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Patient Safety Scenario #16: Getting to 6 Sigma by Eliminating Variation
Captain Rick Saber at the controls.

This essay is the 16th installment of the monthly Patient Safety essays, produced by the Patient Safety Subcommittee of the Ethics and Professionalism Committee. The essays are written in the spirit of the aviation industry’s “Black Box Thinking”, that is, in order improve our safety record, we need to think of errors not as incidences of bad people making bad mistakes, but as incidents where poor processes lead to errors, and are lessons to be learned from. To read earlier essays and learn how to contribute, please click here.

David Nelson, MD Chair, Patient Safety Subcommittee
Scott Lifchez, MD Co-Chair, Ethics and Professionalism Committee
Julie Adams, MD Co-Chair, Ethics and Professionalism Committee


(Most of the scenarios in this series are actual occurrences in the OR, this one is obviously either a concatenation of actual occurrences or the worst day anyone ever had in the OR.)

The surgeon arrives in the operating room, in plenty of time and ready to have a great day. The first patient has bilateral 3rd trigger finger releases scheduled. The case could not be simpler, so with any luck it should go smoothly and start the day off on the right note.

When the surgeon checks the room assignment board, they find that a new scheduler has assigned the case to the room in which the Intuitive Surgical da Vinci robot is used. The robot and the control unit cannot be moved out of the room for calibration reasons, and they take up a lot of space. This will make it difficult to do a case in which bilateral hands are operated upon since two hand tables, one set up on each side of the patient, will be used. The surgeon considers the problem but believes that they should be able to manage it, and decides to go ahead in the da Vinci room. As the surgeon enters the room, the surgeon notices that there is only one hand table in the room. The nurse in the room is new, and when asked, replies that he does not know if they have two hand tables. The surgeon muses that this case was scheduled as a bilateral case, that we do this all the time, and of course we have two hand tables. The surgeon goes out and finds one of the experienced nurses, only to find that the vascular surgeon is using one of the two hand tables to do a forearm shunt. They will have to use one hand table for one side of the bilateral trigger finger release and two arm boards for the other. When the surgeon goes in to see the patient, the preop nurse, who was just rotated down today from the floor because of a shortage of preop nurses, tells the surgeon that the anesthesiologist has already seen the patient and everything is set. The surgeon does not recognize the anesthesiologist’s name, and figures it must be someone who is new to the service. The preop nurse tells the surgeon that she cannot find the informed consent, so the surgeon will have to fill out another one, and the transfusion form has not been signed either. The surgeon explains that transfusions are not done for trigger finger cases, and the transfusion form does not need to be filled out. The preop nurse says she will check with someone else and verify that. Unfortunately, she also does not know where the consent forms are kept. The surgeon starts looking for the form as the preop nurse looks for her supervisor. The form is finally found, it is agreed that transfusion forms do not need to be filled out for a trigger finger, and the surgeon signs the consent form and the site. The patient is cleared to go to the room. At this moment, the surgeon’s pager goes off and the head nurse asks the surgeon to run up to the floor to sign a discharge paper or the patient cannot go home. The floor is full, the head nurse explains, and two surgeries in the preop area cannot start until the floor is sure some patients will be discharged. When the surgeon gets back to the room, the patient is in the room and asleep. Who did the timeout? the surgeon wonders. This question goes unanswered as the surgeon notes that the patient has an endotracheal tube in. This is a problem, since the surgeon normally does the case under a wide-awake local anesthesia no tourniquet (WALANT) protocol, so the patient can flex and extend the finger after the procedure is done, to verify that the release was complete. The new anesthesiologist did not know that, never spoke to the surgeon, and due to some medical problems felt more comfortable with an endotracheal tube. In any case, and with all the chaos, the surgeon forgot to do the block in the preanesthesia room, and now that the case is ready to start, it is too late to place the block and get the hemostasis that is needed for WALANT case anyway. The surgeon goes out to scrub, and when they come back in, the scrub tech gloves them with the wrong glove size. The scrub tech is not used to working with the surgeon, and was too busy to read the preference card. A bit more time is lost as the circulator gets the correct size gloves, size 8. However, the gloves are not latex free, and the surgeon has been getting skin irritation from using latex gloves. The circulator explains that someone forgot to order the latex-free ones and they are almost out of the surgeon’s size. She gives the scrub tech the last remaining size 8 latex-free glove, and the surgeon gloves up. As the prep is started on one hand, the surgeon asks where is the 2nd person who is supposed to prep the opposite hand. The circulator said they did not know they needed a 2nd person, and they thought they could do just one hand at a time. The surgeon pointed out that the normal protocol is to prep and drape both hands at the same time, which decreases overall OR time. No one is available to prep the second hand, so the circulator preps out one hand and drapes it, and then preps the other hand. However, the scrub tech, in trying to lay the 2nd drape, gets the drape contaminated, and in trying to straighten things out, the surgeon’s hands are contaminated. As the gloves are pulled off, the team recognizes that that was the last pair of latex-free gloves. As the circulator starts looking to see if there are any other latex-free gloves in the hospital, the surgeon talks the anesthesiologist about why he needs the patient to flex and extend to prove a complete release was done. As they are talking, the scrub tech tries to move the instrument table to the correct side. However, the room is so small that the instrument table gets contaminated when something falls onto the table. The surgeon considers whether or not a new instrument set is needed, or can they drape out that part of the table. The case has not even started! And the surgeon begins to consider whether it is even worth continuing doing surgery this day…

Something similar to this has certainly happened to all of us, but hopefully not all in one case: a new nurse, a new surgical assistant, a new surgery scheduler, a new central supply clerk. All it takes is for any person within the OR structure who is new to their job, and something that normally occurs without you having to pay any attention to it, goes wrong. Your attention is constantly diverted from concentrating on the specific case in front of you, and the potential for things going wrong escalates, as does your blood pressure.


Standard deviation, symbolized by sigma, σ, is the square root of the variance. 95% of occurrences will be within 2 σ above or below the mean. In high reliability organizations such as surgery, getting the right answer only 95% of the time is not acceptable. “Six Sigma” is a problem-solving methodology that enhances organizational operations. It can be defined in a number of ways, but one way is that is a methodology that results in a quality level of 3.4 defects per million opportunities, or one error in 6 σ occurrences above and below the mean. This is also called the “Five Nines” standard, since a 6 Sigma method should result in success 99.99966% of the time. Many industries such as the aviation industry and the nuclear power industry use the 6 Sigma methodology in planning their processes. One of the principles of 6 Sigma is decreasing variation.

If you examine your own day, you will see how mistakes occur when there are variations in your routine. You forgot your cell phone at home because your hands were occupied carrying the laundry that has to go to the cleaners. You forgot to call the patient back last night because your child was vomiting. The list goes on. Not only does variation in your personal life sow the seeds of error, errors increase more so in the complex environment of the operating room.

The goal in designing high reliability processes, such as those found in aviation or the operating room, is to decrease variation as much as possible so that everyone knows the routine, has done their task many times before, and can remember all the details that the task needs to be done correctly. As a practical matter, in the operating room we rarely control many of the sources of variation: who gets assigned to the room, what room you get assigned to, the time or day of the week the emergency case has to get done, etc. However, you should attempt to control the variation that you can control, and teach the staff why elimination of variation is a goal. Your team needs to understand the reason why you want it done the same way every time: it is not that you are a rigid control freak, it is because elimination of variation is a goal of all high reliability teams.

The American Academy of Orthopedic Surgery understands that control of variation is important for patient safety. One tool that the AAOS has recommended in order to control variation is a checklist. Their position paper is available online here:

It is fairly simple to design a checklist for use in the office to make sure your staff has done everything properly in preparation for the case such as obtaining the history and physical, making sure that the labs and the EKG got entered into the record, the equipment rep was notified, etc., and another checklist to be sure that you have checked everything before you leave the office for the OR.

Recognize that the addition of any new member to the team has the potential of introducing variability.  The new member will need more direct communication than veteran members of the team. Don’t wait for the first problem to occur, be proactive. It would be ideal to greet the new member and welcome them to the team, discuss the case and their role in each phase of the case. As the case proceeds, attempt to anticipate the challenges that the new member might face.

Elimination of variation has been one of the tools that has made aviation incredibly safe. You can harness this way of thinking to make your operating room safer as well. Explain the concept to your team. Doing so both respects their professionalism and will helps them get on the same page with you.

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