The Effect of the Lunar Cycle on ED Patient Volume
Date First Published:
July 29, 2007
Last Updated:
August 3, 2007
Report by:
Wesley R Young, ER Resident (Grand Rapids Medical Education & Research/Michigan State University)
Search checked by:
Jeffrey S. Jones, MD, Grand Rapids Medical Education & Research/Michigan State University
Three-Part Question:
Can the number of [Emergency Room visits] and the [phase of the lunar cycle] be linked [ showing more visits during the full moon]?
Clinical Scenario:
Your last evening shift in the emergency department was particularly busy. The charge nurse remarked, "There must be a full moon out tonight." You wonder if there is truly any link between ED census and the lunar phases, or is this belief simply a myth.
Search Strategy:
Medline 1966-07/07 using the OVID interface, Cochrane Library (2007), PubMed clinical queries.
Search Details:
[(exp moon OR lunar.mp) AND (exp emergencies OR emergency.mp OR emergency medicine OR exp emergency medical services OR exp emergency service, hospital)]. LIMIT to human AND English
Outcome:
35 papers were found, of which 29 papers were irrelevant to the study question or of insufficient quality for inclusion.
Relevant Paper(s):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| Full moon and ED Patient Volumes: Unearthing a Myth Thompson DA. Adams SL 1996 March United States | All patients seen in the emergency room of a community hospital over 4 years | This study was a retrospective analysis of effect of the lunar cycle on the number of ED visits and hospital admissions | Number of Patients seen in ER on each day of the lunar cycle | There was no statistical increase during the full moon | The study does not break the patients up by complaint and demographics |
| Percentage of Patients arriving by ambulance on each day of the lunar cycle | There was no statistical increase during the full moon | ||||
| Percentage of total patients that wereadmited during each day of the lunar cycle | There was no statistical increase during the full moon | ||||
| Percentage of total patients that wereadmited to a monitored unit during each day of the lunar cycle | There was no statistical increase during the full moon | ||||
| The Influence of Lunar Phenomena on the Incidence of Emergency Cases. Wolbank S. Prause G. Smolle-Juettner F. Smolle J. Heidinger D. Quehenberger F. Spernbauer P 2003 July Austria | Patients with life threatening condition that were evaluated by the staff of 4 emergency vehicles in an urban community | This is a retrospective study looking at the relationship of number of emergency cases and the phase of the moon, distance of moon from earth, and in regards to the sign of the Zodiak | The influence of the Lunar cycle to the number of emergency cases | No corelation between the number of emegency cases and the phase of the moon | The tables are difficult to follow. They are not very clear on who was evaluating these patients and determining who was sick and who was not. Half of the patients evaluated where determined not to be sick enough to be included in the study |
| The influence of the distance the moon is from the earth on the number of emergency cases | There is no significant relationship between the distance the moon is from the earth and the number of emergency cases | ||||
| Does the sign of the zodiak influence the number and type of emergency cases | There was no relationship between the sign of the Zodiak and the number of type of emergency cases | ||||
| The full moon and admission to emergency rooms Zargar M. Khaji A. Kaviani A. Karbakhsh M. Yunesian M. Abdollahi M 2004 May. India | 5800 trauma patients, 3543 excluded due to lack of data seen at three large medical centers in Tehran | A retrospective study evaluating the effect of the lunar cycle on the number of trauma admissions to the ER, the GCS score, and the severity of injuries | The relationship of the Full moon on the number of Trauma admissions to the ER | There was not relationship between the number of ER trauma admissions and the full moon | The definition of the severity of the trauma is lacking. This study is only looking at trauma pts |
| The relationship of the patient's GCS score and the Full moon | There was not a significant lower average GCS score on the full moon | ||||
| The relationship between the severity of the injury and the Full moon | The severity of injury was not increased during the full moon |
Author Commentary:
Numerous articles have been published examining the relationship between the moon and human behavior. The findings of these studies have been contradictory and confusing. Some of these studies did not control for confounding variables such as month or day of the week. Another potential problem in the evaluation of the lunar effect is inadequate sample size. A large sample size in necessary to be able to detect weak trends.
Trauma or psychiatric cases that arrive on full moon days may be more memorable to staff members whose expectations were piqued. This serves as positive reinforcement for their belief in lunar effects.
Trauma or psychiatric cases that arrive on full moon days may be more memorable to staff members whose expectations were piqued. This serves as positive reinforcement for their belief in lunar effects.
Bottom Line:
The presence of a full moon appears to have no effect on ED patient volume, ambulance runs, admissions to the hospital, or admissions to a monitored unit. The expression, "There must be a full moon out tonight," will likely remain in emergency medicine folklore. However, the belief that the ED is busier during the full moon cannot be substantiated.
References:
- Thompson DA. Adams SL. Full moon and ED Patient Volumes: Unearthing a Myth
- Wolbank S. Prause G. Smolle-Juettner F. Smolle J. Heidinger D. Quehenberger F. Spernbauer P. The Influence of Lunar Phenomena on the Incidence of Emergency Cases.
- Zargar M. Khaji A. Kaviani A. Karbakhsh M. Yunesian M. Abdollahi M. The full moon and admission to emergency rooms