Susan Pamela Drblik

Cellular immunity is activated and a TH-2 response is associated with early wheezing in infants after bronchiolitis

OBJECTIVE To determine whether abnormalities of cellular immunity are present and linked to early wheezing after bronchiolitis. METHODS We prospectively studied 26 infants hospitalized for a first episode of bronchiolitis and without any prior immune, cardiac, or respiratory disease. Blood was obtained at the time of enrollment and 5 months later for the assessment of the total cellular and differential counts, CD4+ (helper) and CD8+ (suppressor/cytotoxic) lymphocytes, and the activation markers CD23 (low-affinity immunoglobulin E receptor) and CD25 (interleukin-2 (IL-2) receptor). The cytokines interferon gamma (T-helper (TH) type-1 cytokine) and IL-4 (TH-2) were measured in plasma and in vitro after stimulation with IL-2 or with the house-dust mite (Dermatophagoides farinae) antigen. A daily log of episodes of wheezing was kept by parents after discharge. RESULTS We found an increase in blood eosinophils, an increased percentage of CD4+, CD25+, and CD23+ lymphocytes in subjects at 5 months compared with the time of bronchiolitis and with healthy subjects of the same age (p < 0.05). Plasma IL-4 levels, although not different from those of healthy subjects, also increased significantly. Peripheral blood lymphocytes from infants who wheezed produced more IL-4 in vitro, 5 months after bronchiolitis, in response to D. farinae antigen. In babies who wheezed, a positive correlation was found between the total number of days that wheezing occurred and the blood eosinophil count. Babies who wheezed more often (> 20 days) had more peripheral blood basophils and eosinophils, and peripheral blood lymphocytes obtained from these subjects at the time of bronchiolitis produced less interferon gamma on stimulation with IL-2. CONCLUSIONS Bronchiolitis is followed by activation of cellular immunity, and early wheezing in infants is associated with a TH-2 response.

Ventriculo-atrial time interval measured on M mode echocardiography: a determining element in diagnosis, treatment, and prognosis of fetal supraventricular tachycardia

Objective To determine whether M mode echocardiography can differentiate fetal supraventricular tachycardia according to the ventriculo-atrial (VA) time interval, and if the resulting division into short and long VA intervals holds any relation with clinical presentation, management, and fetal outcome. Design Retrospective case series. Subjects 23 fetuses with supraventricular tachycardia. Main outcome measures A systematic review of the M mode echocardiograms (for VA and atrioventricular (AV) interval measurements), clinical profile, and final outcome. Results 19 fetuses (82.6%) had supraventricular tachycardia of the short VA type (mean (SD) VA/AV ratio 0.34 (0.16); heart rate 231 (29) beats/min). Tachycardia was sustained in six and intermittent in 13. Hydrops was present in three (15.7%). Digoxin, the first drug given in 14, failed to control tachycardia in five. Three of these then received sotalol and converted to sinus rhythm. All fetuses of this group survived. Postnatally, supraventricular tachycardia recurred in three, two having Wolff-Parkinson-White syndrome. Four fetuses (17.4%) had long VA tachycardia (VA/AV ratio 3.89 (0.82); heart rate 226 (10) beats/min). Initial treatment with digoxin was ineffective in all, but sotalol was effective in two. Heart failure caused fetal death in one and premature delivery in one. All three surviving fetuses had recurrences of supraventricular tachycardia after birth: two had the permanent form of junctional reciprocating tachycardia and one had atrial ectopic tachycardia. Conclusions Careful measurement of ventriculo-atrial intervals on fetal M mode echocardiography can be used to distinguish short from long VA supraventricular tachycardia and may be helpful in optimising management. Digoxin, when indicated, may remain the drug of choice in the short VA type but appears ineffective in the long VA type.

Flow velocity profile of the fetal aortic isthmus through normal gestation

Experimental and clinical evidence have demonstrated that an increase in resistance to placental blood flow causes changes in aortic isthmic diastolic flow profile before any significant modification is observed in umbilical artery Doppler waveforms. To identify these abnormal flow profiles, the objective of this study was to document the normal flow profile in the aortic isthmus throughout pregnancy. The study included 81 normal fetuses from 17 to 39 weeks of gestation. On the isthmic flow profile, an index, named the balance index, was calculated: (peak systolic--end-diastolic velocities/forward--reverse flow velocity integrals). Before 20 weeks of gestation, a forward flow was recorded throughout the cardiac cycle and the diastolic deceleration phase was gradual and smooth. After 20 weeks, an incisura appeared at end-systole that progressively increased, and by 30 weeks of gestation a brief reverse diastolic flow was constantly recorded. The balance index increased slightly throughout gestation. Color flow mapping demonstrated that the reverse flow observed late in gestation in the isthmus was coming from the ductus arteriosus. In conclusion, the morphology of the Doppler flow velocity waveform of the fetal aortic isthmus changes with gestation. The proposed balance index may be useful in identifying fetuses with disturbed peripheral hemodynamics.

Factors affecting the prognosis of Ebstein's anomaly during fetal life

BACKGROUND The echocardiographic criteria that have been used to evaluate severity of Ebsteins anomaly in utero are the same as those applied after birth. OBJECTIVE The objective of this study was to establish prognostic criteria that take into account the peculiarities of the fetal hemodynamics. METHOD The video recordings of eight fetuses with Ebsteins anomaly were retrospectively reviewed. RESULTS The following indexes had no prognostic significance either on fetal or neonatal outcome: the ratio of functional tricuspid opening over the diameter of the annulus, the degree of displacement of the tricuspid valve opening, and the degree of tricuspid regurgitation. The index of severity (based on the surfaces of right atrium + atrialized right ventricle) and the cardiothoracic ratio had a significant impact only on neonatal survival. The smallest fossa ovalis were found in two fetuses who had hydrops. Fetuses who reached term without problems had higher left ventricular outputs. A positive linear correlation was found between the z score of the left ventricular output and the size of the fossa ovalis (r = 0.81, p < 0.05). CONCLUSION The prognosis of Ebsteins anomaly during fetal life is not influenced by criteria described for postnatal life and may be related to factors that control the volume load of the left ventricle.

Comparison of inhaled terbutaline administered by either the Turbuhaler dry powder inhaler or a metered-dose inhaler with spacer in preschool children with asthma.

We compared the bronchodilator response of terbutaline delivered either by a dry powder inhaler, the Turbuhaler, or by a metered-dose inhaler attached to a Nebuhaler inhaler in 10 children with stable asthma who were 3 to 6 years of age. The bronchodilator response did not differ between the two inhalational devices. The dry powder inhaler Turbuhaler is a suitable alternative to a metered-dose inhaler in the delivery of terbutaline to preschool children with stable asthma if adequate inhalational technique is used.

Doppler velocimetric indices from the abdominal and placental ends of the umbilical artery of growth-restricted fetuses

In normal pregnancies, as gestation advances, a progressive decrease is observed in the difference between Doppler indices recorded at the 2 extremities of the umbilical cord. The purpose of this study was to determine whether the same pattern is observed in pregnancies complicated by intrauterine growth restriction (IUGR).

Assessment of fetal pulmonic stenosis by ultrasonography

This study was designed to determine (1) the value of Doppler echocardiography in depicting the presence of a fetal pulmonary stenosis, (2) its reliability in the assessment of the severity of the lesion, and (3) the usefulness of additional markers from the left side of the heart as criteria of severity. Fourteen pregnant ewes were included in this study (gestational age, 90 to 120 days). Banding of the fetal main pulmonary artery created mild (n = 3), moderate (n = 3), and severe (n = 5) stenosis. Three lambs were sham operated. Intrauterine fetal Doppler echocardiographic data obtained 15 days after surgery were compared with preoperative values. Peak velocities recorded through the band increased linearly from baseline in the groups with mild and moderate stenosis but did not show any further increase in the group with severe stenosis. Compared with the sham-operated group, right ventricular output in the group with stenosis was either similar or reduced significantly. The increase in right ventricular free wall thickness was significantly greater in the groups with stenosis compared with that of the sham-operated group; the correlation with the degree of severity was r = 0.65 and p < 0.05. A A stronger positive correlation was found between the severity of stenosis and aortic valve diameters: r = 0.82 and p < 0.01. The strongest correlation was found for right ventricular/left ventricular outputs (r = 0.92; p < 0.001). Thus Doppler peak velocities through the obstruction can help detect pulmonic stenosis but are not reliable for the assessment of its severity during fetal life. Other ultrasound measurements such as the size of the aortic anulus and especially the ratio of right ventricular/left ventricular output could be used as sensitive markers of the severity of stenosis.

A Protocol for Aerosol Therapy in Acute Hospitalized Asthmatics

The most important element in the treatment of acute hospitalized asthmatics is salbutamol administered via wet nebulization prescribed usually on a subjective evaluation of the patients status. This study outlines a novel protocol that incorporates the FEV1 variable as the major objective parameter in a feedback loop. Data from patients admitted in the year prior to the initiation of the protocol (N = 348) were compared with similar data from patients hospitalized the year following institution of the protocol (N = 238). There were no withdrawals from the protocol due to adverse effects nor were there any deteriorations requiring ICU admission. A significant decrease in the length of hospitalization and the number of salbutamol prescriptions per hospitalization was observed after, relative to before, institution of the protocol (2.2 vs. 2.6 days; 2.3 vs. 3.8; p < .05, respectively). It is concluded that this protocol is safe and efficient, and may also be more efficacious than a nonstandardized approach for treating the hospitalized asthmatic child.