Re: Effect of intrapartum epidural analgesia on rate of emergency delivery for presumed fetal compromise: nationwide registry-based cohort study

Linked article: This Correspondence comments on Damhuis et al. Click here to view the article.

Cardiac Stress in High-Risk Patients Undergoing Major Endovascular Surgery-Focus on Diastolic Function

OBJECTIVES

The purpose of this study was to determine the relationship between the changes in diastolic function and their association with cardiac biomarkers in the perioperative period in patients undergoing complex endovascular aortic repair.

DESIGN

Prospective observational study.

SETTING

Single-center academic hospital, central teaching hospital in Warsaw, Poland.

PARTICIPANTS

The study comprised 27 high-risk patients scheduled for elective endovascular repair of aortic aneurysm.

INTERVENTIONS

Complex endovascular procedure using branched endograft of the thoracoabdominal aorta. Branches of the stent grafts included renal arteries, the superior mesenteric artery, and the celiac trunk.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was to evaluate changes in diastolic function parameters assessed with transthoracic echocardiography at two and 24 hours postoperatively. The major secondary outcomes were changes in N-terminal pro-B-type natriuretic peptide (NT-proBNP) and troponin I concentrations, systolic function parameters, hemodynamic parameters at two and 24 hours, length of hospital stay, and 30-day mortality. There was a reduction in e' wave velocity on both the septal and lateral sides at two hours compared with the baseline (p = 0.041 and p = 0.05, respectively). There was an increase in both NT-proBNP and troponin I concentrations after surgery (p = 0.002 and p = 0.034, respectively), with troponin I peaking two hours after surgery and NT-proBNP peaking 24 hours after surgery.

CONCLUSIONS

Patients undergoing a branched endovascular aortic repair of a thoracoabdominal aortic aneurysm experience a cardiac insult that manifests with deterioration in diastolic parameters and concomitant increases of troponin and NT-proBNP concentrations. Additional large-scale prospective studies are required to confirm this phenomenon.

Quantification of piritramide in human colostrum

WHAT IS KNOWN AND OBJECTIVE

In our university hospital (UZBrussel), one of the options to control post-operative pain after a Caesarean section under general anaesthesia is to administer piritramide by patient-controlled intravenous analgesia (PCIA). As no information is available about the possible transfer of this synthetic narcotic analgesic into breastmilk, women are frequently advised not to breastfeed their newborn. A sensitive liquid chromatographic (LC) method coupled with UV detection will therefore be developed and validated for the quantification of piritramide in colostrum samples to evaluate the presence of the analgesic in the first milk.

METHODS

The method included the isolation and concentration of piritramide from colostrum using protein precipitation and solid-phase extraction (SPE) using a mixed-mode cation exchange sorbent. Subsequently, the extracted samples were analysed on a microbore C₁₈ column (1 mm id) and a mobile phase consisting of 15 mm ammonium hydroxide in methanol/tetrahydrofuran/water 50 : 10 : 40 V/V/V.

RESULTS AND DISCUSSION

As colostrum contains a high amount of proteins, mixed-mode cation exchange SPE was preceded by a 1 : 2 dilution and protein precipitation with phosphoric acid followed by double centrifugation of the samples. The reversed-phase LC-UV method used a mobile phase at alkaline pH to obtain a selective method for piritramide and the internal standard pipamperone. After investigating the validation characteristics (linearity, accuracy, precision and stability), samples from ten patients who had received piritramide via PCIA during the first 48 h post-partum were analysed.

WHAT IS NEW AND CONCLUSION

To the best of our knowledge, this is the first method described for the quantification of the synthetic narcotic analgesic piritramide in colostrum samples. The obtained results suggest that after the administration of this opioid by PCIA to nursing mothers low concentrations of piritramide can be found in the first milk, but are mostly below the limit of quantification of 30 ng/mL.

Usability of dexmedetomidine for deep sedation in infants and small children with respiratory morbidities

BACKGROUND

Children with respiratory morbidities are at increased risk of developing adverse respiratory events while undergoing deep sedation. Dexmedetomidine possesses sedative properties with minimal respiratory depression. This report aimed to determine the usability of dexmedetomidine in children with significant respiratory morbidities who require deep sedation.

METHODS

Medical records of children with ASA classification III who had at least three characteristics of respiratory morbidities and who received dexmedetomidine sedation for magnetic resonance imaging (MRI) between January 2014 and May 2015 were retrospectively reviewed. Dexmedetomidine was administered as a bolus of 1 μg/kg over 10 min followed by 1 μg/kg/h infusion. If necessary, an additional bolus dose was given and the infusion rate was increased to 2 μg/kg/h. Respiratory morbidities, haemodynamic parameters, total dexmedetomidine dose, adverse cardiorespiratory events and sedation characteristics were analysed.

RESULTS

Nineteen out of 642 children who underwent MRI were eligible for evaluation. Seventeen children (89%) had at least four characteristics of respiratory morbidities. The median [IQR] age was 9 months [3.5-14]. All patients completed MRI scans while breathing spontaneously via the native airway. No episodes of adverse respiratory events or haemodynamic instability were observed. Children who were administered a lower dexmedetomidine dose and had a shorter sedation time were more likely to be younger than 1 year of age.

CONCLUSION

These data demonstrate that dexmedetomidine deep sedation was well-tolerated in children with significant respiratory morbidities. Moreover, children younger than 1 year of age were administered lower dexmedetomidine dose than children older than 1 year of age for the same sedation level.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT02555605.

Randomised controlled trial of spinal anaesthesia with bupivacaine or 2-chloroprocaine during caesarean section

BACKGROUND

Neuraxial anaesthesia is the desired method for Caesarean section. Bupivacaine is a well-known local anaesthetic. It has a long duration of action and can cause unpredictable levels of anaesthesia with subsequent prolonged discharge time. 2-Chloroprocaine has a rapid onset of action, producing an excellent sensory and motor block and has a rapid hydrolysis in the bloodstream by pseudocholinesterase. We compared bupivacaine and 2-chloroprocaine for spinal anaesthesia during Caesarean section. The primary endpoint was the earliest reversal sign of the motor block.

METHODS

Sixty ASAI/II patients, planned for elective singleton Caesarean section, were equally randomised to three groups. All patients received a combined spinal-epidural anaesthesia. The first group received 2-chloroprocaine (40 mg) without sufentanil, the second group received 2-chloroprocaine (40 mg) with sufentanil (1 μg) and the third group received hyperbaric bupivacaine (7.5 mg) with sufentanil (1 μg) as a spinal anaesthetic. Motor and sensory blockade were assessed at specific time points.

RESULTS

There was no difference between the three groups regarding the time to regression of the motor block. However, at 5 min post spinal injection, the level of sensory block was higher for both groups with 2-chloroprocaine, in comparison with the bupivacaine group.

CONCLUSION

2-Chloroprocaine can be used for low risk Caesarean section in healthy parturients. There is no difference in time to motor block resolution compared to bupivacaine. Motor recovery seems more predictable for 2-chloroprocaine and may be beneficial for the breastfeeding initiation.

Fighting human error : what surgeons can learn from aviators

BACKGROUND

The rigorous implementation of safety policies have made air travel one of the safest modes of transport. Health institutions and hospital managing bodies increasingly adopt cues from aviation safety protocols and policies in an attempt to reduce medical errors and patient harm. Among hospital staff, surgeons are most likely to be confronted with these aviation-derived safety concepts.

METHODS

This article aims to familiarize surgeons with the concepts and methodology of safety policies in modern aviation safety, many of which have been applied in the setting of surgery, or have potential to do so. We review the use of checklists, crew resource management, the sterile cockpit, blame free reporting and human fatigue. We discuss how these concepts can be translated to the operating room and illustrate their relevance through a comparative description of historical air accidents and surgical incidents from our own clinical experience. We also indicate relevant differences and similarities between flight crews and surgical teams and their respective infrastructures, as these may impede or facilitate the adoption of aviation safety policies. Finally, we offer some recommendations to effectively implement aviation safety policies in the operating room.

Importance of preoperative anaesthetic consultation in perioperative medicine

This report describes two patients for whom the preoperative, anaesthetic consultation led to postponing planned surgery because of important, undiagnosed health problems. In one of the two cases, this consultation was even life-saving. However, actual literature cannot prove any advantage on the outcome of the individual patient. The only proven advantages in favour of pre-operative consultation are a reduced length of stay in the hospital and a reduction in the cost of preoperative testing.

Sepsis and septic shock: pathophysiological and cardiovascular background as basis for therapy

INTRODUCTION

Sepsis and septic shock are common causes for admission to intensive care units. The morbidity and mortality remain unacceptably high despite the advanced treatments.

OBJECTIVES

To review the most commonly reported underlying mechanisms of sepsis and septic shock, besides discussion of sepsis-induced cardiovascular dysfunction. Therapeutic strategies for sepsis-induced myocardial depression are briefly discussed.

DATA SYNTHESIS

The development of sepsis and septic shock is multifactorial. Two major mechanisms contribute to the haemodynamic collapse. The extrinsic and intrinsic mechanisms induce a complex cascade which results in the release of pro- and anti-inflammatory mediators. Sepsis develops when the initial, appropriate host response to an infection becomes amplified and then dysregulated leading to haemodynamic and circulatory changes. The pro-inflammatory mediators tumour necrosis factor alpha, interleukin-beta and nitric oxide play a significant role in sepsis-related hypotension, shock and depression of cardiomyocyte contractility. Septic cardiac dysfunction can be explained by various mechanisms: changes in circulating volume, down-regulation of beta-adrenergic receptors, depressed post-receptor signalling pathways, reduced calcium release from the sarcoplasmic reticulum and impaired electromechanical coupling and reduced calcium sensibility at the myofibrillar level. Mitochondrial derangement seems to be of great importance in tissue injury and sepsis-associated multi organ failure. There is no consistent protocol for treating sepsis and septic shock. Guidelines include early goal-directed therapy, source control and haemodynamic supportive measures.

CONCLUSION

Further studies are needed to distinguish the importance of these various mechanisms. We recommend that further investigational work should focus on the recovery of the mitochondria-related bio-energetic shut down as the mitochondria could play a key role in the understanding of apoptosis and protective measures. Understanding the pathophysiology of sepsis and septic shock will inevitably lead to a more accurate treatment of these still too often fatal syndromes.

Doppler echocardiography as a modern tool to diagnose and monitor non-cardiac surgical patients: does it improve outcome?

Echocardiography and Doppler provide intraoperative and immediate insight when a haemodynamic deterioration occurs. Both morphological and haemodynamic features can be diagnosed instantly. Furthermore, this tool is used as a functional haemodynamic monitoring device offering on line information on systolic function, preload and afterload. No clear data exist on improvement of outcome in noncardiac surgery, but analogy to cardiac patients suggest strongly outcome can be advanced with echo-Doppler.

„Statistische Prozesskontrolle“ als Monitoring-Tool zur Evaluierung von Reorganisationsmaßnahmen

INTRODUCTION

The German health care system is currently in a constant state of flux owing to enhanced competition and to the increasing focus on economic aspects. Medical services, especially treatment processes, are being reorganised in an attempt to adapt them to the new economic challenges. Ideally, radical reorganisation and streamlining of medical therapy processes should be accompanied by controlling and quality management systems. The purpose of this is to monitor the intensity of any economic and any patient-related (side)-effects. Business management techniques are needed that allow online and long-term performance reviews of reorganisation measures once initiated.

METHODS

In industry, the method applied for this purpose is statistical process control (SPC). The present study demonstrates for the first time that use of this monitoring tool can be extended to the medical sector. In an intensive care unit (ICU) the following process parameters were monitored: duration of sedation, time to persisting spontaneous breathing, length of stay in ICU, length of stay in hospital, patient mortality in ICU and in the next 30 days after admission to the ICU. Group 1 was made up of 87 patients examined before and group 2, 93 patients after process optimisation. The main feature of the reorganisation was application of a new analgo-sedation technique and of the weaning concept.

RESULTS

In group 2 duration of sedation, time to spontaneous breathing and length of stay on the ICU were significantly shorter than in group 1. The length of stay in hospital, patient mortality in the ICU and 30 days after the initiation of intensive care did not differ significantly between the two groups.

CONCLUSION

Economic and patient-related key figures can be evaluated with SPC. It allows online assessment both before and during process optimisation, and especially in the long term afterprocess optimisation.

Beat-to-beat change in "myocardial performance index" related to load

BACKGROUND

This study was designed to assess the relationship of the "myocardial performance index" (MPI) to the beat-by-beat change in pre-load with static or unchanged contractile status.

METHODS

Eight anesthetized juvenile pigs were studied using direct measurement of the left ventricular pressure and volume. Transient inflation of a vena cava balloon catheter produced controlled pre-load alterations. Consecutive beats were analyzed, grouped for first, second, third, etc. during the pre-load alteration, and evaluated for the change in MPI during the same contractile status with a controlled pre-load alteration. Two pharmacologic inotropic interventions were also included to generate several myocardial conditions in each animal.

RESULTS

MPI demonstrated a strong linear relationship to the pre-load and after-load. MPI increased progressively during decreasing end-diastolic volume, mostly related to changes in ejection time. MPI was observed at the same level for three different myocardial function conditions (all eight animals), with a different relationship between MPI and pre-load noted for each observation.

CONCLUSIONS

MPI is strongly load dependent, and can vary widely in value for the same contractile status if the load is varied. The use of this index in critically ill patients should be limited in this respect. Further work is needed to establish the relationship of MPI to load and contractile status.

A comparative study of preload-adjusted maximal and peak power: assessment of ventricular performance in clinical practice

This study was performed to determine whether preload-adjusted peak power can act as a surrogate for preload-adjusted maximal power in the assessment of left ventricular performance in the clinical setting. Ninety-nine consecutive patients who had undergone elective coronary artery bypass grafting were studied. Fifty-five of these patients were divided into four study groups. Afterload was changed with phenylephrine (n = 12) or glyceryl trinitrate (n = 13), preload was increased with intravenous colloid (n = 18), and contractility was increased with dobutamine (n = 12). There was excellent correlation between the two indices (r = 0.99, y = 1.0168x + 0.0769; p < 0.0001). Manipulation of neither preload nor afterload affected the indices. Both indices increased significantly during dobutamine infusion (p = 0.002). In conclusion, preload-adjusted peak power can be used as a substitute for preload-adjusted maximal power in the determination of ventricular performance in clinical practice.

Estimation of myocardial performance in CABG patients

Myocardial performance index (MPI) permits a relative easy estimation of global left ventricular (LV) systolic and diastolic function. It was shown that MPI inversely correlated strongly with the maximum derivative of LV pressure with respect to time (+dP/dtmax). The current study evaluated the change of MPI during and immediately after coronary artery bypass surgery (CABG) surgery and analyzed the relationship between MPI and hydraulic energy (exemplified by preload adjusted maximal power-PAMP) during that same period. The study was conducted in 45 patients undergoing CABG. After induction of anaesthesia, 10 min after revascularization and 2 h postoperatively, haemodynamics were assessed. Preload was characterized by LV end-diastolic area indexed for BSA (LVEDAI); afterload was estimated by arterial elastance (Ea) and indexed systemic vascular resistance (SVRI). Global myocardial performance was indicated in terms of MPI and contractility was achieved by PAMP. Myocardial performance index increased postoperatively (0.44 +/- 0.13, 0.37 +/- 0.17 and 0.50 +/- 0.16, respectively; P < 0.001). Preload adjusted maximal power did not alter significantly (1.90 +/- 1.24, 2.02 +/- 1.34 and 2.12 +/- 1.00 W cm(-2)*10(4), respectively). Left ventricular enddiastolic area indexed did not change. Arterial elastance augmented to 0.76 +/- 0.39, 0.80 +/- 0.40 and 1.01 +/- 0.43 mmHg ml(-1), respectively; P < 0.001. Systemic vascular resistance did not change. A relationship was found between 1-MPI/LVEDAI2 and PAMP (R2 = 0.50). This study shows that in the setting of CABG surgery, MPI appears to be a good measure of global LV function.

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.

Post-traumatic transverse dissection of the caudal thoracic aorta diagnosed by transoesophageal echocardiography

Transverse dissection of the distal aorta is a rather rare complication of spinal trauma. Transoesophageal echocardiography (TEE) appears to have a supplementary value in diagnosing post-traumatic transverse dissection of the caudal thoracic aorta. We present a case where the advantages and additional value of TEE are particularly apparent.