Anesthesia Student Survival Guide.pdf - Index of

306 ● AnesthesiA student survivAl Guide
A small number of parturients (»0.5%) may develop a worsening
thrombocytopenia (i.e. low platelet count), liver dysfunction, hemolysis, and
anemia – termed HELLP syndrome. This is a life-threatening obstetric complication
which usually appears late in pregnancy or even after delivery. The
treatment for HELLP is delivery of the fetus.
Gastrointestinal
The obstetric patient is at increased risk for aspiration of gastric contents
because of:
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Impaired esophageal and intestinal motility
Stomach conformation and position changes
Decreased lower esophageal sphincter tone
Delayed gastric emptying during labor
Prophylactic measures aimed at reducing the risk of aspiration pneumonitis
are generally focused on modifying these risk factors. The most important
prophylactic measure is the avoidance of solid food during labor. Other
measures should be considered prior to surgery. Many routinely administer oral
sodium citrate, a non-particulate antacid. Sodium citrate quickly buffers existing
stomach acid, but at the expense of increasing gastric volume and possibly
causing nausea. The buffering capacity of sodium citrate is time-limited, and
it should therefore not be administered far in advance of surgery. H 2 -receptor
antagonists or proton-pump inhibitors can be used, but their beneficial effects
are likely delayed. Metoclopramide increases gastric emptying and lower
esophageal sphincter tone and is advocated by some practitioners. The possibility
of extrapyramidal reactions is a major drawback to its routine use.
Renal
Renal blood flow and glomerular filtration rate increase markedly during pregnancy.
As a result, the obstetric patient’s creatinine should be less than her non-pregnant
value. Additionally, total body water increases by »30%. Increased glomerular
permeability to proteins may lead to a mild proteinuria during pregnancy.
Musculoskeletal
As the gestation progresses, the lumbar spine becomes increasingly lordotic.
Lordosis hampers the interlaminar approach for the lumbar spinals and epidurals.
Although less feasible with advancing uterine size, good positioning