An Animal Model of "Syringe Feel" During Peripheral Nerve Block

Theron, P; Mackay, Zahoor; Gonzalez, J.G.; Donaldson, Nora; Blanco, Rafael

doi:10.1097/aap.0b013e3181ac7f38

Cited by 27 publications

(14 citation statements)

References 11 publications

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“…Subjective sensation, as may be expected, is not reliable [7,8] and further confounded by the size and design of the syringe. Instrumental measurement or limitation of injection pressures may be more reliable and devices have been marketed for this purpose.…”

Section: Introductionmentioning

confidence: 93%

“…The ''opening'' pressure makes the physical characteristics of the regional anesthesia needle and circuit irrelevant as pressure is uniformly transmitted through the communicating system at zero flow. This, combined with the unreliability of subjective sensation [7,8], is the rationale behind the development of objective regional anesthesia pressure monitors. However, there is currently insufficient clinical experience with injection pressure monitoring to assess its impact on patient outcomes [10].…”

Section: Indicators Of Intraneural Injectionmentioning

confidence: 99%

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An improvised pressure gauge for regional nerve blockade/anesthesia injections: an initial study

Patil

Ankireddy

Wilkes³

et al. 2015

J Clin Monit Comput

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High injection pressure is one of the warning signs of intraneural injection, with animal models suggesting pressures higher than 69 or 176 kPa as high risk, and is normally detected subjectively and inaccurately. We describe a system improvised from common clinical components that uses Boyle's law to objectively measure injection pressure. The objectives of the study were to (1) Validate our improvised pressure gauge (IPG) by comparing the injection pressure as calculated by Boyle's law against the measured pressure and (2) Use the IPG to measure the range of injection pressures by two groups of anesthetic professionals using the "syringe feel" technique. Our IPG system consists of an extended 1 ml syringe attached to a 3-way stopcock, inserted between the syringe containing the local anesthetic injectate and the needle. The IPG was validated against a pressure calibration reference. 20 anesthesiologists and 20 anesthetic assistants were recruited to apply pressure to the 20 ml syringe in vitro while blinded to the attached IPG. The pressures were measured on three separate occasions for each participant. There was good agreement (<8 percent difference) between the measured and theoretical pressure values. Anesthesiologists exceeded the threshold of 69 kPa in 18 of a total of 60 attempts whereas anesthetic assistants exceeded the threshold in 30 attempts out of 60 attempts. Anesthetic assistants exerted a higher overall pressure of 80 kPa compared to 51 kPa for anesthesiologists-this was statistically significant (p = 0.027). Our improvised system is easily and rapidly assembled from common clinical equipment and shows promise as a monitor for inadvertent intraneural injection.

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Section: Introductionmentioning

confidence: 93%

Section: Indicators Of Intraneural Injectionmentioning

confidence: 99%

An improvised pressure gauge for regional nerve blockade/anesthesia injections: an initial study

Patil

Ankireddy

Wilkes³

et al. 2015

J Clin Monit Comput

View full text Add to dashboard Cite

show abstract

“…'syringe feel' and a variety of variable pressure valves and improvised devices. The subjective 'syringe feel' has been found to be unreliable even in experienced hands and is easily confounded by syringe size [8,9]. Pressures required to achieve hydrodissection of a nerve in a number of tissues (muscle, fascia) have not been investigated, but may be similarly high initially until a space is created for local anaesthetic to spread.…”

Section: Discussionmentioning

confidence: 99%

“…In clinical practice, injection pressures are commonly estimated by the force exerted on the syringe plunger, however, this technique has been shown to be subjective and unreliable [8,9]. A better understanding of the individual components upstream from the needle tip is currently lacking and may be useful to inform safe regional anaesthesia practice.…”

Section: Introductionmentioning

confidence: 99%

The effect of needle dimensions and infusion rates on injection pressures in regional anaesthesia needles: a bench-top study

et al. 2014

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SummaryAnimal studies have shown that injection pressures > 75 kPa indicate probable intrafascicular needle tip position. This study describes the flow/pressure characteristics of seven common needle systems. A syringe pump delivered flow rates of 5, 6.67, 10, 13.3, 15 and 20 ml.min À1 through these needle systems, while keeping the needle tips open to atmosphere. A pressure transducer connected between the syringe and needle provided a real-time graphical display for analysis. Mean plateau pressures increased linearly with flow and with decreasing needle diameter (2.7-92 kPa). Flow rates > 17 ml.min À1 and needle sizes 22 G and smaller produced mean plateau pressures > 75 kPa.Pressure monitors upstream from the needle may produce false-positive alarms at high flow rates due to needle resistance, and unreliable readings due to non-laminar flow. We recommend injection rates ≤ 15 ml.min À1 (0.25 ml.s À1 )to reduce the effect of factors upstream from the needle tip as a cause of high pressure readings.

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“…Furthermore, single-operator methods for detecting high injection pressures have been discredited on the grounds of subjectivity in perceived force applied to syringe plungers [5,6].…”

Section: Nerve Block Injection Pressure Monitoringmentioning

confidence: 99%

Nerve block injection pressure monitoring

Adams

2015

Anaesthesia

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An Animal Model of "Syringe Feel" During Peripheral Nerve Block

Abstract: Under the conditions of this study model, anesthetists were unable to correctly identify intraneural injection by syringe feel during simulated regional anesthesia.

Cited by 27 publications

References 11 publications

An improvised pressure gauge for regional nerve blockade/anesthesia injections: an initial study

An improvised pressure gauge for regional nerve blockade/anesthesia injections: an initial study

The effect of needle dimensions and infusion rates on injection pressures in regional anaesthesia needles: a bench-top study

Nerve block injection pressure monitoring

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