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S R Montano

Publications and source records attributed to S R Montano.

4 recordsLinked to original sources
PubMed1996

The use of a load cell for continuous cardiotomy reservoir level measurement during cardiopulmonary bypass.

We have examined the use of a 6 kg strain-gauge load cell for the purpose of continuous measurement of cardiotomy reservoir volume during cardiopulmonary bypass. It performed reliably and reproducibly and was found to be simple to interface to an anaesthesia monitor. The resolution of the cell was +/- 15 ml and the bias and limits of agreement for a series of 221 measurements were +15 ml and 175 ml, respectively. A continuously available digital level signal can present significant advantages to the perfusionist. The signal can be presented remotely in the form of a bar graph or a digital display, or can be interfaced to an intelligent alarm system which can be triggered on the basis of "time to expected reservoir exhaustion' rather than absolute reservoir level. The alarm state can also be conveyed in spoken form using speech synthesis. Finally, when recorded by an automatic record keeping system, the reservoir level constitutes an important addition to the perfusion record.

Cardiac Volume↗
PubMed1996

Response times to visual and auditory alarms during anaesthesia.

OBJECTIVE: To measure and compare the response times to audibly or visually presented alarms in the operating theatre. METHODS: The time taken by anaesthetists to cancel randomly generated visual and audible false alarms was measured during maintenance of routine anaesthesia. Alarms were generated and times recorded by a laptop computer on the anaesthetic machine. The visual signal was a 15 mm diameter red light positioned next to the physiological monitor mounted on top of the machine. The audible alarm was a Sonalert buzzer of the type incorporated into many medical devices. RESULTS: Nineteen anaesthetists provided a total of seventy-two hours of data (887 alarm events). The response times to visual alarms was significantly longer than to audible alarms (P = 0.001 Mann Whitney U test). [Table: see text] CONCLUSIONS: The ability of anaesthetists to appreciate changes in patient physiology may be limited by delays in noticing information presented by monitors. The rapid response to the vast majority of alarms indicates a high level of vigilance among the anaesthetists studied. However, this study suggests that it is safer to rely on audible rather than visual alarms when time-critical information such as oxygenation, heart beat and ventilator disconnection is concerned. Visual alarms would appear to be more appropriate for conveying less urgent information.

Anesthesiology↗
PubMed1991

Physics and function of operating room suction.

A study was done to evaluate the performance of suction apparatus in the operating room. The investigation was prompted by perceived poor suction performance in a suite of new operating rooms built in accordance with Standards Australia (SA) specifications. SA performance tests were conducted on each of four suction outlets in nine operating rooms. All 36 outlets complied with SA standards for flow-rate (minimum 40 L/min) and occluded negative pressure (ONP; minimum -60 kPa). However, 24 collection units failed to comply with standards (ONP) of -40 kPa achieved in less than 4 s when a 4 L disposable suction apparatus was connected (mean time to ONP: 6.1 s, 95% confidence interval: 4.9, 7.3). When smaller capacity suction jars were substituted, more units met SA standards. The standards therefore need revision to include specification of the capacity of the collecting apparatus. Other factors that were found to degrade suction performance significantly were air leakage and defective shut-off valves. The physical principles involved in operating room suction are described. Surgeons and anaesthetists should understand these principles, and it is recommended that a simple pre-operative check of the suction apparatus should be carried out, as follows: (1) Turn the wall control knob fully on, and disconnect the suction apparatus. The gauge should register zero. (2) Connect the suction jars. If the indicated gauge pressure is in excess of -15 kPa, investigate the equipment for excessive resistance, particularly in the shut-off valve, which should be replaced with a new unit if necessary.(ABSTRACT TRUNCATED AT 250 WORDS)

Australia↗