Paige Latham

Use of a Continuous Local Anesthetic Infusion for Pain Management after Median Sternotomy

Background The use of large doses of opioid analgesics to treat pain after cardiac surgery can prolong the time to tracheal extubation and interfere with recovery of bowel and bladder function in the postoperative period. Therefore, the authors investigated the efficacy of a continuous infusion of bupivacaine 0.25% or 0.5%, at the median sternotomy site, for 48 h after cardiac surgery in reducing the opioid analgesic requirement and improving the recovery process. Methods In this prospective, randomized, placebo-controlled, double-blind clinical trial, 36 consenting patients undergoing open-heart surgery with a standardized general anesthetic technique had two indwelling infusion catheters placed at the median sternotomy incision site at the end of surgery. The patients were randomly assigned to receive normal saline (control), bupivacaine 0.25% or bupivacaine 0.5%via an elastomeric infusion pump at a constant rate of 4 ml/h for 48 h. Patients evaluated their chest pain using an 11-point verbal rating scale, with 0 = no pain to 10 = worst pain imaginable. In addition, the postoperative opioid analgesic requirements and opioid-related adverse effects were recorded. Patient satisfaction with their pain management was assessed at specific intervals during the postoperative period using a 100-point verbal rating scale, with 1 = highly dissatisfied to 100 = highly satisfied. Finally, serum bupivacaine concentrations were measured 24 and 48 h after surgery. Results Compared with the control group, there was a statistically significant reduction in verbal rating scale pain scores and patient-controlled analgesia morphine use in the bupivacaine-0.5% group. Patient satisfaction with their pain management was also improved in the bupivacaine-0.5% (vs. control) group. However, there were no significant differences in patient-controlled analgesia morphine use between the bupivacaine-0.25% and control groups. Although the duration of the intensive care unit stay (30 vs. 34 h, respectively) was not significantly decreased, the time to ambulation (1 ± 0.5 vs. 2 ± 1 days, respectively) and the duration of hospital stay (4.2 vs. 5.7 days, respectively) were lower in the bupivacaine-0.5% group than in the control group. Mean ± SD serum bupivacaine concentrations at 48 h in the bupivacaine-0.25% and bupivacaine-0.5% groups were 0.5 ± 0.5 and 1.3 ± 0.7 &mgr;g/ml, respectively. Conclusion A continuous infusion of bupivacaine 0.5% at 4 ml/h is effective for decreasing pain and the need for opioid analgesic medication as well as for improving patient satisfaction with their pain management after cardiac surgery. Patients in the bupivacaine-0.5% group were able to ambulate earlier, leading to a reduced length of hospital stay.

Esophageal Doppler monitor determinations of cardiac output and preload during cardiac operations

BACKGROUND Perioperative management of cardiac surgical patients frequently mandates measurements of cardiac output and left ventricular filling. This study compared cardiac output and left ventricular filling measured by pulmonary artery (PA) catheter and esophageal Doppler monitor (EDM). METHODS Thirty-four patients undergoing coronary artery bypass grafting were prepared by implanting a PA catheter, an EDM, and a transit-time ultrasonic flow probe around the ascending aorta. In 20 patients, left ventricular end-diastolic short-axis area (EDA) was measured by transesophageal echocardiography. At five time points, cardiac output was measured from the flow probe, the EDM, and the PA catheter (by thermodilution), and left ventricular filling was assessed from the PA catheter (as PA diastolic pressure), the EDM (corrected flow time), and the EDA. For cardiac output, concordance correlations relating EDM to flow probe and PA catheter to flow probe were calculated, transformed (Fishers z transformation), and compared by Students t test. For left ventricular filling, regression coefficients were created between corrected flow time and EDA and between PA diastolic pressure and EDA. Spearman correlations were compared by Wilcoxon rank sum test. RESULTS The EDM and the PA catheter exhibited similar relationships to the flow probe (concordance correlations, 0.55 +/- 0.35 [mean +/- standard deviation] and 0.49 +/- 0.34, respectively; p = 0.088). The correlation between corrected flow time and EDA was better than the correlation between PA diastolic pressure and EDA (concordance correlations, 0.49 +/- 0.55 versus 0.10 +/- 0.43, respectively; p < 0.01). CONCLUSIONS These data suggest that the EDM may offer a less invasive technique for evaluating cardiac output and a more accurate estimate for preload compared with the PA catheter.

Fast-track cardiac anesthesia: use of remifentanil combined with intrathecal morphine as an alternative to sufentanil during desflurane anesthesia.

The purpose of this cardiac fast-track study was to evaluate the use of remifentanil (R) combined with intrathecal (IT) morphine as an alternative to sufentanil (S) during desflurane anesthesia with respect to postoperative pain control. Prior to entering the operating room, patients in the R group (n = 20) received morphine, 8 &mgr;g/kg IT. Anesthesia was induced using a standardized anesthetic technique in all patients. In the R group, anesthesia was maintained with R, 0.1 &mgr;g · kg−1 · min−1 in combination with desflurane 3–10%. In the S group (n = 20), patients received S 0.3 &mgr;g · kg−1 · h−1 and desflurane 3–10%. There were no differences between the two groups with respect to time from arrival in the intensive care unit to tracheal extubation (5.1 ± 4.3 h vs 5.8 ± 6.7 h for R and S groups, respectively). After extubation, patients in the R group had significantly lower visual analog pain scores, reduced patient-controlled analgesic requirements, and greater satisfaction with their perioperative pain management, compared with patients in the S group. We conclude that R combined with IT morphine provided superior pain control after cardiac surgery compared with a S-based general anesthetic technique. Implications As part of a cardiac fast-tracking program involving desflurane anesthesia, the use of intrathecal morphine in combination with a remifentanil infusion provided improved postoperative pain control, compared with IV sufentanil alone.

Use of recombinant hirudin in patients with heparin-induced thrombocytopenia with thrombosis requiring cardiopulmonary bypass.

HEPARIN-induced thrombocytopenia (HIT) and heparin-induced thrombocytopenia with thrombosis (HITT) are rare but potentially fatal complications of heparin therapy. 1,2 Administration of heparin in patients with HITT causes platelet aggregation, thromboembolism, and thrombocytopenia. Therefore, an alternative anticoagulant to heparin is recommended in these patients. Recombinant hirudin (r-hirudin; Refludan, Hoechst Marion Roussel, Inc., Kansas City, MO) is a direct thrombin inhibitor that has been used in patients with HIT and HITT, and case reports have described its use as an anticoagulant in patients requiring cardiac surgery The ecarin clotting time (ECT) is probably the best marker for anticoagulation with r-hirudin, 6 but this test is not widely available. Furthermore, little information is available on appropriate dosing for patients with renal insufficiency, obesity, or those requiring prolonged cardiopulmonary bypass (CPB). We describe the use of r-hirudin as an anticoagulant in two patients requiring CPB, the first with normal renal function and the second with renal insufficiency. The different dose regimens and the use of activated partial thromboplastin time (aPTT) for monitoring anticoagulation are discussed.

A gastric laceration after transesophageal echocardiography in a patient undergoing aortic valve replacement.

T ransesophageal echocardiography (TEE) is a low risk procedure frequently used for intraoperative monitoring in patients undergoing cardiac surgery. Daniel et al. (1) demonstrated an 0.18% overall complication rate in 10,419 awake and asleep TEE examinations. Gastrointestinal complications of TEE are rare and have been previously confined to the oropharynx and esophagus (2). There are four cases of esophageal lacerations resulting in gastrointestinal bleeding in the literature (3,4). We report a case of gastric laceration resulting in gastrointestinal bleeding in a patient after intraoperative TEE examination.