Nitric oxide ventilation
This writing is intended to briefly introduce ARDS patients, their families, and significant others, with the properties of nitric oxide and the clinical implications associated with the use of this gas. Nitric oxide (NO) should not be confused with nitrous oxide (N20), the mild anesthetic often used by dental professionals that is more commonly known as "laughing gas." As a matter of fact, nitric oxide was known as a common environmental pollutant and contaminant during the manufacturing process of nitrous oxide. NO is normally manufactured from the reaction of sulfur dioxide with nitric acids. Nitric oxide is a component of smog that can be measured in urban area air at 10 to 100 parts per billion (ppb), is naturally produced in the body in the upper and lower airway at 100 to 1000 ppb, and is present in cigarette smoke at 400 to 1000 parts per million (ppm). Clinical research found that the concentration of exhaled NO is increased during exercise and in patient's with asthma.
Inhaled NO is a relatively new United States Food and Drug Administration (FDA) investigational drug and numerous facilities are involved in clinical trials utilizing this gas. Until approved by the FDA, its use is limited to those facilities that have gone through the application process for drug evaluation and research and have been granted permission (known asan Investigational New Drug [IND] number) to conduct such studies utilizing NO. In addition, an informed consent procedure must be obtained from each patient or legal representative prior to the administration of NO.
Physiology of ARDS
Those of you familiar with this newsletter may have as much information on ARDS as many physicians and researchers. Nevertheless, a limited review of the pulmonary disease ARDS is necessary to gain an understanding of the way in which NO affects this pulmonary ailment.
Patients with ARDS, whether precipitated by inhalation of vomited stomach contents (aspiration), injury, pneumonia, inhalation of toxic substances, or a severe infection somewhere in the body (sepsis), usually all have high blood pressure in the vessels leading to and around the lungs (pulmonary hypertension.) Also, under normal conditions, if the tiny air sacs in the lung (alveoli) do not receive enough air or are collapsed (atelectasis), the blood vessels supplying these alveoli will constrict (become smaller or narrower). In ARDS however, these collapsed or underventilated alveoli continue to receive full blood supply from the surrounding blood vessels (capillaries). Since these collapsed or underventilated alveoli are not receiving oxygen, they are not capable of providing oxygen to the blood stream. The net effect may be a severe reduction in oxygen levels in the blood stream.
Two studies say yes to no therapy for preemies; inhaled nitric oxide is demonstrated to prevent brain injury and chronic lung disease in VLBW ... An article from: Pediatric News
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