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Background: Assessing pain in critically ill patients is difficult. Skin conductance variability (SCV), induced by the sympathetic response to pain, has been suggested as a method to identify pain in poorly communicating patients. However, SCV, a derivate of conventional skin conductance, could potentially also be sensitive to emotional stress. The purpose of the study was to investigate if pain and emotional stress can be distinguished with SCV.Methods: In a series of twelve 1-min sessions with SCV recording, 18 healthy volunteers were exposed to standardized electric pain stimulation during blocks of positive, negative, or neutral emotion, induced with pictures from the International Affective Picture System (IAPS). Additionally, authentic intensive care unit (ICU) sound was included in half of the sessions. All possible combinations of pain and sound occurred in each block of emotion, and blocks were presented in randomized order.Results: Pain stimulation resulted in increases in the number of skin conductance fluctuations (NSCF) in all but one participant. During pain-free baseline sessions, the median NSCF was 0.068 (interquartile range 0.013-0.089) and during pain stimulation median NSCF increased to 0.225 (interquartile range 0.146-0.3175). Only small increases in NSCF were found during negative emotions. Pain, assessed with the numeric rating scale, during the sessions with pain stimulation was not altered significantly by other ongoing sensory input.Conclusion: In healthy volunteers, NSCF appears to reflect ongoing autonomous reactions mainly to pain and to a lesser extent, reactions to emotion induced with IAPS pictures or ICU sound. [ABSTRACT FROM AUTHOR]

Background Many intensive care unit ( ICU) patients describe noise as stressful and precluding sleep. No previous study in the adult setting has investigated whether room size impacts sound levels or the frequency of disruptive sounds. Methods A-frequency S-time weighted equivalent continuous sound ( LASeq), A-frequency S-time weighted maximum sound level ( LASmax) and decibel C peak sound pressure ( LCpeak) were measured during five 24-h periods in each of the following settings: three-bed room with nursing station ( NS) alcove, single-bed room with NS alcove (1- BR with NSA) and single-bed room with bedside NS. Cumulative restorative time ( CRT) (> 5 min with LASmax < 55 dB and LCpeak < 75 dB) was calculated to describe calm periods. Two 8-h bedside observations were performed in each setting in order to note the frequency and sources of disruptive sounds. Results Mean sound pressure levels ( LASeq) ranged between 52 and 58 dBA, being lowest during night shifts. There were no statistically significant differences between the room types in mean sound levels or in CRT. However, disruptive sounds were 40% less frequent in the 1- BR with NSA than in the other settings. Sixty-four percent of disruptive sounds were caused by monitor alarms and conversations not related to patient care. Conclusions Single-bed rooms do not guarantee lower sound levels per se but may imply less frequent disruptive sounds. Sixty-four percent of disruptive sounds were avoidable. Our findings warrant sound reducing strategies for ICU patients. [ABSTRACT FROM AUTHOR]