What
anesthetic techniques can be used for laparo-scopic surgery?
General, regional, and local anesthesia have
all been used successfully and safely for laparoscopy.
General anesthesia with endotracheal intubation
and controlled ventilation is one of the more commonly used techniques. Here,
the airway is protected and ETCO2 can be controlled to levels
approximating 35 mmHg. IAP and airway pressures should be monitored. IAP should
be kept below 20 mmHg, ideally between 12 and 15 mmHg. Increases in IAP should
be avoided by ensuring an ade-quately deep plane of anesthesia. The need for
muscle relax-ation is controversial. Peak inspiratory pressures >40 cm H2O
predispose to barotrauma and should be reported to the surgeon if they occur.
This is of particular importance in those with pre-existing bullous disease or
in those with a history of barotrauma. The management of increased peak airway
pressures may involve decreasing intra-abdominal pressure, lessening the
Trendelenburg positioning, and decreasing tidal volumes and inspiratory flow
rates.
The laryngeal mask airway (LMA) is an
alternative to endotracheal intubation. This device does not protect the airway
from aspiration of gastric contents. Controlled ven-tilation and monitoring of
ETCO2 are possible. As peak air-way pressures are frequently greater
than 20 cmH2O during these operations, there is no guarantee that
the airway seal provided by the LMA will be preserved. Consequently, its use is
strongly cautioned. If employed, it should be reserved for thin individuals
without intrinsic increased risks for aspiration. In emergency situations,
however, an airway maintained with an LMA is better than no airway at all.
Gynecologic laparoscopic procedures can be
performed under spinal or epidural anesthesia. The advantage of regional
anesthesia is the reduced need for sedatives and narcotics when compared with
local anesthesia with supple-mental sedation. However, shoulder tip pain and
discomfort secondary to abdominal distention are incompletely allevi-ated under
epidural anesthesia. A sensory block from T4 to L5 is
needed and may also be uncomfortable. The hemo-dynamic effects of the pneumoperitoneum
under epidural anesthesia have not been studied. It is necessary to have a
cooperative and motivated patient, a skilled laparoscopist, and minimal IAPs
and Trendelenburg positioning for this method to be successful. Patients
considered a “full stom-ach” are not the best candidates for this technique.
The increases in intra-abdominal and intragastric pressures along with the
frequently used Trendelenburg positioning and the need for significant
intravenous sedation all increase the risks of regurgitation and potential
aspiration when the airway is unprotected.
Local anesthesia with sedation offers several
advantages compared with general anesthesia: quicker recovery, decreased
incidence of postoperative nausea and vomiting, and fewer hemodynamic changes.
The sequelae of general anesthesia, such as sore throat, muscle pain, and
airway trauma, may also be avoided.
Success with local anesthesia also requires a
relaxed, cooperative and motivated patient, a supportive operating room staff,
and a skilled surgeon. Any laparoscopic proce-dure that requires multiple
puncture sites, considerable organ manipulation, steep tilt, or extensive
pneumoperi-toneum should not be managed with this method. Diagnostic
laparoscopy and sterilization procedures are two operations that may be
performed under this technique.
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