Anesthetic Techniques
General, local, and regional anesthesia have been used successfully
and safely for laparoscopy.
General Anesthesia
General anesthesia with endotracheal intubation and controlled
ventilation is the safest technique and therefore is recommended for inpatients and
for long laparoscopic procedures. During pneumoperitoneum, controlled ventilation
must be adjusted to maintain PETCO2
at
approximately 35 mm Hg. In our experience, this requires no more than a 15% to 25%
increase of minute ventilation, except when CO2
subcutaneous emphysema
develops. Increase of respiratory rate rather than of tidal volume may be preferable
in patients with COPD and in patients with a history of spontaneous pneumothorax
or bullous emphysema to avoid increased alveolar inflation and reduce the risk of
pneumothorax. Infusion of vasodilating agents, such as nicardipine,[105]
[155]
α2
-adrenergic receptor agonists,[88]
[110]
[111]
[112]
and remifentanil[81]
reduces the hemodynamic repercussions
of pneumoperitoneum and may facilitate management of cardiac patients (see Table
57-2
). There is apparently no clinical advantage to omitting nitrous oxide.
[294]
The success rate of in vitro fertilization
is not decreased by use of N2
O, suspected to affect oocyte function.[295]
The contribution of N2
O to nausea and vomiting is still controversial.
[230]
[231]
[233]
Whereas N2
O does not seem to be contraindicated for laparoscopic cholecystectomy,
[232]
omission of N2
O improves surgical
conditions for intestinal and colonic surgery. The choice of anesthetic technique
does not seem to play a major role in patient outcome.[294]
[296]
[297]
Propofol,
nevertheless, results in fewer postoperative side effects.[298]
[299]
[300]
[301]
Propofol anesthesia for laparoscopic pronuclear stage transfer, however, is associated
with lower clinical and ongoing pregnancy rates compared with isoflurane.[302]
IAP should be monitored, kept as low as possible to reduce hemodynamic and respiratory
changes, and not allowed to exceed 20 mm Hg. Increases in IAP can be avoided by
ensuring a deep plane of anesthesia. Whether profound muscle relaxation is necessary
for laparoscopy is not clear.[303]
Because of the
potential for reflex increases of vagal tone during laparoscopy, atropine should
be available for injection if necessary.
The laryngeal mask airway results in fewer cases of sore throat
and may be proposed as an alternative to endotracheal intubation,[304]
[305]
[306]
[307]
[308]
even if this device does not protect the airway
from aspiration of gastric contents.[309]
[310]
It allows controlled ventilation and accurate monitoring of PETCO2
.
However, decreased thoracopulmonary compliance during pneumoperitoneum frequently
results in airway pressures exceeding 20 cm H2
O. Because the laryngeal
mask airway cannot guarantee an airway seal above this pressure, its use for controlled
ventilation should be limited to healthy, thin patients.
General anesthesia in patients breathing spontaneously without
intubation can be performed safely and avoids tracheal irritation and administration
of a muscle relaxant. However, a report from the Centers for Disease Control and
Prevention revealed that almost one third of deaths associated with laparoscopic
procedures were related to anesthetic complications during general anesthesia without
intubation.[311]
This anesthetic technique must
be restricted to short procedures performed using low IAP and small degrees of tilt.
[25]
In these cases, the laryngeal mask airway
might
improve the safety of anesthesia for laparoscopy in patients breathing spontaneously
[304]
[307]
[312]
and is therefore recommended.
Local and Regional Anesthesia
Local anesthesia offers several advantages: quicker recovery,
decreased postoperative nausea and vomiting, early diagnosis of complications, and
fewer hemodynamic changes[313]
[314]
(see Chapter 14
, Chapter
43
, and Chapter 44
).
However, this anesthetic approach requires precise and gentle surgical technique
and may result in increased patient anxiety, pain, and discomfort during the manipulation
of pelvic and abdominal organs. For these reasons, local anesthesia is routinely
supplemented with intravenous sedation. The combined effect of pneumoperitoneum
and sedation can lead to hypoventilation and arterial oxygen desaturation.[315]
Success with local anesthesia requires a relaxed and cooperative patient, a supportive
operating room staff, and a skilled surgeon. IAP should be as low as possible to
reduce pain and ventilatory disturbances. Although laparoscopic tubal ligation may
be a good indication for local anesthesia, multiple constraints explain the lack
of enthusiasm of gynecologic laparoscopists for this anesthetic technique.[44]
Any other laparoscopic procedure that requires multiple puncture sites, considerable
organ manipulation, steep tilt, and voluminous pneumoperitoneum makes spontaneous
breathing difficult for the patient, results in discomfort, and must not be managed
with local anesthesia.[44]
Regional anesthesia, including epidural and spinal techniques,
combined with the head-down position can be used for gynecologic laparoscopy without
major impairment of ventilation.[23]
[316]
[317]
Laparoscopic cholecystectomy has been successfully
performed using epidural anesthesia in COPD patients.[318]
[319]
The metabolic response is reduced by regional
anesthesia.[320]
Globally, epidural and local anesthesia
share the same benefits and disadvantages. Regional anesthesia has the advantages
of reducing the need for sedatives and narcotics, produces better muscle relaxation
and can be proposed for laparoscopic procedures other than sterilization. Shoulder-tip
pain from diaphragmatic irritation and discomfort from abdominal distention are incompletely
alleviated using epidural anesthesia alone.[321]
Extensive sensory block (T4-L5) is necessary for surgical laparoscopy and may also
lead to discomfort. The epidural administration of opiates or clonidine, or both,
may help to provide adequate analgesia.[321]
The
hemodynamic effects of pneumoperitoneum under epidural anesthesia have not been studied.
Although sympathetic block may facilitate the development of vagal reflexes, vasodilation
and the avoidance of positive pressure ventilation may reduce the cardiovascular
changes described during pneumoperitoneum. Patient cooperation, an experienced and
skilled laparoscopist, reduced IAP, and tilt are necessary to guarantee the success
of epidural anesthesia, which should be avoided for long procedures. Regional anesthesia
can provide adequate relief of pain and discomfort in case of gasless laparoscopy,
avoiding most of the side effects of CO2
pneumoperitoneum[269]
[322]
(see Chapter
43
and Chapter 44
).
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