Clparraa

Solo disponible en BuenasTareas
  • Páginas : 21 (5039 palabras )
  • Descarga(s) : 0
  • Publicado : 9 de noviembre de 2010
Leer documento completo
Vista previa del texto
Original Research
Prognostic Value of the Pulmonary Dead-Space Fraction During the Early and Intermediate Phases of Acute Respiratory Distress Syndrome
Joan M Raurich MD PhD, Margalida Vilar MD, Asuncion Colomar MD, Jordi Ibanez MD PhD, ´ ´˜ Ignacio Ayestaran MD, Jon Perez-Barcena MD, ´ ´ ´ and Juan A Llompart-Pou MD

BACKGROUND: Little is known about the alveolar dead-space fraction afterthe first week of acute respiratory distress syndrome (ARDS). We measured the dead-space fraction in the early phase (first week) and the intermediate phase (second week) of ARDS, and evaluated the association of dead-space fraction with mortality. METHODS: We prospectively measured dead-space fraction and other variables in 80 intubated patients during the early phase of ARDS and in 49 patientsduring the intermediate phase. We used multiple logistic regression analysis to evaluate data. The primary outcome was in-hospital mortality. RESULTS: In the early and intermediate phases the dead-space fraction was higher in patients who died than among those who survived (dead-space fraction 0.64 0.09 vs 0.53 0.11, P < .001, and 0.62 0.09 vs 0.50 0.10, P < .001, respectively). In both the early andintermediate phases the dead-space fraction was independently associated with a greater risk of death. For every dead-space-fraction increase of 0.05 the odds of death increased by 59% in the early phase (odds ratio 1.59, 95% confidence interval 1.18 –2.16, P .003) and by 186% in the intermediate phase (odds ratio 2.87, 95% confidence interval 1.36 – 6.04, P .005). Age and Sequential OrganFailure Assessment score were also independently associated with a greater risk of death in both phases. CONCLUSIONS: Increased alveolar dead-space fraction in the early and intermediate phases of ARDS is associated with a greater risk of death. Key words: acute respiratory distress syndrome; ARDS; respiratory dead space; mechanical ventilation; survival. [Respir Care 2010;55(3):282–287. © 2010 DaedalusEnterprises]

Introduction The acute respiratory distress syndrome (ARDS) is physiologically characterized by a right-to-left intrapulmonary shunt, which leads to hypoxemia,1 and by an early increased physiologic dead-space fraction, which impairs carbon dioxide excretion.2,3 Though the level of hypoxemia is not always correlated with mortality,2,4-7 an early

increase in dead-space fractionis a risk factor associated with higher mortality in ARDS patients.2,4,5,8 Approximately 60% of patients with ARDS fail to clinically improve and deteriorate after 1 week of mechanical ventilation.9 Dead-space fraction remains elevated during the first week of ARDS10,11 (the early phase), but little is known about dead-space and its relationship to outcome

SEE
The authors are affiliated withthe Intensive Care Unit, Hospital Universitario Son Dureta, Palma de Mallorca, Illes Balears, Spain. The authors have disclosed no conflicts of interest. Correspondence: Joan M Raurich MD PhD, Intensive Care Unit, Hospital Universitario Son Dureta, Calle Andrea Doria 55, 07014, Palma de Mallorca, Illes Balears, Spain. E-mail: joan.raurich@ssib.es.

THE

RELATED EDITORIAL

ON

PAGE 350during the second week of ARDS (the intermediate phase). Only 2 studies (which included a small number of patients) have measured dead-space fraction over the course of ARDS and related it to mortality.12,13 We speculated that the measurement of dead-space fraction during the second week of ARDS could be useful as

282

RESPIRATORY CARE • MARCH 2010 VOL 55 NO 3

PROGNOSTIC VALUE

OF THEPULMONARY DEAD-SPACE FRACTION DURING ARDS
Minute volume was measured with a Wright spirometer. Quasistatic respiratory compliance was calculated with standard methods from measurements made during the collection of expired carbon dioxide. It was calculated as the value obtained by dividing the difference between the VT (in mL) and the volume compressed in the ventilator circuit (in mL) by the...
tracking img