\SPECIAL CONSIDERATIONS FOR PATIENTS UNDERGOING LUNG RESECTION
Massive hemoptysis is usually defined as
>500–600 mL of blood loss from the
tracheo-bronchial tree within 24 hr. The etiology is usu-ally tuberculosis,
bronchiectasis, or a neoplasm, or complication of transbronchial biopsies.
Emergency surgical management with lung resection is reserved for “potentially
lethal” massive hemoptysis. In most cases, surgery is usually carried out on an
urgent rather than on a true emergent basis whenever pos-sible; even then,
operative mortality may exceed 20% (compared with > 50% for medical manage-ment). Embolization of the
involved bronchial arter-ies may be attempted. The most common cause of death
is asphyxia secondary to blood in the airway. Patients may be brought to the
operating room for rigid bronchoscopy when localization is not possible with
fiberoptic flexible bronchoscopy. A bronchial blocker or Fogarty catheter
(above) may be placed to tamponade the bleeding, or laser coagulation may be
attempted.
Multiple large-bore intravenous
catheters should be placed. Sedating drugs should not be given to awake, nonintubated,
spontaneously ven-tilating patients because they are usually already hypoxic;
100% oxygen should be given continu-ously. If the patient is already intubated
and has bronchial blockers in place, sedation is helpful to prevent coughing.
The bronchial blocker should be left in position until the lung is resected.
When the patient is not intubated, a rapid sequence induc-tion (ketamine or
etomidate with succinylcholine) is used. Patients usually swallow a large
amount of blood and should be considered to have a full stom-ach. A large
double-lumen bronchial tube is ideal for protecting the normal lung from blood
and for suctioning each lung separately. If any difficulty is encountered in
placing the double-lumen tube, or its relatively small lumens occlude easily, a
large (>8.0-inner diameter) single-lumen tube
may be used with a bronchial blocker to provide lung isolation.
Pulmonary cysts or bullae may be
congenital or acquired as a result of emphysema. Large bullae can impair
ventilation by compressing the surrounding lung. These air cavities often
behave as if they have a one-way valve, predisposing them to progressively
enlarge. Lung resection may be undertaken for pro-gressive dyspnea or recurrent
pneumothorax. The greatest risk of anesthesia is rupture of the air cavity
during positive-pressure ventilation, resulting in tension pneumothorax; the
latter may occur on either side prior to thoracotomy or on the nonopera-tive
side during the lung resection. Induction of anesthesia with maintenance of spontaneous
venti-lation is desirable until the side with the cyst or bul-lae is isolated
with a double-lumen tube, or until a chest tube is placed; most patients have a
large increase in dead space, so assisted ventilation is nec-essary to avoid
excessive hypercarbia. The use of N2O is contraindicated in patients withcysts
or bullae because it can expand the air space and cause rupture. The latter may
be signaled by sudden hypotension, bronchospasm, or an abrupt rise in peak
inflation pressure and requires immedi-ate placement of a chest tube.
Lung abscesses result from primary
pulmonary infections, obstructing pulmonary neoplasms (above), or, rarely,
hematogenous spread of sys-temic infections. The two lungs should be isolated
to prevent contamination of the healthy lung. A rapid-sequence intravenous
induction with tracheal intu-bation with a double-lumen tube is generally
recommended, with the affected lung in a depen-dent position. As soon as the
double-lumen tube is placed, both bronchial and tracheal cuffs should be
inflated. The bronchial cuff should make a tight seal before the patient is
turned into the lateral decubitus position, with the diseased lung in a
nondependent position. The diseased lung should be frequently suctioned during
the procedure to decrease the like-lihood of contaminating the healthy lung.
Bronchopleural fistulas occur following
lung resec-tion (usually pneumonectomy), rupture of a pul-monary abscess into a
pleural cavity, pulmonary barotrauma, or spontaneous rupture of bullae. The
majority of patients are treated (and cured) conser-vatively; patients come to
surgery when chest tube drainage has failed. Anesthetic management maybe complicated by the inability to effectively ven-tilate the patient with
positive
pressure because of a large air leak, the potential for a tension
pneu-mothorax, and the risk of contaminating the other lung if an empyema is
present. T he empyema
isusually drained, prior to closure of the fistula. correctly placed double-lumen
tube greatly simplifies anesthetic management by isolating the fistula and
allowing one-lung ventilation to the nor-mal lung. The patient should be
extubated as soon as possible after the repair.
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