Pulse Oximetry and the Neonate.
نویسنده
چکیده
Evaluation of the newborn who has cyanosis requires prompt and logical assessment. Although entities such as polycythemia and methemoglobinemia must be considered, the diagnoses that must be addressed most urgently are primary respiratory disease, congenital heart disease (CHD), and persistent pulmonary hypertension of the newborn (PPHN). These categories of disease are not mutually exclusive, as in the case of meconium aspiration with PPHN, but their distinct pathophysiologic mechanisms account for different results in diagnostic testing. The essence of PPHN lies in the pathologic failure of pulmonary artery pressure to decline postnatally. Although pulmonary artery pressure varies directly with pulmonary vascular resistance (PVR), pulmonary blood flow, and pulmonary capillary wedge pressure, the first of these plays the most prominent role in PPHN. Persistently elevated PVR may result from the perinatal failure to elaborate nitric oxide and/or prostaglandin I2 in addition to increased production of phosphodiesterase-3 or -5, endothelin-1, reactive oxygen species, and rhokinase. The net effect is right ventricular dysfunction as well as right-to-left shunting across fetal channels (ie, the patent foramen ovale and ductus arteriosus), which results in decreased pulmonary blood flow. The affected infant develops ventilation/perfusion mismatch, hypoxemia, and acidosis that can lead to left ventricular dysfunction, decreased output, and shock.When differentiating PPHN from cyanotic CHD, the clinician must pay careful attention to patient history; familial occurrence of CHD; and risk factors for PPHN, including sepsis, perinatal asphyxia, intrauterine growth restriction, andmaternal medications (eg, selective serotonin reuptake inhibitors, indomethacin) (Table 1). On physical examination, the clinician should auscultate for heart murmurs, compare upper and lower extremity pulses, assess for hypotension associated with the patient’s cyanosis, and examine the cardiac silhouette on chest radiography. For many years, the “hyperoxia test” was used to distinguish the 3 major causes of cyanosis. Arterial blood gases were obtained before and after infants were placed in 100%oxygen. If an initially low PaO2 rose to equal to or greater than 150 mm Hg following hyperoxia, the likely diagnosis was respiratory disease. Nonresponders with either cyanotic CHD or PPHN were subsequently hyperventilated. Decreased PaCO2 and alkalosis would dilate the pulmonary vasculature in PPHN, resulting in increased PaO2, which would not be the case in cyanotic CHD. Recently, echocardiography with color Doppler directional flow has supplanted the hyperventilation phase of the hyperoxia test. However, use of blood gases is limited by the technical difficulty in obtaining them by arterial puncture; a falsely low PaO2 may result when an infant’s crying leads to increased right-to-left shunting. Also, changes in clinical status may not be evident during the interval between the 2 samplings. Consequently, the routine introduction of pulse oximetry into the care of neonates has had a significant impact. AUTHOR DISCLOSURE Dr Roth has disclosed no financial relationships relevant to this article. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.
منابع مشابه
Pulse Oximetry Screening to Detect Cyanotic Congenital Heart Disease in Sick Neonates in a Neonatal Intensive Care Unit.
OBJECTIVE To evaluate pulse oximetry for detection of congenital cyanotic heart disease in sick neonates using echocardiography as gold standard. METHODS Pulse oximetry readings were taken at admission from 950 neonates from right upper limb and either foot with infant breathing room air. Pulse oximetry was considered abnormal if oxygen saturation at room air measured <90% or difference betwe...
متن کاملEvaluation and Improvement of Knowledge of Medical staff on Pulse Oximetry in Educational Hospitals
Background: Pulse Oximeter monitoring has become so common over previous decades that in some health care units, blood oxygen level is now considered as the fifth vital sign. However, it seems there is still some lack of knowledge and/or experience among medical staff operating pulse oximeter and interpreting its results. The aim of this study was to investigate and compare the knowledge on Pul...
متن کاملEvaluation and Improvement of Knowledge of Medical staff on Pulse Oximetry in Educational Hospitals
Background: Pulse Oximeter monitoring has become so common over previous decades that in some health care units, blood oxygen level is now considered as the fifth vital sign. However, it seems there is still some lack of knowledge and/or experience among medical staff operating pulse oximeter and interpreting its results. The aim of this study was to investigate and compare the knowledge on Pul...
متن کاملEvaluation of Pulse Oximetry in the Early Detection of Congenital Heart Diseases in Newborns
Background: Congenital heart diseases, which are asymptomatic at birth, are the most important causes of infant mortality. This study aimed to evaluate the role of pulse oximetry in the early detection of congenital heart diseases among newborns.Methods: In this cross-sectional descriptive study, 1230 newborns who were born in university hospitals in an urban area of Iran were placed unde...
متن کاملComparative study of pulse oximetry, physical examination and echocardiography results in the diagnosis of congenital heart defects in neonates in the first 24 hours of life
Introduction: Congenital heart disease is the most common congenital anomaly. About 50% of Neonates with congenital heart disease are asymptomatic in the first few days of life and are not diagnosed on initial examination. Pulse oximetry is a non-invasive method that can show the percentage of oxygen saturation in the blood and congenital heart disease. Methods: This was a descriptive cross-se...
متن کاملCan we Replace Arterial Blood Gas Analysis by Pulse Oximetry in Neonates with Respiratory Distress Syndrome, who are Treated According to INSURE Protocol?
Neonates with respiratory distress syndrome (RDS), who are treated according to INSURE protocol; require arterial blood gas (ABG) analysis to decide on appropriate management. We conducted this study to investigate the validity of pulse oximetry instead of frequent ABG analysis in the evaluation of these patients. From a total of 193 blood samples obtained from 30 neonates <1500 grams with RDS,...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Pediatrics in review
دوره 37 9 شماره
صفحات -
تاریخ انتشار 2016