pulmonary causes of peripartum hypoxia
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Pulmonary causes of Peripartum Hypoxia
By/ Islam Ezz Eldin OsmanAssistant lecturer of Anesthesia, intensive care and pain management
Ain Shams University, 2016
Introduction
The respiratory system undergoes a number of anatomic and physiologic changes during
the course of a normal pregnancy.
Some of these changes predispose to development of several acute pulmonary
disorders.
Pregnancy can also affect the course of some chronic pulmonary diseases, most notably,
asthma and sarcoidosis.
Chronic causes
• Pneumonia• Bronchial asthma• Tuberculosis• Interstitial lung
disease(Sarcoidosis, Cystic fibrosis,…etc)
Acute causes
• Venous thromboembolism
• Aspiration Pneumonia• Amniotic fluid embolism• ARDS• Pulmonary edema• Anesthetic
complications causing hypoxia
• Pneumothorax
Pulmonary causes of Peripartum Hypoxia
Pneumonia• Although infrequent, it is the most common non-
obstetric infection to cause complications as well as maternal and fetal mortality in the peripartum period.
• The most common bacterial pathogens include Pneumococcus and H.influenzae.
Diagnosis
History taking Clinical signs and examination
Investigations (CBC, culture results, …etc).
Pneumonia
Antibiotics (penicillins and cephalosporins are usually preferred)
Hospitalization , administration of IV antibiotics, oxygen therapy
In severe cases ICU admission and possible need for mechanical ventilation.
Management
Bronchial Asthma
Some studies suggest that poor
asthma control may have an
adverse effect on pregnancy
decreased birth weight
Preterm Birth
increased rates of neonatal and maternal mortality
Although the mechanisms for these findings are still unclear, maternal hypoxia and alkalosis may play a role.
Bronchial Asthma
Diagnosis
History or presence of
typical symptoms
Wheezes
Chest tightness
Cough
Dyspnea
Reversible airway obstruction on
spirometry
Bronchial Asthma
Management of Asthma
Attention should be paid to preventing fetal hypoxemia during attacks. Thus, administration of supplemental oxygen to keep maternal oxygen saturation greater than 95% is recommended.
Patient education on avoiding triggers for asthma, decresing frequency of attacks.
Drug therapy including :1. Reliever medications (short actingβ2agonists).2. Controller medications ( Corticosteroids, cromolyn
sodium, nedocromil sodium, sustained-release theophylline, and long-acting β-agonists).
Bronchial asthma
Special considerations during labor and delivery :
It is recommended that stable patients be given their usual medications during labor and
delivery.
If the patient has required chronic oral glucocorticoids, stress doses of parenteral steroids
should be given until 24 hours postpartum to prevent exacerbations during labor.
Oxytocin is the drug of choice for labor induction, a PGE2 suppository may be the safest of additional alternatives, since both
methylergonovine and PGF2α have been associated with bronchospasm and should be avoided.
Venous Thromboembolism
•Decreased venous tone and blood flow in the lower extremities, leading to venous stasis.•Compression of the inferior vena cava and left iliac vein by the uterus, leading to venous outflow obstruction and stasis.•An increase in several clotting factors and a decrease in fibrinolytic activity, leading to a hypercoagulable state.
Venous Thromboembolism
Symptoms of a DVT include calf pain and swelling, however some patients are asymptomatic.
Clinical symptoms of pulmonary embolism (PE) include the sudden onset of dyspnea, tachypnea, tachycardia, and pleuritic chest pain. In massive
PE, arrhythmias, syncope, and cardiovascular collapse may develop.
Venous Thromboembolism
Diagnosis
DVT
Venous Thromboembolism
Anticoagul
ants
• Warfarin is contraindicated
• Heparin is the drug of choice
• Low molecular weight heparin is a solid alternative.
Thro
mbolytic th
erapy
• Pregnancy is a relative contraindication to the use of thrombolytic therapy, and these should be used only in patients suffering from massive PE and cardiovascular instability
Vena cava
l filter
•The use of vena cava filters is indicated for those patients who cannot be anticoagulated or for those who have recurrent PE while on adequate anticoagulant therapy.
Management of DVT and PE
Amniotic Fluid Embolism
Amniotic fluid containing :
o Fetal Debriso Desquamated
cellso Meconiumo Lanugo hairo Mucin
Damaged fetal
membrane
Disruption of uterine veins
Sufficient Pressure gradient
Amniotic Fluid
Embolism
Pathogenesis
Amniotic Fluid Embolism
Premature rupture of membranes
Advanced age
Use of uterine stimulants
Multiparity
Meconium staining of amnion
Occurs during / shortly after delivery
Severe Dyspnea Hypoxemia, cyanosis
Skin rash may be present
CVS collapse
Seizures, Coma
DIC , ARDS
Sudden onset
Mechanical obstruction of the pulmonary
vasculatureAlveolar capillary
leak (ARDS) secondary to
extensive microembolic
insult.
Pulmonary edema due to left ventricular
failure. Anaphylaxis
due to sudden exposure to fetal antigen
Risk factors Clinical Picture
Amniotic Fluid Embolism
Diagnosis
•Mainly by exclusion, the only sure way of diagnosis is by cytologic examination of blood removed from the distal lumen of a pulmonary artery catheter showing contents of amniotic fluid
Treat
ment
•Largely supportive•Mortality ranges from 80-90 %
Aspiration pneumonia
Clini
cal picture
•Tachypnea•Cyanosis•Hypoxemia•Hypotension•Tachycardia•Bronchospasm
Diagn
osis
•Witnessed event•Suspicion supported by radiographic findings of isolated or diffuse lung infiltrates.
Trea
tme
nt
•Mainly supportive:•Oxygen•Bronchodilators•Ventilation
•Antibiotics should be started early if bacterial infection is suspected
Adult Respiratory Distress Syndrome
ARDS is diagnosed on the basis of:
Acute onset (within 1 week of known clinical insult)
Bilateral opacities on CXR (not explained by effusions, collapse, or nodules)
Respiratory failure not fully explained by heart failure or fluid overload (objective assessment such as echocardiogram recommended)
Severity of ARDS• Mild: 300 ≥PaO2/FiO2 >200 with PEEP >5 cm H2O• Moderate: 200 ≥PaO2/FiO2 >100 with PEEP >5 cm H2O• Severe: 100 ≥PaO2/FiO2 with PEEP >5 cm H2O.
Adult Respiratory Distress Syndrome
•Eleminate the cause if possible •Deliver the baby if patient can tolerate and baby is at safe gestational age•Supportive care:•IV fluids•Nutritional support•Antiinflammatories ( steroids)•Antibiotics•Cardiovascular support•Ventilatory support weather invasive or non invasive•ECMO
Pulmonary edema with pregnancy
Extra pulmonary causes
Preeclampsia
Tocolytic pulmonary edema
Cardiogenic pulmonary edema
Etc…
Advanced pneumonia
Aspiration pneumonia
ARDS
Negative pressure pulmonary edema
Negative pressure pulmonary edema (NPPE)
3 Mechanisms have been incriminated in NPPE
Marked negative intrathoracic pressure
Increased venous return
Sudden increase in pulmonary
microvascular pressure
Hypoxia and metabolic acidosis increase
vasoconstriction at the pre capillary level
Elevation of pulmonary
microvascular pressure alters pulmonary
capillary permeability
Acute relief of obstruction
Dissapearance of autoPEEP
Negative intrapulmonary
pressure
Pulmonary Edema
Negative pressure pulmonary edema (NPPE)StridorWorking accesory muscles of respirationHypoxia and declining SPO2
Frothy pink sputum
Clinical Picture
Develops within one hour, may be delayedMainly based on history of precepitating event.Chest Xray supports diagnosis
Diagnosis
o First priority is to releif obstruction and correct hypoxemia
o Mainainance of airway patency and supplemental O2
o Diuretics are often administeredo Ventilatory support by non-invasive or
invasive modalities may be required
TreatmentTreatment
• Spontaneous pneumothorax rarely occurs during pregnancy and labor
• Traumatic pneumothorax may occur and needs prompt evaluation and control
Causes
• Pleuritic chest pain associated with dyspnea, tachypnea and cyanosis
• Unilateral diminished air entry and limited chest expansion
Clinical presentation
• History and clinical examination• Confirmation by imaging studies if possibleDiagnosis
Pneumthorax
Pneumothorax
• Conservative in mild cases, hospitalization, supplementary O2 and follow up.
• Needle aspiration, needle drainage and chest tube insertion.
• For patients who have not received definitive surgical therapy, epidural anesthesia and forceps assistance are recommended to prevent increased intrathoracic pressure due to the expulsive efforts during the second stage of labor and possible worsening or recurrence of pneumothorax.
Treatment
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