Coughing during surgery can be dangerous and disruptive. It can increase bleeding, disrupt surgical sites, and even cause aneurysms or tears in surgical incisions. Controlling coughing is critical in the operating room, but is often challenging as many factors can trigger coughing in a surgical patient. This article will explore the causes of intraoperative coughing and proven techniques surgeons use to prevent coughing during surgery.
What causes coughing during surgery?
There are several potential triggers that can stimulate coughing during a surgical procedure:
Irritation of the vocal cords or windpipe
The insertion of a breathing tube, laryngoscope, or bronchoscope can directly stimulate the vocal cords and trachea, triggering the cough reflex. Even subtle movement of the tube during surgery can cause irritation.
Collection of mucus
Anesthesia slows the mucociliary escalator, causing mucus to build up in the airways. This triggers coughing as a protective reflex to clear the airways.
Blood or secretions in the airway
During surgery around the nose, mouth, or airway, small amounts of blood or surgical debris can trickle into the trachea. The cough reflex acts to expel these foreign particles.
Mechanical stimulation of the carina
The carina is the upside-down V shaped structure in the lower windpipe. When a breathing tube or bronchoscope bumps against the carina, it can stimulate coughing.
Light anesthesia
If anesthesia is too light, airway reflexes like coughing remain partially active. Sufficient anesthesia is required to suppress the cough reflex.
Emergence from anesthesia
As anesthesia wears off and protective airway reflexes return, coughing helps clear any residual mucus or secretions.
Risks of coughing during surgery
Coughing creates spikes in blood pressure and intracranial pressure. This risks major complications:
- Increased bleeding at the surgical site or incisions
- Disruption of delicate surgery around nerves or organs
- Tears along staple lines after lung surgery
- Rupture of aneurysms or arterial grafts
- Dehiscence (reopening) of surgical incisions
- Regurgitation and aspiration in laparoscopic surgeries
By raising pressures inside blood vessels or wounds, forceful coughing can undo careful surgical repairs or sutures. This delays healing after surgery.
Techniques to suppress coughing during surgery
Here are proven techniques anesthesiologists use to prevent coughing in the operating room:
Adequate anesthesia depth
Ensuring a proper plane of general anesthesia prevents unwanted reflexes. Anesthetic depth is carefully monitored and adjusted to suppress coughing.
Smooth airway instrumentation
Gentle handling of the airway during intubation or bronchoscopy prevents stimulating the cough reflex. Anesthesiologists use plenty of lubrication on instruments.
Cuff inflation on the breathing tube
Once the breathing tube is positioned in the windpipe, the cuff is inflated. This seals the airway and blocks irritating leaks that could trigger coughing.
Medications to suppress the cough reflex
Cough-suppressing drugs are often given before anesthesia, including lidocaine, opioids like fentanyl, or bronchodilators like albuterol.
Humidification and warming of breathing gases
Warm, humidified airflow is less irritating than cool dry gases. This reduces coughing triggered by medical gases.
Suctioning prior to emergence
Before waking from anesthesia, any residual mucus is cleared from the airway using suction. This prevents coughing from mucus buildup.
Smooth emergence from anesthesia
The anesthesiologist carefully lightens anesthesia at the end of surgery to maintain suppression of reflexes like coughing as long as possible.
Medications to suppress coughing
Here are specific medications anesthesiologists administer to prevent coughing:
Lidocaine
Lidocaine is a local anesthetic that numbs the airway. It can be sprayed into the throat before intubation or administered intravenously. Lidocaine suppresses the urge to cough.
Opioids
Intravenous opioids like fentanyl, morphine, or hydromorphone suppress the cough reflex center in the brain. However, opioids can also suppress breathing and must be used judiciously.
Propofol
The intravenous anesthetic propofol depresses airway reflexes including the cough reflex. A propofol infusion during surgery helps prevent coughing.
Bronchodilators
Albuterol relaxes smooth muscle in the airways, which discourages coughing triggered by bronchoconstriction. Other bronchodilators like aminophylline may also be used.
Steroids
Steroids like dexamethasone reduce airway inflammation and sensitivity. This makes coughing less likely during procedures like bronchoscopy or laryngoscopy.
Antihistamines
Medications like diphenhydramine or hydroxyzine help dry secretions and reduce triggers like post-nasal drip that could stimulate coughing.
Anesthesia techniques to reduce coughing
Beyond medications, anesthesiologists use these techniques to prevent coughing:
Topical anesthesia
Local anesthetics like lidocaine are sprayed into the mouth and throat before instrumentation. This numbs irritating sensations.
Tube exchanger
A tube exchanger is a hollow catheter used to guide the breathing tube without stimulating the airway during intubation.
Smaller diameter tubes
Using smaller breathing tubes in children or slender adults reduces irritation of the trachea and larynx.
Video laryngoscopy
Video or fiberoptic intubation allows visualization of the airway. This results in smoother intubation with less tissue trauma.
Awake intubation
With an awake technique, the patient’s cough reflex remains active to protect the airway. This may be preferable in some surgeries.
Steps to prevent coughing during emergence
As anesthesia wears off after surgery, anesthesiologists take steps to maintain suppression of coughing:
Wait for return of airway reflexes
No coughing can occur until protective reflexes like gag and swallow return. Extubation is delayed until these reflexes resume.
Clear secretions before waking
Any mucus or blood is suctioned from the mouth and windpipe before discontinuing anesthesia.
Deflate the breathing tube cuff gradually
This allows the vocal cords to gradually regain function and avoids a sudden stimulation.
Leave the breathing tube in place during coughing
The tube remains positioned until coughing subsides to prevent aspiration.
Administer more medications
Additional opioids or lidocaine may be given right before extubation to cover the transition off the ventilator.
Treatment options for coughing after surgery
If coughing still occurs after extubation, here are options to control it:
Racemic epinephrine
This medication combines a bronchodilator with a decongestant to reduce airway irritation and swelling.
Aerosolized lidocaine
Lidocaine is nebulized into the lungs as a local anesthetic to numb the cough reflex center.
Helium-oxygen mixtures
Breathing helium-based gases can reduce the irritation of coughing. The low density of heliox prevents turbulence.
Humidified oxygen
Moist oxygen soothes irritated airways. This may discourage continued coughing after surgery.
Medicated throat lozenges
Anesthetic lozenges with benzocaine or other cough suppressants can temporarily numb the throat.
Nebulized opioids
Opioids like fentanyl are nebulized and inhaled for additional cough suppression in the post-operative period.
Preventing coughing in high-risk patients
Certain patients are at increased risk for problematic coughing during surgery:
Smokers
Chronic irritation makes smokers prone to coughing when instruments touch the trachea. Smoking cessation before surgery is recommended.
Children
Young children have very sensitive airway reflexes that must be adequately blunted with anesthesia.
Respiratory infection
Coughing is more easily triggered when the airways are already inflamed by a cold or pneumonia. Elective surgery may be postponed.
Asthma
Hyperreactive airways in asthmatics are prone to coughing episodes. Extra medications are needed to control their airway hypersensitivity.
COPD
Patients with chronic bronchitis have excess mucus and cough easily with airway instrumentation. Their lungs are pretreated with bronchodilators.
Suspected difficult intubation
Risk factors for difficult intubation include facial trauma, obesity, and abnormal anatomy. Awake fiberoptic intubation may be safer.
Conclusion
Coughing during surgery can have catastrophic consequences but is preventable with the right techniques. Skilled anesthesiologists use optimal anesthesia depth, smooth airway handling, cough-suppressing medications, and vigilance during transitions to avoid stimulating this dangerous reflex during surgery. With proper precautions, the urge to cough can be suppressed until the patient is safely recovered after surgery.
