# Continuous Noninvasive Measurement of Pulsus Paradoxus Complements Medical Decision Making in Assessment of Acute Asthma Severity: Cost-Effectiveness

The interrater reliabilities, as assessed with intraclass correlation, are listed in Table 3. Neither the composite nor any of the subscales met our criterion for reliability (0.80). However, the estimated mean of the composite score did meet our criterion, as did the mean for OD at pretreatment. The mean total score, which was the only measure that met our criteria for reliability, was marginally predictive of AT-PP (Table 3), indicating that higher means generally predicted higher AT-PP. Examination using hierarchical linear modeling further revealed that while physicians did not show agreement in their absolute scores as measured by ICC, their composite score and one subscore (ie, OD) did significantly relate to AT-PP, as indicated by a significant mean slope (Table 4). This indicates that physicians agree on perceived changes in a composite assessment and OD, which are correlated to changes in AT-PP. This was almost also true for prolonged expiratory phase. inhalers online

Treating physician-based disposition was not error-free, contributing to increased costs. The actual mean cost per patient was approximately $3,057, compared to the $2,813 that would have been obtained with perfect sensitivity and specificity (ie, accuracy). Relying on AT-PP measurement alone in this study would have increased care costs to $3,285, which is reflected in Figure 2, top, A, in the cost-of-care function at the optimal AT-PP threshold of 11.3 mm Hg. However, the hypothetical cost for combined AT-PP and physician-based disposition was $2,838, assuming that physician-based disposition would have been improved with AT-PP. Figure 3 shows that the majority of both derived and observed respiratory rates fell within ± 5 breaths/min over a range of respiratory rates from 12 to 30 breaths/min from both the pretreatment and posttreatment data sets. However, the respiratory rate derived from the AT-PP monitor failed to predict those obtained by the research assistants, as indicated by the lack of a significant relationship between derived and observed respiratory rate during pretreatment (slope, 0.086; intercept, 21.13; F = 0.199; p = 0 0.66) and during posttreatment (slope, —0.147; intercept, 24.78; F = 1.178; p = 0.28).

**Table 3—Interrater Reliability of Objective Scoring**

Scale (Transformation) | Interrater Reliability | Estimated Reliability of Mean | ||

Pre-TX ICC | Post-TX ICC | Pre-TX ICC | Post-TX ICC | |

Total (sqrt) | 0.732 | 0.692 | 0.845! | 0.818! |

OD (sqrt) | 0.697 | 0.586 | 0.821! | 0.739 |

Sternocleidomastoid muscle use (inv) | 0.543 | 0.415 | 0.704 | 0.587 |

Prolonged expiratory phase (sqrt) | 0.595 | 0.611 | 0.746 | 0.758 |

Respiratory rate (sqrt) | 0.607 | 0.575 | 0.756 | 0.730 |

Heart rate (sqrt) | 0.574 | 0.729 | 0.597 | 0.747 |

Accessory muscle use (log) | 0.658 | 0.538 | 0.794 | 0.699 |

Air entry (log) | 0.110 | 0.422 | 0.198 | 0.593 |

Work of breathing (log) | 0.534 | 0.581 | 0.697 | 0.735 |

Mental status (inv) | 0.328 | 0.557 | 0.493 | 0.715 |

Cerebral function (inv) | 0.278 | 0.328 | 0.435 | 0.494 |

**Table 4—Bivariate Relationships Between Objective Scoring and AT-PP**

Repeated-Measures ANOVA (Transformation) | Slope | SE | df | t Test | p Value (1-tailed) |

Mean total (sqrt) | 0.5161 | 0.2685 | 41 | 1.922 | 0.031 |

Total (sqrt) | 0.156 | 0.053 | 34 | 2.930 | 0.003! |

OD (sqrt) | 0.228 | 0.078 | 32 | 2.902 | 0.003! |

Sternocleidomastoid muscle use (inv) | 0.270 | 0.180 | 32 | 1.501 | 0.072 |

Prolonged expiratory phase (sqrt) | 0.214 | 0.079 | 32 | 2.695 | 0.006 |

Respiratory rate (sqrt) | 0.169 | 0.074 | 33 | 2.282 | 0.015 |

Heart rate (sqrt) | 0.145 | 0.080 | 34 | 1.809 | 0.040 |

Accessory muscle use (log) | 0.175 | 0.070 | 31 | 2.490 | 0.009 |

Air entry (log) | 0.165 | 0.069 | 31 | 2.396 | 0.011 |

Work of breathing (log) | 0.179 | 0.071 | 34 | 2.497 | 0.009 |

Mental status (inv) | 0.409 | 0.232 | 31 | 1.761 | 0.044 |

Cerebral function (inv) | 0.296 | 0.272 | 30 | 1.088 | 0.143 |

*Figure 3. Bland-Altman plot of the respiratory rate measured by trained bedside observers compared to the predicted respiratory rate from the AT-PP monitor.*

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