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Pressure Monitoring of Intraneural an Perineural Injections Into the Median, Radial, and Ulnar Nerves; Lessons From a Cadaveric Study.

Krol A, Szarko M, Vala A, De Andres J - Anesth Pain Med (2015)

Bottom Line: Intraneural needle placement produced significantly greater pressures than perineural injections did.Obtained results demonstrate significant differences between intraneural and perineural injection pressures in the median, ulnar, and radial nerves.Intraneural injection pressures show low specificity but high sensitivity suggesting that pressure monitoring might be a valuable tool in improving the safety and efficacy of peripheral nerve blockade in regional anesthesia.

View Article: PubMed Central - PubMed

Affiliation: Department of Anaesthesia and Chronic Pain Service, St Georges Hospital, London, United Kingdom.

ABSTRACT

Background: Nerve damage after regional anesthesia has been of great concern to anesthetists. Various modalities have been suggested to recognize and prevent its incidence. An understudied area is the measurement of intraneural pressure during peripheral nerve blockade. Previous investigations have produced contradicting results with only one study being conducted on human cadavers.

Objectives: The purpose of this investigation was to systematically record intraneural and perineural injection pressures on the median, ulnar, and radial nerves exclusively as a primary outcome.

Materials and methods: Ultrasonography-guided injections of 1 mL of 0.9% NaCl over ten seconds were performed on phenol glycerine embalmed cadaveric median, ulnar, and radial nerves. A total of 60 injections were performed, 30 intraneural and 30 perineural injections. The injections pressure was measured using a controlled disc stimulation device. Anatomic dissection was used to confirm needle placement.

Results: Intraneural needle placement produced significantly greater pressures than perineural injections did. The mean generated pressures in median, radial, and ulnar nerves were respectively 29.4 ± 9.3, 27.3 ± 8.5, and 17.9 ± 7.0 pound per square inch (psi) (1 psi = 51.7 mmHg) for the intraneural injections and respectively 7.2 ± 2.5, 8.3 ± 2.5, and 6.7 ± 1.8 psi for perineural injections. Additionally the intraneural injection pressures of the ulnar nerve were lower than those of the median and radial nerves.

Conclusions: Obtained results demonstrate significant differences between intraneural and perineural injection pressures in the median, ulnar, and radial nerves. Intraneural injection pressures show low specificity but high sensitivity suggesting that pressure monitoring might be a valuable tool in improving the safety and efficacy of peripheral nerve blockade in regional anesthesia. Peripheral nerves "pressure mapping" hypothetically might show difference amongst various nerves depending on anatomic location, histologic structure, and ultrasonographic appearance.

No MeSH data available.


Related in: MedlinePlus

Illustrating the ultrasonography-guided needle placement (2A and 2B, perineural and intraneural injections, respectively) and the corresponding dissections to confirm the need position (2C and 2D, perineural and intraneural injections, respectively)
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fig17955: Illustrating the ultrasonography-guided needle placement (2A and 2B, perineural and intraneural injections, respectively) and the corresponding dissections to confirm the need position (2C and 2D, perineural and intraneural injections, respectively)

Mentions: We defined opening injection pressure as the pressure peak that followed the initiation of the injection. Most of the injections produced a similar pattern of a low initial pressure, increasing to a maximal “peak pressure” (opening injection pressure) and ended in a lower pressure. Some injections did not reach peak value within ten-second injection time. The CDS device was utilized as it is known to deliver precise pressure recordings in provocative discography: volume accuracy of 0.05 mL, pressure accuracy of ± 5%, and flow rate accuracy of 1.1% as per Operation/Service Manual (19). The NeuroTherm CDS system employs a syringe pump that delivers media in a controlled fashion, a syringe with an integrated pressure transducer, and a piece of software that allows the calculation of the pressure at the tip of the needle by accounting for the fluid dynamic variables between the transducer and the tip of the needle. The calculated pressure is displayed on the CDS screen. Data was recorded using a computer-based data acquisition system (LabView, USA). In this study, encountered fluid dynamics were described using the Navier-Stokes equation, which took the key variables affecting fluid behavior into account. The key variables were fluid viscosity (cP), flow rate (mL/s), needle length (cm), needle gauge (ga), tubing length, and tubing diameter. To detect any difference in terms of needle length, we measured the baseline (needle open to air) pressure of injection of 1 mL of 0.9% NaCl at a rate of 1 mL in ten seconds with 22-G needles of consecutively 100-mm, 80-mm, and 50-mm lengths as these needle lengths are routinely used clinically. The tubing length was kept the same in each case. The present investigation chose the 80-mm needle as it was most commonly used in clinical practice in our institution. Peripheral nerve block of median, ulnar, and radial nerve, selectively or in combination, often follows immediately infraclavicular brachial plexus block to speed up onset in desired distribution. Needles were left in situ after completing the injection and recording of injection pressure. The cadavers were subsequently dissected to confirm needle placement. The dissections confirmed needle placement and are illustrated together with the USG images in Figure 2. All injections were performed by main investigator (AK) with more than eight years of experience in USG-guided interventions. Injection pressures were recorded on CDS device by DD (David Drew - Operator of CDS device (AK) being blinded to the needle position. All dissections were performed by MS and AV. The data was statistically analyzed using paired-samples t tests to compare the intraneural and perineural values obtained from the same nerves. Significance was assumed at P < 0.05. All statistical analyses were conducted using GraphPad (version 6, USA).


Pressure Monitoring of Intraneural an Perineural Injections Into the Median, Radial, and Ulnar Nerves; Lessons From a Cadaveric Study.

Krol A, Szarko M, Vala A, De Andres J - Anesth Pain Med (2015)

Illustrating the ultrasonography-guided needle placement (2A and 2B, perineural and intraneural injections, respectively) and the corresponding dissections to confirm the need position (2C and 2D, perineural and intraneural injections, respectively)
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493739&req=5

fig17955: Illustrating the ultrasonography-guided needle placement (2A and 2B, perineural and intraneural injections, respectively) and the corresponding dissections to confirm the need position (2C and 2D, perineural and intraneural injections, respectively)
Mentions: We defined opening injection pressure as the pressure peak that followed the initiation of the injection. Most of the injections produced a similar pattern of a low initial pressure, increasing to a maximal “peak pressure” (opening injection pressure) and ended in a lower pressure. Some injections did not reach peak value within ten-second injection time. The CDS device was utilized as it is known to deliver precise pressure recordings in provocative discography: volume accuracy of 0.05 mL, pressure accuracy of ± 5%, and flow rate accuracy of 1.1% as per Operation/Service Manual (19). The NeuroTherm CDS system employs a syringe pump that delivers media in a controlled fashion, a syringe with an integrated pressure transducer, and a piece of software that allows the calculation of the pressure at the tip of the needle by accounting for the fluid dynamic variables between the transducer and the tip of the needle. The calculated pressure is displayed on the CDS screen. Data was recorded using a computer-based data acquisition system (LabView, USA). In this study, encountered fluid dynamics were described using the Navier-Stokes equation, which took the key variables affecting fluid behavior into account. The key variables were fluid viscosity (cP), flow rate (mL/s), needle length (cm), needle gauge (ga), tubing length, and tubing diameter. To detect any difference in terms of needle length, we measured the baseline (needle open to air) pressure of injection of 1 mL of 0.9% NaCl at a rate of 1 mL in ten seconds with 22-G needles of consecutively 100-mm, 80-mm, and 50-mm lengths as these needle lengths are routinely used clinically. The tubing length was kept the same in each case. The present investigation chose the 80-mm needle as it was most commonly used in clinical practice in our institution. Peripheral nerve block of median, ulnar, and radial nerve, selectively or in combination, often follows immediately infraclavicular brachial plexus block to speed up onset in desired distribution. Needles were left in situ after completing the injection and recording of injection pressure. The cadavers were subsequently dissected to confirm needle placement. The dissections confirmed needle placement and are illustrated together with the USG images in Figure 2. All injections were performed by main investigator (AK) with more than eight years of experience in USG-guided interventions. Injection pressures were recorded on CDS device by DD (David Drew - Operator of CDS device (AK) being blinded to the needle position. All dissections were performed by MS and AV. The data was statistically analyzed using paired-samples t tests to compare the intraneural and perineural values obtained from the same nerves. Significance was assumed at P < 0.05. All statistical analyses were conducted using GraphPad (version 6, USA).

Bottom Line: Intraneural needle placement produced significantly greater pressures than perineural injections did.Obtained results demonstrate significant differences between intraneural and perineural injection pressures in the median, ulnar, and radial nerves.Intraneural injection pressures show low specificity but high sensitivity suggesting that pressure monitoring might be a valuable tool in improving the safety and efficacy of peripheral nerve blockade in regional anesthesia.

View Article: PubMed Central - PubMed

Affiliation: Department of Anaesthesia and Chronic Pain Service, St Georges Hospital, London, United Kingdom.

ABSTRACT

Background: Nerve damage after regional anesthesia has been of great concern to anesthetists. Various modalities have been suggested to recognize and prevent its incidence. An understudied area is the measurement of intraneural pressure during peripheral nerve blockade. Previous investigations have produced contradicting results with only one study being conducted on human cadavers.

Objectives: The purpose of this investigation was to systematically record intraneural and perineural injection pressures on the median, ulnar, and radial nerves exclusively as a primary outcome.

Materials and methods: Ultrasonography-guided injections of 1 mL of 0.9% NaCl over ten seconds were performed on phenol glycerine embalmed cadaveric median, ulnar, and radial nerves. A total of 60 injections were performed, 30 intraneural and 30 perineural injections. The injections pressure was measured using a controlled disc stimulation device. Anatomic dissection was used to confirm needle placement.

Results: Intraneural needle placement produced significantly greater pressures than perineural injections did. The mean generated pressures in median, radial, and ulnar nerves were respectively 29.4 ± 9.3, 27.3 ± 8.5, and 17.9 ± 7.0 pound per square inch (psi) (1 psi = 51.7 mmHg) for the intraneural injections and respectively 7.2 ± 2.5, 8.3 ± 2.5, and 6.7 ± 1.8 psi for perineural injections. Additionally the intraneural injection pressures of the ulnar nerve were lower than those of the median and radial nerves.

Conclusions: Obtained results demonstrate significant differences between intraneural and perineural injection pressures in the median, ulnar, and radial nerves. Intraneural injection pressures show low specificity but high sensitivity suggesting that pressure monitoring might be a valuable tool in improving the safety and efficacy of peripheral nerve blockade in regional anesthesia. Peripheral nerves "pressure mapping" hypothetically might show difference amongst various nerves depending on anatomic location, histologic structure, and ultrasonographic appearance.

No MeSH data available.


Related in: MedlinePlus