Anesthesia Considerations in Pregnancy

Anesthesia Considerations in Pregnancy • airway ■ possible difficult airway as tissues becomes edematous and friable especially in labour • respiratory ■ decreased FRC and increased O2 consumption cause more rapid desaturation during apnea • cardiovascular system ■ increased blood volume > increased RBC mass results in mild anemia ■ decreased SVR proportionately greater than increased CO results in decreased BP ■ prone to decreased BP due to aortocaval compression – therefore for surgery, a pregnant patient is positioned in left uterine displacement using a wedge under her right flank • central nervous system ■ decreased MAC due to hormonal effects ■ increased block height due to engorged epidural veins • gastrointestinal system ■ delayed gastric emptying ■ increased volume and acidity of gastric fluid ■ decreased LES tone ■ increased abdominal pressure ■ combined, these lead to an increased risk of aspiration – therefore for surgery, a pregnant patient is given sodium citrate 30 cc PO immediately before surgery to neutralize gastric acidity Options for Analgesia during Labour • psychoprophylaxis – Lamaze method ■ patterns of breathing and focused attention on fixed object • systemic medication ■ easy to administer, but risk of maternal or neonatal respiratory depression ■ opioids most commonly used if delivery is not expected within 4 h • inhalational analgesia ■ easy to administer, makes uterine contractions more tolerable, but does not relieve pain completely ■ 50% nitrous oxide • neuraxial anesthesia ■ provides excellent analgesia with minimal depressant effects ■ hypotension is the most common complication ■ maternal BP monitored q2-5min for 15-20 min after initiation and regularly thereafter ■ epidural usually given as it preferentially blocks sensation, leaving motor function intact Options for Caesarean Section • neuraxial: spinal or epidural • general: used if contraindications or time precludes regional blockade