M.Noori-Shadkam, MD-MPH Neonatologist. Cessation of airflow for at least 20 seconds or accompanied...
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Transcript of M.Noori-Shadkam, MD-MPH Neonatologist. Cessation of airflow for at least 20 seconds or accompanied...
M.Noori-Shadkam, MD-MPHNeonatologist
Cessation of airflow for at least 20 seconds or accompanied by bradycardia or cyanosis. Bradycardia and cyanosis are usually present after 20 sec. of apnea. After 30 to 45 sec., pallor and hypotonia are seen, and infant may be unresponsive to tactile stimulation.
V Vickers 2006
Apnea is Associated with Many Clinical Conditions:
• Intraventricular bleedMay see hypoventilation, apnea or respiratory arrest
Subtle seizuresAlong with fluttering eyelids, drooling or sucking,
tonic posturing
Sepsis Bacterial (GBS, staph. Proteus, Listeria,
Coliforms Viral (RSV, paraflu, herpes, CMV Chlamydial NEC
V Vickers 2006
• Congestive Heart Failure– PDA and CHD– Due to decreased lung compliance– Respiratory muscle fatigue– Chest wall distortion– Hypoxemia
Respiratory Distress Syndrome Due to atelectasis, work of breathing, fatigue May lead to chronic lung disease
Anemia oxygen carrying capacity of blood Arterial pressure perfusing CNS
Polycythemia blood viscosity and blood flow to CNS begins at 2-4 hours of age
V Vickers 2006
High temperature of environment Feeding problems
overdistention of stomach aspiration GER (gastroesphogeal reflux) with or without
aspirationsdue to laryngospasmstimulation of irritant receptors in lower esophagus
causing ‘reflux apnea’some reflux is common (laundry issue only?)
Metabolic conditions Hypoglycemia Hypocalcemia Hypernatremia Alkalosis
Others Myelomeningocele Meningitis
Causes
• CNS: (Abnormality,Encephalitis,Meningitidis,ICH,…)
• Upper & lower Air way: (choanal A.,congestion, RDS,pneumonia,…) Cardiovascular:
(Malformation,hypotention,hypertention,…)Digestive system:(GER,NEC,Distention,…)Other:
(Sepsis,Anemia,Hypothermia,Hyperthermia,pain,metabolic disorder,…)
• Recurrent sequences of pauses in respiration lasting for 5-10 seconds and followed by 10-15 seconds of rapid respiration.
• As many as 25% of all preterm infants who weigh <1800 g (34 Week) have at least one apneic episode. Essentially all infants <28 Week have apnea.
PREMATURITY Impaired Inhibitory Oxygenation Reflexes
APNEA
Infection CNS pathologyMetabolic disorders
Specific causes of apnea
Preterm infants respond to a fall in inspired oxygen with a transient hyperventilation followed by hypoventilation and sometimes apnea.
The Respiratory Pump
• The neonatal diaphragm• The ribcage and chest wall
muscles
The Neonatal Diaphragm
In the relaxed state is located higher in the
ThoraxInc. insp. pressure
Muscle fibers• Type I: fast-oxidative, 20% fatigue
resistant• Type IIa: fast-oxidative, fatigue
sensitive• Type IIb: slow oxidative, fatigue
resistant
The Neonatal Diaphragm
Is attached to a more pliable chest wall
Distortion
Dec. tidal volume
The Neonatal Diaphragm
The Newborn is Predisposed to Fatigue of Resp. Muscles Because of:• The reduced number of fatigue resistant
fibers in the diaphragm• A pliable chest wall• The rapid RR, which minimizes relaxation
time for perfusion of the diaphragm• The work of breathing associated with CL and CW
Consequences of ApneaGas exchange is compromised due to:• PA CO2, PAO2•Extrapulmonary shunting•Muscle relaxation
Types of Neonatal Apnea
1.Central (diaphragmatic)2.Peripheral (obstructive)3.Mixed
• All preterm infants below 35 WG must be monitored for at least the first week after birth. Monitoring should continue until no significant apneic episode has been detected for at least 5 days.
• Because impedance apnea monitors may not distinguish respiratory efforts during airway obstruction from normal breaths, heart rate should be monitored in addition to, or instead of, respiration.
• BP should be measured frequently and hypotension with oliguria< 2 mL/kg/h should be treated accordingly
• Hct should be> 45% ???
1. Prevent hyperflexion of the neck2. Nurse the baby in prone position3. Set the thermal environment to obtain
a central temperature of 36.5-37⁰ C4. Minimize the duration and rate of
pharyngeal suction cont’d
5. Place the orogastric tube carefully 6. Avoid sudden gastric distension7. Continuous gastric feeding if apnea
occurs with gavage8. Warm air and oxygen to incubator
temperature
Nursing Management During Apneic Episode1.Check infant at once2.Cancel alarm3.Stimulate if there is no
obvious vomit4.Suction
cont’d
Nursing Management During Apneic Episode5. Give O2 via face mask in same
concentration as infant had been receiving
6. Summon help if infant does not respond
7. Document and report8. Intubation if indicated
Management of Idiopathic Apnea
• When apneic spells are repeated and prolonged, (i.e., more than 2 to 3 times/h.) or when they require frequent bag and mask ventilation, treatment should be initiated.
cont’d
Management of Idiopathic Apnea
• Diagnosis and treatment of specific causes• Nursing care• Nasal CPAP (4-6 cm H2O)• Methylxanthine therapy• Increased environmental O2 only as necessary
to maintain adequate baseline O2 saturation. Often associated with treatment of anemia
• Assisted ventilation if all else fails
Management of Idiopathic Apnea
A. General measures1. Diagnosis and treatment of specific causes2. SO2 : 85-95%3. Avoid reflexes that may trigger apnea. Suctioning of the pharynx should be done carefully, and oral feeding should be avoided.
cont’d
Management of Idiopathic Apnea
4. Position of extreme flexion or extension of the neck should be avoided, to reduce the likelihood of airway obstruction.
5. Avoid swings in environmental temperature.
cont’d
Management of Idiopathic Apnea
6. Consider a transfusions of PRBCs if the Hct is <25% and the infant has episodes of apnea and bradycardia that are frequent or severe while methylxanthine levels are therapeutic.
cont’d
Management of Idiopathic Apnea
B. Nasal CPAP (4-6 cm H2O) can reduce the number of mixed and obstructive apneic spells.
C. Methylxanthine (caffeine of theophylline) therapy, commencing with a loading dose followed by maintenance therapy, and serum level monitoring, especially for theophylline.
D. Assisted ventilation if all else fails
• PaO2 with increased lung volume & C• Work of breathing• Splitting of the upper airways• Elimination of the intercostal
inspiratory- inhibitory reflex
Pharmacologic Mechanisms for Methylxanthine • Competitive effect on adenosine receptors• Sensitivity of respiratory center to CO2• Afferent nerve traffic to brain stem• Catecholamine response• Central stimulation (inspiratory drive)• Improved skeletal muscle contraction• Improved metabolic homeostasis• Improved oxygenation via increased cardiac
output and decreased hypoxic episodes
Signs of Toxicity in Infants Receiving Theophylline• Failure to gain weight 10-20 µg/mL• Sleeplessness• Irritability • Tachycardia• Hyperglycemia• Vomiting 20 µg/mL• Diuresis/dehydration• Jitteriness > 20 µg/mL• Hyperreflexia• Cardiac arrhythmias > 40 µg/mL• Seizures