Anesthesia Student Survival Guide.pdf - Index of

342 ● AnesthesiA student survivAl Guide
Table 21.1 Spinal pain segments for the genitourinary system.
Organ Sympathetics Pain pathways
Kidney t8-l1 t10-l1
ureter t10-l2 t10-l2
Bladder t11-l2 t11-l2 (bladder dome)
s2–4 (bladder neck)
Prostate t11-l2 t11-l2s2–4
Penis l1 and l2 s2–4
scrotum s2–4
testes t10-l2 t10-l1
This innervation is important when one is administering anesthesia for stone
extractions. The bladder holds 400–500 cc of fluid and receives its innervation
from the hypogastric plexus (T11–12, S2–4) (Table 21.1).
The blood supply to the kidneys is via a single renal artery, which originates
inferior to the SMA. There are, however, many normal anatomical variants in
which multiple renal arteries are possible.
Patient Positioning
There are multiple patient positions utilized in urological surgery and the
anesthesiologist must be aware that there are physiological changes that
accompany these positions.
The lithotomy position (Fig. 21.1) is most commonly used for cystoscopies,
transuretheral resection of prostate or bladder tumor (TURP or TURBT), or
ureteroscopies. Placement in this position for greater than two hours may be a risk
factor for development of sensory neuropathies or rhabdomyolysis secondary
to compartment syndrome. This position increases upward displacement of
intra-abdominal contents, decreasing pulmonary compliance, forced residual
capacity and vital capacity, and increasing atelectasis. Elevating the legs also
increases venous return, cardiac output, and arterial blood pressure, but these
changes may not have clinically significant manifestations.
Placing the patient in the kidney rest position (also called the lateral
flexed position) is preferred for better access during renal surgery. Often an
axillary roll (usually a rolled towel) is placed between the table and upper
chest to ensure that the brachial plexus is free from compression or injury.
The lateral decubitus position has profound effects on creating ventilation–
perfusion mismatch and causes dependent atelectasis. Hemodynamically,