A validation study of the CEMACH recommended modified early obstetric warning system (MEOWS)

The 2003-2005 Confidential Enquiry into Maternal and Child Health report recommended the introduction of the modified early obstetric warning system (MEOWS) in all obstetric inpatients to track maternal physiological parameters, and to aid early recognition and treatment of the acutely unwell parturient. We prospectively reviewed 676 consecutive obstetric admissions, looking at their completed MEOWS charts for triggers and their notes for evidence of morbidity. Two hundred patients (30%) triggered and 86 patients (13%) had morbidity according to our criteria, including haemorrhage (43%), hypertensive disease of pregnancy (31%) and suspected infection (20%). The MEOWS was 89% sensitive (95% CI 81-95%), 79% specific (95% CI 76-82%), with a positive predictive value 39% (95% CI 32-46%) and a negative predictive value of 98% (95% CI 96-99%). There were no admissions to the intensive care unit, cardio respiratory arrests or deaths during the study period. This study suggests that MEOWS is a useful bedside tool for predicting morbidity. Adjustment of the trigger parameters may improve positive predictive value.

Virtual reality, ultrasound-guided liver biopsy simulator: development and performance discrimination

OBJECTIVES

The aim of this article was to identify and prospectively investigate simulated ultrasound-guided targeted liver biopsy performance metrics as differentiators between levels of expertise in interventional radiology.

METHODS

Task analysis produced detailed procedural step documentation allowing identification of critical procedure steps and performance metrics for use in a virtual reality ultrasound-guided targeted liver biopsy procedure. Consultant (n=14; male=11, female=3) and trainee (n=26; male=19, female=7) scores on the performance metrics were compared. Ethical approval was granted by the Liverpool Research Ethics Committee (UK). Independent t-tests and analysis of variance (ANOVA) investigated differences between groups.

RESULTS

Independent t-tests revealed significant differences between trainees and consultants on three performance metrics: targeting, p=0.018, t=-2.487 (-2.040 to -0.207); probe usage time, p = 0.040, t=2.132 (11.064 to 427.983); mean needle length in beam, p=0.029, t=-2.272 (-0.028 to -0.002). ANOVA reported significant differences across years of experience (0-1, 1-2, 3+ years) on seven performance metrics: no-go area touched, p=0.012; targeting, p=0.025; length of session, p=0.024; probe usage time, p=0.025; total needle distance moved, p=0.038; number of skin contacts, p<0.001; total time in no-go area, p=0.008. More experienced participants consistently received better performance scores on all 19 performance metrics.

CONCLUSION

It is possible to measure and monitor performance using simulation, with performance metrics providing feedback on skill level and differentiating levels of expertise. However, a transfer of training study is required.

Shuttle imaging radar experiment

The shuttle imaging radar (SIR-A) acquired images of a variety of the earth's geologic areas covering about 10 million square kilometers. Structural and geomorphic features such as faults, folds, outcrops, and dunes are clearly visible in both tropical and arid regions. The combination of SIR-A and Seasat images provides additional information about the surface physical properties: topography and roughness. Ocean features were also observed, including large internal waves in the Andaman Sea.

Incidence and Effect of Bare Suprarenal Stent Struts Crossing Renal Ostia Following EVAR

OBJECTIVES

The incidence and effect of bare stent struts crossing the renal ostia following endovascular aortic aneurysm repair with the Talent stent-graft is not known. The study aims to establish the incidence in which bare stent struts cross the renal ostia and to assess any associated effects on renal function.

METHODS

Fifty-five patients (51 men, mean age 73 years, range 57-90) who had endovascular repair of their abdominal aortic aneurysms with a Talent suprarenal stent-graft were included in the study. Patients were scanned at a variety of follow-up periods (median 24 months, range 3-102). The relationship between the bare stent struts and the renal ostia, together with renal function were retrospectively recorded. The presence and location of the bare stent struts was assessed using CT virtual intravascular endoscopy (CT VIE). Struts were defined as being absent, peripherally located or in the central channel of the renal ostia. Renal function was assessed from glomerular filtration rates (GFR) derived from serum creatinine levels and the Cockcroft and Gault formula.

RESULTS

A total of 109 renal ostia were evaluated by CT VIE with one patient having a previous nephrectomy. Bare stent struts crossed 1 renal ostium in 22 (40%) patients and bilateral ostia in 5 (9%) patients. Of the 109 ostia assessed, 15 (14%) ostia were crossed centrally and 17 (16%) had struts crossing the ostium peripherally. There were no statistically significant differences in the change between pre-operative GFR and latest GFR in the group without any strut involvement (6 mLs/min +/- 7 mLs/min) and the group with struts crossing one or both renal ostia (2 mLs/min +/- 9 mLs/min; p > .05).

CONCLUSION

Peripheral or central coverage of renal ostia by bare stent struts occurs in a third of all renal arteries following EVAR. Crossing of renal ostia by bare stent struts does not affect follow-up GFR.

Troponin T after endoscopic retrograde cholangiopancreatography: no evidence of harm

BACKGROUND AND STUDY AIMS

It is well recognized that myocardial ischemia can occur during endoscopic retrograde cholangiopancreatography (ERCP). Acute arrhythmias and ST segment changes have been reported by a number of authors, but the longer-term sequelae with regard to permanent myocardial damage are not known. The aim of this study was to determine the presence or absence of significant injury to the heart muscle.

PATIENTS AND METHODS

Sixty-two patients undergoing therapeutic ERCP were assessed clinically and with electrocardiography (ECG) for the presence of ischemic heart disease before the procedure. Extensive intraprocedural monitoring was carried out, postprocedural ECGs were recorded, and serum troponin T levels were measured. The ECGs were evaluated blindly by a single cardiologist.

RESULTS

In 61 of the 62 patients, no changes were observed between the ECGs before and after the procedure. One patient had postprocedural T wave inversion but a normal troponin T level, excluding myocardial damage. One patient with mild renal insufficiency and treated heart failure had borderline troponin T elevation (0.05 microg/l) but no ECG changes. No complications of ERCP occurred.

CONCLUSIONS

Whilst ECG and rhythm changes indicating transient myocardial ischemia do occur during ERCP, there is no evidence that myocardial damage takes place as a consequence of this.

Patterns, incidence and predictive factors for pain after interventional radiology

AIM

To evaluate prospectively the pattern, severity and predictive factors of pain after interventional radiological procedures.

MATERIALS AND METHODS

All patients undergoing non-arterial radiological interventional procedures were assessed using a visual-analogue scale (VAS) for pain before and at regular intervals for 24 h after their procedure.

RESULTS

One hundred and fifty patients (87 men, mean age 62 years, range 18-92 years) were entered into the study. Significant increases in VAS score occurred 8 h after percutaneous biliary procedures (+47.7 mm, SD 14.9 mm; p=0.001), 6 h after central venous access and gastrostomy insertion (+23.7 mm, SD 19.5 mm; p=0.001 and +28.4 mm, SD 9.7 mm; p=0.007, respectively) and 4h after oesophageal stenting (+27.8 mm, SD 20.2 mm, p=0.001). Non-significant increases in VAS pain score were observed after duodenal and colonic stenting (duodenal: +5.13 mm, SD 7.47 mm; p=0.055, colonic: +23.3 mm, SD 13.10 mm, p=0.250) at a mean of 5h (range 4-6h). Patients reported a significant reduction in pain score for nephrostomy insertion (-28.4mm, SD 7.11 mm, p=0.001). Post-procedural analgesia was required in 99 patients (69.2%), 40 (28.0%) requiring opiates. Maximum post-procedural VAS pain score was significantly higher in patients who had no pre-procedural analgesia (p=0.003).

CONCLUSION

Post-procedural pain is common and the pattern and severity of pain between procedures is variable. Pain control after interventional procedures is often inadequate, and improvements in pain management are required.

Rate of 'onset' and 'offset' of four non-depolarising neuromuscular blocking drugs

There is evidence that onset time and potency of non-depolarising neuromuscular blocking drugs are related. The relationship between onset time and rate of recovery has not been investigated. In this study, using the isolated forearm technique, the onset time of four different non-depolarising drugs have been compared with their recovery times. It has been demonstrated that there is a strong relationship between these parameters. It is proposed that the relationship between onset time and offset time suggests a common mechanism that influences both events and that this may also explain the relationship between potency and the rate of onset.

Inhaled anaesthetic agents: from halothane to the present day

Despite the enormous resources spent on research and development, only two new volatile agents have been introduced into anaesthetic practice in the UK since the introduction of halothane. This article reviews their properties and looks towards changes in volatile anaesthetic availability in the near future.

Inhaled anaesthetic agents: from ether to halothane

The introduction of general anaesthesia revolutionized surgical practice. In this workshop and the one that follows in a future issue the evolution and properties of inhalational anaesthetics are reviewed and future developments are considered. Here we look at the period between the introduction of ether and of the first modern agent, halothane.