More on a 68-Year-Old Woman Whose Hip Fracture Requires Urgent Surgery

Author:
Ronald N. Rubin, MD—Series Editor

Citation:
Rubin RN. More on a 68-year-old woman whose hip fracture requires urgent surgery. Consultant. 2017;57(5):286,288.

The “What’s the ‘Take Home’?” article in the March issue of Consultant¹ described the case of a 68-year-old woman who had sustained a hip fracture requiring urgent surgery. The article discussed the issue of stratifying the risk for the occurrence of cardiovascular complications including death in the preoperative evaluation of patients undergoing major noncardiac surgery. Using the same patient’s case, this article addresses the subsequent issue of the role of preoperative, intraoperative, and postoperative maneuvers that might be useful in preventing adverse cardiovascular events among these patients.

The woman had fallen after tripping on a curb. The ambulance personnel confirmed her right leg to be shortened and laterally rotated, and they transported her to the hospital where an acute intertrochanteric fracture was confirmed.

More complete evaluation revealed that the woman had experienced no dizziness or syncope with the fall. She had osteoporosis, diagnosed by way of bone density evaluation, and had been taking calcium and vitamin D supplementation. She reported that her health was otherwise good, with no acute events or hospitalizations in recent years. There was no history of overt congestive heart failure (CHF) or coronary artery disease (CAD), and she was able to ascend at least one flight of stairs without dyspnea or chest pain.

She had had type 2 diabetes mellitus for a decade, which had been managed with an insulin regimen, and she had a recent hemoglobin A_1C level of 6%. Kidney disease had developed in the past 3 years, attributed to her diabetes, with a recent creatinine level of 2.4 mg/dL.

Preoperative laboratory test results included a normal complete blood cell count (CBC). The results of a comprehensive metabolic panel included a blood glucose level of 130 mg/dL, a blood urea nitrogen level of 34 mg/dL, a creatinine level of 2.6 mg/dL, and otherwise normal values.

Electrocardiography revealed nonspecific ST-T segment changes but was otherwise normal. Baseline natriuretic peptide levels were normal, and an echocardiogram showed an ejection fraction of 50%.

The patient underwent placement of a rod to stabilize and repair the pelvic fracture. The procedure went uneventfully, and after stabilization in the recovery room, the plan was for her to be transferred to floor care. In the recovery room, her pulse was 104 beats/min, her blood pressure was 155/88 mm Hg, her respiratory rate was 14 breaths/min, and her oxygen saturation was consistently above 94%. A repeated CBC showed that her hemoglobin had dropped from 13.8 to 10.8 g/dL postoperatively. The wound drain was not showing excessive bleeding.

Answer on next page

Answer: D, perioperative measurement of troponin levels

As discussed in last month’s article, even in 2017, there is a finite, and in some situations, significant risk for operative and/or perioperative (ie, within 30 days of induction of anesthesia) complications or mortality.² The most dangerous risks are for cardiac complications—CHF, acute myocardial infarction (AMI), and cardiac arrest. And, in patients who sustain such complications, the mortality rate is at least 33%.² Therefore, any diagnostic and/or therapeutic strategies to enable the preemptive diagnosis and treatment of such complications are important in making major noncardiac surgery safer for the large population of patients requiring it, the number of whom will only grow larger as the US population ages.

After having previously discussed preoperative risk assessment for possibly fatal cardiovascular complications in patients undergoing major noncardiac procedures, let us turn attention to the role of perioperative maneuvers that might help prevent these untoward events.

The first intervention to review is targeting the significant stress syndrome associated with any trauma (eg, hip fracture) leading to the need for surgery and the sympathetic responses to both the induction of anesthesia and the procedure itself. Good clinical trials have been performed in large numbers of patients on the perioperative prophylactic use of β-blockers (eg, metoprolol) and/or α₂-adrenergic agonists (eg, clonidine).^2-5 The results have been mixed. For example, β-blockade indeed reduced the risk of nonfatal AMI, yet it increased the risk of hypotension, stroke, and mortality.⁴ Clonidine use had a lower risk of hypotension, but it had no effect on the risk of AMI or death.⁵ Refinements and individualization schemes for these agents continue to be developed, but for now, the general use of these maneuvers (Answer B) is not the most valuable choice.

The empiric perioperative use of aspirin has the logic of allegedly reducing the risk of AMI from subclinical CAD via its antithrombotic effect. Data from the POISE-2 trial were quite clear, however.⁶ There was no protective effect from aspirin in regard to perioperative AMI, stroke, or death, but there was a trend toward increased major bleeding in the aspirin-treated group. Thus Answer C is not correct in our patient’s case.

When and how much to sustain oxygen carrying via blood transfusions has been studied in a variety of settings in recent decades. In most instances and settings, a conservative strategy using 8.0 g/dL as a transfusion trigger has been shown to be noninferior to more “liberal” or aggressive transfusion triggers of 10 g/dL. In fact, a trial of transfusion in high-risk patients after hip-fracture surgery confirmed this finding,⁷ such that Answer A is not correct for the patient presented here.

What has been demonstrated to be an effective risk-reduction maneuver in the perioperative setting is monitoring for asymptomatic myocardial ischemia and infarction using cardiac troponin levels. Elevated troponin levels clearly indicate an increased risk of death within 30 days, regardless of whether the cause of death is nonischemic (eg, sepsis, pulmonary embolism), ischemia without classic AMI, or definitive AMI itself, with quite high mortality rates ranging from 7.8% to 26.3%.^2,8 When patients in this group are identified via an elevated troponin level, theoretically effective treatments (such as β-blockade, surgical revascularization, and higher transfusion thresholds) that are not effective in an across-the-board population will very likely be efficacious in this subgroup as secondary prevention. Therefore, Answer D is the optimal choice here.

Patient Follow-Up

In the perioperative period, the patient had no complications such as symptoms or signs of angina or CHF. Her postoperative hemoglobin level stabilized in the 9 to 10 g/dL range without the need for blood transfusions. Her blood pressure and pulse stabilized within normal ranges. Results of daily troponin level measurements were normal, and she was discharged for rehabilitation on day 5. At 6 weeks postoperatively, she was ambulatory, without complications or other sequelae.

Ronald N. Rubin, MD, is a professor of medicine at the Lewis Katz School of Medicine at Temple University and is chief of clinical hematology in the Department of Medicine at Temple University Hospital in Philadelphia, Pennsylvania.

REFERENCES:

1. Rubin RN. A 68-year-old woman who has sustained a hip fracture and requires urgent surgery. Consultant. 2017;57(3):178-179.
2. Devereaux PJ, Sessler DI. Cardiac complications in patients undergoing major noncardiac surgery. N Engl J Med. 2015;373(23):2258-2269.
3. McFalls EO, Ward HB, Moritz TE, et al. Coronary-artery revascularization before elective major vascular surgery. N Engl J Med. 2004;351(27):2795-2804.
4. POISE Study Group. Effects of extended-release metoprolol succinate in patients undergoing non-cardiac surgery (POISE trial): a randomised controlled trial. Lancet. 2008;371(9627):1839-1847.
5. Devereaux PJ, Sessler DL, Leslie K, et al; POISE-2 Investigators. Clonidine in patients undergoing noncardiac surgery. N Engl J Med. 2014;370(16):1504-1513.
6. Devereaux PJ, Mrkobrada M, Sessler DI, et al; POISE-2 Investigators. Aspirin in patients undergoing noncardiac surgery. N Engl J Med. 2014;370(16):​1494-1503.
7. Carson JL, Terrin ML, Noveck H, et al; FOCUS Investigators. Liberal or restrictive transfusion in high-risk patients after hip surgery. N Engl J Med. 2011;365(26):2453-2462.
8. Devereaux PJ, Xavier D, Pogue J, et al; POISE (Perioperative ISchemic Evaluation) Investigators. Characteristics and short-term prognosis of perioperative myocardial infarction in patients undergoing noncardiac surgery: a cohort study. Ann Intern Med. 2011;154(8):523-528.