Study of multiparameter respiratory pattern complexity in surgical critically ill patients during weaning trials.
BACKGROUND
Separation from mechanical ventilation is a difficult task, whereas conventional predictive indices have not been proven accurate enough, so far. A few studies have explored changes of breathing pattern variability for weaning outcome prediction, with conflicting results. In this study, we tried to assess respiratory complexity during weaning trials, using different non-linear methods derived from theory of complex systems, in a cohort of surgical critically ill patients.


RESULTS
Thirty two patients were enrolled in the study. There were 22 who passed and 10 who failed a weaning trial. Tidal volume and mean inspiratory flow were analyzed for 10 minutes during two phases: 1. pressure support (PS) ventilation (15-20 cm H2O) and 2. weaning trials with PS: 5 cm H2O. Sample entropy (SampEn), detrended fluctuation analysis (DFA) exponent, fractal dimension (FD) and largest lyapunov exponents (LLE) of the two respiratory parameters were computed in all patients and during the two phases of PS. Weaning failure patients exhibited significantly decreased respiratory pattern complexity, reflected in reduced sample entropy and lyapunov exponents and increased DFA exponents of respiratory flow time series, compared to weaning success subjects (p < 0.001). In addition, their changes were opposite between the two phases of the weaning trials. A new model including rapid shallow breathing index (RSBI), its product with airway occlusion pressure at 0.1 sec (P0.1), SampEn and LLE predicted better weaning outcome compared with RSBI, P0.1 and RSBI* P0.1 (conventional model, R(2) = 0.874 vs 0.643, p < 0.001). Areas under the curve were 0.916 vs 0.831, respectively (p < 0.05).


CONCLUSIONS
We suggest that complexity analysis of respiratory signals can assess inherent breathing pattern dynamics and has increased prognostic impact upon weaning outcome in surgical patients.
Alexandroupolis University Hospital, Democritus University of Thrace, Dragana, Greece. papabil69@vodafone.net.gr
Vasilios E
VE
Papaioannou
Ioanna G
IG
Chouvarda
Nikos K
NK
Maglaveras
Ioannis A
IA
Pneumatikos
D000368:Aged; D016638:Critical Illness / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000503:physiopathology / Q000628:therapy*; D012121:Respiration, Artificial / Q000379:methods*; D012131:Respiratory Insufficiency / Q000503:physiopathology / Q000628:therapy*; D015656:Respiratory Mechanics / Q000502:physiology*; D013990:Tidal Volume; D015300:Ventilator Weaning / Q000379:methods*
Am J Respir Crit Care Med. 1997 Aug;156(2 Pt 1):459-65
9279224
Conf Proc IEEE Eng Med Biol Soc. 2006;2006:1462-5
17946466
Med Biol Eng Comput. 2004 Jan;42(1):86-91
14977227
J Clin Monit. 1991 Oct;7(4):335-45
1744678
Chest. 2003 Apr;123(4):1222-8
12684315
Anesthesiology. 2010 Mar;112(3):670-81
20179505
Am J Respir Crit Care Med. 1995 Dec;152(6 Pt 1):1967-76
8520764
Am J Respir Crit Care Med. 2000 Jul;162(1):319-23
10903261
J Crit Care. 2011 Jun;26(3):262-72
20869842
Chaos. 1995;5(1):82-7
11538314
Nature. 2002 Nov 14;420(6912):246-51
12432410
J Neural Eng. 2004 Mar;1(1):16-20
15876618
Eur Respir J. 2007 May;29(5):1033-56
17470624
Chest. 2001 Dec;120(6 Suppl):375S-95S
11742959
Circulation. 2000 Jun 13;101(23):E215-20
10851218
Ann Biomed Eng. 2002 May;30(5):683-92
12108842
Am J Respir Crit Care Med. 2001 Aug 15;164(4):620-6
11520726
J Appl Physiol (1985). 1988 Jul;65(1):309-17
3403474
Am J Respir Crit Care Med. 2002 May 1;165(9):1260-4
11991875
Nature. 1998 May 14;393(6681):127-8
9603516
Crit Care Med. 2006 Aug;34(8):2076-83
16755257
J Appl Physiol Respir Environ Exerc Physiol. 1981 Feb;50(2):299-306
7204203
Am J Physiol Heart Circ Physiol. 2000 Jun;278(6):H2039-49
10843903
Am J Physiol Regul Integr Comp Physiol. 2005 May;288(5):R1237-47
15650124
Respir Physiol Neurobiol. 2008 Apr 30;161(2):189-96
18387347
N Engl J Med. 1989 Nov 2;321(18):1223-31
2677729
Respir Physiol. 1992 Jun;88(3):313-21
1615228
Am J Physiol. 1994 Apr;266(4 Pt 2):H1643-56
8184944
IEEE Trans Biomed Eng. 2006 Jul;53(7):1330-45
16830937
Chest. 1997 Jul;112(1):186-92
9228375
J Appl Physiol Respir Environ Exerc Physiol. 1982 Sep;53(3):644-59
7129986
N Engl J Med. 1991 May 23;324(21):1445-50
2023603
Nature. 1999 Jul 22;400(6742):360-3
10432113
Proc Natl Acad Sci U S A. 2001 Jun 19;98(13):7107-12
11416195
Neuropsychobiology. 2002;46(3):111-20
12422057
Am J Physiol Regul Integr Comp Physiol. 2007 May;292(5):R1985-93
17218438
J Appl Physiol (1985). 1996 Apr;80(4):1079-87
8926229
Am Rev Respir Dis. 1987 Jan;135(1):107-13
3800139
Am J Physiol Regul Integr Comp Physiol. 2002 Sep;283(3):R789-97
12185014
Biophys J. 2002 Jan;82(1 Pt 1):206-14
11751309
Chest. 2001 Dec;120(6 Suppl):400S-24S
11742961
Proc Natl Acad Sci U S A. 1996 Nov 26;93(24):14100-5
8943067
Crit Care Med. 1998 Nov;26(11):1817-23
9824073
Intensive Care Med. 2004 Feb;30(2):241-247
14647889
Intensive Care Med. 2001 Jan;27(1):52-8
11280673
J Appl Physiol (1985). 1991 Apr;70(4):1748-62
2055854
J Appl Physiol (1985). 1985 Nov;59(5):1515-20
4066581