Respiratory Changes. Oxygen consumption increase 25-35% 100% in labor Minute ventilation ↑ in excess of CO2 mainly due to increased TV not RR tachypnea is considered abnormal sign Increased incidence of atelectaisis. ABG Changes. Causes of Acute Hypoxia.
100% in labor
tachypnea is considered abnormal sign
potential need of small ETT
&relaxed GE sphincter
& decreased FRC
33% no change 35% worsening 28% improvement.
pre existing respiratory alkalosis
stress dose should be given peripartum
Al Ansari Annals of Thoracic Medicine 2007
Hypercapnia harm on fetus
Hypercoagulopathy hormonal mediated
Stasis ( compressive effect of gravid uterus)
US a less sensitive test than in non pregnant
(very small risk in case of high clinical suspicion)
Morse Thromb Haemost 2004
This is 100 to 200 times < dose thought to produce a significant risk of fetal anomalies.
73% had normal scan 24% non diagnostic test
VQ utility is much higher than non pregnant
Chan Archive of Int Med 2002
The 7th ACCP Guidelines 2004
electrolytes & Acid base disturbances Odds Ratio >3
Lanska Stroke 2000