Critical Care

, 9:P89 | Cite as

Diagnostic test of the desaturation index and the calculated desaturation index to identify acute lung injury and/or acute respiratory distress syndrome at the bedside

  • G Vazquez de Anda
  • J Arzate Villafaña
  • J Talavera Piña
  • S Laraza
  • J Gutierrez
  • D Rodriguez Cadena
Poster presentation

Keywords

Mechanical Ventilation High Altitude Respiratory Failure Acute Lung Injury Acute Respiratory Distress Syndrome 

Introduction

We have previously shown that the desaturation index (DI) and the calculated desaturation index (Dic) have a statistical correlation with several indices of gas exchange and with lung infiltrates on the thorax X-ray. However, the utility of the DI and Dic as a diagnostic tool has never been tested. The aim of this study is therefore to determine the capability of the DI and the Dic: to identify acute lung injury (ALI) and/or acute respiratory distress syndrome (ARDS) at the bedside.

Patients and methods

Patients with and without ALI and/or acute respiratory failure (ARDS) were followed during the period of mechanical ventilation. Every morning, blood gases analysis and thorax X-rays were taken and definitions for ALI/ARDS were completed according to the American–European Consensus Conference. We registered the positive end expiratory pressure, inspired fraction of oxygen (FiO2) and arterial saturation by pulse oximetry (SpO2) to calculate the Dic. Then, in order to determine the DI, all patients were subjected to breathe 100% oxygen, with a gradual reduction of the FiO2 to 21%, in steps of 20% lasting 8 min each, and at each step the SpO2 was registered (we stop the maneover after reaching 85% of the SpO2). Finally, we calculated the DI according our equation that has been described previously. Two or more quadrants with infiltrates on the thorax X-ray and PaO2/FiO2 ratio (adjusted to high altitude) lower than 221 mmHg were considered positive for ALI/ARDS. The sensitivity and specificity were calculated according to conventional equations.

Results

During the study period, 198 ALI/ARDS definitions were completed. Table 1 presents the sensitivity and specificity tests for the DI and the Dic. Results are shown as the percentage and confidence interval.

Table 1

 

Pao2/FiO2

Thorax X-ray

ALI/ARDS

DI sensitivity

0.86 (0.78–0.91)

0.77 (0.69–0.84)

0.87 (0.78–0.92)

DI specificity

0.84 (0.75–0.89)

0.85 (0.76–0.91)

0.83 (0.74–0.87)

DIc sensitivity

0.93 (0.87–0.97)

0.85 (0.77–0.90)

0.99 (0.95–1)

DIc specificity

0.82 (0.74–0.89)

0.85 (0.76–0.91)

0.93 (0.86–0.97)

ALI, acute lung injury; ARDS, acute respiratory distress syndrome; DI, desaturation index; Dic, calculated desaturation index.

Conclusion

We conclude that the DI and the Dic, which are noninvasive indices, have an acceptable sensitivity and specificity to identify ALI/ARDS patients at the bedside.

Copyright information

© BioMed Central Ltd 2005

Authors and Affiliations

  • G Vazquez de Anda
    • 1
    • 2
  • J Arzate Villafaña
    • 1
    • 2
  • J Talavera Piña
    • 2
  • S Laraza
    • 1
  • J Gutierrez
    • 1
  • D Rodriguez Cadena
    • 2
  1. 1.ISSEMYM Medical CenterTolucaMexico
  2. 2.Universidad Autonoma del Estado de MexicoTolucaMexico

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