Comparison of Pre- and Post-inhaled Nitric Oxide (iNO) Therapy 689 RESULTS Clinical characteristics Clinical characteristics of the patients enrolled during the Table 1. Clinical characteristics and survival rates during peri- ods I and II two periods are given in Table 1. The rates of inborn delivery and prenatal diagnosis were significantly higher during P2 than during P1. No significant differences were observed between the two periods in terms of any other clinical char- acteristics. Change in survival rate The overall survival rate of the 48 CDH patients was 69% (33 of 48), and the survival rate increased from 53% (9 of 17) during P1 to 77% (24 of 31) during P2 (Table 1). All deaths (15 patients) occurred before six days of life (2-146 hr), and eight patients died before 24 hr of life. All deaths occurred as a result of PPH or refractory hypoxemia. When survival rates over the first 7 days after birth were analyzed using Ka- plan-Meier curves for the two periods (not shown), the sur- vival rate for P2 was higher than that for P1, but without a significant difference (p=0.096). However, after adjusting for the initial clinical characteristics (sex, gestational age, birth weight, Apgar score at 5 min, significant associated anoma- lies, prenatal diagnosis, inborn delivery, polyhydramnios, and liver herniation), this difference between the two periods achieved a significance (p=0.033) (Table 2). Thirty-seven of the 48 patients (P1, 13 of 17; P2, 24 of 31) underwent an operation (Table 3). Postoperative survival rates increased Table 2. Changes in survival rates between periods I and II after adjusting for the initial clinical characteristics* (by Cox regres- sion analysis) Hazard ratio 95% CI Period I Period II 1 0.135 0.021-0.846 p value 0.033 Period I (n=13) 9 (69%) - - - - 4 (31) 18.5±16.6 (6-43) 23.4±15.4 (2-47) 15.1±12.9 (2-47) 20.3±5 (14-26) 9.86±4 (4-17) 0.74±0.28 (0.4-1) Period II (n=24) 24 (100%)* 7 (30) 31±28.1 (4-96) 6 (25) 193±130 (16-408) 12 (50) 34.4±26.4 (8-96) 39.5±22.9 (10-96) 38.7±23.3 (10-96) 19.1±3.8 (13-25) 9.87±3.1 (6-20) 0.61±0.2 (0.4-1) Period I (n=17) Period II (n=31) Total (n=48) 7 (41) 23 (74)* 30 (63) 9 (53) 24 (77) 33 (69) 2.94±0.73 3.09±0.56 3.03±0.62 (1.3-4) (1.9-4.1) (1.3-4.1) 38.5±3.1 38.7±1.8 38.7±2.3 (29-42) (34-42) (29-42) 9 (53) 17 (55) 26 (54) 6.2±2.1 6.7±1.8 6.9±1.6 (1-9) (2-9) (1-9) 23 (74) 9 (29) 4 (68) 5 (16) 23 (74) 3 (10) 8 (26) 5 (16) 9 (29) 29 2 24 (77) 27 (56) 12 (25) 8 (17) 7 (15) 38 (79) 3 (6) 12 (25) 7 (15) 13 (27) 44 (92) 4 (8) 33 (69) General characteristics Inborn, n (%) Male gender, n (%) Birth weight (kg) (range) Gestation age (wk) (range) Vaginal delivery, n (%) Apgar score (5-min) (range) CDH characteristics Prenatal diagnosis, n (%) 4 (24) Polyhydramnios, n (%) 3 (18) Significant associated 4 (35) anomalies , n (%) Side of defect, n (%) Right 2 (12) Left 15 (88) Bilateral or central 0 (0) Herniation of liver, n (%) 4 (24) Associated pneumothorax, n (%) 2 (12) Documented PPHN, n (%) 4 (24) Onset of respiratory distress, n (%) Early (≤24 hr) 15 Late (>24 hr) 2 Survivors, n (%) 9 (53) Survivors after operation, n (%) Preoperative iNO therapy, n (%) Duration (hr) (range) Postoperative iNO therapy, n (%) Duration (hr) (range) Preoperative HFOV therapy, n (%) Duration (hr) (range) Profiles of preoperative respiratory care Duration of intubation (hr) (range) Duration of ventilator care (hr) (range) PIP (max. cmH2O) (range) MAP (max. cmH2O) (range) FiO2 (max.) (range) *p=0.032 vs. Period I; p=0.001 vs. Period I; Associated anomalies ex- cluding patent ductus arteriosus and atrial septal defect. PPHN, persistent pulmonary hypertension of the newborn; CDH, con- genital diaphragmatic hernia. *Sex, gestational age, birth weight, Apgar score at 5 min, significant associated anomalies, prenatal diagnosis, inborn delivery, polyhydram- nios, and liver herniation. CI, confidence interval. Table 3. Pre- and postoperative respiratory management of patients who underwent operation *p=0.011 vs. Period I; p=0.041 vs. Period I; p=0.001 vs. Period I. HFOV, high-frequency oscillatory membrane oxygenation; PIP, peak inspiratory pressure; MAP, mean airway pressure; FiO2, fraction of inspired O2.