3 DISCUSSION
The patient in this case had been diagnosed with asthma many years
previously. To remove the endotracheal tube gently without irritating
the airway following the surgery, we changed the patient’s posture under
deep anesthesia. During this process, the patient severely bit the tube
and we were unable to provide ventilation for several minutes. Negative
pressure pulmonary edema occurred owing to severe negative intrathoracic
pressure due to airway obstruction caused by the severe biting of the
endotracheal tube, and a large quantity of bloody secretion was released
into the intubation tube. At first, NPPE was suspected, and treatment
was actively performed, including fluid restriction, diuretic
administration, exhalation positive breathing, and 100% oxygen
administration. Chest imaging performed after transfer to the intensive
care unit showed diffuse haziness in the right lung field and persistent
hemoptysis. Bronchoscopy findings showed no abnormal airway damage with
the exception of bloody secretion in the bronchus or airways.
According to Mondoni et al. 5 early bronchoscopy helps
detect bleeding sources. They suggested that if there is rebleeding, the
bronchoscopy must be performed again to examine the damaged airway area.
Hemoptysis caused by damage to the airways due to temporary negative
pressure is reported to naturally cease over time.
Shankar et al. 6 reported airway bleeding and
hemoptysis caused by temporary intrathoracic negative pressure resulting
in airway damage from airway obstruction due to various causes. This may
be misdiagnosed as pulmonary edema. The authors suggested that
hemoptysis may be caused by aspiration pneumonitis, airway injury,
polyps, arteriovenous malformation, and tumors.
Prost et al. 7 reported that NPPE was a rare (5%,
6/112) cause of DAH. Contou et al. 1 surveyed 149
patients in whom DAH was suggested over 36 years (1980-2015) and found
that 18 cases (12%) of DAH occurred in 15 patients through NPPE.
According to the study, almost 17 cases (94%) showed acute respiratory
failure with no other organ failure or circulatory failure. Hemoptysis
was found in 17 out of 18 cases (94%) and was the most common symptom,
but in only one case was more than 200 ml per day observed. Anemia was
observed in 10 cases (56%) and the average hemoglobin reduction was 1.5
g/dl. It was reported that 9 cases (50%) satisfied the DAH triad
(hemoptysis, anemia, and pulmonary infiltrates). In this case,
hemoptysis was the main symptom and anemia was not severe. The authors
reported that 16 cases (89%) showed alveolar or interstitial opacity of
both lungs, and only two cases (11%) demonstrated alveolar or
interstitial opacity in the right lung. In the present case, diffuse
opacity was observed in the right lung.
Schwarz et al. 8 reported pulmonary hemorrhage after
NPPE in surgical patients for the first time, and Goldenberg et al.9 reported two patients with tricuspid and pulmonary
insufficiency among six post-laryngospasm NPPE patients. Dolinski et al.3 reported pulmonary hemorrhage in patients with mild
tricuspid regurgitation due to increased pulmonary artery pressure after
NPPE. In this case, the patient had evidence of trivial MR in the
transthoracic echocardiography performed before surgery, but the
clinical symptom was not specific. It is thought that a more detailed
examination is needed to determine whether this mild MR was the cause of
unilateral DAH in this case, but such an examination was not performed
in this patient. In 2016, Han et al. 10 reported
negative pressure pulmonary hemorrhage that occurred after laryngospasm
in the postoperative period. In 2016, Choe et al. 11reported DAH after trans-femoral cerebral angiography in patients taking
clopidogrel, and there is a potential for DAH associated with
neuro-intervention in patients with hemoptysis and respiratory failure.
It was argued that patients who are taking anticoagulants should
carefully taper off the medicine prior to surgery and then begin it
again during or after surgery. In addition, the author stated that it is
better to protect less damaged lungs through active lung management such
as oxygen therapy, bronchodilators, endotracheal intubation, and
mechanical ventilation management in the treatment of patients with DAH.
NPPE by acute upper respiratory tract obstruction has been reported in
about 11% of cases. 12 Risk factors for postoperative
obstruction include obesity, short neck, obstructive sleep apnea, upper
respiratory surgery, hypertrophy, and difficulty in tracheal intubation.
While any factor that can cause gastrointestinal obstruction can cause
NPPE, the most common cause of NPPE during anesthesia is postoperative
laryngospasm.
It is reported that NPPE occurs within a few minutes of airway
obstruction and improves quickly after a day or two with active
treatment. Steroids, diuretics, and bronchodilators are known to help,
but their actions in these cases are not clear. 12
Papaianou et al. 13 reported that hemoptysis caused by
NPPE, which occurs during obstruction of the upper airways, such as
cases of laryngospasm, may be caused by negative-pressure
tracheobronchial injury or alveolar-capillary disruption. It is also
said that tension applied to the pulmonary-capillary wall may be caused
by alveolar-capillary membrane rupture. The authors stated said that
administration of succinylcholine (Sch) 80 mg and administration of an
unconsciousness inducing agent can prevent airway obstruction caused by
laryngospasm. 13 Both laryngospasm and biting were
possible causes of the patient’s airway obstruction in the present case.
The authors chose sugammadex for muscle relaxation reversal instead of
Sch in this case, focusing more on the visible biting rather than
laryngospasm as the cause of airway obstruction, and the patient quickly
stopped biting and was able to undergo ventilation.
Young male athletes are known to be at risk, and the syndrome occurs
rarely in patients with endotracheal intubation, but may also occur if
the patient bites the endotracheal tube during waking.14 Additional causes include excessive endotracheal or
laryngeal aspiration, as well as abnormal positioning of the mask.
However, there are few reports of pulmonary hemorrhage accompanied by
NPPE due to upper respiratory tract obstruction. 1,8
Schwartz et al. 8 reported that at the end of surgery,
negative intrathoracic pressure caused by upper airway obstruction after
extubation causes hypoxic respiratory failure. The authors noted that
post-anesthetic laryngospasm, strangulation, hanging, foreign body
airway obstruction, and OSA may be factors associated with NPPE.
Contou et al. 1 reported that the mechanisms of
development of NPPE were negative pressure formation in the thoracic
cavity, increased hydrostatic pressure in systemic and pulmonary
capillaries, and mechanical stress in the alveolar capillaries.
According to Contou et al., 1 first, - 2
~ - 5 cmH2O intrathoracic negative
pressure (- 100 cmH2O in severe cases) increases venous
return from peripheral blood vessels to the right atrium, simultaneously
increasing pulmonary blood flow, increasing trans-mitral capillary
pressure, and increasing pulmonary capillary and alveolar cavity
pressure and stress. The hydrostatic pressure rises. These changes
increase the trans-capillary pressure gradient, and the fluid exudes
into the interstitial space. The author also reported that elevated
central venous pressure interferes with lymphatic blood circulation.
Second, according to Contou et al., 1 the systemic
pressure increases owing to the secretion of norepinephrine due to
hypoxemia, hyper carbon dioxide, and anxiety, which increases the amount
of pulmonary blood flow. These effects reduce right ventricular
dilatation, ventricular wall movement, and cardiac output. As the
vascular resistance of the whole body increases, the resistance of the
left ventricular wall increases, and the left ventricle prevents the
blood flow.
Lastly, the authors reported that effusion from capillaries due to
physical alveolar-capillary membrane damage caused alveolar edema and
bleeding.
Unilateral pulmonary edema is a very rare complication. This
complication is mainly reported in cases of heart disease such as severe
mitral insufficiency or congestive heart failure, and there are few
reports in patients without heart disease. The syndrome can be caused by
prolonged lying on the lateral side or by excessive administration of
fluids in this position, and can occur after treatment in cases such as
pleural effusion or pneumothorax, or after re-expansion. MacLeod
syndrome, unilateral pulmonary agenesis, talc pleurodesis, trauma,
epilepsy, upper airway obstruction, pulmonary venous obstruction from
mediastinal fibrosis, post-lobectomy, unilateral mainstem intubation,
nitrogen mustard, and heroin-related pulmonary edema, and pregnancy may
all be causes of the syndrome. 15 The patient in the
present case was not in the lateral position and had no specific trigger
except for asthma from which he had been suffering for a long time.
As such, negative unilateral pulmonary edema and unilateral pulmonary
hemorrhage may result from many causes. In patients with acute
respiratory failure with hemoptysis and unilateral alveolar opacity, if
clinical findings are not consistent with pneumonia, it is important to
determine the presence of heart disease. Rapid initiation of active
treatment is important.
In summary, DAH is mainly caused by airway obstruction after surgery in
young and healthy male athletes. The patient in the present case
demonstrated acute respiratory failure accompanied by hemoptysis and
alveolar opacity on both sides, along with bilateral bleeding from both
sides and no bronchial damage. It is known that in older individuals,
there is a high possibility that there will not be enough negative
pressure to destroy the pulmonary capillaries, but the patient in this
case was an elderly male patient who had been diagnosed with asthma 70
years earlier, considered to be at increased risk and with damaged
sensitivity to the endothelial tissue of the bronchioles.
In a 78-year-old man treated with asthma for a long time, change to the
supine position at the end of general anesthesia resulted in severe
hypoxic respiratory failure, increased airway pressure, and
intra-tracheal tube after acute upper respiratory obstruction owing to
severe endotracheal tube biting. The patient experienced a large amount
of bloody secretions. Ultimately, the patient was discharged without
complications owing to appropriate treatment for negative pressure
pulmonary hemorrhage that occurred after endotracheal tube biting.
Anesthesiologists should take care not to induce airway irritation
during emergence of asthma, because DAH accompanied by NPPE was caused
in this case by airway irritation in an older patient with asthma
without known risk factors.