Anne Ducart

Microcirculatory Alterations in Cardiac Surgery: Effects of Cardiopulmonary Bypass and Anesthesia

BACKGROUND Heterogeneity in microvascular perfusion is associated with impaired tissue oxygenation. We hypothesized that cardiac surgery with or without cardiopulmonary bypass (CPB) could induce microvascular alterations. METHODS We used an orthogonal polarization spectral imaging technique to evaluate the sublingual microcirculation in patients undergoing cardiac surgery with (n = 9) or without (n = 6) CPB. We also included, as a control group, 7 patients undergoing thyroidectomy with the same anesthetic procedure. Hemodynamic and microcirculatory variables were obtained the day before surgery, after induction of anesthesia, during CPB, on admission to the intensive care unit or the recovery room, and 6 and 24 hours after the end of the surgical procedure. Data are presented as median (25th to 75th percentile). RESULTS No differences in hemodynamic variables were observed between the two cardiac surgery groups. The proportion of perfused vessels was similar in all three groups at baseline (89% [87% to 90%]), and decreased similarly after induction of anesthesia to 71% (69% to 74%). It decreased further during CPB to 53% (50% to 56%). On admission to the intensive care unit or recovery room, alterations were more severe in CPB than in off-pump patients (60% [59% to 62%] versus 64% [61% to 65%]; p = 0.03), whereas they had already normalized in thyroidectomy patients (89% [86% to 90%]; p = 0.0005 versus cardiac surgery). In both cardiac surgery groups these microcirculatory alterations decreased with time, but persisted at 24 hours. The severity of microvascular alterations correlated with peak lactate levels after cardiac surgery (y = 11.5 - 0.15x; r(2) = 0.65; p < 0.05). CONCLUSIONS Microcirculatory alterations are observed in cardiac surgery patients whether or not CPB is used. Anesthesia contributes to these alterations, but its effects are transient.

Different Anesthetic Techniques Associated with Different Incidences of Chronic Post-thoracotomy Pain: Low-Dose Remifentanil Plus Presurgical Epidural Analgesia is Preferable to High-Dose Remifentanil with Postsurgical Epidural Analgesia

OBJECTIVE To investigate the relationships between 2 anesthetic techniques, or the extent of allodynia around the surgical wound, and the occurrence of chronic post-thoracotomy pain. DESIGN Prospective, randomized study. SETTING A single-institution, university hospital. PARTICIPANTS Thirty-eight patients who underwent elective thoracotomy under general anesthesia. INTERVENTIONS High-dose remifentanil (average effect-site concentration 5.61 +/- 0.84 ng/mL) with epidural analgesia started and at the end of surgery or low-dose remifentanil (average effect site concentration 1.99 +/- 0.02 ng/mL) with epidural analgesia with 0.5% ropivacaine started at the beginning of anesthesia. MEASUREMENTS AND MAIN RESULTS Pain intensity and the extent of allodynia around the wound were measured during the hospital stay. The presence and intensity of residual pain were assessed 1, 3, and 6 months after surgery and at the end of the study (6-13 months, average 9 months). A DN4 neuropathic pain diagnostic questionnaire was conducted at the same times. In the high-dose group, the area with allodynia was three times larger than the area in the low-dose group. The increased allodynia was associated with a higher incidence of chronic pain (RR: 2.7-4.2) 3 and 6 months after surgery and at the end of the study (median follow-up: 9.5 months). CONCLUSIONS High-dose remifentanil (0.14-0.26 microg/kg/min) without epidural analgesia during surgery is associated with a large area of allodynia around the wound. These patients develop a much higher incidence of chronic pain than those receiving low-dose remifentanil with epidural analgesia during surgery.

Hemodynamic benefit of optimizing atrioventricular delay after cardiopulmonary bypass.

BACKGROUND Shortening of atrioventricular delay (AVD) by sequential cardiac pacing has been proposed to improve hemodynamics in patients with end-stage heart failure. In addition, optimization of prolonged AVD may be associated with a decrease of presystolic mitral insufficiency. The aim of this study was to explore the incidence of prolonged AVD during the early postcardiopulmonary bypass (CPB) period and to evaluate the hemodynamic benefit of its shortening by using sequential cardiac pacing. METHODS Fifty consecutive patients scheduled for coronary artery bypass grafting were prospectively screened. AVD was measured immediately after separation from CPB. Patients presenting with AVD greater than or equal to 200 ms entered the study. Sequential cardiac pacing was introduced with programmed AVD starting at 80 ms and randomly increased by steps of 20 ms until resumption of native anterograde atrioventricular node conduction. Cardiac index (CI) was derived from transesophageal echocardiographic data during each step of this procedure. RESULTS Nineteen patients were included. Median native AVD was 220 ms. Median optimal AVD was 140 ms. Mean native CI (CI-nat) was 2.59 +/- 0.42 L/min/m2. Mean optimal CI (CI-opt) was 3.12 +/- 0.45 L/min/m2. CI-opt/CI-nat was 1.20 +/- 0.07. CI-opt/CI-nat was significantly inversely correlated with preoperative left ventricular ejection fraction (r = -0.83). CONCLUSIONS Prolonged AVD is a common occurrence after CPB. Its artificial shortening by sequential cardiac pacing is always associated with a significant increase of CI. The magnitude of this hemodynamic improvement is inversely correlated with preoperative left ventricular ejection fraction.

Propofol-induced anaphylactoid reaction during anesthesia for cardiac surgery.

A 51-year-old man with a history of unstable angina was scheduled for CABG surgery. He had no history of a prior general anesthetic or allergies. He sustained a Q-wave inferior myocardial infarction 12 years ago, and his ejection fraction was 54%. Current medications were nisoldipine, 5 mg, a calcium channel blocker; celiprolol, 200 mg, a P-blocker; and md the peak inspiratory pressures were normal. Intravenous epinephrine was administered at a dose of 200 pg, repeated 1 minute later, and followed by a continuous infusion at a rate of 0.2 pg/kg/min. The propofol infdsion was then stopped. In addition, hemodynamic stabilization required volume loading with crystalloids and the percutaneous placement of an intraaortic balloon pump. Isoflurane was gradually introduced with midazolam and a continuous infusion of morphine to replace the anesthetic drugs used during the induction. As the hemodynamics improved, epinephrine was progressively reduced and discontinued over 90 minutes. The surgical procedure was uneventful. Weaning hrn cardiopulmonary bypass was possible without inotropes. Extubation was performed 8 hours

Doppler-derived left ventricular rate of pressure rise and inotropic requirements during mitral valve surgery.

BACKGROUND The estimation of left ventricular (LV) contractility is difficult in the presence of significant mitral regurgitation (MR). Prediction of LV performance after MR repair is even more problematic. The intraoperative Doppler-derived LV rate of pressure rise (LV delta P/delta t) analyzed before cardiopulmonary bypass (CPB) was presumed to be a useful predictive parameter for LV performance. Therefore, its relation to perioperative inotropic requirements (PIR) necessary for separation from CPB after surgical MR repair was investigated. METHODS Twenty-eight patients scheduled for surgical MR repair fulfilled the selection criteria. Pre-CPB LV delta P/delta t, pre-CPB echocardiographic LV fractional area change (LV FAC), and pre-CPB thermodilution-derived cardiac index (CI) were recorded. After MR repair, separation from CPB was performed with regard to standardized guidelines. PIR during the first 60 minutes following separation were recorded. RESULTS Pre-CPB LV delta P/delta t could be assessed in 22 patients. Pre-CPB LV delta P/delta t was 882 +/- 450 mmHg/sec, pre-CPB LV FAC was 49% +/- 9%, and pre-CPB CI was 2.0 +/- 0.2 L/kg/min. Pre-CPB LV delta P/delta t was significantly correlated with pre-CPB LV FAC (r = 0.56), and with pre-CPB CI (r = 0.72). Inotropic support was necessary in 16 patients (73%), and was best predicted by the pre-CPB LV delta P/delta t, by means of logistic regression (p = 0.026). CONCLUSIONS Doppler-derived LV delta P/delta t was assessable in most patients with severe chronic MR, and was the best intraoperative predictive parameter of post-CPB inotropic requirements after surgical MR repair.

Tocopherol in lipoproteins and blood cells after cardiac surgery.

Abstract: Cardiac surgery was associated with a marked reduction in circulating LDL and HDL particles, which in turn largely affectd α‐toc transport. α‐toc was decreased in WBCs but not in PLTs and RBCs. An increased hydroperoxide content was observed in LDL and possibly in HDL after cardiac surgery.

Regional increment in myocardial reflectivity after aortic valve replacement: early detection of air and assessment of treatment by transesophageal echocardiography.

IR EMBOLISM during cardiac surgery is a common occurrence and may be responsible for neurologlc and cardiac complications. This case report illustrates how transesophageal echocardiography (TEE) showed the regional increment in myocardial reflectlvity secondary to coronary air embolism and how TEE momtoring aided in detecting the efficacy of maneuvers to remove the air. CASE REPORT A 56-year-old man was scheduled for an aortic valve replacement. He had a history of severe aortic valvular stenosis with a mean transaortlc gradient of 56 mmHg and an aortic valve area of 0.63 cm 2. Coronary angiogram was normal with a left ventricular ejection fraction of 60%. After induction of anesthesia, a multiplane TEE probe, operating at 5 mHz, connected to an echocardiographlc system (Hewlett Packard SONOS 1000; Andover, MA), was inserted in a routine manner. After cross-clamping of the ascending aorta, anterograde cold hyperkalemic cardioplegia was administered, followed by intermittent retrograde cold hyperkalemic cardioplegia. Cardiopulmonary bypass (CPB) was performed under mild systemic hypothermia (34.8°C). The aortic valve was replaced by a mechanical prosthetic valve (St Jude 23 ram). Before unclamping of the aorta, passive filling of the left ventricle (LV), venting through a needle inserted in the ascending aorta and manual inflation of the lungs were performed with the patient head down. The passive filling was still low, and the accumulated air in the heart was not detected by TEE at that time. Immediately after unclamping of the aorta, the TEE detected microbubbles coming from the left atrium and massively from the right pulmonary veins. Although the venting was maintained, with the heart beating, an abrupt increase in myocardial reflectivity was observed (Fig 1). This myocardial opacification involved right ventricular and septal walls and was followed by significant ST-segment elevation in inferior leads on the electrocardiogram (ECG) (Fig 2). Severe depression of the regional LV function occurred, followed by severe distention of the LV cavity and by refractory ventricular fibrillation. It was decided to clamp the ascending aorta again in order to avoid systemic air embolism and to administer crystalloid retrograde cardioplegia (300 mL) to eliminate the intracoronary air, while the heart was manipulated in