Gemma Hayeck

Comparison of central venous to mixed venous oxygen saturation in patients with low cardiac index and filling pressures after coronary artery surgery.

OBJECTIVE To evaluate the correlation and agreement between mixed venous oxygen saturation (SvO(2)) and central venous oxygen saturation (ScvO(2)) in patients with low cardiac index and filling pressures after coronary artery surgery. DESIGN Prospective observational study. SETTING Tertiary care academic hospital. PARTICIPANTS Sixty consecutive patients with a cardiac index <2 L/min/m(2) and a pulmonary artery occlusion pressure <12 mmHg after coronary artery surgery were included. INTERVENTIONS Patients were monitored by a pulmonary artery catheter and a central venous catheter positioned in the superior vena cava. MEASUREMENTS AND RESULTS SvO(2) and ScvO(2) were simultaneously measured before (T0) and after (T1) normalization of the cardiac index (>2.5 L/min/m(2)) by fluid therapy. Sixty pairs of measures were obtained at T0 and at T1. Bias between SvO(2) and ScvO(2) was -0.6% (T0) and -0.8% (T1). Limits of agreement were from -19.2% to 18% (T0) and from -15.6% to 14% (T1), and the correlation coefficient was 0.463 (T0) and 0.72 (T1). SvO(2) and ScvO(2) changes from T0 to T1 (DeltaSvO(2) and DeltaScvO(2)) were calculated. The bias between DeltaSvO(2) and DeltaScvO(2) was -0.25. Limits of agreement were from -20% to 19.5%, and the correlation coefficient was 0.6. CONCLUSIONS In patients with low cardiac index and filling pressures after coronary artery surgery, ScvO(2) could not be used as a direct alternative for SvO(2). After fluid therapy and normalization of the cardiac index, differences between individual values remained large, and the disagreement between ScvO(2) and SvO(2) changes was significant.

Postoperative oral amiodarone versus oral bisoprolol as prophylaxis against atrial fibrillation after coronary artery bypass graft surgery: A prospective randomized trial

BACKGROUND Postoperative atrial fibrillation (AF) occurs in up to 50% of patients undergoing coronary artery bypass (CABG) surgery and is associated with complications. Amiodarone and beta blockers are effective as prophylaxis for AF after CABG. The purpose of this study was to compare oral amiodarone versus oral bisoprolol for prevention of AF after CABG. METHODS In this randomized study, 200 patients admitted for elective CABG were given oral amiodarone (n=98 patients) or oral bisoprolol (n=102 patients) beginning 6 h after surgery. Amiodarone patients received 15 mg/Kg then 7 mg/Kg/day for one month. Bisoprolol patients received 2.5 mg then 2.5 mg bid indefinitely. RESULTS Postoperative AF occurred in 15.3% of the patients in the amiodarone group and 12.7% of the patients in the bisoprolol group (p=0.60). Maximal ventricular rate tended to be lower in the bisoprolol group (125+/-6 beats/min) compared with the amiodarone group (144+/-7 beats/min, p=.06). Preoperative beta blockage did not affect AF incidence in either study group. There was no difference between the 2 groups for the onset time of AF episodes, total AF duration, AF recurrence and postoperative length of hospital stay. No serious postoperative complications occurred in the two study groups. Two reversible low cardiac output cases occurred with bisoprolol. CONCLUSIONS Postoperative oral bisoprolol and amiodarone are equally effective for prophylaxis of AF after CABG. Treatment with bisoprolol resulted in a trend to lower ventricular response rate in AF cases. Both regimens were well tolerated.

Can Femoral Artery Pressure Monitoring Be Used Routinely in Cardiac Surgery

OBJECTIVE The purpose of this study was to evaluate the safety of femoral arterial pressure monitoring in cardiac surgery. DESIGN Prospective, observational study. SETTING Cardiac surgery unit (CSU) in a university hospital. PARTICIPANTS Of a total of 2,350 consecutive patients scheduled for elective cardiac surgery with cardiopulmonary bypass, 2,264 patients with femoral artery pressure monitoring were included. INTERVENTIONS A femoral arterial catheter was inserted percutaneously before the induction of anesthesia. The catheter was withdrawn 40 to 96 hours after surgery. It was replaced by a radial artery catheter in patients staying for more than 4 days in the CSU or in case of pulse loss or lower limb ischemia. The catheter was removed and sent for cultures whenever it showed local changes, discharge, or if sepsis was suspected. MEASUREMENTS AND MAIN RESULTS Pain on insertion ranged from 0 to 20 mm on the 100-mm visual analog scale. Complications related to femoral artery cannulation were recorded. No cases of femoral artery thrombosis, lower extremity ischemia, or hematoma requiring surgery were noted. Small hematomas were observed in 3.3% of patients. The incidence of oozing was 2.1% after the insertion of the catheter and 4.9% after its removal. Three cases (0.13%) of serious bleeding occurred; 2 required surgery. Eight percent of catheter tips were sent for culture, and positive bacterial growth was recorded in 18.6% of them. Catheter-related blood stream infection occurred in 0.5% of the total patient population included. CONCLUSIONS Femoral artery pressure monitoring was associated with a low complication rate and, therefore, it can be used routinely in cardiac surgery.

Generalized Skin Mottling: An Early Sign of Acute Mesenteric Infarction After Cardiac Surgery

To the Editor: Acute mesenteric infarction after cardiac surgery is uncommon (0.1%-0.3%) but associated with a very high mortality rate (60%-90%).1-3 Early diagnosis is of critical importance in patients with mesenteric infarction because the only chance of cure is prompt surgical intervention.4 However, critically ill patients after cardiac surgery are often ventilated and sedated, and, therefore, signs and symptoms of abdominal pathology are masked. The difficulty in making the diagnosis of mesenteric infarction after cardiac surgery contributes heavily to its catastrophic mortality. We are reporting the cases of 2 cardiac surgery patients who presented generalized skin mottling as an early clinical sign of postoperative acute mesenteric infarction. The first patient was a 73-year-old man with a medical history of heavy smoking, hyperlipidemia, and cerebral vascular disease. He had an uneventful triple-vessel revascularization with extracorporeal circulation and was transferred to our intensive care unit under deep sedation and mechanical ventilation. On admission, the patient had generalized skin mottling characterized by unevenly distributed colored areas of different shades all over the lower limbs, the abdomen, and the thorax. Physical examination was negative. Hemodynamic parameters, urine output, arterial and mixed venous blood gases, standard bicarbonate, and lactate were within normal limits. After tracheal extubation at the 8th postoperative hour, the patient complained of abdominal pain progressively associated with oliguria and metabolic acidosis. The diagnosis of mesenteric ischemia was confirmed by an abdominal computed tomography scan and colonoscopy showing ischemic changes in the colon. An emergency laparotomy showed diffuse necrosis of the large intestine. The patient had a total colon resection with end ileostomy but died on the 4th postoperative day as a result of multiple-organ failure. The second patient was an 84-year-old man with a medical history of chronic renal failure and diabetes who had an uneventful mitral and aortic valves replacement. He presented in the immediate postoperative period with generalized skin mottling with no other clinical, hemodynamic, or metabolic disorder. After extubation, on day 1, the patient showed peritonitis signs associated with dramatic increases in leukocyte count, arterial lactate, and serum amylase. An exploratory laparotomy revealed massive necrosis of the small and large intestine. The patient had a subtotal bowel resection with stoma. He died on the 11th postoperative day as a result of sepsis. In critically ill patients, skin mottling is a clinical sign of vasoconstriction and tissue hypoperfusion. Mottling was reported as one of the presenting symptoms in 46% of patients from a general population undergoing surgery for mesenteric infarction.5 It is caused by the release of vasoactive products from the ischemic intestinal mucosa. These cases show that generalized skin mottling might be an early sign of mesenteric infarction in ventilated and sedated patients after cardiac surgery. It appeared several hours before abdominal clinical signs, hemodynamic deterioration, and metabolic acidosis. We conclude that mesenteric infarction should be suspected in sedated patients with generalized skin mottling after cardiac surgery. Patients presenting with this clinical sign should be woken up rapidly so that abdominal symptoms can be accurately evaluated and further diagnostic investigations undertaken.

Hemodynamics With Postoperative Pacing

the carotid artery indeed needed surgical intervention.7 Ultrasound guidance for the placement of central catheters has increased in operating rooms. It is a very helpful tool in placing central venous catheters. However, as this case shows, ultrasound can further be useful in managing the complications such as accidental carotid artery punctures. The intimal tear with a pseudoaneurysm, which may not have been recognized from external examination alone, can be identified quickly and assessed by using ultrasound. Routine ultrasound examination of the carotid artery after its accidental puncture should be encouraged.