Use of Extracorporeal Membrane Oxygenation for Major Cardiopulmonary Resections.

BACKGROUND: In thoracic surgery, utilization of extracorporeal membrane oxygenation (ECMO) is mainly established for patients undergoing lung transplantation. The aim of our study was to summarize our single-center experience with intraoperative use of veno-venous- or veno-arterial-ECMO in patients undergoing complex lung surgery involving the main carina, or the left atrium or the descending aorta. METHODS: A total of 24 patients underwent combined complex lung, carinal, aortal, or left atrial resections. In cases of carinal resection, percutaneous veno-venous, jugular-femoral cannulation was considered suitable. For combined resection of lung and descending aorta, a percutaneous femoral veno-arterial cannulation was used. In cases of extended left atrial resection, a percutaneous jugular-femoral veno-venous-arterial cannulation was favored. RESULTS: Procedures were divided into three groups: carinal resections and reconstruction (n = 8), resections of the descending aorta and left lung (n = 7), resections of lung and left atrium (n = 9). No intraoperative complications occurred. Overall 30-day mortality was 25%. A complete resection was achieved in 18 patients. Median survival was 12 months. One- and 5-year survival were 48.1 and 22.7%, respectively. CONCLUSION: The present study shows that intraoperative use of ECMO for extended carinal, aortic, or atrial resections is feasible with minimal intraoperative complications allowing surgeons increased operating-field safety. Perioperative mortality is high, but this is rather an attribute of local extended disease and patient comorbidities.

Control of respiratory drive by extracorporeal CO2 removal in acute exacerbation of COPD breathing on non-invasive NAVA.

BACKGROUND: Veno-venous extracorporeal CO2 removal (vv-ECCO2R) and non-invasive neurally adjusted ventilator assist (NIV-NAVA) are two promising techniques which may prevent complications related to prolonged invasive mechanical ventilation in patients with acute exacerbation of COPD. METHODS: A physiological study of the electrical activity of the diaphragm (Edi) response was conducted with varying degrees of extracorporeal CO2 removal to control the respiratory drive in patients with severe acute exacerbation of COPD breathing on NIV-NAVA. RESULTS: Twenty COPD patients (SAPS II 37 ± 5.6, age 57 ± 9 years) treated with vv-ECCO2R and supported by NIV-NAVA were studied during stepwise weaning of vv-ECCO2R. Based on dyspnea, tolerance, and blood gases, weaning from vv-ECCO2R was successful in 12 and failed in eight patients. Respiratory drive (measured via the Edi) increased to 19 ± 10 µV vs. 56 ± 20 µV in the successful and unsuccessful weaning groups, respectively, resulting in all patients keeping their CO2 and pH values stable. Edi was the best predictor for vv-ECCO2R weaning failure (ROC analysis AUC 0.95), whereas respiratory rate, rapid shallow breathing index, and tidal volume had lower predictive values. Eventually, 19 patients were discharged home, while one patient died. Mortality at 90 days and 180 days was 15 and 25%, respectively. CONCLUSIONS: This study demonstrates for the first time the usefulness of the Edi signal to monitor and guide patients with severe acute exacerbation of COPD on vv-ECCO2R and NIV-NAVA. The Edi during vv-ECCO2R weaning was found to be the best predictor of tolerance to removing vv-ECCO2R.

Respiratory acidosis during bronchoscopy-guided percutaneous dilatational tracheostomy: impact of ventilator settings and endotracheal tube size.

BACKGROUND: The current study investigates the effect of bronchoscopy-guided percutaneous dilatational tracheostomy (PDT) on the evolution of respiratory acidosis depending on endotracheal tube (ET) sizes. In addition, the impact of increasing tidal volumes during the intervention was investigated. METHODS: Two groups of ICU-patients undergoing bronchoscopy-guided PDT with varying tidal volumes and tube sizes were consecutively investigated: 6 ml/kg (N = 29, mean age 57.4 ± 14.5 years) and 12 ml/kg predicted body weight (N = 34, mean age 59.5 ± 12.8 years). RESULTS: The mean intervention time during all procedures was 10 ± 3 min. The combination of low tidal volumes and ETs of 7.5 mm internal diameter resulted in the most profound increase in PaCO2 (32.2 ± 11.6 mmHg) and decrease in pH-value (- 0.18 ± 0.05). In contrast, the combination of high tidal volumes and ETs of 8.5 mm internal diameter resulted in the least profound increase in PaCO2 (8.8 ± 9.0 mmHg) and decrease of pH (- 0.05 ± 0.04). The intervention-related increase in PaCO2 was significantly lower when using higher tidal volumes for larger ET: internal diameter 7.5, 8.0 and 8.5: P > 0.05, =0.006 and = 0.002, respectively. Transcutaneous PCO2 monitoring revealed steadily worsening hypercapnia during the intervention with a high correlation of 0.87 and a low bias of 0.7 ± 9.4 mmHg according to the Bland-Altman analysis when compared to PaCO2 measurements. CONCLUSIONS: Profound respiratory acidosis following bronchoscopy-guided PDT evolves in a rapid and dynamic process. Increasing the tidal volume from 6 to 12 ml/kg PBW was capable of attenuating the evolution of respiratory acidosis, but this effect was only evident when using larger ETs. TRIAL REGISTRATION: DRKS00011004 . Registered 20th September 2016.

Regional expiratory time constants in severe respiratory failure estimated by electrical impedance tomography: a feasibility study.

BACKGROUND: Electrical impedance tomography (EIT) has been used to guide mechanical ventilation in ICU patients with lung collapse. Its use in patients with obstructive pulmonary diseases has been rare since obstructions could not be monitored on a regional level at the bedside. The current study therefore determines breath-by-breath regional expiratory time constants in intubated patients with chronic obstructive pulmonary disease (COPD) and acute respiratory distress syndrome (ARDS). METHODS: Expiratory time constants calculated from the global impedance EIT signal were compared to the pneumatic volume signals measured with an electronic pneumotachograph. EIT-derived expiratory time constants were additionally determined on a regional and pixelwise level. However, regional EIT signals on a single pixel level could in principle not be compared with similar pneumatic changes since these measurements cannot be obtained in patients. For this study, EIT measurements were conducted in 14 intubated patients (mean Simplified Acute Physiology Score II (SAPS II) 35 ± 10, mean time on invasive mechanical ventilation 36 ± 26 days) under four different positive end-expiratory pressure (PEEP) levels ranging from 10 to 17 cmH2O. Only patients with moderate-severe ARDS or COPD exacerbation were included into the study, preferentally within the first days following intubation. RESULTS: Spearman's correlation coefficient for comparison between EIT-derived time constants and those from flow/volume curves was between 0.78 for tau (τ) calculated from the global impedance signal up to 0.83 for the mean of all pixelwise calculated regional impedance changes over the entire PEEP range. Furthermore, Bland-Altman analysis revealed a corresponding bias of 0.02 and 0.14 s within the limits of agreement ranging from - 0.50 to 0.65 s for the aforementioned calculation methods. In addition, exemplarily in patients with moderate-severe ARDS or COPD exacerbation, different PEEP levels were shown to have an influence on the distribution pattern of regional time constants. CONCLUSIONS: EIT-based determination of breath-by-breath regional expiratory time constants is technically feasible, reliable and valid in invasively ventilated patients with severe respiratory failure and provides a promising tool to individually adjust mechanical ventilation in response to the patterns of regional airflow obstruction. TRIAL REGISTRATION: German Trial Register DRKS 00011650 , registered 01/31/17.

Development of the Diaphragmatic Paralysis Questionnaire: a simple tool for patient relevant outcome.

OBJECTIVES: Measurement tools of health-related quality of life (HRQL) that are specific for the underlying disorder are inevitably needed to assess HRQL changes following specific treatment strategies. The aim of the current study was to develop a questionnaire assessing HRQL in patients with unilateral diaphragmatic paresis. METHODS: Firstly, topics of health impairments covering physical, psychological, social and functional aspects were predefined by a physician expert panel to ensure face validity. Secondly, all predefined topics were rated by a patient group with unilateral diaphragmatic paresis (untreated: n = 11; postoperative: n = 9) using a 5-point Likert scale ranging from 'not relevant at all' (-2) to 'absolutely relevant' (+2) to guarantee content validity. Thirdly, only relevant topics (0 to +2) were used for item development, while non-relevant items (<0) were not subject for item development. RESULTS: In total, 20 patients rated a total of 43 topics covering a broad spectrum of health impairment. 21 were considered as relevant for item development. Items are answered on a 5-point Likert scale ranging from 'completely untrue' (-2) to 'always true' (+2). The Diaphragmatic Paralysis Questionnaire (DPQ) Summary Score ranges from 0 (worst HRQL) to 100 (best HRQL). Finally, the German DPQ was professionally translated and transculturally adapted into English, Italian, Dutch, French, Greek and Spanish, using translation/back-translation procedures. CONCLUSIONS: The DPQ is the first diseases-specific HRQL measure developed for patients with diaphragmatic paresis. In addition, the DPQ is available in 7 languages free of charge for non-profit purposes. CLINICAL TRIAL REGISTRATION: German clinical trials register: DRKS00017056.

Safety and Efficacy of a Novel Pneumatically Driven Extracorporeal Membrane Oxygenation Device.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is rapidly becoming a mainstream technology for lung or heart/lung support. Current ECMO devices mostly consist of a power-driven centrifugal pump and a dedicated oxygenator. We studied the safety and efficacy of a novel, fully pneumatically driven ECMO device, which could be used in both venovenous or venoarterial mode in an animal model. METHODS: Six healthy, awake sheep were treated with the Mobybox ECMO device (Hemovent, Aachen, Germany) over a 7-day period in a venovenous mode. Gas exchange, coagulation parameters, and safety were assessed. RESULTS: Using a blood flow rate of 2 L/min and a low sweep gas flow rate of 0.3 L/min, the PCO2 ranged from 38 to 44 mm Hg pre oxygenator and dropped to 32 to 36 mm Hg post oxygenator, whereas the PaO2 post oxygenator increased to 600 mm Hg. Higher levels of sweep gas flow resulted in cessation of spontaneous breathing in some animals, consistent with high-efficiency carbon dioxide removal; thus, the sweep gas flow rate was maintained at a low level. Platelets dropped from 177 ± 53/µL to 107 ± 28/µL on day 2, while returning to baseline by day 7 (180 ± 51/µL). Plasma-free hemoglobin remained low (2-9 mg/dL), whereas fibrinogen slightly increased, and then remained stable throughout the period. Neither the pump nor the oxygenator showed any visible clotting after 7 days. CONCLUSIONS: The pneumatically driven ECMO device provided excellent safety and physiologic efficacy in a 7-day sheep experiment without visible clotting, hemolysis, or sustained reductions in fibrinogen or platelets.

[Evolving Epidemiology of Home Mechanical Ventilation: A Rapidly Growing Challenge for Patient Care]. / Epidemiologische Entwicklung der außerklinischen Beatmung: Eine rasant zunehmende Herausforderung für die ambulante und stationäre Patientenversorgung.

BACKGROUND: Home mechanical ventilation is dramatically evolving in Germany. Patients with non-invasive and invasive ventilation are increasingly treated at home. In-hospital treatment of these patients is also necessary either for control visits or the management of acute medical problems. However, the development of in-hospital patient care, morbidity and mortality of these patients is unknown. METHODS: All patients with long-term dependence on mechanical ventilation for more than three months requiring hospitalisation between 2006 and 2016 were analysed (data obtained from the Federal Statistical Office of Germany). RESULTS: There was an exponential increase in the number of in-patients with long-term dependence of mechanical ventilation. While 24 845 patients were treated in-hospital in 2006, 86 117 patients were treated in 2016. Correspondingly, mortality decreased from 13.2 % (2006) to 5.7 % (2016). In addition, in 2016 47 % of all patients were treated on the intensive care or high dependency care unit. Overall, patients had been severely ill, as there were plenty of medical and neurological co-morbidities. The most common diagnosis was COPD with 58 % of all cases, followed by several cardiology diagnosis. A high number of patients had an impairment of renal function (24 %), in part requiring dialysis. CONCLUSIONS: The rapid development of home mechanical ventilation substantially impacts on the development of the hospital landscape in Germany. The exponential increase of these care-intensive patients is challenging for the health care system and requires a discussion about its limits.

Impact of sweep gas flow on extracorporeal CO2 removal (ECCO2R).

BACKGROUND: Veno-venous extracorporeal carbon dioxide (CO2) removal (vv-ECCO2R) is increasingly being used in the setting of acute respiratory failure. Blood flow rates range in clinical practice from 200 mL/min to more than 1500 mL/min, and sweep gas flow rates range from less than 1 to more than 10 L/min. The present porcine model study was aimed at determining the impact of varying sweep gas flow rates on CO2 removal under different blood flow conditions and membrane lung surface areas. METHODS: Two different membrane lungs, with surface areas of 0.4 and 0.8m2, were used in nine pigs with experimentally-induced hypercapnia. During each experiment, the blood flow was increased stepwise from 300 to 900 mL/min, with further increases up to 1800 mL/min with the larger membrane lung in steps of 300 mL/min. Sweep gas was titrated under each condition from 2 to 8 L/min in steps of 2 L/min. Extracorporeal CO2 elimination was normalized to a PaCO2 of 45 mmHg before the membrane lung. RESULTS: Reversal of hypercapnia was only feasible when blood flow rates above 900 mL/min were used with a membrane lung surface area of at least 0.8m2. The membrane lung with a surface of 0.4m2 allowed a maximum normalized CO2 elimination rate of 41 ± 6 mL/min with 8 L/min sweep gas flow and 900 mL blood flow/min. The increase in sweep gas flow from 2 to 8 L/min increased normalized CO2 elimination from 35 ± 5 to 41 ± 6 with 900 mL blood flow/min, whereas with lower blood flow rates, any increase was less effective, levelling out at 4 L sweep gas flow/min. The membrane lung with a surface area of 0.8m2 allowed a maximum normalized CO2 elimination rate of 101 ± 12 mL/min with increasing influence of sweep gas flow. The delta of normalized CO2 elimination increased from 4 ± 2 to 26 ± 7 mL/min with blood flow rates being increased from 300 to 1800 mL/min, respectively. CONCLUSIONS: The influence of sweep gas flow on the CO2 removal capacity of ECCO2R systems depends predominantly on blood flow rate and membrane lung surface area. In this model, considerable CO2 removal occurred only with the larger membrane lung surface of 0.8m2 and when blood flow rates of ≥ 900 mL/min were used.

Impact of membrane lung surface area and blood flow on extracorporeal CO2 removal during severe respiratory acidosis.

BACKGROUND: Veno-venous extracorporeal CO2 removal (vv-ECCO2R) is increasingly being used in the setting of acute respiratory failure. Blood flow rates through the device range from 200 ml/min to more than 1500 ml/min, and the membrane surface areas range from 0.35 to 1.3 m2. The present study in an animal model with similar CO2 production as an adult patient was aimed at determining the optimal membrane lung surface area and technical requirements for successful vv-ECCO2R. METHODS: Four different membrane lungs, with varying lung surface areas of 0.4, 0.8, 1.0, and 1.3m2 were used to perform vv-ECCO2R in seven anesthetized, mechanically ventilated, pigs with experimentally induced severe respiratory acidosis (pH 7.0-7.1) using a 20Fr double-lumen catheter with a sweep gas flow rate of 8 L/min. During each experiment, the blood flow was increased stepwise from 250 to 1000 ml/min. RESULTS: Amelioration of severe respiratory acidosis was only feasible when blood flow rates from 750 to 1000 ml/min were used with a membrane lung surface area of at least 0.8 m2. Maximal CO2 elimination was 150.8 ml/min, with pH increasing from 7.01 to 7.30 (blood flow 1000 ml/min; membrane lung 1.3 m2). The membrane lung with a surface of 0.4 m2 allowed a maximum CO2 elimination rate of 71.7 mL/min, which did not result in the normalization of pH, even with a blood flow rate of 1000 ml/min. Also of note, an increase of the surface area above 1.0 m2 did not result in substantially higher CO2 elimination rates. The pressure drop across the oxygenator was considerably lower (<10 mmHg) in the largest membrane lung, whereas the smallest revealed a pressure drop of more than 50 mmHg with 1000 ml blood flow/min. CONCLUSIONS: In this porcine model, vv-ECCO2R was most effective when using blood flow rates ranging between 750 and 1000 ml/min, with a membrane lung surface of at least 0.8 m2. In contrast, low blood flow rates (250-500 ml/min) were not sufficient to completely correct severe respiratory acidosis, irrespective of the surface area of the membrane lung being used. The converse was also true, low surface membrane lungs (0.4 m2) were not capable of completely correcting severe respiratory acidosis across the range of blood flows used in this study.

Fatal HBoV-1 infection in adult female cystic fibrosis patient.

A clinical case of fatal HBoV infection in an adult cystic-fibrosis patient awaiting lung transplantation is reported. The case is important as the genetic background of the underlying disease is congruent with the background of the sole permissive permanent cell culture CuFi-8 which originates also from a CF patient donor.

Extracorporeal membrane oxygenation: evolving epidemiology and mortality.

PURPOSE: The evolution of the epidemiology and mortality of extracorporeal membrane oxygenation (ECMO) remains unclear. The present study investigates the evolving epidemiology and mortality of various ECMO techniques in Germany over time, used for both severe respiratory and cardiac failure. METHODS: Data on all patients receiving venovenous (vv-ECMO) and venoarterial (va-ECMO) ECMO as well as pumpless extracorporeal lung assist/interventional lung assist (PECLA/ILA) outside the operating room in Germany from 1 January 2007 through 31 December 2014 were obtained from the Federal Statistical Office of Germany and analyzed. RESULTS: The incidence of vv-ECMO and va-ECMO in the population increased threefold from 1.0:100,000 inhabitants/year in 2007 to a maximum of 3.0:100,000 in 2012, and from 0.1:100,000 in 2007 to 0.7:100,000 in 2012 and to a maximum of 3.5:100,000 in 2014, respectively. The incidence of arteriovenous PECLA/ILA also increased from 0.4:100,000 to a maximum of 0.6:100,000 in 2011, but decreased thereafter to 0.3:100,000 in 2014. The relative proportion of older patients receiving ECMO is steadily increasing. In-hospital mortality decreased over time and reached 58 and 66 % for vv-ECMO and va-ECMO in 2014, respectively. In addition, mortality steadily increased with age and was especially high in the first 48 h of ECMO use. CONCLUSIONS: In a high-income country like Germany, the use of ECMO has been rapidly increasing since 2007 for both respiratory and cardiac support, with a recent plateau in vv-ECMO use. In-hospital mortality decreased with increasing ECMO utilization, but remains high, especially in older patients and in the first 48 h of use.