Introduction
Introduction
The increasing invasiveness of endoscopic examinations and interventions means
that adequate sedation and appropriate patient monitoring are required. Overall,
endoscopic interventions in the gastrointestinal tract are low risk, provided
that they are performed in sufficient numbers by experienced personnel [1]. The risk of the examination or intervention depends primarily on the invasiveness
and technical complexity of the procedure, but also on the patient’s individual
risk profile and the specific side-effect profile of the sedatives or anesthetics
used. The overall rate of serious complications in gastroenterological examinations
and interventions is between 1 in 1000 and 1 in 7500 [2].
The quality of procedures and, in turn, patient safety depend greatly on precise
and careful risk estimation before, during, and after the procedure. Information
provided to patients on the planned procedure should not only be timely and cover
the invasiveness of the procedure - it should include information not only on
the risks of the procedure itself but also on the specific risks of sedation.
Risk factors
Risk factors
For the evaluation of the entire risk of a procedure, a clear distinction must
be made between general risk (patient-specific factors), risks inherent in the
procedure itself (for example pancreatitis after endoscopic retrograde cholangiopancreatography
[ERCP], perforation and/or bleeding after papillotomy, and bleeding after endoscopic
muco-resection), and the risks associated with sedation.
The general risk for upper gastrointestinal endoscopy depends mainly on the presence
of cardiorespiratory disease and on the general health of the patient [3]
[4]. In this context, the complication rate increases very considerably with the
length of the procedure.
Before every procedure, patient-specific risk factors must be evaluated. This
is best done on the basis of the classification of the American Society of Anesthesiologists
(ASA) ([Table 1]). Before every procedure, in the context of obtaining the patient’s informed
consent, the patient’s history and medical reports must be obtained. The spectrum
of clinical and preparatory studies to be ordered increases with increasing risk
(see [Table 2]).
Table 1 The American Society of Anesthesiologists (ASA) classification of anesthetic risk
according to general health status
| ASA class |
Clinical profile |
| I |
Healthy patient |
| II |
Mild illness without physical limitations |
| III |
Serious illness with physical limitations |
| IV |
Serious illness with threat to life |
| V |
Death expected within 24 hours |
Table 2 Patient-specific risk factors
| ASA class III/IV |
| Decompensated heart failure, NYHA class III/IV |
| Coronary heart disease |
| Valve disease/replacement |
| Hepatic and renal failure |
| Pulmonary disease |
| Clotting disorders |
| ASA, American Society of Anesthesiologists; NYHA, New York Heart Association.
|
Sedation
Sedation
Different degrees of sedation have been defined: “sedation” is understood to mean
a clouding of consciousness; “deep sedation” is loss of consciousness with retention
of spontaneous respiration and protective reflexes; and “general anesthesia”
is defined as loss of consciousness, spontaneous respiration, and protective reflexes,
attributable to the effects of substances acting on the central nervous system.
The increasing technical complexity of endoscopic procedures increasingly commonly
requires deep sedation of the patient as well as adequate analgesia. Even for
purely diagnostic endoscopy, sedation can be advantageous, not only for the patient
but also in terms of achievement of higher-quality procedures. The following list
summarizes the endoscopic procedures which most often require the use of sedation
or deep sedation:
-
Interventional endoscopy in the upper gastrointestinal tract (hemostasis; treatment
of varices with ligation, sclerotherapy, or tissue-adhesive therapy; dilation
procedures; implantation of prostheses; endoscopic mucosal resection; and disobliteration
procedures);
-
diagnostic and interventional endosonography;
-
percutaneous endoscopic gastrotomy;
-
colonoscopy with difficult and/or multiple polypectomy or with endoscopic mucosal
resection;
-
ERCP with interventions involving the bile ducts (endoscopic papillotomy, mechanical
lithotripsy, stone removal, implantation of prostheses) and the pancreatic ducts
(selective sphincterotomy, stone removal, dilation, implantation of prostheses).
With purely diagnostic gastroscopy, the use of sedatives involves a slightly higher
rate of complications [5]
[6], but patient acceptance is significantly higher than without sedation.
Benzodiazepines are the most commonly used sedatives; opiates have been used much
less frequently in recent years due to the high rate of respiratory complications.
Midozalam is a sedative that was specially developed for short procedures [7]; besides sedation, it provides antegrade amnesia, a desirable effect that means
that the unpleasant sensations perceived by the patient during endoscopy tend
to recede. Its use does, however, require that special attention is paid to the
outpatients who receive it, especially with regard to the provision of patient
information and patient handling after endoscopy (see below).
The increasing complexity of endoscopic procedures in recent years has necessitated
the use of centrally acting anesthetics. Propofol is a particularly popular choice
for induction and maintenance of deep sedation. It is a highly lipophilic anesthetic
with fast distribution (2 - 4 minutes) and fast elimination (half-life 30
- 60 minutes). The therapeutic spectrum of propofol, however, is much narrower
than that of midazolam, so that careful monitoring to differentiate between sedation,
deep sedation, and narcosis is much more demanding as far as personnel and equipment
are concerned.
The safe use of sedatives and anesthetics
The safe use of sedatives and anesthetics
The patient’s safety must take the highest priority in all considerations surrounding
the use of a medication.
A meta-analysis of randomized studies published to date comparing propofol and
conventional sedatives did not show a higher complication rate for propofol, but
it did reveal that recovery after propofol was significantly faster and also a
trend toward a lower incidence of hypoxia and hypotension (though this finding
was not statistically significant) [8]. This leads to the conclusion that propofol is at least as safe as the generally
accepted conventional sedation with benzodiazepine derivatives or midazolam.
Although anesthesiologists the world over have repeatedly stressed that only they
are in a position to use an anesthetic such as propofol safely, there are data
indicating that this drug can be used safely by nonanesthesiologists [9]
[10]. In the earlier of these two studies, propofol was administered over a period
of 5 years for 28 472 endoscopic procedures, either by general medical staff or
by anesthesiologists [9]: there were 185 complications related to sedation (0.64 %) but no deaths. There
were no specific differences between the two types of physicians with regard to
the figures for complications. In the 2003 study [10], the sedation-related complication rate did not increase when propofol was
administered to 819 patients (ASA I - IV) by gastroenterologists.
There are also well-documented data showing that this regime is safe when propofol
is administered by specially trained nursing personnel [11]
[12]
[13]
[18]. No disadvantageous effects were seen when propofol was administered by specially
trained nursing personnel to 9152 patients undergoing outpatient endoscopy. A
further prospective study covering 27 500 documented cases did not show any negative
effect on the complication rate when propofol was given by nurses. In one controlled
study, this was shown to be true even for high-risk patients (ASA III/IV)
[14].
These data are taken into consideration in the revised “Practice guidelines for
sedation and analgesia by non-anesthesiologists”, published by the American Society
of Anesthesiologists in 2002 [17]. The relevant recommendation reads, “An additional person, specially entrusted
with this task, must be present, who is qualified to safely administer and monitor
the sedation, and to take appropriate emergency measures …”
One prerequisite for the safe use of sedatives and anesthetics is safe venous
access. Apart from the administration of the sedative agent, another important
safety factor when considering the use of propofol is the provision of adequate
monitoring during deep sedation and after completion of the endoscopy or endoscopic
intervention.
It is obvious that the endoscopist cannot be expected to simultaneously perform
the endoscopic procedure, which may be very complex; administer an anesthetic
with a narrow therapeutic spectrum; and monitor the patient in a dimly lit endoscopy
unit. There must be an additional person present in the endoscopy suite whose
sole responsibility is to administer the sedative or anesthetic and to monitor
the patient during the endoscopy. According to published data, this person can
be an anesthesiologist, a specially trained physician, or a specially trained
member of the nursing staff. The specially trained nurses must be familiar with
the agent administered, be able to maintain respiration when complications occur
or during the transition from deep sedation to general anesthesia, and be able
to handle cardiovascular side effects or complications caused by the agent
administered.
In all cases, there should be complete, clear, and understandable documentation
of all measures taken when a sedative or anesthetic is administered.
Monitoring
Monitoring
With deeper sedation, it is absolutely essential to provide for suitable monitoring
during endoscopy or endoscopic interventions. Monitoring of the patient is primarily
the task of the designated staff member (medical or nursing personnel); technical
equipment is only supplementary.
Routine endoscopy with conventional sedation calls for continuous, noninvasive
oxygen monitoring (pulse oximetry), though there have been no controlled studies
proving that cardiorespiratory complications are reduced when this measure is
employed [15]. This would be hard to prove in view of the low rate of complications attributable
to endoscopy and sedation and consequently the very large number of patients that
would be required in any study.
Routine administration of oxygen is also controversial. It has been shown that
the average oxygen saturation decreases, but not that severe hypoxia can be effectively
prevented [16]. The benefit of continuous, noninvasive blood-pressure monitoring under conventional
sedation has also not been proved.
When propofol or deep sedation is used, equipment must be available for mask respiration
and endotracheal intubation; the medications for resuscitation should be at hand
and there should be oxygen and vacuum connections. With this regime, apart from
the continuous administration of oxygen, there is no question of the value of
continuous, noninvasive blood-pressure measurement, because hypotension as a specific
side effect of propofol that can and should be recognized promptly. Electrocardiographic
monitoring should also be available.
When patients with known risk factors undergo endoscopy or endoscopic interventions
under deep sedation who might require endotracheal intubation (see [Table 3]), the presence of an anesthesiologist might be desirable, depending on the intubation
experience of the endoscopy team.
Table 3 Patients in whom the physician might anticipate a ”difficult” endotracheal intubation
(according to the American Society of Anesthesiologists)
| Patients with previous complications related to sedation or anesthesia |
| Patients with stridor, known sleep apnea, known tracheomalacia, or tracheal
stenosis |
| Patients with congenital deformities of the nasopharynx (e. g. trisomy 21,
Pierre Robin sequence) |
| Patients with relevant dental, oral, or jaw malformations |
| Patients with congenital or acquired conditions of the cervical spine |
In all cases there should be complete, clear, and understandable documentation
of all parameters recorded during the entire endoscopic procedure.
Postendoscopic surveillance
Postendoscopic surveillance
The sedative effect of the agents used persists far beyond the end of the endoscopy
or endoscopic intervention. Surveillance will depend on which agents have been
used and the depth of sedation, and should be continued until the patient has
completely recovered consciousness. There should be a suitably equipped and staffed
recovery room. Pulse oximetry should be available, as should electrocardiography
and noninvasive blood-pressure monitoring (for high-risk patients) after administration
of propofol.
Outpatients should only leave the recovery room when they have fully regained
consciousness. The patient will have been informed in advance that for the 24
hours following sedation he or she should avoid business transactions, operating
motor vehicles, and performing difficult or dangerous tasks; nonetheless, these
instructions should be repeated before the patient is discharged.
Here as well there should be clear and careful documentation of all parameters
recorded and all measures taken.
Summary
Summary
-
Patient safety has the highest priority in the performance of endoscopy or endoscopic
interventions and in the administration of accompanying measures such as sedation.
This applies above all to the allocation of time, space, personnel, and equipment
in the endoscopy suite.
-
Every procedure must be preceded by an individual risk classification assessment.
The result must be recorded in writing (in the context of the information given
to the patient).
-
Good venous access is a prerequisite.
-
The administration of sedatives or anesthetics must, above all, take into consideration
the depth of sedation. This in turn determines the extent of monitoring. The
medication and co-medications used (including trade names and dosage) must be
documented, either in the endoscopy report or in a separate record.
-
There must always be an individual present who is responsible for the administration
of sedatives or anesthetics. Depending on the degree of sedation on the one
hand and on the presence of risk factors that could lead to a requirement for
intubation on the other, this individual can be a specially trained assistant
or nurse, a member of the general medical staff, or an anesthesiologist.
-
This individual is responsible for monitoring during the endoscopic procedure.
The patient’s recovery must be monitored in a specially equipped unit and be
briefly documented by the responsible staff there.
-
Special attention must to given to precise and detailed documentation of all
steps of the process described (risk stratification, patient information, medication,
procedural records).
Competing interests: None
