anesthesia 5th year, 10th lecture (dr. aamir)

Post operative complications

1. Upper airway obstruction2. Arterial hypoxemia3. Hypoventilation4. Hypotension5. Hypertension6. Cardiac dysrthymia7. Oliguria8. Bleeding9. Decreased body temperature10.Agitation (emergence delirium)11.Delayed awakening12.Nausea and vomiting13.Pain

Upper airway obstruction

1. Occlusion of the pharynx by the tongue.

2. Laryngeal obstruction

• Laryngospasm

• Laryngoedema

Signs and symptoms:

• Flaring of the nares

• Retraction at the suprasternal notch (tracheal tug)

• Retraction of intercostal and subcostal spaces

• Vigorous diaphragmatic and abdominal contractions

Treatment:

• Elimination upper airway obstruction due to occlusion of the pharynx by the tongue, by head tilt-jaw thrust method, this maneuver stretches muscles attached to the tongue serving to pull the tongue away from the posterior pharyngeal wall.

• If not beneficial a nasopharyngeal or oropharyngeal airway can be inserted (the nasopharyngeal airway is better tolerated by patients awakening from general anesthesia

Laryngospasm• In complete laryngospasm treated by extension

of the head and anterior displacement of the mandible plus application of positive airway pressure with bag and mask delivering pure oxygen.

• Complete laryngospasm that persist despite these maneuvers should be treated by IV succinylcholine, laryngoscopy and intubation of the trachea with cuffed tube. If intubation was impossible do cricothyrotomy which will provide temporary oxygenation until tracheostomy can be performed.

Laryngeal odema treated by:

• Humidifying the inhaled gases

• Administering nebulized epinephrine

• Dexamethasone ??

Arterial hypoxemia(PaO2<60mmHg)

Factors leads to post operative arterial hypoxemia:

1. Right-to-left intrapulmonary shunt (atelectasis)2. Mismatch of ventilation to perfusion 3. Decreased cardiac output4. Alveolar hypoventilation (residual effects of

anesthetics and/or muscle relaxants)5. Inhalation of gastric contents (aspiration)6. Pulmonary embolism7. Pulmonary edema

Pneumothorax

Posthyperventilation hypoxia

Increased oxygen consumption (shivering)

Advanced age

Obesity

Smoking

Lung disease

Diagnosis:

1. Clinical (cardiac dysrthmias, agitation, cyanosis)

2. Pulseoximeter (arterial hemoglobin oxygen saturation)

3. Measurement blood gas (PaO2<60mmHg)

Treatment:1. Oxygen supplementation2. Eliminate the cause of hypoxia:• If due to residual effects of muscle relaxants

(may be not enough dose of neostigmine given)

• If due to residual effect of opioids give naloxone

• If due to pneumothorax insert chest tube (if circulatory depression accompanies a tension pneumothorax, emergency treatment is placement a 12-14 gauge needle into the 2nd anterior intercostal space

• If oxygenation alone was not benefit incubate at once and put the patient on ventilator

Hypoventilation

Factors leading to postoperative hypoventilation1. Drug induced CNS depression (volatile

anesthesia, opioids)2. Residual effects of muscle relaxants3. Suboptimal ventilatory muscle mechanics

(patient position, obesity, gastric dilation, site of surgical incision)

4. Increased production of CO2 (hyperthermia)5. Co-existing chronic obstructive pulmonary

disease

Diagnosis:

• Clinical (signs of CO2 retention such as tachycardia, hypertension)

• Capnograph (PaCO2>45mmHg)

• Blood gas measurement (PaCO2>45mmHg)

Treatment:

• Clear airway and ventilate the patient

• If due to residual effect of opioids give naloxone

• If due to residual effects of muscle relaxants (not enough dose of neostigmine, succinylcholine apnea, myasthenia gravis, any potentiation of Nondepolarizing muscle relaxants like ABs, Mg, respiratory acidosis, hypokalemia----etc. Treat accordingly)

Thank you