Beta-adrenergic blocking drugs in the perioperative period

During the last years increasing evidence has indicated that patients at risk for coronary artery disease may benefit from beta-adrenergic blocking therapy in the perioperative setting. It has been demonstrated that even a relatively brief treatment with beta-adrenergic blocking drugs decreases the incidence of perioperative myocardial ischemia. Even more important is the observation that this reduction in perioperative ischemic events ultimately results in a decrease in long term cardiac morbidity and mortality. Despite overwhelming evidence on the beneficial effects of beta-adrenergic blocking in patients with coronary artery disease, many clinicians still feel some reluctance to use this type of drugs in the perioperative period. We organized a meeting to search for the major objectives that keep anesthetists from implementing prophylactic beta blocking therapy in their daily clinical practice. In this brief review we summarize the results of this meeting and discuss the current knowledge on this subject.

Redo mitral surgery using the Estech endoclamp

BACKGROUND

Redo-CABG surgery remains extremely hazardous in the presence of open bypass grafts. In our patients with mitral valve pathology with open and well-functioning bypass grafts, we explored alternative approaches in order to avoid damage to the grafts by extensive dissection and direct clamping of the ascending aorta. The "Estech procedure," which uses the Estech remote access perfusion (RAP) endoclamp catheter (Estech Inc., Danville, CA), was selected for these patients.

METHODS

From January 1998 to January 2000, 10 patients underwent an Estech procedure for redo mitral surgery. All patients had previous cardiac operations such as coronary artery bypass grafting (CABG) and/or mitral valve procedures. The Estech procedure consisted of an anterior left thoracotomy and peripheral cannulation at femoral site using the Estech endovascular balloon technique. The series was comprised of seven mitral valve replacements, two valve reconstructions, and one closure of a paravalvular leak. One procedure had to be converted to a standard re-sternotomy due to extreme arteriosclerosis of the descending aorta with plaque dislocation at the time of catheter insertion. However, no damage was inflicted to the open bypass grafts.

RESULTS

The follow-up period ranged from six to 30 months and was 100% complete. We encountered one hospital death in our group, which was due to a late post-operative intestinal infarction and multiple organ failure (MOF), and was not procedure related. As expected, morbidity was high in this compromised cohort, but no late death has occurred prior to submission of this article. All survivors progressed to an acceptable NYHA functional class.

CONCLUSION

The excellent results in this complex patient group inspired us to use the Estech procedure as a standard approach for redo mitral surgery.

Outcome in critically ill patients with candidal fungaemia: Candida albicans vs. Candida glabrata

In a retrospective study (1 January 1992-12 December 1998), we investigated population characteristics and outcome in critically ill patients with fungaemia involving C. albicans (n=41) and C. glabrata (n=15). Patients with C. glabrata fungaemia were significantly older compared with patients in the C. albicans group (P=0.024). There were no other differences in population characteristics or severity of illness. Logistic regression analysis showed age (P=0.021), the presence of a polymicrobial blood stream infection (P=0.039), and renal failure (P=0.044) to be independent predictors of mortality. There was no significant difference in in-hospital mortality between the C. glabrata and C. albicans groups (60.0% vs. 41.5%; P=0.24). Since age was an independent predictor of mortality, the trend towards a higher mortality in patients with C. glabrata can be explained by this population being significantly older. In conclusion, we found no difference in mortality between patients with fungaemia involving C. albicans and C. glabrata.

Phosphorylcholine coating of extracorporeal circuits provides natural protection against blood activation by the material surface

OBJECTIVE

The aim of this study is to evaluate the use of a new coating, mimicking the outer cell membrane, in paediatric cardiac surgery.

METHODS

Two groups of ten patients with a body weight below 8 kg, undergoing elective cardiac operations for different congenital anomalies, were prospectively enrolled in this study. In one group the whole extracorporeal circuit, including the cannulas, was coated with phosphorylcholine (PC). In the second group the same circuit was used without coating. Platelet activation (thromboxane B2 (TXB2), beta-thromboglobulin (betaTG)), activation of the coagulation system (F1+2), leukocyte activation (CD11b/CD18) and terminal complement activation (TCC) were analyzed pre-cardiopulmonary bypass (CPB), at 15, 60 min of CPB, at the end of CPB, 20 min post CPB and at postoperative day 1 and 6.

RESULTS

No statistical differences were found for F1+2 and CD11b/CD18. After onset of CPB mean levels of TCC remained stable in the PC group whereas an increase was observed in the control group. During CPB betaTG values in both groups increased to a maximum at the end of CPB. Within groups the increase in betaTG levels during CPB was statistically significant (P<0.05) from baseline in the control group starting from 60 min of CPB whereas no statistical difference was observed in the PC group. After the start of CPB TXB2 mean levels increased to 405+/-249 pg/ml in the PC group vs. 535+/-224 pg/ml in the control group. After this initial increase there was a small decline in the PC group with further increase. This was in contrast to the control group were TXB2 levels further increased up to a mean of 718+/-333 pg/ml at the end of CPB (P=0.016).

CONCLUSIONS

Phosphorylcholine coating had a favourable effect on blood platelets, which is most obvious after studying the changes during cardiopulmonary bypass. A steady increase of TXB2 and betaTG was observed in the control group, whereas plateau formation was observed in the phosphorylcholine group. Clinically, this effect may contribute to reduced blood loss and less thromboembolic complications. Complement activation is lower in the coated group.

The influence of sufentanil and/or clonidine on the duration of analgesia after a caudal block for hypospadias repair surgery in children

The aim of this study was to evaluate whether the addition of clonidine, or sufentanil, or both, to a bupivacaine solution for a caudal block prolonged the period of analgesia after operation in children. Sixty ASA class I or II boys, aged between 8 months and 13 years, admitted for hypospadias repair were enrolled into a prospective randomised study. After induction of general anaesthesia and endotracheal intubation the children were allocated into four groups. Group I received 0.5 mL kg(-1) bupivacaine 0.25% caudally, in addition group II received 1 microg kg(-1) clonidine, group III 0.5 microg kg(-1) sufentanil and group IV 0.5 microg kg(-1) clonidine and 0.25 microg kg(-1) sufentanil. The concentrations of clonidine and sufentanil in group IV were halved to reduce possible side-effects with higher dosages. Analgesia and side-effects were assessed 2, 4, 6, 8 and 12 h after operation. No significant differences were found among the four groups for the pain scores at 2, 4, 6, 8 and 12 h. All groups had a similar frequency of vomiting and a comparable appetite and quality of night rest during the first 24 h following the operation. There was no significant difference in the requirement for additional doses of analgesics. The addition of sufentanil, or clonidine, or both, to bupivacaine for caudal administration provides no additional clinical benefit over bupivacaine alone.

A comparison of transoesophageal echocardiographic Doppler across the aortic valve and the thermodilution technique for estimating cardiac output

This study was undertaken in order to elucidate the differences between various planes of measurement and Doppler techniques (pulsed- vs. continuous-wave Doppler) across the aortic valve to estimate cardiac output. In 45 coronary artery bypass patients, cardiac output was measured each time using four different Doppler techniques (transverse and longitudinal plane, pulsed- and continuous-wave Doppler) and compared with the thermodilution technique. Measurements were performed after induction of anaesthesia and shortly after arrival in the intensive care unit. Optimal imaging was obtained in 91% of the patients, in whom a total of 82 measurements of cardiac output were performed. The respective mean (SD) areas of the aortic valve were 3.77 (0.71) cm2 in the transverse plane and 3.86 (0.89) cm2 in the longitudinal plane. A correlation of 0.87 was found between pulsed-wave Doppler cardiac output and the thermodilution technique in either transverse or longitudinal plane. Correlation coefficients of 0.82 and 0.84 were found between thermodilution cardiac output and transverse and longitudinal continuous-wave Doppler cardiac output, respectively. Although thermodilution cardiac output is a widely accepted clinical standard, transoesophageal Doppler echocardiography across the aortic valve offers adequate estimations of cardiac output. In particular, pulsed-wave Doppler cardiac output in both the transverse and longitudinal plane provides useful data.

Management of candidal thrombophlebitis of the central veins: case report and review

Candidemia and major organ candidiasis are problems that emerged in the past 2 decades and that are partially due to medical progress. Catheter-related thrombosis of the central veins is known to be a frequent but mostly subclinical complication of central venous lines. Although candidemia and catheter-related thrombosis are frequent, candida thrombophlebitis of the central veins is rarely reported. We recently successfully treated a 19-year-old polytrauma patient with candidal thrombophlebitis of the innominate vein. Despite catheter removal and therapy with amphotericin B, recurrent candidemia and signs of infection persisted, and a complete resection of the involved vein had to be performed. Only 16 well-documented cases of candidal thrombophlebitis of the central veins in adults have been reported over the past 20 years. An analysis of these 16 patients, together with our patient, is made in relation to risk factors, clinical features, diagnosis, therapy, and mortality.

Transoesophageal echocardiography in the critically ill

Echocardiography offers real-time bedside diagnosis and monitoring of a variety of structural and functional abnormalities of the heart. Transoesophageal echocardiography, in particular, provides information on cardiac contractility, filling status and output, valvular morphology and function and on the structure of the ascending and descending aorta in the critically ill patient. The full range of modalities of echocardiography, including M-mode, 2-D-mode, colour Doppler and spectral Doppler, is at the disposal of the intensive care specialist. In this review, the indications for and the clinical impact of transoesophageal echocardiography and Doppler are discussed.

[Transesophageal echocardiography in anesthesia and intensive care. The diagnostic importance of transesophageal echocardiography]

Transoesophageal echocardiography (TEE) is recognised as a semi-invasive technique that has an increasing impact as a diagnostic tool in anaesthesia and intensive care medicine. However, adequate assessment of TEE is based on knowledge of basic echocardiographic principles and their limitations and sufficient educational training of the user. TEE has an established role in various clinical circumstances. It often saves time-consuming investigations for the diagnosis of aortic injuries in trauma patients. It is also useful in patients undergoing cardiac valve repair or congenital heart surgery with regard to assessment of the operative success. In patients with severe hypotension TEE may identify the cause, and thereby facilitate successful patient management. Moreover, TEE has an impact on the diagnosis of endocarditis and pathologic findings within the heart and pericardial sac. TEE-associated diagnosis and decision-making may lead to an improved clinical outcome, which in turn may lead to subsequent cost reduction.

Left ventricular systolic and diastolic function in septic shock

OBJECTIVE

The identification of myocardial dysfunction in septic shock has not yet been fully elucidated. We therefore studied patients with persistently vasopressor-dependent septic shock, both with invasive haemodynamic monitoring and transoesophageal two-dimensional and Doppler echocardiography (TEE).

DESIGN

Prospective study.

SETTING

General ICU in University Hospital.

PATIENTS AND METHODS

All patients were monitored with arterial and pulmonary artery catheters. Haemodynamics were obtained concomitantly with TEE measurements. TEE was performed at three levels: a) a midpapillary short axis view of the left ventricle (LV) in order to measure end-systolic and end-diastolic areas; b) at the level of both the mitral valve for early (E) and late (A) filling parameters and c) the level of the right upper pulmonary vein for systolic (S) and diastolic (D) filling characteristics. Each parameter was characterised by maximal flow velocity and time velocity integral.

RESULTS

Although the measurements of cardiac index demonstrated a wide range, three subsets of patients were identified post hoc after analysis on the basis of different Doppler patterns: first, patients with a LV without regional wall motion abnormalities and both E/A and S/D greater than 1 (group 1); second, patients with a comparable haemodynamic condition, apparently normal LV systolic function but with altered Doppler patterns: S/D less than 1 in conjunction with E/A more than 1 (group 2); finally, patients with compromised global LV systolic function, E/A less than 1 and S/D less than (group 3).

CONCLUSIONS

Notwithstanding the known various interfering factors which limit the broad applicability of TEE to determine LV function in septic shock, our data suggest that cardiac dysfunction in septic shock shows a continuum from isolated diastolic dysfunction to both diastolic and systolic ventricular failure. These data strengthen the need of including the evaluation of pulmonary venous Doppler parameters in each investigation in order to obtain supplementary information to interpret diastolic function of the LV in septic shock patients.

Limited intentional normovolemic hemodilution: ST-segment changes and use of homologous blood products in patients with left main coronary artery stenosis

OBJECTIVE

To assess and compare the effects of limited intentional normovolemic hemodilution (LINH) on ST-segment changes and to evaluate the need for homologous blood products.

DESIGN

Prospective, randomized study.

SETTING

University hospital.

PARTICIPANTS

Seventy-one patients with left main stenosis scheduled for semi-urgent coronary artery bypass grafting.

INTERVENTIONS

Patients in group A (n = 39) underwent LINH during the prebypass period until a hematocrit of 34% was obtained. Simultaneously, succinyl-linked gelatin was infused. In group B (n = 32), no hemodilution was performed. Mean arterial pressure and central venous pressure were kept as constant as possible. During the postbypass period, autologous blood was retransfused. The need for homologous blood products was noted intraoperatively and postoperatively.

MEASUREMENTS AND MAIN RESULTS

ST-segment analysis of lead II and chest lead was continuously performed in all patients. An ST-segment change was defined as a decrease from baseline of 1.0 mm (-0.1 mV). The appearance and degree of ST-segment depression were comparable in both groups (group A: 7 patients -0.1 mV, 1 patient -0.2 mV; group B: 5 patients -0.1 mV; 3 patients -0.2 mV). In group A, ST-segment depression occurred during and after the blood exchange. However, the mean duration of the ST-segment depression (group A: 33 +/- 18 minutes; group B: 20 +/- 10 minutes) was comparable between groups. In group A, a mean of 750 mL +/- 245 mL of blood was obtained. Total blood loss was significantly higher in group B (p < 0.052); 25 patients in group A (64%) and 12 patients in group B (38%) did not require homologous blood products (p < 0.03). Intraoperatively, only the need for packed red cells was greater in group B (p < 0.04). Postoperatively, the use of homologous blood products is higher than intraoperatively (p < 0.02).

CONCLUSIONS

LINH performed in patients with left main stenosis, scheduled for semi-urgent coronary bypass, is not associated with increases in frequency, degree, or duration of ST-segment changes. This procedure allowed a reduction in the number of patients who received homologous blood products.

Low extracorporeal priming volumes for infants: a benefit?

An extracorporeal circuit consisting of an oxygenator especially designed for neonatal use and appropriately sized tubing, with an average total priming volume of 205 ml, was used on 80 infants undergoing cardiac surgery for congenital heart-disease. The priming volume and foreign surface area of the circuit were determined. The influence of low priming volumes on the use of blood products and the management of cardiopulmonary bypass was studied. No whole blood or platelets were used in this study. The mean volume of packed red blood cells used over the hospital stay was 202 +/- 67 ml. The mean volume of fresh frozen plasma (FFP) used until the second postoperative day was 62 +/- 72 ml. The mean total blood loss until the second postoperative day was 15.8 +/- 9.2 ml/kg. The priming volume of the extracorporeal circuit was 62% lower than values commonly reported in the literature. The low priming volume had a strong influence on the use of platelets and FFP and to a lesser extent on the use of packed red blood cells.

Transoesophageal echocardiographic evaluation of ventricular function during transvenous defibrillator implantation

BACKGROUND

Intraoperative testing and defibrillation threshold determination may jeopardise patients, scheduled for implantation of a cardioverter-defibrillator (ICD). The purpose of this study was the assessment of the influence of consecutive defibrillation attempts on left ventricular systolic and diastolic function by means of transoesophageal echocardiography (TEE).

METHODS

Eighteen patients with malignant ventricular arrhythmias that were resistant to antiarrhythmic drugs were monitored with TEE before, during and after implantation of a cardioverter-defibrillator. Left ventricular fractional area contraction as a measure of ejection fraction was assessed before and after each defibrillation attempt. Transmitral and right upper pulmonary venous flow parameters were evaluated before and after the whole implantation procedure.

RESULTS

Adequate data were available in 14 patients during 4 consecutive attempts. No major alterations were observed in heart rate or fractional area contraction, measured at 30 s and 3 min after defibrillation. Overall, the ratio of early-to-late transmitral filling decreased significantly after the implantation procedure (from 0.91 +/- 0.12 to 0.82 +/- 0.14; P < 0.05). Systolic pulmonary venous flow velocity decreased from 0.49 +/- 0.11 to 0.41 +/- 0.10 m/s (P = 0.04); this decrease was observed in both groups. A significant increase of the atrial contraction wave (from 0.25 +/- 0.06 to 0.34 +/- 0.07 m/s; P < 0.03) was seen. Subdividing patients related to their precperative ejection fraction, a significant decrease of the early-to-late transmitral filling of the LV was revealed in patients with ejection fraction less than 35% (group 1). Also, a significantly lower systolic fraction of the pulmonary venous flow after ICD implantation in conjunction with a significantly longer diastolic flow time was shown in this patient group in comparison with patients with a preoperative ejection fraction of more than 35% (group 2).

CONCLUSION

Defibrillation threshold testing of the ICD system changes LV inflow characteristics and impedes diastolic function of the left ventricle and may thus precipitate heart failure by this mechanism. No deleterious effects of threshold testing were observed with respect to fractional area contraction nor any deterioration of LV function was found in a clinically significant amount due to consecutive defibrillation attempts.

Rapidly progressive pulmonary artery hypertension and end-stage liver disease

Pulmonary hypertension is a recognized but unusual complication of liver disease. It can complicate the perioperative course of liver transplantation. Mild to moderate pulmonary hypertension is generally well tolerated during the procedure and does not appear to contribute to mortality. Since the pulmonary vascular disease may progress rapidly, it may have advanced to the point of irreversibility at the time of surgery. So, patients with known moderate pulmonary hypertension should have pulmonary arterial catheterisation immediately prior to transplantation. If pulmonary artery hypertension has become severe, then a preoperative trial of vasodilators is warranted. If this fails, the procedure should be cancelled. We present a patient with alcoholic liver cirrhosis in whom a rapidly progressive pulmonary hypertension made liver transplantation impossible.

Awareness during anaesthesia for implantable cardioverter defibrillator implantation. Recall of defibrillation shocks

Implantable cardioverter defibrillator implantation is performed under general anaesthesia. This report describes awareness or recall in two of 33 patients scheduled for implantation. After induction, anaesthesia was maintained using continuous infusions of propofol and atracurium and intermittent boluses of alfentanil. Propofol was given in the same arm as the implantation side. In these two patients propofol flowed out of the bleeding central venous access. To minimise the possibility of awareness, we advise that continuous infusions should be administered intravenously on the contralateral side to the implantation and that neuromuscular blocking agent be given by intermittent bolus injections.