Inhaled Nitric Oxide ForAcute Chest Syndrome In Adult Sickle Cell Patients: A Randomized Controlled Study
B. Maitre1,2,3,4, M. Djibre5,6, S. Katsahian2,7, A. Habibi2,8, K. Stankovic Stojanovic6,9, M. Khellaf2,10, I. Bourgeon1, F. Lionnet6,9, A. Charles Nelson2,7, L. Brochard1,11, F. Lemaire1,2, F. Galacteros2,8, C. Brun-Buisson1,2, M. Fartoukh5,6, A. Mekontso Dessap1,2,3.
On line only supplemental material
Contents:
Methodspages 2-4
eTable 1: Demographics and Baseline Characteristics of Hypoxemic Patients by Treatment page 5
eTable 2: Characteristics at Inclusion of Hypoxemic Patients by Treatment page 6
eTable 3: Effects of Inhaled Nitric Oxide Gas on primary and secondary outcomes in
hypoxemic patientspage 7
eTable 4: Safety outcomepage 8
METHODS
Design
This prospective, multicenter, double-blind, placebo-controlled, randomized, phase 2 trial was approved by our institutional review board (Comité de Protection des Personnesdansla RechercheBiomédicale Paris XII). Written informed consent was obtained before inclusion of patients. An independent data and safety monitoring board (DSMB) monitored study conduct and safety data. An unblinded independent biostatistician reported interim methemoglobin results to the DSMB to ensure that participants were not subjected to an increased risk of methemoglobinemia.
Patients
Consecutive adults (≥18 years old) with SCD presenting to the emergency department or internal medicine unit of participating centers (Henri Mondor University Hospital, Créteil, France, and Tenon University Hospital, Paris, France) with a diagnosis of ACS were screened between December 2008 and December 2012. Eligible patients were referred to the medical intensive care unit (ICU) of each participating center for inclusion in the study. Clinical and laboratory data were recorded before and during the hospital stay. Baseline individual values were considered as those measured more than one month before any clinical event and at least one month after the last transfusion. The inspired oxygen fraction (FiO2) at randomization was estimated from the oxygen flow delivered via a nasal cannula or oxygen mask [FiO2 = 0.21 + (0.03 x oxygen flow in liters per minute]. Clinical severity was assessed using the Hebbel score as modified by Lee et al[1, 2]. Pain was assessed on a visual analog scale from 0 (“no pain”) to 10 cm (“worst possible pain”), sleeping participants were not awakened to complete the VAS and a value of zero was assigned.
Randomization and blinding
Inclusion time was defined as the time when a set of study placebo or nitric oxide gas cylinders was assigned and a cylinder was opened.
iNO (Ikaria [formerly INO Therapeutics], Porcheville, France) was supplied at a concentration of 800 ppm balanced with nitrogen (99.92% grade 5 nitrogen, 0.08% pharmaceutical grade nitric oxide). Placebo study gas was 100% grade 5 nitrogen. Either nitric oxide or placebo was delivered with air and mixed with oxygen immediately prior to to achieve a constant FiO2. Concentration of NO and nitrogen dioxide (NO2) delivered in the gas mixture was continuously monitored by an alarm-equipped electrochemical NO/NO2 side-stream analyzer built into the delivery device. Participants were treated via face mask using a continuous-flow delivery system but were allowed to use nasal cannula for less than 60 minutes per day. Coded labels were applied to the study cylinders at the manufacturing site. A “blinded” version of the face mask nitric oxide delivery system blanked out and covered both the nitric oxide and nitrogen dioxide monitor displays. The placebo gas was administered in the same way and over the same time to ensure that participants and investigators remained blinded to group assignment.NO, NO2, FiO2 were monitored by an independent research nurse in each site, who monitored also venous methemoglobin levels (see below). Nurses and clinicians in charge are not aware of the results during the trial.
Study Intervention
All patients received a standardized treatment protocol, consisting of: 1) intravenous rehydratation (30 ml/kg/day); 2) nasal or face mask supplemental oxygen adjusted to maintain a continuous pulse oxygen saturation greater than 95%; 3) analgesia with intravenous paracetamol and nefopam, complemented with patient-controlled-released morphine infusion (continuous infusion at an initial dose of 2 mg/hour with repeated pulses) after an initial titration (0.1 mg/kg every 5 minutes until pain relief was achieved); 4) blood transfusion and/or phlebotomy (according to hemoglobin level). The decision to transfuse was made by SCD Center medical staff (which was unaware of the treatment arm), according to the following predefined indications: respiratory distress with a respiratory rate >30/minute, bilateral involvement of four lung quadrants on chest radiograph, multiple organ failure, worsening or lack of improvement in pain or dyspnea despite optimal supportive treatment for three days, severe anemia with a hemoglobin level < 6g/dL; 5) antibiotic therapy (amoxicillin + spiramycin or telithromycin) in patients with a body temperature > 38°C and/or PaO2/FiO2 ≤ 300 mmHg. In patients with persistent respiratory distress despite red-blood-cell transfusion, noninvasive ventilation was initiated and orotracheal intubation was performed if noninvasive ventilation failed according to predefined criteria [3]. Mechanical ventilation was considered as treatment failure, and inhaled treatment was interrupted.
Safety monitoring
Because a primary toxicity of iNO is methemoglobinemia, the venous methemoglobin level was monitored at baseline and every 2 hours for the first 8 hours, then every 12 hours for the duration of the study. Bedside personnel and site investigators had no access to methemoglobin levels, which were reported by designated personnel through a web system at each site, who only notified site investigators if a dose change was indicated. A methemoglobin level of 5% or greater prompted a 50% decrease of the inhaled treatment dose and a second check one hour later. If any value was greater than 7.5%, inhaled therapy was discontinued. Other stopping rules included (1) clinically significant hypotension (systolic blood pressure less than 60 mmHg for longer than 20 minutes); (2) sepsis or septic shock; (3) sustained pulse oxygen saturation below 85% for longer than 20 minutes, and/ or need for ventilatory support (invasive or non-invasive), (4) investigator, treating physician, or participant opinion that discontinuation of inhalation therapy was in the patient’s best interest; (5) any serious adverse event believed related to the investigational therapy. Participants who were discontinued from therapy remained in the study and continued with data collection, unless consent to do so was withdrawn. Serious adverse events were recorded during study gas inhalation and defined as any event that at any dose required modification of care or resulted in disability or death. The DSMB reviewed the safety data after 25 and 50 patient inclusions. Pre-defined criteria for stopping the study were 1) a difference of more than 4 deaths in one group, 2) interruption of inhaled treatment in more than 10 patients within one group. An interim analysis of efficacy was not planned.
References:
1. Lee K, Gane P, Roudot-Thoraval F, et al. (2001) The nonexpression of CD36 on reticulocytes and mature red blood cells does not modify the clinical course of patients with sickle cell anemia. Blood 98:966–971.
2. Hebbel RP, Boogaerts MA, Eaton JW, Steinberg MH (1980) Erythrocyte adherence to endothelium in sickle-cell anemia. A possible determinant of disease severity. N Engl J Med 302:992–995. doi: 10.1056/NEJM198005013021803
3. Antonelli M, Conti G, Rocco M, et al. (1998) A comparison of noninvasive positive-pressure ventilation and conventional mechanical ventilation in patients with acute respiratory failure. N Engl J Med 339:429–435. doi: 10.1056/NEJM199808133390703
eTable 1: Demographics and Baseline Characteristics of Hypoxemic Patients by Treatment
iNO(n=21) / Placebo
(n=25) / P
Characteristics / Median [IQR]b / Median [IQR]b / valuea
Age, y / 28 [24-32] / 29 [23-31] / 0.69
Male sex, No. (%) / 14 (67) / 14 (58) / 0.56
Sickle cell genotype, SS, SC/Sß+ (%) / 17(81)/4(19) / 20(80)/5(20) / >0.99
Hemoglobin, g/dL / 8.9 [8.3-9.9] / 8.7 [8-9.5] / 0.65
SS / 8.7 [8-9.8] / 8.7 [8-9.3]
SC/Sß+ / 11 [10.5-12] / 11.5 [11.2-12]
Reticulocytes, % / 8.7 [5.5-11.2] / 7.9 [3.6-10.8] / 0.62
Hb F, % / 4.7 [1.8-10.8] / 4.6 [3-7] / 0.7
Lactate dehydrogenase, U/L / 413 [346-501] / 403 [306-492] / 0.76
Total bilirubin, mg/dL / 34 [25.5-70.5] / 42 [24-60] / 0.91
Past medical history
Hebbel score / 10 [10-11] / 10 [9-11] / 0.99
Left heart disease, No. (%) / 2 (9.5) / 1 (4.0) / 0.59
Pulmonary hypertension, No. (%) / 1 (4.8) / 0 (0.0) / >0.99
Thrombo-embolic disease, No. (%) / 2 (9.5) / 2 (8.0) / >0.99
Chronic hydroxyurea treatment, No. (%) / 5 (24.0) / 6 (24.0) / 0.93
Chronic transfusion therapy, No. (%) / 0 (0.0) / 0 (0.0) / >0.99
Abbreviations: IQR, interquartile range; HbF, fetalhemoglobin
a between group comparison using χ2 or Wilcoxon 2-sample test
b except where otherwise noted
Hebbel score= see reference 16,17
eTable 2: Characteristics at Inclusion of Hypoxemic Patients by Treatment
iNO(n=21) / Placebo
(n=25)
Characteristics / Median [IQR]b / Median [IQR]b / P
valuea
Symptoms
Temperature °C / 37.5 [37.0-38.4] / 37.6 [37.4-38.2] / 0.66
Chest Pain, No (%) / 21 (100) / 20 (80) / 0.05
Extrathoracic Pain, No (%) / 13 (62) / 12 (48) / 0.35
Pain VAS / 5 [4-6] / 5 [3-6] / 1
Heart rate, beats/min / 101 [87-111] / 95 [86-108]
Respiratory rate, breaths/min / 29 [25-34] / 26 [23-34] / 0.58
SpO2, % / 96 [95-98] / 97 [95-99] / 0.60
Chest X-ray
Bilateral parenchymal involvement, No(%) / 18 (86) / 21 (84) / 1
Pleural involvement, No (%) / 9(43) / 10 (52) / 0.58
Blood gases
PaO2, mmHg / 83 [74-94] / 82 [75-95] / 0.75
FiO2, % / 36 [32-40] / 38 [32-47] / 0.77
PaO2/FiO2 ratio / 230 [208-257] / 226 [203-278] / 0.54
PaCO2, mmHg / 46 [42-47] / 45 [42-49] / 0.99
SaO2, % / 96 [94-97] / 96 [95-97] / 0.76
pH / 7.39 [7.38-7.42] / 7.40 [7.38-7.43] / 0.47
Laboratory values
White cell count, x 103/µL / 18.5 [16-21] / 19.1 [11.1-26.7] / 0.55
Platelet count, x 103/µL / 221[189-311] / 278 [196-389] / 0.16
Total hemoglobin, g/dL / 9.1 [8.5-9.8] / 8.9 [7.5-10.3] / 0.65
SS g/dL / 8.9 [8.6-9.9] / 8.4 [7.5-9.5] / 0.37
SC/S-ßthal g/dL / 9.6 [8.3-11] / 10.7 [89.1-11.5] / 0.84
Reticulocyte count, , x 103/µL / 174.5 [124.5-199.5] / 209 [153-293] / 0.13
Alanine aminotransferase, U/L / 43 [23-79] / 32 [21-46] / 0.1
Aspartate aminotransferase, U/L / 44 [31-70] / 45 [32-60] / 0.47
Lactate dehydrogenase, U/L / 507 [379-804] / 431 [339-770] / 0.62
Total bilirubin, mg/dL / 63 [45-105] / 49 [37-79] / 0.95
C-reactive protein, mg/L / 150 [123-247] / 207 [172-227] / 0.22
Blood ureanitrogen, mmol/L / 3 [2-4] / 3 [2.4] / 0.66
Transfusion before inclusion, No (%) / 14 (67) / 13 (54)
Phlebotomy before inclusion, No (%) / 9 (42.9) / 9 (37.5)
Abbreviations: IQR, interquartile range; VAS, visual analogic scale;
a between group comparison using χ2 or Wilcoxon 2-sample test
b except where otherwise noted
eTable 3 Effects of Inhaled Nitric Oxide Gas on primary and secondary outcomes in hypoxemic patients
Covariate / iNO(n=21)
Median [IQR]b / Placebo
(n=25)
Median [IQR]b / P
valuea
Primary outcome
Composite score of failure at D3, No. (%) / 7 (33.3) / 18 (72.0) / 0.01
Secondary outcome
Decrease of PaO2/FiO2 ratio ≥ 15 mmHg between day 3
and day 1, No. (%) / 2 (9.5) / 7 (28.0) / 0.15
Transfusion and/or phlebotomy between day 1 and day 3,
N° (%) / 7 (33.3) / 16 (64.0) / 0.04
Death / 0 / 0
Invasive mechanical Ventilation / 0 (0.0) / 1 (4.2)
PaO2/FiO2 < 300 mmHg at day 3 No. (%) / 10 (55.6) / 14 (58.3) / 0.86
Opioids
Daily dose of opioids between day 1 and day 3, mg / 84 [45-187] / 120 [66-241] / 0.30
Cumulative dose of opioids, mg / 191 [106-373] / 244 [167-339] / 0.72
Transfusion and phlebotomy
Transfusion D1-D3, No. (%) / 7 (33.3) / 13 (52.0) / 0.46
Phlebotomy D1 -D3, No. (%) / 3 (14.3) / 9 (36.0) / 0.29
Transfusion during the hospital stay, No. (%) / 18 (86.0) / 23 (92.0) / 0.65
Phlebotomy during the hospital stay, No. (%) / 13 (62.0) / 15 (60.0) / 0.89
Total number of transfused red blood cell in all
transfused patients, units / 3 [2.4] / 3.5 [2.4] / 0.45
Total volume of exsanguinated blood in the
patients with partial EST, ml / 550 [250-750] / 950 [500-1150] / 0.09
Length of stays, days
ICU / 5 |4- 6] / 5 |4- 6] / 0.33
Hospital / 9 [8-11] / 11 [9-13] / 0.08
a between group comparison using χ2 or Wilcoxon 2-sample test
b except where otherwise noted
eTable 4: Safety outcome
OutcomeMeasures / iNO(n=50) / Placebo
(n=50) / P
value a
Systolic blood pressure between day 1 and day 3, mmHg
Median, [IQR] (lowest) / 124 [113-139] (90) / 130 [120-139] (95) / 0.21
Oxygen saturation between day 1 and day 3,%
Median, [IQR] (lowest) / 98 [96-100] (93) / 98 [97-99] (92) / 0.75
Nitrogen dioxide delivered, ppm
Median, [IQR] (highest)
At 0 h / 0.7 [0.5-1.2] (4) / 0.1 [0.0-0.1] (0.9) / 0.03
At 24 h / 0.5 [0.4-0.7] (4) / 0.1 [0.0-0.2] (0.9) / 0.16
At 48 h / 0.5 [0.3-0.6] (3) / 0.1 [0.0-0.2] (0.4) / <0.01
At 72 h / 0.3 [0.2-0.5] (3) / 0.1 [0.1-0.2] (0.3) / 0.13
Abbreviations: iNO, inhaled nitric oxide; IQR, interquartile range;a between group comparison using χ2 or Wilcoxon 2-sample test
1