Review Article
Open Access
Noninvasive Acoustic Respiration Rate Monitoring
Kentaro Ouchi*
Department of Dental Anesthesiology, Field of Maxillofacial Diagnostic and Surgical Sciences
Faculty of Dental Science, Kyushu University Graduate School, Japan
Faculty of Dental Science, Kyushu University Graduate School, Japan
*Corresponding author: Kentaro Ouchi, Department of Dental Anesthesiology, Field of Maxillofacial Diagnostic and Surgical Sciences, Faculty
of Dental Science, Kyushu University Graduate School, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan, Tel: +81-92-641-1151; Fax: +81-92-
642-6481; E-mail:
@
Received: February 23, 2016; Accepted: April 12, 2016, Published: May 24, 2016
Citation: Ouchi K (2016) Noninvasive Acoustic Respiration Rate Monitoring. SOJ Anesthesiol Pain Manag. 3(1): 1-3. DOI: http://dx.doi.org/10.15226/2374-684X/3/1/00131
Abstract Top
A new acoustic method for Respiratory Rate Monitoring (RRa®)
has shown good reliability when used in patients without tracheal
intubation. The objective of this review is to assess the usefulness
of acoustic respiratory rate monitoring. In contrast to facemask
capnometry, the acoustic monitor was well tolerated; contrary,
capnometry was not well tolerated, because several patients removed
the facemask. In intravenous general anesthesia, the acoustic
monitor is useful for continuous monitoring of respiratory rate in
spontaneously breathing patients. In pediatric patients, acoustic
monitor showed good agreement and similar accuracy and precision
between capnometry but was better tolerated.
In conclusion, the acoustic respiratory monitoring is useful for non-intubated patients.
In conclusion, the acoustic respiratory monitoring is useful for non-intubated patients.
Introduction
Several respiratory rate monitoring techniques are available.
A new acoustic method for respiratory rate monitoring (RRa®,
Masimo Corp.) has shown good reliability when used in patients
without tracheal intubation in dental operating room [1], postanesthesia
care units [2,3], intensive care units [4], and emergency
units [5]. Because there is no 'gold standard' for measurement of
respiration rate, these reports were compared acoustic monitor
with widely used methods (capnography or thoracic impedance
pneumography). One such technique, capnography, is often used
because of its ability to detect cessation of breathing before there
is a decrease in pulse oxygen saturation. Capnography requires
the use of a sampling line connected to an oral or nasal mask, and
since the facemask for capnometry was removed many times, its
use is limited [5]. We systematically searched Medline via PubMed
using the keywords "acoustic respiratory rate monitoring". The
electronic search was performed in January 2016. The publicized
period was limited in 2012 or later. Case reports and original
article irrelevant to RRa® were excluded.
The objective of this review is to assess the usefulness of acoustic respiratory rate monitoring. And, I have reviewed these reports in order to give some general recommendations.
The objective of this review is to assess the usefulness of acoustic respiratory rate monitoring. And, I have reviewed these reports in order to give some general recommendations.
System of device
A non-invasive respiratory monitoring device, using
an adhesive sensor with an integrated acoustic transducer
positioned on the patient's throat, has been recently introduced.
This device analyses respiratory vibrations to detect inspiratory
and expiratory flow. The sensor has been united with adhesive
tape and acoustic transducer, in manufacture (Figure 1).
Acoustic sensor was placed on the patient's throat, on the side
of the larynx and above the thyroid cartilage. And acoustic
sensor was connected to a specific device (Radical-7® Pulse
Oximeter, Masimo Corp.). The acoustic signal is then converted
to continuous, numeric values of respiration rate.
The sensor allows real time analysis of the vibrations
emanating from the patient's larynx and enables isolation of the
respiratory sounds via analysis of the trace obtained through
various filters. In this mechanism, the device seems to refer to the
information from the pulse oximetry of the finger. The noise is
removed by collating it with breathing pattern information from
the pulse oximetry. However, the details of the mechanism are
veiled in trade secrets. The acoustic signal is then converted to a
numerical value, allowing a continuous display of the respiratory
rate (/min).
Figure 1:
The use under various situations
For post-anesthesia care
Previous study reported that adult patients admitted to the
post-anesthesia care unit (PACU) after extubation after general
anesthesia were studied [2]. In this report, 42 patients with age
of mean 54 years were enrolled. It is reported that continuous
assessment of respiration rate with an acoustic monitor
correlated well with capnometry. There were fewer errors of
acoustic sensor than capnometry. The acoustic monitor was well
tolerated; contrary, capnometry was not well tolerated, because
eight patients removed the facemask.
Another previous study reported that adult patients admitted to PACU after extubation after general anesthesia were studied [3]. In this report, 33 patients with age of mean 45 years were enrolled. It is reported that, the acoustic monitor was statistically more accurate and more precise than the capnometry, but differences in performance were modest.
In comparison between capnography, the acoustic monitor is useful for continuous monitoring of respiratory rate in spontaneously breathing subjects for post-anesthesia care. Differences in performance were modest, unless removed the facemask.
Another previous study reported that adult patients admitted to PACU after extubation after general anesthesia were studied [3]. In this report, 33 patients with age of mean 45 years were enrolled. It is reported that, the acoustic monitor was statistically more accurate and more precise than the capnometry, but differences in performance were modest.
In comparison between capnography, the acoustic monitor is useful for continuous monitoring of respiratory rate in spontaneously breathing subjects for post-anesthesia care. Differences in performance were modest, unless removed the facemask.
For emergency ward
Previous study reported that adult patients admitted to
emergency ward after extubation after drug or alcoholic poisoning
were studied [5]. In this report, 30 patients with age of mean 37
years, hospitalized at the emergency department for drug or
alcoholic poisoning, were enrolled. The acoustic monitor seems
more accurate than thoracic impedance and better tolerated
than facemask capnometry. Moreover, this report reported
as follows. In adhesive tape with acoustic sensor, no allergic
phenomenon was observed during the study. The acoustic sensor
was repositioned in 3 cases, because the sensor got unstuck. The
causes were agitation in 2 cases and substantial hairiness in 1
case. The electrodes for impedance measurement repositioned
in 2 cases, because the sensor got unstuck. The facemask for
capnometry was removed many times by 11 patients, so that
emergency staff had to intervene and reposition them.
In comparison between thoracic impedance and capnography, the acoustic monitor is useful for continuous monitoring of respiratory rate in spontaneously breathing subjects for emergency ward.
In comparison between thoracic impedance and capnography, the acoustic monitor is useful for continuous monitoring of respiratory rate in spontaneously breathing subjects for emergency ward.
For general anesthesia with airway management
Under airway management such as intubation,
pneumotachograph with anesthesia machine and capnometry
are useful for respiratory monitoring. However, the study using
acoustic monitor in the operating room under general anesthesia
with a laryngeal mask airway was reported [6]. In this report,
53 patients undergoing urologic procedures in the operating
room under general anesthesia with a laryngeal mask airway,
spontaneous ventilation and no muscle relaxation, were enrolled.
Patients were monitored for respiration rate with acoustic monitor and in-circuit pneumotachograph. Instantaneous
respiratory rates were obtained from the pneumotachograph.
Acoustic monitor demonstrated a median delay of 45 seconds
to detect a 1 (/min) change in instantaneous respiratory rates.
And, acoustic monitor detects changes in respiratory rate,
demonstrates minimal bias.
In comparison between normality widely used methods under airway management (capnography and pneumotachograph), normality widely used methods is useful for continuous monitoring of respiratory rate for general anesthesia with airway management, because acoustic monitor demonstrated delay to detect change in respiratory rates.
In comparison between normality widely used methods under airway management (capnography and pneumotachograph), normality widely used methods is useful for continuous monitoring of respiratory rate for general anesthesia with airway management, because acoustic monitor demonstrated delay to detect change in respiratory rates.
For sedation for gastrointestinal endoscopy
procedures
Previous study reported that adult patients under propofolbased
sedation for upper gastrointestinal endoscopy were
studied [7]. In this report, 101 patients with age of mean 59 years
undergoing upper gastrointestinal endoscopy under sedation
without airway management such as tracheal intubation were
enrolled. Patients were monitored for respiration rate with
acoustic monitor, capnometry and impedance pneumography
and values were compared to the manual counting of breaths
by observation of chest wall movements. Acoustic monitor was
found to be accurate for assessment of respiration rate and to
have similar or better sensitivity and specificity for detection of
apnea compared to capnometry and impedance pneumography
in upper gastrointestinal endoscopy.
In comparison between thoracic impedance or capnography, the acoustic monitor is useful for detection of apnea in spontaneously breathing subjects for sedation during gastrointestinal endoscopy procedure.
In comparison between thoracic impedance or capnography, the acoustic monitor is useful for detection of apnea in spontaneously breathing subjects for sedation during gastrointestinal endoscopy procedure.
For intravenous anesthesia without tracheal
intubation
Previous study reported that adult patients with dental
anxiety undergoing dental treatment under intravenous
anesthesia without tracheal intubation were studied [1].
In this report, 11 patients with age of mean 38 years were
enrolled. Respiratory rate was recorded every 30 seconds
using the acoustic method and capnometry, and detect ability
of respiratory rate was investigated for both methods. A total
of 1953 data points of respiratory rate were obtained from the
start to end of anesthesia. The number of detected points by the
acoustic method (1884, 96.5%) was significantly higher than that
by capnometry (1682, 86.1%).
In comparison between capnometry, the acoustic monitor is useful for continuous monitoring of respiratory rate in spontaneously breathing patients undergoing dental procedures under intravenous general anesthesia.
In comparison between capnometry, the acoustic monitor is useful for continuous monitoring of respiratory rate in spontaneously breathing patients undergoing dental procedures under intravenous general anesthesia.
For children
Previous study reported that pediatric patients admitted
to PACU after extubation after general anesthesia were studied
[8]. In this report, 57 patients with age of mean 7years (range: 1.2 – 15) were enrolled. The acoustic sensor was applied to the
patient's neck according to the directions for use. Respiration
rate data were recorded from acoustic monitor and capnometry.
Patients of 97.5% demonstrated good tolerance of the acoustic
monitor, where as patients of 62.5% demonstrated good
tolerance of the capnometry. Acoustic monitor showed good
agreement and similar accuracy and precision but was better
tolerated in postsurgical pediatric patients.
In comparison between capnometry, the acoustic monitor is useful for continuous monitoring of respiratory rate in spontaneously breathing patients for postsurgical pediatric patients.
In comparison between capnometry, the acoustic monitor is useful for continuous monitoring of respiratory rate in spontaneously breathing patients for postsurgical pediatric patients.
False alarm
Previous study that the use of acoustic respiratory monitoring
in children receiving opioid infusions on a postsurgical ward was
evaluated and false alarm was assessed was reported [9].This
report indicated that, episodes of desaturation were observed
in 9 patients, but the use of acoustic respiratory monitoring did
not improve the detection of respiratory depression. And this
reported that acoustic monitor resulted in an unacceptably high
false alarm rate. Development and improvement of alarm system
may be needed.
Discussion
In comparison between capnography, the acoustic monitor
is useful for continuous monitoring of respiratory rate in
spontaneously breathing subjects. Because capnometry is not
tolerated when the sampling line was removed. It occurs when
patients removed the facemask [2, 5]. And it occurs at mouth
breathing, under respiratory monitoring by capnography coupled
with a nasal cannula [7]. In comparison between normality widely
used methods (capnography and pneumotachograph) under
airway management, normality widely used methods is useful
than acoustic monitor for continuous monitoring of respiratory
rate for general anesthesia with airway management. Because
demonstrated delay to detect change in respiratory rates [6].
Therefore the acoustic respiratory monitoring is useful for nonintubated
patients.
Conclusion
The acoustic respiratory monitoring is useful for nonintubated
patients.
ReferencesTop
- Ouchi K, Fujiwara S, Sugiyama K. Acoustic method respiratory rate monitoring is useful in patients under intravenous anesthesia. J Clin Monit Comput. 2016.
- Mimoz O, Benard T, Gaucher A, Frasca D, Debaene B. Accuracy of respiratory rate monitoring using a non-invasive acoustic method after general anaesthesia. Br J Anaesth. 2012;108(5):872-875.
- Ramsay MA, Usman M, Lagow E, Mendoza M, Untalan E, De Vol E. The accuracy, precision and reliability of measuring ventilatory rate and detecting ventilatory pause by rainbow acoustic monitoring and capnometry. Anesth Analg. 2013;117(1):69-75.doi: 10.1213/ANE.0b013e318290c798.
- Autet LM, Frasca D, Pinsard M, Cancel A, Rousseau L, Debaene B, et al. Evaluation of acoustic respiration rate monitoring after extubation in intensive care unit patients. Br J Anaesth. 2014;113(1):195-197.
- Guechi Y, Pichot A, Frasca D, Rayeh-Pelardy F, Lardeur JY, Mimoz O. Assessment of noninvasive acoustic respiration rate monitoring in patients admitted to an Emergency Department for drug or alcoholic poisoning. J Clin Monit Comput. 2015. 2015;29(6):721-726.
- Atkins JH, Mandel JE. Performance of Masimo rainbow acoustic monitoring for tracking changing respiratory rates under laryngeal mask airway general anesthesia for surgical procedures in the operating room: a prospective observational study. Anesth Analg. 2014;119(6):1307-1314.
- Goudra BG, Penugonda LC, Speck RM, Sinha JC. Comparison of acoustic respiration rate, impedance pneumography and capnometry monitors for respiration rate accuracy and apnea detection during GI endoscopy anesthesia. Open J Anesthesiol. 2013;3:74-79.
- Patino M, Redford DT, Quigley TW, Mahmoud M, Kurth CD, Szmuk P. Accuracy of acoustic respiration rate monitoring in pediatric patients. Paediatr Anaesth. 2013;23(12):1166-1673.
- Gorges M, West NC, Christopher NA, Koch JL, Brodie SM, Lowlaavar N, et al. An Ethnographic Observational Study to Evaluate and Optimize the Use of Respiratory Acoustic Monitoring in Children Receiving Postoperative Opioid Infusions. Anesth Analg. 2016;122(4):1132-1340.