Automated versus manual blood pressure measurement: a randomized crossover trial

This study evaluated the accuracy and reliability of the Dinamap 8100 automated blood pressure machine against three internationally recognized criteria. Systolic and diastolic blood pressures were taken concurrently by two nurses using the automated machine and a manual sphygmomanometer. Results demonstrated agreement between automated and manual readings on one set of criteria for both systolic and diastolic pressures, and support for systolic readings only on one other criterion. Comparison of mean differences between automated and manual measures showed the automated machine consistently under-read both systolic and diastolic blood pressures. The conclusion from this study was that the Dinamap 8100 machine can be used with some degree of confidence to assess systolic blood pressures in a general population of adult hospital inpatients, but with caution when taking diastolic readings.     

Ageism revisited: a study measuring ageism in East Tennessee, USA

Abstract   Research literature over the past 50 years has addressed ageism, but few studies have examined the measurement of ageism or how to combat it. This study utilized Palmore's Ageism Survey to measure the frequency of occurrence of ageism and to examine the types of ageism reported by older adults in the East Tennessee region of the USA. A convenience sample of 247 community-dwelling older adults was recruited from eight senior centers and nutrition sites. The participants ranged in age from 60–92 years. Eighty-four percent of the participants indicated an experience with at least one type of ageism. The forms of ageism frequently reported were jokes and birthday cards that poked fun at older people. Events showing disrespect also were reported. Differences in urban/suburban and rural reporting were noted. The findings from this and similar studies might provide guidance for the measurement of ageism and how to combat it.     

Determining the effectiveness of mental health services from a consumer perspective: part 2: barriers to recovery and principles for evaluation

The routine use of standardized outcome measures has been introduced to assess the effectiveness of mental health service delivery throughout Australia. The use of these measures has been criticized for failing to reflect those aspects of treatment consumers consider to affect their recovery. This is the second of a two-part paper. Its aim is to explore the views of consumers regarding factors that impede recovery and to explore the principles that ideally should underpin the evaluation of mental health services. Focus group interviews were conducted with consumers of mental health services (n = 16) from one rural and one metropolitan mental health service in Victoria, Australia. This paper presents the findings, pertaining to aspects of mental health services that pose barriers to recovery. The main themes to emerge were: staffing issues; hearing the person not the illness; lack of safety and security; and, isolation. The main themes to emerge regarding the evaluation of mental health services were: consumer involvement; peer support and more responsive care and treatment. The views of participants suggest that the effective evaluation of mental health services requires an increased focus on the views and opinions of consumers in order to develop more responsive mental health services.     

Growth rate of non-operated meningiomas

INTRODUCTION: Meningiomas are dural-based brain tumors that are typically histologically benign. Some meningiomas grow slowly or seemingly not at all with planimetric measurement. Volumetric measurement may be more accurate because tumors may grow in different directions than the planimetric axes. METHODS: Twenty-one patients (with 22 tumors) had serial MRI brain scans available for review. We reviewed the charts and measured tumor dimensions on the MRI scans. Relative growth rates were calculated for volume and maximum initial diameter using published formulas. Patient demographics, tumor location, and special radiologic characteristics (calcification, T2 hypointensity, dural tail, mass effect, and midline shift) were compared to the volumetric growth rate. RESULTS: Patients included 17 females and 4 males; age at diagnosis 36 to 74 years (mean 61). Follow-up was 2.08 to 10.83 years (mean 3.64). Most tumors were located in the convexity (27.27 %), sphenoid wing (27.27 %), or cerebellopontine angle (13.04 %). Two meningiomas (9.09 %) demonstrated no growth. The mean relative volumetric growth rate was 5.82 %/year, and planimetric was 2.00 %/year (difference 3.82 %/year, p-value < 0.0001). Convexity location had near significant association with slower relative volumetric growth. There were no significant associations between other tumor locations, age, gender, or radiologic characteristics and volumetric growth. CONCLUSIONS: The mean volumetric growth rate was significantly greater than the planimetric growth rate, suggesting that volumetric measurement conveys more information and is superior in assessing tumor growth. This information could have clinical value in determining the frequency of follow-up imaging and the urgency of surgical intervention.     

Hemiarthroplasty of the hip for fracture-what is the appropriate sized femoral head?

INTRODUCTION: Caliper measurement of the excised femoral head is a standard technique for determination of prosthetic head size during hemiarthroplasty for displaced femoral neck fractures. OBJECTIVES: To evaluate the accuracy of the caliper method of hemiarthroplasty head sizing by comparing it to the native joint congruency (JC) at the weight bearing surface. MATERIALS AND METHODS: The diameters of femoral heads in 10 cadaver hip joints were measured by using a caliper at the head equator. Cast moulds were prepared from both the acetabulum and the femoral head in each joint. Every mould's exact spherical diameter at the weight bearing region was measured by a computerised coordinate measuring machine (MNC B231 MITUTOYO). All specimens were coded to ensure that future examination was carried out in a blind manner. Native JC mismatch was determined by subtracting the diameter of the femoral cement mould from that of the acetabular one. Similarly, JC mismatch was calculated for the caliper measurements. RESULTS: The average native JC mismatch (0.36+/-0.29mm, range 0.03-0.82mm, median 0.29mm) was found significantly smaller (p=0.03) than following caliper measurements (0.72+/-0.37mm, range 0.37-1.46mm, median 0.6mm). Routine caliper measured downward size rounding enhanced (p=0.004) this mismatch (0.98+/-0.44mm, range 0.37-1.96mm, median 1.01mm), while upward rounding (0.48+/-0.46mm, range -0.06 to 1.15mm, median 0.41mm) helped mitigate this tendency. CONCLUSIONS: Caliper measurements tend to undersize the actual sphere diameter of the femoral head at the weight bearing region. Upward rounded prosthesis should be selected in order to compensate for this propensity.     

Similarity between the suprasystolic wideband external pulse wave and the first derivative of the intra-arterial pulse wave

BACKGROUND: Wideband external pulse (WEP) monitoring, using a broad bandwidth piezoelectric sensor located over the brachial artery under the distal edge of a sphygmomanometer cuff, can be used for evaluating the contour of the arterial pressure pulse wave. The pulse contour contains valuable information relating to cardiovascular function which may be of clinical use in addition to blood pressure measurements. The aim of this study was to compare the shape of the WEP signal during inflation of the cuff to suprasystolic pressure, with intra-arterial pressure waves, after the administration of vasoactive drugs. METHODS: Radial intra-arterial and suprasystolic WEP waveforms were recorded in 11 healthy men (mean 23 yr) before and at the end of infusion of glyceryl trinitrate, angiotensin II, norepinephrine, and salbutamol. Waveform similarity was assessed by comparing the timing and pressure of incident and reflected waves and by root mean square error (RMSE). RESULTS: The WEP signal was found to closely resemble the first derivative of intra-arterial pressure. The WEP signal could be used to derive an arterial pressure wave with minimal bias in the timing of incident [- 8 (18) ms, mean (SD)] and reflected [- 1 (24) ms] waves. Augmentation index was underestimated by WEP [- 7 (18)%]. WEP also provided a measure of compliance which correlated with pulse wave velocity (r = - 0.44). RMSE values after the administration of each of the four drugs mentioned earlier were 12.4 (3.8), 17.7 (5.0), 22.1 (11.7), and 28.9 (22.4) mm Hg, respectively. Changes in derived WEP signals were similar to those measured by arterial line with all drugs. CONCLUSIONS: The suprasystolic WEP signals can be used to derive arterial pressure waves which, although not identical, track changes in the intra-arterial pulse wave induced by vasoactive drugs.     

Semi-invasive monitoring of cardiac output by a new device using arterial pressure waveform analysis: a comparison with intermittent pulmonary artery thermodilution in patients undergoing cardiac surgery

BACKGROUND: Thermodilution technique using a pulmonary artery catheter (PAC)is a widely used method to determine cardiac output (CO). Itis increasingly criticized because of its invasiveness and itsunclear risk–benefit ratio. Thus, less invasive techniquesfor measuring CO are highly desirable. We compared a new, semi-invasivedevice (FloTrac/Vigileo^TM) using arterial pressure waveformanalysis for CO measurement in patients undergoing cardiac surgerywith bolus thermodilution measurements. METHODS: Forty patients undergoing coronary artery bypass grafting orvalve repair were enrolled. A PAC was inserted and routine radialarterial access was used for semi-invasive determination ofCO with the Vigileo. CO was measured simultaneously by bolusthermodilution and the Vigileo technique after induction ofanaesthesia (T1), before cardiopulmonary bypass (CPB) (T2),after CPB (T3), after sternal closure (T4), on arrival in theintensive care unit (ICU) (T5), and 4 h (T6), 8 h(T7), and 24 h after surgery (T8). CO was indexed to thebody surface area (cardiac index, CI). RESULTS: A total of 244 pairs of CI measurements were analysed. Biasand precision (1.96 SD of the bias) were 0.46 litre min^–1m^–2 and ± 1.15 litre min^–1 m^–2 (r =0.53) resulting in an overall percentage error of 46%. Subgroupanalysis revealed a percentage error of 51% for data pairs obtainedintraoperatively (T1–T4), 42% in ICU (T5–T8), and56% for values obtained during low CI (T1–T8). CONCLUSIONS: In cardiac surgery patients, CO measured by a new semi-invasivearterial pressure waveform analysis device showed only moderateagreement with intermittent pulmonary artery thermodilutionmeasurement.     

Effect of epinephrine on epidural, intrathecal, and plasma pharmacokinetics of ropivacaine and bupivacaine in sheep

BACKGROUND: Local vasoconstriction induced by epinephrine added to epidural local anaesthetics has been shown to improve their quality and duration of action in several clinical reports. There are several assumptions on the mechanisms. This study was designed to evaluate the influence of epinephrine on transmeningeal uptake of epidurally administered ropivacaine and bupivacaine by measuring local anaesthetic concentrations in the epidural and intrathecal spaces and in plasma. METHODS: Ropivacaine (50 mg) and bupivacaine (30 mg) were administered epidurally in sheep with and without epinephrine (75 microg). A microdialysis technique was used to simultaneously measure epidural and intrathecal drug concentrations. Resulting dialysate and plasma concentrations were used to calculate pharmacokinetic parameters for ropivacaine and bupivacaine. RESULTS: Co-administration of epinephrine decreased epidural clearance for ropivacaine [0.6 (sd 0.1) vs 0.4 (0.1) ml min(-1)] but not significantly for bupivacaine [1.2 (0.4) vs 0.8 (0.3) ml min(-1)]. The resultant increase in epidural area under the concentration-time curves (31% for ropivacaine and 52% for bupivacaine) was also observed in the intrathecal space (21% increase for ropivacaine and 37% for bupivacaine). There was no significant influence of epinephrine on ropivacaine plasma pharmacokinetics. Plasma Cmax for bupivacaine was decreased. CONCLUSIONS: These results show that epinephrine decreases the clearance and distribution processes involved in epidural disposition of ropivacaine and bupivacaine, leading to an increased uptake into the intrathecal space with an apparent more pronounced effect for bupivacaine.     

Measurement of cardiac output: a comparison between transpulmonary thermodilution and uncalibrated pulse contour analysis

Background: Recently, continuous monitoring of cardiac output (CO) basedon pulse contour analysis (Vigileo^®) has been introducedinto practice. In this clinical study, we evaluated the accuracyof this system by comparing it with the transpulmonary thermodilutiontechnique (TPID) in septic patients. Methods: We studied 24 mechanically ventilated patients with septic shock(16 male, 8 female, age 26–77 yr) receiving treatmentwith norepinephrine who for clinical indication underwent haemodynamicmonitoring by the transpulmonary thermodilution technique usinga PiCCO^®plus system (Pulsion Medical Systems, Munich, Germany).In parallel, arterial pulse contour was applied using the femoralarterial pressure curve (FloTrac^® pressure sensor, Vigileo^®monitor, Edwards Lifesciences, Irvine, USA). After baselinemeasurement, mean arterial pressure was elevated by increasingnorepinephrine dosage, and CO was measured again before meanarterial pressure was reduced back to baseline levels. Fluidstatus and ventilator settings remained unchanged throughout.At each time point, CO by transpulmonary thermodilution wascalculated from three central venous bolus injections of 15ml of saline (<8°C). Linear regression and the Bland–Altmanmethod were used for statistical analysis. Results: Overall, CO was 6.7 (SD 1.8) (3.2–10.1) litre min^–1for CO(TPID) and 6.2 (2.4) (3.0–17.6) litre min^–1for CO(Vigileo^®). Linear regression revealed: CO(Vigileo^®)= 1.54 + 0.72 x CO(TPID) litre min^–1, r² = 0.26 (P <0.0001). Mean bias between techniques [CO(TPID)–CO(Vigileo^®)]was 0.5 litre min^–1 (SD 2.3 litre min^–1). Correlationcoefficients at the three time points were not significantlydifferent from each other. Conclusions: Pulse contour analysis-derived CO (Vigileo^® system) underestimatesCO(TPID) and is not as reliable as transpulmonary thermodilutionin septic patients.