Michelle Torres
1/7/09
CASE: 30 y.o. male with right thyroid mass who underwent right thyroid lobectomy.
Patient with h/o hypertyroidism and hyperlipidemia, otherwise healthy. Surgery was
uneventful. However, after extubation, patient starting biting on his tongue and lip, and
starting coughing blood-tinged secretions. He was suctioned after an oral airway was
placed, and he was taken to the PACU.
In the PACU, patient appeared to be tachypneic and was using his accessory muscles of
respiration. Rales were present bilaterally on physical exam, and he was coughing up
pinkish secretions. He satted in high 80s on 5L FM, which was subsequently increased to
10L FM with no improvement. Sat dropped to as low as 77%. ABG was performed: pH
7.26, pCO2 51, pO2 54, base excess -5, bicarb 22.4, O2 sat 82.9%.
Pre-op CXR: no active cardiopulmonary disease
CXR in PACU: Hazy diffuse lung opacification likely represents noncardiac edema
Why would a fairly healthy young male have hypoxia after an uneventful right thyroid
lobectomy? NEGATIVE PRESSURE PULMONARY EDEMA (NPPE)
What is the cause of NPPE?
 Type I: acute upper airway obstruction
- LARYNGOSPASM (causes 50% of cases in adults)
- epliglottitis/croup (causes 75% of cases in pediatric population)
- biting on endotracheal tube/LMA
- strangulation
- hematoma
- foreign body aspiration
- hiccups
- goiter
 Type II: occurs after relief of a chronic obstructive process
ex: laryngeal CA s/p surgery (except laryngectomy)
obstructive sleep apnea with correction
obstructive goiter undergoing thyroidectomy
Pathophysiology:
-> sudden high negative intrathoracic pressure, which causes fluid exudate to enter the
lungs
1. acute glottic closure -> patient continues to inspire against a closed glottis
2. high negative intrathoracic pressure -> increased venous return to right heart and
pulmonary arteries
3. volume expansion -> high arteriole/capillary fluid pressures -> transudation into
alveolar space
4. hypoxic vasoconstriction of pulmary and systemic arterioles -> Increased SBP
and afterload
5. hypoxia -> catecholamine release -> increased peripheral resisance
---> increased fluid volume within thoracic cavity and unbalanced transmembrane
pressures in alveoli
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Michelle Torres


1/7/09
Mortality rate varies from 10-40%
Most cases resolve within 24 hours, however some take several days to weeks.
Who is at risk?
 patients undergoing surgeries involving the upper aerodigestive tract (because
more likely than other procedures to cause laryngospasm secondary to laryngeal
irritation)
-> upper GI endoscopy
-> general otolaryngologic, nasal, and paranasal sinus surgery
 athletic men (because can generate higher intrathoracic pressures and maintain
periods of apnea longer)
Treatment?
 maintain airway
 supplemental O2
 gentle diuresis, fluid restriction
 continuous positive pressure ventilation or even intubation depending on the
severity
 monitored setting
 steroid use to lessen the pulmonary damage is controversial
How do you prevent it? (measures to prevent laryngeal stimulation)
 topical anesthesia on larynx prior to intubation in high risk groups
 IV lidocaine prior to extubation
 throat pack, careful oropharyngeal suctioning
 extubation in stage 1 anesthesia (not 2, when patients are more likely to go into
laryngospasm)
Differential diagnosis: aspiration pneumonia
What happened to the patient?
Patient was placed on 10L NRB, and sats improved to mid 90s. He was also given a dose
of lasix 10mg IV, with UOP of 1100cc in the PACU. Patient was titrated down to 5L
FM, and was able to maintain sats in the mid-90s. Later on that evening in the floor,
patient did not require any more oxygen supplementation, and he was satting in the mid90s. He was subsequently discharged the next day.
References:
Chuang YC, Wang CH, Lin YS. Negative pressure pulmonary edema: report of three cases and review of the literature. Eur Arch
Otorhinolaryngol. 2007 Sep;264(9):1113-6. Epub 2007 Jun 28.
Lang SA, Duncan PG, Shephard DA, Ha HC. Pulmonary oedema associated with airway obstruction. Can J Anaesth. 1990
Mar;37(2):210-8.
Westreich R, Sampson I, Shaari CM, Lawson W. Negative-pressure pulmonary edema after routine septorhinoplasty: discussion of
pathophysiology, treatment, and prevention. Arch Facial Plast Surg. 2006 Jan-Feb;8(1):8-15.
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