Clinical Editor's Corner: Kern

Are You Too Sleepy to Be Safe? The Role of Sleep Deprivation on Outcomes in the Cardiac Cath Lab

Morton J. Kern, MD, MSCAI, FACC, FAHA

Morton J. Kern, MD, MSCAI, FACC, FAHA

I’m going out on a limb here, but I would say that most cath lab staff at one time or another have gone to work with a sleep debt and muscled their way through the day (or night) while overcoming the ill effects of sleep deprivation. Although I’m no longer on ST-elevation myocardial infarction (STEMI) call, I still have episodic sleep deprivation because of binging on late-night TV provoked by an after-dinner caffeine jolt. A recent article on the subject of sleep deprivation in the cath lab1 stimulated my interest and I thought I would share these observations with our dedicated cath lab team members.

My Question: Is Sleep-Deprived Cath Lab Staff at High Risk for Errors?

For sleep-deprived operators performing emergency procedures in the middle of the night, clinical outcomes may be less than optimal. Unfortunately, our knowledge of such outcomes is limited. This issue was addressed by physicians at the Minneapolis Heart Institute. Iverson et al1 reported on the impact of sleep deprivation and outcomes of percutaneous coronary intervention (PCI) in 12,680 daytime PCIs from 2009 to 2016, of which 3% (n=367) were performed by sleep-deprived operators.

How was Sleep Deprivation (SD) Defined?

In general, SD is loosely defined as insufficient sleep to function normally.2 However, for study purposes, Iverson et al1 defined SD as acute or chronic. Acute SD was applied when an operator performed only one nighttime PCI in the preceding seven days. Chronic SD was noted when the operator had performed more than one nighttime PCI in seven days. The length of sleep interruption was classified according to the length of nighttime PCI preceding sleep. PCIs lasting <35 minutes were short; PCIs >35 minutes were considered long sleep interruptions.

SD Study Results

The patient groups treated by the sleep/non-sleep deprived operators were clinically similar. Compared to patients undergoing PCI by non-sleep deprived operators, those performed by sleep-deprived operators were younger, more were Caucasian, and more had ST segment elevation. Most importantly, in-hospital death rates and hospital complications including bleeding were not different between the 2 groups. Iverson et al1 concluded that in this large, single-center study that SD did not appear to adversely impact PCI outcomes. It is also worth noting that although SD does not adversely impact patients, the technical aspects of cath lab operations were affected. For example, there was an increase in the number of needle sticks that occurred, which may be due to decreased psychomotor and cognitive skills. Lack of sleep also increases stress for the laboratory as a whole, and decreases memory and recall of some important activities.

Adverse Health Effects of Sleep Deprivation

Sleep deprivation impacts physician and staff health alike. Sleep deprivation has adverse health effects both inside and outside the cardiac cath lab. Consider the bus driver, pilot, or soldier. Workplace sleep deprivation with assignment inattention can be fatal during air or ground transportation, or in conditions needing the use of firearms. Sleep deprivation increases the risk for developing metabolic derangements, including type 2 diabetes mellitus, hypertension, and abnormal blood lipids.3,4 There are several causes of sleep deprivation: voluntary behavior, personal obligations (e.g., a person providing home care for a sick relative), prolonged work hours, and a variety of medical problems. Many single-car fatal and non-fatal motor vehicle accidents have been attributed to SD. Many well-known occupational hazards in interventional cardiology include orthopedic injuries, infectious hazards due to needle sticks, sharp injuries), and radiation exposure.5 SD and its consequences should be added to this list (Table 1).

How Much Sleep Does a Person Usually Need and Who’s at Risk for SD?

From the American Academy of Sleep Medicine (AASM)2, the following interesting facts are provided. The amount of sleep that a person needs varies among individuals. On average, most adults need about 7-8 hours of sleep each night to feel alert and well rested. Teenagers and children need an average of about 9 hours of sleep per night.

Who’s at risk for sleep deprivation? Everyone, under the right conditions, but caregivers, shift workers, those with concurrent sleep disorders (e.g., sleep apnea, psychophysiological insomnia, periodic limb movements, and restless legs), and people with Parkinson’s disease are at higher risk of SD.

How to Recognize Sleep Deprivation

Those likely to have SD will demonstrate excessive daytime sleepiness, common during a meeting or class. This degree of severe sleepiness can be a safety hazard, causing drowsy driving and workplace injuries. The other signs/symptoms of sleep deprivation include mood changes (e.g., irritability, lack of motivation, anxiety, and symptoms of depression). SD can produce a change in performance with lack of concentration, attention deficits, reduced vigilance, and delayed reaction times, distractibility, lack of energy, fatigue, restlessness, lack of coordination, poor decisions, increased errors, and forgetfulness.

Sleep Deprivation – Is it Really a “No Harm, No Foul” Situation?

From Iverson’s study1, cath labs and their staff may be somewhat reassured that in-hospital mortality, complications, and bleeding rates were not different for sleep-deprived operators. These results are consistent with previous small, single-center studies that also found no difference in the safety or efficacy profiles when comparing PCIs done during the day with those done in the middle of the night.   

Dr. James Blankenship6 provided editorial insight into Iverson’s study and reminded us that although the safety of PCI for those practicing with sleep deprivation is generally high, it is important for cath lab managers and interventionalists to take simple steps in order to minimize risk to the patients when day-after-call PCIs are performed. Data from the National Cardiovascular Data Registry’s CathPCI registry examining 1,509,096 patients found no difference in PCI success rates, but 19% reported an excess bleeding rate in PCIs performed by an operator doing two or more PCIs the night before.7 Sleep deprivation studies are often limited by their retrospective nature and the inability to quantitate the extent of sleep deprivation by different operators. It is possible that other operators not working the night before an on-call PCI may also be sleep deprived, but we will never know who they are.

Dr. Blankenship was helpful in concluding that although the results of studies of sleep deprivation did not guarantee that all hospitals and operators can provide safe “day-after-call-PCI”, the practice does appear to be safe; however, policies that would ensure that all personnel have sufficient capacity to function in a safe manner the next day should include the following:

  1. Planning of physicians’ schedules so that interventionalists are not in the cath lab after a night on call and if they are, they may be assigned to more elective than emergency cases.
  2. Long and difficult cases such as chronic total occlusions (CTOs) may not be suitable for these SD operators.
  3. Consider nap time. Leave the hospital early after your call, if possible, to catch up on rest.
  4. Plan cath lab technologists’ schedules accordingly, so that the on-call team from the night before is not assigned to work in the most difficult cases with the interventionalist who may be sleep deprived. Not everyone on the same team should be up all night and then working all day the next day.
  5. Be self-aware if you are not working at 100%, either as the operator or as the team. Consider ‘tapping out’, or avoiding long and complicated cases.   
  6. Consider assigning ad hoc difficult cases to another, more rested operator.
  7. Ask for help. Your colleagues, fellows, nurses, and technologists can step in if you are feeling at less than 100% and catch any mistakes that might be due to sleep deprivation.

While Iverson and colleagues1 do not recommend any form of restrictions on physicians’ call schedules for interventional cardiology, the laboratories should review their organizational approach to make the on-call/night call case load manageable.

The Bottom Line

There is little doubt we should pay more attention to our own and our team’s health, which includes getting sufficient rest to be at the top of our game when called to duty. The AASM provides some guidance for coping with sleep deprivation (Table 2).2 Finally, if you got sleepy reading this editor’s page, you may indeed be sleep deprived. (It may be that I’m boring, but get some rest anyway.)

Disclosure: Dr. Kern reports he is a consultant for Abiomed, Abbott Vascular, Philips Volcano, ACIST Medical, Opsens Inc., and Heartflow Inc.


1. Iverson A, Stanberry L, Garberich R, et al. Impact of sleep deprivation on the outcomes of percutaneous coronary intervention. Catheter Cardiovasc Interv. 2018; 92: 1118-1125

2. Sleep Deprivation. A statement from the American Academy of Sleep Medicine. Available online at Accessed December 6, 2018.

3. Consensus Conference Panel, Watson NF, Badr MS, Belenky G, et al. Recommended amount of sleep for a healthy adult: a joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. J Clin Sleep Med. 2015; 11: 591-592.

4. Kecklund G, Axelsson J. Health consequences of shift work and insufficient sleep. BMJ. 2016; 355: i5210.

5. Chambers CE. Occupational health risks in interventional cardiology: expected inherent risk or preventable personal liability? JACC Cardiovasc Interv. 2015; 8: 628-630.

6. Blankenship JC. Day-after PCI: Safe for the patient but perhaps not for the interventionalist. Catheter Cardiovasc Interv. 2018; 92: 1126-1127.

7. Aronow HD, Gurm HS, Blankenship JC, et al. Middle-of-the-night percutaneous coronary intervention and its association with percutaneous coronary intervention outcomes performed the following day: an analysis from the National Cardiovascular Data Registry. JACC Cardiovasc Interv. 2015 Jan; 8(1 Pt A): 49-56.