22 nd European Conference on General Thoracic Surgery Copenaghen, 15 th -18 th June, 2014 DEFINING KEY FEATURES IN THE DEVELOPMENT OF COMPUTER -ASSISTED DEVICE FOR DIGITAL CHEST DRAIN SYSTEM Rita Daniela Marasco GENERAL THORACIC SURGERY DEPARTMENT I.R.C.C.S. – C.R.O.B. REFERRAL CANCER CENTER OF BASILICATA Rionero in Vulture, Italy

In patients submitted to pulmonary resection the length of post-operative stay is mainly due to air leaks and chest tube removal, which are the main factors that delay hospital discharge

Singhal S, Ferraris VA, Bridges CR, Clough ER, Mitchell JD, Fernando HC, Shrager JB. Management of Alveolar air leaks after pulmonary resection, Ann Thorac Surg, 2010; 89; The most common complication following elective Thoracic Surgery procedures and the first cause of related hospital stay expenses is a prolonged air leak (PAL ≥ 5 p.o. days)

“The main advantage of providing objective and reproducible data is to decrease inter-observer variability of the air leak assessment, one of the principle factors in delaying chest tube removal.” Brunelli A, Salati M, Refai M, Sabbatini A. Evaluation of a new chest tube removal protocol using digital air leak monitoring after lobectomy: a prospective randomized trial. Eur J Cardiothorac Surg 2010;37:56-60

The purposes of a digital chest drain system are: ¤ identification of significant air flows ¤ recognition of a prolonged air leak ¤ prediction of a late air leak ¤ differentiation of an active air leakage from a “pleural space effect” ¤to ensure the best management

EVO DRENTECH ® PALM EVO

COLLECTION CHAMBER ¤great stability of the support base (lower overturning risk - no doubts about daily drainage) ¤great capacity (3000 ml) ¤wider and softer tubing material ¤water seal chamber available (for immediate comparison with a traditional analogue chest drain)

CONTROL UNIT

¤Real time assessment and storage of intrapleural pressures span (pe MAX - pi MIN ) (+15→-30 cmH 2 O) and air flows (ml min -1 ) (every 60 sec) ¤Air leak mean hourly value (AVG 1H) history ¤ Graphic form of intrapleural pressures, air leaks and applied suction levels, ON BOARD UP TO 99 HOURS!

¤Easy download of all real time data and graph forms ¤Suction levels up to -60 cmH 2 O ¤Real “no suction” mode available (“pump off”) ¤When the suction pump is deactivated, it's no more possible to make air leakage measurement!

ACTIVE AIR LEAKS An active air leak is a significant air flow characterized most of the time by instantaneous air flow “spikes” higher than 150 ml/min. Moreover it’s associated to high differential pleural pressures (>10 cmH 2 0), that is expression of a pleural space constantly feeded by a mean air flow greater than 20 ml/min.

ACTIVE AIR LEAK

Brunelli A, Cassivi SD, Salati M, Fibla J, et al. Digital measurement of air leak flow and intrapleural pressures in the immediate postoperative period predict risk of prolonged air leak after pulmonary lobectomy. Eur J CardioThor Surg 39(2011) Patients with a flow lower than 50 ml min -1 and a differential pleural pressure lower than 10 cm H 2 O had a PAL incidence of only 4%. On the other hand, those with a flow greater than 50 ml min -1 and a large differential showed a risk of PAL as high as 52%. a. DP < 10 + Flow < 50: 4% (3/73). b. DP > 10 + Flow < 50: 15% (5/33). c. DP 50: 36% (5/14). d. DP > 10 + Flow > 50: 52%(13/25)

AVG 1h Real Time Flows pe MAX Δp (ml/min) (ml/min) (cmH 2 O) (cmH 2 O) Low risk: 0-1 < 50 < Grey zone: High risk: 2-5 > 150 > 1 > 10 PAL: IDENTIFICATION OF A HIGH RISK POPULATION (37 pts, 47 downloads from august 2013 to june 2014)

PROLONGED AIR LEAKS The persistence of a mean air flow > 20 ml/min and Δp>10 cmH 2 0 over the 4 th p.o. day (96 th hour) can predict a prolonged air leak. The greater the flow and Δp value are at the beginning the longer the air leakage is.

PROLONGED AIR LEAK

AIR LEAK RESOLUTION

LATE AIR LEAKS A late air leak is an active air flow arising later than the 72 nd post-operative hour. It’s predicted by a progressive pressure curves divergence (i.e. an increase of Δp > 5 cmH 2 0) which usually anticipates the appearance of a significant air flow.

LATE AIR LEAKAGE

PLEURAL SPACE EFFECT It’s defined as an increase of mean differential pleural pressure (Δp: pe MAX – pi MIN ) mainly due to an inspiratory pressure decrease, following a pleural space developement Δφ < 10 ml/min Δpm: 15 – 25 cmH 2 O pi MIN : cmH 2 O “A digital chest drain system ensuring a continuous air flow and pleural pressures measurement could clearly identify a pleural space effect, avoiding the frequent misinterpretation with an active air leak and allowing to safely remove a chest tube at the right time.” Rita Daniela Marasco, Gabriella Giudice, and Cosimo Lequaglie. How to distinguish an active air leak from a pleural space effect. Asian Cardiovasc Thorac Ann 2012;20:

PLEURAL SPACE EFFECT IIIII

Vacuum units cannot provide a direct air flows measurement; it activates an umpredictable numbers of times per minute and calculates the “real time air flow” dividing the sum of sucked volumes by the numbers of activations. In a pleural space effect the air flow through the pleura is totally umpredictable and sporadic; spreading an average volume over a given time interval, the system may graphically outline an omogeneous, gross distribution of air flow spikes suggesting the idea of a continuous air leak which actually does not exist!

CONCLUSIONS A digital system covering a 99 hours time interval in the p.o. period measuring, recording and showing on board air flows, pressures, suction levels has all the requested key features to recognize active, prolonged and late air leaks.

Redax Drentech Palm EVO is a digital chest drain that - although indirectly - can identify a significant air flow, recognize a PAL, predict a late air leak; its trasportable vacuum unit allows to apply different suction levels, in order to handle and treat in the best way both a prolonged air leak and a pleural space applying the right suction level at the right time.

Actually, the system is not provided with a flow sensor, and the pump off mode doesn’t allow to follow the air flow trend; therefore it was difficult in our experience to distinguish an active air leak from a pleural space effect. Nevertheless, the collection chamber is equipped with a water seal, so that it could be helpul in ambiguous cases to identify a significant air flow.

Thank you all for your kind attention! Daniela Marasco