The Value of Pulsus Paradoxus in Assessing the Child With Status Asthmaticus

Abstract

The presence of pulsus paradoxus (PP) in 13 episodes of status asthmaticus in 12 children, ages 13 months to 15 years, was compared sequentially to a clinical score, peak expiratory flow rate (PEFR), heart rate, arterialized capillary pH, carbon dioxide pressure (Pco2), and the ratio of inspired oxygen to oxygen pressure (FIo2)/Po2) during the first 48 hours following admission. There was a significant correlation (P < .01) between the presence of a PP (≥ 5 mm Hg) and the clinical score (r = .79), PEFR (r = .55), and heart rate (r = .49). This was particularly striking when the PP was ≥ 20 mm Hg. There was no significant correlation between the mean PP and the Pco2 or FIo2/Po2, ratio. However, a mean Pco2, exceeding 40 mm Hg was associated with a highly significant (P < .005) difference in mean PP (22.2 mm Hg) compared to the mean PP (12.2 mm Hg) when the Pco2 was below 40 mm Hg. Although the PP technique can easily be learned by physician and nursing personnel, there are potential problems. The difficulties in children are compared to those in adults. The PP is a valuable clinical tool in assessing the severity of airway obstruction in status asthmaticus. The presence of a PP, particularly greater than 20 mm Hg, is associated with moderate to severe airway obstruction. In conjunction with the overall clinical status of the patient and frequent blood gas determinations, the PP allows for better evaluation of the patient with status asthmaticus.

The Use of Point‐of‐Care Ultrasound to Evaluate Pulsus Paradoxus in Children With Asthma

“…Measurement of PP during acute asthma exacerbations is currently recommended by national and international guidelines 11,17 and is one of the few objective bedside measures for assessment of asthma severity and the response to treatment. 4,8,18 However, manual determination of PP has been noted to be time-consuming to perform, 19 has variable interphysician consistency, 20 is difficult to obtain in a tachypneic child, 4 and is rarely used in clinical practice. 18,21 Furthermore, the ability of physicians to consistently and effectively measure blood pressure correctly has been reported to be poor.…”

“…2 Although there is no consensus regarding the underlying pathophysiologic mechanisms of PP, 2,5 biventricular interdependence likely has an important role in both pericardial tamponade and acute asthma. 3 Prior studies evaluating the use of PP in children with asthma have found that PP of 15 mm Hg or greater predicts the need for hospitalization 6 and is associated with increased carbon dioxide pressure levels, [7][8][9] a decreased peak expiratory flow rate, 8 and decreased oxygen saturation (SpO 2 ). 10 National asthma guidelines for adults and children correlate PP with the severity of asthma: "absence of PP" (<10 mm Hg) in mild asthma; "may be present" (10-25 mm Hg) in moderate asthma; and "often present" (>25 mm Hg in adults and 20-40 mm Hg in children) in severe asthma.…”