Understanding Ventilation Strategies for ECMO Patients at a Community Hospital

Understanding Ventilation Strategies for ECMO Patients at a Community Hospital Kenneth Miller, Matthew McCambridge MD, Neophytos Zambas Background: Extracorporeal Membrane Oxygenation (commonly abbreviated to ECMO) is a modified form of cardiopulmonary bypass utilized in patients with severe yet reversible respiratory and/or cardiac failure (1). The extracorporeal circuit is used to directly oxygenate and remove carbon dioxide from the patient’s blood (2). This type of therapy is used as temporary support for heart and lung function leading to organ recovery or replacement. By maintaining adequate gas exchange and circulating the patients’ blood, the medical intensivist is able to keep the patient alive while the cardiopulmonary system recovers. Blood is withdrawn from the patient’s venous system into an extracorporeal circuit by a mechanical pump before entering an oxygenator. Within the oxygenator, blood passes along one side of a membrane, which provides a blood–gas interface for diffusion of gases. The oxygenated extracorporeal blood may then be warmed or cooled as needed and is returned to a central vein. This specific technique is termed “venovenous” ECMO, because blood is both withdrawn from and returned to the venous system (2). In venoarterial ECMO (VA ECMO) a similar concept is utilized, except the blood is withdrawn from the venous system (femoral vein) and returned into the arterial system (aorta). ECMO has been shown to positively influence patient’s outcomes with compromised cardiopulmonary systems. The most common reasons patients are placed on ECMO are lung compromising and include diseases such as Acute Respiratory Distress Syndrome (ARDS), Pneumonia, Sepsis, and many others. In order to maintain the patient’s lung mechanics and inflation during extracorporeal membrane oxygenation it is necessary to incorporate one of the various forms of mechanical ventilation strategies. Airway Pressure Release Ventilation (APRV), Pressure Control Mandatory Ventilation (PCMV), Pressure Support Ventilation (PSV) for the spontaneously breathing patient, and High Frequency Percussive Ventilation (HFPV) are all ventilatory strategies that can be used in conjunction with ECMO to help maintain the patients lung function, the most common being pressure control mandatory ventilation (PCMV). HFPV is a nonconventional form of ventilation which is utilized when PCMV and ECMO parameters are maximized and gas exchange remains inadequate, the patient has maintained secretions after frequent bronchoscopies, and the patients lung hypo inflation is marked be a compliance of less than or equal to 12cm H2O. HFPV has been shown to work as both an effective ventilator and a powerful mucokinetic. By keeping the patients lungs operational during ECMO management, the patient is more quickly weaned off of ECMO due to maintained lung compliance, elasticity, and ventilation. To further understand the effectiveness and uses of HFPV employed by the VDR ventilator, the data of 40 patients who were placed on ECMO in combination with either high frequency percussive ventilation or pressure control mandatory ventilation was analyzed. Methods: 42 patients were cannulated with ECMO at Lehigh Valley Health Network (LVHN) since January of 2013. All patients’ data was analyzed and a comprehensive ECMO database was created. All of these patients were also placed on mechanical ventilation during their treatment with ECMO. 21 of these 42 patients were treated with high frequency percussive ventilation (HFPV) and various aspects of their data were analyzed to better understand the efficacy of the VDR ventilator. Patient age, etiology, reason for use of HFPV ventilation strategy, RESP score (pulmonary score developed by The Australian and New Zealand Intensive Care Research Centre), and current status of patient were all taken into consideration. By comparing these various pieces of data the effectiveness of the HFPV strategy was determined. Results: The average survival rate recorded in the ELSO database (Extracorporeal Life Support Organization) is 57%. Since the initiation of the ECMO program at the Lehigh Valley Health Network (LVHN) 42 patients have undergone ECMO management and 28 of the 42 patients survived (68.3% survival). One of the patients is currently undergoing ECMO management and therefore this patient’s status was not factored into the survival rate. Of the various ventilation strategies used in combination with ECMO management, HFPV administered by VDR was used on 21 patients at some point during their management, prior to cannulation, during ECMO management, or both. Of the 21 total HFPV administered by VDR patients, 20 of them have been decannulated (taken off of ECMO) and 14 of them survived, giving these patients a survival rate of 70%. The average age of these HFPV administered by VDR patients was recorded at 48.04 years and included 11 female patients and 10 male patients. The most common etiologies of these HFPV administered by VDR ECMO patients included H1N1 (7), Pneumonia (4), and Aspiration (6). Patient ID Numbers Etiology Primary Reason For Being Put On VDR Age Of Patient Total Respiratory Score Status 1884990 H1N1/ARDS Gas Exchange 47 1 alive 1135678 Staph Pneumonia Gas Exchange 32 -3 expired 1952461 H1N1 Gas Exchange 51 4 alive 1416314 Aspiration Gas Exchange 31 4 alive Pre-ECMO VDR Patients: Table 1 Of the 4 ECMO patients who were placed on a VDR prior to ECMO cannulation, 3 of them survived giving a survival rate of 75%. The average age of these 4 patients was found to be 40.25 years. Conclusions should not be drawn from these samples due to the low patient population. It can be concluded however, that HFPV administered by VDR is an appropriate ventilatory strategy than can have positive results. During ECMO VDR Patients: Table 2 Patient ID Number Etiology Primary Reason For Being Put On VDR Age Of Patient Total Respiratory Score Status 792610 Pulmonary Embolism Secretions (Used As Mucokinetic) 46 4 alive 1823618 Aspiration Secretions (Used As Mucokinetic) 51 4 alive 1920871 H1N1 Air Leak/Pneumonia 25 4 alive 1786205 MRSA Pneumonia Secretions (Used As Mucokinetic) 59 4 alive 1951444 Unknown Secretions (Used As Mucokinetic) 39 1 alive 1955049 H1N1 Secretions (Used As Mucokinetic) 44 7 alive 1954753 H1N1 Secretions (Used As Mucokinetic) 47 4 alive 1955399 H1N1 Gas Exchange 62 1 expired 58012 Pneumonia Secretions (Used As Mucokinetic) 66 -1 withdrawal 363686 Aspiration Secretions (Used As Mucokinetic) 32 5 alive 948061 Pneumonia Secretions (Used As Mucokinetic) 45 1 expired 473436 Pneumothorax Lung Recruitment 33 -4 N/A 1544181 Aspiration Pneumonitis Secretions (Used As Mucokinetic) 53 2 alive Of the 13 ECMO patients who were placed on a VDR while undergoing ECMO management, 9 of them survived giving us a survival rate of 75% (one of the patients is currently undergoing ECMO management so their status is not included in the survival rate). The average age of these 13 patients was found to be 46.3 years. Conclusions should not be drawn from this data due to the small sample size. It is clear however that HFPV is a viable ventilatory strategy. Prior to and During ECMO VDR Patients: Table 3 Patient ID Number Etiology Age Of Patient Total Respiratory Score Status 1213954 DKA, Aspirated, Pulmonary Embolism 28 3 alive 1949522 H1N1 61 -1 alive 1259060 Aspiration Pneumonitis 74 1 expired 264715 Aspiration 83 3 expired Of the 4 ECMO patients who were placed on a VDR prior to ECMO cannulation as well as while undergoing ECMO management, 2 survived giving us a survival rate of 50%. The average age of these patients was 61.5 years. Conclusions should not be drawn from this data due to the small sample size. All ECMO VDR Patients: Table 4 Number Of Patients Average Age Average Respiratory Score Survival Rate Pre-ECMO 4 40.25 1.5 75% During ECMO 13 46.3 2.23 75% Both Pre & During 4 61.5 1.5 50% Of the 21 ECMO patients with whom HFPV administered by VDR was utilized, 4 were placed on a VDR prior to ECMO cannulation, 13 were placed on a VDR while undergoing ECMO management, and 4 were placed on a VDR prior to ECMO cannulation and during ECMO management. These 3 sets of patients had survival rates of 75%, 75%, and 50% respectively. Conclusions should not be drawn from this data due to the small sample size. It is clear that HFPV administered by a VDR is a viable and successful ventilatory strategy. VDR ECMO Patients vs. PCMV ECMO Patients: Table 5 Number Of Patients Average Age Average Respiratory Score Survival Rate VDR 21 48.04 1.95 70% No VDR 21 53.26 1.48 66.7% When comparing the VDR and non VDR ECMO patient survival rates at LVHN (70% and 66.7% respectively), with the national average recorded in the ELSO database (57%), it is evident that both strategies produce positive results. Due to the new nature of the ECMO program at LVHN, the sample size is relatively small and therefore concrete conclusions cannot be drawn. Discussion: Since January of 2013 Lehigh Valley Health network has utilized ECMO management on a total of 42 patients with Acute Respiratory Distress Syndrome (ARDS). Lehigh Valley Health network has maintained a survival rate of over 68.3%, which markedly higher than the national average recorded by the ELSO database of 57%. By utilizing various ventilatory strategies (VDR), patients who were not being oxygenated properly using PCMV or were otherwise unstable were more successfully managed. By studying the success rate of High Frequency Percussive Ventilation and the VDR ventilator we hoped to show that not only is this mode of ventilation capable of maintaining lung mechanics during ECMO management, but that it could have improved patient outcomes for patients with whom PCMV is not sufficient. Of the 42 ECMO patients, HFPV with VDR was utilized on a total of 21 patients. These patients were ventilated using HFPV with VDR for various reasons including gas exchange, air leaks, lung recruitment, and sustained secretions. The ECMO patients with whom HFPV was utilized ended up with a survival rate of over 70%. The patients who were ventilated using conventional ventilation (PCMV) had a slightly lower survival rate of 66.7% resulting with an overall survival rate of 68.3%. Looking at this data it is clear that HFPV is not only a legitimate ventilation strategy, but can have extremely positive outcomes on patients who were not responding well to conventional ventilation or were put on HFPV due to other factors (see tables 1-3). We believe that among other factors, LVHN’s utilization of HFPV and the VDR ventilator contribute greatly to the much higher than average survival rates of our ECMO patients. References: Mannino, F., Anas, N., & Cleary, M. (n.d.). Extracorporeal Membrane Oxygenation (ECMO) for the. . Retrieved July 15, 2014, from http://www.calthoracic.org/sites/default/files/ecmopp.pdf Columbia University College of Physicians and Surgeons. (2011). Extracorporeal Membrane Oxygenation for ARDS in adults. The New England Journal of Medicine, 365, 1905-1914

The Socio-Political Debate of Dying Today in the United Kingdom and New Zealand: ‘Letting Go’ of the Biomedical Model of Care in Order to Develop a Contemporary Ars Moriendi

Death is a reality of life. Despite this inevitability, death today remains unwelcome and has been sequestered into the enclaves of medical practice as a means of quelling the rising tide of fear it provokes. Medical practice currently maintains power over the dying individual, actualised through the selective collaboration between medicine and law as a means of subverting the individual who attempts to disrupt the contemporary accepted norms of dying. There is, however, a shift on the horizon as to whether we can make the notion of a true choice become a reality in New Zealand. This serves to offer a compelling movement towards individuals seeking control of their dying trajectory to actualise the notion of individual choice. With this shifting landscape there is an opportunity to be grasped to change how we manage our dying trajectory away from the biomedical patterns of behaviour when dying, in order to balance life decisions. To achieve this prospect, we need to engage with a framework upon which to pin the changes. This paper offers a re-framing and re-presenting approach, using illustrative examples that draw upon British and New Zealand literature, together with over 50 years of professional nursing, and the Ars Moriendi to reflect upon the self-centricity of the contemporary Western individual to access a ‘good death’ of choice

The Walls of Eupalinos Aqueduct, Samos Island, Greece. Description, Pathology and Proposed Restoration Measures

Το Ευπαλίνειο Υδραγωγείο κατασκευάστηκε στα μέσα του 6 ου π.Χ. αιώνα στην Σάμο στο αρχιπέλαγο το Βορείου Αιγαίου. Ο Ηρόδοτος (481-425 π.Χ.) είναι ο πρώτος ιστορικός που αναφέρεται στο μνημείο. Αναφέρει τον Ευπαλίνο, γιο του Ναυστρόφου από τα Μέγαρα ως τον υπεύθυνο μηχανικό για την μελέτη και την κατασκευή του μνημείου. Επίσης περιγράφει και την μέθοδο κατασκευής που το κάνει μοναδικό: «...κατάφεραν να διανοίξουνε μία σήραγγα από δύο στόμια (αρξάμενον, αμφίστομον), στην βάση ενός βουνού ύψους 150 μέτρων». Η Εγνατία Οδός Α.Ε. σε συνεργασία με την Νομαρχία της Σάμου και το Υπουργείο Πολιτισμού ξεκίνησαν την εκπόνηση μίας πολυθεματικής μελέτης με σκοπό την προστασία και την αποκατάσταση του μνημείου. Η μελέτη συμπεριλάμβανε τοπογραφικές εργασίες, γεωλογικές και γεωφυσικές έρευνες όπως και στατικές, γεωτεχνικές και αρχιτεκτονικές εργασίες. Το βασικό τμήμα του υδραγωγείου είναι η σήραγγα μήκους 1036 μ που περιγράφεται από τον Ηρόδοτο. Για μήκος 165 μ η σήραγγα είναι επενδυμένη από λιθοδομή, εξαιρετικής ποιότητας κατασκευής, που χρονολογείται στην Αρχαϊκή εποχή. Επίσης, για μήκος 63 μ είναι επενδυμένη από λιθοδομή κατασκευασμένη από πλίνθους συγκολλημένους με κονίαμα. Αυτή η λιθοδομή χρονολογείται στην Ρωμαϊκή εποχή. Αυτές οι επενδύσεις σε κάποιες θέσεις έχουν παραμορφωθεί εξαιτίας γεωστατικών πιέσεων και μερικώς έχουν αστοχήσει. Στα πλαίσια των μελετών αποκατάστασής τους έγιναν διερευνήσεις με GPR (Ground Penetration Radar) και ηλεκτρικές διασκοπήσεις ERT (Εlectrical Resistivity Tomograph). Με τις μεθόδους αυτές διερευνήθηκε το πάχος της επένδυσης και σε κάποιο βαθμό και το πλάτος της εκσκαφής από πίσω τους. Ο χώρος μεταξύ της Αρχαϊκής επένδυσης και της περιμέτρου της εκσκαφής είναι πληρωμένος με καλά στοιβαγμένους λίθους μερικώς επεξεργασμένους. Η μέθοδος GPR φαίνεται να εκτιμά με καλή ακρίβεια το πάχος των δομικών λίθων που συνιστούν τις παρειές της επένδυσης (20 εκ. έως 40 εκ). Η μέθοδος ERT φαίνεται να εκτιμά με καλή ακρίβεια την θέση της περιμέτρου της υπόγειας εκσκαφής ή αλλιώς την διεπιφάνεια της εκσκαφής με το υλικό πλήρωσης. Το πάχος της πλήρωσης συν αυτό της επένδυσης βρέθηκε να κυμαίνεται από 60 εκ έως 200 εκ.Κατά πάσα πιθανότητα αυτό σημαίνει πως στα προστατευμένα τμήματα της σήραγγας επισυνέβησαν σημαντικές και συστηματικές καταρρεύσεις του εδάφους. Και αυτό γιατί οι προκύπτουσες διαστάσεις της υπόγειας εκσκαφής στις περιοχές αυτές, προκύπτουν σημαντικά μεγαλύτερες από τις αντίστοιχες στα μη προστατευμένα τμήματα της σήραγγας. Αυτή η παρατήρηση σε συνδυασμό με την μεγάλη υδροφορία και τα διαπιστωμένα μαλακά εδάφη στα ίδια τμήματα, θα μπορούσε να εξηγήσει την απόφαση του Ευπαλίνου να προστατεύσει την περίμετρο της υπόγειας εκσκαφής με λιθοδομή. Επιπρόσθετα άλλες γεωφυσικές και γεωλογικές έρευνες εντόπισαν ζώνες ρηγμάτων που τέμνουν την σήραγγα στις προαναφερθείσες θέσεις, εκεί δηλαδή που πιθανολογούνται εδαφικές αστοχίες. Μία απλοποιημένη ανάλυση με την μέθοδο των πεπερασμένων στοιχείων ερμηνεύει τις παρατηρούμενες παραμορφώσεις της επένδυσης υποθέτοντας την ύπαρξη μαλακού εδάφους στην περίμετρο της σήραγγας.Τα μέτρα προστασίας/αποκατάστασης που διαστασιολογήθηκαν για την Αρχαϊκή επένδυση περιλαμβάνουν: α) αποσυναρμολόγηση της οροφής λίθο προς λίθο και μερικώς, των παρειών της επένδυσης, β) υποστήριξη του εδάφους με ανοξείδωτα αγκύρια, πλαίσια και μανδύα από σκυρόδεμα, και γ) ανακατασκευή της επένδυσης στην αρχική της γεωμετρία, δηλαδή στην γεωμετρία που είχε πριν παραμορφωθεί. Τα μέτρα αυτά (τα μεταλλικά πλαίσια, τα αγκύρια και μανδύας του σκυροδέματος) θα παραλάβουν το σύνολο των γεωστατικών φορτίων έτσι ώστε η επένδυση να είναι στην τελική της κατάσταση αφόρτιστη. Όσον αφορά στην Ρωμαϊκή επένδυση, λόγω των διαφορετικών καταστάσεων φόρτισής της και του τύπου αστοχίας του εδάφους εκεί, τα μέτρα αποκατάστασης περιλαμβάνουν την απομάκρυνση του αστοχήσαντος εδάφους πάνω από τον θόλο της πρώτης, την αποσόβηση νέων καταπτώσεων και την ενίσχυση της λιθοδομής με αδρανή ενέματα.The Aqueduct of Eupalinos was built in the mid-sixth century B.C, on the island of Samos that lies in the archipelago of the north Aegean Sea. Herodotus (481-425 B.C.) was the first historian to refer to the monument. He names Eupalinos, son of Naustrophus, born in the city of Megara as the engineer responsible for the design and construction of this ancient project. He also describes the method of construction that makes this monument unique: “…One is a tunnel, under a hill one hundred and fifty fathoms high, carried entirely through the base of the hill; its excavation started from two portals (αρξάμενον, αμφίστομον) …”. Egnatia Odos S.A2. in cooperation with the Prefecture of Samos and the Ministry of Culture initiated a multi-discipline design study to protect and restore the monument. The designs included surveying works, geological and geophysical investigations, as well as geotechnical, structural and architectural works. The main component of the aqueduct is the 1036 m long tunnel described by Herodotus. For a length of 165 m the tunnel is protected by dry masonry walls and vaults of remarkable quality, built in the Archaic era. For a length of 63 m it is protected by mortared masonry walls and vaults, built in the Roman-era. These walls at some locations have suffered significant deformation, due to ground pressures, and have partially failed. In order to restore the damaged sections of the wall, its structure was investigated with the use of ground penetrating radar (GPR) and Εlectrical Resistivity Tomography (ERT). These methods indicated the thickness of the wall and to some extent the width of the excavation behind it. The space between the dry masonry of the Archaic wall and the excavation perimeter is backfilled with well stacked partially hewn stones. GPR seems to accurately determine the thickness of the massive building stones (20 to 40 cm thick) that form the wall’s sides. ET seems to accurately determine the interface between the excavation perimeter and the backfill. The thickness of the backfill and the wall was found to range from 60 cm to 200 cm. This most likely suggests that at the protected sections the tunnel excavation suffered significant and systematic ground collapses. This is because the derived tunnel excavation dimensions at that point are much larger than the ones of the unprotected tunnel.  The latter combined with the high ground water inflows now present, in the area and the identified poor ground conditions, could justify the decision of Eupalinos to protect the tunnel’s excavation perimeter with the dry masonry walls. Other geophysical and geological investigations identified significant fault zones that cross the tunnel at the previously mentioned locations, where the assumed ground collapses were observed. A simplified deformation analysis that was carried out using finite element modelling shows that the deformation and the observed wall failures can be roughly explained by assuming poor ground conditions around the tunnel. The protection/restoration measures that were dimensioned for the Archaic type wall include: a) a staged, stone by stone, dismantling of the vaults and partially of the wall, b) supporting the ground behind them with stainless steel rock bolts, steel sets and a concrete mantle, and c) rebuilding the whole at its original “pre-deformed” position. These measures (steel sets, concrete mantle and rock bolts) aim in undertaking the full ground load so that the wall, when rebuilt, will be practically unloaded. Due to the different loading conditions and ground failure mode, the restoration measures designed for the Roman-era wall, aim to remove the rock (load) that fell on the roof arch, to prevent further rock falls and to strengthen the mortared masonry with neutral grouts

The Walls of Eupalinos Aqueduct, Samos Island, Greece. Description, Pathology and Proposed Restoration Measures

Το Ευπαλίνειο Υδραγωγείο κατασκευάστηκε στα μέσα του 6 ου π.Χ. αιώνα στην Σάμο στο αρχιπέλαγο το Βορείου Αιγαίου. Ο Ηρόδοτος (481-425 π.Χ.) είναι ο πρώτος ιστορικός που αναφέρεται στο μνημείο. Αναφέρει τον Ευπαλίνο, γιο του Ναυστρόφου από τα Μέγαρα ως τον υπεύθυνο μηχανικό για την μελέτη και την κατασκευή του μνημείου. Επίσης περιγράφει και την μέθοδο κατασκευής που το κάνει μοναδικό: «...κατάφεραν να διανοίξουνε μία σήραγγα από δύο στόμια (αρξάμενον, αμφίστομον), στην βάση ενός βουνού ύψους 150 μέτρων». Η Εγνατία Οδός Α.Ε. σε συνεργασία με την Νομαρχία της Σάμου και το Υπουργείο Πολιτισμού ξεκίνησαν την εκπόνηση μίας πολυθεματικής μελέτης με σκοπό την προστασία και την αποκατάσταση του μνημείου. Η μελέτη συμπεριλάμβανε τοπογραφικές εργασίες, γεωλογικές και γεωφυσικές έρευνες όπως και στατικές, γεωτεχνικές και αρχιτεκτονικές εργασίες. Το βασικό τμήμα του υδραγωγείου είναι η σήραγγα μήκους 1036 μ που περιγράφεται από τον Ηρόδοτο. Για μήκος 165 μ η σήραγγα είναι επενδυμένη από λιθοδομή, εξαιρετικής ποιότητας κατασκευής, που χρονολογείται στην Αρχαϊκή εποχή. Επίσης, για μήκος 63 μ είναι επενδυμένη από λιθοδομή κατασκευασμένη από πλίνθους συγκολλημένους με κονίαμα. Αυτή η λιθοδομή χρονολογείται στην Ρωμαϊκή εποχή. Αυτές οι επενδύσεις σε κάποιες θέσεις έχουν παραμορφωθεί εξαιτίας γεωστατικών πιέσεων και μερικώς έχουν αστοχήσει. Στα πλαίσια των μελετών αποκατάστασής τους έγιναν διερευνήσεις με GPR (Ground Penetration Radar) και ηλεκτρικές διασκοπήσεις ERT (Εlectrical Resistivity Tomograph). Με τις μεθόδους αυτές διερευνήθηκε το πάχος της επένδυσης και σε κάποιο βαθμό και το πλάτος της εκσκαφής από πίσω τους. Ο χώρος μεταξύ της Αρχαϊκής επένδυσης και της περιμέτρου της εκσκαφής είναι πληρωμένος με καλά στοιβαγμένους λίθους μερικώς επεξεργασμένους. Η μέθοδος GPR φαίνεται να εκτιμά με καλή ακρίβεια το πάχος των δομικών λίθων που συνιστούν τις παρειές της επένδυσης (20 εκ. έως 40 εκ). Η μέθοδος ERT φαίνεται να εκτιμά με καλή ακρίβεια την θέση της περιμέτρου της υπόγειας εκσκαφής ή αλλιώς την διεπιφάνεια της εκσκαφής με το υλικό πλήρωσης. Το πάχος της πλήρωσης συν αυτό της επένδυσης βρέθηκε να κυμαίνεται από 60 εκ έως 200 εκ.Κατά πάσα πιθανότητα αυτό σημαίνει πως στα προστατευμένα τμήματα της σήραγγας επισυνέβησαν σημαντικές και συστηματικές καταρρεύσεις του εδάφους. Και αυτό γιατί οι προκύπτουσες διαστάσεις της υπόγειας εκσκαφής στις περιοχές αυτές, προκύπτουν σημαντικά μεγαλύτερες από τις αντίστοιχες στα μη προστατευμένα τμήματα της σήραγγας. Αυτή η παρατήρηση σε συνδυασμό με την μεγάλη υδροφορία και τα διαπιστωμένα μαλακά εδάφη στα ίδια τμήματα, θα μπορούσε να εξηγήσει την απόφαση του Ευπαλίνου να προστατεύσει την περίμετρο της υπόγειας εκσκαφής με λιθοδομή. Επιπρόσθετα άλλες γεωφυσικές και γεωλογικές έρευνες εντόπισαν ζώνες ρηγμάτων που τέμνουν την σήραγγα στις προαναφερθείσες θέσεις, εκεί δηλαδή που πιθανολογούνται εδαφικές αστοχίες. Μία απλοποιημένη ανάλυση με την μέθοδο των πεπερασμένων στοιχείων ερμηνεύει τις παρατηρούμενες παραμορφώσεις της επένδυσης υποθέτοντας την ύπαρξη μαλακού εδάφους στην περίμετρο της σήραγγας.Τα μέτρα προστασίας/αποκατάστασης που διαστασιολογήθηκαν για την Αρχαϊκή επένδυση περιλαμβάνουν: α) αποσυναρμολόγηση της οροφής λίθο προς λίθο και μερικώς, των παρειών της επένδυσης, β) υποστήριξη του εδάφους με ανοξείδωτα αγκύρια, πλαίσια και μανδύα από σκυρόδεμα, και γ) ανακατασκευή της επένδυσης στην αρχική της γεωμετρία, δηλαδή στην γεωμετρία που είχε πριν παραμορφωθεί. Τα μέτρα αυτά (τα μεταλλικά πλαίσια, τα αγκύρια και μανδύας του σκυροδέματος) θα παραλάβουν το σύνολο των γεωστατικών φορτίων έτσι ώστε η επένδυση να είναι στην τελική της κατάσταση αφόρτιστη. Όσον αφορά στην Ρωμαϊκή επένδυση, λόγω των διαφορετικών καταστάσεων φόρτισής της και του τύπου αστοχίας του εδάφους εκεί, τα μέτρα αποκατάστασης περιλαμβάνουν την απομάκρυνση του αστοχήσαντος εδάφους πάνω από τον θόλο της πρώτης, την αποσόβηση νέων καταπτώσεων και την ενίσχυση της λιθοδομής με αδρανή ενέματα.The Aqueduct of Eupalinos was built in the mid-sixth century B.C, on the island of Samos that lies in the archipelago of the north Aegean Sea. Herodotus (481-425 B.C.) was the first historian to refer to the monument. He names Eupalinos, son of Naustrophus, born in the city of Megara as the engineer responsible for the design and construction of this ancient project. He also describes the method of construction that makes this monument unique: “…One is a tunnel, under a hill one hundred and fifty fathoms high, carried entirely through the base of the hill; its excavation started from two portals (αρξάμενον, αμφίστομον) …”. Egnatia Odos S.A2. in cooperation with the Prefecture of Samos and the Ministry of Culture initiated a multi-discipline design study to protect and restore the monument. The designs included surveying works, geological and geophysical investigations, as well as geotechnical, structural and architectural works. The main component of the aqueduct is the 1036 m long tunnel described by Herodotus. For a length of 165 m the tunnel is protected by dry masonry walls and vaults of remarkable quality, built in the Archaic era. For a length of 63 m it is protected by mortared masonry walls and vaults, built in the Roman-era. These walls at some locations have suffered significant deformation, due to ground pressures, and have partially failed. In order to restore the damaged sections of the wall, its structure was investigated with the use of ground penetrating radar (GPR) and Εlectrical Resistivity Tomography (ERT). These methods indicated the thickness of the wall and to some extent the width of the excavation behind it. The space between the dry masonry of the Archaic wall and the excavation perimeter is backfilled with well stacked partially hewn stones. GPR seems to accurately determine the thickness of the massive building stones (20 to 40 cm thick) that form the wall’s sides. ET seems to accurately determine the interface between the excavation perimeter and the backfill. The thickness of the backfill and the wall was found to range from 60 cm to 200 cm. This most likely suggests that at the protected sections the tunnel excavation suffered significant and systematic ground collapses. This is because the derived tunnel excavation dimensions at that point are much larger than the ones of the unprotected tunnel.  The latter combined with the high ground water inflows now present, in the area and the identified poor ground conditions, could justify the decision of Eupalinos to protect the tunnel’s excavation perimeter with the dry masonry walls. Other geophysical and geological investigations identified significant fault zones that cross the tunnel at the previously mentioned locations, where the assumed ground collapses were observed. A simplified deformation analysis that was carried out using finite element modelling shows that the deformation and the observed wall failures can be roughly explained by assuming poor ground conditions around the tunnel. The protection/restoration measures that were dimensioned for the Archaic type wall include: a) a staged, stone by stone, dismantling of the vaults and partially of the wall, b) supporting the ground behind them with stainless steel rock bolts, steel sets and a concrete mantle, and c) rebuilding the whole at its original “pre-deformed” position. These measures (steel sets, concrete mantle and rock bolts) aim in undertaking the full ground load so that the wall, when rebuilt, will be practically unloaded. Due to the different loading conditions and ground failure mode, the restoration measures designed for the Roman-era wall, aim to remove the rock (load) that fell on the roof arch, to prevent further rock falls and to strengthen the mortared masonry with neutral grouts

Analytical approaches and trends in the determination of psychoactive drugs in air

Understanding of the levels of psychoactive drugs in air is important for assessing both occupational and environmental exposure. Intelligence on the usage and manufacture of illegal drugs can also be gained. Environmental analysis and determination of air quality has recently expanded from its traditional focus to new pollutant categories that include illicit and psychoactive drugs. This is attributed to a greater part on the development of new, advanced techniques, such as liquid chromatography/mass spectrometry (LC/MS), allowing for the trace determination of such compounds down to the parts-per-trillion (ng/L) levels generally reported in air. Studies have also investigated the effects of firsthand and secondhand smoking of drugs, such as cocaine, cannabis and opium. Generally, these have shown secondhand smoke effects to be limited, apart from in the case of opium. Some studies have highlighted ill effects resulting through the exposure of vapors and dusts from the storage of drugs, but this has been shown to result from mould and other fungal contaminates. Investigations into the possible occupational exposures resulting from the use of anesthetic drugs in surgery and accident and emergency have focused on nitrous oxide, sevoflurane, methoxyflurane, isoflurane, propofol and fentanyl. This review focuses on developments and applications for the determination of psychoactive drugs in air

A qualitative study of advanced nurse practitioners’ use of physical assessment skills in the community: shifting skills across professional boundaries

Aim To explore multiple perspectives on the use of physical assessment skills by Advanced Nurse Practitioners in the UK Background Physical assessment skills practices are embedded in advanced nursing practice roles in the UK. There is little evidence on how these skills are used by Advanced Nurse Practitioners' on the community. Design Case study Methodology and methods. A qualitative interpretative single-embedded case study of 22 participants from South of England. A framework method analysed interview data collected by the researcher between March and August 2013. Participants included nurses, doctors, nurse educators and managers Findings Physical assessment skills education at Universities are part of a policy shift to develop a flexible workforce in the UK. Shared physical assessment practices are less to do with role substitution and more about preparing practitioners with skills that are fit for purpose. Competence capability and performance with physical assessment skills are an expectation of advanced nursing practice. Conclusions These skills are used successfully by community Advanced Nurse Practitioners to deliver a wide range of services in response to changing patient need. The introduction of physical assessment skills education to undergraduate professional preparation would create a firm foundation to develop these skills in post-graduate education. Relevance to clinical practice. • Physical assessment education prepares nurses with the clinical competencies to carry out healthcare reforms in the UK • Shared sets of clinical assessment competencies between disciplines have better outcomes for patients • Levels of assessment competence can depend on the professional attributes of individual practitioners • Unsupportive learning cultures can hinder professional development of advanced nursing practic

Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)

Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic

Περισσότερο φως στο τούνελ του Ευπαλίνου

The restoration works on the unique tunnel of Eupalinos, part of the Archaic aqueduct on Samos, and the information that the new evidence from them provides, especially on its linings, are presented in brief. New hypotheses for the design and the construction of the tunnel are also proposed. The center line of the tunnel was initially laid out over the hill surface with long scaffolding. Then, in order to ensure the accuracy of the excavation, the line was transposed inside with the help of two light signals, one on the opposite hillside to the north and one on a wooden tower near the seaside to the south. The problem of the loss of the northern signal on account of low visibility caused by the flow of water, which produced high humidity and consequently a misty atmosphere inside the tunnel, was solved by Eupalinos by the modification of driving a V-shaped deviation, by which he approached the target correctly and succeeded in making an exact breakthrough. The level of the tunnel was defined accurately in the initial design. The trench on the east side of the tunnel was also part of the initial design and was excavated simultaneously with the tunnel itself: it facilitated proper ventilation during the excavation. No more than four years were needed to finish construction.Originaltitel: More light in the tunnel of Eupalinos Die am Tunnel des Eupalinos, einem singulären Monument und Teil der archaischen Wasserleitung von Samos, durchgeführten Restaurierungsmaßnahmen und aus diesen resultierende neue Erkenntnisse, insbesondere zur Auskleidung des Stollens, werden in kurzer Form vorgestellt. Zudem werden neue Hypothesen zum Entwurf der Anlage und dessen Umsetzung vorgestellt. Die Trassierung des Tunnels wurde zunächst mit Gerüsten auf dem Bergrücken markiert und anschließend zum Zweck des genauen Vortriebs mit zwei Lichtsignalen ins Berginnere übertragen, von denen eines sich nördlich auf der stadtfernen Bergflanke und das andere südlich auf einem hölzernen Turm in Meeresnähe befand. Im nördlichen Stollen führte steter Wasserfluss zu hoher Luftfeuchtigkeit und die resultierende dunstige Atmosphäre innerhalb der Anlage zum Verlust des Lichtsignals; dieses Problem löste Eupalinos, indem er die Trassierung von der Achslinie abweichend zu einer flachen V-Form modifizierte, durch die sich der Vortrieb korrekt dem Zielpunkt annäherte und ein exakter Durchbruch erreicht wurde. Das Bodenniveau des Tunnels wurde bereits im ursprünglichen Entwurf genau bestimmt. Der Graben an seiner Ostseite war ebenfalls bereits Teil dieses Entwurfs und wurde zeitgleich mit dem Tunnel angelegt; er ermöglichte die angemessene Bewetterung des Vortriebs. Die Bauzeit betrug maximal vier Jahre.Πρωτότυπος τίτλος: More light in the tunnel of Eupalinos Παρουσιάζονται εν συντομία τα νέα στοιχεία που προέκυψαν από τις εργασίες αποκατάστασης της σήραγγας του Ευπαλίνου, ενός μοναδικού μνημείου, το οποίο είναι τμήμα του αρχαϊκού υδραγωγείου της Σάμου, καθώς και τα νέα στοιχεία που προέκυψαν από αυτές, ιδίως σχετικά με την επένδυση των τοιχωμάτων της στοάς. Προτείνονται επίσης νέες υποθέσεις για τον σχεδιασμό και την κατασκευή της σήραγγας. Η χάραξη έγινε αρχικά πάνω στις πλαγιές του λόφου με τη βοήθεια ενός επιμήκους ικριώματος και μεταφέρθηκε στη συνέχεια στο εσωτερικό του. Για να διασφαλιστεί η ακρίβεια της εκσκαφής, χρησιμοποιήθηκαν δύο φωτεινές πηγές: μία προς βορρά στην πλαγιά του απέναντι λόφου και μία προς νότο στην κορυφή ενός ξύλινου πύργου στην παραλία. Το πρόβλημα που προέκυψε από την απώλεια του βόρειου σήματος λόγω της υψηλής υγρασίας και της αποπνιχτικής ατμόσφαιρας, που δημιούργησε η συνεχής ροή νερού, επιλύθηκε από τον Ευπαλίνο με την τροποποίηση της χάραξης του βόρειου κλάδου με μια παράκαμψη σχήματος V. Έτσι προσέγγισε ακριβώς τον στόχο και πέτυχε την συνάντηση των δύο κλάδων. Η στάθμη της σήραγγας ορίστηκε με ακρίβεια κατά τον αρχικό σχεδιασμό. Η τάφρος στην ανατολική πλευρά της σήραγγας ήταν επίσης σχεδιασμένη εξ αρχής και διανοίχτηκε ταυτόχρονα με τη σήραγγα προκειμένου να εξασφαλιστεί ο αερισμός στο μέτωπο της εκσκαφής. Ο χρόνος κατασκευής της σήραγγας δεν ξεπέρασε τα τέσσερα χρόνια.