We’ve done a whole host of columns on the risks of surgery in patients with obstructive sleep apnea (OSA), recognized or unrecognized (see the list at the end of today’s column). A couple key principles in managing such patients are to (1) use multimodality analgesic techniques so that post-op use of opioids can be minimized and (2) minimize the use of other drugs that might promote airway collapse or suppress respiration. Choice of anesthesia for such patients has always been an item for discussion but there has been no consensus and most such discussions are based on theoretical considerations, “expert” opinions, and anecdotal case reports rather than being evidence-based.
Now researchers from The Hospital for Special Surgery have demonstrated that choice of anesthesia does make a difference in outcomes (Memtsoudis 2013). They found that using regional anesthesia instead of general anesthesia in patients with sleep apnea undergoing total joint replacement decreased major complications by 17%. They analyzed data from approximately 400 hospitals in the United States who submit data to a large administrative database (Premier Inc) and looked at the types of anesthesia used in over 30,000 sleep apnea patients undergoing primary hip or knee arthroplasty. Approximately 11% of cases were performed under neuraxial, 15% under combined neuraxial and general, and 74% under general anesthesia. Major complication rates for those 3 types of anesthesia were 16.0%, 17.2%, and 18.1%, respectively. After adjustment, the risk of major complications for those undergoing surgery under neuraxial or combined neuraxial-general anesthesia was 17% lower than those undergoing general anesthesia.
Though this was a retrospective study rather than a randomized controlled trial it does provide at least some evidence that regional anesthesia may be preferable in this patient population, at least for major joint replacement surgery. Whether regional or neuraxial techniques have fewer major complications in other types of surgery in patients with OSA needs to be addressed in further studies.
Our prior columns on obstructive sleep apnea in the perioperative period:
Patient Safety Tips of the Week:
June 10, 2008 “Monitoring the Postoperative COPD Patient”
August 18, 2009 “ ”
August 17, 2010 “ ”
July 13, 2010 “Postoperative Opioid-Induced Respiratory Depression”
February 22, 2011 “Rethinking Alarms”
November 22, 2011 “Perioperative Management of Sleep Apnea Disappointing”
May 22, 2012 “Update on Preoperative Screening for Sleep Apnea”
February 12, 2013 “CDPH: Lessons Learned from PCA Incident”
February 19, 2013 “Practical Postoperative Pain Management”
March 26, 2013 “Failure to Recognize Sleep Apnea Before Surgery”
What’s New in the Patient Safety World columns:
November 2010 “More on Preoperative Screening for Obstructive Sleep Apnea”
Memtsoudis SG, Stundner O, Rasul R, et al. Sleep Apnea and Total Joint Arthroplasty under Various Types of Anesthesia: A Population-Based Study of Perioperative Outcomes. Regional Anesthesia & Pain Medicine.2013; POST AUTHOR CORRECTIONS, published online ahead of print 3 April 2013
SAMHSA (Substance Abuse and Mental Health Services Administration) and the Drug Abuse Warning Network (DAWN), a public health surveillance network that monitors drug-related ED visits in the US, on May 1, 2013 issued a report noting that emergency department visits for adverse reactions involving zolpidem increased 220% from 2006 to 2010. Females accounted for two-thirds of the visits and patients over the age of 45 accounted for three-quarters of the visits (those over age 65 accounting for about one-third). Other drugs combined with the zolpidem (most often narcotic pain relievers or anti-anxiety medications or other sleep medications) were noted in about half the cases.
And last month the FDA (FDA 2013) approved new label changes and dosing for zolpidem products and a recommendation to avoid driving the day after using Ambien CR. The label updates include the recommendations of the FDA back in January 2013 to lower the initial dose of intermediate-release zolpidem-containing products (Ambien, Edular) in women to 5 mg (5 mg or 10 mg may be the initial dose in men) and that the initial dose of Ambien-CR be 6.25 mg for women (and either 6.5 mg or 12.5 mg for men). Though they do talk about increasing the dose if the lower dose is ineffective, they warn that use of the higher dose may increase the risk of next-day impairment of driving or other activities that require full alertness. In addition, the FDA warns that patients who take zolpidem extended-release (Ambien-CR) in either the 6.5 mg or 12.5 mg dose should not drive or engage in other activities that require complete mental alertness the day after taking the drug.
We’ve tried for years, with varying degrees of success, to get physicians to use sedative/hypnotic drugs less frequently in hospitalized patients. We’ve long recommended that routine “prn” orders for such not be included on standard order sets (see our August 2009 What’s New in the Patient Safety World column “Bold Experiment: Hospitals Saying No to Sleep Meds”). ISMP has echoed that approach (see our March 23, 2010 Patient Safety Tip of the Week “ISMP Guidelines for Standard Order Sets”). In our May 2012 What’s New in the Patient Safety World column “Safety of Hypnotic Drugs” we discussed many of the safety issues related to sedative/hypnotic drugs. They frequently are contributing factors to patient falls, delirium, and opioid-related respiratory depression. Sometimes we’ll see withdrawal syndromes in patients who have been receiving such drugs chronically. They may also play a role in predisposing some patients to aspiration. And they are a frequent contributor to events occurring in patients with sleep apnea. They appear on Beers’ List or other lists of drugs potentially contraindicated in the elderly. In 2 columns (May 2012 “Safety of Hypnotic Drugs” and November 2012 “More on Safety of Sleep Meds”) we we also discussed the possible link between such drugs and mortality. In the latter column we also noted a study linking hypnotic use with hip fractures in nursing home patients (Berry 2012). This study found that nursing home residents taking the newer non-benzodiazepine hypnotics were 70% more likely to suffer hip fractures. In our March 2013 What’s New in the Patient Safety World column “Sedative/Hypnotics and Falls” we noted a study that showed zolpidem is associated with over a 4-fold increased risk of falls in inpatients (Kolla 2013). The number needed to harm (NNH) was calculated to be 55 and the risk appeared to be beyond that attributable to other medications.
Prescribing sleep meds, whether for inpatients or outpatients, is often done without much thought. All too often they are thought of as being relatively harmless. Knowing the downside is an important first step. But putting in place various system fixes (eg. removing them from standardized order sets, using clinical decision support tools, etc.) may play a more important role. Knowing and understanding how to promote good sleep hygiene is extremely important in helping patients avoid the need for such drugs in the first place.
Some of our previous columns on safety issues associated with sleep meds:
August 2009 “Bold Experiment: Hospitals Saying No to Sleep Meds”
March 23, 2010 “ISMP Guidelines for Standard Order Sets”
May 2012 “Safety of Hypnotic Drugs”
November 2012 “More on Safety of Sleep Meds”
March 2013 “Sedative/Hypnotics and Falls”
SAMHSA (Substance Abuse and Mental Health Services Administration), Center for Behavioral Health Statistics and Quality. (May 1, 2013). Emergency Department Visits for Adverse Reactions Involving the Insomnia Medication Zolpidem. Rockville, MD
FDA. FDA Drug Safety Communication: FDA approves new label changes and dosing for zolpidem products and a recommendation to avoid driving the day after using Ambien CR. May 14, 2013
Berry S, et al "Risk of hip fracture associated with non-benzodiazepine hypnotics in subgroups of nursing home residents" American Society for Bone and Mineral Research ASBMR 2012; Abstract 1056 as reported by Walsh N. Hip Fractures High with Newer Sleeping Pills. MedPage Today 2012; October 15, 2012
Kolla BP, Lovely JK, Mansukhani MP, Morgenthaler TI. Zolpidem Is Independently Associated With Increased Risk of Inpatient Falls. Journal of Hospital Medicine 2013; 8(1): 1-6
A new study from the researchers leading the highly successful Keystone initiative in Michigan to prevent catheter-associated UTI’s (CAUTI’s) has identified barriers to implementation of best practices to prevent CAUTI’s (Krein 2013). They used survey data and structured interviews in a sampling of participating hospitals to assess barriers encountered. Some of the barriers are well-known and anticipated but others are more surprising.
The least surprising, but most significant, barrier is lack of buy-in from physicians and nurses. Many physicians and nurses simply did not appreciate the invasive nature and potential seriousness of CAUTI’s. Convenience for nurses was also mentioned frequently. Some noted conflicting patient safety goals, often speculating that an indwelling catheter would keep patients from going to the bathroom, during which they might encounter a fall (ironically, falls might actually be more common in patients with indwelling catheters). Potential strategies to deal with these barriers include having a nurse “champion” and doing hourly rounds where attention to toileting activities is included. Hospitals have struggled with identifying physician “champions”, which can really help, but all noted that at least having some support from the medical staff was important.
A second barrier relates to ER insertion of urinary catheters. Many hospitals have had reasonable success at reducing urinary catheter insertion on their med-surg units and ICU’s. However, urinary catheters often get inserted in the OR or in the ER. The Krein paper notes many of the reasons that catheters get inserted in the ER, some not surprising but others somewhat unexpected. Those reasons not surprising were catheter insertion to get urine specimens and insertions for conveniences since bathroom facilities are often not readily accessible in ER’s. The busy nature of an ER is also a factor. But a somewhat surprising reason was the pereception that they were doing the nursing staff on the hospital floors a favor by inserting the catheters. The primary strategy here was working with the ER leadership to educate all staff on the importance of avoiding catheters that are not medically necessary. One factor they did not mention but that we see frequently is the lack of IT interoperability between the ER and the rest of the hospital. While some of our interventions have required a physician to order the catheter in CPOE and include an indication, those capabilities are often not present in the ER. A low-tech intervention might be simply having the physician specify the indication on paper before the catheter is removed from its packaging.
The surprising barrier was patient and family requests for urinary catheters. We would not have anticipated this and neither did the researchers. Educating the patient and family about all the adverse effects of catheters (see our May 2012 What’s New in the Patient Safety World column “Foley Catheter Hazards”), not just CAUTI’s, is the suggested intervention. It’s important for the physicians to understand these as well since many of the requests from patients and families to keep indwelling catheters go through the physician.
A companion study by the Michigan group (Saint 2013) looked at CAUTI rates in those hospitals participating in the Michigan Keystone Bladder Bundel Initiative compared to the rest of US hospitals. The Michigan hospitals were more likely to participate in collaboratives, more likely to use ultrasound bladder scanners, and more likely to use stop orders or nurse-initiated discontinuation. More frequent use of the preventive practices in Michigan hospitals led to a 25% reduction in CAUTI’s compared to only a 6% reduction over the same timeframe in the rest of the US.
And yet another recent study, presented as an abstract, showed that hospitalizations due to urinary catheters have been increasing over the past decade (Colli 2013). Analyzing national HCUP data, they found that hospitalizations due to indwelling urinary catheters increased from 11,742 in 2001 to 40,429 in 2010 and the corresponding national bill increased from $175 million to $1.3 billion for these. The majority of these patients had UTI’s but septicemia rates almost doubled.
Some of the same issues identified in acute hospitals by Krein et al. probably are also factors in continuation of catheter use after discharge, whether that discharge is to a nursing home or rehab facility or the patient’s home. Continuously asking whether the catheter is still necessary should be a regular part of the patient’s care. For example, some stroke patients may develop urinary retention acutely but in the majority that changes over time. It may be replaced by urinary incontinence as an uninhibited neurogenic bladder or reflex neurogenic bladder evolves but that incontinence is better managed by other methods (eg. condom catheters in males, pads in females, etc.). Even those who continue with urinary retention or develop detrusor-sphincter dyssynergia might be managed by alternative means (eg. intermittent catheterization). Clearly, individualization of management is needed but if you don’t ask whether the catheter is still needed no one will discontinue it.
Our other columns on urinary catheter-associated UTI’s:
Krein SL, Kowalski CP, Harrod M, Forman J, Saint S. Barriers to Reducing Urinary Catheter Use: A Qualitative Assessment of a Statewide Initiative. JAMA Intern Med 2013; 173(10): 881-886
Saint S, Greene MT, Kowalski CP, et al. Preventing Catheter-Associated Urinary Tract Infection in the United States. A National Comparative Study. JAMA Intern Med 2013; 173(10): 874-879
Colli J, Walls K, Dunn E, et al. Abstract 138: Hospitalizations due to indwelling urinary catheters, 2001-2010. American Urological Association (AUA) 2013 Annual Scientific Meeting. Abstract 138. Presented May 5, 2013
In the past 2-3 years we’ve done multiple columns (see list at the end of this column) highlighting some of the detrimental effects related to red blood cell transfusions and the trend toward more restrictive transfusion strategies in many different scenarios. Unnecessary transfusions have not only clinical untoward effects but add to health care costs.
Our focus, however, has always been on transfusions themselves. But even when actual transfusions are not given there may be costs and other potential consequences resulting from the blood ordering process. Ordering type-and-screen or type-and-crossmatch before surgical procedures creates a lot of work for blood banks and may result in delay in usage of those blood products for other patients or even wastage of blood products. Moreover, the workload burden on the blood bank may lead to delays in starting surgical cases or delays in responding to other emergencies.
It turns out that such blood ordering is part science and part guesswork and part habit. In fact, back in the 1970’s there was a Maximum Surgical Blood Order Schedule (MSBOS) developed that estimated how many units of blood should be ordered for each type of surgical procedure. But a lot has changed since the 1970’s! The number of different surgical procedures being performed has increased substantially and advances in surgical techniques and equipment have changed the likelihood that blood will be needed.
So researchers at Johns Hopkins (Frank 2013) analyzed data from their Anesthesia Information Management System (AIMS) on over 50,000 patients and over 1600 different surgical procedures at their institution for both blood ordering practices and actual transfusions. Not surprisingly they found that many patients not needing transfusions had either type-and-screen (32.7%) or type-and-crossmatch (9.5%) done. Also, about a third of patients who only needed type-and-screen had a type-and-crossmatch ordered. They calculated that a potential cost savings of $43,000 per year could be achieved at their institution by a new MSBOS which they developed. They used variables from the 1970’s MSBOS and data from their AIMS to develop an algorithm that could be used to improve blood ordering prior to surgery. They were able to group 135 categories of surgical procedures and assign them to one of 5 blood order groups.
Their algorithm could be used by other healthcare organizations to develop institution-specific, procedure-specific, and maybe even surgeon-specific blood ordering recommendations.
The next step will be to apply their MSBOS algorithm prospectively to see how it works in actual practice and to identify any unintended consequences of its use. But this is a very timely contribution to our evolving systems for managing blood products. Even if you don’t apply the algorithm prospectively in your organization, just doing the exercise on data from your own AIMS should be a worthwhile exercise that may identify practice patterns that might be improved. But the algorithm has the potential to improve efficiency in both the blood bank and the OR while reducing costs and even improving patient safety.
Also, in addition to those studies mentioned in our previous columns on the move toward more restrictive transfusion policies, there have been a few new papers worth reading. One study (Ferraris 2013) found an association between intraoperative blood transfusions and development of the systemic inflammatory response syndrome (SIRS). Mortality for patients who developed postoperative SIRS had mortality rates 13-fold higher than those who did not develop SIRS. A recent issue of The Lancet also had a series of excellent articles on blood product management and alternatives (Goodnough 2013, Spahn 2013, Williamson 2013).
Prior columns on potential detrimental effects related to red blood cell transfusions:
· March 2011 “Downside of Transfusions in Surgery”
· February 2012 “More Bad News on Transfusions”
· January 2012 “Need for New Transfusion Criteria?”
· April 2012 “New Transfusion Guidelines from the AABB”
· February 2013 “More Evidence Favoring Restriction of Transfusions”
Frank SM, Rothschild JA, Masear CG, et al. Optimizing Preoperative Blood Ordering with Data Acquired from an Anesthesia Information Management System. Anesthesiology 2013; 118(6): 1286-1297, June 2013
Ferraris VA, Ballert EQ, Mahan A. The relationship between intraoperative blood transfusion and postoperative systemic inflammatory response syndrome. The American Journal of Surgery 2013; 205(4): 457-465
Goodnough LT, Levy JH, Murphy MF. Concepts of blood transfusion in adults. The Lancet 2013; 381(9880): 1845-1854, 25 May 2013
Spahn DR, Goodnough LT. Alternatives to blood transfusion. The Lancet 2013; 381: (9880); 1855-1865, 25 May 2013
Williamson LM, Devine D. Challenges in the management of the blood supply. The Lancet 2013; 381(9880): 1866-1875, 25 May 2013
The “weekend effect” is a term used to refer to an increase in untoward events or suboptimal outcomes occurring in patients admitted to hospitals over the weekend. In some cases we use the term “after hours effect” since some of the same issues occur in patients admitted at night. We’ve discussed the numerous factors that may contribute to the “weekend effect” in our previous columns listed at the end of today’s column.
Various studies have demonstrated higher mortality rates for patients admitted on weekends with strokes, atrial fibrillation, diverticulosis surgery, a variety of other surgical procedures, head trauma, COPD, CHF, perinatal events, ICU admissions, ESRD, and other conditions. In fact, in our June 2011 What’s New in the Patient Safety World “Another Study on Dangers of Weekend Admissions” we noted a study (Ricciardi 2011) that found that mortality rates were higher for 15 of 26 major diagnostic categories when patients were admitted on weekends. Even after adjustment for comorbidities and a variety of other clinical and demographic characteristics there remained a significant increase in mortality, on the order of 10% higher for those admitted on weekends.
Now a new study (Aylin 2013) from the UK evaluated mortality for patients undergoing elective surgical procedures by day of the week and found the risk of death was 44% higher for surgery done on Fridays and 82% higher for those done on weekends compared to surgery done on Mondays. This occurred despite patients operated upon on Fridays and weekends having fewer comorbidities than those operated upon on Mondays.
A previous study done in the VA system in the US (Zare 2007) found that for patients admitted to regular hospital floors after non-emergent major surgery, mortality was increased if surgery is performed on Friday versus Monday through Wednesday. After adjusting for patient characteristics, odds ratio of 30-day mortality for operations on Fridays was 17% higher than for operations on Mondays through Wednesdays.
The perioperative period is one of greatest vulnerability for most patients undergoing surgery. So it is not surprising that we might expect more complications on the several days following surgery, whether elective or emergent. Since most of the postoperative care for patients having surgery on Fridays will actually occur over the weekend, it’s logical to attribute this Friday phenomenon to “the weekend effect” (but see below for other key considerations).
Our healthcare systems clearly do not deliver uniform care 24x7. The differences between the hospital during weekday daytime hours and the hospital at night and on weekends is striking. Staffing patterns (both in terms of volume and experience) are the most obvious difference but there are many others as well. Many diagnostic tests are not as readily available during these times. Physician and consultant availability may be different and cross-coverage by physicians who lack detailed knowledge about individual patients is common. You also see more verbal orders, which of course are error-prone, at night and on weekends.
But often it is the difference in non-clinical staffing that is a root cause. Our December 15, 2009 Patient Safety Tip of the Week “The Weekend Effect” discussed how adding non-clinical administrative tasks to already overburdened nursing staff on weekends may be detrimental to patient care. Just do rounds on one of your med/surg floors or ICU’s on a weekend. You’ll see nurses answering phones all day long, causing interruptions in some attention-critical nursing activities. Calls from radiology and the lab that might go directly to physicians now go first to the nurse on the floor, who then has to try to track down the physician. They end up filing lab and radiology reports or faxing medication orders down to pharmacy, activities often done by clerical staff during daytime hours. Even in those facilities that have CPOE, nurses off-hours often end up entering those orders into the computer because the physicians are off-site and are phoning in verbal orders. You’ll also see nurses giving directions to the increased numbers of visitors typically seen on weekends. They even end up doing some housekeeping chores. All of these interruptions and distractions obviously interfere with nurses’ ability to attend to their clinically important tasks (see our Patient Safety Tips of the Week for August 25, 2009 “ ” and May 4, 2010 “More on the Impact of Interruptions”).
While staffing levels have attracted the most attention in attempt to explain “the weekend effect”, there may be other factors that are important. Consecutive days worked may also play a role and this could apply to surgeons as well as all other members of the OR team. Our November 9, 2010 Patient Safety Tip of the Week “study on shift workers in fields other than healthcare ( ” cited a Folkard 2003) which showed that the risk of incidents increased each consecutive day worked. For example, on average for night shifts risk was 6% higher on the second night, 17% higher on the third night, and 36% higher on the fourth night. While most people reading that article focus on those night shift statistics, the corresponding risks for morning/day shifts were 2%, 7% and 17%. So it is clear that risks in most industries increase with consecutive days worked. In fact, in the Aylin study mortality increased in a linear fashion by a factor of 1.09 for each day beyond Monday. So it is hard to ignore the parallel between the consecutive days worked statistics and the pattern of mortality seen by day of the week.
As noted in the editorial accompanying the Aylin study (Kwan 2013) maybe we need to think twice about the adage “thank goodness it’s Friday”! Guess what! If we ever need elective surgery, we aren’t going to have it on a Friday even if that’s the most convenient day for us!
Some of our previous columns on the “weekend effect”:
Ricciardi R, Roberts PL, Read TE, et al. Mortality Rate After Nonelective Hospital Admission. Arch Surg. 2011; 146(5): 545-551
Aylin P, Alexandrescu R, Jen MH, et al. Day of week of procedure and 30 day mortality for elective surgery: retrospective analysis of hospital episode statistics. BMJ 2013; 346: f2424
Zare MM, Itani KMF, Schifftner TL, Henderson WG, Khuri SF. Mortality after nonemergent major surgery performed on Friday versus Monday through Wednesday. Ann Surg 2007; 246: 866-74
Folkard S, Tucker P. Shift work, safety and productivity. Occupational Medicine 2003; 53: 95-101
Kwan JL, Bell CM. Should we rethink the scheduling of elective surgery at the weekend?
BMJ 2013; 346: f3353 (Published 28 May 2013)