Patients undergoing surgery at night are much more likely to develop serious complications than those applied during the day, a study has found.
Potentially life-threatening events, such as a dangerous fall in blood pressure or abnormal heart rhythms, occur in 44% of patients whose procedures take place between 20.00 and 7.59 hours.
This is comparable to a lower incidence of 34% of such "side effects" in patients undergoing surgery between 8.00 and 19.59 hours, according to a large-scale global study.
Patients who operate during the night are also more at risk of dying, although the difference disappeared when the researchers looked at how serious the people who underwent the operation were ill.
Experts said that the higher risk for nocturnal patients was related to the fact that medical staff were tired and fewer staff were at work and that those who underwent surgery were sicker.
"The findings of this study will be a concern for all clinicians," said Dr. William Harrop-Griffiths, the chair of the clinical quality and research board at the Royal College of Anesthetists.
"It may well be that the increased incidence noted in this study is largely the result of physicians' fatigue and other human factors."
The study looked at 9,861 adults who were operated in 146 hospitals in 29 countries, including 21 in England and Scotland. 9,306 operations took place during the day and 555 at night.
Side effects are those in which the patient is involved and which occur during the operation and urgent action must be taken to prevent damage or to be fatal. For example, if the patient's blood pressure drops to a level that can damage a vital organ, such as the kidney, or cause a stroke.
In the study, 26.2% of patients experienced a sudden drop in blood pressure during the day compared with 33.3% of night-time patients. While 21.9% of the previous group received medication to increase their blood pressure, this was more often required in 31.8% of cases, more often at night.
Similarly, the oxygen level in the patient's blood decreased worryingly low in 3.8% of cases during the day, but in 6.1% of those whose surgery took place at night.
Prof. Gary Mills, a co-author of the paper, published in the British Journal of Anesthesia, said: "Patients who undergo surgery at night are clearly at greater risk of complications and death. avoid many night operations, but there will be cases where it is more risky to wait to get it. "
NHS hospitals should minimize night operations where possible, advised Mills. "You have to be careful with the tax you put on the staff in terms of overnight operations because fewer staff are available [and] things do not work as well as during the day. "
The fact that patients who undergo surgery during the night are often sicker than during the day is an important reason for the differences revealed, he added. Although only 10% of the operations were carried out during the day as urgent or emergency, they formed 26% of the overnight stays that were done during the night.
Prof. Neil Mortensen, the vice president of the Royal College of Surgeons, said that the "increased risk of injury or injury to patients who have nighttime operations is partially due to hospital resources, such as staff and access to equipment, because more limited at night.
"There has been a shift in work in the UK over the past decades – most surgeons in NHS hospitals will not work after midnight, unless the condition of a patient immediately causes life, limb or organ damage. is. "
Harrop-Griffiths said that impaired cognitive skills in anesthesiologists who were in the mid-sixties or even older can also help explain the differences.
"In the course of time, the mental flexibility, skills and response times of all physicians, including surgeons and anesthetists, diminish, and vigilance and some aspects of cognitive function become more variable with age, the ability to engage in night work. fit is reduced and fatigue can further deteriorate the performance of older doctors, "he added.
• This article was amended on 9 February 2019. 9,306 of the investigated operations took place during the day and 555 during the night, not the other way as originally mentioned.