Ah, blood. That sweet nectar of life that quiets angina, abolishes dyspnea, prevents orthostatic syncope, and quells sinus tachycardia. As a cardiologist, I am an unabashed hemophile.
But we liberal transfusionists are challenged on every request for consideration of transfusion. Whereas the polite may resort to whispered skepticism, vehement critics respond with scorn as if we’d asked them to burn aromatic herbs or fetch a bucket of leeches. And to what do we owe this pathological angst? The broad and persistent misinterpretation of the pesky TRICC trial (N Engl J Med. 1999;340:409-417). You know; the one that should have been published with a boxed warning stating: “Misinterpretation of this trial could result in significant harm.”
Point 1: Our Actively Bleeding Patient is Not a TRICC Patient.
They were randomly assigned to either a conservative trigger for transfusion of < 7 g/dL or a liberal threshold of < 10 g/dL. Mortality at 30 days was lower with the conservative approach — 18.7% vs 23.3% — but the difference was not statistically significant (P = .11). The findings were similar for the secondary endpoints of inpatient mortality (22.2% vs 28.1%; P = .05) and ICU mortality (13.9% vs 16.2%; P = .29).
One must admit that these P values are not impressive, and the authors’ conclusion should have warranted caution: “A restrictive strategy ... is at least as effective as and possibly superior to a liberal transfusion strategy in critically ill patients, with the possible exception of patients with acute myocardial infarction and unstable angina.”
Point 2: Our Critically Ill Cardiac Patient is Unlikely to be a “TRICC” Patient.
Another criticism of TRICC is that only 13% of those assessed and 26% of those eligible were enrolled, mostly owing to physician refusal. Only 26% of enrolled patients had cardiac disease. This makes the TRICC population highly selected and not representative of typical ICU patients.
To prove my point that the edict against higher transfusion thresholds can be dangerous, I’ll describe my most recent interface with TRICC trial misinterpretation
A Case in Point
The patient, Mrs. Kemp,* is 79 years old and has been on aspirin for years following coronary stent placement. One evening, she began spurting bright red blood from her rectum, interrupted only briefly by large clots the consistency of jellied cranberries. When she arrived at the hospital, she was hemodynamically stable, with a hemoglobin level of 10 g/dL, down from her usual 12 g/dL. That level bolstered the confidence of her provider, who insisted that she be managed conservatively.
Mrs. Kemp was transferred to the ward, where she continued to bleed briskly. Over the next 2 hours, her hemoglobin level dropped to 9 g/dL, then 8 g/dL. Her daughter, a healthcare worker, requested a transfusion. The answer was, wait for it — the well-scripted, somewhat patronizing oft-quoted line, “The medical literature states that we need to wait for a hemoglobin level of 7 g/dL before we transfuse.”
Later that evening, Mrs. Kemp’s systolic blood pressure dropped to the upper 80s, despite her usual hypertension. The provider was again comforted by the fact that she was not tachycardic (she had a pacemaker and was on bisoprolol). The next morning, Mrs. Kemp felt the need to defecate and was placed on the bedside commode and left to her privacy. Predictably, she became dizzy and experienced frank syncope. Thankfully, she avoided a hip fracture or worse. A stat hemoglobin returned at 6 g/dL.
Her daughter said she literally heard the hallelujah chorus because her mother’s hemoglobin was finally below that much revered and often misleading threshold of 7 g/dL. Finally, there was an order for platelets and packed red cells. Five units later, Mr. Kemp achieved a hemoglobin of 8 g/dL and survived. Two more units and she was soaring at 9 g/dL!