Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_827_Библиотеки_им_академика_М_И_Перельмана
.pdf
https://t.me/med1917
Chapter 25
https://t.me/med1917
Choosing the Best Anesthetic Regimen
Sheila R. Barnett
Introduction
Why Is Anesthesia a Particular Concern
in Elderly Patients?
The administration of anesthesia to a geriatric patient requires
meticulous attention to detail and a clear understanding of
the impact of aging on organ reserve and function. Older surgical patients present for surgery with complicated medical
histories, limited physiologic reserve, and frequently unpredictable responses to anesthetic agents [1, 2]. In general,
elderly frail patients with underlying chronic disease can be
less tolerant of brief episodes of hemodynamic instability
such as hypotension or desaturation that may not be preventable during the course of a surgery. While these events may
be insignificant in a young patient and in the frail elder, they
may lead to serious consequences, such as cardiac ischemia
and arrhythmias [3, 4]. This chapter reviews the basic anesthetic concepts and discusses the impact of aging on the
choice of anesthesia.
choose the regimen that is most appropriate for the patient
and the surgeon. In many instances, the choice of the anesthesia is limited, for example, the elderly patient presenting
with a perforated bowel and evidence of hemodynamic
instability will require a general anesthesia with endotracheal intubation. In this example, there are no viable alternatives for the anesthetic type. However, even in this case
and other similar cases in which the choice of anesthetic
type is limited, the risks and benefits of the individual medications administered, the monitoring requirements, the
positioning during the surgery, the duration of the surgery,
and the post operative recovery plan will require thorough
consideration [5]. For the older patient, the anesthesiologist
must be prepared to tailor the anesthetic carefully to provide age appropriate care.
Using the case below, the challenges encountered by a
“geriatric” anesthesiologist will be illustrated through
a discussion of the case of Mr. Smith.
General Considerations for the Elderly Patient
Choosing the Anesthetic Regimen
Regardless of the age of the patient, the choice of anesthesia is influenced by several factors: the patient’s medical
and psychological condition, the type and duration of the
procedure or surgery, and the requirements of the surgery
itself. The anesthesiologist is ultimately responsible to
S.R. Barnett (*)
Department of Anesthesiology, Beth Israel Deaconess Medical Center,
Harvard Medical School, Boston, MA, USA
e-mail: sbarnett@bidmc.harvard.edu
R.A. Rosenthal et al. (eds.), Principles and Practice of Geriatric Surgery,
DOI 10.1007/978-1-4419-6999-6_25, © Springer Science+Business Media, LLC 2011
Mortality and risk of an adverse event associated with
surgery increase with advanced age [4, 6–9]. This is due to
multiple factors including age related reductions in physiologic reserve, the increase in comorbid conditions, and the
magnitude and type of the surgery itself. Complex emergency cases in the elderly carry the highest mortality with a
suggested threefold increase in mortality. The risk of cardiac complications in geriatric patients following emergency surgery increases three to five times, and the chance
of postoperative intubation and ventilation is five times that
of a young patient undergoing a major emergency surgery.
The magnitude and size of surgery are relevant: thoracotomy mortality in patients over the age of 70 years has been
reported as high as 17% and emergency abdominal surgery
in patients over the age of 80 years carries a mortality rate
of 10–25%.
305
306 S.R. Barnett
https://t.me/med1917
CASE STUDY: PART 1
Mr. Smith is a 85-year-old male presenting with new
right upper quadrant pain. He is scheduled for an upper
endoscopy and ERCP with a possible biliary dilation.
Past medical history includes known gallstones, chronic
lower back pain, Parkinson’s disease, and hypertension.
Prior surgery includes brain surgery for his tremor
5 years ago, and a lumbar discectomy 15 years ago.
He consults his primary care doctor regularly and a
neurologist for his Parkinson’s every 3 months. In the
past 12 months, he has had an EKG, which showed left
ventricular hypertrophy and nonspecific ST changes; he
has not had any further cardiac testing. His medications
include a beta blocker, levodopa, intermittent ibuprofen
and he has a prescription for acetaminophen with
codeine but as per his wife he rarely takes any pain medication. Mr. Smith lives with his wife, in the past
12 months he has had increasingly difficulty with ambulation and has fallen several times. His appearance and
speech are consistent with severe Parkinson’s. Depending
on the results of the ERCP, he may or may not require
either a laparoscopic cholecystectomy or a more extensive biliary surgery.
Mr. Smith has several medical issues that will challenge the anesthesiologist during each of the procedures
proposed.
For the ERCP, sedation is routinely recommended.
However, Mr. Smith’s medical conditions will make
sedation challenging and it is possible that a general
anesthesia will ultimately be a safer choice.
For the potential follow-up procedures, either a
laparoscopic cholecystectomy or an exploratory laparotomy, Mr. Smith will need a general anesthesia. Mr. Smith
has a significant increased risk from delirium post operatively, and may need adjustment on his Parkinson’s
medication. Although a laparoscopic cholecystectomy is
generally an ambulatory procedure, serious consideration will need to be given to admit Mr. Smith until it is
clear that he is stable. A major exploratory laparotomy
and biliary dissection carry a very high risk of mortality
in his age group, especially in view of his overall apparent frailty. For the more extensive surgery, Mr. Smith
will need a general anesthesia and invasive monitoring
including an arterial line at a minimum and possibly a
central venous line. Although he has no history of congestive heart failure, if significant blood loss is encountered, he may benefit from cardiac output monitoring
to assist with volume resuscitation. Postoperatively
recovery should include intensive care unit, possible
ventilation, and appropriate pain control. Depending
on his hemodynamic status, he could benefit from a
postoperative thoracic epidural for the treatment of
postoperative pain.
The occurrence of any complications appears to be a
major factor influencing outcomes in the elderly surgical
patient. Several studies have shown a significant increase in
30-day mortality in patients who experienced complications
following noncardiac surgery. In addition, patients experiencing a cardiac or noncardiac complication had a threefold
increase in length of stay. Thus avoiding complications, even
minor ones, and conducting a careful review of the patients’
physical and medical status prior to anesthesia must be a primary focus for all anesthesiologists taking care of older
patients.
The increased morbidity experienced by older patients
largely reflects the burden of disease encountered in this age
group. In a study examining preoperative health status in
elderly patients, over 84% of 544 patients had at least one
comorbid condition [1]. Thirty percent of patients had three or
more preoperative health conditions, 27% had two, and 28%
had one preexisting disease. Hypertension (HTN) was the most
commonly encountered comorbidity. Other common conditions included: diabetes mellitus, dysrhythmias, pulmonary
disease, neurologic disease, arthritis, and ischemic heart
disease including congestive failure. Despite a long list of diseases, functional status and clinical evidence of congestive
heart failure [1, 8] were the two most important predictors of
adverse events postoperatively in this study. Functional status
is particularly important and frequently impacted by the presence of a physical disability. In the oldest patients, over the age
of 80 years, 74% have a disability and 35% of this group
requires assistance with daily activities.
Anesthetic Choices
Aspiration
Regardless of the anesthetic regimen, protection of the
airway is paramount. The geriatric patient is at increased risk
of aspirating because of physiologic changes and common
30725 Choosing the Best Anesthetic Regimen
https://t.me/med1917
disease conditions [10]. A reduction in pharyngeal sensitivity has been demonstrated and common comorbidities such
as a previous cerebrovascular accident, swallowing disorders, and diseases such as Parkinson lead to the increased
possibility of aspiration. The development of aspiration
pneumonia can be devastating in the older patient with
reduced functional reserve. Thus, sedation should be administered cautiously in patients with an unprotected airway
[11,12]. Pulmonary complications were among the most
common in a study comparing young and elderly patients
undergoing noncardiac surgery leading to both an increased
length of stay and subsequent mortality [8].
General Anesthesia
The decision to use a general anesthesia is driven by the
extent of the surgery, and the patient and surgeon preference
[5]. A general endotracheal anesthesia with paralysis allows
maximal exposure for abdominal surgery and is necessary for
abdominal and laparoscopic surgeries. When paralysis is not
required, provided the patient is fasting, not significantly
obese with a low risk of aspiration and the surgery site, and
positioning is appropriate, the laryngeal mask airway (LMA)
has largely replaced the traditional mask anesthetic. For certain very brief surgeries a mask anesthetic is still desirable.
Advantages of intubation compared with the LMA include
the ability to protect the airway from aspiration, and possible
reduction in the risk of development of intraoperative atelectasis through the use of positive pressure volume ventilation
with or without additional positive pressure end-expiratory
pressure. Mucociliary dysfunction occurs after using an LMA
or an endotracheal tube, but it is worse following intubation.
In some instances, a patient will request to be asleep for
a procedure and provided there is no additional risk, patient
preferences should be followed. Dementia increases with
age: in patients of 60–70 years old, the incidence ranges
from 5 to 7%, while in those between 80 and 90 years old,
the incidence ranges from 15 to 20%. Depending on the
ability to cooperate, these patients may require a general
anesthesia or deeper sedation than would normally be indicated by the procedure itself.
Regional Anesthesia
Regional anesthesia includes both neuraxial techniques
such as spinal and epidural anesthesia and peripheral
nerve blocks. Regional anesthesia may be administered as
the primary anesthetic or as an adjuvant for pain relief
during or after the surgery [13]. When utilized to treat
postoperative pain, epidural analgesia and peripheral
nerve blocks improve pain relief, functional outcomes,
and have been shown to reduce hospital stay in selected
patient groups. Advantages of a pure regional anesthesia
include a reduction in the requirement for sedatives, preservation of spontaneous ventilation, the absence of airway
instrumentation, and potential decrease the incidence of
postoperative thrombosis and blood loss following orthopedic surgery [
The choice for a regional anesthesia vs. general anesthesia remains the subject of significant debate [14–17]. Despite
increasing popularity of regional blocks such as intrascalene
and femoral nerve blocks, there is no consistent data supporting a reduction in morbidity or mortality after general
surgery.
14].
Neuraxial Anesthesia
The spine undergoes significant age-related changes, including a gradual deterioration of the intervertebral disks, fibrosis of the intervertebral foramina, and a reduction in fat in the
epidural space. In addition to making the placement of a
spinal or epidural more challenging, these changes also result
in a less compliant epidural space. When dosing the geriatric
patient, enhanced local anesthetic spread can occur in the
spinal column, and the dose of epidural medications should
be reduced and given more slowly [18]. Similarly, local
anesthetic administered through the spinal needle into the
subarachnoid space can result in a variable and higher level
of analgesia and sympathetic block in an older patient due to
a decrease in the CSF and age-related changes in the pain
fibers themselves [19, 20]. In addition to changes in the
spread of local anesthetic agents, metabolism and clearance
of these drugs are also delayed with advanced age. Lidocaine
and other local anesthetic doses should be reduced for both
neuraxial and peripheral nerve blocks. The enhanced
cephalad spread of epidural and spinal local anesthetic agents
also contributes to the increased hypotension observed in
older patients from the consequent sympathectomy. Older
patients are also more sensitive to the central effects of opioids and are at increased risk of apnea following neuraxial
opioid administration.
Epidural analgesia can be employed postoperatively to
improve pain control from large abdominal and thoracic
incisions. Epidural analgesia includes several advantages
over systemic narcotics including improved pain relief, less
sedation, and improved respiratory mechanics. However,
epidural anesthetics usually include low dose local anesthetic agents and this can be associated with a sympathetic
blockade and subsequent potential vasodilatation and
hypotension. The effects of the sympathectomy are often
308 S.R. Barnett
https://t.me/med1917
exaggerated in the elderly patient due to a combination of
existing age-related declines in autonomic function and
increased decline in vascular resistance. The increase in
hypotension in older vs. younger patients can be a significant
factor limiting the use of an epidural for postoperative anal-
gesia or even a spinal for a procedure [3, 13, 20]. In general,
fluid administration alone will not offset the impact of the
sympathectomy and carries the risk of inducing congestive
heart failure once the sympathectomy wears off and the fluid
is returned to the central volume. Epidural- (or spinal)
induced hypotension usually requires treatment with an
alpha agonist such as phenylephrine [3, 13], and this may be
undesirable in patients with tenuous blood supply or new
vascular grafts. In general, if phenylephrine will be deemed
unacceptable in the postoperative course then alternative
postoperative pain management strategies to epidural anesthetics should be considered. Pure opioid analgesia through
the epidural may be useful but significant complications with
postoperative apnea have occurred and limited the use in
elderly frail patients [21].
Absolute contraindications to neuraxial anesthesia
include anticoagulation and antiplatelet medications. Other
contraindications to neuraxial anesthetic include sepsis,
bacteremia, and hypovolemia. Current recommendations
suggest discontinuing warfarin for 3–5 days and allowing
normalization of the INR to 1.5 or less prior to placing an
epidural or spinal. Antiplatelet medications take several
days or weeks to wear off and it is recommended that
ticlopidine be stopped for 14 days and clopidogrel for 7
days at a minimum prior to a neuraxial anesthetic.
Nonsteroidal anti-inflammatory drugs (NSAIDs) and aspirin can be continued. Twice daily low molecular heparin
should be discontinued for 24 h, if only once per day then
12 h is sufficient [22].
In all patients in whom anticoagulation or antiplatelet
medication is an issue, a serious discussion is needed
regarding risks and benefits of discontinuing the medication
and the plans for reinstituting the medications postoperatively. It is important that any plans to change a patient’s
anticoagulation medication involve a discussion with the
patient’s cardiologist or primary care physician.
Monitored Anesthesia Care
This is the most common type of anesthesia administered.
A monitored anesthesia care (MAC) can range from the
administration of minimal anxyiolysis to deep sedation.
In older patients, continuous supplemental oxygen is recommended in all cases as physiological changes with
aging result in a lower arterial oxygen tension on room
air, even before the administration of sedation. In general,
the medication administered by the anesthesia provider is
supplemented by local anesthesia through infiltration or a
field block administered by the surgeon. Patients undergoing an MAC need to be at least partially cooperative and
able to lie still without significant pain; in the older patient
with agitation, dementia, or chronic pain, this can be difficult and a lower threshold for recommending a general
anesthesia may be needed. Similarly, an MAC may be
unreasonable in patients with chronic cough or intractable
tremors.
Minimum Requirements for Anesthesia
Regardless of the anesthetic technique chosen, there are certain minimum requirements that must be met for all patients
undergoing an anesthesia. Patients must have a preoperative
anesthetic evaluation, appropriate laboratory testing, pertinent consultations, and should receive instructions regarding
NPO status and general information on “what to expect following their surgery and anesthesia.” There are several
options for the completion of the preanesthetic evaluation;
the choice will depend on the patient, the surgeon, and the
facility guidelines (Table 25.1).
When a preoperative testing clinic is utilized, the patient
may meet with an anesthesiologist for a full discussion of
anesthetic options. It is recommended that patients are not
promised any particular anesthetic type in advance, the anesthesiologist assigned to the case should be free to make that
decision. In general, older patients with complex medical
CASE STUDY: PART 2
Considering Mr. Smith, he has a high risk of aspiration
due to his Parkinson’s disease. In addition, it is not clear
how cooperative he will be with only sedation. The plan
for his ERCP should include the strong possibility of a
general anesthesia with intubation. A general anesthesia
will definitely be required for either his subsequent laparoscopic cholecystectomy or exploratory laparotomy
and biliary dissection.
Ta b l e 25.1 Preoperative assessment alternatives and the elderly patient
Advantages Disadvantages
Preoperative assessment clinic Reduction lab testing
Expensive
Reduction consultations Cost of administrative clerical staff
Improved OR efficiency Requires allocated hospital space and support
Decrease in OR cancelations and delays Primary MD maybe unaware of surgery
Anesthesiology input Second trip to hospital
Specific NPO instructions
Primary physician visit “clearance” Patient known to MD More laboratory testing
Primary MD involved for postoperative care No anesthesia discussion – especially detrimental
in complex high risk cases
No second hospital visit
Good for simple surgeries No instructions for surgery
Scheduling dependent on MD office availability
Paperwork/clearance at remote site
Telephone interview
Convenient for patient No anesthesia input
Preoperative instructions including NPO Difficult to reach patients at work
Language barriers
Advanced age usually an exclusion factor
Surveys
May be added to above visits/calls
Preoperative health survey Simple No instructions
No extra visits No anesthesia input
No time to optimize medical conditions identified
Mail return unreliable
Internet health quiz Simple No instructions
Remote access to information No anesthesia input
Algorithm for laboratory testing
T
a b l e 25.2 The goals of the preoperative assessment
Obtain a thorough history and physical examination
Provide a risk assessment
Recognize high risk patients
Implement risk reduction strategies
Perform selected laboratory and cardiac testing
Improve control of perioperative diseases
Formulate and discuss the anesthetic plan
Obtain informed consent
Formulate a post operative plan
Reduce anxiety through education
Source: Data from [23]
https://t.me/med1917
30925 Choosing the Best Anesthetic Regimen
histories are best seen prior to surgery to ensure that an
appropriate work-up to optimize the patient’s condition has
been completed [23, 24].
Preoperative Assessment
The aims of the preoperative assessment are to prepare the
patient for anesthesia, obtain consent for the anesthesia, and
ensure that the patient is adequately prepared for their procedure. Chronological age may not accurately reflect a patient’s
physiological age, and a significant goal of the preoperative
assessment is to estimate the patient’s physiologic reserve
function. The physiologic age reflects the combined impact
of aging and comorbid conditions, and is more likely to be
predictive of outcome than age in years alone (Table 25.2).
The assessment can begin with a general assessment of
the geriatric patient: Does the patient look their age? Is there
evidence of cognitive dysfunction or significant disability?
Does the patient’s caregiver answer all the questions? Patients
with preexisting cognitive dysfunction are at higher risk from
postoperative delirium and the anesthetic plan may need to
be altered to accommodate the patient with cognitive or other
disabilities.
Functional status should be assessed during the preoperative
interview, and this is easily achieved using a simple scale as
outlined in Table
25.3. Patients with reduced functional status
(<4 METS) have an increased risk of cardiac morbidity and
poor outcome following noncardiac surgery [25]. The anesthe-
siologist’s physical examination should be focused including
an airway examination and examination of the cardiopulmonary system and other relevant organs.
310 S.R. Barnett
https://t.me/med1917
Ta b l e 25.3 Functional assessment scale
1 MET Can you take care of yourself?
Eat, dress, use the toilet?
Walk indoors around the house
Walk 1–2 blocks on level ground at 2–3
Do light housework?
Can you take care of yourself?
4 METS Climb a flight of stairs? Carry groceries?
Walk on level ground at 4
Run a short distance
Do heavy housework?
Do moderate sports – golf, dance, doubles tennis?
Climb a flight of stairs? Carry groceries?
10 METS Play competitive sports? Singles tennis? Ski?
Source: Data from [
25]
mph?
mph?
Laboratory and Other Testing
Large-scale preoperative laboratory testing in healthy individuals leads to an increase in false positive results and
inappropriate work-ups [26, 27]. Several studies have demonstrated that preoperative screening laboratory testing
rarely provides new information that would not otherwise
have been obtained from a thorough history and physical
examination [26, 28]. Anesthesiologists tend to order fewer
laboratory tests compared with outside referral physicians
and some have found financial benefit derived from anesthesiology-directed laboratory testing vs. other providers.
Except for concurrence on the complete blood count, anesthesiologists generally order fewer tests compared with
surgeons [29–31]. The data refers to laboratory testing that
is being performed to allow safe administration of anesthesia, in all patients, there may be other reasons why additional laboratory testing is requested by a surgeon or
primary care physician in the general course of a patient’s
disease work-up.
A Hemoglobin or hematocrit. It is indicated when the
surgery is associated with significant blood loss potential or
the patient has systemic disease and may be anemic. The
American Society of Anesthesiologists (ASA) practice advisory on preoperative evaluation concluded that age alone
was not an indication for a routine blood count before surgery [32]. However, anemia is more common in the elderly
and may be poorly tolerated in patients with cardiac disease.
In elderly patients undergoing significant surgery, it is not
unreasonable to request a baseline hematocrit.
postoperative anticoagulation is planned generally should
have baseline studies. The other group of patients for whom
coagulation profiles should be considered is those who will
have an epidural or spinal placed [
22].
Electrolytes and blood chemistry. Healthy elderly ambulatory patients or those with mild-to-moderate systemic
disease such as hypertension do not need routine electrolyte levels drawn [29]. Patients scheduled for extensive
procedures such as an exploratory laparotomy or a major
vascular procedure should have baseline blood chemistries, as renal insufficiency occurs in advanced and
hyponatremia is more common in geriatric patients.
Although not routinely ordered, reduced albumin in frail
older patients is a marker of increased risk of mortality
and morbidity [33].
Electrocardiograms. An ECG should be done in patients
with cardiac risk factors and a history of cardiac disease.
Occult cardiac disease is extremely common in older patients
and most institutions recommend age-related screening with
ECGs. A common requirement is a preoperative ECG in
males over the age of 45 years and females over 55 years.
A
prior ECG within 6 months of the surgery in the absence
of ongoing symptoms or changes in cardiac status is frequently acceptable 32, 34, 35].
Consultations
Elderly patients have a very high incidence of cardiac conditions. Ischemic heart disease increases almost exponentially
with age and is frequently under diagnosed. It is not surprising
that cardiac complications are the most significant following
surgery and anesthesia. However, the decision to obtain a
cardiology work-up or consultation prior to surgery will
depend on the severity of the patient’s disease and the onset
of symptoms. Scheduled surgery per se is not an indication
for a cardiac work-up [
Chest radiographs. These are not recommended preoperatively unless indicated by the history or dictated by the
underlying diagnosis. Widespread routine chest X-rays led
to significant morbidity in larger studies secondary to unnecessary follow-up on false positive examinations and unexpected findings were rare [27, 32, 37].
24, 36].
Coagulation studies. These studies are indicated in symptomatic patients with significant liver disease or known coagulopathic conditions. Baseline studies may also be valuable
in patients who are undergoing major surgery with a high
risk of blood loss that are likely to need blood products during the case. Patients on anticoagulants or those for whom
Institutionalized Patients
The preoperative assessment of institutionalized elderly
patients can be especially challenging. It may be difficult or
impractical to require these patients to come to a hospital or
31125 Choosing the Best Anesthetic Regimen
Substance Minimum fasting period (h)
Clear liquids
a
2
Breast milk 4
Infant formula 6
Non human milk 6
Light meal 6
Fried or fatty foods, meat 8
a
Clear liquids include: water, fruit juices without pulp, clear tea,
carbonated beverages, and black coffee
CASE STUDY: PART 3
The preoperative assessment of Mr. Smith will provide critical information for the anesthesiologist. A visit to a preoperative clinic is advisable, and in addition to a general
assessment for his Parkinson’s disease, a brief cognitive
assessment will be valuable to establish a baseline prior to
any surgery. Mr. Smith has a very high risk of developing
postoperative delirium and he and his family should be
warned. In view of his potential for a more significant surgery following his ERCP, Mr. Smith should have baseline
laboratory testing done including a blood count, electrolytes,
and an ECG. From the current history, which does not indicate any new chest pain or shortness of breath, further cardiac testing is not warranted and a chest X-ray is not needed
unless his chest exam reveals abnormalities. Mr. Smith’s
overall poor functional status is a significant concern if he is
required to ultimately undergo a major surgery. A baseline
albumin may provide an indication of his nutritional status
and if reduced, it may be associated with increased risk of
mortality (see physical classification Table 25.4).
Ta b l e 25.4 ASA physical status classes
Class 1. A healthy patient (no physiologic, physical
or psychological abnormalities)
Class 2. A patient with a mild systemic disease without limitation
of daily activities
Class 3. A patient with severe systemic disease that limits activity
but is not incapacitating
Class 4. A patient with incapacitating systemic disease that is a
constant threat to life
Class 5. A moribund patient not expected to survive 24 h with or
without the operation
Class 6. A brain dead patient whose organs are being removed
for donor purposes
Add “E” to denote emergency surgery
https://t.me/med1917
faculty for a special preoperative visit. Frequently, a remote
preoperative screen can be conducted. The facility physician
can be asked to provide a brief history and physical and the
results of any laboratory testing done recently. The preoperative examination can be completed the day of the surgery.
Arrangements for consent from a legal guardian or family
member should be made in advance to prevent delays on the
day of surgery.
After the completion of the preoperative assessment the
anesthesiologist assigns a physical status classification (ASA
1–6). The physical status classification reflects the patient’s
condition and underlying disease complexity, it is independent of the patient’s age. A higher ASA classification carries
independent diagnoses that lead to increased risk from
surgery. In general, risk for anesthesia increases in patients
with more advanced ASA classification. An E is added to the
physical classification to designate a patient for whom a surgery is emergent. The ASA physical classification system is
a useful way to communicate about patients and is used by
many health care providers outside of anesthesia.
NPO Status (Table 25.5)
The ASA has published guidelines for liquid and solid foods
prior to the administration of an anesthetic. For the older
patient, it is important that these instructions are written
and provided to both the caretaker and the patient when
relevant.
Ta b l e 25.5 ASA guidelines for NPO status preoperatively
Medications
Elderly patients are on average taking three medications
and patients must receive clear instructions on which
medications should be held or continued on the day of surgery. In many instances, it is recommended that patients
bring all their medications on the day of preoperative visit
and/or provide a complete list of all medications in advance
of the procedure.
As a general rule, most medications should be continued
until the morning of surgery, especially cardiac and antihypertensive medications. Angiotension converting enzyme
inhibitors (ACEIs) and angiotension receptor blockers
(ARBs) have been associated with profound and prolonged
hypotension following the induction of anesthesia and
provided they are not being administered for congestive heart
failure and these should be held prior to surgery. Similarly,
diuretics can be continued in the presence of significant fluid
312 S.R. Barnett
https://t.me/med1917
CASE STUDY: PART 4
Mr. Smith is an ASA 3 patient, his Parkinson’s disease is
significantly altering his daily life and appears progressive. His medication situation is particularly challenging to prevent acute worsening of his Parkinson’s
symptoms and he should be instructed to continue his
Levo dopa until 3 h prior to surgery. He can take his
other usual medications on the morning of surgery. He
should be instructed to bring his medications with him
to the holding area if his surgery is delayed; he should
overload; however, for the most part thiazide diuretics can be
held for patient convenience. As discussed above, anticoagulation and antiplatelet medications will restrict the anesthesia
choices and the decision to hold anticoagulant and antiplatelet medications should be made by the surgeon. Whenever a
change in these medications is planned, the patient’s primary
care physician should be informed and included in the decision. One-third of older patients have chronic pain and in
these instances it is important to encourage patients to
continue their analgesics until the day of surgery. The
patient’s tolerance to pain medication may require intraoperative adjustment of the anesthetic itself [38].
Special Considerations
Cardiac Adverse Events
In general, the risk of a cardiac event following a noncardiac
surgery is 1–2%, and advanced age (over 65 years) is associated with an almost 2½-fold increase in risk of a significant
event. Other risk factors described recently are consistent
with those mentioned above: the presence of congestive
heart failure (fourfold increase), emergency surgery (twofold), the need for a blood transfusion (almost threefold), and
longer surgery (twofold increase). Past history of cardiac
intervention, cerebrovascular, and hypertension disease was
also significant (almost twofold increase) risk factors for an
adverse event. The intraoperative hemodynamic course is
probably relevant and this study suggested that episodes of
hypotension and tachycardia increased chance of a postoperative event in high risk patients [3, 4, 6].
continue his scheduled anti-Parkinson’s medication.
Given his complex medications, all instructions should
be clearly written for him (Table 25.6).
Ta b l e 25.6 Preoperative instructions
Instructions should be clearly written in simple language
Instructions should be specific avoiding vague or ambiguous
terms such as “maybe”
Directions to exact location in the hospital
Recommendations on clothing and belongings
NPO recommendations – written down
Number to call with change in health
Pulmonary Disease
Five to fifteen percent of elderly patients undergoing surgery
develop a postoperative pulmonary complication. The presence of chronic obstructive pulmonary disease (COPD) can
increase the postoperative mortality rate by tenfold. Risk factors for postoperative pulmonary complications include
severe COPD, advanced age, and undergoing high risk procedures, such as upper abdominal or intrathoracic surgery [8,
39]. The increased risk during surgery in the presence of
COPD relates to a combination of factors related to the
patient, the surgery, and the anesthesia. Patients may exhibit
increased sensitivity to medications through alterations in
central respiratory control and changes in sensitivity to
hypoxemia and hypercapnia; in addition, changes in respiratory mechanics that occur during mechanical ventilation can
persist postoperatively. These detrimental effects may be
exaggerated by residual muscle paralysis and the development of atelectasis and consequent hypoxemia. The trauma
induced by surgical incision can further limit optimal respiration and pulmonary mechanics. In these older patients, full
reversal of muscle relaxant and adequate analgesia is particularly important to overcome the increased work of breathing
associated with advanced age from stiffening of the chest
wall and reduced elasticity of the lung tissues.
Elderly patient’s exhibit reduced threshold for apnea
following narcotic administration and a blunting of the
responsiveness to rising carbon dioxide levels. These changes
leave the geriatric patient susceptible to periods of apnea,
desaturation, and respiratory arrest. Opioid sparing techniques using peripheral nerve blockade or alternate analgesic
such as NSAIDs can be useful if they are compatible with the
surgery [40].
31325 Choosing the Best Anesthetic Regimen
https://t.me/med1917
Regional anesthesia may obviate the need to manipulate
the airway and this may offer advantages in patients with
severely reactive airways disease. However, caution is needed
as COPD patients with significant disease may not tolerate
the associated reduction in respiratory muscle function with
a spinal or epidural anesthetic, especially if they are dependent on active expiration or have excessive secretions requiring frequent coughing [41]. These compromised patients
may experience a significant respiratory depression with a
neuraxial block. Intrascalene nerve blocks may be associated
with diaphragmatic paralysis secondary to phrenic nerve
paresis and should not be used in patients with significant
lung disease.
Renal and Metabolic
Normal aging is associated with a steady decline in baseline
renal function and the choice of anesthesia administered to a
geriatric patient should take into account the potential
reduction in baseline renal function. Postoperative renal
failure is rare but associated with a high mortality rate,
accounting for one-fifth of postoperative deaths in elderly
patients [42]. Associated risk factors for acute postoperative
renal failure include advanced age over 65 years, type 1 diabetes mellitus, preexisting renal insufficiency, major vascular surgery, and recent exposure to nephrotoxins including
NSAIDS, radio contrast dye, and amino glycoside antibiotics. The postoperative renal failure is usually secondary to an
ATN developing as a result of hypotension, hypovolemia,
and/or dehydration.
Nervous System Assessment
In addition to predictable anatomical changes in the central
nervous system, there is an increase in disorders of cognitive
function with an increase in dementia, memory loss, and
degenerative diseases such as Parkinson’s disease. Anatomical
changes include gradual atrophy of the brain, reduction in
gray cells, and widening of the ventricles. Alterations in neurotransmitter levels and neuronal circuits lead to changes in
memory and pharmacodynamic changes resulting in an
increased sensitivity to certain medications such as midazolam and some of the opioids [43]. Alterations in pain perception result from age-related changes in the peripheral nervous
system, such as a reduction in myelinated fibers. In general,
elderly patient’s exhibit increased pain thresholds, and this
may contribute to the delay in presentation of painful conditions such as peritonitis.
Neurodegenerative disorders increase with age and may
influence the administration of anesthesia. One of the most
common is Parkinson’s disease, which afflicts 3% of elderly
persons over 65 years of age. Parkinson’ disease results from
a loss of dopaminergic cells in the ventrolateral aspect of the
substantia nigra of the basal ganglia. Characteristic symptoms include resting tremor, bradykinesia, cogwheel rigidity,
postural instability, and a shuffling gait. The disease is also
associated with autonomic dysfunction and orthostatic
hypotension is common and frequently exacerbated by medication such as l-DOPA and other treatments. Patients with
Parkinson’s disease have increased oral secretions and are at
increased risk of aspiration and laryngospasm during
anesthesia. Orthostatic hypotension may be profound and
medications that induce vasodilatation such as propofol
should be administered cautiously. Parkinson’s medications
should be continued until the time of surgery. l-DOPA
(sinemet), the mainstay of treatment is only available orally
with a relatively short half life of approximately 3 h.
Unfortunately, Parkinson’s patients have a very high incidence of postoperative confusion and delirium that may be
difficult to treat. When possible, a regional anesthesia can be
advantageous or a combined general regional technique that
can lead to improved for postoperative pain control. When
treating Parkinson’s patients, it is important to avoid agents
that may exacerbate the symptoms such as the phenothiazines and metoclopramide.
Postoperative Cognitive Disorders
Postoperative delirium and postoperative cognitive dysfunction (POCD) are common complications in the elderly population [43–45]. Delirium is an acute confusional state, usually
appearing 1–3 days after surgery; it may persist for weeks to
months in afflicted patients. The etiology is multifactorial
including acute medical conditions such as sepsis, hypoxemia, urinary tract infections, and alcohol withdrawal.
Certain medications including meperidine and medications
with anticholinergic effects such as diphenhydramine and
scopolamine are highly associated with delirium, and should
be avoided in the elderly patient [46]. Patients with preexisting dementia, baseline cognitive difficulties and depression
carry a high risk of developing delirium postoperatively.
Delirium is associated with an increase in morbidity and
mortality and also an increase in the length of stay and dependent living situations. When pharmacological intervention is
required, low dose haloperidol starting at 0.25–0.5 mg intravenously may be administered for treatment for agitation.
Midazolam has been associated with a paradoxical excitation in elderly patients with delirium and, in general, it is not
Соседние файлы в папке Библиотека им академика М.И. Перельмана