Air Embolism
Cause Mapping Example:
We will look at the potential for air embolism as an example of how the Cause Mapping process can be applied to a specific incident that COULD happen. This is known as a proactive Cause Map. We will follow a three-step root cause analysis investigation process. 1) Define the problem, 2) Conduct the analysis and 3) Identify the best solutions. Each step will be discussed below.
Step 1. Define the Problem
Normally, the first step of the Cause Mapping approach is to define the problem by asking the four questions: What is the problem? When did it happen? Where did it happen? And how did it impact the goals? However, since we are looking at an incident that COULD happen, we won't bother with the "when". After all, the purpose of doing this investigation is to prevent an air embolism from occurring. We write down "the problem” on the first line. Here, it's an air embolism.
The physical location of concern is the vascular system. The equipment being used might be a catheter, and the task being done may be surgery. (Both of these situations can contribute to air embolisms.) .
Next, we look at the impact to the overall goals. The number one goal of a medical facility is patient safety. An air embolism is an impact to the patient safety goal because of the potential for tissue damage, death, or serious injury. Additionally, the compliance goal is imapcted because patient death or serious disability resulting from an air embolism is a "never" event. It's also a hospital-acquired condition that results in no reimbursement from Medicare, so the non-reimbursable hospital costs (estimated to be more than $70,000) are an impact to the materials and labor goal. There may be other goals affected but the patient safety goal will be the focus of our investigation.
Step 2. Identify the Causes (The Analysis)
Next the incident is broken down into causes which are captured on the Cause Map. The Cause Map starts by writing down the goals that were affected as defined in the problem outline.
The analysis can continue by asking Why questions and moving to the right of any of the cause-and-effect relationships above. In this example all the impacts to the goals are caused by an air embolism. Now our Cause Map looks like this:
We continue to ask Why questions and add causes to our map. An air embolism can occur if a pressure gradient favors the ingress of air into a blood vessel AND the vasculature is exposed to air. We should these two causes joined by an "AND" because both causes must be present to produce the effect..
We continue to ask Why questions for each branch of the Cause Map in turn. First, what causes the pressure gradient? It could be caused by an air entry site more than 5 centimeters above the right atrium, which could be caused by surgery performed in an upright position. It could also be caused by low central venous pressure. (It could also be caused by both, so we use "AND/OR" to connect the causes. Low central venous pressure could be caused by decreased blood volume (hypovolemia), such as that from dehydration, or deep inspiration (coughing or laughing), or both.
The vasculature could be exposed to air because a blood vessel is open, possibly because a catheter is being removed or surgery is being performed. Or the air could enter through a venous catheter (more on this below).
Air could enter the venous catheter if the catheter was damaged, potentially due to a crack in the central venous access device, or a disconnection between catheter connections. Additionally, air could enter the catheter if the catheter was opened, or air was forced into the catheter.
Even more detail can be added to this Cause Map as the analysis continues. As with any investigation the level of detail in the analysis is based on the impact of the incident on the organization’s overall goals.
Step 3. Select the Best Solutions (Reduce the Risk)
We use the Cause Map we've created above to identify all the possible solutions for preventing air embolisms so that the best solutions can be selected. The more detail we add to our Cause Map, the easier it will be to brainstorm possible solutions. The solutions we find are shown above the Causes they control, as shown below.
Shown below is the full Cause Map, with 26 causes and corresponding solutions.
Solutions are evaluated based on the acceptable risk level determined by an organization's overall goals. Once solutions are selected for implementation, they are assigned a person responsible and a due date and added to the action items list. The action items listed based on this analysis is shown below.
Click on "Download PDF" above to download a PDF showing the Root Cause Analysis Investigation.
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