Recommendations for transoesophageal echocardiography: update 2010.

Transoesophageal echocardiography (TOE) is a standard and indispensable technique in clinical practice. The present recommendations represent an update and extension of the recommendations published in 2001 by the Working Group on Echocardiography of the European Society of Cardiology. New developments covered include technical advances such as 3D transoesophageal echo as well as developing applications such as transoesophageal echo in aortic valve repair and in valvular interventions, as well as a full section on perioperative TOE.

Decline in research publications from the United Kingdom in anaesthesia journals from 1997 to 2006.

We undertook this survey to identify the trend in the published output of original research in anaesthesia emanating from the United Kingdom (UK) in a 10-year period from 1997 to 2006, inclusive. We examined seven major anaesthetic journals for each of the 10 years, and four other specialist journals for the years 1997, 2000, 2003 and 2006. We included papers on experimental research, randomised controlled clinical trials, large observational studies and case series, formal equipment and apparatus assessments, but we excluded editorials, comments, reviews including systematic reviews, special articles, small case series and case reports, questionnaire surveys of clinical practice and correspondence. We found a highly significant reduction in published research output from the UK in the period under study (% change per year; -5.7 (95% CI -7.4 to -4.0), a trend which was significantly different (p < 0.001) from the trend of changes in research publications worldwide (-1.0% change per year; 95% CI -1.7 to 0.0). We discuss the implications of these findings for UK anaesthesia research strategy.

Recombinant human antithrombin III restores heparin responsiveness and decreases activation of coagulation in heparin-resistant patients during cardiopulmonary bypass.

OBJECTIVES: We sought to evaluate the efficacy of recombinant human antithrombin III for restoration of heparin responsiveness in heparin-resistant patients scheduled for cardiac surgery. METHODS: This was a multicenter, randomized, double-blind, placebo-controlled study in heparin-resistant patients undergoing elective cardiac surgery. Patients were considered heparin resistant if the activated clotting time was less than 480 seconds after 400 U/kg heparin. Fifty-two heparin-resistant patients were randomized into 2 cohorts. One cohort received a single bolus (75 U/kg) of recombinant human antithrombin III (n = 28), and the other, the placebo group (n = 24), received a normal saline bolus. If the activated clotting time remained less than 480 seconds, this was defined as treatment failure, and 2 units of fresh frozen plasma were transfused. Patients were monitored for adverse events during hospitalization. RESULTS: Six (21%) of the patients in the recombinant human antithrombin III group received fresh frozen plasma transfusions compared with 22 (92%) of the placebo-treated patients ( P < .001). Two units of fresh frozen plasma did not restore heparin responsiveness. There was no increased incidence of adverse events associated with recombinant human antithrombin III administration. Postoperative 24-hour chest tube bleeding was not different in the 2 groups. Surrogate measures of hemostatic activation suggested that there was less activation of the hemostatic system during cardiopulmonary bypass in the recombinant human antithrombin III group. CONCLUSION: Treatment with recombinant human antithrombin III in a dose of 75 U/kg is effective in restoring heparin responsiveness and promoting therapeutic anticoagulation for cardiopulmonary bypass in the majority of heparin-resistant patients. Two units of fresh frozen plasma were insufficient to restore heparin responsiveness. There was no apparent increase in bleeding associated with recombinant human antithrombin III.

Use of isradipine in hypertension following coronary artery bypass surgery.

A dose-finding pilot study including six patients concluded that isradipine at an initial rate of 0.6 microgram/kg/minute, decreasing to 0.3 microgram/kg/minute with further adjustments as necessary, was safe for the treatment of post-aortocoronary bypass graft hypertension. A comparative study followed, comprising 20 patients randomly assigned to receive isradipine (starting at 0.6 microgram/kg/minute) or nitroprusside (initially 1 microgram/kg/minute) for the treatment of post-aortocoronary bypass graft hypertension. Both drugs produced a satisfactory reduction in arterial blood pressure accompanied by a decrease in systemic vascular resistance. Central venous pressure and mean pulmonary artery pressure decreased with nitroprusside, but both increased with isradipine. Pulmonary capillary wedge pressure was reduced, heart rate increased, and cardiac output was minimally changed with nitroprusside. However, wedge pressure was maintained with isradipine and there was no tachycardia. An increase in cardiac output was seen, associated with an increase in stroke index. Isradipine is a more specific treatment for post-aortocoronary bypass graft hypertension than nitroprusside because its systemic arterial dilating effect is associated with a minimum of other circulatory changes.

Time-course of free radical activity during coronary artery operations with cardiopulmonary bypass.

Myocardial and pulmonary impairment after cardiopulmonary bypass may be caused by oxygen free radicals produced by reperfusion and by activated neutrophils. Free radical activity was assessed by assays for lipid peroxidation (thiobarbituric acid-reactive material) and phospholipid-esterified diene conjugation (18:2[9,11]/18:2[9,12] molar ratio) in 25 patients during coronary artery operations. Arterial blood samples were obtained before, during the ischemic period, and for 24 hours thereafter. There were no significant changes in free radical indices during the ischemic periods, but after cessation of bypass they increased significantly. Ten minutes after bypass thiobarbituric acid-reactive material rose from 96 (median; range 65 to 145) nmol/gm albumin to 138 (85 to 200) nmol/gm albumin (p < 0.001), and molar ratio rose from 2.23% (0.45% to 7.70%) to 2.51% (0.39% to 7.93%) (p < 0.02). Values of thiobarbituric acid-reactive material subsequently decreased, but molar ratio reached a peak at 4 hours after bypass, 2.64% (0.55% to 10.08%) (p < 0.001), thereafter returning to baseline. The postoperative increases in thiobarbituric acid-reactive material and in molar ratio were correlated (r = +0.53; p = 0.006). These increases in thiobarbituric acid-reactive material and in molar ratio were not related to age, preoperative left ventricular function, or the number of grafts performed. Increase in thiobarbituric acid-reactive material correlated with the duration of cardiopulmonary bypass (r = +0.43; p = 0.03). In 10 patients in whom cardiopulmonary bypass was performed using a bubble oxygenator, the increases in thiobarbituric acid-reactive material were significantly greater than in the 15 in whom a membrane oxygenator was used (p < 0.02). These data show that after apparently uncomplicated coronary operations with bypass there is an increase in lipid peroxidation and diene conjugation, indicating increased free radical activity. This increase varies between patients and does not relate to patient or surgical factors but may depend on the type of oxygenator employed during bypass.

Nasal intermittent positive-pressure ventilation in weaning intubated patients with chronic respiratory disease from assisted intermittent, positive-pressure ventilation.

Nasal intermittent positive-pressure ventilation (NIPPV) has been used for domiciliary ventilatory support, and to avoid intubation for acute respiratory failure in patients with chronic airflow limitation (CAL). Its role in weaning patients from assisted ventilation in intensive care has not been defined. We have used NIPPV to wean 14 patients with respiratory disease who were referred either because of predicted difficulty in weaning or failure to wean using standard techniques. Twelve patients were ventilated for acute respiratory failure; eight patients had CAL and four had chest wall or neuromuscular disease. Two further patients with chest disease were difficult to wean following surgery. Weaning was successful in 13 patients. NIPPV corrected hypoxia, reduced hypercapnia and was well tolerated. Weaning from NIPPV was achieved in all patients with CAL, although three patients with chest wall disease later required domiciliary ventilatory support. All but one of the patients survived to leave hospital. NIPPV may have an important role in weaning from assisted ventilation, particularly in patients with underlying chronic respiratory disease. This preliminary report needs to be followed by a controlled study comparing NIPPV with established weaning methods.

Effects of the inotrope DPI 201-106 on cardiac performance following cardiac surgery.

The haemodynamic, cardiac metabolic and electrocardiographic effects of the intravenous inotropic agent DPI 201-106, in 20 and 40 milligram doses, were studied in patients after coronary arterial bypass grafting. The patients were randomly allocated to receive placebo or DPI 201-106. Those receiving the active drug received either the 20 or the 40 milligram dosages of DPI 201-106. Both the placebo and the active drug were infused over 20 minute periods. Two baseline readings confirmed haemodynamic stability, and readings were taken immediately following the infusions and then at 20 minutes and at 40 minutes afterwards. Comparison of all the haemodynamic and metabolic data did not reveal any significant intra or inter group differences. Comparison of the electrocardiographic data revealed some differences. Patients receiving DPI 201-106 showed prolongation of the QTc interval immediately following the infusions. Changes in ST segments and T waves were observed. Independent analysis of the affected electrocardiographs reported that the changes were suggestive of, but not pathognomonic of, myocardial ischaemia. The metabolic data showed that the electrocardiographic changes were not associated with any evidence of anaerobic metabolism. The indication for DPI 201-106 as a positive inotropic agent in patients following coronary revascularization surgery was not established.

The impact of age on 6-month survival in patients with cardiovascular risk factors undergoing elective non-cardiac surgery.

An increasing number of patients aged>or=70 years are presenting for elective non-cardiac surgery. We undertook this study to: (i) compare the nature and distribution of cardiovascular disease (CVD) risk factors in an at risk population of patients aged>or=70 years undergoing elective surgery compared with a younger at risk cohort; and (ii) identify the impact of age and other risk factors on 6-month survival. We conducted a prospective observational study of patients undergoing elective non-cardiac surgery. A total of 1622 patients aged>or=40 years with recognised surgical or patient-specific risk factors for CVD were identified. The patients were divided into two groups; group 1 (aged: 40-69 years) and group 2 (aged>or=70 years). Logistic regression was used to identify the factors associated with 6-month mortality. Odds ratios (OR) and 95% confidence interval (CI) are presented. In hospital, mortality was similar in both groups. However, 6-month mortality in those aged>or=70 years was significantly higher (p=0.001). Cardiovascular symptoms were significantly more common in group 2 (p<0.001) as were cardiovascular-related deaths (p=0.04) at 6 months follow-up. Preoperative cardiovascular preventative therapy was under prescribed in the elderly cohort. Factors independently associated with 6-month mortality were aged>or=70 (OR=3.57, 95% CI: 2.22-5.73), angina (OR=2.0, 95% CI: 1.26-3.20), renal impairment (OR=2.39, 95% CI: 1.17-4.89) also operation type and duration. Despite similar in-hospital mortality, those aged>or=70 years had significantly higher 6-month mortality than the younger surgical cohort. Cardiovascular deaths were significantly higher in patients aged>or=70 years. Effective identification and the management of cardiovascular risk factors may improve 6-month survival.

Effects of variable dose milrinone in patients with low cardiac output after cardiac surgery. European Multicenter Trial Group.

We studied 99 adult patients after elective cardiac surgery who had low cardiac output (cardiac index less than 2.5 L/min/m2) in spite of adequate cardiac filling pressure (pulmonary capillary wedge pressure less than 8 mm Hg). Patients received milrinone by loading dose (50 micrograms/kg over a 10-minute period), followed by a continuous infusion of either 0.375, 0.5, or 0.75 micrograms/kg/min (low-, middle-, and high-dose groups, respectively) given for a minimum of 12 hours. Patients were allocated to each dosage group sequentially, not randomly. Hemodynamic measurements were made before the loading dose and at 15, 30, 45, and 60 minutes, 3, 6, and 12 hours after the start of milrinone therapy. Further measurements were made at 2 and 4 hours after treatment was stopped. Milrinone therapy was associated with a rapid, well-sustained, and highly significant increase in cardiac index in all three dose groups (p less than 0.001), and a similar fall occurred in pulmonary capillary wedge pressure in all groups (p less than 0.001). Significant increases occurred in heart rate in all three groups (p less than 0.001). Systemic and pulmonary vascular resistance also fell significantly, although changes in this latter parameter were less predictable and more dose dependent. Few serious treatment-related adverse effects were seen. We conclude that intravenous milrinone is an effective and safe therapy for the treatment of low output states after cardiac surgery.

Intravenous milrinone following cardiac surgery: I. Effects of bolus infusion followed by variable dose maintenance infusion. The European Milrinone Multicentre Trial Group.

The hemodynamic and adverse effects of intravenous milrinone were studied in 99 adult patients (66 men) following elective myocardial revascularization, mitral and/or aortic valve surgery. All patients had a low cardiac output (cardiac index [CI] mean 1.93, range, 1.11 to 2.5 L/min/m2) despite adequate cardiac filling pressure (mean pulmonary capillary wedge pressure [PCWP] 11.5 mmHg, range, 8 to 20 mmHg). Following a period of baseline stability (mean 17.8 minutes, range, 10 to 50 minutes), patients received a bolus infusion of 50 micrograms/kg over 10 minutes. A continuous maintenance infusion of 0.375 (low), 0.5 (mid) or 0.75 (high) micrograms/kg/min was administered for a minimum of 12 hours. Patients were allocated to each dosage group sequentially, not randomly. Hemodynamic measurements were made before the start of milrinone and 15 minutes after the bolus infusion. Further measurements were made at 30, 45, and 60 minutes, and at 3, 6, and 12 hours after the start of treatment. Measurements were also made at 2 and 4 hours after treatment was stopped. The bolus infusion caused significant increases in CI, heart rate (HR), and stroke index (SI), (P < 0.001), and significant falls in PCWP, right atrial pressure (RAP), mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR), mean arterial pressure (MAP), and systemic vascular resistance (SVR) (P < 0.001). These effects were maintained to a significant degree by each of the three maintenance infusion regimens, although the pulmonary vasodilator effects appeared less predictable and more dose dependent. Eighteen patients (19%) had arrhythmias; 16 of these were judged not to be serious events. Two were deemed serious; these were both episodes of fast atrial fibrillation (AF).(ABSTRACT TRUNCATED AT 250 WORDS)

Intravenous milrinone following cardiac surgery: II. Influence of baseline hemodynamics and patient factors on therapeutic response. The European Milrinone Multicentre Trial Group.

Further analysis of the data from 99 adult patients who received an intravenous infusion of milrinone following elective cardiac surgery was done. All patients received a bolus infusion of 50 micrograms/kg over 10 minutes, followed by a maintenance infusion of either 0.375, 0.5 or 0.75 microgram/kg/min for a period of 12 hours. Hemodynamic measurements were made after the bolus infusion (15 minutes), and then after 30, 45, and 60 minutes at 3, 6, and 12 hours, and 4 hours after treatment was stopped. The following was found: (1) pretreatment cardiac index (CI) affected the response to treatment. Patients with a low CI (1.59 L/min/m2) had a 54% increase after the bolus infusion compared to a 27% increase in patients with a higher pretreatment value (2.2 L/min/m2) (P < 0.05); (2) patients with a high resting level of pulmonary vascular resistance (PVR > 200 dynes.sec.cm-5) had a greater response to treatment (26% fall in PVR) than the remainder (9% fall in PVR) after 60 minutes; (3) patients with a low pretreatment mean arterial pressure (MAP) (n = 17, MAP 64 mmMg, range, 52 to 70) showed no fall in MAP following treatment, but showed a significant increase in CI (+55%). A good therapeutic response was found that was similar in patients undergoing valve replacement surgery or coronary artery bypass graft surgery, and in patients in sinus rhythm or atrial fibrillation before treatment. It is concluded that the therapeutic response to intravenous milrinone following cardiac surgery is partially determined by pretreatment hemodynamics.

A case of status epilepticus. Use of thiopentone and IPPV to control otherwise refractory convulsions.

A case of status epilepticus which was refractory to conventional anticonvulsants is described. The total dosage of thiopentone necessary to control the convulsions is greater than that previously reported. The use of regular plasma estimation of thiopentone levels, and of cortical monitoring with the Cerebral Function Monitor (Ormed Engineering) is described, and is recommended where anticonvulsants are used for prolonged control of status epilepticus and in dosages greater than is common practice.

A comparison between the effects of fentanyl, droperidol with fentanyl, and halothane anaesthesia on intra-ocular pressure in adults.

The effects of fentanyl 3.0 micrograms/kg (group 1), droperidol 0.1 mg/kg with fentanyl 3.0 micrograms/kg (group 2), and halothane 0.5% inspired concentration (group 3) on intra-ocular pressure were compared. In each group, a decrease in intra-ocular pressure was produced which was significantly lower than resting values (p greater than 0.01) and was independent of changes in arterial blood pressure. The recovery time in group 1 patients was significantly less than that of patients in group 3.

Bladder temperature as an estimate of body temperature during cardiopulmonary bypass.

Bladder temperature measured by a thermistor-tipped urinary catheter, was compared to oesophageal, nasopharyngeal, rectal and cutaneous temperatures in 33 patients during cardiopulmonary bypass. The bladder site was warmer than all other monitored sites in the pre-bypass period and showed least variation in temperature. The rate of change of bladder temperature during cooling and rewarming on bypass was significantly (p less than 0.01) lower than for oesophageal and nasopharyngeal temperatures, but was greater than or similar to the rate of change of rectal and cutaneous temperatures. This method of temperature measurement was found to be satisfactory during major surgery and also during the postoperative period in the intensive care unit.

Failure of diazepam to prevent the suxamethonium-induced rise in intra-ocular pressure.

The effects of intravenous suxamethonium chloride (1 mg/kg) on intra-ocular pressure (IOP) were studied following pretreatment with diazepam 0.05 mg/kg, tubocurarine 0.05 mg/kg, and in a control group, at induction of anaesthesia. In all three groups, a significant increase in IOP was seen during the induction sequence. In a further study, the effects of intravenous suxamethonium chloride (1 mg/kg) on IOP were studied following a period of stable general anaesthesia and pretreatment with diazepam 0.05 mg/kg. A significant rise in IOP was again seen following the administration of suxamethonium. The authors conclude that neither of the techniques described herein will reliably and predictably prevent the rise in IOP seen following the use of suxamethonium.

Thermodilution cardiac output measurements during conventional and high-frequency ventilation.

The thermodilution method for cardiac output determinations correlates well with Fick and dye dilution methods. Experimental work with thermodilution techniques has shown that individual measurements of right heart cardiac output during conventional ventilation vary throughout the respiratory cycle. The aims of this study were to compare thermodilution cardiac output determinations made at a fixed point (zero end-expiratory pressure [ZEEP]) with those made randomly throughout the respiratory cycle during conventional controlled positive pressure ventilation (CPPV) and high-frequency jet ventilation (HFJV) with up to 10 cm H2O positive endexpiratory pressure (PEEP). There were no statistically significant differences between the cardiac output determinations made at ZEEP and randomly in the ventilation cycle in any group and all correlations were significant. The clinical implications of these results are discussed, and it is concluded that it is not necessary to time the measurements of thermodilution cardiac output determinations during CPPV or HFJV with up to 10 cm H2O of PEEP.

Effect of pretreatment with propranolol on intra-ocular pressure changes during induction of anaesthesia.

It is well documented that intra-ocular pressure (IOP) increases following the administration of suxamethonium and also after laryngoscopy and intubation. It is possible that there may be a final common pathway mediated by beta adrenergic transmission which leads to this pressure rise. If so, this mechanism should be inhibited by beta adrenoceptor blockade. Pretreatment with propranolol prevented a significant rise in IOP during a thiopentone, suxamethonium, intubation induction sequence. The change in IOP was even more pronounced during a thiopentone, alcuronium, intubation induction sequence as the base-line IOP was not regained, but there was significant cardiovascular depression. In both these methods the IOP did not remain stable; there was an initial reduction followed by a rise in pressure. Whether these changes in IOP are clinically important remains an open question.

Assessment of a high frequency ventilator breathing system for use in the operating theatre. An experimental and clinical study.

A breathing system capable of delivering positive pressure ventilation to the lungs at high frequencies and using anaesthetic gases and vapours is assessed. The recommended fresh gas flow at the ventilatory rates tested in this study was 100 ml kg-1. At 80 and 100 b.p.m. the system provided adequate ventilation, good oxygenation and haemodynamic stability. When compared with conventional positive pressure ventilation (CPPV), peak airway pressure (peak Paw) was lower and mean airway pressure (Paw) was lower (80 b.p.m.) or unchanged (100 b.p.m.). There was some inherent positive end-expiratory pressure (PEEP) associated with the technique.