Surgical Critical Care and Emergency Surgery. Группа авторов

PMID: 31362770; PMCID: PMC6668078.

      15 A 40‐year‐old man with severe influenza‐induced ARDS is placed on venovenous ECMO via left and right common femoral veins. He requires ECMO for 12 days, and throughout his course is maintained on a continuous heparin infusion with an average activated partial thromboplastin time (aPTT) of 60 seconds. He is successfully decannulated after improvement in lung function, and then maintained on a continuous heparin infusion for 48 hours after decannulation. Two days after decannulation the patient has sudden‐onset tachycardia, hypoxemia, and hypotension. There is no change in the physical exam, respiratory mechanics, or chest x‐ray. What is the next most appropriate step?Discontinue heparin as the patient may be bleeding from the cannulation sites.Perform a transthoracic echocardiogram and consider CT chest to evaluate for a pulmonary embolism.Place bilateral chest tubes.Make the patient DNR after a family meeting.Perform an emergent bronchoscopy.Venous thromboembolism is a very common complication after venovenous ECMO. It occurs in 30–50% of patients after decannulation, even despite appropriate anticoagulation. Pulmonary embolism should be high on every clinicians’ differential diagnosis and should be ruled out and must be suspected and potentially treated.Other causes of respiratory failure to include pneumothorax, worsening lung function, or mucous plugging are also common in patients recovering from severe lung disease and must be ruled out as well with physical exam, observation of respiratory mechanics, and chest x‐ray.Goals of care discussions are always valuable in the management of critically ill patients; however, in the young, recovering patient, a family meeting to address DNR status is probably premature.Answer: BTrudzinski FC, Minko P, Rapp D, et al. Runtime and aPTT predict venous thrombosis and thromboembolism in patients on extracorporeal membrane oxygenation: a retrospective analysis. Ann Intensive Care. 2016; 6(1):66. doi: https://doi.org/10.1186/s13613‐016‐0172‐2. Epub 2016 Jul 19. PMID: 27432243; PMCID: PMC4949188.

      16 Which of the following is the strongest clinical indication to discontinue ECMO support?A patient is intubated for 16 days and requires a tracheostomy procedure.Arterial blood gas demonstrates a pH of 7.36 and a PaCO2 of 55 mm Hg on a sweep gas flow of 4 L/min.The patient has been on ECMO for 2 weeks.The patient is oozing blood from a left chest tube site and right femoral cannulation site.The patient has an SpO2 of 96% and arterial PaCO2 of 40 mm Hg on 0 L/min of VV ECMO sweep gas flow and low ventilator settings.As a rule of thumb, when extracorporeal support provides less than 30% of native cardiac or lung function, a trial off ECMO is indicated. If SpO2 > 95%, and arterial PaCO2 is < 50mm Hg for > 60 min off of sweep flow, decannulation from VV ECMO is reasonable. Patients with an elevated PaCO2 despite moderate sweep gas flow are likely not ready for a trial off ECMO.The need for a surgical procedure alone is not an indication for decannulation. In some cases, ECMO is indicated to provide additional support to patients undergoing high‐risk surgical procedures (such as complex airway or tracheal reconstructions or resections of anterior mediastinal masses). Additionally, prolonged duration of ECMO support should not be an isolated reason for decannulation.A small amount of oozing from surgical sites is not uncommon in ECMO patients. Premature decannulation may be considered only in rare cases of uncontrollable bleeding.Answer: EELSO Guidelines for Cardiopulmonary Extracorporeal Life Support (2017). Extracorporeal Life Support Organization, Version 1. Ann Arbor, MI, USA. www.elso.org (accessed 4 August 2017).

      17 A 35‐year‐old woman suffering from COVID‐19 is decannulated from venovenous (VV) ECMO after 12 days. She remains on the ventilator and in the ECMO ICU. The family is asking what they can expect for her post‐ECMO course. Which statement is most accurate?Approximately 40% of patients who are decannulated from ECMO will ultimately die in the hospital.She will require more sedation and higher ventilator settings in the coming days.Approximately 40% of patients will suffer from a DVT post‐ECMO decannulation.Prior ECMO cannulation is a contraindication to future ECMO cannulation.Physical therapy is contraindicated in the week post‐ECMO for fear of cannula site bleeding.The survival‐to‐discharge for all‐comers in respiratory failure ECMO is approximately 60%, though this rate continues to improve year‐to‐year with improvements in ICU care and device technology; while the survival‐to‐discharge for cardiac failure ECMO is approximately 53%. Though data is limited and premature, the survival‐to‐discharge of ECMO patients with COVID‐19 is 54%. While these survival rates are all encompassing and have been gathered over several decades, there are several prediction tools to attempt to elucidate anticipated survival for the individual patient; one of which is the RESP score. This model uses data points including age, duration of mechanical ventilation, immunocompromised status, among several other patient‐specific data points.Except in cases of severe device‐related complications, patients decannulated from ECMO should be adequately and safely maintained on an amount of support that allows for expedient recovery, re‐conditioning, and physical therapy. If it is anticipated that a patient requires neuromuscular blockade, increased sedation, and increased ventilator settings, then they should not be decannulated. The in‐hospital mortality after ECMO decannulation is approximately 10%. In select cases, patients who were decannulated from ECMO may require a second ECMO run, and this is within reason.Approximately 30–50% of patients decannulated from VV ECMO will suffer from a DVT, and screening for DVT is typically performed 48–72 hours post‐ECMO decannulation.Answer: CELSO Guidelines for Cardiopulmonary Extracorporeal Life Support (2017). Extracorporeal Life Support Organization, Version 1. Ann Arbor, MI, USA. www.elso.org (accessed 4 August 2017).Trudzinski FC, Minko P, Rapp D, et al. Runtime and aPTT predict venous thrombosis and thromboembolism in patients on extracorporeal membrane oxygenation: a retrospective analysis. Ann Intensive Care. 2016; 6(1):66. doi: https://doi.org/10.1186/s13613‐016‐0172‐2. Epub 2016 Jul 19. PMID: 27432243; PMCID: PMC4949188.Schmidt M, Bailey M, Sheldrake J, et al. Predicting survival after extracorporeal membrane oxygenation for severe acute respiratory failure. The Respiratory Extracorporeal Membrane Oxygenation Survival Prediction (RESP) score. Am J Respir Crit Care Med. 2014; 189(11):1374–82.

      18 A 6‐year‐old previously healthy girl is admitted to the PICU after being involved in a house fire resulting in acute respiratory distress with severe hypoxemic respiratory failure. Which of the following would indicate a need for venovenous ECMO in this patient?PaO2/FiO2 > 100–150Oxygenation index (OI) > 40Mean airway pressure > 15 cmH2O on high‐frequency oscillatory ventilationMean airway pressure > 15 cmH2O on conventional ventilationCarboxyhemoglobin level of 10%When evaluating a patient’s candidacy for extracorporeal support, the provider must consider the underlying pathology, the adequacy of gas exchange given the current mechanical ventilatory requirement, and the success/failure of adjunctive rescue therapies. Although significant variability in institutional protocols exists, salvage therapies for children on a conventional ventilator with mean airway pressure (MAP) > 20–25 cm H2O includes use of high‐frequency oscillatory ventilation (HFOV), nitric oxide, and prone positioning. MAP < 30 cm H2O are tolerable while on HFOV. The PaO2/FiO2 is the ratio of arterial oxygen partial pressure to fractional inspired oxygen and is a clinical indicator of hypoxemia (normal PaO2/FiO2 > 300). An alternative measure of oxygenation is the oxygenation index (OI), which is calculated as the reciprocal of the PaO2/FiO2 times 100 times the mean airway pressure: Severe respiratory failure as evidence by a sustained PaO2/FiO2 < 60–80 or OI > 40 predict high mortality and indicate a need for lung rescue with ECMO. For example, if the patient’s PaO2 were 60 mm Hg on an FiO2 of 1 and MAP of 30 cm H20, the OI would be 50, which is a strong indication for ECMO initiation in the pediatric population.Answer: BMaratta C, Potera RM, van Leeuwen G, et al. Extracorporeal Life Support Organization (ELSO): 2020 pediatric respiratory ELSO guideline. ASAIO J Am Soc Artif Intern Organs 1992. 2020; 66(9):975–979. doi: https://doi.org/10.1097/MAT.0000000000001223Zabrocki LA, Brogan TV, Statler KD, et al. Extracorporeal membrane oxygenation for pediatric respiratory failure: survival and predictors of mortality. Crit Care Med. 2011; 39(2):364–370. doi: https://doi.org/10.1097/CCM.0b013e3181fb7b35

      19 A newborn male infant with a fetal diagnosis of congenital diaphragmatic hernia (CDH) is admitted to the neonatal intensive