACKGROUND

The development of barotrauma has been suggested to complicate the management of mechanically ventilated COVID-19 patients admitted to the intensive care unit (ICU). This study aims to identify potential risk factors associated with the development of barotrauma related complications in COVID-19 patients receiving mechanical ventilation.

METHODS

A retrospective cohort study was carried out in a single COVID-19 designated center in Kuwait. Three hundred and forty-three confirmed COVID-19 patients transferred and/or admitted to our institution between February 26, 2020 and June 20, 2020 were included in the study. All patients were admitted into the ICU with the majority being mechanically ventilated (81.3%).

RESULTS

Fifty-four (15.4%) patients developed barotrauma, of which 49 (90.7%) presented with pneumothorax, and 14.8% and 3.7% due to pneumomediastinum and pneumopericardium respectively. Of those that developed barotrauma, 52 (96.3%) patients were in acute respiratory distress syndrome (ARDS). Biochemically, the white blood cells (p = 0.001), neutrophil percentage (p = 0.012), lymphocyte percentage (p = 0.014), neutrophil: lymphocyte ratio (NLR) (p=<0.001) and lactate dehydrogenase (LDH) (p = 0.002) were found to be significantly different in patients that developed barotrauma. Intubation due to low level of consciousness (p = 0.007), a high admission COVID-GRAM score (p = 0.042), and a positive-end expiratory pressure (PEEP) higher than the control group (p = 0.016) were identified as potential risk factors for the development of barotrauma.

CONCLUSION

Patients infected with COVID-19 have a significant risk of developing barotrauma when receiving invasive mechanical ventilation. This poses a substantial impact on the hospital course of the patients and clinical outcome, correlating to a higher mortality rate in this cohort of patients.

Incidence of Barotrauma in Patients With COVID-19 Pneumonia During Prolonged Invasive Mechanical Ventilation - A Case-Control Study

BACKGROUND

SARS-CoV2 can cause pulmonary failure requiring prolonged invasive mechanical ventilation (MV). Lung protective ventilation strategies are recommended in order to minimize ventilator induced lung injury. Whether patients with COVID-19 have the same risk for complications including barotrauma is still unknown. Therefore, we investigated barotrauma in patients with COVID-19 pneumonia requiring prolonged MV.

METHODS

All patients meeting diagnosis criteria for ARDS according to the Berlin Definition, with PCR positive SARS-CoV2 infection and prolonged mechanical ventilation, defined as ≥2 days, treated at our ARDS referral center between March and April 2020 were included in a retrospective registry analysis. Complications were detected by manual review of all patient data including respiratory data, imaging studies, and patient files.

RESULTS

A total of 20 patients with severe COVID-19 pulmonary failure (Overall characteristics: median age: 61 years, female gender 6, median duration of MV 22 days) were analyzed. Eight patients (40%) developed severe barotrauma during MV (after median 18 days, range: 1-32) including pneumothorax (5/20), pneumomediastinum (5/20), pneumopericard (1/20), and extended subcutaneous emphysema (5/20). Median respirator settings 24 hours before barotrauma were: Peak inspiratory pressure (Ppeak) 29 cm H2O (range: 27-35), positive end-expiratory pressure (PEEP) 14 cm H2O (range: 5-24), tidal volume (VT) 5.4ml/kg predicted body weight (range 0.4-8.6), plateau pressure (Pplateau) 27 cm H2O (range: 19-30). Mechanical ventilation was significantly more invasive on several occasions in patients without barotrauma.

CONCLUSION

Barotrauma in COVID-19 induced respiratory failure requiring mechanical ventilation was found in 40% of patients included in this registry. Our data suggest that barotrauma in COVID-19 may occur even when following recommendations for lung protective MV.

Fluid management in Acute Respiratory Distress Syndrome: A narrative review

Acute Respiratory Distress Syndrome remains a major source of morbidity and mortality in the modern intensive care unit (ICU). Major advances in the understanding and management of this condition were made in the last two decades. The use of low tidal ventilation is a well-established therapy. Conservative fluid management is now another cornerstone of management. However, much remains to be understood in this arena. Assessing volume status in these patients may be challenging and the tools available to do so are far from perfect. Several dynamic measures including pulse pressures variation are used. Ultrasound of the lungs and the vascular system may also have a role. In addition, the type of fluid to administer when needed is still open to debate. Finally, supportive measures in these patients, early during their ICU stay and later after discharge continue to be crucial for survival and adequate recovery.

Biomedical engineer's guide to the clinical aspects of intensive care mechanical ventilation

Background

Mechanical ventilation is an essential therapy to support critically ill respiratory failure patients. Current standards of care consist of generalised approaches, such as the use of positive end expiratory pressure to inspired oxygen fraction (PEEP–FiO₂) tables, which fail to account for the inter- and intra-patient variability between and within patients. The benefits of higher or lower tidal volume, PEEP, and other settings are highly debated and no consensus has been reached. Moreover, clinicians implicitly account for patient-specific factors such as disease condition and progression as they manually titrate ventilator settings. Hence, care is highly variable and potentially often non-optimal. These conditions create a situation that could benefit greatly from an engineered approach. The overall goal is a review of ventilation that is accessible to both clinicians and engineers, to bridge the divide between the two fields and enable collaboration to improve patient care and outcomes. This review does not take the form of a typical systematic review. Instead, it defines the standard terminology and introduces key clinical and biomedical measurements before introducing the key clinical studies and their influence in clinical practice which in turn flows into the needs and requirements around how biomedical engineering research can play a role in improving care. Given the significant clinical research to date and its impact on this complex area of care, this review thus provides a tutorial introduction around the review of the state of the art relevant to a biomedical engineering perspective.

Discussion

This review presents the significant clinical aspects and variables of ventilation management, the potential risks associated with suboptimal ventilation management, and a review of the major recent attempts to improve ventilation in the context of these variables. The unique aspect of this review is a focus on these key elements relevant to engineering new approaches. In particular, the need for ventilation strategies which consider, and directly account for, the significant differences in patient condition, disease etiology, and progression within patients is demonstrated with the subsequent requirement for optimal ventilation strategies to titrate for patient- and time-specific conditions.

Conclusion

Engineered, protective lung strategies that can directly account for and manage inter- and intra-patient variability thus offer great potential to improve both individual care, as well as cohort clinical outcomes.

The impact of obesity on pulmonary deterioration in patients undergoing robotic-assisted laparoscopic prostatectomy

Obesity affects respiratory and hemodynamic function in anesthetized patients. The aim of this study was to evaluate the influence of the body mass index (BMI) on pulmonary changes in a permanent 45° steep Trendelenburg position (STP) during robotic-assisted laparoscopic prostatectomy (RALP). 51 patients undergoing RALP under standardized anesthesia were included. Perioperative pulmonary function and oxygenation were measured in awake patients (T₀), 20 min after the induction of anesthesia (T₁), after insufflation of the abdomen in supine position (T₂), after 30 min in STP (T₃), when controlling Santorini's plexus in STP (T₄), before awakening while supine (T₅), and after 45 min in the recovery room (T₆). Patient-specific and time-dependent factor on ventilation and predicted peak inspiratory pressure (PIP), driving pressure (P_driv) and lung compliance (LC) in a linear regression model were calculated. PIP and P_driv increased significantly after induction of capnoperitoneum (T_2-4) (p < 0.0001). In univariate mixed effects models, BMI was found to be a significant predictor for PIP and P_driv increase and LC decrease. Obese patients a BMI > 31 kg/m² reached critical PIP values ≥ 35 cmH₂O. Postoperative oxygenation represented by the PaO₂/FiO₂ ratio was significantly decreased compared to T₀ (p < 0.0001). Obesity in combination with STP and capnoperitoneum during RALP has a profound effect on pulmonary function. Increased PIP and P_driv and decreased LC are directly correlated with a high BMI. Changes in PIP, P_driv and LC during RALP may be predicted in relation to patient's BMI for consideration in the preoperative setting. Trial registration number Z-2014-0387-6. Registered on 8 July 2014.

Compliance-guided versus FiO2-driven positive-end expiratory pressure in patients with moderate or severe acute respiratory distress syndrome according to the Berlin definition

OBJECTIVE

To study the effect of setting positive end-expiratory pressure (PEEP) in an individualized manner (based on highest static compliance) compared to setting PEEP according to FiO₂ upon mortality at 28 and 90 days, in patients with different severity acute respiratory distress syndrome (ARDS).

SETTING

A Spanish medical-surgical ICU.

DESIGN

A post hoc analysis of a randomized controlled pilot study.

PATIENTS

Patients with ARDS.

INTERVENTIONS

Ventilation with low tidal volumes and pressure limitation at 30cmH₂O, randomized in two groups according to the method used to set PEEP: FiO₂-guided PEEP group according to FiO₂ applied and compliance-guided group according to the highest compliance.

PRIMARY VARIABLES OF INTEREST

Demographic data, risk factors and severity of ARDS, APACHE II and SOFA scores, daily Lung Injury Score, ventilatory measurements, ICU and hospital stay, organ failure and mortality at day 28 and 90 after inclusion.

RESULTS

A total of 159 patients with ARDS were evaluated, but just 70 patients were included. Severe ARDS patients showed more organ dysfunction-free days at 28 days (12.83±10.70 versus 3.09±7.23; p=0.04) and at 90 days (6.73±22.31 vs. 54.17±42.14, p=0.03), and a trend toward lower 90-days mortality (33.3% vs. 90.9%, p=0.02), when PEEP was applied according to the best static compliance. Patients with moderate ARDS did not show these effects.

CONCLUSIONS

In patients with severe ARDS, individualized PEEP selection based on the best static compliance was associated to lower mortality at 90 days, with an increase in organ dysfunction-free days at 28 and 90 days.

Recommendations for Mechanical Ventilation during Donor Care

The organ procurement coordinator usually directs adjustments to the mechanical ventilator during donor care. It is often difficult to achieve optimal oxygen uptake and carbon dioxide removal while avoiding barotrauma or undesirable effects on the cardiac output. Interrelationships among a variety of ventilator parameters must be understood in order to achieve the desired goal of providing the best organs possible. These recommendations review the key ventilator parameters of tidal volume; positive end-expiratory pressure; auto–positive end-expiratory pressure; fraction of inspired oxygen; and flowrate and frequency and their interactions in controlling peak, plateau, and mean and end-expiratory airway pressures.

Prevalence and risk factors of pneumothorax among patients admitted to a Pediatric Intensive Care Unit

OBJECTIVE

Pneumothorax should be considered a medical emergency and requires a high index of suspicion and prompt recognition and intervention.

AIMS

The objective of the study was to evaluate cases developing pneumothorax following admission to a Pediatric Intensive Care Unit (PICU) over a 5-year period.

SETTINGS AND DESIGN

Case notes of all PICU patients (n = 1298) were reviewed, revealing that 135 cases (10.4%) developed pneumothorax, and these were compared with those patients who did not. The most common tool for diagnosis used was chest X-ray followed by a clinical examination.

SUBJECTS AND METHODS

Case notes of 1298 patients admitted in PICU over 1-year study.

RESULTS

Patients with pneumothorax had higher mortality rate (P < 0.001), longer length of stay (P < 0.001), higher need for mechanical ventilation (MV) (P < 0.001), and were of younger age (P < 0.001), lower body weight (P < 0.001), higher pediatric index of mortality 2 score on admission (P < 0.001), higher pediatric logistic organ dysfunction score (P < 0.001), compared to their counterpart. Iatrogenic pneumothorax (IP) represented 95% of episodes of pneumothorax. The most common causes of IP were barotrauma secondary to MV, central vein catheter insertion, and other (69.6%, 13.2%, and 17.2%, respectively). Compared to ventilated patients without pneumothorax, ventilated patients who developed pneumothorax had a longer duration of MV care (P < 0.001) and higher nonconventional and high-frequency oscillatory ventilation settings (P < 0.001).

CONCLUSIONS

This study demonstrated that pneumothorax is common in Alexandria University PICU patients, especially in those on MV and emphasized the importance of the strict application of protective lung strategies among ventilated patients to minimize the risk of pneumothorax.

Acute respiratory distress syndrome and pneumothorax

Acute respiratory distress syndrome (ARDS) can occur during the treatment of several diseases and in several interventional procedures as a complication. It is a difficult situation to handle and special care should be applied to the patients. Mechanical ventilation is used for these patients and several parameters are changed constantly until compliance is achieved. However, a complication that is observed during the application of positive airway pressure is pneumothorax. In our current work we will present definition and causes of pneumothorax in the setting of intensive care unit (ICU). We will identify differences and similarities of this situation and present treatment options.

[Pneumomediastinum: an aspect of pulmonary barotrauma during mechanical ventilation of acute respiratory distress syndrome]

Mechanical ventilation is a fundamental treatment of acute respiratory distress syndrome (ARDS). Despite compliance with the recommendations of protective mechanical ventilation, it can results in serious complications including the pulmonary barotrauma. This is often manifested by a pneumothorax. This observation describes an unusual aspect of barotrauma which is pneumomediastinum. The authors also point out the role of chest imaging in the management of mechanical ventilation during ARDS.

Impact of steroid medication before hospital admission on barotrauma in mechanically ventilated patients with acute respiratory distress syndrome in intensive care units

PURPOSE

To investigate the association between steroid medication before hospital admission and barotrauma in mechanically ventilated patients with acute respiratory distress syndrome (ARDS).

METHODS

An observational single-center retrospective study was conducted using patients admitted to the general intensive care unit (ICU) of a university hospital in Japan. We analyzed 149 mechanically ventilated patients with ARDS hospitalized between March 2008 and March 2011. ARDS was identified according to criteria from the Berlin Definition. Barotrauma was defined as pneumothorax, subcutaneous emphysema, or mediastinal emphysema occurring during mechanical ventilation in the ICU. The influence of steroid medication before hospital admission on barotrauma was studied using multiple logistic regression analysis.

RESULTS

There were no differences in baseline patient characteristics except for congestive heart failure, peak pressure during mechanical ventilation, and steroid pulse therapy between the barotrauma and non-barotrauma groups. Logistic regression analysis showed that peak pressure ≥35 cmH2O was associated with barotrauma in patients with ARDS [odds ratio (OR), 17.34; P < 0.01], whereas steroid medication before hospital admission was not a significant factor for barotrauma (OR, 1.63; P = 0.51).

CONCLUSIONS

Barotrauma in ARDS patients was associated with higher pressure during mechanical ventilation but not with steroid medication before hospital admission.

Iatrogenic pneumothorax related to mechanical ventilation

Pneumothorax is a potentially lethal complication associated with mechanical ventilation. Most of the patients with pneumothorax from mechanical ventilation have underlying lung diseases; pneumothorax is rare in intubated patients with normal lungs. Tension pneumothorax is more common in ventilated patients with prompt recognition and treatment of pneumothorax being important to minimize morbidity and mortality. Underlying lung diseases are associated with ventilator-related pneumothorax with pneumothoraces occurring most commonly during the early phase of mechanical ventilation. The diagnosis of pneumothorax in critical illness is established from the patients’ history, physical examination and radiological investigation, although the appearances of a pneumothorax on a supine radiograph may be different from the classic appearance on an erect radiograph. For this reason, ultrasonography is beneficial for excluding the diagnosis of pneumothorax. Respiration-dependent movement of the visceral pleura and lung surface with respect to the parietal pleura and chest wall can be easily visualized with transthoracic sonography given that the presence of air in the pleural space prevents sonographic visualization of visceral pleura movements. Mechanically ventilated patients with a pneumothorax require tube thoracostomy placement because of the high risk of tension pneumothorax. Small-bore catheters are now preferred in the majority of ventilated patients. Furthermore, if there are clinical signs of a tension pneumothorax, emergency needle decompression followed by tube thoracostomy is widely advocated. Patients with pneumothorax related to mechanical ventilation who have tension pneumothorax, a higher acute physiology and chronic health evaluation II score or PaO₂/FiO₂ < 200 mmHg were found to have higher mortality.

High versus low positive end-expiratory pressure (PEEP) levels for mechanically ventilated adult patients with acute lung injury and acute respiratory distress syndrome

BACKGROUND

Mortality in patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) remains high. These patients require mechanical ventilation, but this modality has been associated with ventilator-induced lung injury. High levels of positive end-expiratory pressure (PEEP) could reduce this condition and improve patient survival.

OBJECTIVES

To assess the benefits and harms of high versus low levels of PEEP in patients with ALI and ARDS.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2013, Issue 4), MEDLINE (1950 to May 2013), EMBASE (1982 to May 2013), LILACS (1982 to May 2013) and SCI (Science Citation Index). We used the Science Citation Index to find references that have cited the identified trials. We did not specifically conduct manual searches of abstracts of conference proceedings for this review. We also searched for ongoing trials (www.trialscentral.org; www.clinicaltrial.gov and www.controlled-trials.com).    

SELECTION CRITERIA

We included randomized controlled trials that compared the effects of two levels of PEEP in ALI and ARDS participants who were intubated and mechanically ventilated in intensive care for at least 24 hours.

DATA COLLECTION AND ANALYSIS

Two review authors assessed the trial quality and extracted data independently. We contacted investigators to identify additional published and unpublished studies. 

MAIN RESULTS

We included seven studies that compared high versus low levels of PEEP (2565 participants). In five of the studies (2417 participants), a comparison was made between high and low levels of PEEP with the same tidal volume in both groups, but in the remaining two studies (148 participants), the tidal volume was different between high- and low-level groups. We saw evidence of risk of bias in three studies, and the remaining studies fulfilled all criteria for adequate trial quality.In the main analysis, we assessed mortality occurring before hospital discharge only in those studies that compared high versus low PEEP with the same tidal volume in both groups. With the three studies that were included, the meta-analysis revealed no statistically significant differences between the two groups (relative risk (RR) 0.90, 95% confidence interval (CI) 0.81 to 1.01), nor was any statistically significant difference seen in the risk of barotrauma (RR 0.97, 95% CI 0.66 to 1.42). Oxygenation was improved in the high-PEEP group, although data derived from the studies showed a considerable degree of statistical heterogeneity. The number of ventilator-free days showed no significant difference between the two groups. Available data were insufficient to allow pooling of length of stay in the intensive care unit (ICU). The subgroup of participants with ARDS showed decreased mortality in the ICU, although it must be noted that in two of the three included studies, the authors used a protective ventilatory strategy involving a low tidal volume and high levels of PEEP.

AUTHORS' CONCLUSIONS

Available evidence indicates that high levels of PEEP, as compared with low levels, did not reduce mortality before hospital discharge. The data also show that high levels of PEEP produced no significant difference in the risk of barotrauma, but rather improved participants' oxygenation to the first, third, and seventh days. This review indicates that the included studies were characterized by clinical heterogeneity.  

Pneumomediastinum after retching

A 25-year-old woman with hirsutism presented to the Emergency Department of the medicine faculty in Gaziantep University with a 4-h History of dyspnoea, dysphagia, coughing, continuous and progressive chest pain radiating to the back and palpation of her neck. The physical examination was significant for diffuse neck and chest subcutaneous emphysema. The x-ray study and CT scan of the chest revealed pneumomediastinum. The patient reported that 6 h before presentation she took spironolactone due to hirsutism and she retched. Retching caused the symptoms. The patient was followed conservatively and fully recovered over the next 7 days. Spontaneous pneumomediastinum developed in this patient with no underlying lung disease, presumably from air leakage secondary to the excessive elevation of intrathoracic pressure due to retching. Pneumomediastinum is an uncommon disease arising most frequently and remains largely underdiagnosed clinically, especially in young, healthy patients.

Perioperative tidal volume and intra-operative open lung strategy in healthy lungs: where are we going?

Tidal volumes have tremendously decreased over the last decades from <15 ml kg(-1) to approximately 6 ml kg(-1) actual body weight. Guidelines, widely agreed and used, exist for patients with acute lung injury or acute respiratory distress syndrome (ARDS). However, it is questionable if data created in patients with acute lung injury or ARDS from ventilation on intensive care units can be transferred to healthy patients undergoing surgery. Consensus criteria regarding this topic are still missing because only a few randomised controlled trials have been performed to date, focussing on the use of the best intra-operative tidal volume. The same problem has been observed regarding the application of positive end-expiratory pressure (PEEP) and intra-operative lung recruitment. This article provides an overview of the current literature addressing the size of tidal volume, the use of PEEP and the application of the open-lung concept in patients without acute lung injury or ARDS. Pathophysiological aspects of mechanical ventilation are elucidated.

Pigtail catheter for the management of pneumothorax in mechanically ventilated patients

PURPOSE

There has been a paucity of data regarding the efficacy and safety of small-bore chest tubes (pigtail catheter) for the management of pneumothorax in mechanically ventilated patients.

METHODS

We conducted a retrospective review of mechanically ventilated patients who underwent pigtail catheter drainage as their initial therapy for pneumothorax in the emergency department and intensive care unit from January 2004 through January 2007 in a university hospital.

RESULTS

Among the 62 enrolled patients, there were 41 men (66%) and 21 women (34%), with a mean age of 63.8 +/- 20.3 years. A total of 70 episodes of pneumothoraces occurred in the intensive care unit, and 48 episodes of pneumothoraces (68.6%) were successfully treated with pigtail catheters. The average duration of pigtail drainage was 5.9 days (1-27 days). No major complications occurred through use of this procedure, except for pleural infections (n = 3, 4.2%) and clogged tube (n = 1, 1.4%). Comparing the variables between the success and failure of pigtail treatment, the failure group had a significantly higher proportion of Fio(2) >60% requirement (45.5% vs. 14.6%, P = .005) and higher positive end-expiratory pressure levels (8.7 +/- 3.0 vs. 6.2+/- 2.3 mm Hg, P = .001) at the time of pneumothorax onset than the success group. Further comparing the efficacy of pigtail drainage between barotraumas and iatrogenic pneumothorax, pigtail catheters for management of iatrogenic pneumothorax had a significantly higher success rate than barotraumas (87.5% vs. 43.3%, P < .0001).

CONCLUSION

Pigtail catheter drainage is relatively effective in treating iatrogenic but less promising for barotraumatic pneumothoraces.

Advances in extracorporeal ventilation

Mechanical ventilation remains the signature tool of critical care; however, within the past decade, a growing body of evidence suggests that positive pressure ventilation in acute respiratory failure is a double-edged sword that is associated with life-threatening complications such as nosocomial pneumonia and low cardiac performance. Essentially, solutions are required to provide adequate gas exchange and stable acid-base status while optimizing and maximizing pulmonary as well as remote organ protection. Recently, the first commercially available extracorporeal membrane ventilator was approved for clinical lung support, the Interventional Lung Assist. This article gives an overview of the potential indications for this device and the current clinical evidence in extracorporeal ventilation.

Real-time detection of pneumothorax using electrical impedance tomography

OBJECTIVES

Pneumothorax is a frequent complication during mechanical ventilation. Electrical impedance tomography (EIT) is a noninvasive tool that allows real-time imaging of regional ventilation. The purpose of this study was to 1) identify characteristic changes in the EIT signals associated with pneumothoraces; 2) develop and fine-tune an algorithm for their automatic detection; and 3) prospectively evaluate this algorithm for its sensitivity and specificity in detecting pneumothoraces in real time.

DESIGN

Prospective controlled laboratory animal investigation.

SETTING

Experimental Pulmonology Laboratory of the University of São Paulo.

SUBJECTS

Thirty-nine anesthetized mechanically ventilated supine pigs (31.0 +/- 3.2 kg, mean +/- SD).

INTERVENTIONS

In a first group of 18 animals monitored by EIT, we either injected progressive amounts of air (from 20 to 500 mL) through chest tubes or applied large positive end-expiratory pressure (PEEP) increments to simulate extreme lung overdistension. This first data set was used to calibrate an EIT-based pneumothorax detection algorithm. Subsequently, we evaluated the real-time performance of the detection algorithm in 21 additional animals (with normal or preinjured lungs), submitted to multiple ventilatory interventions or traumatic punctures of the lung.

MEASUREMENTS AND MAIN RESULTS

Primary EIT relative images were acquired online (50 images/sec) and processed according to a few imaging-analysis routines running automatically and in parallel. Pneumothoraces as small as 20 mL could be detected with a sensitivity of 100% and specificity 95% and could be easily distinguished from parenchymal overdistension induced by PEEP or recruiting maneuvers. Their location was correctly identified in all cases, with a total delay of only three respiratory cycles.

CONCLUSIONS

We created an EIT-based algorithm capable of detecting early signs of pneumothoraces in high-risk situations, which also identifies its location. It requires that the pneumothorax occurs or enlarges at least minimally during the monitoring period. Such detection was operator-free and in quasi real-time, opening opportunities for improving patient safety during mechanical ventilation.

Acute lung injury and the acute respiratory distress syndrome: a clinical review

Acute respiratory distress syndrome and acute lung injury are well defined and readily recognised clinical disorders caused by many clinical insults to the lung or because of predispositions to lung injury. That this process is common in intensive care is well established. The mainstay of treatment for this disorder is provision of excellent supportive care since these patients are critically ill and frequently have coexisting conditions including sepsis and multiple organ failure. Refinements in ventilator and fluid management supported by data from prospective randomised trials have increased the methods available to effectively manage this disorder.

Lung protective ventilatory strategies in acute lung injury and acute respiratory distress syndrome: from experimental findings to clinical application

This review addresses the physiological background and the current status of evidence regarding ventilator-induced lung injury and lung protective strategies. Lung protective ventilatory strategies have been shown to reduce mortality from adult respiratory distress syndrome (ARDS). We review the latest knowledge on the progression of lung injury by mechanical ventilation and correlate the findings of experimental work with results from clinical studies. We describe the experimental and clinical evidence of the effect of lung protective ventilatory strategies and open lung strategies on the progression of lung injury and current controversies surrounding these subjects. We describe a rational strategy, the open lung strategy, to accomplish an open lung, which may further prevent injury caused by mechanical ventilation. Finally, the clinician is offered directions on lung protective ventilation in the early phase of ARDS which can be applied on the intensive care unit.

Indications, management, and outcome of long-term positive-pressure ventilation in dogs and cats: 148 cases (1990-2001)

OBJECTIVE

To determine outcome of positive-pressure ventilation (PPV) for 24 hours or longer and identify factors associated with successful weaning from PPV and survival to hospital discharge in dogs and cats.

DESIGN

Retrospective case series.

ANIMALS

124 dogs and 24 cats that received PPV for 24 hours or longer.

PROCEDURES

Medical records were reviewed for signalment, primary diagnosis, reason for initiating PPV, measures of oxygenation and ventilation before and during PPV, ventilator settings, complications, duration of PPV, and outcome. Animals were categorized into 1 of 3 groups on the basis of the reason for PPV.

RESULTS

Group 1 patients received PPV for inadequate oxygenation (67 dogs and 6 cats), group 2 for inadequate ventilation (46 dogs and 16 cats), and group 3 for inadequate oxygenation and ventilation (11 dogs and 2 cats). Of the group 1 animals, 36% (26/73) were weaned from PPV and 22% (16/73) survived to hospital discharge. In group 2, 50% (31/62) were weaned from PPV and 39% (24/62) survived to hospital discharge. In group 3, 3 of 13 were weaned from PPV and 1 of 13 survived to hospital discharge. Likelihood of successful weaning and survival to hospital discharge were significantly higher for group 2 animals, and cats had a significantly lower likelihood of successful weaning from PPV, compared with dogs. Median duration of PPV was 48 hours (range, 24 to 356 hours) and was not associated with outcome.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that long-term PPV is practical and successful in dogs and cats.

Severe respiratory failure: advanced treatment options

BACKGROUND

Severe respiratory failure (including acute lung injury and acute respiratory distress syndrome) continues to be associated with significant mortality and morbidity in patients of all ages.

OBJECTIVE

To review the laboratory and clinical data in support of and future directions for the advanced treatment of severe respiratory failure.

DATA SOURCES

MEDLINE/PubMed search of all relevant primary and review articles.

DATA SYNTHESIS

Our understanding of lung pathophysiology and the role of ventilator-induced lung injury through basic science investigation has led to advances in lung protective strategies for the mechanical ventilation support of patients with severe respiratory failure. Specific modalities reviewed include low-tidal volume ventilation, permissive hypercapnia, the open lung approach, recruitment maneuvers, airway pressure release ventilation, high-frequency oscillatory ventilation, prone positioning, and extracorporeal life support. The pharmacologic strategies (including corticosteroids, surfactant, and nitric oxide) investigated for the treatment of severe respiratory failure are also reviewed.

CONCLUSION

In patients with severe respiratory failure, an incremental approach to the management of severe hypoxemia requires implementation of the strategies reviewed, with knowledge of the evidence base to support these strategies.