Intra-operative segmental wall motion abnormalities (SWMA) detected by transoesophageal echocardio- graphy (TOE) have been shown to be a sensitive indicator of myocardial ischaemia. To determine the incidence and characteristics of segmental wall motion abnormalities and to relate these changes to peri-operative myocardial ischaemia, biplane TEE, electrocardiogram (ECG) (II + V5) and pulmonary capillary wedge pressure (PCWP) were continuously monitored in 62 consecutive patients with ischaemic heart disease undergoing non-cardiac surgery. Short-axis view at mid-papillary level in transverse scan (T-scan) and long-axis in longitudinal (L-scan) two-chamber view were used for wall motion analysis. New segmental wall motion abnormalities were detected in 16 of 64 patients (25%) using biplane transoesophageal echocardiography. Monoplane transoesophageal echocardiography showed a sensitivity of 75% and a specificity of 100%, electrocardiogram two lead showed a sensitivity of 56% and a specificity of 98%, whereas pulmonary capillary wedge pressure had a sensitivity of 25%, and a specificity of 93% and pressure rate quotient (PRQ) < 1 demonstrated sensitivity of 19% and a specificity of 92% in the detection of myocardial ischaemia. It is concluded that the long-axis view of the left ventricle provides additional information for the detection of segmental wall motion abnormalities. Neither changes in haemodynamic performance nor in electrocardiography leads II and V5 match those of transoesophageal echocardiography for the identification of myocardial ischaemia.

This case report describes the peri-operative management of a 48-year-old woman with three cerebral aneurysms and phaeochromocytoma. The pharmacological and anaesthetic management of such patients is complex, and needs to be managed carefully by titrating anaesthetic agents and vasoactive drugs. The primary concern is the maintenance of cerebral perfusion pressure and autoregulation throughout the procedure, although these states cannot be monitored directly. The patient survived the operation neurologically intact, and it is presumed that the course of management which was chosen helped to achieve this result.

Summary

Background and objective: The aim was to study the rapid changes in cardiac output and systemic vascular resistance produced by intravenous epinephrine (5 μg) on a beat-by-beat basis.

Methods: Ten patients were studied during cardiac surgery. Radial or brachial arterial pressure was recorded continuously during intravenous administration of epinephrine (5 μg). Cardiac output and systemic vascular resistance were derived for each beat using arterial pulse contour analysis calibrated by lithium indicator dilution. In each patient a further dose of epinephrine (5 μg) was administered during cardiopulmonary bypass with the blood flow kept constant so that changes in arterial pressure corresponded to changes in systemic vascular resistance.

Results: When the patients were not on cardiopulmonary bypass, the epinephrine produced an initial increase in systemic vascular resistance to 129 ± 15% (mean ± SD) of control, followed by a more prolonged reduction to 57 ± 13% of control. Cardiac output showed a small initial reduction coincident with the increase in systemic vascular resistance, followed by an increase to 152 ± 24% of control. During cardiopulmonary bypass, the changes produced by epinephrine on systemic vascular resistance were qualitatively similar but smaller in amplitude, probably because of a greater volume of dilution in the bypass circuit.

Conclusions: Small bolus doses of epinephrine produce an initial increase in systemic vascular resistance followed by a much greater reduction that may cause hypotension.

Summary

Background and objective: This prospective observational study analyses cardiovascular changes in adult patients with acute respiratory distress syndrome (ARDS) during transition from pressure-controlled ventilation to high-frequency oscillatory ventilation (HFOV), using transoesophageal echocardiography (TOE) and invasive haemodynamic monitoring.

Methods: Nine patients (median age 65 years; range 42–70) with ARDS were studied. HFOV was started and maintained with an adjusted mean airway pressure of 5 cmH2O above the last measured mean airway pressure during pressure-controlled ventilation. Haemodynamic and TOE measurements were performed in end-expiration during baseline pressure-controlled ventilation, and again 5 and 30 min after the start of during uninterrupted HFOV.

Results: Right atrial pressure increased immediately (P = 0.004). After 30 min, pulmonary arterial occlusion pressure increased (P = 0.008), cardiac index decreased (P = 0.01), stroke volume index decreased (P = 0.02) and both left ventricular end-diastolic and end-systolic area indices decreased (P = 0.02). Fractional area change, left ventricular end-systolic wall stress, heart rate, mean arterial pressure and mean pulmonary artery pressure remained unchanged.

Conclusions: Transition to HFOV at a mean airway pressure of 5 cmH2O above that during pressure-controlled ventilation induced significant, but clinically minor, haemodynamic effects, which are most probably due to airway pressure-related preload reduction.

Summary

Background and objective: The study compared the analgesic efficacy and safety of two preoperatively administered cyclo-oxygenase-2 inhibitors, celecoxib and rofecoxib.

Methods: Ninety adult patients undergoing thyroid surgery were divided into three groups (each n = 30). They were given a single oral dose of placebo, celecoxib 200 mg or rofecoxib 50 mg 1 h before induction of anaesthesia. All patients received a standard anaesthetic. Intraoperative blood loss was measured. Pain scores, sedation scores, heart rate, mean arterial pressure and respiratory rate were noted at 0, 1, 2, 4, 6, 12 and 24 h postoperatively. Analgesic (meperidine) requirements and adverse effects were recorded during the first postoperative 24 h.

Results: Compared with placebo, pain scores were significantly lower with rofecoxib at all time points (P < 0.05) and were significantly lower with celecoxib (P < 0.05) during the first 4 h. Pain scores were significantly lower with rofecoxib compared with celecoxib at 6, 12 and 24 h (P < 0.05). The average cumulative 24 h meperidine dose was significantly lower with both celecoxib (54.9 ± 34.4 mg) and rofecoxib (42.8 ± 40.9 mg) compared with placebo (76.8 ± 6.2 mg) (P < 0.01 and P < 0.001, respectively). There were no differences in the intraoperative blood loss, heart rate, mean arterial pressure, respiratory rate, sedation scores and incidence of adverse effects among groups.

Conclusions: The preoperative administration of rofecoxib 50 mg and less so of celecoxib 200 mg provide a significant analgesic benefit with regard to postoperative pain relief and decrease in additional opioid requirements after thyroid surgery.

Subarachnoid haemorrhage (SAH) following cerebral aneurysm rupture or trauma can result in the induction of secondary ischaemic brain damage via a decrease in microvascular perfusion, a disruption of the blood-brain barrier and consequent vasogenic oedema, and the delayed spasm of the major cerebral arteries (i.e. vasospasm). It is increasingly apparent that oxygen radical-induced, iron-catalyzed lipid peroxidation (LP) within the subarachnoid blood and vascular wall plays a key role in the occurrence of these secondary events. Tirilazad mesylate is a potent cytoprotective inhibitor of LP that works by a combination of radical scavenging and membrane stabilizing properties. It has been demonstrated to attenuate the acute and delayed vascular consequences of SAH and to protect the brain against ischaemic insults. Much of its action is mediated by an effect on the vascular endothelium, although it also appears to exert some direct neuroprotection and to inhibit LP in the subarachnoid blood. These actions of tirilazad in experimental SAH are reviewed.

Summary

Background and objective: Aprotinin administration may decrease the incidence of stroke associated with coronary artery bypass surgery by an unknown mechanism. Astrocytes exposed to hypoxia produce proinflammatory cytokines and upregulate intercellular adhesion molecule (ICAM)-1 on cerebral endothelium. This study investigated the effects of aprotinin on cerebral endothelial activation by hypoxic astrocytes in vitro.

Methods: Mouse astrocytes were exposed to hypoxia in an anaerobic chamber for 4 h followed by reoxygenation for 24 h. Astrocyte-conditioned medium (ACM) collected from mouse astrocytes subjected to hypoxia/reoxygenation (HR) or normoxia were applied to mouse cerebral endothelial cell (MCEC) cultures for 4 and 24 h in normoxia. Endothelial cells were preincubated for 1 h with aprotinin (1600 KIU mL−1) prior to exposure to ACM. Flow cytometry was used to estimate endothelial ICAM-1 expression. Interleukin (IL)-1β space concentrations in ACM were estimated with enzyme-linked immunosorbent assay (ELISA). Repeated comparisons were made using analysis of variance (ANOVA) and post hoc Tukey test as appropriate. P < 0.05 was considered significant. Data is presented as mean (standard deviation, SD).

Results: MCEC ICAM-1 expression was greater after 24 h exposure to HR-ACM compared to normoxic-ACM (mean channel flouresence (MCF) 107.5 (4.5) vs. 74.3 (4.5), respectively, P < 0.001). ICAM-1 expression was decreased by aprotinin preincubation compared to control (MCF 91.0 (1.1) vs. 107.5 (2.1), P = 0.006). Supernatant IL-1β concentrations in astrocytes exposed to HR were greater than those exposed to normoxia (7.1 (0.2) vs. 4.1 (0.2), P = 0.01).

Conclusions: This may be a neuroprotective mechanism associated with aprotinin administration.

Fifteen patients undergoing elective thoracic surgery were studied in order to investigate the efficacy of high frequency jet ventilation of the non-dependent lung with respect to arterial oxygenation. During the study PaO2, PaCO2, arterial pressures and heart rate were recorded during ventilation of both lungs in the lateral decubitus position during one-lung ventilation and during high frequency jet ventilation of the non-dependent lung. Mean PaO2 was 28±8.75 kPa and mean PaCO2 was 5.4±0.7 kPa during control. During one-lung ventilation, PaO2 dropped to 10.8±2.57 kPa and PaCO2 rose to 6.3±0.9 kPa. With high frequency jet ventilation to the non-dependent lung, mean PaO2 increased to 25±6.75 kPa and PaCO2 decreased to 5.16±0.9 kPa respectively. Arterial pressures and heart rate remained stable during the study period. In conclusion high frequency jet ventilation of the non-dependent lung was effective in providing arterial normoxaemia and normocapnia during one-lung ventilation.

Summary

Background and objective: In October 2000, we conducted a national postal survey of day case consultant anaesthetists in the UK to explore the range and variation in practice of anaesthetizing a patient for day case surgery (paediatrics, urology and orthopaedics). This paper reports the findings of this national survey of paediatric day case anaesthetic practice carried out as part of a major two-centre randomized controlled trial designed to investigate the costs and outcome of several anaesthetic techniques during day care surgery in paediatric and adult patients (cost-effectiveness study of anaesthesia in day case surgery).

Methods: The survey used a structured postal questionnaire and collected data on the duration of surgical procedure; the use of premedication; the anaesthetic agents used for induction and maintenance; the fresh gas flow rates used for general anaesthesia; the use of antiemetics; and the administration of local anaesthesia and analgesia.

Results: The overall response rate for the survey was 74 and 63% for the paediatric section of the survey. Respondents indicated that 19% used premedication, 63% used propofol for induction, 54% used isoflurane for maintenance, 24% used prophylactic antiemetics and 85% used a laryngeal mask. The findings of this national survey are discussed and compared with published evidence.

Conclusions: This survey identifies the variation in clinical practice in paediatric day surgery anaesthesia in the UK.