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50-Year-Old Male Scheduled for Video-Assisted Thoracoscopic Discectomy and Spinal Fusion - 2008-04-09
Moderator - T. Deborah Montemurno, M.D.
Co-moderator - Gabor Simon, M.D.
Objectives:
After preparing for and discussing this case, participants will be expected to:
1. Discuss the preoperative workup of thoracoscopic surgery.
2. Understand the physiology and potential complications of one-lung-ventilation.
3. Discuss the anesthetic management for thoracoscopic surgery.
4. Discuss the pathophysiology of prolonged one-lung-ventilation and re-expansion pulmonary edema.
Case: 50-year-old man with several months history of intermittent left sided thoracic and chest pain. He presents to a neurosurgeon for assessment. He is found to have no sensory or motor deficits. He describes his pain as severe, intractable intermittent pain of the mid-back and left chest in posterior/mid-axillary/anterior distribution. It is not relieved by common over the counter medicines. He did experience some relief with percocet, but does not take it secondary to its side effects.
PMH: denies
PSH: none
Meds: none
All: NKDA
SH: no tobacco history, no illicit drug use, does drink socially
MRI revealed T5-6 herniated disc with ventral cord compression and left foraminal encroachment. He is started on decadron with pepcid for GI prophylaxis and booked for a R video-assisted thoracoscopic surgery with T5-6 partial laminectomy, discectomy. He presents to you for pre-operative surgical testing.
Preoperative Evaluation
In general, the preoperative assessment is important in determining the answer to three questions: 1) is this patient in optimal health? 2) is improvement necessary in this patient’s medical condition(s) prior to continuation on to surgery and 3) are there any health problems or medications that may influence perioperative events?
To that end, it is important to obtain a full medical history and physical. This should include the history of present illness and any therapy underway, medications, alcohol and tobacco history, airway exam and anesthesia history, cardiovascular and pulmonary examination. It is necessary to determine cardiac reserve… the maximum he/she can walk, number of flights without stopping, ejection fraction, ability to perform at least 4 METs (equivalent of 5 blocks or 2 flights of stairs at a reasonable pace without stopping). It is also important to elicit if there is a history consistent with a diagnosis of sleep apnea (“do you snore?”, “do you fall asleep in the daytime?”, weight gain – a 10% weight gain is associated with a 30% increase in number of apneic episodes). For the purposes of thoracic surgery, special attention must be paid to both cardiovascular and pulmonary function. A preoperative chest roentgenogram will provide a clinical marker for clinically severe pulmonary disease – hyperinflation is associated with a 33% increased rate of significant post-operative pulmonary complications. Pulmonary function tests provide information regarding likelihood of postoperative pulmonary complications. Who should have PFT’s? The Tisi guidelines state the criteria are the following: age>70, morbid obesity, thoracic surgery, upper abdominal surgery, smoking history, pulmonary disease. A stricter set of guidelines was recommended by the American College of Physicians to prevent unnecessary preoperative PFTs: lung resection surgery, smoking history with dyspnea, cardiac surgery, upper or lower abdominal surgery, pulmonary symptoms. In general, the presence of preexisting lung dysfunction is a major factor associated with postoperative pulmonary problems. Also important, however, is the incisional site and size, as well as surgical trauma to the lung. For chest surgery, a room air arterial blood gas analysis and simple spirometry (FEV1, FVC, FEV1/FVC ratio, peak flow, FEF 25-75%) is all that is recommended. If there are any abnormalities, then further testing may be recommended, such as split lung function studies to determine the percentage of pulmonary arterial blood flow to each lung.
The patient’s preoperative work-up revealed normal PFT’s. ECG was NSR at 65 with no ST/T changes, normal axis and no Q waves. All lab values, including coagulation profile, LFT’s, metabolic panel and CBC are normal. He has excellent exercise tolerance, which includes >5 flights with no SOB/CP and he actively exercises 3-5 days/week (jogging, swimming, cycling).
He presents on the morning of surgery having been NPO past midnight except for a sip of water with his medicines.
1. What is your anesthetic plan for this patient?
2. Is a thoracic epidural indicated?
3. Do you feel that invasive monitoring is necessary?
If so, what specifically and why?
4. Would your plan be altered knowing that this is the
first time the neurosurgical team is attempting
this approach to the planned surgery?
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