I am writing this post so that circulating nurses in the cardiac surgical OR understand the rationale behind my idea for “yet another checklist”, a proposed timeout at 6 hrs after starting a case. I recognize that this is a change in our routine practice. Such changes can be met with resistance. I welcome your feedback, particularly your thoughts on how my ideas outlined below are off-track.
Let’s start with the obvious. Standard operating times for cardiac surgery are 3-5 hours. More technically complex cardiac surgery cases, something other than a CABG or low risk isolated valve surgery, might require longer times in but rarely exceed >6 hrs. Excessively long cases demand levels of physical and mental exertion from the surgeon and anesthesiologist that can lead to fatigue and frustration, eventually taxing the patience and temperment of the whole team. Once this happens, the team can lose situational awareness, meaning they are lost. A variety of things can be done well beforehand to reduce this risk. Complex cases should be planned out appropriately – scheduled electively well in advance and not after hours or the weekend and a team should be provided that has extensive experience working together. A multidisciplinary discussion among a preoperative Heart Team committee is often useful to optimize the preoperative work-up and fine-tune the intraoperative strategy. In some cases, a short period of preoperative hospitalization for medical optimization and respiratory and/or physical therapy reduces the risks of surgery (known as prehabilitation). All this proactive planning undoubtably helps.
However, the best laid plans often go awry, particularly during prolonged complex cases. Such cases illustrate the wisdom of Mike Tyson who once said: “everyone has a plan until they get punched in the mouth”. Nothing punches the team in the mouth and renders its preop plans more useless than cases violating all expectations by lasting >6 hrs. Yet many teams fail to recognize the hazards of this 6 hr threshold in real time; its signals are often ambiguous – the patient’s blood pressure, extent of bleeding and acidosis and even the degree of tension among the team are abnormal but not so off-track as to provoke obvious alarm. The surgeon, who is best equipped to recognize how problemmatic the case has become, often fail to communicate that fact to others on the team that could help. This happens because everyone, even an expert surgeon, demonstrate a paradoxical response to increasing levels of stress. Moderate stress improves performance. While optimal stress can lead to “flow”, a state that absorbs one’s full attention and makes one lose track of time, further increase in stress absorbs even more attention in a way that causes cognitive tunneling. This hyperfocus steals both technical abilities and clinical judgment by making the surgeon blind to issues readily apparent to others in the room. OR team members hesitate to speak up to the surgeon because it is difficult to discriminate whether he/she is engrossed in a state of flow or completely lost in the weeds.
All this can lead to wide array of hazards that are often overlooked by the increasingly distracted surgeon and other members of the surgical team:
- Leg ischemia – Cardiac surgery often uses a perfusion cannula placed into the femoral artery. Because this cannula can obstruct the femoral artery, it is placed here under the assumption that the case will not be prolonged beyond a time in which ischemia might become a problem (i.e >6 hrs). When the case unexpectedly prolonged, the chance of clinically significant ischemia in the leg downstream of that obstruction rises significantly. An unexplained lactic acidosis or red discoloration of the urine (myoglobinuria) are often the telltale signs of that happening.
- Leg reperfusion syndrome – If the perfusion cannula is removed from the femoral artery and the blood flow into the leg dramatically increases after a prolonged period, a dangerous reperfusion syndrome can occur and is associated with acidosis, myoglobenemia, and hypotension.
- Life threatening blood loss – Prolonged surgery is often associated with excess bleeding. This can deteriorate into the lethal triad of acidosis, hypothermia and coagulopathy. Safe surgery requires a proactive effort to anticipate these reversible problems, which includes the surgeon taking a step back from the task absorbing their attention and taking care of bleeding sites.
- Need for a copilot – A long, complex case is like flying a jumbo jet across the Atlantic in turbulent weather. Attempting that flight with just a single pilot and no copilot is an unnecessary risk. Asking for a second surgeon to serve as a copilot during a long case can help take team’s eyes off the problem and put them on the solution. The power of a fresh set of eyes was illustrated by the famous video entitled the “invisible gorilla”. Many observers of the video asked to watch a basketball being passed between players end up blind to the fact that a gorilla walks through the middle of the scene. It often takes a second surgeon to see the gorilla in the room.
- Infection control – The risk of infection correlates with the length of the procedure. Hyperglycemia becomes more common. Antibiotics may need to be redosed to maintain therapeutic levels. A reduction in skin temperature can lead to tissue desiccation and increase the probability of wound contamination. Breaks in sterile technique often add up and become more common as the case continues to drag on.
- Patient positioning – The positioning of legs and arms during surgery can be appropriate for short cases but need to be reassessed once the case is unexpectedly prolonged. Pressure injury on nerves and stretch injury to joints are common problems in these prolonged cases that need to be anticipated.
- Limited resources – Having to do a case after hours is tough under any circumstance. It is possible that necessary equipment, supplies and staff might become unavailable when the case time extends beyond the expected window of normal working hours. Introducing this inconsistency of resources into to the case at the 6 hr time point can lead to case interruptions and further prolong OR times
As these issues accumulate, the case veers off in unanticipated directions. Losing situational awareness, while rare and unpredictable, is always dysfunctional and dangerous. In aviation, it is known as a pilot that does not stay ahead of the airplane. Whether happening in the OR or cockpit, this risk serves as a brutal audit of the team’s capabilities. The high performing team responds by rising to the occasion. Team members cross-check and cross-cover each other more than under standard conditions. They respond to fatigue by deliberately modulating their level of alertness. Knowing that their exhaustion increases the risk of deviating from or missing important details, they are extra careful to pay attention and stay mindful. I have had the honor of working within these types of teams. The results they produce can be outstanding. They are wise enough to know that sometimes complex cases don’t go well despite doing everything right, an insight that improves their resilience.
There is a simple tool that helps the team avoid the dysfunction associated with a long OR time: a checklist. Once a case extends beyond 6 hrs, the circulating nurse looks for an appropriate break in the action and initiates a predefined checklist. Obviously, the checklist should systematically inquire about the seven commonly overlooked hazards associated with a long case that are listed above. However, the most important goal of this timeout is for the team to regain full situational awareness: where have we been, where are we now, what caused us to get here? Sometimes accurate insight in a complex case requires the patience to piece together insights from several different team members. The team struggling through these cases often feels like blind men trying to describe an elephant by touch. Only when everyone seeks out and understands each other’s perspective (their “part of the elephant”) can any conclusion adequately reflect the truth.
Crossing the 6 hr timeline signals a “threat”. Aviation terminology calls this an “unintended state”. The checklists and the discussion it entails empowers the team to detect—and act on—that threat and the errors it can trigger. Like Mr. Tyson, General Eisenhower famously recognized that “plans are useless but planning is indispensable.” A battlefield can feel like the OR in a tough and prolonged case. Sticking with our original plan creates an illusion of control. We naturally do this based on inherent cognitive shortcuts known as the confirmation bias and escalation of commitment. We must trust the checklist at 6 hrs to combat this tendency and rethink whether we are on the correct course. Our patients are depending on it.