Treatment Interventions on Anesthesiology Board Exams

It is not a secret that the anesthesiology board exams test your knowledge regarding the details of numerous treatment interventions. Besides having the knowledge of the circumstances in which you have to choose a specific treatment intervention over another, it is also important to know the details regarding each particular intervention. Thus, the question arises “just how much detail regarding treatment interventions does the exam-taker need to know?”

In every field of medicine, there are certain treatment interventions that are administered by specific practitioners in that field or, in some cases, the patients are referred to specialists who can administer these interventions. For the purposes of board exams, the test-taker is assumed to be a general and average practitioner in a specialty. Keeping this in mind, what are you expected to know regarding treatment interventions that you are unlikely to administer yourself?

One yardstick to gauge the level of knowledge that you should have regarding a treatment intervention is to base it on the information that is required to obtain informed consent from a patient for that specific procedure. If a physician recommends a procedure to be performed, either as a component of the work-up or as a treatment intervention, and yet is not the one who is going to perform the procedure, it is still important to have adequate knowledge regarding the procedure so that the initial informed consent can be obtained from the patient. Here are some of the facts that the physician should know:

• The general concept behind the procedure. How does the procedure treat the condition or help establish a diagnosis? What are the effects of the intervention on the body?
• The benefits and risks of the procedure.
• The alternative procedures or interventions available, and the benefits as well as the risks of those alternatives.
• The pros and cons of no treatment at all.

Consider the following examples:

• It is important for a neurologist to have knowledge of the general procedures, indications, and the interpretation of the results of electromyographic studies, even if he or she is not going to perform the studies him/herself.
• A general surgeon who is not a specialist in breast cancer surgery should still have the knowledge regarding the general procedures, the benefits, and the risks of mastectomies versus lumpectomies for several different forms of breast cancer.
• An anesthesiologist who does not specialize in the management of anesthesia during lung transplantation should still have a basic knowledge of the procedure.

 

Example from Anesthesiology: The Management of Anesthesia during Lung Transplantation

On the anesthesiology boards, a general anesthesiologist is expected to know the following details regarding lung transplantation procedure:

• Indications for lung transplantation:
  • Cystic fibrosis
  • Chronic obstructive pulmonary disease (COPD)
  • Bronchiectasis
  • Idiopathic pulmonary fibrosis
  • Primary pulmonary hypertension
  • Eisenmenger syndrome
• General concepts of lung transplantation:
  • There are four principal approaches to lung transplantation: single-lung transplantation, bilateral sequential lung transplantation, heart-lung transplantation, and transplantation of lobes from living donors.
  • As compared to single-lung transplants, survival has been found to be generally better with double-lung transplantation.
  • Immunosuppression is started intraoperatively and is continued for life.
  • Lung transplantation can dramatically improve lung function in patients with end-stage lung disease. Peak improvement is achieved usually within 3-6 months.
  • The management of anesthesia during lung transplantation procedure follows the same principles that are used when a pneumonectomy is performed.
  • The trachea is intubated using a double-lumen endotracheal tube, and the proper placement of the tube is verified through fiberoptic bronchoscopy.
  • Anesthetic maintenance is based primarily on intravenous infusions due to the frequent need for airway access (bronchoscopy, suctioning), which leads to problems in maintaining stable levels of inspired anesthetic vapor.
  • There are no specific recommendations for drugs to be used for the induction and maintenance of anesthesia, nor skeletal muscle paralysis during lung transplantation.
  • Monitoring includes the placement of pulmonary artery and intraarterial catheters. The monitoring of pulmonary artery pressure is particularly important.
  • Transesophageal echocardiographic monitoring may be used for the evaluation of right and left ventricular function and fluid balance.
  • Cardiopulmonary bypass may be required if respiratory or cardiac instability develops during the procedure.
• Relative contraindications for lung transplantation:
  • Age more than 65 years
  • Unstable or critical clinical conditions such as mechanical ventilation, shock, extracorporeal membrane oxygenation
  • Colonization with highly virulent or resistant bacteria, mycobacteria, or fungi
  • Severely limited functional status along with poor rehabilitation potential
• Absolute contraindications for lung transplantation:
  • Active malignancy within the last two years; cancer is considered to be a contraindication due to the risk of recurrence of cancer with immunosuppression.
  • Untreatable advanced dysfunction of another major organ system, such as liver, heart, kidney.
  • Noncurable chronic extra-pulmonary infection
  • Significant spinal or chest wall deformity
  • Lack of a reliable or consistent social support system
  • Substance addiction which is either currently active, or was active during the last six months
• Potential complications and adverse effects
  • The intraoperative anesthetic complications primarily depend on the underlying lung disease. For instance, there is a risk of the development intraoperative hypotension in emphysema patients on induction from positive-pressure ventilation.
  • Hypoxia is a potential intraoperative problem, particularly during one-lung ventilation. PEEP to the dependent lung, CPAP to the nondependent lung, or some kind of differential lung ventilation may be required to minimize intrapulmonary shunting and hypoxia.
  • Bronchial dehiscence and respiratory failure resulting from sepsis or rejection are the principal causes of mortality associated with lung transplantation.
  • The normal cough reflexes from the lower airways are lost due to the denervation of the donor lung, and this predisposes the patient to develop pneumonia.
  • Mild transient pulmonary edema is commonly seen in a newly transplanted lung. However, in some patients, it is sufficiently severe to result in a form of acute respiratory failure, which is termed as primary graft failure.
  • The most common airway complication of lung transplantation is stenosis of the bronchial anastomosis. It typically occurs several weeks following transplantation.

This may seem to be a lot of information. However, if you are an anesthetist specialized in pulmonary diseases and lung transplantation, you are expected to have even more information regarding lung transplantation, as is exemplified by the following list. Knowledge about the following items, however, may not be required for a general anesthesiology board exam:

• A clam-shell thoracotomy is performed for bilateral or sequential lung transplantation, and a posterolateral thoracotomy for single-lung transplantation.
• During the transplant, the pulmonary artery catheter may need to be withdrawn from the native pulmonary artery, stapled, and re-floated into the pulmonary artery of the non-operative lung.
• Limiting the donor lung ischemic period to four hours is considered optimal.
• During the transplant procedure, right ventricular failure and severe pulmonary hypertension may occur when the pulmonary artery is clamped. Inhalation of nitric oxide or infusion of a pulmonary vasodilator, such as prostacyclin, may be beneficial in managing pulmonary hypertension in such a situation.
• During the procedure, drug-induced histamine release is not desirable, whereas, drug-induced bronchodilation is beneficial.

Sources:

Slinger PD, Campos JH. Anesthesia for Thoracic Surgery. In: Miller RD, Cohen NH, Eriksson LI, Fleisher LA, Wiener Kronish JP, Young WL, editors. Miller’s Anesthesia. 8th ed. Philadelphia, PA: Churchill Livingstone; 2015. pp. 1942-2006. Ch. 66.

Deshpande R, Kurup V. Restrictive Respiratory Diseases and Lung Transplantation. In: Hines RL, Marschall KE. Stoelting’s, editors. Anesthesia and Coexisting Disease. 7th ed. Philadelphia: Elsevier; 2018. pp. 33–52. Ch. 3.

 

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