Anesthetic outcomes
Epidural anesthesia was used in 120 (41.4 %) patients, and spinal
anesthesia in the remaining 170 (58.6 %). Data regarding morphine use
are shown in Table 3. In 225 patients (77.6 %) morphine was used, of
which 124 (72,9 %) was intradural and 101 (84.9 %) was epidural. Mean
morphine dose was 58.0 µg (SD 16.6) in spinal anesthesia and 3 mg (SD
0.7) in epidural anesthesia. The use of morphine did not significantly
change the time to first micturition (10.9 h [IC95% 9.4 – 12.4] vs
12.2 h [IC95% 11.3 – 13.2], p = 0.170), the time to mobilization
(11.2 h [IC95% 9.8 – 12.6] vs 11.1 h [IC95% 8.8 – 13.3], p =
0.944) and the time to oral intake (7.5 h [IC95% 6.2 – 8.7] vs 7.4
h [IC95% 6.6 – 8.2], p = 0.949) compared to when no morphine was
administered. This effect remained unchanged when adjusting by modality
of anesthesia, spinal or epidural.
Regarding morphine adverse effects, the use of morphine did not increase
the incidence of nausea and vomiting (10.9 % [IC95% 3.3 – 18.6]
vs 8.5 % [IC95% 4.8 – 12.1], p = 0.546), pruritus (3.1 %
[IC95% 0 – 7.34] vs 3.1 % [IC95% 0.8 – 5.4], p = 1.000) and
urine retention (16.9 % [IC95% 7.8 – 26.0] vs 26.2 % [IC95%
20.5 – 32.0], p = 0.123).
When adjusting for the modality of neuraxial anesthesia, urinary
retention was significantly higher when morphine was used in spinal
anesthesia (8.7 % [IC95% 0.5 – 16.8] vs 21.8 % [IC95% 14.5 –
29.0], p = 0.049), but no differences were found with the use of
morphine when epidural anesthesia was performed (36.8 % [IC95% 15.2
– 58.5] vs 31.7 % [IC95% 22.6 – 40.8], p = 0.660). The
incidence of nausea, vomiting and pruritus was not significantly
different when adjusting for the modality of neuraxial anesthesia.
Finally, the administration of morphine was significantly associated
with a better pain control at 6 and 12 h at rest: NRS 3.0 [IC95% 2.4
– 3.6] vs 2.3 [IC95% 2.1 – 2.5] (p = 0.013) and NRS 2.5
[IC95% 2.0 – 3.0] vs 2,0 [IC95% 1.7 – 2.2], (p = 0.043),
respectively. Regarding pain at mobilization, we found no difference at
6 nor at 12 h: NRS 3.5 [IC95% 2.6 – 4.4] vs 3.3 [IC95% 3.0 –
3.5], (p = 0.540) and NRS 3.8 [IC95% 3.2 – 4.3] vs 3.4 [IC95%
3.1 – 3.7], (p = 0.308), respectively. When assessing pain control
according the type of neuraxial anesthesia, spinal anesthesia showed
better control both at 6 h at rest and at movement (p < 0.001
and p = 0.031 respectively) (Figure 2).