Patient Safety in the Cath Lab: Someone Has to Keep Flying the Plane

On December 29, 1972, Eastern Air Lines Flight 401 took off from New York en route to Miami. As the flight approached Miami International Airport, on descent, a broken indicator light on the control panel suggested to the pilots that the landing gear was not in place. According to the cockpit voice recorder, the captain and his two copilots all attempted to work through the problem. They worked through various procedures, including taking the light apart, and sending the flight engineer below to inspect the landing gear. Unfortunately, as they were all distracted for several minutes, they failed to notice that they had accidentally disengaged the autopilot, and that they were gradually losing altitude. In addition, no one noticed a low-altitude warning alarm that also went off, and the plane flew into the ground at high speed. The resulting crash killed 101 of the people on board. Ironically, the landing gear was found to be locked in the proper position, and the disaster was due to an indicator light bulb that had burned out, along with a crew that was too distracted to fly the plane. Their problems all started from a light bulb that had merely burned out.

The above example is a case study from the aviation industry, which has a crash rate of less than 1:100,000 flights, and is considered the leading system in error analysis and safety corrections. In contrast, the healthcare industry has a much higher error rate of 4-8% (in terms of pharmacy errors), and leads to an estimated 44,000–98,000 deaths annually from adverse events, equivalent to 1 airplane crash each day. The foundation of the patient safety movement is that these adverse events are not unavoidable, and that we can learn from these and other errors to create as foolproof a system as possible.  

Team resource management

Eastern Airlines Flight 401 is used as a case study in poor “crew resource management”. Team resource management can be defined as a management system that makes optimum use of all available resources — equipment, procedures and people — to promote safety and enhance operational efficiency (Figure 1). Essentially, this concept can be summarized as distributing essential roles amongst the available team members according to their skills, and ensuring that “someone is always flying the plane”. Just as in soccer, basketball, or hockey, what happens if everyone heads straight for the ball or puck? No one is covering where the ball is (or could be) headed next, and the other team scores.  As Wayne Gretzsky has noted, “Skate to where the puck is going, not where it has been.” A team that has good situational awareness has all of their zones covered (Figure 2), and will win over any team that relies on a single star player. 

Teamwork in the cath lab 

In the cath lab, the operating physician might be devoting their full attention to opening that difficult chronic total occluded artery, and thus cannot possibly be aware of everything going on with the patient. Just as flying a plane means always watching the speed, altitude, fuel, and power, there are multiple parameters of the patient and procedure that must be continuously monitored by team members. The patient’s pulse, blood pressure, electrocardiogram (ECG), and oximetry are the most obvious, but also the easiest to overlook when exciting things are happening inside the cath lab, like a coronary dissection. Less frequently considered is the presence of dampening or ventricularization of the arterial pressure waveform, which should be immediately reported to the operator before they inject contrast against the wall of a coronary artery, causing dissection or ventricular fibrillation. Finally, the amount of contrast used, radiation exposure, and procedure time should be at least intermittently monitored and reported to the physician, so that they can make a decision to continue, abort, or stage a complex procedure.

The standard cath lab roles include a recorder, who should be continuously monitoring the vital signs and pressure tracing. The recorder should avoid the temptation to ‘help’ with an issue in the lab and abandon their station. The other role includes moderate sedation nurse, who, in most facilities, is required to have no other duties except for monitoring the patient’s level of sedation and respiration, as oversedation may be overlooked. Although in many cases the level of sedation for coronary procedures is low enough to not risk loss of the airway, having the recorder or sedation nurse also serve as a circulator during a complex percutaneous coronary intervention (PCI) risks missing critical changes in the patient’s status.

Some of the most frightening moments in the lab occur when there is a sudden change in patient status. The patient might go into ventricular fibrillation or bradycardia after an angioplasty. The patient might lose capture after a pacemaker lead falls out, or lose their escape rhythm from complete heart block when the lead tickles their ventricle. The ST-segments might elevate after PCI because of distal embolization of thrombus or air. An effective cath lab team identifies and reports all of these changes, and begins the appropriate response (defibrillation, pacing, or intra-aortic balloon pump [IABP]) even before the operator requests it.

In a case shared with me recently, a patient’s change in status was not noticed by the cath lab staff at a major Boston teaching hospital. A new technologist, unfamiliar with the typical workings of the lab, decided to continually adjust the scale of the invasive blood pressure tracing to make the waveform fill the screen. As the scale changed from 200 mmHg to 100 mmHg and finally to 50 mmHg (example in Figure 3), the waveform probably looked the same to the operator from across the table, at least until the patient coded.  

Take stock of yourself and your team members

Situational awareness also means taking stock of your own capacities and those of your team members. New staff members have to be trained adequately and proctored. If you have been on call all night and are exhausted, you might not be the best person to scrub in on what is likely to be a long ablation case. Consider asking your supervisor for relief. Don’t try to be a hero. We have work-hour restrictions for residents and truck drivers, but not for cath lab staff or interventionalists, so self-awareness and regulation is necessary, along with good management. Similarly, an effective team requires everyone to be focused on the task at hand and in the moment. If a team member is distracted by outside issues or personality conflicts, they may be less effective in a crisis. Where possible, issues and disagreements should be resolved in an open manner before a case begins, so that team members can work together in a cohesive manner.  

I have been fortunate to work in many cath labs with effective and experienced teams that have saved me and my patients more times than I would like to admit. With good situational awareness and team resource management, your team will be ready for whatever comes your way.

If you have a cath lab safety question or case example to share, please contact me at arnold.seto@va.gov.

Reference

1. Institute of Medicine Report, To err is human: building a safer health system.  Kohn L, Corrigan J, Donaldson M, eds. National Academy of Sciences. 2000.  Available at: https://www.nap.edu/books/0309068371/html.

Dr. Arnold Seto can be contacted at arnold.seto@va.gov.