How Nurses Evaluate Causation in Medical Malpractice Claims
In medical malpractice litigation, establishing breach of standard care is only half the battle. The critical question—and often the most contentious one—is simple but profound: Did the defendant’s breach actually cause the plaintiff’s injury?
This is where clinical expertise becomes indispensable. Attorneys need nurses to answer this question with credibility and clarity.
Why Causation Matters
Without causation, there is no malpractice claim, regardless of how clear the breach was.
A patient may have received substandard care. The breach may be obvious. But if the injury would have occurred anyway, the claim fails.
Courts require causation to be established to a reasonable probability—more likely than not. Not just possible. Not even plausible. Probable.
That’s a clinical question, and nurses are uniquely positioned to answer it.
Step 1: Establish the Standard of Care
Before you can prove a breach caused injury, you must first prove the breach existed.
Nurses analyze what a reasonably competent nurse would have done in the same circumstances. This requires understanding:
The clinical setting (ICU vs. med-surg, rural vs. metropolitan hospital)
Patient acuity and complexity
Available resources and staffing
Facility policies and protocols
Professional standards (ANA guidelines, specialty certifications, regulatory requirements)
The time period (standards evolve; 2015 is different from 2022)
Why it matters: The stronger and clearer the breach, the more direct the causation argument becomes.
Step 2: Map the Causal Chain
Causation isn’t abstract. It’s a sequence:
Breach → Omission → Consequence → Injury
Let’s make this concrete.
Real example:
A post-operative patient requires vital sign monitoring every 15 minutes for the first two hours. The nurse, overwhelmed with other patients, checks vitals only once—at 30 minutes post-op.
At 45 minutes, the patient develops early signs of hemorrhage: rising heart rate, falling blood pressure. Without monitoring, these aren’t caught.
By the time vitals are rechecked two hours post-op, the patient’s blood pressure has dropped significantly. Organ perfusion is inadequate. The patient suffers acute kidney injury.
The causal chain:
Breach: Failed to monitor per protocol
Omission: Early warning signs went undetected
Consequence: Delayed recognition and intervention
Injury: Acute kidney injury from inadequate perfusion
The more direct and linear this chain, the stronger the causation argument.
Step 3: Distinguish Contributing Factors from Causative Factors
Here’s where clinical analysis gets nuanced.
Most injuries involve multiple factors. A patient may have:
Pre-existing diabetes
Chronic kidney disease
Sepsis from an unrelated source
Medication side effects
Self-care non-compliance
The question isn’t whether these factors exist. It’s whether the defendant’s breach was a substantial factor in producing the injury.
Critical analysis:
Did the patient’s risk factors increase vulnerability to harm from this breach?
Would the injury have occurred anyway, even with proper care?
Was this breach a necessary cause or merely one of several causes?
Nurse’s role: Credibly explain whether the breach was the pivotal factor or just background noise.
Step 4: Tell the Story the Records Show
Medical records are the evidence.
Nurses review them looking for:
Omissions: Missing vital signs, absent assessments, gaps in monitoring
Deviations: Where actual care diverged from protocol
Timing: When something should have happened vs. when it did
Progression: How did the patient’s condition change? When? Why wasn’t it caught?
What should have been documented but wasn’t? That gap tells the causation story.
A patient who deteriorated post-op but had no vital signs documented for hours. A patient with fever who received no assessment for sepsis. A medication administered but never verified in the chart.
These gaps aren’t just evidence of poor documentation. They’re evidence of the mechanism by which the breach caused injury.
Step 5: Apply Clinical Reasoning
Now bring it all together with clinical judgment.
A nurse expert can explain why the breach would reasonably cause injury using patient physiology, timing, and severity.
Example from sepsis:
“When a post-operative patient is not monitored, early signs of sepsis—fever, tachycardia, altered mental status—remain unrecognized. Each hour without antibiotics significantly increases mortality risk. If vital signs had been checked every 15 minutes as protocol required, these changes would have been caught at the 30-minute mark. The physician would have been notified immediately. Antibiotics would have been started. That’s a 3-4 hour difference in treatment timing, which is critical in sepsis. More likely than not, that delay was a substantial factor in the patient’s adverse outcome.”
That’s not speculation. That’s clinical reasoning grounded in pathophysiology and clinical experience.
Step 6: Evaluate Temporal Relationship
Timing matters.
The breach should occur before the injury, in a medically plausible timeframe. If there’s a long, unexplained gap between the breach and injury, other causes may have intervened.
Strong temporal relationship:
Nurse fails to monitor
Patient deteriorates
Hours pass without intervention
Patient is harmed
Weak temporal relationship:
Nurse fails to follow a prophylactic protocol
Patient is fine for weeks
Then, months later, unrelated event causes injury
Proximity in time strengthens causation.
Step 7: Answer “But For” Causation
The legal standard often hinges on this question:
“But for the defendant’s breach, would the injury have occurred?”
The answer must be framed in clinical probability, not just possibility.
Strong language:
“It is reasonably probable that…”
“More likely than not…”
“To a reasonable degree of nursing certainty…”
Weak language:
“It’s possible that…”
“It could have happened…”
“It might have occurred…”
Courts require probability, not possibility.
What Makes Causation Strong
✅ Clear, documented breach of standard care
✅ Direct connection between breach and injury
✅ Timing that makes clinical sense
✅ Medical records supporting the sequence of events
✅ Medically plausible mechanism of injury
✅ No intervening causes that break the chain
✅ Alternative explanations are unlikely
✅ Clinical literature and experience support the conclusion
What Makes Causation Weak
❌ Breach is minor or the deviation from standard is unclear
❌ Long, unexplained gap between breach and injury
❌ Multiple other factors clearly contributed
❌ Injury likely would have occurred anyway
❌ Medical literature shows the injury is expected outcome despite proper care
❌ Pre-existing condition or comorbidity likely caused injury
❌ Plaintiff’s own decisions or non-compliance intervened
❌ Clinical mechanism doesn’t make sense
The Nurse’s Professional Role
Nurses don’t determine legal causation. Judges and juries do.
But nurses translate complex clinical facts into understandable stories. We provide credible professional opinion. We help attorneys understand the clinical significance of omissions. We connect breaches to actual patient harm.
The strongest nursing analysis answers the attorney’s core question clearly:
“Based on your clinical experience, is it reasonably probable that the defendant’s breach caused this injury? If so, how?”
Why This Matters
A well-analyzed causation argument can be the difference between a strong case and a weak one—between settlement and dismissal, between justice for the plaintiff and immunity for the defendant.
Conversely, weak causation analysis can undermine even the most obvious breach.
This is why attorneys turn to nurses for medical record review and expert analysis. Your clinical expertise isn’t just helpful. It’s essential.
CALL TO ACTION
Need Help Analyzing Causation?
At Nurse Becca Consulting, we provide medical record review and causation analysis for personal injury attorneys, insurance defense counsel, and healthcare risk management professionals.
We translate clinical facts into credible expert opinions that help judges, juries, and mediators understand the causal connection between breach and injury.
Whether you’re building a plaintiff’s case or defending against a malpractice claim, we can help.
Learn More About Our Services | Request a Consultation
ABOUT NURSE BECCA CONSULTING
Rebecca Nixon is a registered nurse and legal nurse consultant with extensive experience in medical-record analysis, causation evaluation, and expert testimony. She helps attorneys understand complex clinical facts and build stronger cases.
Services include:
Medical record and medical-necessity review
Causation analysis
Standard of care evaluation
Expert witness consultation
Litigation support
Contact Nurse Becca Consulting: Attorneys may email nursebecca@nursebeccaconsulting.com
