A Novel Auditory Display for Neonatal Resuscitation: Laboratory Studies Simulating Pulse Oximetry in the First 10 Minutes After Birth

Enhanced Neonatal Pulse Oximetry Sounds for the First Minutes of Life: A Laboratory Trial

OBJECTIVE

Auditory enhancements to the pulse oximetry tone may help clinicians detect deviations from target ranges for oxygen saturation (SpO2) and heart rate (HR).

BACKGROUND

Clinical guidelines recommend target ranges for SpO2 and HR during neonatal resuscitation in the first 10 minutes after birth. The pulse oximeter currently maps HR to tone rate, and SpO2 to tone pitch. However, deviations from target ranges for SpO2 and HR are not easy to detect.

METHOD

Forty-one participants were presented with 30-second simulated scenarios of an infant's SpO2 and HR levels in the first minutes after birth. Tremolo marked distinct HR ranges and formants marked distinct SpO2 ranges. Participants were randomly allocated to conditions: (a) No Enhancement control, (b) Enhanced HR Only, (c) Enhanced SpO2 Only, and (d) Enhanced Both.

RESULTS

Participants in the Enhanced HR Only and Enhanced SpO2 Only conditions identified HR and SpO2 ranges, respectively, more accurately than participants in the No Enhancement condition, ps < 0.001. In the Enhanced Both condition, the tremolo enhancement of HR did not affect participants' ability to identify SpO2 range, but the formants enhancement of SpO2 may have attenuated participants' ability to identify tremolo-enhanced HR range.

CONCLUSION

Tremolo and formant enhancements improve range identification for HR and SpO2, respectively, and could improve clinicians' ability to identify SpO2 and HR ranges in the first minutes after birth.

APPLICATION

Enhancements to the pulse oximeter tone to indicate clinically important ranges could improve the management of oxygen delivery to the neonate during resuscitation in the first 10 minutes after birth.

Effects of multitasking on interpreting a spearcon sequence display for monitoring multiple patients

Spearcons are time-compressed speech phrases. When arranged in a sequence representing vital signs of multiple patients, spearcons may be more informative than conventional auditory alarms. However, multiple resource theory suggests that certain timeshared tasks might interfere with listeners' ability to understand spearcons. We tested the relative interference with spearcon identification from the following ongoing tasks: (1) manual tracking, (2) linguistic detection of spoken target words, (3) arithmetic true-false judgments, or (4) an ignored background speech control. Participants were 80 non-clinicians. The linguistic task worsened spearcon identification more than the tracking task, p < .001, and more than ignored background speech, p = .012. The arithmetic task worsened spearcon identification more than the tracking task, p < .001. The linguistic task and arithmetic task both worsened performance, p = .674. However, no ongoing task affected participants' ability to detect which patient(s) in a sequence had abnormal vital signs. Future research could investigate whether timeshared tasks affect non-speech auditory alerts.

Evaluating enhanced pulse oximetry auditory displays for neonatal oxygen targeting: A randomized laboratory trial with clinicians and non-clinicians

Standard pulse oximeter auditory tones do not clearly indicate departures from the target range of oxygen saturation (SpO₂) of 90%-95% in preterm neonates. We tested whether acoustically enhanced tones would improve participants' ability to identify SpO₂ range. Twenty-one clinicians and 23 non-clinicians used (1) standard pulse oximetry variable-pitch tones plus alarms; (2) beacon-enhanced tones without alarms in which reference tones were inserted before standard pulse tones when SpO₂ was outside target range; and (3) tremolo-enhanced tones without alarms in which pulse tones were modified with tremolo when SpO₂ was outside target range. For clinicians, range identification accuracies (mean (SD)) in the standard, beacon, and tremolo conditions were 52% (16%), 73% (14%) and 76% (13%) respectively, and for non-clinicians 49% (16%), 76% (13%) and 72% (14%) respectively, with enhanced conditions always significantly more accurate than standard. Acoustic enhancements to pulse oximetry clearly indicate departures from preterm neonates' target SpO₂ range.

Signaling Patient Oxygen Desaturation with Enhanced Pulse Oximetry Tones

Manufacturers could improve the pulse tones emitted by pulse oximeters to support more accurate identification of a patient's peripheral oxygen saturation (SpO2) range. In this article, we outline the strengths and limitations of the variable-pitch tone that represents SpO2 of each detected pulse, and we argue that enhancements to the tone to demarcate clinically relevant ranges are feasible and desirable. The variable-pitch tone is an appreciated and trusted feature of the pulse oximeter's user interface. However, studies show that it supports relative judgments of SpO2 trends over time and is less effective at supporting absolute judgments about the SpO2 number or conveying when SpO2 moves into clinically important ranges. We outline recent studies that tested whether acoustic enhancements to the current tone could convey clinically important ranges more directly, without necessarily using auditory alarms. The studies cover the use of enhanced variable-pitch pulse oximeter tones for neonatal and adult use. Compared with current tones, the characteristics of the enhanced tones represent improvements that are both clinically relevant and statistically significant. We outline the benefits of enhanced tones, as well as discuss constraints of which developers of enhanced tones should be aware if enhancements are to be successful.

Signaling Patient Oxygen Desaturation with Enhanced Pulse Oximetry Tones

Manufacturers could improve the pulse tones emitted by pulse oximeters to support more accurate identification of a patient's peripheral oxygen saturation (SpO2) range. In this article, we outline the strengths and limitations of the variable-pitch tone that represents SpO2 of each detected pulse, and we argue that enhancements to the tone to demarcate clinically relevant ranges are feasible and desirable. The variable-pitch tone is an appreciated and trusted feature of the pulse oximeter's user interface. However, studies show that it supports relative judgments of SpO2 trends over time and is less effective at supporting absolute judgments about the SpO2 number or conveying when SpO2 moves into clinically important ranges. We outline recent studies that tested whether acoustic enhancements to the current tone could convey clinically important ranges more directly, without necessarily using auditory alarms. The studies cover the use of enhanced variable-pitch pulse oximeter tones for neonatal and adult use. Compared with current tones, the characteristics of the enhanced tones represent improvements that are both clinically relevant and statistically significant. We outline the benefits of enhanced tones, as well as discuss constraints of which developers of enhanced tones should be aware if enhancements are to be successful.

Defining information needs in neonatal resuscitation with work domain analysis

OBJECTIVE

To gain a deeper understanding of the information requirements of clinicians conducting neonatal resuscitation in the first 10 min after birth.

BACKGROUND

During the resuscitation of a newborn infant in the first minutes after birth, clinicians must monitor crucial physiological adjustments that are relatively unobservable, unpredictable, and highly variable. Clinicians' access to information regarding the physiological status of the infant is also crucial to determining which interventions are most appropriate. To design displays to support clinicians during newborn resuscitation, we must first carefully consider the information requirements.

METHODS

We conducted a work domain analysis (WDA) for the neonatal transition in the first 10 min after birth. We split the work domain into two 'subdomains'; the physiology of the neonatal transition, and the clinical resources supporting the neonatal transition. A WDA can reveal information requirements that are not yet supported by resources.

RESULTS

The physiological WDA acted as a conceptual tool to model the exact processes and functions that clinicians must monitor and potentially support during the neonatal transition. Importantly, the clinical resources WDA revealed several capabilities and limitations of the physical objects in the work domain-ultimately revealing which physiological functions currently have no existing sensor to provide clinicians with information regarding their status.

CONCLUSION

We propose two potential approaches to improving the clinician's information environment: (1) developing new sensors for the information we lack, and (2) employing principles of ecological interface design to present currently available information to the clinician in a more effective way.

Smooth or Stepped? Laboratory Comparison of Enhanced Sonifications for Monitoring Patient Oxygen Saturation

BACKGROUND

The pulse oximeter (PO) provides anesthesiologists with continuous visual and auditory information about a patient's oxygen saturation (SpO₂). However, anesthesiologists' attention is often diverted from visual displays, and clinicians may inaccurately judge SpO₂ values when relying on conventional PO auditory tones. We tested whether participants could identify SpO₂ value (e.g., "97%") better with acoustic enhancements that identified three discrete clinical ranges by either changing abruptly at two threshold values (stepped-effects) or changing incrementally with each percentage value of SpO₂ (smooth-effects).

METHOD

In all, 79 nonclinicians participated in a between-subjects experiment that compared performance of participants using the stepped-effects display with those who used the smooth-effects display. In both conditions, participants heard sequences of 72 tones whose pitch directly correlated to SpO₂ value, and whose value could change incrementally. Primary outcome was percentage of responses that correctly identified the absolute SpO₂ percentage, ±1, of the last pulse tone in each sequence.

RESULTS

Participants using the stepped-effects auditory tones identified absolute SpO₂ percentage more accurately (M = 53.7%) than participants using the smooth-effects tones (M = 47.9%, p = .038). Identification of range and detection of transitions between ranges showed even stronger advantages for the stepped-effects display (p < .005).

CONCLUSION

The stepped-effects display has more pronounced auditory cues at SpO₂ range transitions, from which participants can better infer absolute SpO₂ values. Further development of a smooth-effects display for this purpose is not necessary.