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O-49 Neurologic complications after endovascular treatment of thoracic aortic pathology: results from a large Italian single centre registry
FREE ORAL SESSIONS
S21
Introduction. Anaesthesia, thoracotomy, surgical manipulations and cardiopulmonary bypass (CPB) can all produce transient deleterious changes in pulmonary function. These effects can be manifested more profoundly in patients with pre-existing respiratory pathologies. Delayed sternal closure (DSC), when required, is a safe and simple method after CPB for treating haemodynamic instability, bleeding and arrhythmias. Our goal was to compare respiratory system mechanics and function between closed and open chest conditions. Method. In this prospective, consecutive study, the low-frequency (0.5-21 Hz) input impedance of the respiratory (Zrs) and pulmonary systems (ZL) were measured in anaesthetized, mechanically ventilated patients (n⫽159) undergoing elective coronary heart or valvular surgery. Impedance data were recorded before and 10 min after chest opening by sternotomy. The airway resistance (Raw), tissue damping (G) and elastance (H) were obtained from the Zrs or ZL spectra by model fitting. Side stream capnography was also performed and the slope of the third phase (␣III) was analysed. The changes in the compliance (C) and resistance (R) displayed by the ventilator were also recorded before and after sternal opening. Arterial blood gas was measured under both conditions to assess the quotient of the arterial oxygen partial pressure and the fraction of inspired oxygen (Horowitz-coefficient). Results. The open chest condition was associated with significantly lower Raw (8.4⫾0.5[SE] vs. 2.9⫾0.1 cmH2O s/l, P⬍0.001), G (10.1⫾0.6 vs. 6.3⫾0.3 cmH2O/l, P⬍0.001) and H (29.4⫾1.3 vs. 22.0⫾0.9 cm H2O/l, P⬍0.001). Significant decreases in ␣III were also observed after chest opening (1.7⫾0.1 vs. 0.77⫾0.07 mmHg/s, P⬍0.001). Horowitz-coefficient, C and R exhibited significant improvement under the open chest condition (308⫾9 vs. 347⫾9 mmHg, P⬍0.05; 50⫾18 vs. 57⫾19 ml/ cmH2O, P⬍0.001; 10.1⫾3.8 vs. 8.5⫾3.0, P⬍0.001, respectively). Discussion. These results demonstrate that the open chest condition itself provides better respiratory mechanics, improved gas exchange, diminished ventilation inhomogeneity and decreased intrapulmonary shunt than those observed in the intact chest. Taking into account other additional circulatory beneficial effects of DSC, such as decreased right ventricular afterload, increased systemic venous return, and the avoidance of heart compression, DSC may be proposed in patients with severely impaired pulmonary function. Nevertheless, extrapolation of these data to patients with severe acute heart failure and lung oedema requires further investigations in the post-bypass period. O-49 Neurologic complications after endovascular treatment of thoracic aortic pathology: results from a large Italian single centre registry
Michele Clemente1, Sara Spada1, Fabio Caramelli1, Erika Dal Checco1, Guido Frascaroli1, Maria Letizia Bacchi Reggiani2 1
Cardiothoracic Anaesthesia and Intensive Care Unit, 2Institute of Cardiology, Sant’Orsola-Malpighi University, Bologna, Italy Introduction. Endovascular repair of the thoracic aorta (TEVAR) is becoming the treatment of choice for many vascular aortic diseases. The scope of this study was to evaluate the incidence and related risk factors of severe neurological complications (NC) in our clinical experience. Method. A retrospective analysis was performed on 346 patients (pts) who underwent TEVAR surgery at our institution from November 1998 to April 2010. Study end points included evidence of severe NC, defined as stroke, paraplegia, monoplegia, transient mono/paraparesis and complications of cerebrospinal fluid drainage (CSFD). Univariate analysis and multivariate regression models were used to discovered the associated risk factors. Results. The average age was 59 (⫾16) years with 81.5% males. A degenerative aneurysm was present in 68 pts, aortic dissection in 146, traumatic rupture in 70, penetrating ulcer in 29, false aneurysm in 15 and unspecified disorder in 18. 1.54⫾0.73 stents were used per patient with an average length of 201.3⫾90.5 mm. The in-hospital mortality was 2.9%. The total procedures performed on 346 pts were 407. 298 pts underwent only one procedure, 41 needed a second operation and 7 pts needed a third. The NC were 12 in 11 pts: 3 strokes, 4 paraplegia, 2 monoplegia, 3 transient mono/paraparesis. A logistic regression analysis was performed using 31 preoperative and intraoperative variables among which only left subclavian artery covering without revascularization (LSAC) was statistically linked to NC (P⫽0.006; OR 7.089; CI 1.738-28.906). The length of aortic covering didn’t reach statistical significance, although it was very close to it. For this reason we have included it and LSAC in a multivariate regression model. Only the LSAC is independently correlated to NC (P⫽0.018; OR 5.669; CI 1.34123.964). The CSFD was placed in 29 pts, one of whom experienced paraplegia due to an epidural haematoma. Discussion. In our experience the incidence of severe NC after TEVAR is lower than previously reported. Even if the paucity of adverse events limits the power of our statistical analysis, we confirmed the LSAC as a risk factor of neurological sequelae. The incidence of paraplegia in the pts with prophylactic use of CSFD is 3.45%, whereas it is 1.89% in the remaining population. This difference doesn’t reach statistical significance, but it cannot be underestimated. For this reason we reserved the use of CSFD only for the high risk pts.
Oral Session VIII – Thoracic Anaesthesia cen, Debrecen, Hungary, 3University of Ghent, Department of Anaesthesiology, Ghent, Belgium
O-50 Effects of high and low tidal volumes on oxygenation during one-lung ventilation: is less more? 1
1
Tamás Végh , Marianna Juhász , Szilárd Attila Enyedi2, László L. Szegedi3, Béla Fülesdi1 1
1
Szatmári ,
Department of Anaesthesiology and Intensive Care, Debrecen, Hungary, 2Department of Thoracic Surgery, University of Debre-
Introduction. The ideal tidal volume (TV) during one-lung ventilation (OLV) remains controversial [1]. The aim of this work was a crossover-design comparison of the influences of low vs. high TV on systemic and cerebral oxygenation. Method. Sixty patients scheduled for thoracic surgery were randomized into two groups: Group 10/5 (n⫽30) and Group 5/10
S21
Introduction. Anaesthesia, thoracotomy, surgical manipulations and cardiopulmonary bypass (CPB) can all produce transient deleterious changes in pulmonary function. These effects can be manifested more profoundly in patients with pre-existing respiratory pathologies. Delayed sternal closure (DSC), when required, is a safe and simple method after CPB for treating haemodynamic instability, bleeding and arrhythmias. Our goal was to compare respiratory system mechanics and function between closed and open chest conditions. Method. In this prospective, consecutive study, the low-frequency (0.5-21 Hz) input impedance of the respiratory (Zrs) and pulmonary systems (ZL) were measured in anaesthetized, mechanically ventilated patients (n⫽159) undergoing elective coronary heart or valvular surgery. Impedance data were recorded before and 10 min after chest opening by sternotomy. The airway resistance (Raw), tissue damping (G) and elastance (H) were obtained from the Zrs or ZL spectra by model fitting. Side stream capnography was also performed and the slope of the third phase (␣III) was analysed. The changes in the compliance (C) and resistance (R) displayed by the ventilator were also recorded before and after sternal opening. Arterial blood gas was measured under both conditions to assess the quotient of the arterial oxygen partial pressure and the fraction of inspired oxygen (Horowitz-coefficient). Results. The open chest condition was associated with significantly lower Raw (8.4⫾0.5[SE] vs. 2.9⫾0.1 cmH2O s/l, P⬍0.001), G (10.1⫾0.6 vs. 6.3⫾0.3 cmH2O/l, P⬍0.001) and H (29.4⫾1.3 vs. 22.0⫾0.9 cm H2O/l, P⬍0.001). Significant decreases in ␣III were also observed after chest opening (1.7⫾0.1 vs. 0.77⫾0.07 mmHg/s, P⬍0.001). Horowitz-coefficient, C and R exhibited significant improvement under the open chest condition (308⫾9 vs. 347⫾9 mmHg, P⬍0.05; 50⫾18 vs. 57⫾19 ml/ cmH2O, P⬍0.001; 10.1⫾3.8 vs. 8.5⫾3.0, P⬍0.001, respectively). Discussion. These results demonstrate that the open chest condition itself provides better respiratory mechanics, improved gas exchange, diminished ventilation inhomogeneity and decreased intrapulmonary shunt than those observed in the intact chest. Taking into account other additional circulatory beneficial effects of DSC, such as decreased right ventricular afterload, increased systemic venous return, and the avoidance of heart compression, DSC may be proposed in patients with severely impaired pulmonary function. Nevertheless, extrapolation of these data to patients with severe acute heart failure and lung oedema requires further investigations in the post-bypass period. O-49 Neurologic complications after endovascular treatment of thoracic aortic pathology: results from a large Italian single centre registry
Michele Clemente1, Sara Spada1, Fabio Caramelli1, Erika Dal Checco1, Guido Frascaroli1, Maria Letizia Bacchi Reggiani2 1
Cardiothoracic Anaesthesia and Intensive Care Unit, 2Institute of Cardiology, Sant’Orsola-Malpighi University, Bologna, Italy Introduction. Endovascular repair of the thoracic aorta (TEVAR) is becoming the treatment of choice for many vascular aortic diseases. The scope of this study was to evaluate the incidence and related risk factors of severe neurological complications (NC) in our clinical experience. Method. A retrospective analysis was performed on 346 patients (pts) who underwent TEVAR surgery at our institution from November 1998 to April 2010. Study end points included evidence of severe NC, defined as stroke, paraplegia, monoplegia, transient mono/paraparesis and complications of cerebrospinal fluid drainage (CSFD). Univariate analysis and multivariate regression models were used to discovered the associated risk factors. Results. The average age was 59 (⫾16) years with 81.5% males. A degenerative aneurysm was present in 68 pts, aortic dissection in 146, traumatic rupture in 70, penetrating ulcer in 29, false aneurysm in 15 and unspecified disorder in 18. 1.54⫾0.73 stents were used per patient with an average length of 201.3⫾90.5 mm. The in-hospital mortality was 2.9%. The total procedures performed on 346 pts were 407. 298 pts underwent only one procedure, 41 needed a second operation and 7 pts needed a third. The NC were 12 in 11 pts: 3 strokes, 4 paraplegia, 2 monoplegia, 3 transient mono/paraparesis. A logistic regression analysis was performed using 31 preoperative and intraoperative variables among which only left subclavian artery covering without revascularization (LSAC) was statistically linked to NC (P⫽0.006; OR 7.089; CI 1.738-28.906). The length of aortic covering didn’t reach statistical significance, although it was very close to it. For this reason we have included it and LSAC in a multivariate regression model. Only the LSAC is independently correlated to NC (P⫽0.018; OR 5.669; CI 1.34123.964). The CSFD was placed in 29 pts, one of whom experienced paraplegia due to an epidural haematoma. Discussion. In our experience the incidence of severe NC after TEVAR is lower than previously reported. Even if the paucity of adverse events limits the power of our statistical analysis, we confirmed the LSAC as a risk factor of neurological sequelae. The incidence of paraplegia in the pts with prophylactic use of CSFD is 3.45%, whereas it is 1.89% in the remaining population. This difference doesn’t reach statistical significance, but it cannot be underestimated. For this reason we reserved the use of CSFD only for the high risk pts.
Oral Session VIII – Thoracic Anaesthesia cen, Debrecen, Hungary, 3University of Ghent, Department of Anaesthesiology, Ghent, Belgium
O-50 Effects of high and low tidal volumes on oxygenation during one-lung ventilation: is less more? 1
1
Tamás Végh , Marianna Juhász , Szilárd Attila Enyedi2, László L. Szegedi3, Béla Fülesdi1 1
1
Szatmári ,
Department of Anaesthesiology and Intensive Care, Debrecen, Hungary, 2Department of Thoracic Surgery, University of Debre-
Introduction. The ideal tidal volume (TV) during one-lung ventilation (OLV) remains controversial [1]. The aim of this work was a crossover-design comparison of the influences of low vs. high TV on systemic and cerebral oxygenation. Method. Sixty patients scheduled for thoracic surgery were randomized into two groups: Group 10/5 (n⫽30) and Group 5/10