Asphyxia of the newborn. Birth trauma

Prof. H.A. Pavlyshyn

Definition

WHO: Asphyxia is incapacity of newborn to begin or to support spontaneous respiration after delivery due to breaching of oxygenation during labor and delivery

Asphyxia is absense or ineffective respiration of newborn of 1 minute old with Apgar score less than 4

Definition

Ukraine: Asphyxia of newborn as a nosological form is conditioned by causes when severe maternal-placental and (or) umbilical blood flow is disturbed

and leads to development

of metabolic acidosis

Asphyxia

Asphyxia: means “a stopping of the pulse”, but more useful is a definition of impaired or interrupted gas exchange.

These situations can take place: a. Intrauterine: the gas exchange depends on the

function of placenta, and the blood-flow in the umbilical vessels.

b. Postnatal: after delivery the gas exchange takes place in the pulmonary vesicles or alveoli and depends on the function of the heart, lungs and brain.

Causes of Asphyxia

Fetal hypoxia: Mother: hypoventilation during anesthesia, cyanotic heart

disease, respiratory failure or carbon monoxide poisoning. Low maternal blood pressure as a result of the hypotension

that may cause compression of the vena cava & aorta by the gravid uterus

Premature separation of the placenta; placenta previa Impedance to the circulation of blood through the umbilical

cord as a result of compression or knotting of the cord Uterine vessel vasoconstriction by cocaine, smoking Placental insufficiency from numerous causes, including

gestosis, eclampcia, toxemia, postmaturity Extremes in maternal age (< 20 years or >35 years) Preterm or postterm gestation.

Causes of Asphyxia

Intrapartus asphyxia: More frequently inadequate obstetric aid Using forceps, vacuum extraction, cresteller,

caesarean section (immediate) Trauma: narrow pelvis, malpresentation Extremely rapid or prolonged labor Multiple gestation Drugs depression of CNS: anesthesia, sedatives &

analgesics Meconium-stained amniotic fluid

Causes of Asphyxia

Postnatal hypoxia: Anemia due to severe hemorrhage or hemolytic

disease Shock from adrenal hemorrhage, intraventricular

hemorrhage, overwhelming infection, massive blood loss

Failure to breathe due to a cerebral defect, narcosis or injury

Failure of oxygenation resulting from of cyanotic congenital heart disease or deficient pulmonary function

Predisposing risk factors for asphyxia are:

Multiple gestation; Placental abruption; Placenta previa; Preeclampsia; Meconium-stained amniotic fluid; Fetal bradycardia; Prolonged rupture of fetal membranes; Extremes in maternal age (senior 35 y, junior 20 y);

Maternal diabetes; Maternal use of illicit drugs;

Apgar Score of the Newborn

SIGNSCORE 0

1 2

Heart rate Absent <100 beats/min >100 beats/min

Respiratory effort Absent Weak, irregular Strong cry

Muscle tone Flaccid Some flexion Well

Reflex irritability (response to catheter in nostril)

No Grimace Cough or sneeze

Skin colour Blue, pale

extremities blue

pink

Postnatal symptoms of ASPHYXIAMILD ASPHYXIA

° The infant who experiences mild asphyxia initially will be depressed. This is followed by a period of hyperalertness, which resolves within 1 or 2 days.

° Clinical symptoms: hyperalertness (jitteriness), increased irritability and tendon

reflexes, exaggerated Moro response;

° There are no local signs ° The prognosis is excellent for normal

(good) outcome.

CRITERIA OF MODERATE ASPHYXIA

° The infant who experiences moderate asphyxia will be very depressed. This is followed by a prolonged period of hyperalertness and hyperreflexia.

° Clinical symptoms: lethargy, hypotonia suppressed reflexes with or without

seizures Generalised seizures often occur 12 to

24 hours after episode of asphyxia, but are controlled easily, resolving in a few days regarding of therapy.

° The prognosis is variable (20-40% with abnormal outcome).

CRITERIA OF SEVERE ASPHYXIA

° Severe metabolic or mix acidosis pH ≤ 7.00 in arterial blood of umbilical vessels;

° Assessment by Apgar is 0-3 during more than 5 minutes;

° Neurological symptoms such as general hypotonia, lethargy, coma, seizures, brainstem, autonomous dysfunction;

° Evidence of multiorgan system dysfunction in the

immediate neonatal period - damage of vital organs (lungs, heart and others) in fetus or newbon;

CRITERIA OF SEVERE ASPHYXIA

° Severe asphyxia is associated with coma, intractable seizures activity, cerebral oedema, intracranial haemorrhage.

° The infant often became progressively more depressed over the first 1 to 3 days, as a cerebral oedema develops, and death may occur during this period.

Survival is usually associated with poor long-term outcome (100% with abnormal outcome);

Acute complications associated with Asphyxia

hypoxic-ischemic encephalopathy (HIE) hypotension seizures persistent pulmonary hypertension hypoxic cardiomyopathy necrotizing enterocolitis acute tubular necrosis adrenal hemorrhage and necrosis Hypoglycemia, polycytemia disseminated intravascular coagulation

Hypoxic-ischemic cerebral injury – HIE (encephalopathy)

Is caused by a combination of hypoxemia, ischemia, that results in a decreased supply of oxygen to cerebral tissue

During perinatal asphyxia, birth trauma, hypercapnia and acidosis may contribute further to the cerebral insult.

Sarnat criteria Level of consciousness Neuromuscular control Muscle tone Posture Stretch reflexes Segmental myoclonus Complex reflexes: Suck, Moro,

oculovestibular tonic neck Autonomic function

Pupils Respirations Heart rate Bronchial & salivary secretions Gastrointestinal motility Seizures EEG Duration of symptoms

Sarnat criteria

Clinical symptoms and metabolic derangement –

blood sample from the umbilical artery - low pH (< 7, 00) - indicates the intrapartum asphyxia.

Renal and/or cardiac failure

Assessment of the brain: EEG

Serial recordings are almost necessary.

Low voltage. Burst-suppression patterns or electrical inactivity are associated with bad prognosis.

Rapid resolution of EEG abnormalities and/or normal interictal EEG are associated with a good prognosis.

DIAGNOSIS

Ultrasound and Doppler technique Ultrasound: to measure the growth of the fetus. The growth

retarded fetus is in a great risk of developing asphyxia. Ultrasound can be useful in premature newborns.

Doppler techniques: to measure the blood flow in the umbilical vessels or aorta. A low flow or decreasing flow indicates a fetus

in risk of asphyxia.

Computed tomography: CT is of major value both acutely during the neonatal period and later in childhood. The optimal timing of CT scanning is between 2 and 4 days.

ABC resuscitation

A- Airways (maintenance of passableness of airway)

B- breathing (stimulation of breathing) C- circulation (support of circulation) D-drug

ABC resuscitation Step A- immediately after delivery the

infant’s head should be placed in a neutral or slightly extended position

Roller towel under the shoulders

And airway established by clearing the mouth, then the nose by rubber bag

If it is inadequate we must use step B. At first the tactile stimulation should

be given to newborn, for example - gentle flicking of the feet or heel

ABC resuscitation

or rubbing of the back

If meconium is present in amniotic fluid, after sucking of mouth and nose we must

suck a pharynx by tube after laryngoscope

If these measures are inadequate, mechanical ventilation should be initiated,

using mask and bag ventilation

If ventilation is adequate supplemental oxygen may be given to improve

heart rate or skin colour

If mechanical ventilation does not improve the respiration, heart rate or colour skin, the following step is “C”-circulation.

At first the assessment of heart rate is necessary

If heart rate is less than 60 beats/minute, or between 60 and 80 beats and is not improving,

cardiac compression must be performed

ABC resuscitation

Big fingers must lie on the sternum, other fingers should lie under the back of newborn

ABC resuscitation If heart rate is less then 80 beats per minute the

cardiac compression should be continued. If heart rate is 80 beats per minute or more the

cardiac compression should be stopped .

Birth trauma

The term “Birth trauma” is used to denote mechanical and anoxic trauma incurred by the infant during labor and delivery.

The process of birth is associated with compressions, contractions, and tractions.

Birth trauma

When fetal size, presentation or neurological immaturity complicate this event, such intrapartum forces may lead to

tissue damage, edema, hemorrhage or fracture in the neonate.

The risk of birth injury Small maternal stature Maternal pelvic anomalies Extremely rapid Prolonged labor Using forceps, vacuum extraction Versions and extraction Deep transverse arrest of descent of presenting

part of fetus Oligohydramnions Abnormal presentation (i.e. breech)

The risk of birth injury Very low birth weight infant or extreme

premature Postmature infant(> 42 week of gestation) Cesarean section Fetal macrosomia Large fetal head Fetal anomalies

(see teratoma)

Classification of birth injuries

I. Soft-tissue injuries - caput succedaneum - subcutaneous and retinal hemorrhage, petechia - ecchymoses and subcutaneous fat necrosis

Classification of birth injuries

II. Cranial injuries cephalohematoma fractures of the skull

Classification of birth injuries

III. Intracranial hemorrhage subdural hemorrhage subarachnoid hemorrhage intra- and periventricular

hemorrhage parenchyma hemorrhage

Classification of birth injuries

IV. Spine and spinal cord fractures of vertebra Erb-Duchenne paralysis Klumpke paralyses Phrenic nerve paralyses Facial nerves palsy

Classification of birth injuries

V. Peripheral nerve injuriesVI. Viscera (rupture of liver, spleen and adrenal hemorrhage) VII. Fractures of bones.

Birth trauma

Petechiae and ecchymosis are common manifestation of birth trauma in the newborn. Petechiae of the skin of the head and neck are common. These lesions resolve spontaneously within 1 week.

They are caused by a sudden increase in intrathoracic pressure during labor when the fetus passes through the birth canal.

They are temporary and are the result of normal course of delivery.

If the etiology is uncertain, studies to rule out coagulation disorders or infections etiology are indicated.

Birth trauma

Caput succedaneum is a subcutaneous extraperiosteal fluid collection in the presenting part of fetus

is caused by infiltration of subcutaneous soft tissue in the presenting part resulting from pressure in birth canal

with poorly defined margins it may extend across the midline over suture lines This swelling is resolved rather quickly within several days

post partum.

Cephalohematoma is a subperiosteal collection of blood resulting

from rupture of the blood vessels between the skull and pereostium

its does not extend over suture lines between adjacent bones.

Its occurrence is commonly on one side of the head

The extent of hemorrhage may be severe enough to present as anemia and hypotension with secondary hyperbilirubinemia.

Birth trauma

• It may be a focus of infection leading to meningitis, particularly when there is a concomitant skull fracture.

Skull X-rays should be obtained if there are CNS symptoms,

if the hematoma is very large or if the delivery was very difficult.

Resolution occurs over 1 to 2 month, occasionally with residual calcification as a thrombus.

Birth trauma INTRACRANIAL HEMORRHAGE

Occurs in 20% to more than 40% of infants with birth weight under 1500 gm,

is less common among more mature infants. Intracranial hemorrhage may occur in the subdural,

subarachnoid, intraventricular or intracerebral regions. Subdural and subarachnoid hemorrhage follow head trauma

(e.g. in breech, difficult and prolonged labor and after forceps delivery).

Other forms of intracranial bleeding are associated with immaturity and hypoxia.

Predisposing factors of IVH premature respiratory distress syndrome, apnea pneumothorax congestive heart failure presence of patent ductus arteriosus hypoxic ischemic or hypotensive injuries increased venous pressure hypervolemia, hypertensia

The structural and functional factors of IVH in low-birth-weight infants

poor structural support of germinal matrix vessels relatively large blood flow to deep cerebral

structure hypoxic-ischemic injury to germinal matrix or its

vessels

Clinical manifestation of IVH

Absent Moro reflex Weakness, seizures, muscular twitching Poor muscle tone Hypotonia Lethargy excessive somnolence Pallor or cyanosis Respiratory distress Jaundice

Clinical manifestation IVH Bulging anterior fontanel Temperature instability Hypotonia Brain stem signs

(apnea, lost extraocular

movements,

facial weakness,

abnormal eye signs)

Laboratory correlates of blood loss

Metabolic acidosis Low hematocrit Hypoxemia, hypercarbia Respiratory acidosis Thrombocytopenia and prolongation of

prothrombin time (PT)

Diagnosis IVH

History Clinical manifestation Transfontanel cranial ultrasonography Computed tomography Glucose level CBC - complete blood count Lumbar puncture

Outcomes and prognosis Patients with massive bleeding

have a poor prognosis. About 10-15% infants may develop

post hemorrhagic hydrocephalus

and chronic neurological pathology

Spinal cord

Spinal cord injuries are commonly caused by strong traction when

the spine is hyper extended forceful longitudinal traction on the trunk while

the head is still firmly engaged in the pelvicshoulder dystocia

Clinical data

Areflexia Loss of sensation Complete paralysis of voluntary motion

below the level of injury Epidural hemorrhage Apnea

8

7

9

4

5

6

3

2

1

Roots

Trunks

Cords

Nerves

ANATOMY OF THE BRACHIAL PLEXUS

UlnarMedianRadial

7

8

9

5

Lateral PosteriorMedial

4

6

Upper Middle Lower

1

2

3

Brachial Palsy

Risk Factors Shoulder dystocia Neonatal birthweight (macrosomia) Instrumental vaginal delivery Breech presentation Prior infant with brachial palsy

Erb Palsy – Upper trunk plexopathy

Injury to the 5th and 6thcervical nerves (C5-C6 root avulsion)

Arm falls limply to the side of the body when passively adducted

Affected arm adduction & internal rotation Elbow extended & forearm pronated Wrist is flexed “Waiters tip” position Moro, biceps and radial reflexes absent +/- Horner syndrome

Klumpke palsy

Lower trunk (C8, T1) injury Poor grasp, proximal function preserved Absence of movements of the wrist Horner syndrome (ipsilateral ptosis and miosis) if the thoracic spinal nerve is involved

Flail arm• Injury to entire plexus

Phrenic nerve palsy

Injury to the C3,C4 or C5

Brachial plexus injury RDS Paradox (upward) movement during

inspiration

Clavicular fracture

Most common Crepitus, palpable bony irregularity Sternoclaidomastoid

muscle spasm Cry during movement of upper

extremities

Intraabdominal injures – target organ

Liver Spleen Adrenal gland (breech presentation)

Intraabdominal injures

Sudden presentation Shock Abdominal distension Bluish discoloration, jaundice, pallor Poor feeding Thachypnea, tachycardia history: difficult delivery

Diagnosis.

A thorough neurological examination Ultrasound examination of the brain EEG intracranial pressure measurement computed scanning are valuable.

Treatment The rapid responders from anoxia need observation in

the nursery for only 12 to 24 hours. These babies should be kept in ward, with a minimal

noise level or in the nursery. Acidosis, hypocalcaemia and hypoglycemia need

correction. Seizures should be controlled with phenobarbital

Treatment