Sixty unpremedicated outpatients undergoing elective extracorporeal sh
ockwave lithotripsy (SWL) using a Dornier MPL 9000 lithotripter were r
andomly assigned to receive either propofol-alfentanil (PA group; N =
30) or midazolam-alfentanil (MA group; N = 30) by a patient-controlled
analgesia (PCA) device for sedation and analgesia, Although pain inte
nsity scores were lower after 20 minutes and sedation was more pronoun
ced in the MA group, both drug regimens produced satisfactory sedation
and analgesia and allowed the maximum number of shockwaves to be give
n, Alfentanil consumption was less in the MA group (P < 0.05), Both gr
oups were hemodynamically stable, The patients in the MA group had slo
wer ventilation rates, lower oxygen saturation, and higher end-tidal c
arbon dioxide levels, Use of MA was associated with more episodes of o
xygen desaturation to < 90% (30% vs, 11%; P < 0.05). One patient in th
e PA group and three patients in the MA group developed bradypnea (<10
breaths/min), Patient satisfaction was very high with the two sedativ
e-analgesic techniques, Propofol and midazolam, when given in combinat
ion with alfentanil using a PCA pump, may provide safe, effective anal
gesia and sedation during lithotripsy. Patient-controlled sedation and
analgesia may provide optimal conditions for SWL of urinary tract sto
nes and is a useful alternative to other forms of anesthesia and analg
esia.