Mark Buckland

A Comparison of Epidural Ropivacaine Infusion Alone and in Combination with 1, 2, and 4 [micro sign]g/mL Fentanyl for Seventy-Two Hours of Postoperative Analgesia After Major Abdominal Surgery

UNLABELLED Our aim in this prospective, randomized, double-blinded study was to compare the analgesic effectiveness and side effects of epidural infusions with ropivacaine 2 mg/mL alone (Group R; n = 60) and in combination with fentanyl 1 microg/mL (R1F; n = 59), 2 microg/mL (R2F; n = 62), and 4 microg/mL (R4F; n = 63) for up to 72 h after major abdominal surgery. Effective epidural neural blockade was established before surgery; postoperatively, the infusion rate was titrated to a maximum of 14 mL/h for analgesia. No additional analgesics other than acetaminophen were permitted during the infusion. The median of individual visual analog scale score with coughing were <20 mm for all groups (0 = no pain, 100 = worst pain) and was significantly lower (P < 0.01) for Group R4F at rest and with coughing (compared with Group R). Infusions were discontinued due to inability to control pain in significantly fewer patients in Group R4F (16%) than the other groups (34% to 39%; P < 0.01). For all groups, >90% of patients had no detectable motor block after 24 h. Hypotension, nausea, and pruritus were more common with the larger dose of fentanyl. We conclude that, after major abdominal surgery, an epidural infusion of ropivacaine 2 mg/mL with fentanyl 4 microg/mL provided significantly more effective pain relief over a 3-day period than ropivacaine alone or ropivacaine with lower concentrations of fentanyl. IMPLICATIONS Postoperative epidural analgesic infusions are widely used, but there is little information regarding optimal strengths of opioid with local anesthetic. In this blinded, prospective study, we compared four different epidural infusion solutions for efficacy and side effects over a clinically useful postoperative period and conclude that an epidural infusion of ropivacaine 2 mg/mL with fentanyl 4 microg/mL was most effective.

Remifentanil, Fentanyl, and Cardiac Surgery: A Double-blinded, Randomized, Controlled Trial of Costs and Outcomes

Remifentanil may be beneficial in patients undergoing coronary artery bypass graft surgery, by promoting hemodynamic stability, reducing drug requirements, and attenuating the neurohumoral “stress response.” We enrolled 77 cardiac surgical patients in a double-blinded, randomized trial and randomly allocated them to one of three groups: remifentanil infusion at 0.83 &mgr;g · kg−1 · min−1 (Group R); fentanyl bolus, small dose, at 12 &mgr;g/kg (Group FLD); and fentanyl bolus, moderate dose, at 24 &mgr;g/kg (Group FMD). We found a significant difference in the median time to tracheal extubation: Group FLD, 6.5 h; Group R, 7.3 h; and Group FMD, 9.7 h (P = 0.025). Group R patients had similar times to those of Groups FLD (P = 0.14) and FMD (P = 0.30). Group FLD patients had a longer length of hospital stay (P = 0.030). Patients in Group R had a significantly infrequent rate of hypertension but a frequent rate of hypotension (P < 0.01). The urinary cortisol excretion was larger in Group FLD patients (P < 0.0005), and urine flow was smaller (P < 0.0005). Remifentanil was associated with a propofol dose reduction (P = 0.0005) and a concomitant higher bispectral index (P = 0.032). Three Group FLD patients, but none in groups FMD and R, had postoperative myocardial infarctions (P = 0.032). Remifentanil has larger drug acquisition costs but does not increase the total hospital costs associated with cardiac surgery.

Hemodynamic effects, myocardial ischemia, and timing of tracheal extubation with propofol-based anesthesia for cardiac surgery

Recent interest in earlier tracheal extubation after coronary artery bypass graft (CABG) surgery has focused attention on the potential benefits of a propofol-based technique. We randomized 124 patients (34 with poor ventricular function) undergoing CABG surgery to receive either a propofol-based (5 mg [center dot] kg-1 [centered dot] h-1 prior to sternotomy, 3 mg [center dot] kg-1 [center dot] h (-1) thereafter; n = 58) or enflurane-based (0.2%-1.0%, n = 66) anesthetic. Induction of anesthesia consisted of fentanyl 15 micro g/kg and midazolam 0.05 mg/kg intravenously in both groups. The enflurane group received an additional bolus of fentanyl 5 micro g/kg prior to sternotomy and fentanyl 10 micro g/kg with midazolam 0.1 mg/kg at commencement of cardiopulmonary bypass (CPB). Patients receiving propofol were extubated earlier (median 9.1 h versus 12.3 h, P = 0.006), although there was no difference in time to intensive care unit (ICU) discharge (both 22 h, P = 0.54). Both groups had similar hemodynamic changes throughout (all P > 0.10), as well as metaraminol (P = 0.49) and inotrope requirements (P > 0.10), intraoperative myocardial ischemia (P = 0.12) and perioperative myocardial infarction (P = 0.50). The results of this trial suggest that a propofol-based anesthetic, when compared to an enflurane-based anesthetic requiring additional dosing of fentanyl and midazolam for CPB, can lead to a significant reduction in time to extubation after CABG surgery, without adverse hemodynamic effects, increased risk of myocardial ischemia or infarction. (Anesth Analg 1997;84:12-9)

Techniques and Results in Bilateral Sequential Single Lung TranspIantation

Lung transplantation continues to evolve as a therapeutic option for patients with end‐stage lung disease. Bilateral sequential single lung transplantation (BSSLTx) is a recent addition to the lung transplant surgeons armamentarium that incorporates the benefits of single lung transplantation in patients who require double lung replacement while avoiding the morbidity inherent in the en bloc double lung transplant procedure. Between November 1992 and October 1993, 17 recipients underwent 18 bilateral BSSLTx procedures for a variety of indications. In 53% of patients, the procedure was completed without the requirement for cardiopulmonary bypass. Telescoping of the bronchial anastomosis has proved satisfactory. Induction cytolytic therapy has not been utilized. Patients received methyl prednisolone from day 1 and as maintenance prednisolone therapy. Actuarial 1‐year survival is 87%; 12 of the 15 survivors are In Functional Class 1. BSSLTx is an evolving transplant option for patients who require double lung replacement. Definitive clinical diffusion of the procedure will depend upon intermediate and long‐term outcomes for specific recipient pathologies. (J Card SUrg 1994;9:1–14)

Long-term outcomes of cadaveric lobar lung transplantation: Helping to maximize resources

BACKGROUND Cadaveric lobar lung transplantation (CLLTx) represents a potential opportunity to address the bias against smaller recipients, especially children, on transplant waiting lists. The widespread use of CLLTx is hindered by the paucity of outcome data with respect to early complications and long-term lung function and survival. METHODS We looked at the long-term outcomes in 9 patients undergoing CLLTx since May 2003, including early surgical complications, pulmonary function tests, and survival. Patients were analyzed by whether the decision to perform CLLTx was elective (made at the time of listing) or emergent (surgical decision). RESULTS The incidence of early complications in the entire group was low, with the most common being atrial arrhythmias and prolonged thoracostomy tube. Lung function at 1 and 2 years (mean forced expiratory volume in 1 second % predicted +/- standard deviation of 73 +/- 18 and 60.5 +/- 27, respectively) was equivalent to living lobar transplant results. Overall survival was similar to 199 patients who received conventional cadaveric LTx during the same period. CONCLUSION This study suggests that CLLTx has a low complication rate with acceptable lung function and long-term survival, especially in cases where consideration has been given to CLLTx at the time of listing. CLLTx warrants consideration more often for patients of smaller physique to improve their chance of receiving LTx.

Anesthesia for bilateral sequential lung transplantation: Experience of 64 cases

OBJECTIVES To review the experience of anesthesia for bilateral sequential lung transplantation (BSLTx) and describe factors associated with outcome. DESIGN Case series. SETTING University hospital. PARTICIPANTS Sixty-four adult patients undergoing BSLTx. INTERVENTIONS Descriptive and inferential statistical analysis. MEASUREMENTS AND MAIN RESULTS Details of anesthetic technique, patient, and perioperative characteristics are presented. Mean (SD) lung allograft ischemic times were 320 (81) minutes for the first lung and 446 (93) minutes for the second lung. Mean (SD) duration of surgery was 8.5(2) hours, and median time to extubation was 28 hours. There was a reduction in the use of cardiopulmonary bypass, from 10 of 19 (53%) in 1992 to 1993 to 10 of 45 (22%) in 1994 to 1996, p = 0.016. There was an association between time to extubation and duration of surgery (Spearman rank correlation, p = 0.33, p = 0.008), but no association with intraoperative fluid administration (p = 0.18, p = 0.16), or inotrope requirements (p = 0.06, p = 0.65). Predictors of in-hospital mortality were preoperative renal impairment (p = 0.034), early reoperation (p = 0.005), and delay in extubation (p = 0.013); and for 12-month mortality was patient age (p = 0.01). The actuarial survival rates were 90%, 73%, and 58% at 30 days, 1 year, and 2 years, respectively. CONCLUSIONS Anesthesia for BSLTx is a most challenging procedure, for which maintenance of tissue oxygenation and right ventricular perfusion are essential. Recent advances include use of inhaled nitric oxide, ventilator management that reduces dynamic hyperinflation, and permissive hypercapnia. Analysis of outcome from a large case series such as this enables the anesthesiologist to be more aware of the important features of anesthesia for BSLTx, as well as identify potential areas of improvement.

Mitral valve replacement via a right mini-thoracotomy in the dog: use of carbon dioxide to reduce intracardiac air.

OBJECTIVE To develop a clinically applicable method of minimally invasive mitral valve replacement (MVR) with cardioplegia, and examine the ability of carbon dioxide (CO2) to improve de-airing. METHODS MVR was performed via a 5 x 3-cm right lateral minithoracotomy in eight greyhounds. Peripheral cardiopulmonary bypass and an ascending aortic balloon catheter (endoaortic clamp) were used for cardioplegia and aortic root venting. The endoaortic clamp was inflated in the ascending aorta under fluoroscopy and cardioplegic solution was infused. In four dogs, CO2 at 2 l/min was used to displace air in the chest. A left atriotomy was made, the valve exposed and a mechanical valve implanted. After left atrial closure, retained intracardiac gas was aspirated from the aortic root and collected in a bubble-trap. The endoclamp was deflated and the animal weaned from bypass. RESULTS A satisfactory MVR was performed in all cases. The clamp time was 64 +/- 13 min and all dogs were stable post-bypass. In the CO2 group, intrathoracic CO2 was maintained above 86% and 0.1 +/- 0.1 ml of gas was collected, compared to 1.3 +/- 0.8 ml in the non-CO2 group (P < 0.05). CONCLUSIONS Femoro-femoral bypass and use of the endoaortic clamp allow a safe and efficacious MVR via a right minithoracotomy in the dog. A high intrathoracic CO2 concentration reduces the amount of retained intracardiac gas.

Buying time: The use of extracorporeal membrane oxygenation as a bridge to lung transplantation in pediatric patients.

To describe our experience to date of four children with end‐stage lung disease who have been bridged with ECMO to successful lung transplantation in our institution. Between March 2006 and June 2012, a total of 21 pediatric patients successfully underwent lung transplantation within The Alfreds lung transplantation program. This included four children who were bridged on ECMO prior to transplantation according to the “ECMO bridge to transplant” protocol and whose clinical notes and outcomes were reviewed. Lung transplantation is an established life‐saving treatment for patients with severe lung disease, but remains limited due to scarcity of suitable donor organs. This is a particular issue in the pediatric setting, where the smaller child waits disproportionately longer compared with adult patients for size‐matched donor lungs. As ECMO has become more widely accepted, its use as a bridge to lung transplantation in pediatric patients with severe acute lung injury or end‐stage chronic lung disease has been considered. The medical notes from the four pediatric patients were retrospectively reviewed. Our report describes excellent short‐ and medium‐term outcomes in a small number of children who have been bridged to transplant on ECMO.

Continuous arterial blood gas monitoring during bilateral sequential lung transplantation.

OBJECTIVE To determine the accuracy and clinical utility of a continuous arterial blood gas (ABG) monitor during lung transplantation. DESIGN Prospective, observational cohort study. SETTING University hospital. PARTICIPANTS Eleven patients undergoing bilateral sequential lung transplantation (BSLTx). INTERVENTIONS Repeated ABG sampling. MEASUREMENTS AND MAIN RESULTS Agreement was measured by the bias (limits of agreement): pH, 0.006 (-0.10 to 0.10); PaO2, -22 mmHg (-130 to 86 mmHg); and PaCO2, -1.6 mmHg (-13.4 to 10.2 mmHg). Sensitivity and specificity of the Paratrend 7 (Biomedical Sensors, Ltd, Malvern, PA) PaO2 measurements (to detect PaO2 < 100 mmHg) were 84.6% and 97.6%, respectively. CONCLUSION Continuous ABG monitoring with the Paratrend 7 shows sufficiently good agreement with laboratory blood gas analysis during BSLTx and thus is a convenient alternative to intermittent laboratory blood gas measurement. Because of the potential for significant (and sometimes rapid) acid-base disturbances, continuous ABG monitoring may have a role during most lung transplantation procedures.

Massive hyperkalemia during combined heart-lung transplantation: inadvertent contamination with modified Euro-Collins solution

C OMBINED HEART-LUNG transplantation (HLTX) is an accepted form of treatment for selected patients with end-stage cardiopulmonary failure. More than 500 procedures have been performed since its inception in 1981, with some 150 cases performed annually worldwide. Pneumoplegic preservation of the donor lungs and storage during transport involve the use of specialized solutions. At this hospital, 130 transplantation procedures have been performed, 19 of which have been combined HLTXs (13 “domino” donor operations). Modified Euro-Collins solution* (60 mL/kg) has been used as a pneumoplegic solution, preceded by prostacyclin infusion (5 to 20 ng/kg/ min for 5 minutes) into the pulmonary artery.’