In this report, we describe our experience with anesthesia management during ORIF of femoral neck fracture in a patient with severe HOCM. Intraoperatively, the patient was monitored using TTE.
Cases of HCM can be classified as hypertrophic nonobstructive cardiomyopathy, HOCM, apical HCM, mid-ventricular HOCM, and dilated-phase HCM [4, 6]. Additionally, patients who satisfy any of the following criteria are diagnosed as having a severe disease: moderate-to-severe restriction of physical activity (NYHA Class III–IV), a history of sustained ventricular tachycardia or ventricular fibrillation, and a history of hospitalization for heart failure or arrhythmia treatment. The patient in this case had been diagnosed as having HOCM previously on the basis of LVOT stenosis, MR, and SAM. Additionally, he had developed ventricular fibrillation, for which an ICD was subsequently implanted, and his physical activity was moderately or severely restricted. Therefore, he was diagnosed as having severe HOCM [4].
Although general or spinal anesthesia is usually selected for ORIF of hip fracture, both methods can cause hypotension in approximately one-third of patients [7]. By contrast, FNB, which has less of an effect on the sympathetic nerves, is expected to impact blood pressure to a lesser extent than spinal anesthesia [8,9,10]. Notably, decreased systemic vascular resistance due to anesthesia is associated with a high risk of an increased pressure gradient across the LVOT, which may create a stronger Venturi effect [4, 5, 11]. This could cause aspiration of the anterior mitral leaflet into the LVOT, thus worsening MR [4, 5, 11]. Our patient had HOCM with a pressure gradient > 50 mmHg across the LVOT. Therefore, we selected FNB and LFCNB for regional anesthesia to reduce the effect on systemic vascular resistance. However, insufficient anesthesia may enhance sympathetic nervous system activity, which would elevate the risk of increased cardiac contractility. This, in turn, could increase the pressure gradient across the LVOT and cause hemodynamic decompression [4, 5, 11]. To account for this risk, we did not initiate surgery in our patient until we had confirmed the achievement of sufficient anesthesia from the FNB and LFCNB. Hemodynamics were stable during the surgery (Tables 1 and 2).
To our knowledge, this is the first report of peripheral nerve block under monitoring with TTE in a patient with HOCM. We subjected our patient to continuous arterial pressure measurement and TTE in addition to the monitoring procedures described in the guidelines of the Japanese Society of Anesthesiology. Although the pulmonary catheter may be useful for circulatory management [12], recent studies point out the invasiveness of this device and the associated risk factors that may worsen patient outcome [13,14,15]. Therefore, we selected TTE for circulatory management in our case. The echocardiographic cardiac output measurements have been reported to be as accurate as thermal dilution according to assessment using a pulmonary arterial catheter, which is the current gold standard for cardiac output measurement [16, 17]. As TTE could enable evaluation of cardiac hemodynamics and morphology, we could diagnose and treat the condition in a timely manner despite the increase in the pressure gradient at the LVOT site or worsening of MR. Although we had evaluated the systolic and diastolic functions, pressure gradient at the LVOT, and degree of MR, these parameters remained unchanged during the surgery (Table 2).
Our patient had previously undergone ICD implantation. The ICD was disabled to avoid malfunction. An external defibrillator was available for use in the event of ventricular tachycardia or ventricular fibrillation [18, 19].
Postoperative pain could increase sympathetic nervous system activity, which could increase the pressure gradient across the LVOT. The combined peripheral nerve blocks contributed to postoperative cardiovascular stability and pain relief. In the early postoperative period, pain relief can be achieved with the peripheral nerve blocks supplemented by non-opioid drugs.