See the attached for a brief description of the concept of Damage Control Surgery.
See the attached pdf for the basics of trauma demographics.
“What we know is not much. What we don’t know is immense.”
His last words.
So true of science, medicine, and anesthesiology.
Although hypothermia reduces intracranial hypertension, a randomized trial in the New England Journal of Medicine found that hypothermia did not improve functional recovery as compared with standard care alone:
The trial was stopped early because the results suggested that outcomes were actually worse with hypothermia.
The accompanying editorial points out the obvious. Treating traumatic brain injury is complicated…
“Unlike the successes for almost every other organ, resuscitation of the brain has been a fitful pursuit, punctuated by enthusiasm in early trials and subsequent disappointment.
The ostensible purpose of using hypothermia was its fairly dependable effect in reducing intracranial pressure, and it has been thought to have an additional neuroprotective effect. Interpretation of these disappointing results is, as usual, complicated.
Would the benefit have been more favorable for hypothermia in the Eurotherm3235 Trial if only patients who did not have an adequate response to what the authors term “stage 2” treatments (e.g., hyperosmolar therapy) had been enrolled?
The effects on mortality and functional outcome of all the treatments we currently use — hypothermia, craniectomy, drainage of cerebrospinal fluid, hyperventilation, and even hyperosmolar therapy — are probably smaller than we think, because severe head injury is an overwhelming and complex process involving neurons, glia, and vasculature. It may be that raised intracranial pressure compresses cerebral veins and creates a self-regenerating cycle of even higher pressure so that medical management becomes futile. This is not an excuse to allow elevated intracranial pressure to go unchecked, but it is an admonition to be discerning in the use of medical and surgical treatment, especially hypothermia. Given the diversity of protocols and treatments for severe head injury in different centers (e.g., the limited use of hypothermia in the United States as compared with Europe), the study by Andrews and colleagues is useful when interpreted with its limitations. Completely new approaches are needed for the control of intracranial pressure in order to design trials and treatments for severe traumatic brain injury.”
Because I’ve recently read this interesting book:
I’ve added a new category to this blog, “Medical Reversals.”
According to these Prasad and Cifu, a problem with this study on hypothermia is using a “surrogate” endpoint (ICP) to treat TBI patients, when what we are really concerned about is the effect of hypothermia on mortality and functional outcome.
This is how medical reversal happen. A small non-randomized, uncontrolled report is published. The treatment appears logical. We jump on the bandwagon. The treatment is adopted as “Evidenced Based.” Then a randomized trial is conducted and a medical reversal occurs. It may turn out that the treatment not only has no effect, but worse, it is HARMFUL. Unfortunately, it takes years before a reversal truly eliminates the flawed treatment.
In the category of “unrelated to trauma, per se,” a recently published New England Journal of Medicine article (Cardiac Complications in Patients Undergoing Major Noncardiac Surgery) is of importance to anesthesiologists.
For patients at high risk, the thirty day mortality from major non-cardiac surgery is 1-2% compared to 0.001% from intra-operative mortality. It doesn’t take much of a leap to understand why intra-operative deaths are so rare compared to thirty day mortality. Intra-operatively, the patient is cared for “beat-to-beat.” Unlike the delays that happen on the post-surgical ward, any intra-operative derangement is treated promptly by knowledgeable providers.
This article is important because it shines a light on the magnitude of thirty day mortality. This is a big problem. How is it that we have not perceived this “elephant in the room?” It happens because, we, in the acute care setting, do not view first hand that these patients die within thirty day of their operation. Unlike a death that happens in the OR, these 30-day deaths are invisible to the acute care provider. Operating room deaths get an immediate “root-cause analysis.” Deaths outside of the OR, after a prolonged hospital course or after discharge from the hospital do not receive the same scrutiny.
If we are to improve the thirty day mortality for these high risk patients, it makes no sense to decrease their level of care after they leave the PACU. Certainly, those patients that are truly critically ill will be sent to a step-down or ICU setting, where they will receive a higher level of care. However, this thirty day mortality is happening because we currently don’t appreciate how high risk these patients are. We incorrectly believed them to be at low risk, when they apparently are not. Alternatively, because these patients do well in the operating room owing to the high level of care there, we believe it is safe to discharge them to the floor.
This NEJM article suggests that many high risk patients apparently go unrecognized and do not receive the care required if we are going to decrease this 1-2% thirty day mortality after major non-cardiac surgery.
Who are these at-risk patients? They are patients we care for daily! They have the following characteristics:
- Age > 75
- Male sex
- Chronic conditions:
- Renal insufficiency
- Coronary artery disease
- Peripheral vascular disease
- Cerebrovascular disease
- Congestive heart failure
- Atrial fibrillation
- Severe aortic stenosis
- Acute conditions:
- Recent high-risk coronary
- Recent placement of coronary-
- Recent stroke
- Acute trauma (e.g., hip fracture)
- Urgent or emergency surgery
- Recent high-risk coronary
I see more patients like this at night than I see so-called normal patients. Yet these patient are routinely discharge to the floor from the PACU.
The article discusses in detail:
- Clinical Risk Indexes
- Noninvasive Cardiac Testing
- Measurement of Cardiac Biomarker Levels (an eye opener for me)
- In a meta-analysis of individual data from 2179 patients, of whom 235 died or had a myocardial infarction (the primary outcome) within 30 days after noncardiac surgery, an elevated preoperative plasma level of natriuretic peptide (i.e., a B-type natriuretic peptide [BNP] level of ≥92 ng per liter or an N-terminal pro-BNP [NT-proBNP] level of ≥300 ng per liter) was the strongest independent preoperative predictor of the primary outcome (odds ratio, 3.40; 95% CI, 2.57 to 4.47).
- The cost of measuring natriuretic peptide levels is much lower than the cost of a stress test. Furthermore, results can be obtained within minutes with testing at the point of care. Measurement of natriuretic peptide levels is thus preferable to stress testing because it is more accurate and convenient, faster, and less expensive. In fact, measurement of natriuretic peptide levels costs less than an internal medicine or cardiology consultation, so the test might be used to decide which patients should be referred for consultation with a specialist.
The article also discusses Perioperative Interventions:
- Preoperative Coronary Revascularization
- Interventions Targeting the Stress Response
- It’s “complicated” (my assessment)
- α2-adrenergic agonists
- Transfusion threshold
- A restrictive transfusion strategy after any noncardiacsurgery is probably prudent unless proved otherwise
- Shared care
- A meta-analysis showed lower mortality among patients who underwent surgery for a hip fracture and whose care was co-managed by surgeons and geriatricians, as compared with surgeons alone.
Finally, the article discusses Postoperative Monitoring:
- Monitoring for Hypoxemia, Hemodynamic Compromise, and Myocardial Ischemia
- This is what anesthesiologists do “beat-to-beat” in the OR.
- Data suggest that new monitoring strategies are needed on surgical wards if postoperative care is to achieve improvements similar to those that have occurred in intraoperative care.
- Measurement of Troponin Levels
- Without monitoring of perioperative troponin levels during the first few days after surgery in patients with known vascular disease or risk factors, the majority of myocardial infarctions and injuries will go undetected.
- There may also be value in obtaining a measurement of troponin levels before surgery, because it may provide independent prognostic information.
We can and we must better serve this patient population.
The American Society of Anesthesiologists (ASA) has recommended a curriculum for anesthesia residents.
This blog will attempt to provide the “medical knowledge” that the ASA recommends for resident education.
Get to these pages by hovering over “A Trauma Curriculum for Anesthesiology Residents” in the “menu bar” and choosing from the dropdown topics…