ABSTRACT
STUDY OBJECTIVE: Elevated pulmonary vascular resistance is a risk factor in heart transplantation and reversibility of high pulmonary vascular resistance is evaluated preoperatively in potential recipients using i.v. vasodilators or inhaled nitric oxide. Prostacyclin is a potent vasodilator, which when inhaled, has selective pulmonary vasodilatory properties. The aim of this study was to compare the central hemodynamic effects of inhaled prostacyclin with those of inhaled nitric oxide in heart transplant candidates. DESIGN: A pharmacodynamic comparative study. SETTING: Cardiothoracic ICU or laboratory for diagnostic heart catheterization at a university hospital. PATIENTS: Ten heart transplant candidates with elevated pulmonary vascular resistance (>200 dynes x s x cm(-5) and/or a transpulmonary pressure gradient > 10 mm Hg) were included in the study. INTERVENTIONS: Nitric oxide (40 ppm) and aerosolized prostacyclin (10 microg/mL) were administered by inhalation in two subsequent 10-min periods. Hemodynamic measurements preceded and followed inhalation of each agent. MEASUREMENTS AND RESULTS: Both inhaled nitric oxide and inhaled prostacyclin reduced mean pulmonary artery pressure (-7% vs -7%), pulmonary vascular resistance (-43% vs -49%), and the transpulmonary gradient (-44% vs -38%). With inhaled prostacyclin, an 11% increase in cardiac output was observed. Other hemodynamic variables, including the systemic BP, remained unaffected by each of the agents. CONCLUSIONS: Inhaled prostacyclin induces a selective pulmonary vasodilation that is comparable to the effect of inhaled nitric oxide. Major advantages with inhaled prostacyclin are its lack of toxic reactions and easy administration as compared with the potentially toxic nitric oxide requiring more complicated delivery systems.
Subject(s)
Epoprostenol/administration & dosage , Heart Transplantation , Nitric Oxide/administration & dosage , Pulmonary Artery/physiopathology , Vascular Resistance , Vasodilator Agents/administration & dosage , Administration, Inhalation , Adult , Aerosols , Epoprostenol/pharmacology , Female , Hemodynamics/drug effects , Humans , Hypertension, Pulmonary/diagnosis , Hypertension, Pulmonary/drug therapy , Male , Middle Aged , Nitric Oxide/pharmacology , Patient Selection , Preoperative Care , Pulmonary Artery/drug effects , Pulmonary Circulation , Vascular Resistance/drug effects , Vasodilation/drug effects , Vasodilator Agents/pharmacologyABSTRACT
BACKGROUND: Following an episode of acute respiratory distress syndrome (ARDS), some degree of measurable pulmonary impairment may be anticipated. ARDS is thought to be the more severe form of acute lung injury (ALI) and a recently proposed addition to conventional therapy in ALI/ARDS is inhaled nitric oxide (INO). We carried out a non-randomised follow-up study with pulmonary function tests on survivors of severe ALI/ARDS treated with INO. METHODS: Sixteen previously healthy pulmonary patients, survivors of severe ALI/ARDS, were evaluated with pulmonary function tests >8 months after the acute event. The tests included static and dynamic spirometry, diffusion capacity for carbon monoxide (DLCO), blood gas analysis and evaluation of a chest radiograph. RESULTS: The most common abnormality seen was a low DLCO in 69% of the patients. Abnormally low values were seen in forced vital capacity in 31%, in forced expiratory volume in 1 s in 13%, and in residual volume and total lung capacity in 6%. Blood gas data were within normal limits in 15/16 patients. All chest radiographs showed resolution of the interstitial and alveolar changes present during the acute event. CONCLUSION: In this non-randomised follow-up study we conclude that a degree of measurable pulmonary impairment after INO treatment in severe ALI/ARDS was common, but did not differ markedly from other published studies on pulmonary function in similar patient material. No late unexpected major abnormalities due to the inhaled nitric oxide treatment could be identified in these survivors.
Subject(s)
Lung/physiopathology , Nitric Oxide/administration & dosage , Respiratory Distress Syndrome/drug therapy , Administration, Inhalation , Adult , Aged , Female , Humans , Male , Middle Aged , Oxygen/blood , Radiography, Thoracic , Respiratory Distress Syndrome/physiopathologyABSTRACT
BACKGROUND: Patients with severe acute lung injury (ALI) have been treated compassionately on doctors' initiative with inhaled nitric oxide (INO) in Sweden and Norway since 1991. In 1994 the previously used technical grade nitric oxide was replaced by medical grade nitric oxide. METHODS: We have carried out a retrospective data collection on all identified adult patients treated with INO for >4 h during the period 1991-1994 focusing on safety aspects and patient outcome. We used the following exclusion criteria (1) Age <18 years, (2) Simultaneous treatment with extracorporeal removal of CO2 (3) NO inhalation period <4 h, (4) Incomplete or missing patient charts, (5) Use of INO in order to treat pulmonary hypertension following cardiac surgery, with little or no acute lung injury. RESULTS: Inclusion criteria were met by 56 out of 73 identified patients. Mean age was 48+/-19 years and the median duration of INO treatment was 102 h. PaO2/FIO2 ratio at start of treatment was 85 +/- 33 mm Hg with a lung injury score (LIS) of 3.2+/-0.8. The aetiology of the lung injury was pneumonia (n= 27), sepsis (n=12) and trauma (n=8). Survival to hospital discharge was 41% and survival after 180 d was 38%. Three serious adverse events were identified, two from technical failures of the INO delivery device and one withdrawal reaction necessitating slow weaning from INO. No methaemoglobin values >5% were reported during treatment. CONCLUSION: The overall mortality did not differ dramatically from historical controls with high mortality. Only a randomised study may determine whether INO as an adjunct to treatment alters the outcome in severe ALI. One cannot at present advocate the routine use of INO in patients with ALI outside such studies.
