Risk in pediatric anesthesia can be conveniently classified as minor or major. Major morbidity includes cardiac arrest, brain damage and death. Minor morbidity can be assessed by clinical audits with small patient samples. Major morbidity is rare. It is best assessed by very large clinical studies and by review of closed malpractice claims. Both minor and major morbidity occur most commonly in infants and children under three, especially those with severe co-morbidities. Knowledge of risk profiles in pediatric anesthesia is a starting point for the reduction of risk.

Standards of lithium monitoring require further improvement. Locally agreed practice guidelines are helpful but patients on lithium should be in continuing contact with an experienced psychiatrist.

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 ...

Enhanced sonifications are more informative than conventional sonification. The implication is that they might allow anaesthetists to judge better when desaturation decreases below, or returns to, a target range.