SummaryOur study examined the effectiveness of pulse oximetry sonification enhanced with acoustic tremolo and brightness to help listeners differentiate clinically relevant oxygen saturation ranges. In a series of trials lasting 30 s each, 76 undergraduate participants identified final oxygen saturation range (Target: 100% to 97%; Low: 96% to 90%; Critical: 89% and below), and detected threshold transitions into and out of the target range using conventional sonification (n = 38) or enhanced sonification (n = 38). Median (IQR [range]) accuracy for range identification with the conventional sonification was 80 (70-85 [45-95])%, whereas with the enhanced sonification it was 100 (99-100 [80-100])%; p < 0.001. Accuracy for detecting threshold transitions with the conventional sonification was 60 (50-75 [30-95])%, but with the enhanced sonification it was 100 (95-100 [75-100]%; p < 0.001. Participants can identify clinically meaningful oxygen saturation ranges and detect threshold transitions more accurately with enhanced sonification than with conventional sonification. IntroductionUsing the variable pitch auditory signal of a pulse oximeter, a clinician can detect changes in a patient's heart rate and oxygen saturation level (SpO 2 ) while performing other visually demanding tasks, or when the visual display of the pulse oximeter is out of the line of sight [1][2][3]. However, clinicians cannot accurately estimate the absolute level of SpO 2 without reference to the pulse oximeter's visual display [4]. With the additional cognitive load of other clinical tasks and increased noise, it becomes even more difficult to estimate SpO 2 levels [5].The auditory signal used by pulse oximeters is termed a 'sonification' -a continuous mapping of numerical values or relationships in patient data into comprehensible auditory dimensions [6][7][8]. The pulse oximetry sonification varies pitch alone to convey information about SpO 2 . The rate of the tones represents heart rate and rhythm, and the pitch of the tones represents SpO 2 . Current pulse oximeter sonifications rely on a clinician's ability to perceive relative pitch to infer changes in SpO 2 direction, and their ability to perceive absolute pitch to infer absolute SpO 2 levels [4,5,12,13]. Commercial pulse oximeters map linear increments of SpO 2 to either fixed or percentage increments in sound frequency (perceived as pitch); the former results in a linear mapping, whereas the latter results in a logarithmic mapping [14,15]. A logarithmic scale creates approximately equal-appearing pitch intervals [4,9,14]. Under test conditions, clinicians can identify absolute SpO 2 levels more accurately when SpO 2 is mapped to a logarithmic scale than to a linear scale [12]. However, remedies to date have generally focused on participants' ability to infer absolute SpO 2 levels (e.g. 98%) rather than clinically relevant ranges (e.g. low).In this study, we enhanced a conventional pulse oximetry sonification [14] by adding tremolo and, in extreme cases, brightness to each tone when ...

This study investigated the efficacy of a new ilioinguinal-transversus abdominis plane block when used as a component of multimodal analgesia. We conducted a prospective, triple-blind, placebo-controlled randomised study of 100 women undergoing elective caesarean section. All women had spinal anaesthesia with hyperbaric bupivacaine, 15 μg fentanyl and 150 μg morphine, as well as 100 mg diclofenac and 1.5 g paracetamol rectally. Women were randomly allocated to receive the ilioinguinal-transversus abdominis plane block or a sham block at the end of surgery. The primary outcome was the difference in fentanyl patient-controlled analgesia dose at 24 h. Secondary outcomes included postoperative pain scores, adverse effects and maternal satisfaction. The cumulative mean (95%CI) fentanyl dose at 24 h was 71.9 (55.6-92.7) μg in the ilioinguinal-transversus abdominis group compared with 179.1 (138.5-231.4) μg in the control group (p < 0.001). Visual analogue scale pain scores averaged across time-points were 1.9 (1.5-2.3) mm vs. 5.0 (4.3-5.9) mm (p = 0.006) at rest, and 4.7 (4.1-5.5) mm vs. 11.3 (9.9-13.0) mm (p = 0.001) on movement, respectively. Post-hoc analysis showed that the ilioinguinal-transversus abdominis group was less likely to use ≥ 1000 μg fentanyl compared with the control group (2% vs. 16%; p = 0.016). There were no differences in opioid-related side-effects or maternal satisfaction with analgesia. The addition of the ilioinguinal-transversus abdominis plane block provides superior analgesia to our usual multimodal analgesic regimen.

Interruptions have been associated with adverse events in healthcare. However, supporting studies are descriptive and atheoretical rather than explanatory, and they seldom show that interruptions compromise patient safety. Prospective memory may provide useful theoretical background. We analyzed video from a full-scale patient simulator for factors enhancing or inhibiting anesthesiologists' prospective memory performance. The critical task was to remember to cross check a unit of blood against the patient before administering the blood. All 12 participants were interrupted by the surgeon when the blood arrived. Only participants who self-initiated the retrieval (n = 3), or returned their full attention to the transfusion task and saw the blood bag label (n = 7), remembered the check. The result can be explained with findings from prospective memory literature.

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Adequate postoperative analgesia is a key to earlier recovery from open surgery. This work investigated the pain control and quality of patient recovery after hepatectomy to evaluate the modified continuous serratus anterior plane block (called low SAPB) for postoperative analgesia. Patients and Methods: This single-center, blinded, randomized, controlled study included 136 patients who underwent hepatectomy under general anesthesia. For postoperative analgesia, the patients in the SAPB group were given a continuous low SAPB at the 7th intercostal space in the right mid-axillary line, and the patients in the control group were given continuous intravenous opioid analgesia. The numeric pain rating scale (NPRS) was used for pain assessment. The postoperative assessment focused on the remedial drug consumption, the occurrence of adverse postoperative analgesic reactions, and the quality of patient recovery evaluated with the QoR-15 questionnaire. Results: Compared to the controls, the SAPB patients had significantly lower NPRS scores at 12 h and 24 h at rest and 6 h, 12 h, and 24 h in motion, and a longer time to first use of remedial analgesics at 24 h, and higher overall QoR-15 scores at 24 h [124 (121, 126) vs 121 (120, 124)] and 48 h [129 (126, 147) vs 126 (125, 128)], after surgery. There was no significant difference in the incidence of analgesia-related adverse reactions between the two groups. Conclusion:The continuous low SAPB could achieve superior pain control, especially for motor pain, to intravenous opioid analgesia during the first 24 h post-surgery. Even with no significant difference in the incidence of postoperative adverse reactions, patients with continuous low SAPB appeared to have a higher quality of recovery in the first two days post-surgery than patients with continuous intravenous analgesia.

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