decreased spo2 after endotracheal intubation: a case report by r2 彭育仁

Decreased SpO2 after Decreased SpO2 after endotracheal intubation: a endotracheal intubation: a

case reportcase report

By R2 彭育仁

Brief historyBrief history

This 23-year-old lady had IDDM, hypertension and gout without regular medications. She came to our ER on 6/15 due to fever for 2 days and RUQ pain for one day. Acute appendicitis was impressed and operation was delayed to 7:30 AM on 6/16 due to her NPO since 9PM on 6/15. She gave no history of cough, respiratory infection, bronchitis or asthma.


PE:

slight obesity (BH 152cm, BW 70kg)

T/P/R/BP normal except mild fever

SpO2 : 99% under room air without dyspnia

RUQ pain with rebound tenderness

Lab: leukocytosis with left shift

CXR: no active lesion, reduced lung volume


Induction of anesthesia was accomplished with IV fentanyl 100ug, atropine 0.7mg, thiopental 250mg and succinylcholine 80mg. After ventilation with 100% O2 by face mask, direct laryngoscopy was performed with No.3 Machintosh blade but no epiglottis was seen. Due to decrease of SpO2, she was ventilated again with mask. After adjusting her posion and changing to No.4 blade, direct laryngoscopy was retried and some blood was seen in the field.

Brief historyBrief history Gr II to III view of larynx was noted and the trachea

was intubated with an 7-mm cuffed tube with stylet smoothly. No bucking, coughing or vimiting was noted. Chest wall rise and fall with ventilation and capnogram showed CO2 excretion waveform. No breath sound was heard over stomach but breath sound on chest showed bilateral rhonchi without crackle. SpO2 was around 85% despite ventilation with 100% O2 for 5 minutes. Cuff rupture was noted due to inability to inflate the pilot balloon. ET tube was replaced with a new one by tube changer smoothly.


SpO2 increased slowly and kept constant around 90% (ABG showed PaO2 79) and ever dropped to 72%.Airway resistance was around 30 cmH2O. Immediately after intubation a small amount of blood drained from ET tube. Suction was applied and 10ml blood was sucked out. A fibreoptic bronchoscopy via ET tube showed moderate blood in the trachea and blood obstructed 1/3 to 1/2 area of bilateral main bronchus.


No active bleeder was noted and trachea laceration was impressed. No crepitus was noted over neck and only supportive treatment was given.

SpO2 kept around 94% during the operation. During the emergence, the saturation decreased when using room air and ventilating by herself. She was then admitted to ICU without extubation.


In ICU, CXR showed no local patchy densities. She extubated ET tube by herself and SpO2 dropped to 90%.

The post-op course was smooth and she was transferred to general ward on the next day and discharged on 6/21.

Tracheal lacerationTracheal laceration

Tracheal laceration is a rare complication of endotracheal intubation, which usually occurs during the act of intubation or as a result of an immediate complication once the tube is in place.

S/S: hemoptysis, subcutaneous and mediastinal emphysema, dyspnea, cyanosis, tension pneumothorax

Tracheal laceraionTracheal laceraion

Risk factors:

preeaxisting pathology or malformation of the airway, use of sharp protuberan stylets, repeated of forceful attempts at intubation (difficulty), over-inflation of the ET tube cuff, bucking or coughing or violent movements, increase in airway pressure caused by a closed expiratory valve or opening the oxygen-flush valve, rigid bronchoscopy, elderly and chlid……


Pathophysiology:

Tracheal laceration usually occurs posteriorly because the posterior wall is membranous and unsupported by cartilagenous rings. If rupture occurs, air enters the fascial plane and dissects cephalad into the mediastinum and neck or caudad and subcutaneous emphysema happened.


Diagnosis:

Clinical presentation and direct vision (bronchoscope or thoracotomy)

Management:

Surgical repair of large laceration is necesssary. Find clues of pneumothorax and then use chest tubes. If air leak is large, reduction of airway pressure and use of 100% O2 is necessary.

DiscussionDiscussion

Confirmation of tracheal intubation is the first priority when saturation decrease:

Auscultation of breath sound, one lung ventilation, capnography, direct visulization, reservoir bag compliance, tube condensation of water vapor…..In this patient , the ET tube is in its proper position.


The clinical presentation of this patient is difficulties in intubation, hemoptysis, moderate blood in tracheal lumen. No subcutaneous emphysema or pneumothorax was noted.

Aspiration can be ruled out due to no vomiting was noted and no vomitus was seen by bronchoscope.


The etiology of tracheal laceration in this patient might be due to intubation difficulty, stylet use, her fragile tissue….and so on. Tube changer and replacement of ET tube might also be a contruibutor. There is no question that intubation should be blamed for this injury.

The etiology of cuff rupture was a mystery.

(already broken, tear during intubation, inflat too much and break….)


The rapid decrease in saturation can be attributed to the occupation of airway lumen by blood on her decreased lung volume. Breath sound showed rhonchi (large airway) without rales and aspiration pneumonitis or pulmonary edema can be ruled out and confirmed by CXR later.


Any methods that can remove blood in airway can improve the situation such as suction, Trendelenberg or lateral decubitus position.

PEEP should be avoided to increase airway pressure that may aggravate the condition and can be lethal.

Prompt recognition with immediate and accurate diagnosis and management are necessary before irreversible cerebral damage has occurred.

ReferenceReference

1.Pulmonary complications following endotracheal intubation. Intensive care medicine 11(4) 223-5 1985

2. Surgical emphysema, bilateral pneumothorax, pneumomediastinum and pneumoperitoneum complicating intubation for anaestehsia. Postgraduate medical journal 51(599):654-6, 1975 Sep

3. Mainstem bronchial rupture during general anestehsia. A&A 58(1):59-61,1979 Jan-Feb

4. Tracheal laceration with massive subcutaneous emphysema: a rare complication of endotracheal intubation. Thorax 34(5):665-9,1979 Oct

5. Rupture of trachea following endotracheal intubation. JAMA 204(11):995-7, 1968 Jun10

decreased spo2 after endotracheal intubation: a case report by r2 彭育仁

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