Manometric calibration of Warburg flasks and manometers and a simple calibrator for outweighing of Warburg manometers.
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Calibration↗
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Practical considerations in the choice of catheter tip manometers versus conventional fluid-filled catheter manometer systems.
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Catheterization↗
[A correction of left ventricle pressures obtained from catheter-manometer system by catheter-tip manometer (author's transl)].
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Blood Pressure↗
Measurement of arm blood pressure using different oscillometry manometers compared to auscultatory readings.
Five different semiautomatic manometers were tested, where oscillometry is the measuring principle. Three of the manometers (Omron R4, A&D UB 322 and Braun) were wrist manometers, where the occluding cuff is placed around the volar surface of the wrist. Two of the manometers (A&D UA 777 and Omron M4) measure on the upper arm. The investigation included 72 patients with systolic blood pressure (SBP) ranging between 110 and 200, and diastolic blood pressure (DBP) between 62 and 114 mmHg. Forty-five of the subjects were on antihypertensive medication when the manometer tests were carried out. Each of the manometers was tested with double measurements of blood pressure against 2 x 2 auscultatory measurements done before and after the semiautomatic readings. The auscultatory measurements are all performed by the same observer, who was blinded for the measurements with semiautomatic manometers. The mean difference between the oscillometric recordings compared to auscultatory measurements varied from +1.2 to -8.5 mmHg for SBP and from -0.5 to -8.3 mmHg for DBP. However, the interindividual differences varied considerable with standard deviation of the difference varying from 8 to 18 mmHg for SBP with the highest values for wrist manometers. Concerning DBP, the standard deviation of difference for all five manometers was between 6 and 8 mmHg, with the highest values for wrist manometers. None of the tested manometers fulfilled the criteria for grading A or B in the previously introduced grading by the British Hypertension Society. To conclude, the upper-arm manometers have a measuring accuracy for SBP a little higher than that of the wrist manometers, while there is no bigger difference in the measuring accuracy of DBP. The most important point is that the measuring accuracy in a single patient is unpredictable. If home readings are prepared, a test of the accuracy against auscultatory recordings should be done in every single patient. In the clinical wards, it is important to be aware of the measuring accuracy if oscillometric measurements are introduced replacing auscultatory measurements.
Antihypertensive Agents↗
Neonatal resuscitation 3: manometer use in a model of face mask ventilation.
BACKGROUND: Adequate ventilation is the key to successful neonatal resuscitation. Positive pressure ventilation (PPV) is initiated with manual ventilation devices via face masks. These devices may be used with a manometer to measure airway pressures delivered. The expiratory tidal volume measured at the mask (V(TE(mask))) is a good estimate of the tidal volume delivered during simulated neonatal resuscitation. AIM: To assess the effect of viewing a manometer on the peak inspiratory pressures used, the volume delivered, and leakage from the face mask during PPV with two manual ventilation devices in a model of neonatal resuscitation. METHODS: Participants gave PPV to a modified resuscitation mannequin using a Laerdal infant resuscitator and a Neopuff infant resuscitator at specified pressures ensuring adequate chest wall excursion. Each participant gave PPV to the mannequin with each device twice, viewing the manometer on one occasion and unable to see the manometer on the other. Data from participants were averaged for each device used with the manometer and without the manometer separately. RESULTS: A total of 7767 inflations delivered by the 18 participants were recorded and analysed. Peak inspiratory pressures delivered were lower with the Laerdal device. There were no differences in leakage from the face mask or volumes delivered. Whether or not the manometer was visible made no difference to any measured variable. CONCLUSIONS: Viewing a manometer during PPV in this model of neonatal resuscitation does not affect the airway pressure or tidal volumes delivered or the degree of leakage from the face mask.
Air Pressure↗
Setting safe and effective suction pressure: the effect of using a manometer in the suction circuit.
OBJECTIVES: To establish the levels of pressure used to perform tracheal suction (TS) and if they are affected by having a manometer visible in the suction circuit. DESIGN: A bench test evaluation of simulated tracheal suction. SETTING: Physiotherapy department of a major teaching hospital in Melbourne, Australia. PARTICIPANTS: Sixty-four nurses and physiotherapists who regularly apply TS to patients in the intensive care units of this hospital. INTERVENTIONS: All subjects used both circuit A (without a visible manometer) and B (with a visible manometer) in a predetermined random order. For both, subjects adjusted the suction control tap to where they said a safe and effective pressure (set pressure) was delivered and then occluded the suction catheter as though suctioning (applied pressure). Subjects then completed a questionnaire on their current TS practise. MEASUREMENTS AND RESULTS: All set pressures (mean = 228.57 mmHg) and all applied pressures (mean = 359. 52 mmHg) were significantly higher (P <.001) when compared to the expected pressures (mean = 135 mmHg). Pressures set without a visible manometer (circuit A) were significantly higher (P <.05) than those using a visible manometer (circuit B) but the applied pressures were not significantly different (P =.166). Neither the investigator (P =.618) or the test order (P =.167) had a significant effect on the outcome. Questionnaire results showed 31 % of subjects considered 100-170 mmHg a safe and effective suction pressure whilst none reported using an objective means of measuring pressure. CONCLUSION: All pressures in both circuits were significantly higher than those recommended as safe in the literature. In addition, pressures were unaffected by the inclusion of a visible manometer in the suction circuit.
Adult↗
Accuracy of a new wrist cuff oscillometric blood pressure device: comparisons with intraarterial and mercury manometer measurements.
Accurate measurement of arterial blood pressure is of great importance for the diagnosis and treatment of hypertension. Because of the chronic nature of antihypertensive drug therapy, the involvement of the patient in blood pressure control is desirable. Such an involvement, however, is only feasible if simple, user-friendly, and precise blood pressure measurement devices are available. In this study we tested a new wrist cuff oscillometric blood pressure measurement device in 100 consecutive patients undergoing cardiac catheterization. Blood pressures were simultaneously taken intraarterially (axillary artery) and with a mercury manometer and stethoscope or noninvasive measurement device (OMRON R3). Intraarterial measurements were directly compared with two measurements taken in random order with either an arm cuff mercury manometer or the wrist cuff device. Systolic and diastolic blood pressure as assessed with the mercury manometer was higher, especially when compared with the intraarterial and the wrist cuff values, which were comparable. Correlations of blood pressure values with intraarterial measurement were 0.86 systolic and 0.75 diastolic (P < .01) for the wrist cuff and 0.84 systolic (P < .01) and 0.59 diastolic (P < .05) for the mercury manometer measurements. Reproducibility of both measurements was good for the wrist cuff device ([systolic/diastolic]: r = 0.94/0.92; P < .01) and the mercury manometer (r = 0.97/0.88; P < .01). Both methods overestimated high diastolic values, whereas only the wrist cuff underestimated high systolic values. Thus, the new oscillometric wrist cuff blood pressure measurement device measures arterial blood pressure with great accuracy and reproducibility. As compared with intraarterial values, the wrist cuff device overestimated high diastolic and underestimated high systolic blood pressure values. Blood pressure values as measured by the mercury manometer were higher than intraarterial values and those of the wrist cuff. Both noninvasive devices overestimated high diastolic values.
Blood Pressure Determination↗
The use of a pressure manometer enhances student physiotherapists' performance during manual hyperinflation.
The purpose of this study was to determine the effect of using a pressure manometer on the delivery of target airway pressures during manual hyperinflation by student physiotherapists in the laboratory and clinical environments. Manual hyperinflations were delivered under control and feedback conditions where the feedback condition involved manual hyperinflation with a pressure manometer. Compared with control conditions, the availability of a manometer significantly decreased the mean absolute error (9.5 +/- 0.9 cm H2O to 1.4 +/- 0.2 cm H2O) and mean variable error (2.2 +/- 0.3 cm H2O to 1.3 +/- 0.1cm H2O) of peak airway pressures during manual hyperinflation. In addition, the availability of a manometer negated the influence of environment on accuracy. Therefore, the availability of a pressure manometer provided an effective clinical tool that was easily used to provide feedback regarding the peak airway pressures delivered during manual hyperinflation.
Adult↗
The effect of a manometer on the mean airway pressure during hand ventilation, an in vitro study.
The effect of an on-line manometer on the variables of ventilation i.e. peak inspiratory pressure (PIP), mean airway pressure (MAP), positive end expiratory pressure (PEEP), and inspiratory to expiratory time ratio (I:E) was studied in vitro. Analysis of PIP, MAP, PEEP, and I:E was made during hand ventilation of a resuscitation mannequin at the preselected PIP of 15 and 25 cm water with and without a manometer. Use of the manometer decreased the range of variation in PIP, but the MAP was higher. This was due to an increased I:E while PEEP remained unchanged. An on-line manometer during hand ventilation prevents excessive PIP but may increase the MAP and therefore may not prevent development of a pneumothorax.
Air Pressure↗
Frequency response evaluation of radial artery catheter-manometer systems: sinusoidal frequency analysis versus flush method.
It is well recognized that catheter-manometer systems significantly distort direct radial artery pressure measurements. Sinusoidal frequency analysis and the flush method of assessing the degree of distortion caused by the monitoring system were compared to determine whether these two methods agree in the estimation of natural frequency and damping coefficient. The frequency response of 30 radial artery catheter-manometer systems used for intensive-care unit patients was measured by the flush method and sinusoidal frequency analysis. The monitoring system consisted of a 20-gauge cannula, 150-cm pressure tubing, two plastic stopcocks, a continuous infusion device with fast flush valve, an American Edwards dome, a Hewlett-Packard quartz transducer, and a Hewlett-Packard blood pressure amplifier. Sinusoidal frequency analysis demonstrated second-order underdamped response for all 30 catheter-manometer systems. No secondary resonance peaks were observed up to a frequency of 200 Hz. The measured frequency response demonstrated that the average catheter-manometer system in use in our intensive care unit would cause significant distortion of the radial artery pressure, with the mean natural frequency (fn) of 14.7 +/- 3.7 Hz and the mean damping coefficient (zeta) of 0.24 +/- 0.07. Although the 30 monitoring systems had identical configurations and visible bubbles were carefully removed, a wide range of frequency responses was found (fn = 10.2 to 25.3; zeta = 0.15 to 0.44).(ABSTRACT TRUNCATED AT 250 WORDS)
Arm↗
Double tourniquet with linked mercury manometers for hand surgery.
Double tourniquets linked to separate Freon cannisters and two mercury manometers have been effective in maintaining ischemia in over 1,000 consecutive hand surgery operations. The mercury manometers permit constant accurate monitoring of the tourniquet pressure. The cuffs are used alternately. Each is inflated for up to 1 hour in order to limit the duration of nerve compression deep to the cuff. If there is malfunction of either cuff, the other cuff may be inflated at once. This system has permitted sustained ischemia in the upper extremity for up to 3 1/2 hours at a constant tourniquet pressure with no permanent clinically apparent sequellae. There has been no permanent nerve injury, although patients with more than 2 hours of tourniquet time often note hypoesthesia or paresthesia for 1 or 2 days. The alternating double tourniquet linked to a mercury manometer permits up to 3 1/2 hours of continuous ischemia of the upper limb with little risk of nerve damage.
Hand↗
The fast flush test: evaluation in radial artery catheter-manometer systems.
The 'fast flush test' is commonly used to determine the dynamic response of catheter-manometer systems in vivo. We compared the fast flush test with an established bench top test in vitro. The results of the two tests were compared in fifteen underdamped radical artery catheter-manometer systems. There were significant differences between the results, (P less than 0.001 for both resonant frequency and damping factor), and the variance of estimates within measurement systems was significantly greater in the case of the fast flush test (P less than 0.05 and P less than 0.005 for resonant frequency and damping factor respectively). Nevertheless, the differences between the tests were small by comparison with the errors associated with either test; in addition there was a significant linear correlation between the results of the two tests (r = 0.91, P less than 0.001 and r = 0.85, P less than 0.001 for resonant frequency and damping factor respectively). In the in vitro situation, therefore, the fast flush test provides a crude estimate of the dynamic parameters of underdamped catheter-manometer systems.
Arteries↗
[Evaluation of accuracy comparing three types of urological manometers (author's transl)].
Manometrical examinations of the female urinary bladder are important in the field of urodynamic diagnosis. Accuracy in these measurements is a prerequisite for the reproducibility of the results. In this study, three types of urological manometers, differing in their principles of measurement, were tested for their physical and technical properties. Pressure was measured with a membrane manometer (instrument A) with Statham elements (instrument B), and with a micro-transducer (instrument C). The results using Statham elements and micro-transducers were exactly reproducible and varied only in their interference with external factors, which affect the quality of the results in clinical routine. Concerning the physical technique of measurement, instrument C with micro-transducers gives the most accurate results and is the easiest one to manage. For research and clinical routine it is superior to instrument B. It supplies reproducible data which are independent of external parameters such as the patient's position, attention and the way the instrument is set up. Our results only urodynamical measurements using micro-transducers can be taken as absolute measurements of excellent accuracy and are comparable among themselves as well as with other absolute measurements for long-term series of measurement. Using a membrane manometer (instrument A), measurements were hardly reproducible so that these results can be accepted as orienting data only.
Evaluation Studies as Topic↗
[Reliability of blood pressure measurements; comparison of an electronic meter and a mercury manometer in family practice].
The Riva-Rocci indirect method of measuring the blood pressure carries a number of sources of error. A report is presented of a study of the serviceability of an electronic blood pressure meter as compared with the conventional mercury manometer. Seventy-six paired measurements were carried out in patients selected at random using an electronic blood pressure meter and a mercury manometer meeting all Health Council requirements. The systematic error and the incidental error in both measuring procedures were compared. The differences found were so slight as to be negligible in practice. It is concluded that the electronic blood pressure meter in practice constitutes an acceptable substitute for the conventional mercury manometer.
Blood Pressure Determination↗
Evaluation of manometer use in manual ventilation of infants in neonatal intensive care units.
Variations exist in the techniques used to perform manual ventilation in neonates and in the proficiency levels of nurses in neonatal intensive care units (NICU) who perform the procedure. This study was undertaken to determine (1) whether significant differences exist in nurses' ability to control prescribed peak inspiratory pressure (PIP) accurately when mamometers are used, as compared with when they are not used, during manual ventilation in NICU infants; and (2) whether the number of years of work experience nurses have in the NICU is related to manometer use and success in controlling prescribed PIP. The sample included 60 professional nurses whose experience ranged from 1 to 26 years. A statistically significant difference was found in nurses' ability to control PIP successfully when manometers were used as compared with when they were not used (t = 12.04, p = 0.001). Nurses with more experience tended to rely less on manometers to guide their manual ventilation techniques, but were also less accurate in controlling the delivery of PIP without the devices. We provide recommendations for clinical practice based on these findings.
Educational Status↗
Comparison of the Omron HEM-713C automated blood pressure monitor with a standard ausculatory method using a mercury manometer.
OBJECTIVES: To compare the Omron HEM-713C automated blood pressure machine with the standard ausculatory method using a mercury manometer. DESIGN: Blood pressures of randomly selected subjects were measured using both the Omron HEM-713C and the mercury manometer. SETTING: Dombotombo surburb in Marondera, Zimbabwe. SUBJECTS: One hundred and sixteen subjects 25 years and above (47 males and 69 females) randomly selected in Marondera. MAIN OUTCOME MEASURE: Systolic blood pressure and diastolic blood pressure. RESULTS: The Omron HEM-713C passed with a grade B for both systolic and diastolic blood pressures when using the British Hypertension Society protocol. It also passed both systolic and diastolic criteria for Association of the Advancement of Medical Instrumentation. CONCLUSION: The Omron HEM-713C compares well with the standard mercury manometer, we therefore recommend its use in both research and clinical applications which require blood pressure measurements.
Auscultation↗
[Recording of ventricular pressure by conventional catheter manometer systems. I. Minimal requirements of blood pressure recording systems and estimation of frequency response characteristics].
Parallel recordings of pressure pulses by conventional catheter manometer systems and catheter tip manometer demonstrate severe errors in the peak velocity of pressure rise estimated by conventional systems. This fact is due to inadequate dynamic response characteristics of conventional systems in relation to the frequency content of pressure curves. During cardiac rest the error in dp/dt max is less than 10% if the frequency response of the recording system is uniform up to 10 Hz, the corresponding value under maximal cardiac stimulation is about 40 Hz. This is equal to the first 10 harmonics of heart rate. The examination of left and right ventricular pressure curves leads to similar results. The experimental determination of dynamic response characteristics of cathermanometer systems requires a test system producing suitable sinus or step functions, parallel high fidelity recording of pressure functions to be recommended. A simple test station is described. Examinations of temperature influence on catheter material and resulting changes in dynamic response characteristics were carried out. The incubation of catheters at the temperature of 37 degrees C is indispensable. A new diagram for simplifying the interpretation of results is described. Other publications are discussed in viewpoint of employed techniques and representation of results.
Blood Pressure Determination↗
[Recording of ventricular pressure by conventional catheter manometer systems. Efficiency of several combinations of conventional catheters, modern transducers and catheter-flush systems (author's transl)].
The experimentally in vitro determined dynamic response characteristics of 38 catheter manometer systems were uniform in the worst case to 5 c.p.s. and optimally to 26 c.p.s. Accordingly, some systems are only satisfactory for ordinary pressure recording in cardiac rest, while better systems record dp/dt correct up to moderate inotropic stimulation of the heart. In the frequency range of uniform response (amplitude error less +/- 5%) the phase distortion is also negligible. In clinical application the investigator is often restricted to special type of cardiac catheter. In this case a low compliant transducer yields superior results. In all examined systems the combination with MSD 10 transducers is best, whereas the combination with P 23 Db transducers leads to minimal results. An inadequate system for recording ventricular pressure pulses leads in most cases to overestimations of dp/dtmax. The use of low frequency pass filters to attenuate higher frequency artefacts is, under clinical conditions, not suitable for extending the range of uniform frequency response. The dynamic response of 14 catheter manometer systems with two types of continuous self flush units was determined. The use of the P 37 flush unit in combination with small internal diameter catheters leads to serious error in ordinary pressure recording, due to amplitude distortion of the lower harmonics. The frequency response characteristics of the combination of an Intraflow flush system and MSD 10 transducer was similar to the non-flushing P 23 Db transducer feature.
Blood Pressure Determination↗