Perioperative management of poly-trauma in a postmitral valve replacement patient with severe left ventricular systolic dysfunction.

The anesthetic management of a patient with severe left ventricular (LV) dysfunction undergoing noncardiac surgery poses a challenge to the anesthesiologist as LV dysfunction is commonly complicated by progressive congestive heart failure and malignant arrhythmias. When the cause for LV dysfunction is postvalve replacement, additional complications such as intraoperative thrombosis, bleeding, and infective endocarditis need to be addressed perioperatively. In such situations, the anesthesiologist must have the knowledge hemodynamics, diagnostic evaluations, and treatment modalities, more so regarding various drugs used during anesthesia. We report a case of postmitral valve replaced patient with severe LV dysfunction posted for surgery of fracture of the femur and facial fractures managed successfully during anesthesia.

INTRODUCTION

Perioperative management of patients with severe left ventricular systolic dysfunction (LVSD) can pose a great challenge for the anesthesiologist. Various etiological factors are implicated in LVSD, most common being ischemic heart disease, dilated cardiomyopathy, and idiopathic cardiomyopathy. There exists a great amount of literature about management of LVSD in these conditions perioperatively.[1] But, LVSD due to valvular heart disease is not as common. The important goal in these patients is to maintain sinus rhythm and prevent myocardial depression[2] which is difficult to achieve in view of preexisting atrial fibrillation (AF) and anticoagulation therapy in patients with LVSD due to valvular heart disease. Here, we report successful management of a case of postmitral valve replacement (MVR) patient with severe LVSD with ejection fraction (EF) of 20% who came for femur nailing and open reduction and internal fixation (ORIF) of facial fractures.

CASE REPORT

A 50-year-old Indian male was admitted with a history of road traffic accident. He was a known case of rheumatic heart disease since the age of 30 years and had undergone a successful MVR surgery 11 years back. He had sustained fracture of the shaft of right femur [Figure 1] and left zygoma, floor of the orbit and left maxilla [Figure 2]. He was scheduled for closed reduction intramedullary nailing of right femur with ORIF of facial fracture. He had no other co-morbidity. His history revealed that prior to the valve replacement; he was in New York Heart Association class IV breathlessness which improved to class III after valve replacement. Prior to the trauma, his effort tolerance was poor; he was only able to walk 300–500 m on level ground without any symptoms of palpitations, fatigue, chest pain or breathlessness. He was receiving oral warfarin 3 mg, digoxin 0.25 mg, enalapril 2.5 mg once daily.

Figure 1

Fracture shaft of the femur

Figure 2

Facial fracture

Physical examination revealed an irregularly irregular pulse, 90 beats/min and blood pressure of 120/70 mm of Hg. His JVP was raised, and other systemic examination did not reveal any abnormality. Patient's electrocardiogram showed AF with a heart rate of 100/min. The chest X-ray revealed cardiomegaly, mitral valve prosthesis, sternotomy sutures [Figure 3]. His echocardiogram showed poor biventricular function (EF 20%, global hypokinesia), pulmonary artery pressure of 75 mm of Hg, mild tricuspid regurgitation, no paravalvular leak and absence of vegetations and no left atrium clots. Renal and liver functions were within normal limits. Warfarin was stopped, and he was put on low molecular weight heparins (LMWH) 0.6 ml twice a day. On the 4th day, his INR was stabilized at 1.2, and it was decided to proceed with the scheduled surgery. On the day of the surgery, the morning dose of low molecular weight fraction was skipped, and he was shifted to the operation theater. Two units of packed red blood cells, fresh frozen plasma, platelets, and protamine were reserved for emergency use in case of undue blood loss during the surgery. Patient received ampicillin 1.5 g and gentamicin 80 mg intravenously as infective endocarditis prophylaxis 30 min prior to skin incision. Case was managed by a team of cardiac and general anesthesiologists. Apart from the standard monitoring, invasive blood pressure monitoring and central venous pressure monitoring were also instituted. In view of the surgery involving oro fascial area, trans-esophageal echocardiography (TEE) monitoring was not used. Injection dobutamine 5 mcg/kg/min and injection noradrenaline 0.05 mcg/kg/min were started before inducing the patient. Patient was then induced with midazolam 2 mg, fentanyl 250 mcg, thiopentone sodium 100 mg and vecuronium 8 mg. Nasotracheal intubation was done with the help of 7.5 size Portex endotracheal tube. Anesthesia was maintained with the help of 50% oxygen in the air, sevoflurane (1–2%) and intermittent bolus of vecuronium 1 mg and 25 mcg of fentanyl. The operation blood loss was 500 ml which was replaced with one unit of packed red blood cells and crystalloids. Total duration of the surgery was 7 h and hemodynamics were well-maintained throughout the procedure. At the end of the procedure, patient was shifted to postanesthesia care unit and ventilated for 2 h. Once his core body temperature returned to normal and ABG showed acceptable PaO2 and PaCO2, normal results, neuromuscular block was reversed with neostigmine and glycopyrrolate and he was extubated. He was restarted on LMWH 0.6 mg from the evening of surgery and the next day morning, he was also started on warfarin. By 4th day the INR was 2.2, LMWH was stopped and warfarin continued. An echocardiogram done at the time of discharge revealed normally functioning valves with no clot or vegetation. He was discharged from the hospital after 2 weeks without any sequelae.

Figure 3

Chest X-ray pa view

DISCUSSION

The present case had three major problems, severe biventricular systolic dysfunction (EF 20%), prosthetic mitral valve and prolonged surgical procedure (7 h) with associated hemodynamic and intravascular volume changes. The goals for anesthetic management were prevention of thrombosis, prevention of infective endocarditis, adequate analgesia, avoidance of drug-induced myocardial depression, maintenance of normo-volemia, and prevention of increased ventricular afterload.[3]

Surgery in patients with prosthetic heart valve is like a double-edged sword, where the risk of thrombosis has to be balanced against the risk of hemorrhage. There are no large randomized studies that compare different perioperative anticoagulant regimens for patients with mechanical heart valves undergoing surgery. Because of the high risk of hemorrhage, the INR should be within the normal range before the procedure which can be accomplished by stopping warfarin. To minimize the risk of thrombosis in patients with prosthetic heart valves, both the European Society of Cardiology and the Fourth American College of Chest Physicians Consensus on Antithrombotic Therapy have recommended perioperative heparinization.[4]

Perioperative management

In the case of elective surgeries, it is advisable to optimize medical treatment for heart failure achieves medical control of heart failure for at least a week's duration. But in emergency/semi-emergency cases there would be no time to optimize the heart failure. In such cases, any arrhythmia should be appropriately treated. If the patient is already in AF, rate control is very important and this can be achieved with drugs and by correcting the electrolyte imbalance; hypokalemia and hypomagnesemia should be corrected (both of which are likely to be depleted in patients receiving chronic diuretic therapy). This is especially important in relation to potassium and magnesium ions.[5] It is essential to assess the degree of biventricular impairment and valvular dysfunction by echocardiography. Whenever feasible and possible, consideration should be given to the use of regional or local anesthesia. Regional anesthesia used alone or in combination with general anesthesia has the advantage of reducing the after load which can improve cardiac output.[6] However, hypotension must be prevented to avoid myocardial hypo-perfusion. Treatment of arterial pressure changes should be considered if >10% decrease in systolic pressures occurs. Inodilators and/or vasopressors are to be used to maintain hemodynamic stability.

Invasive hemodynamic monitoring using direct arterial pressure and central venous pressure is indicated in unstable patients, prolonged surgical procedure, especially in an emergency situation. Intraoperative TEE is recommended for examining dynamic changes in cardiac performance and the response to inotropes and fluid loading. In our case, it could not be used in view of oro-maxillary surgery. During anesthesia, avoidance of tachycardia is an additional goal. Inotropic support if required during and after surgery can be provided by the use of a variety of agents including dobutamine, dopamine, phosphodiesterase inhibitors, and levosimendin. It may be necessary to counteract some of the peripheral vasodilator effects of general anesthetic agents to assist coronary perfusion. This is achieved with the cautious use of norepinephrine which increases systemic vascular resistance and maintains mean arterial pressure.[3] Hence, small doses of dobutamine and noradrenaline were used in this case was to improve biventricular function. Prevent further increase in pulmonary pressure and support the circulation if hypotension occurred, in view of compromised cardiac status of the patient.

Extubation should be as smooth as intubation. It should be attempted only when the patient is hemodynamically stable, the core body temperature has returned to normal and electrolytes and ABG are within normal limits.

CONCLUSION

The main purpose of presenting this case is to emphasize the need for special attention toward maintaining stable rhythm and anticoagulation in patients with LVSD due to valvular heart disease. This is in addition to other factors like thorough preoperative assessment, optimizing the cardiac status, proper anesthetic plans, intraoperative and postoperative monitoring and prompt diagnosis, and management of complications.