Neonatal-Pediatric Respiratory Care PDF

‫كليـــــــة بلقيـــــــس للـــعــــلوم الطـــــبية‬ Belqees Yemen Collage for Medical Sciences Neonatal-Pediatric Respiratory Care Apnea & Thermal Regulation 3ed year respiratory therapist student Dr:MOHAMMED-SENAN BS, RCP, FNIV,MsRC...

‫كليـــــــة بلقيـــــــس للـــعــــلوم الطـــــبية‬ Belqees Yemen Collage for Medical Sciences Neonatal-Pediatric Respiratory Care Apnea & Thermal Regulation 3ed year respiratory therapist student Dr:MOHAMMED-SENAN BS, RCP, FNIV,MsRC DrMohammmed Senana 1 Introduction NEONATAL APNEA DEFINITIONS Apnea is an unexplained episode of cessation of breathing for 20 seconds or longer, or a shorter respiratory pause associated with bradycardia, cyanosis, pallor, or hypotonia. 1- Apnea of prematurity (AOP) is defined as sudden cessation of breathing that lasts for at least 20 seconds or is accompanied by bradycardia or cyanosis in an infant younger than 37 weeks postmenstrual age. 2-Apnea of infancy (AOI) generally refers to infants with a postmenstrual age of 37 weeks or more at the onset of apnea. DrMohammmed Senana 2 Introduction 3- Periodic breathing (PB) is defined as bursts of respiratory activity of 20 seconds or less separated by central apneic pauses lasting from 3 to 10 seconds. Periodic breathing is present in almost all preterm babies and can also be seen in term babies. The cause of periodic breathing remains obscure, although the finding that it is absent until 48 hours of age suggests that inactivity of peripheral chemoreceptors at this time might play a role. 4- Brief resolved unexplained event (BRUE) is defined as a sudden, brief, resolved episode characterized by some combination of cyanosis or pallor; absent, decreased, or irregular breathing; marked change in muscle tone (usually marked limpness); and/or an altered level of responsiveness. DrMohammmed Senana 3 Introduction BRUE is a recent term intended to characterize many events previously described under the broader term acute life-threatening event (ALTE). 5. Sudden Unidentified Infant Death Syndrome (SUIDS) is defined as the sudden death of an infant younger than 1 year of age that remains unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene, and review of the clinical history. DrMohammmed Senana 4 Apnea CLASSIFICATION Apnea traditionally is classified into three categories based on the presence or absence of upper airway obstruction: 1. Central apnea is caused by the lack of a neurologic drive to breathe, resulting in cessation of inspiratory efforts with no evidence of obstruction. 2. Obstructive apnea occurs when an infant tries to breathe against an obstructed upper airway, resulting in chest wall motion without airflow through the apneic episode. 3. Mixed apnea consists of obstructed respiratory efforts, usually after central pauses. DrMohammmed Senana 5  Apnea INCIDENCE Apneic spells occur frequently in premature infants. The incidence of apnea increases with decreasing gestational age. More than 50% of infants weighing less than 1500 g and 90% of infants weighing less than 1000 g will have apnea. About half of moderately preterm infants, between 33 and 35 weeks gestational age, will have apnea. Even some term infants exhibit apnea, though it is rare. In these cases, other causes such as infection, seizures, intracranial hemorrhage, birth asphyxia, upper airway obstruction, or depression from medication need to be ruled out. Apneic spells generally begin at 1 or 2 days after birth; if they do not occur during the first 7 days, they are unlikely to occur later. If an infant has a new onset of apneic spells after 1 week of age, other causes must be ruled out. Apneic spells persist for variable periods postnatally and usually cease by 37 weeks postmenstrual age but may persist beyond term equivalent, up to approximately 43 weeks postmenstrual age DrMohammmed Senana 6 Apnea ETIOLOGY AND PATHOPHYSIOLOGY Developmental immaturity of the central respiratory drive is a key factor in the pathogenesis of AOP. Premature infants are believed to be susceptible to apneic episodes also because of immature afferent input from chemoreceptors and lung and airway receptors, with diminished responses to both hypercapnia and hypoxia. Sleep-related response may be a factor in apnea and periodic breathing. Nearly 80% of a preterm infant’s time is spent sleeping, with approximately 90% of a sleep cycle spent in rapid eye movement (REM) sleep, and the infant often has difficulty making the transition between the sleeping and waking states. Apneic spells occur more frequently in REM states. DrMohammmed Senana 7 Apnea ETIOLOGY AND PATHOPHYSIOLOGY Weakness of both the muscles of respiration and the muscles that maintain airway patency plays an important role in contributing to airway obstruction. Nasal obstruction in premature infants who are obligate nasal breathers also may contribute to apneic spells. Although physiologic immaturity is the most common cause of apnea, secondary causes of apnea must be considered in all infants, especially those presenting with apnea after 1 week of age and increased frequency of spells, or term infants with spells. DrMohammmed Senana 8 Apnea ETIOLOGY AND PATHOPHYSIOLOGY Secondary causes include the following: 1. Temperature instability: Hypothermia and hyperthermia 2. Neurologic: Birth trauma, intracranial infection, intracranial hemorrhage, perinatal asphyxia, seizures, medications including anesthetics 3. Pulmonary: RDS, pneumonia, pulmonary hemorrhage, obstructive airway lesion, pneumothorax, BPD 4. Cardiac: Congenital cyanotic heart disease, hypotension/hypertension, congestive heart failure, PDA 5. Hematologic: Anemia, polycythemia 6. Infectious: Sepsis, Necrotizing enterocolitis (NEC) DrMohammmed Senana 9 Apnea ETIOLOGY AND PATHOPHYSIOLOGY Secondary causes include the following: 7. Metabolic: Hypoglycemia, hypocalcemia, hyponatremia, hypernatremia 8. Inborn errors of metabolism 9. Gastrointestinal: Gastroesophageal reflux (GER), esophagitis Both GER and apnea are common in preterm infants, and GER is commonly cited as a cause of apnea. However, studies have not demonstrated a consistent temporal relationship between GER and apneic, bradycardic, or desaturation spells. Additionally, during an apneic episode, loss of respiratory neural output may be accompanied by a decrease in lower esophageal tone, and GER may result from the apneic spell itself. DrMohammmed Senana 10 Apnea CLINICAL PRESENTATION Apnea of prematurity typically first presents 2 to 3 days after birth. Apnea before 24 hours of life may be associated with infant or maternal pathologic conditions (e.g., neonatal sepsis, hypoglycemia, intracranial hemorrhage, maternal antepartum magnesium treatment, or maternal exposure to narcotics). When apnea occurs in a preterm infant after the first 24 hours of life and is not associated with any other pathologic condition, it may be classified as AOP. Apnea may also occur after weaning from prolonged ventilatory support and may be associated with intermittent hypoxia secondary to hypoventilation or atelectasis. In infants with BPD, decreased pulmonary reserves may contribute to frequent occurrence of spells. DrMohammmed Senana 11 Apnea Diagnosis Apnea is generally diagnosed with continuous cardiorespiratory monitoring. If significant apnea is detecte 1. Monitoring of infants at risk: Close monitoring to evaluate possible causes of apnea should focus on respiratory rate and pattern, heart rate, circumstances preceding the apneic episode, associated bradycardia, skin color, muscle tone, and termination of the episode (whether spontaneous, with stimulation, or with resuscitation). DrMohammmed Senana 12 Apnea Diagnosis 2. Detailed history and physical examination: After stabilization, the infant should be evaluated for a possible underlying cause. The history should be reviewed for onset of apnea and possible causes of secondary apnea, including perinatal asphyxia, maternal drugs, features of neonatal sepsis, and feeding intolerance. The infant should be examined for temperature instability, hypotension, jaundice, pallor, cardiac murmur, and poor perfusion. 3. Evaluation: The diagnostic evaluation is directed by the clinical presentation and the infant’s associated findings. DrMohammmed Senana 13 Apnea Diagnosis 3. Evaluation: When there is concern for a secondary cause, the evaluation includes a sepsis screen, chest radiograph, and glucose and serum electrolyte measurements. Screening for neurologic abnormalities, such as intracranial hemorrhage, hydrocephalus, or seizures, may be warranted. An abdominal radiograph should be obtained if NEC is suspected. Other evaluation may be considered in specific cases. An echocardiogram and a cardiology consultation are necessary if the history or physical examination suggests cardiac disease. DrMohammmed Senana 14 Apnea Diagnosis 3. Evaluation: An electrocardiogram (ECG) is useful when severe unexplained tachycardia or bradycardia exists. Testing of serum ammonia levels as well as urine and serum amino acids and organic acids is indicated if a metabolic disorder is suspected. An airway evaluation for upper airway abnormalities or obstruction can be considered. In infants with persistent apnea, impedance pneumography (“pneumograms”) or sleep studies can further classify apnea as obstructive, central, or mixed and can provide information about association with GER, with intraesophageal pH monitoring DrMohammmed Senana 15 Apnea TREATMENT 1- General Measures If an identifiable cause of apnea is determined, it should be treated accordingly. Care should be taken to avoid reflexes that may trigger apnea. Suctioning of the pharynx should be done carefully, and oral feedings should be undertaken with caution. Positions of extreme flexion or extension of the neck should be avoided to reduce the likelihood of airway obstruction. Gentle tactile stimulation is often adequate therapy for mild and intermittent episodes. Avoiding swings in environmental temperature may prevent apnea. DrMohammmed Senana 16 Apnea TREATMENT 2- Xanthine Derivatives (Caffeine and Theophylline) Proposed mechanisms for xanthine derivatives include stimulation of skeletal and diaphragmatic muscle contraction, increase in the respiratory center’s sensitivity to CO2, and stimulation of the central respiratory drive. Caffeine appears to be a safer drug, can be given less frequently than theophylline, and is more effective in treating apnea. In the Caffeine for Apnea of Prematurity (CAP) trial, early caffeine therapy in infants weighing less than 1250 g reduced the rate of bronchopulmonary dysplasia and improved neurodevelopmental outcome at 18 to 21 months of age, though the difference in neurologic outcome did not persist at 5- year followup. DrMohammmed Senana 17 Apnea TREATMENT 2- Xanthine Derivatives (Caffeine and Theophylline) Side effects include decreased initial weight gain, increased feeding intolerance, and increased heart rates. Caffeine is typically started with a loading dose of caffeine citrate 20 mg/kg, followed by maintenance doses of 5 to 10 mg/kg, though higher doses may be used. Many centers empirically begin caffeine in all infants weighing less than 1250 g shortly after birth and premature infants more than 1250 g who have symptomatic apnea. It is continued until 34 to 36 weeks postmenstrual age, though it may be required longer in extremely premature infants if spells continue beyond this age. Because caffeine has a half-life of about 3 days, its effect may continue for approximately 1 week after discontinuation. DrMohammmed Senana 18 Apnea TREATMENT 3- CPAP and Nasal Intermittent Positive Pressure Ventilation CPAP at moderate levels (5-7 cm H2O) can reduce the number of mixed and obstructive apneic spells. It is especially useful in infants younger than 32 to 34 weeks gestational age and those with residual lung disease. It remains controversial whether NIPPV is a useful augmentation to CPAP to prevent spells. 4- Mechanical Ventilation Some infants continue to have apneic spells despite pharmacotherapy. If the apnea is severe and is associated with hypoxia or significant bradycardia, intubation and mechanical ventilation may be indicated. DrMohammmed Senana 19 Apnea TREATMENT 5- Blood Transfusions Apneas occur with increased frequency at lower hemoglobin levels, and there seems to be a beneficial effect from blood transfusion in the setting of anemia in reducing the frequency of apneic events. 6- Discharge Planning and Follow-up A major issue in the management of infants with apnea is deciding when to stop administration of methylxanthines and whether the infant needs to be discharged on methylxanthines, a home monitor, or both. The answers to these questions are still under debate. Most neonatologists allow a 5-to-7-day apnea-free period after a subtherapeutic level of methylxanthine therapy before sending a premature infant home without a monitor. DrMohammmed Senana 20 Apnea TREATMENT 6- Discharge Planning and Follow-up Home monitoring is not routinely recommended for infants with a history of apnea of prematurity.151 The theoretical purpose of home monitoring is prevention of SUIDS; however, the CHIME study, which analyzed events among a large set of healthy term infants and preterm infants discharged on home monitoring, suggested that even severe cardiorespiratory events were unlikely to be precursors to SIDS.163 Thus home monitoring is reserved for infants on methylxanthine therapy at the time of discharge because of persistent cardiorespiratory events or infants discharged on oxygen (oximetry only). If home monitoring is arranged for persistent cardiorespiratory events, it can usually be discontinued by 44 weeks postmenstrual age. Extensive psychosocial support should be provided to parents taking home an infant with a home monitor, and parents should be skilled in the use of the monitor and cardiopulmonary resuscitation. DrMohammmed Senana 21 Apnea COMPLICATIONS AND PROGNOSIS AOP AOP does not alter an infant’s prognosis unless it is severe, recurrent, or refractory to therapy. Although premature infants are at increased risk of SIDS, a history of apnea of prematurity does not increase this risk. Therefore all parents of premature infants should be counseled on risk- reduction strategies, including promoting a supine sleeping position on a firm surface, avoiding co-sleeping, avoiding overheating, and decreasing smoking in the home.. DrMohammmed Senana 22 Neonatal Thermoregulation DrMohammmed Senana 23 Introduction Maintaining a neutral thermal environment is one of the key physiologic challenges that a newborn must face after delivery. Thermal care is central to reducing morbidity and mortality in newborns. Thermoregulation is the ability to balance heat production and heat loss in order to maintain body temperature within a certain normal range. The average “normal” axillary temperature is considered to be 37°C. The Canadian Paediatric Society recommends taking temperature via the axillary route to screen low risk newborns from birth to 2 years.There is a lack of evidence on what constitutes the “normal” temperature range for a newborn. The American Academy of Pediatrics (AAP) and the American College of Obstetricians and Gynecologists (ACOG) and (WHO) define normal axillary temperatures to be between 36.5°C and 37.5°C. The Acute Care of at-Risk Newborns Neonatal Society (ACoRN) define normal axillary temperature to be between 36.3°C-37.2°C DrMohammmed Senana 24 Neonatal Thermoregulation Definition: the balance between the heat production and heat lost from the body, measured in heat unit called degree. Fahrenheit scale uses 32 F as the water freeze point and 212 F as boil point. centigrade scale uses 0 as the water freeze and 100 C as boil point. Normal body temperature: 36.4 – 37.4 C DrMohammmed Senana 25 Neonatal Thermoregulation Two type of body temperature: Core temperature: is the temperature of deep tissue of the body such as thorax, abdominal cavity. it relatively constant. Surface temperature: is the temperature of skin, subcutaneous tissue rise and fall in response to environment. DrMohammmed Senana 26 Neonatal Thermoregulation Ways of heat loss: Radiation: is transfer of heat from one object to another object without contact. Conduction: is transfer of heat from one molecules to another of lower temperature. Convection: dispersion of heat by air current. Evaporations: continuous evaporation of the moisture from the respiratory tract. DrMohammmed Senana 27 Ways of heat loss: DrMohammmed Senana 28  This baby may lose heat by This baby will lose heat by evaporation This baby is exposed so may lost heat both convection and through a wet skin after birth. Drying via conductive air currents particularly conduction via direct contact and wrapping OR skin to skin contact plus if the room is cool with cool scales a hat is required DrMohammmed Senana 29 Neonatal Thermoregulation Neonatal Physiology o Neonatal physiology predisposes to poor thermal control o Wet skin at birth and high surface area to body ratio – lost heat via skin surface. o Immature hypothalamus o Lack of subcutaneous fat (term) and/or adipose tissue or brown fat (preterm) o Poor energy stores and limited brown fat = limited thermogenesis (heat production) DrMohammmed Senana 30 Neonatal Thermoregulation Neonatal Physiology o Most cooling of the newborn occurs immediately after birth. During the first 10 to 20 minutes, the newborn may lose enough heat for the body temperature to fall by 2-4°C if appropriate measures are not taken. Continued heat loss will occur in the following hours if proper care is not provided. The temperature of the environment during delivery and the postnatal period has a significant effect on the risk to the newborn of developing hypothermia DrMohammmed Senana 31 Neonatal Thermoregulation The Metabolic triangle There is an important relationship between maintaining adequate oxygenation, temperature blood glucose levels. A change in one affects the other. DrMohammmed Senana 32 Neonatal Thermoregulation DrMohammmed Senana 33 Neonatal Thermoregulation DrMohammmed Senana 34  Neonatal Thermoregulation Neutral thermal environment (NTE) NTE – is the optimum environmental temperature to ensure the lowest oxygen and energy expenditure The neonate may have to cope with either of two extremes – ‘THERMAL STRESS’ Excessive HEAT LOSS or excessive HEAT GAIN, both of which are stressors. Effects of Cold Decreased Surfactant efficiency Increased oxygen consumption – respiratory distress Increased utilisation of calorie reserves - hypoglycaemia Increased postnatal weight loss DrMohammmed Senana 35 Neonatal Thermoregulation DrMohammmed Senana 36 Neonatal Thermoregulation DrMohammmed Senana 37 Neonatal Thermoregulation Thermal care Monitor temperature & observe for instability Methods to keep baby warm / prevent heat loss – skin-to- skin contact, cover/wrap, hats, plastic wrapping for preterm neonates in delivery suite and then humidification Maintain the neutral thermal environment Incubator / Babytherm / Cot ? DrMohammmed Senana 38 Neonatal Thermoregulation Prevention of hypothermia Sources of heat loss Preventive measures Conduction Warming blanket Drapes or blankets Head covering Warmed solutions Convection Room temperature to 26.6ºC (80ºF) Incubator Keep neonate covered Radiation Radiant warmer Wrap neonate Warm room Evaporation Heated, humidified inspired gases AND body humidification Plastic bags / wrap for preterm (