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Clinical Cases: You’re scheduled to anesthetize a 70-year-old man for a carotid endarterectomy, a 50-year-old man for an arthroscopic rotator cuff repair, and a 30-year-old woman for an Achilles tendon repair. What anesthetics would you plan? “Keep It Simple, Stupid…” The KISS principle applies in anesthesiology, too.
Discussion: In 1960, U.S. Navy aircraft engineer Kelly Johnson coined the KISS Principle, an acronym for “Keep It Simple, Stupid.” The KISS principle supports that most systems work best if they are kept simple rather than made complex. Simplicity should be a key goal in design, and unnecessary complexity should be avoided. The KISS Principle likely found its origins in similar concepts such as Occam’s razor, Leonardo da Vinci‘s “Simplicity is the ultimate sophistication,” and architect Mies Van Der Rohe‘s “Less is more.”
Let’s look at the three cases listed above. For the carotid surgery, you choose an anesthetic regimen based on dual infusions of propofol and remifentanil, aiming for a rapid wake-up at the conclusion of surgery. For the arthroscopic rotator cuff repair, you fire up the ultrasound machine and insert an interscalene catheter preoperatively. After you’ve inserted the catheter, you induce general anesthesia with propofol and maintain general anesthesia with sevoflurane. For the Achilles repair, you perform a popliteal block preoperatively. After you’ve performed the block, you induce general anesthesia with propofol, insert an endotracheal tube, turn the patient prone, and maintain general anesthesia with sevoflurane and nitrous oxide.
All three cases proceed without complication.
Ten miles away, an anesthesiologist in private practice is scheduled to do the same three cases. For each of the three cases she chooses the same anesthetic regimen: Induction with propofol, insertion of an airway tube (an endotracheal tube for the carotid patient, and a laryngeal mask airway for the shoulder patient and the ACL patient, and an endotracheal tube for the prone Achilles repair), followed by sevoflurane and nitrous oxide for maintenance anesthesia and a narcotic such as fentanyl titrated in as needed for postoperative analgesia. The carotid patient is monitored with an arterial line, and vasoactive drugs are used as necessary to control hemodynamics.
“Wait a minute!” you say. “Elegant anesthesia requires advanced techniques for different surgeries. Why would a private practitioner do all three cases with nearly identical choices of drug regimen? Why would a private practitioner fail to tailor their anesthetic plan to the surgical specialty? Total intravenous anesthesia and ultrasound-guided regional anesthesia are important arrows in the quiver of a 21st-century anesthesiologist, aren’t they?”
In my first week in private practice, just months after graduating from the Stanford anesthesia residency program, the anesthesia chairman at my new hospital emphasized relying on the KISS Principle in anesthesia practice. He stressed that the objective of clinical anesthesia wasn’t to make cases interesting and challenging, but to have predictable and complication-free outcomes. Exposing a patient to extra equipment (two syringe pumps), or two anesthetics (regional plus general) instead of general anesthesia alone, adds layers of complexity, and defies the KISS principle.
There are no data indicating that using two syringe pumps and total intravenous anesthesia will produce a better outcome than turning on a sevoflurane vaporizer. There are no data demonstrating that combining a regional anesthetic with a general anesthetic for shoulder arthroscopy or Achilles tendon surgery will improve long-term outcome.
The KISS principle opines that most systems work best if they are kept simple rather than made complex, and doing two anesthetics instead of one adds complexity. I’ve learned that an anesthesiologist should choose the simplest technique that works for all three parties: the surgeon, the patient, and the anesthesiologist. The hierarchy from most simple to complex might look something like this: (1) local anesthesia alone, (2) local plus conscious sedation, (3) a regional block plus conscious sedation, (4) general anesthesia by mask, (5) general anesthesia with a laryngeal mask airway, (6) general anesthesia with an endotracheal tube, or (7) general anesthesia plus regional anesthesia combined. The combination of drugs used should be as minimal and simple as possible.
If all three parties (the surgeon, the patient, and the anesthesiologist) are okay with the patient being awake for a particular surgery, then the simplest of the first three options can be selected. If any one or all of the three parties wants the patient unconscious, then the simplest option of (4) – (7) can be selected.
I’m not an opponent of regional anesthesia. Ultrasound-guided regional anesthesia is a significant advance in our specialty for appropriate cases, and substituting regional anesthesia for a general anesthetic is a reasonable alternative. Compared with general anesthesia, peripheral nerve blocks for rotator cuff surgery have been associated with shorter discharge times, reduced need for narcotics, enhanced patient satisfaction, and fewer side effects (Hadzic A, Williams BA, Karaca PE, et al.: For outpatient rotator cuff surgery, nerve block anesthesia provides superior same-day recovery after general anesthesia. Anesthesiology 2005; 102:1001-1007). On the other hand, meta-analysis has demonstrated no long-term difference in outcome between regional and general anesthesia for ambulatory surgery. (Liu SS, Strodtbeck WM, Richman JM, Wu CL: A comparison of regional versus general anesthesia for ambulatory anesthesia: A meta-analysis of randomized controlled trials. Anesth Analg 2005; 101:1634-1642). Why perform combined regional anesthesia plus general anesthesia for minor surgeries? Are we doing regional blocks just to showcase our new ultrasound skills? If there is an ultrasound machine in the hallway and an ambulatory orthopedic patient on the schedule, these two facts alone are not an indication for a regional block. Patients receive an extra bill for the placement of an ultrasound-guided block, and economics alone should never be a motivation to place a nerve block.
In a painful major orthopedic surgery such as a total knee replacement or a total hip replacement, a regional block can improve patient comfort and outcome. This month’s issue of Anesthesiology a retrospective review of nearly 400,000 patients who had total knee or total hip replacement. Compared with general anesthesia, neuroaxial anesthesia is associated with an 80% lower 30-day mortality and a 30 – 80% lower risk of major complications (Memtsoudis et al., Perioperative Comparative Effectiveness of Anesthetic Technique in Orthopedic Patients, Anesthesiology. 118(5):1046-1058, May 2013).
Many outpatient orthopedic surgeries performed under straight general anesthesia require only modest oral analgesics afterward. I had general anesthesia for a shoulder arthroscopy and subacromial decompression last month, and required no narcotic analgesics post-op. If I’d had an interscalene block, the anesthesiologist could have attributed my comfort level to the placement of the block. No block was necessary.
Achilles repairs don’t require a combined regional–general anesthetic. Achilles repairs simply don’t hurt very much. One surgeon in our practice does his Achilles repairs under local anesthesia with the patient awake, and the cases go very smoothly. Other surgeons in our practice insist that a popliteal block be placed prior to general anesthesia for Achilles repairs, a dubious decision because (a) it defies the KISS Principle, and (b) the surgeon has no expertise in dictating anesthetic practice.
Every peripheral nerve block carries a small risk. Although serious complications are unusual, risks include falling; bleeding; local tissue injury, pneumothorax; nerve injury resulting in persistent pain, numbness, weakness or paralysis of the affected limb; or local anesthetic toxicity. Systemic local anesthetic toxicity occurs in 7.5–20 per 10,000 peripheral nerve blocks (Corman SL et al., Use of Lipid Emulsion to Reverse Local Anesthetic-Induced Toxicity, Ann Pharmacother 2007; 41(11):1873-1877).
Use the simplest anesthetic that works. Assess whether combined regional–general anesthetics are necessary or wise. I realize that complex anesthetic regimens are routine aspects of a solid training program, because residents need to leave their training program with a mastery of multiple skills. But once you’re in private practice, my advice is to take heed of the KISS Principle.
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Published in September 2017: The second edition of THE DOCTOR AND MR. DYLAN, Dr. Novak’s debut novel, a medical-legal mystery which blends the science and practice of anesthesiology with unforgettable characters, a page-turning plot, and the legacy of Nobel Prize winner Bob Dylan.
In this debut thriller, tragedies strike an anesthesiologist as he tries to start a new life with his son.
Dr. Nico Antone, an anesthesiologist at Stanford University, is married to Alexandra, a high-powered real estate agent obsessed with money. Their son, Johnny, an 11th-grader with immense potential, struggles to get the grades he’ll need to attend an Ivy League college. After a screaming match with Alexandra, Nico moves himself and Johnny from Palo Alto, California, to his frozen childhood home of Hibbing, Minnesota. The move should help Johnny improve his grades and thus seem more attractive to universities, but Nico loves the freedom from his wife, too. Hibbing also happens to be the hometown of music icon Bob Dylan. Joining the hospital staff, Nico runs afoul of a grouchy nurse anesthetist calling himself Bobby Dylan, who plays Dylan songs twice a week in a bar called Heaven’s Door. As Nico and Johnny settle in, their lives turn around; they even start dating the gorgeous mother/daughter pair of Lena and Echo Johnson. However, when Johnny accidentally impregnates Echo, the lives of the Hibbing transplants start to implode. In true page-turner fashion, first-time novelist Novak gets started by killing soulless Alexandra, which accelerates the downfall of his underdog protagonist now accused of murder. Dialogue is pitch-perfect, and the insults hurled between Nico and his wife are as hilarious as they are hurtful: “Are you my husband, Nico? Or my dependent?” The author’s medical expertise proves central to the plot, and there are a few grisly moments, as when “dark blood percolated” from a patient’s nostrils “like coffee grounds.” Bob Dylan details add quirkiness to what might otherwise be a chilly revenge tale; we’re told, for instance, that Dylan taught “every singer with a less-than-perfect voice…how to sneer and twist off syllables.” Courtroom scenes toward the end crackle with energy, though one scene involving a snowmobile ties up a certain plot thread too neatly. By the end, Nico has rolled with a great many punches.
Nuanced characterization and crafty details help this debut soar.
Click on the image below to reach the Amazon link to The Doctor and Mr. Dylan:
Learn more about Rick Novak’s fiction writing at ricknovak.com by clicking on the picture below: