Anesthesia in Patients With Pleural Disease - An Insight

Introduction:

Patients with an existing respiratory disease have a higher risk of developing complications around the time of surgery. In order to reduce the risks of complications, it is important to identify such patients and do a proper preoperative assessment. The complications occur mostly after the surgery. So, a patient is taken up for surgery only after they are eligible for the procedure.

What Is a Pleural Disease?

A disease that affects the pleura (tissue lining the outer and inner surfaces of the lungs) and other parts of the respiratory system is called pleural disease. The list of the diseases are:

• Asthma.

• Chronic obstructive pulmonary disease.

• Pneumonia.

• Pulmonary fibrosis.

• Pleural effusion.

• Hemothorax.

• Pleurisy.

• Empyema.

• Pneumothorax.

What Are the General Considerations for Anesthesia?

1. General Health Status:

• The ASA (American Society Association) classification determines a patient's fitness for surgery and ability to tolerate anesthesia. The same classification can be used to determine if lung disease patients are likely to have complications.

2. Smoking:

• The risk of complications is higher during surgery in patients with a smoking habit since their airways are very reactive and there is poor secretion clearance. To avoid this, the patient should abstain from smoking for eight weeks. It applies to both active and passive smokers.

3. Body Weight:

• Patients with a BMI of more than 35 are considered morbidly obese. It is not easy to intubate them to administer anesthesia. The perioperative (during the surgery) risk is higher because there is a chance of collapse of the lower part of the lungs, which may cause a decrease in the amount of blood supply to the lungs after the surgery. Weight should be reduced, and blood sugar levels and blood pressure should be controlled as preventive measures.

4. Physiotherapy:

• Patients are instructed to perform deep breathing exercises before surgery to increase lung volume, and techniques such as lying down can facilitate the early mobilization of airway secretions, known as postural drainage, lowering postoperative risks.

5. Pain Management:

• Pain should be managed to make coughing and deep breathing easier for the patient. Doing so helps prevent secretion retention, lung collapse, and postoperative pneumonia. Epidural anesthesia given through the spinal cord is effective.

What Are the Anesthetics Used in Pleural Disease?

• Thiopentone.

• Propofol.

• Ketamine.

• Halothane.

What Are the Different Techniques in Anesthesia?

• Before the surgery, the oxygen saturation level in the blood is measured with a pulse oximeter, and the level should be maintained throughout the surgery. Continuous monitoring can be done by blood gas analysis using an arterial catheter.

• During the surgery, the patient's breathing rate, pattern, and pulse rate should be continuously monitored using a pulse oximeter, an electrocardiogram, and blood pressure values.

The different routes and methods of anesthesia are:

• Local Anesthesia: This technique is beneficial in avoiding complications due to general anesthesia. However, it is only effective for a limited time and cannot be used for lengthy surgeries.

• Spinal Anesthesia: Anesthesia given through the spinal cord affects the muscles that help in breathing, increases the risk of lung collapse, and reduces the blood supply to the lungs when given at a higher place. When lower spinal anesthesia is given, there is a lesser chance of complications. For the spinal anesthesia technique, the patient should be able to lie in a flat position for a longer period.

• Ketamine Anesthesia: This anesthetic drug does not depress the cough or other respiratory reflexes. Hence, breathing is maintained better. But there is increased salivation, for which Atropine drug has to be used, which reduces salivation. Hence, Ketamine has to be used along with Atropine. It is mostly used in surgeries of the face and limbs.

• Controlled Anesthesia: Intubation through the trachea is done to secure the airway right before surgery to the head, neck, nose, and throat because access to the airway is restricted once the procedure is started. Airway access is difficult if the surgery is done with the patient lying on their belly. In such situations, endotracheal intubation and controlled anesthesia are useful.

• Spontaneous Anesthesia: It is given through a facemask so that any instrument does not touch the trachea, and the secretions induced by instruments are avoided. It is used in minor surgeries in a short period (less than two hours). A laryngeal mask is an even better option.

What Is the Preoperative Preparation of a Patient?

• General Examination: A history of cough, wheezing, mucus secretions or blood while coughing, chest pain, shortness of breath, and exercise tolerance (the amount of exercise done without tiring) is taken. The medication currently taken by the patient is noted. Allergies, if present, are noted. Also, previous records of anesthesia can help in planning the surgery.

• Clinical Examination: The respiratory rate, chest wall movement, cough, and sputum color are checked. The breath sounds are checked with a stethoscope. The chest is pounded all around.

• Investigations: Pulmonary (lung) function tests are done and correlated to the patient's age, sex, and weight. Blood tests are done to determine the presence of any infection. Other tests like arterial blood gases, oxygen concentration, and carbon dioxide concentration in the blood are measured.

• Preanesthetic Medication: In patients with compromised respiratory function, the drug given as premedication should not slow down respiration. Anticholinergic drugs like Atropine can be used when Ketamine is used to help clear the airway from secretions. Humidified oxygen is supplied through a cannula or masks to prevent postoperative hypoxia. Opioids and benzodiazepines are used with caution and only if necessary.

What Is the Postoperative Preparation of a Patient?

Postoperative care is crucial in patients with poor lung function, especially smokers, and in the abdomen and thoracic surgeries. The patient is continuously monitored for oxygen concentration in blood and fluid balance, and the neuromuscular paralysis should be reversed.

The following are some of the postoperative measures taken:

• Oxygen therapy.

• Pain management.

• Physiotherapy (breathing exercises).

• Administration of steroids.

• Adequate nutrition.

What Are the Postoperative Respiratory Problems?

The breathing should return to normal after the surgery by ensuring a patent airway. A patient might find breathing difficult due to pain, fear, higher levels of carbon dioxide in the blood, and anemia caused by bleeding. A proper recovery from anesthesia treatment is essential to avoid postoperative complications, which can lead to other complications such as:

• Stridor.

• Bronchospasm.

• Pneumonia.

• Pneumothorax.

• Pulmonary edema.

• Pulmonary embolism.

Conclusion

Surgeries done in the thoracic and upper abdominal regions are more often associated with pulmonary complications. It is estimated to be around 10 percent to 40 percent. Therefore, proper preparation of a patient's respiration function is mandatory during elective surgery. Patients with impaired lung function should be cleared for surgery after all the routine investigations meet the required criteria. And appropriate preoperative, perioperative, and postoperative measures should be taken to lower the risks of complications.