Precise Communication Saves Lives

On a foggy day on Tenerife island in 1979, jumbo jets from KLM and Pan Am airlines were inadvertently on the same runway waiting to takeoff and return back to their home countries of Amsterdam and USA.  The captain of a KLM jet radioed to Air Traffic Control (ATC) “we are now at takeoff”.  ATC assumed that ambiguous phrase meant they were at the takeoff position, not that they were actively taking off.  ATC responded “OK”.  That had a confirmatory effect that was not intended and led KLM to assume it was a clearance for takeoff. After initiating full thrust of the jet, the Pan Am captain called out on the radio at that time that he was blocking the way.  It was evident from black box recordings that the KLM captain did not hear this warning due to radio interference caused by both pilots talking at the same time and the message was not repeated. Both jets collided on the runway, immediately killing close to 600 people.

In healthcare, investigations of accidents that harm patients are done internally and in a confidential manner by hospital staff and employed physicians. As a result, they are not that effective at improving care. In contrast, aviation accidents are never confidential.  External federal regulators (NTSB, FAA) respond to the public’s demand to stop another tragedy by performing extensive and rigorous investigations of all accidents that lead to real change.  The international aviation community concluded that Tenerife happened due to poor communication between pilots and ATC.  The following corrective actions were implemented that remain in place today: English is required to be the common working language in a cockpit for all airlines worldwide, a list of standardized phrases was developed with the word “OK” prohibited.  The word “takeoff” is now spoken only when permission is given for actual takeoff.  Until actual permission is granted for takeoff, pilots and ATC controllers should use the word “departure”.  All ATC clearance to aircraft already lined up on the runway for takeoff must include the prefix “hold position”. 

It was also noted that a radio broadcast of a football match was heard in the background in tower transmissions in Tenerife.  That was criticized as a possible distraction from the difficult duties of ATC on that day.  Aviation regulations now prohibit any activity in the cockpit that is not required for safe operation during the critical moments of an airline flight and the use of cell phones or the internet at any point during a flight (see: cfr § 121.542).  Cell phones must be turned off inside ATC operational areas.

The unmistakable lesson of this tragedy is the mandate for concise, standardized aeronautical language in radio communications on a runway.  It is a slipup for a pilot to want to takeoff when there is another jet on the runway. Human slipups have happened since the beginning of our existence.  Communication techniques developed after Tenerife help trap inevitable errors so they don’t turn into a catastrophe.  Others on the team cross check safety critical decisions and actions of the pilot by being good listeners and asking clarifying questions.  Callouts/readbacks (also known as closed loop communication) are used to relay safety critical information. Tools such as checklists limit dependence on a fallible memory.  There is clear evidence that this culture change is working.  There has not been a fatal crash involving a US airline since 2009.

Performing anesthesia for a patient undergoing robotic cardiac surgery is at times analogous to navigating a jumbo jet around a crowded, foggy runway.  It is well recognized that the induction of anesthesia can upset the equilibrium of patients with cardiac problems.  A drop in blood pressure can make a sick heart unhappy. That leads to a further drop in blood pressure, potentially triggering a vicious cycle.  Everyone in a cardiac OR has seen this situation play out, which means that we have strong situational awareness and have developed many tactics to trap this issue before catastrophe.  Robotic surgery injects unfamiliar fog into that story.  A double lumen tube is placed in the airway and one of the lungs to be deflated in order to make space within the chest for robotic instruments to navigate. Will the same tactics we use to restore homeostasis with a standard open case work again now? All bets are off.  The best hope for safety is to maintain situational awareness and let the collective wisdom of a vigilant team uncover the right corrective responses.

We maintain situational awareness and create collective wisdom in an OR after clamping one lumen of a double lumen ETT by acting like a pilot poised to takeoff from a runway.  The entire team becomes vigilant for three major hazards. First is what happens when deflating the correct lung. It leads to an array of subclinical effects on cardiac pathophysiology that is usually (but not always) well tolerated by the patient. Mild arterial and alveolar hypoxia and hypercarbia trigger pulmonary vasoconstriction.  At times, that leads to right ventricular dysfunction and new onset tricuspid regurgitation.  Those issues can reduce cardiac output and coronary perfusion, leading to further reductions in pressure and cardiac output and potential for a vicious cycle that might not resolve with reinflating the lung.  The team must be ready to go on the heart-lung machine urgently as the only option.

Second is when the wrong lung was deflated.  After the clamp is placed on the ETT, narrow robotic ports are inserted into the chest through the ribs.  Similar to laparoscopic surgery, CO2 is then insufflated into the thorax at around 6-8 mmHg pressure in order to create space to operate by pushing the heart and lung away from the relevant anatomy. If the wrong lung in the opposite chest cavity was deflated, then that means both lungs will be compressed at this point.  This obviously will not be tolerated.  Even worse, the severe decompensation will not be anticipated leading to a less efficient response.

Third is when the double lumen tube is in an incorrect position so that clamping either lumen of the ETT results in complete cessation of air flow. This problem is usually immediately recognized by monitoring parameters on the ventilator and therefore quickly corrected.

We avoid error with one lung ventilation using the same concise standardized language as in the cockpit of an airline.  At the clinically appropriate time, the surgeon initiates a callout for isolation of either the left or right lung.  The CRNA or anesthesiologist reads back that request and places a clamp on the appropriate lumen of the ETT and callout where the clamp was placed – left or right sided lumen.  The surgeon will read back that callout and confirm this was the correct side.  It is not effective to say “clamped” or wait to callout that the clamp was placed until confirming an appropriate change in vent parameters.  The drapes covering up the ETT are analogous to having to communicate through a radio.  The surgeon cannot visually confirm which side of the ETT was clamped.  It is the precise moment that the clamp is placed that the surgical team is monitoring for any changes in hemodynamics that would prompt quick action.  The quicker the better.

The point of precise communication is not perfection in how we talk to each other. Perfectionism leads to paralysis. I accept that anyone can and will do it wrong. Just last week I whispered during a robotic coronary bypass case that I had “placed an occlusion device on the coronary”, which was quite different than my routine bark of “LAD occluded!” It is necessary to occlude a coronary artery while the heart is beating in order to sew a bypass graft. Doing this through a small thoracic incision – like the surgical drapes – hinders others seeing what I am doing and being vigilant for potential adverse effects. The surgical tech asked me if calling out things differently meant something. In other words, nonstandard language sent an unintended message. Heart surgery is too hard to put anyone at an unnecessary disadvantage. Working in a noisy operating room creates a signal to noise problem. Nonstandard language makes the search for signals among the noise more difficult, contributing to cognitive fatigue and taxing our bandwidth for staying vigilant. Being precise allows others to notice imperfection and focus on important things.

Another lesson from Tenerife is to watch out for two people speaking at the same time. This is a recipe for miscommunication. Throw in radio interference, surgical drapes or small incisions and this ever-present risk can turn lethal. When faced with predictable hazards, high performance teams establish ground rules. Ours is: “If you didn’t hear it repeated back, then you didn’t say it.” This puts full responsibility for communicating safety critical information on the sender (not the receiver) to keep trying until the intended recipient(s) acknowledges hearing it out loud. This rule helps defuse the defensiveness that often follows miscommunication. A common reaction is for the sender to take an impromptu poll of those in the room whether they heard what was said. This frustrating and futile debate is resolved by asking if ‘it was repeated back’. If not, ‘then you didn’t say it.’ Closed loop communication happens when everyone in the room acknowledges critical information verbally out loud and asks clarifying questions if necessary. Closing the loop also benefits the receiver. Remembering new information is enormously affected by what a receiver does immediately after hearing it. A common problem in an OR is being distracted by something which erases what you just heard. Repeating back what you heard improves memory through a psychological phenomenon called the “production effect.” There is a big memory advantage of saying words aloud over simply listening to them silently. Better memory helps to maintain situational awareness, so that everyone in the room is constantly aware of critical events in a procedure and able to project what might happen into the future.

It took a decade before the safety culture mandated by the Tenerife investigation led to improvements in airline safety.  Even if there is some resistance to this change right now, the truth is that this is the right thing to do. At some point the behaviors I am describing will certainly be mandated by regulation; the aviation industry has made it clear that the stakes are too high to accept ineffective communication. But why wait? Our patients want us to enhance their safety today.