Table 2.
Polysomnography studies of sleep in critical care patients
| Author(s) (year) | Number of patients | Critical care population | Duration | Sedation | Number ventilated | Intervention monitored | Practical difficulties |
| Johns et al. (1974) [14] | 4 | Surgical | Continuously for first few days | Opioids and nocturnal hypnotics | Not stated | No | None identified |
| Karacan et al. (1974) [15] | 4 | Medical | Continuous × 24 to 108 hours | Majority nocturnal hypnotics | None | No | None identified |
| Hilton (1976) [16] | 10 | Medical | Continuous × 48 hours | Not stated | Not stated | No | Data incomplete for 3/10 patients |
| Orr and Stahl (1977) [17] | 9 | Surgical | 3–4 nights | Majority nocturnal opioids and/or benzodiazepines | Not stated | No | Considerable muscle artifact across all recording channels |
| Broughton and Baron (1978) [18] | 12 (10 reported) | Medical | Majority 9 nights but up to 13 | Majority nocturnal benzodiazepines and/or barbiturates | None | No | Two patients withdrew due to inconvenience of monitoring |
| Aurell and Elmqvist (1985) [19] | 9 | Surgical | Continuous × approximately 72 hours | Opioid and local analgesia, some benzodiazepines | 2/9 | No | None identified |
| Richards and Bairnsfathera (1988) [20] | 10 | Medical | 1–3 nights | Not stated | None | No | One patient withdrew from study after EEG electrodes were positioned |
| Fontaine (1989) [21] | 20 | Trauma | 1 night | All received opioid and nocturnal benzodiazepine | 1/20 | No | None identified |
| Edwards and Schuring (1993) [22] | 21 | Medical | 1 night | 18/21 nocturnal benzodiazepine/barbiturate | 20/21 | No | None identified |
| Gottschlich et al. (1994) [23] | 11 | Burns | Continuous × 24 hours (repeated intervals) | Not stated | All | No | None identified |
| Aaron et al. (1996) [24] | 6 | Medical | Continuous × 24 hours 2/6, × 48 hours 4/6 | 3/6 received hypnotics/opioids | None | No – effect of environmental disturbances recorded | None identified |
| Richards et al.a(1996) [25] | 9 | Medical | 1 night | 3/9 received nocturnalbenzodiazepines | None | No | None identified |
| Richardsb(1998) [26] | 69 | Medical | 1 night | Minority received nocturnal hypnotics | None | Yes – relaxation techniques | Standard sensitivity and paper speed settings for polygraph unavailable and were therefore altered; 23/94 refused most commonly due to study/polysomnography being an additional stressor. Only one patient could be studied per night.c |
| Cooper et al. (2000) [27] (20 reported) | 26 | Medical | Continuous × 24 hours | Majority received opioids, benzodiazepines or haloperidol | All | No | Six patient records unable to score due to technical difficulties: electrical artifact (4), respiratory artifact (2). |
| Richards et al.b(2000) [11] | 70 | Medical | 1 night | Minority received nocturnalhypnotics | None | No – see above | cSee above entry |
| Freedman et al. (2001) [28] | 22 | Medical | Continuous × 24 hours 14/22, × 48 hours 8/22 | 8 of 22 intermittent benzodiazepine or opioid | 20/22 | No – effect of environmental disturbances recorded | Five patient records unable to be scored due to sepsis-induced alterations to EEG pattern |
| Parthasarathy and Tobin (2002) [6] | 11 | Medical | 1 night | All received sedatives | All | Yes – mode of ventilation | None identified |
| Richards et al.b(2002) [29] | 64 | Medical | 1 night | Minority received nocturnal hypnotics | None | No – see above | cSee above entry |
| Valente et al. (2002) [30] | 24 | Neuro-Trauma | Continuous × 24 hours | At least 24 hours post-sedation discontinued | Not stated | No | None identified |
| Gabor et al. (2003) [4] | 7 | Medical/Trauma | Continuous × 24 hours | Majority opioids, benzodiazepines, and/or antipsychotics | All | No – effect of environmental disturbances recorded | None identified |
| Cochen et al. (2005) [31] | 17 | Medical/Trauma | 1–2 nights, some daytime | None | All | No | 4/31 sleep recordings not scored due to electrical artifact |
| Hardin et al. (2006) [32] | 18 | Medical | Continuous × 24 hours | 6/18 received intermittent sedation only and were awake and alert, 12/18 received continuous sedation | All | No – group comparison between neuromuscular blocking agents, continuous sedation, and intermittent sedation | Modified delta criteria used. Unknown quantity of epochs scored as non-classifiable. Recorder malfunctioned in one patient |
| Bosma et al. (2007) [33] | 13 | Medical/Surgical | 2 nights (crossover study) | 3/13 received opioids and 2 received All haloperidol | Yes – pressure support versus proportional assist controlled ventilation and patient-ventilator dysynchrony | None identified |
a,bMultiple reports refer to a single polysomnography study. EEG, electroencephalogram.