Clinical Objectives
- List the causes of prolonged apnea in
the operating room
- Describe the steps in management of
apnea in the operating room
Patient Safety Objectives
- State the prevalence of medication
errors
- List the causes of wrong drug
administration in the operating room
- Describe the system checks available to
prevent medication errors in the operating room
A 15-year-old boy underwent elective right
knee arthroscopy and debridement under general anesthesia with a
laryngeal mask airway (LMA). He was otherwise healthy with no
allergies to medications. After uneventful induction of anesthesia,
the surgeons requested antibiotic prophylaxis with cefazolin 1
gram, which the anesthesiology team administered. Just before the
surgical incision was made, 50 mcg of Fentanyl was administered.
About 2 minutes later, spontaneous respirations slowed, and the
patient became apneic. The surgeon and anesthesiologist assumed the
patient’s apnea was due to opiate sensitivity and assisted
ventilation by hand for 30 minutes. However, despite a rise in the
end-tidal CO2 to 70mm Hg, spontaneous respirations did not
return.
Apnea during anesthesia has several etiologies,
including anesthetic agents themselves, as well as opiates,
barbiturates, or benzodiazepines, and hypocarbia-induced
respiratory depression. Prolonged apnea occurs more often in
hyperventilated patients; neonates; elderly patients; patients with
compromised renal, pulmonary, or hepatic function; hypothermic and
acidotic patients; patients receiving neuromuscular blockade,
aminoglycosides, or intravenous magnesium; and patients with
neurological impairment or injury.
Assuming this patient is healthy, normothermic,
and not acidotic or hypocarbic, and assuming he did not receive
neuroaxial anesthetic blockade (such as spinal or epidural regional
anesthesia), I would be concerned that he received an unplanned
drug due to a syringe or an ampoule swap.(Table
1) While maintaining cardiovascular and respiratory functions,
clinicians should attempt to ascertain whether a wrong drug was
administered, and if so, which drug.(Table 2)
(1) The most
common drugs that may lead to apnea include muscle relaxants or
highly potent opiates (such as Sufentanil, which is ten times as
potent as fentanyl). Alternatively, the patient may have a
previously unrecognized metabolic disorder such as a neuromuscular
disease (ie, myasthenia gravis) or a structural abnormality (ie,
stroke or embolism) that needs to be evaluated.
Treatment of medication-induced respiratory
depression varies by cause. When respiration is depressed by
opiates, as evidenced by miotic, unresponsive pupils, naloxone
(Narcan) in 0.04 mg increments may be titrated to reverse the
condition. In the case of persistent peripheral muscle blockade,
typically due to residual muscle relaxants, reversal with
neostigmine is initiated. Other interventions include
discontinuation of anesthetics, determination of arterial blood
gases, and appropriate adjustment of ventilation.(Table 3)
Because the apneic episode lasted longer than
30 minutes, the anesthesia team began to question their initial
assumption that the apnea was due to opiate sensitivity. They had
obtained the cefazolin from the medication drawer of the anesthesia
cart. The anesthesia team examined the drawer and found vials of
cefazolin and vecuronium (a long-acting paralytic agent) in
adjacent medication slots. The vials were of the same size and
shape, with similar red plastic caps.(Figure
1) The team realized that the patient had received vecuronium
10 mg, not cefazolin 1 g, and that the observed apnea was therefore
due to unrecognized muscle relaxation.
There is no accurate measure of the morbidity and
mortality associated with anesthesia. It has been estimated that
between 2000 and 10,000 patients die each year from causes at least
partially related to anesthesia, but those estimates are based on
circumstantial data and include all patients regardless of age or
physical status.(2) A recent
study in the United Kingdom found that only 1 patient in 185,000
died solely as result of anesthesia, although 1 in 1351 deaths was
in part related to anesthesia.(3) An estimated
44,000-98,000 Americans die in hospitals each year as a result of
preventable medical errors.(4) Medication
errors were the number one cause of adverse and preventable
patient events, leading to more than 7000 deaths
annually.(4)
The prevalence of medication errors in the
operating room is not accurately known, although it is probably
similar to that of medication errors in the hospital. Bates and
colleagues have shown that 6.5% of admitted patients suffered an
adverse
drug event.(5) Of these
events, 28% were due to errors, and an additional 5.5% involved
near misses
caught due to interception of the error. In the Harvard Medical
Practice Study, adverse drug events accounted for 19.4% of all
disabling adverse events, 45% of those events were caused by
errors.(6) In a large
insurer’s study, injuries due to drugs were the most frequent
cause of procedure-related malpractice claims.(7)
Wrong medication administration in the operating
room is due to failure to label syringes, incorrect matching of
labels on syringes and drug ampoules, failure to read the label on
the vial/ampoule, misuse of decimal points and zeroes, and
inappropriate abbreviations. What happened to this patient
illustrates an example of faulty drug identity checking, where two
drugs were packaged in similar vials, so that one was easily
mistaken for the other. Poor system design also makes errors
difficult to intercept before injury occurs. Leape and colleagues
discovered that failures at the system level were the real culprits
in more than three-fourths of adverse drug events.(8) Reason and
colleagues suggested that some complex healthcare systems are more
vulnerable and therefore more likely to experience adverse
events.(9)
Documenting errors at the administration stage is
difficult, because it requires direct observations and reliable,
robust near-miss and adverse-event reporting systems. Currie and
colleagues found 144 incidents related to drugs, of which 58 were
related to syringe or drug swaps,(10) among the
first 2000 incidents of the Australian Incident Monitoring System.
Of those 58 events, 71% involved muscle relaxants. Implementing a
red syringe color change for all Succinylcholine drug
administration in Australia has helped to reduce drug and syringe
swap by 70%.(11) A large,
retrospective study of anesthesiologists’ self-reported
incidents found that of a total of 1089 incidents, 71 were related
to either syringe or drug ampoule swap (7%).(12)
Leape and colleagues found that 40 of 334 errors (12%) at the stage
of drug ordering and delivery were due to imperfect dose and
identify checking.(8) Studies in
intensive care units have produced similar results.(13)
Administrative medication errors in the operating
room and intensive care unit are believed to be more common in
unfamiliar settings, when drug packaging or ampoules have changed,
when similarly appearing ampoules are stored close together in the
medication carts, when syringes are prepared by other personnel,
when hand written labels are used, and when lighting conditions are
poor.(14) There is an
exponential relationship between the number of drugs administered
to a patient and the prevalence of adverse drug events.(15)
Although there is no excuse for failing to read
medication and syringe labels, the occasional failure to do so
represents an expected “slip,” more likely to occur
with fatigue, distraction, or other causes of momentary lapses in
concentration and failures in automatic behaviors.(16,17,20) Not
until recently did the pharmaceutical industry realize the
importance of packaging medications to easily facilitate rapid
identification of and discrimination between potent drugs used in
operating rooms. For years muscle relaxants such as pancuronium
vials were very similar to those of heparin. Some manufacturers
continue to package ephedrine in ampoules similar to those of
oxytocin and epinephrine. This problem also occurs with different
doses of the same drug--the vials for at least three concentrations
of atropine sulfate from one manufacturer are similar. This results
in inadvertent over- and under-dosing.
Any medication drawn into a syringe for later use
should be labeled immediately. Unlabeled and incorrectly labeled
syringes invite errors in drug administration and dosing and should
be discarded. Routine use of approved, commercial color-coded
labels may reduce these errors. The labels should conform to the
standards of the American Society for Testing and Materials
(ASTM).(18)
A cluttered and disorganized workspace also
predisposes to medication errors and searches that can delay
administration of emergency medications. All anesthesia and
resuscitation medication carts should be standardized,(Figure 2) by
applying a systematic method for stocking new and discarding
outdated medications.
Hand ventilation was continued to achieve
normocapnia until the muscle relaxant had dissipated and
neostigmine could be administered. After reversal of muscle
relaxation, apnea resolved, anesthesia was discontinued, and the
patient was transported safely to the post-operative care unit,
where he recovered fully and was discharged.
To understand the causes of errors, we must
examine what happened, what was the root cause,
and what were the underlying system failures.(19)
In a systems analysis, people are viewed as an important safety
resource, not only a source of errors. Designing robust transparent
systems, with built in feedback control strategies is important
given human flexibility and fallibility. This was a case of
unintentional administration of a paralytic agent in place of an
antibiotic due to similar packaging. System checks that could be
implemented here to avoid inadvertent drug swaps include
color-coded labeling and reorganization of the anesthesia
cart.(Table 4) Training
all healthcare professions in the Six Right’s—patient,
drug, dose, route, time, concentration—is critical to
effective and safe medication administration. Recognizing
environmental factors that predispose and distract clinicians is
paramount. These include: noise, interruptions, fatigue and lack of
adequate rest, poor lighting, and poor information systems.
Barcoding point-of-care systems (BPOC) are the
main technology interventions to prevent medical and blood
transfusion errors. The Institute of Medicine report noted that
barcoding “is an effective remedy” for medication
errors, “a simple way to ensure that the identity and dose of
the drug are as prescribed, that it is being given to the right
patient, and that all of the steps in the dispensing and
administration processes are checked for timeliness and
accuracy.” BPOC uses bedside computers that interact with a
radio wave-controlled wireless communication system. Changes in
medications and other patient information are instantly
communicated from hospital information systems to the bedside unit,
notifying nurses of changes. BPOC systems enable managers to
monitor the medications given to patients and help hospitals
identify opportunities for improvements in their
medication-administration procedures.
Whenever medications are administered, robust
identification systems must be present to avoid inadvertent wrong
drug administration.
Take-Home Points
- Medication errors are the number one
cause of preventable adverse events, including death.
- Causes of wrong drug administration
include failure to label medications, mislabeling of syringe or
ampoules, or failure to confirm identification of the medication by
reading label carefully.
- To reduce drug administration errors in
the OR, label syringes carefully with color-coded, pre-printed
labels that conform to ASTM standards; use
“ready-to-use” easily identified syringes to administer
emergency drugs; standardize location of medications on the
anesthesia cart; and always review the Six Right’s (patient,
drug, dose, route, time, concentration).
- System checks should be designed into
the medication administration process to prevent or reduce chances
of inadvertent drug/vial swap.
- Physician drug order entry and barcoding
systems can reduce the number of adverse drug events.
Paul Barach, MD,
MPH
University of Chicago
Faculty Disclosure: Dr. Barach has
declared that neither he, nor any immediate member of his family,
has a financial arrangement or other relationship with the
manufacturers of any commercial products discussed in this
continuing medical education activity. In addition, his commentary
does not include information regarding investigational or off-label
use of pharmaceutical products or medical devices.
1. Gravenstein Nick, ed. Manual Of Complications
During Anesthesia. Lippincott, Philadelphia; 1991.
2. Cooper JB. Toward prevention of anesthetic
mishaps. Int Anesthesiology Clin. 1984;22:167-183.
[ go to pubmed ]
3. Lunn JN, Devlin HB. Lessons from the
confidential enquiry into perioperative deaths in three NHS
regions. Lancet. 1987;12:1384-1386.
[ go to pubmed ]
4. Kohn LT, Corrigan JM Donaldson MS, eds. To Err
is Human: Building a Safer Health System. Institute of Medicine.
Committee on Quality of Health Care in America. Washington, DC:
National Academy Press; 1999.
5. Bates DW, Cullen D, Laird N, et al. Incidence
of adverse drug events and potential adverse drug events:
implications for prevention. JAMA. 1995;274:29-34.
[ go to pubmed ]
6. Leape LL, Brennan TA, Laird N, et al. The
nature of adverse events in hospitalized patients: results of the
Harvard Medical Practice Study II. N Engl J Med.
1991;324:377-384.
[ go to pubmed ]
7. National Association of Insurance
Commissioners. Medical Malpractice Closed Claims, 1975-1978.
Brookfield, Wis; National Association of Insurance Commissioners;
1980.
8. Leape LL, Bates DW, Cullen DJ, Cooper J,
Demonaco HJ, Gallivan T, et al. Systems analysis of adverse drug
events. JAMA. 1995;274:35-43.
[ go to pubmed ]
9. Reason JT, Carthey J, and de Leval, MR.
Diagnosing “Vulnerable System Syndrome”: An Essential
Prerequisite to Effective Risk Management. Qual Health Care.
2001;10:ii21-ii25.
[ go to pubmed ]
10. Currie M, Mackay P, Morgan C, et al. The
“wrong drug” problem in anesthesia: an analysis of 2000
incident reports. Anaesth Intensive Care. 1993;21:596-601.
[ go to pubmed ]
11. Russell WJ. Getting in the red: a strategic
step for safety. Qual Saf Health Care. 2002;11:107.
[ go to pubmed ]
12. Cooper JB, Newbower RS, Kitz RJ. An analysis
of major errors and equipment failures in anesthesia management:
Considerations for prevention and detection. Anesthesiology.
1984;60:34-42.
[ go to pubmed ]
13. Tissot E. Cornettte C, Demoly P. et al.
Medication errors at the administration stage in an intensive care
unit. Intensive Care Med. 1999;25:353-359.
[ go to pubmed ]
14. Gaba DM, Maxwell M, DeAnda A. Anesthetic
mishaps: breaking the chain of accident evolution. Anesthesiology.
1987;66:670-676.
[ go to pubmed ]
15. Smith JW, Seidl LG, Cluff LE. Studies on
epidemiology of adverse drug reactions. V. Clinical factors
influencing susceptibility. Ann Intern Med. 1966;65:629-640.
[ go to pubmed ]
16. Reason J. A preliminary classification of
mistakes. In: Rasumussen J, Duncan K, Lelpat J, eds. New Technology
And Human Error. Chiseter, Wiley;1987:15-22.
17. Rasmussen J. Information processing and
human-machine interaction: an approach to cognitive engineering.
New York: Elsevier;1986:149-151.
18. American Society for Testing and Materials.
Standard specification for user applied drug labels in
anesthesiology. American Society for Testing and Materials.
D477494,1995.
19. Gaba DM, Fish K, Howard S, eds. Crisis
Management in Anesthesiology. New York, NY: Churchill Livingston;
1994.
20. Bates, DW. Unexpected hypoglycemia in a
critically ill patient. Ann Intern Med. 2002;137:110-116.
[ go to pubmed ]
Table 1. When to Suspect Wrong Drug
Administration in the Operating Room
Unusual response or lack of response to
drug administration: pounding heart, mental status changes, apnea,
muscle weakness, and visual disturbances
|
Extreme or unexpected increase or
decrease in blood pressure or heart rate
|
Unexpected or persistent muscle
relaxation
|
Unexpected change, or lack of change, in
level of consciousness
|
Incorrect ampoule found to be open in
work area
|
Table 2. Checklist: Steps to Determine Drug
Administered
Check the syringes and ampoules used
during the case
|
Check to see if low volume unexpectedly
remains in syringe
|
Inspect open ampoules
|
Impound the “Sharps”
container to allow inspection of ampoules and syringes at later
time
|
Consider drawing blood levels to
ascertain drug given
|
Table 3. Clinical Management of Apnea
- Ensure adequate oxygenation and
ventilation
- If the error in drug administration is
recognized immediately after injection:
- Stop the IV carrying the drug
- Attempt to aspirate or drain the IV
tubing to point of injection
- If there is blood pressure cuff on arm
of IV, inflate to slow down entry of drug to central
circulation
- Maintain normocarbia or slight
hypercarbia
- Increase O2 flow to breathing circuit to
enhance elimination of inhalation anesthetics
- Check neuromuscular function with nerve
stimulator
- If residual blockade is present:
- Give reversal medication to max of
neostigmine dose of 70 mcg/kg along with glycopyrrolate up to 1 mg
to reverse blockade
- Reassure the patient and continue
short-acting sedation
- Consider potential synergistic effects
of muscle relaxants and aminoglycosides—if so give 1 gm
calcium chloride to promote reversal of neuromuscular blockade
- Review the doses of medication
administered and check for syringe or ampoule swap of opiates,
hypnotics, muscle relaxants, anticholinergics
- Consider reversal of specific drugs such
as opiates (check pupils), benzodiazepines, anticholinergics
- Send blood samples for ABG and serum
electrolyte levels
- Conduct a neurological examination to
exclude focal CNS injury as cause of failure to breathe
|
Table 4. System Checks to Prevent Wrong Drug
Administration
Check for correct patient, drug name,
concentration, dose, route, time
|
Use drug labels that conform to ASTM
standards
|
Label syringes carefully—use
preprinted color-coded adhesive labels
|
For emergency drugs, use “ready to
use” syringes that are prepared according to ASTM
standards
|
Standardize location of medications
|
Discard unlabeled vials, syringes
|