Anesthesia2.ppt

Friday, August 26, 2022
1
Anesthesia and pulmonary
diseases

2
Thoracic and upper abdominal operations are a particular risk for
patients with chronic pulmonary disease.

Obstructive airway diseases
3
Asthma and chronic obstructive pulmonary disease (COPD), the
two major categories of obstructive airway disease, affect millions
of Americans and cause significant morbidity and mortality
worldwide.

4
Asthma is a chronic inflammatory disorder of the airways
characterized by variable airflow obstruction, airway inflammation,
and bronchial hyperresponsiveness.

5
In contrast, the airflow obstruction in COPD is defined as
progressive and not fully reversible. The chronic inflammation of
the airways and lung parenchyma in COPD is most often
secondary to cigarette smoke exposure.

6
Together, asthma and COPD constitute a major public health
concern, and a basic understanding of these diseases is important
when caring for patients who receive anesthesia.

ASTHMA
7
Asthma is a disease that is defined by the presence of:
(1) Chronic inflammatory changes in the submucosa of the
airways
(2) Airway hyperresponsiveness
(3) Reversible expiratory airflow obstruction.

8
Airway hyperresponsiveness characterizes this disease,
even in asymptomatic patients, and is demonstrated by
the development of bronchoconstriction in response to
stimuli (allergens, exercise, mechanical airway
stimulation) that have little or no effect on normal
airways. Airway hyper responsiveness elicited during
methacholine bronchoprovocation and airway
bronchodilation in response to inhaled albuterol help
diagnose asthma.

Clinical Symptoms
9
The classic symptoms associated with asthma are cough,
shortness of breath, and wheezing. However, symptoms of asthma
may vary and range from cough with or without sputum production
to chest pain or tightness. Chronic,
nonproductive cough may be the sole initial complaint.

10
Some asthmatics also experience symptoms exclusively
with exertion ("exercise-induced asthma"), and this diagnosis
is a consideration in the pediatric and young adult population.

11
The presence or absence of wheezing on physical examination is
a poor predictor of the severity of airflow obstruction. Thus, the
presence of wheezing suggests airway narrowing, which should be
confirmed and quantified by spirometry.

12
Degrees of obstraction are defined according to the FEV1 %
predicted .
Reversibility of obstruction after the administration of a
bronchodilator suggests a diagnosis of asthma.

13
An increase in FEV1 % predicted of more than 12% and
an increase in FEVl of greater than 0.2 L suggest acute
bronchodilator responsiveness and variability in airflow
obstruction.
In contrast, the airways of patients with COPD do not
demonstrate reversibility of airflow obstruction to the
same degree as do those with asthma, a characteristic
that can help distinguish these two causes of airflow
obstraction.

16
During severe asthma exacerbations, intravenous therapy
with glucocorticoids is the mainstay of therapy. In rare
circumstances, when life-threatening status asthmaticus
persists despite aggressive pharmacologic therapy, it may
be necessary to consider general anesthesia (isoflurane or
sevoflurane) in an attempt to produce bronchodilation.

Management of Anesthesia
17
Pulmonary function studies (especially FEV1) obtained
before and after bronchodilator therapy may be indicated
in a patient with asthma who is scheduled for a thoracic
or abdominal operation. Measurement of arterial blood
gases before proceeding with elective surgery is a consideration
if there are questions about the adequacy of ventilation or arterial
oxygenation.

18
All asthmatics who have persistent symptoms should be treated
with either inhaled or systemic corticosteroids (depending on the
severity of their airflow obstruction), in addition to scheduled dose
of inhaled beta agonists. Therapy should be continued throughout
the perioperative period. Supplementation with cortisol may be
indicated before major surgery for corticosteroid-dependent
asthmatics because of suppression of the hypothalamic-pituitary-
adrenal axis.

REGIONAL ANESTHESIA
19
Regional anesthesia may be preferred when the surgery is
superficial or involves the extremities. Notably, however,
bronchospasm has been reported in asthmatics who have received
spinal anesthesia, although it is generally accepted that regional
anesthesia is associated with lower complication rates related to
bronchospasm in the asthmatic population.

GENERAL ANESTHESIA
20
The goal during induction and maintenance of general anesthesia
in patients with asthma is to depress airway reflexes in order to
avoid bronchoconstriction in response to mechanical stimulation of
the airway. Before tracheal intubation, a sufficient depth of
anesthesia should be
established to minimize bronchoconstriction with subsequent
stimulation of the airway. Rapid intravenous induction of anesthesia
is most often accomplished with the administration of propofol or
thiopental. Propofol
may blunt tracheal intubation-induced bronchospasm in
patients with asthma.

21
ketamine (1 to 2 mg/kg IV) is an alternative selection for rapid
induction of anesthesia because its sympathomimetic effects on
bronchial smooth muscle may decrease airway resistance. The
increased secretions associated with the administration of
ketamine, however, may limit the use of this drug in patients with
asthma.
Sevoflurane and isoflurane are potent volatile anesthetics that
depress airway reflexes and do not sensitize the heart to the
cardiac effects of the sympathetic nervous system stimulation
produced by beta-agonists and aminophylline.

22
Bronchodilation with sevoflurane and isoflurane depends on the
ability of the normal airway epithelium to produce nitric oxide and
prostanoids. Halothane is also an effective bronchodilator but may
be associated with cardiac dysrhythmias in the presence of
sympathetic nervous system stimulation.
Desflurane may be accompanied by increased secretions,
coughing, laryngospasm, and bronchospasm as a result of
in vivo airway irritation.

23
Although case reports suggest that bronchodilation follows the
intravenous administration of lidocaine, the clinical significance of
this response is unclear and the data are equivocal.

24
In asthmatic patients undergoing tracheal intubation, premedication
with inhaled albuterol should be the first choice of therapy to
prevent intubation-induced bronchoconstriction.
Neuromuscular blocking drugs that are not associated with
endogenous histamine release may also be used in patients with
asthma .

25
Although histamine release has been attributed to
succinylcholine,there is no evidence that this drug is associated
with increased airway resistance in patients with asthma.

26
Intraoperatively, Pao2 and Paco2 can be maintained at
normal levels by mechanical ventilation of the lungs at
a slow breathing rate (6 to 10 breaths/min) to allow
adequate time for exhalation, an important maneuver
in patients with increased airway resistance. This slow
breathing rate can usually be facilitated by the use of a
high inspiratory flow rate to allow the longest possible
time for exhalation. Positive end-expiratory pressure
(PEEP) should be used cautiously because of the inherent,
impaired exhalation in the presence of narrowed airways.

27
At the conclusion of elective surgery, the trachea may be extubated
while the depth of anesthesia is still sufficient to suppress airway
reflexes. After the administration of anticholinesterase drugs to
reverse the effects of nondepolarizing neuromuscular blocking
drugs, bronchospasm may occur but is not usual, which may reflect
the protective effects (decreased airway resistance) of
simultaneously administered anticholinergics. When extubation is
delayed for reasons of safety until the patient is awake (possible
presence of gastric contents), intravenous administration of
lidocaine may decrease the likelihood of airway stimulation as a
result of the endotracheal tube in an awake patient.

Intraoperative Bronchospasm
28
Airway instmmentation can cause severe reflex bronchoconstriction
and bronchospasm, especially in asthmatic patients with
hyperactive airways. The bronchospasm that occurs
intraoperatively is usually due to factors other than acute
exacerbation of asthma. The frequency of perioperative
bronchospasm in patients with asthma is low, especially if their
asthma is asymptomatic at the time of surgery.

29
It is important to first consider mechanical causes of obstruction
and inadequate levels of anesthesia before initiating treatment of
intraoperative bronchospasm.
Fiberoptic bronchoscopy may be useful to rule out mechanical
obstraction in the tracheal tube. Asthma related
bronchospasm may respond to deepening of anesthesia with a
volatile anesthetic.

30
If the bronchospasm is due to asthma and persists despite an
increase in the concentration of delivered anesthetic drug, albuterol
should be administered by attaching a metered-dose inhaler to the
anesthetic delivery system. When bronchospasm persists despite
B2- agonist therapy, it may be necessary to add intravenous
corticosteroids.

CHRONIC OBSTRUCTIVE PULMONARY DISEASE:
EMPHYSEMA AND CHRONIC BRONCHITIS
31
COPD consists of two entities, emphysema and chronic
bronchitis. The Global Initiative for Chronic Obstructive
Lung Disease (GOLD) guidelines provide criteria
for diagnosis and classification of severity in patients with
symptoms of chronic cough, sputum production, or exposure
to cigarette smoke .

33
Emphysema is characterized by loss of elastic recoil of the lungs,
which results in collapse of the airways during exhalation and
increased airway resistance.

34
Chronic bronchitis is defined by the presence of cough and sputum
production for 3 months in each of 2 successive years in a patient
with risk factors, most commonly cigarette smoking. It has been
estimated that 25% of surgical patients smoke and a further 25%
are ex-smokers, thus making COPD an important diagnosis to
consider in any patient undergoing anesthesia.

Prediction of Postoperative
Outcome
35
The need for preoperative pulmonary function studies
in patients with COPD is controversial because of the
questionable correlation of these tests with postoperative
outcome. Although the FEV! % predicted has been used
to grade the severity of airflow obstraction, data have
shown that using a multidimensional grading system to
assess the respiratory and systemic extent of COPD is a
better predictor of mortality than using FEV, % alone.

BODE index.
36
This grading system is based on four variables-
1=Body mass index (B)
2=Severity of airflow obstraction (0)
3=Functional dyspnea (D)
4=Exercise capacity as assessed by the 6-minute walk test (E)

38
Patients with higher BODE scores were at higher risk for death.
Hypercapnia and hypoxemia, as detected by arterial blood gas
analysis, may also characterize patients with moderate to severe
airflow obstmction. Chronic hypoxemia may lead to
pulmonary hypertension and cor pulmonale. Preoperative
detection plus treatment of hypoxemia-induced cor
pulmonale with supplemental oxygen is an important
part of preoperative management.

39
The presence of COPD does not dictate the use of specific
management of anesthesia. If general anesthesia is selected, a
volatile anesthetic with humidified inhaled gases and mechanical
ventilation of the lungs is useful. drugs or techniques (regional or
general) for the management of anesthesia.

40
Nitrous oxide may be used, but potential disadvantages include
limitation of the inhaled concentrations of oxygen and passage of
nitrous oxide into emphysematous bullae.
Nitrous oxide could lead to enlargement and rupture of these bullae
and result in the development of tension pneumothorax.

41
Opioids are acceptable but are less ideal for maintenance of
anesthesia because of the frequent need for high inhaled
concentrations of nitrous oxide to ensure amnesia and associated
decreases in inhaled concentrations of oxygen. To avoid this
problem, administration of a volatile anesthetic at a low
concentration may be substituted for nitrous oxide. Postoperative
depression of ventilation may also reflect the residual effects of
opioids administered intraoperatively.

MANAGEMENTOF VENTILATION
42
Patients with COPD are ventilated in a manner similar to
those with asthma. Small tidal volumes may be delivered
to decrease the likelihood of gas trapping and barotrauma.
Slow breathing rates are used to permit maximal time for
exhalation. Continued tracheal intubation and mechanical
ventilation of the lungs in the postoperative period are
often necessary after major surgery in patients with severe
emphysema. Postoperative depression of ventilation may
also reflect the residual effects of opioids administered.

43
Hypercapnia secondary to chronic hypoventilation should not be
corrected intraoperatively because it may then be difficult to wean
the patient from mechanical ventilation as a result of the decreased
respiratory drive in patients who chronically hypoventilate.

Pulmonary HYPERTENSION
44
Pulmonary hypertension is defined as an elevation in
mean pulmonary artery pressure to levels higher than
25 mm Hg at rest or higher than 30 mm Hg with exercise.
Most cases of pulmonary hypertension are secondary to
cardiac or pulmonary disease; in a minority of cases, the
etiology is unknown and the pulmonary hypertension is
considered primary.

Classification
45
The World Health Organization has proposed a classification
of pulmonary hypertension that includes pulmonary
hypertension secondary to left heart disease, pulmonary
disease, vascular disease, and primary pulmonary hypertension.
Indicators of disease severity include dyspnea at rest, hypoxemia,
syncope, metabolic acidosis indicating
low cardiac output, and signs of right heart failure on
physical examination (elevated jugular venous pressure,
hepatomegaly, and peripheral edema).

Diagnostic Evaluation
46
Diagnostic evaluation for pulmonary hypertension includes
the electrocardiogram; echocardiogram; chest roentgenogram;
assessment for secondary causes such as pulmonary
embolism (computed tomographic angiography or
ventilation/perfusion scanning), underlying pulmonary
disease (pulmonary function testing), collagen vascular
disease, or liver failure; and right heart catheterization.

47
Right heart catheterization is the gold standard for diagnosis
because it provides data on the severity of pulmonary
artery hypertension, as well as pulmonary venous pressure
and cardiac output, which have prognostic significance.
In addition, right heart catheterization is a necessary part
of testing for vasodilator response, the first step in the
algorithm to determine appropriate therapy for pulmonary
artery hypertension.

Pathophysiology
48
Chronic elevation of pulmonary artery pressure leads to
elevated right ventricular systolic pressure, hypertrophy
and dilatation of the right ventricle, and resultant right
ventricular failure. Right ventricular preload and pulmonary
blood flow are dependent on venous return in this setting.

49
Intraoperative considerations for a patient with severe pulmonary
hypertension include maintaining adequate preload, minimizing
tachycardia and cardiac dysrhythmias that may decrease cardiac
output, and avoiding arterial hypoxemia and hypercapnia, which
can increase pulmonary vascular resistance (PVR). Cardiac output
from a failing right ventricle is critically dependent on filling
pressure from venous return and pulmonary pressure.

50
Options for treatment of pulmonary hypertension during surgery
include inhaled nitric oxide (10 ppm), inhaled prostacyclin (either
intermittent or continuous), and phosphodiesterase inhibitors such
as milrinone. Pulmonary artery catheters have been used for
intraoperative monitoring.

PARTURIENTS
51
Mortality in pregnant patients undergoing vaginal delivery
is near 50% and may be even higher when cesarean delivery
is performed. Most often, vaginal deliveries are preferred,
although regional anesthesia may be used successfully during
cesarean sections. The danger of decreased venous return
secondary to the sympathetic nervous system blockade
produced by regional anesthesia should be considered.

POSTOPERATIVE PERIOD
52
In the postoperative period, care must be taken to avoid
large-volume fluid shifts, arterial hypoxemia, systemic
hypotension, and hypovolemia in patients with pulmonary
hypertension. Morbidity and mortality in the postoperative
period are significant concerns, with possible causes
including pulmonary vasospasm, increases in pulmonary
artery pressure, fluid shifts, cardiac dysrhythmias, and
heightened sympathetic nervous system tone.

OBSTRUCTIVE SLEEP APNEA
53
Patients with obstructive sleep apnea (OSA) are at high risk for
postoperative complications when undergoing general anesthesia.
OSA is reported to occur in 2% of middle-aged women and 4% of
middle-aged men. It is suspected, however, that up to 80% of
cases of OSA are undiagnosed, thus suggesting that those with this
disorder may be a significant portion of the surgical population.

54
Obesity is the most significant risk factor for the development
of OSA, with a body mass index greater than 30 and a large neck
circumference (>44 cm) being positively correlated with severe
OSA. Obese patients with OSA or suspected OSA are at risk for
complications during tracheal intubation and extubation, as well as
during the postoperative period.,

55
Comorbid medical illnesses such as hypertension cardiovascular
disease, and congestive heart failure are also more prevalent in
patients with OSA than in the general population, a fact that
contributes to their postoperative morbidity. Systemic hypertension
has been reported in up to 50% of patients with OSA and is
independent of obesity, age, and gender.

56
Treatment of OSA by noninvasive ventilation results in better
control of systemic hypertension. In addition to systemic
hypertension, pulmonary hypertension is more prevalent in these
patients than in the general population, One common
mechanism that may explain both the systemic and pulmonary
hypertension in patients with OSA is the chronic decrease
in Pa02 during apneic episodes.

57
Evaluation of the oral cavity in patients with OSA may not reveal
the true nature of their pharyngeal space because increased fat
deposition in the lateral pharyngeal walls has been demonstrated in
these patients and shown to correlate with the severity of OSA.
Neck circumference reflects pharyngeal fat deposition and
correlates more strongly with the incidence and severity of OSA
than general obesity dose.

IMPACT OF SEDATIVE DRUGS
58
Relaxation of the upper airway musculature in response to
benzodiazepines may significantly reduce the pharyngeal
space and result in longer periods of hypopnea, arterial hypoxemia,
and hypercapnia in patients with OSA than in the general
population.

59
Any medications that depress the central nervous system must be
administered carefully because airway patency and skeletal muscle
tone, maintained in the awake state, may be lost at the
onset of sleep. In addition, opioid analgesics may decrease
the central respiratory drive and thus further add to the
possible complications of sedation.

ANTICIPATION OF DIFFICULT AIRWAY
MANAGEMENT
60
Full preparation for difficult airway management, including
the availability of orotracheal tubes of various size, a
Fastrach laryngeal mask, and a fiberoptic bronchoscope,
should be made before initiating direct laryngoscopy for
tracheal intubation.

61
Adequate preoxygenation is necessary in obese patients with OSA
because of their reduced functional residual capacity and risk for
arterial hypoxemia with induction of anesthesia. Tracheal
extubation should be performed only when the patient is breathing
spontaneously with adequate tidal volumes, oxygenation, and
ventilation.

MANAGEMENTIN THE
POSTOPERATIVE PERIOD
62
Respiratory depression and repetitive apnea in the postoperative
period can occur in patients with OSA,
especially in the setting of opioid administration for pain
control. It should also be noted that in patients with OSAwho
hypoventilate (obesity-hypoventilation syndrome),
careful documentation of preoperative arterial blood gases is
necessary to establish the baselinc set point for ventilation, an
important factor whcn considering the patient's respiratory drive
after extubation.

63
Relativc hyperventilation intraoperatively to maintain a
norma] Paco2 in subjects who chronically hypoventilate
may result in prolonged apnea when attempting
extubation.

Smoking Cessation
64
The risk for postoperative pulmonary complications
among smokers as opposed to nonsmokers is greatly
increased.The length of preoperative smoking
cessation necessary to decrease this risk is not clear. It
is generally accepted that the increased incidence of
postoperative pulmonary complications in smokers can
be reduced significantly by persuading the patient to
stop smoking before surgery, although there is no
consensus on the minimal or optimal duration of
preoperative abstinence.

DISCONTINUATION OF SMOKING
65
Smoking increases airway irritability and secretions, decreases
mucociliary transport, and increases the incidence of postoperative
pulmonary complications. Cessation of smoking for 12 to 24 hours
before surgery decreases the level of carboxyhemoglobin, shifts
the oxyhemoglobin
dissociation curve to the right, and increases the oxygen available
to tissues.

66
In contrast to these short-term effects, improvement in mucociliary
transport and small airway function and decreases in sputum
production require prolonged abstinence (8 to 12 weeks) from
smoking. The incidence of postoperative pulmonary complications
decreases with abstinence from cigarette smoking for

67
Nevertheless, it is useful to encourage smoking abstinence in the
perioperative
period, especially because smoking shortly before surgery may be
associated with an increased incidence of ST-segment depression
on the electrocardiogram.

Tuberculosis
69

Tuberculosis
70
Mycobacterium tuberculosis is an obligate aerobe responsible
for TB. This organism survives most successfully in tissues
with high oxygen concentrations, which is consistent with the
increased presentation of TB in the apices of the lungs.

71
Almost all M. tuberculosis infections result from aerosol
(droplet) inhalation. It has been estimated that up to 600,000
droplet nuclei are expelled with each cough and remain viable
for several days. Although a single infectious unit is capable
of causing infection in susceptible individuals, prolonged
exposure in closed environments is optimal for transmission
of infection.

72
It is estimated that 90% of patients infected with M.
tuberculosis never become symptomatic and are identified
only by conversion of the tuberculin skin test. Often patients
who acquire the infection early in life do not become
symptomatic until much later. Patients who are HIV
seropositive or immunocompromised are at much higher risk
of becoming symptomatic

73
Sputum smears and cultures are also used to diagnose TB.
Smears are examined for the presence of acid-fast bacilli. This
test is based on the ability of mycobacteria to take up and
retain neutral red stains after an acid wash. It is estimated that
50% to 80% of individuals with active TB have positive sputum
smears. Although the absence of acid-fast bacilli does not rule
out TB, a positive sputum culture containing M. tuberculosis
provides a definitive diagnosis.

74
Health care workers are at increased risk of occupational
acquisition of TB. For example, TB is twice as prevalent in
physicians as in the general population. Persons involved with
autopsies are uniquely at risk.

Diagnosis
75
The diagnosis of TB is based on the presence of clinical
symptoms, the epidemiologic likelihood of infection, and the
results of diagnostic tests. Symptoms of pulmonary TB often
include persistent nonproductive cough, anorexia, weight
loss, chest pain, hemoptysis, and night sweats. The most
common test for TB is the tuberculin skin (Mantoux) test. The
skin reaction is read in 48 to 72 hours, and a positive reading
is generally defined as an induration of more than 10 mm.

76
For patients with AIDS, a reaction of 5 mm or more is
considered positive. The skin test is limited, and alternative
screening and diagnostic tests are undergoing evaluation. The
skin test is nonspecific and may be positive if people have
received a bacille Calmette-Guérin vaccine or if they have
been exposed to TB, or perhaps even other mycobacteria,
even if there are no viable mycobacteria present at the time of
the skin test.

77
Chest radiographs are important for the diagnosis of TB.
Apical or subapical infiltrates are highly suggestive of
infection. Bilateral upper lobe infiltration with the presence of
cavitation is also common. Patients with AIDS may
demonstrate a less classic picture on chest radiography,
which may be further confounded by the presence of PCP.
Tuberculous vertebral osteomyelitis (Pott's disease) is a
common manifestation of extrapulmonary TB.

78
Anesthesiologists are at increased risk of nosocomial TB by
virtue of events surrounding the induction and maintenance of
anesthesia that may induce coughing (tracheal intubation,
tracheal suctioning, mechanical ventilation).Bronchoscopy is
a high-risk procedure associated with conversion of the
tuberculin skin test in anesthesiologists. As a first step in
preventing occupational acquisition of TB, anesthesia
personnel should participate in annual tuberculin screening
such that those who develop a positive skin test may be
offered chemotherapy. The decision to take chemotherapy is
not trivial as treatment for TB carries the serious toxicity. A
baseline chest radiograph is indicated when a positive
tuberculin skin test first manifests

Treatment
81
Anti-TB chemotherapy has decreased mortality from TB by
more than 90%.With adequate treatment, more than 90% of
patients who have susceptible strains of TB have
bacteriologically negative sputum smears within 3 months. In
the United States, vaccination with bacille Calmette-Guérin is
not recommended, as it may not confer immunity and
confounds the diagnosis of TB.

82
Some argue that, for protection of the community, people who
have positive skin tests should receive chemotherapy with
isoniazid. However, the flipside is that isoniazid is a toxic drug
and treatment is only strictly indicated if there are
radiographic features of pulmonary TB or if there are
suggestive symptoms. The toxicity of isoniazid manifests in
the peripheral nervous system, liver, and possibly the kidneys.
Neurotoxicity may be prevented by daily administration of
pyridoxine. Hepatotoxicity is most likely to be related to
metabolism of isoniazid by hepatic acetylation. Depending on
the genetically determined traits, patients may be
characterized as slow or rapid acetylators. Hepatitis appears
to be more common in rapid acetylators, consistent with the
greater production of hydrazine, a potentially hepatotoxic
metabolite of isoniazid. Persistent elevations of serum
transaminase concentrations mandate that isoniazid be
discontinued, but mild, transient increases do not.

83
Other drugs used to treat TB include pyrazinamide, rifampicin,
and ethambutol. Adverse effects of rifampicin include
thrombocytopenia, leukopenia, anemia, and renal failure.
Hepatitis associated with increases in serum
aminotransaminase concentrations occur in approximately
10% of patients being treated with rifampicin. In order to be
curative, treatment for pulmonary TB is recommended for 6
months. Extrapulmonary TB usually requires a longer course.
Noncompliance with therapy contributes to the emergence of
resistant TB strains.

84
The preoperative assessment of patients considered to be at
risk of TB includes a detailed history, including the presence
of a persistent cough and the tuberculin status.Elective
surgical procedures should be postponed until patients are no
longer considered infectious. Patients are considered
noninfectious if they have received antituberculous
chemotherapy, are improving clinically, and have had three
consecutive negative sputum smears.

85
If surgery cannot be delayed, it is important to limit the
number of involved personnel, and high risk procedures
(bronchoscopy, tracheal intubation, and suctioning) should be
performed in a negative-pressure environment whenever
possible. Patients should be transported to the operating
room wearing a tight-fitting N-95 face mask to prevent casual
exposure of others to airborne bacilli. Staff should also wear
N-95 masks.

86
If patients have TB of the cervical spine, special precautions
should be taken not to injure the spine during airway
manipulation. A high efficiency particulate air filter should be
placed in the anesthesia delivery circuit between the Y
connector and the mask, laryngeal mask airway, or tracheal
tube. Bacterial filters should be placed on the exhalation limb
of the anesthesia delivery circuit to decrease the discharge of
tubercle bacilli into the ambient air. Sterilization of anesthesia
equipment (laryngoscope blades) is with standard methods
using a disinfectant that destroys tubercle bacilli.

87
Use of a dedicated anesthesia machine and ventilator is
recommended. Positive-pressure ventilation has been
associated with massive hemoptysis in a patient with old
pulmonary TB leading to the recommendation that
maintenance of spontaneous breathing may be indicated in
selected patients. Postoperative care should, if possible, take
place in an isolation room, preferably with negative pressure.

lists important considerations in regard to
tuberculosis.
88
1. With the acquired immunodeficiency syndrome epidemic,
tuberculosis is reemerging worldwide.
2. Multidrug resistant and extensively drug-resistant strains
are resistant to therapy and have increased virulence.
3. Symptoms include persistent cough, anorexia, weight
loss, chest pain, hemoptysis, and night sweats.
4. Anesthesiologists are at increased risk of nosocomial
tuberculosis.
5. Treatment for pulmonary tuberculosis is recommended for
6 months.

89
6. Noncompliance with therapy contributes to the emergence
of resistant tuberculosis strains.
7. Staff and patients should wear N-95 masks.
8. A dedicated anesthesia machine and ventilator should
ideally be used.
9. Postoperative care should take place in an isolation room
with negative pressure.

UPPER RESPIRATORY TRACT
INFECTIONS
90
Patients may arrive at the hospital for elective tonsillectomy and
adenoidectomy with an acute upper respiratory tract infection.
Surgery for these patients is usually postponed until resolution of
the upper respiratory tract infection, which is typically 7 to 14 days.
Laryngospasm with airway manipulation may be more likely to
occur in the presence of an upper respiratory tract infection.

91
URI has diffuse effects on the respiratory epithelium, mucociliary
function, and airway reactivity. These effects combine to provide
the potential for an increased risk for anesthesia in specific clinical
settings. If the planned surgical
procedure is short and airway support is restricted to the use of a
facemask, the risk for an adverse respiratory event is minimal.

92
If an endotracheal tube is required, the risk for an adverse
respiratory event is increased (up to 10- fold) over that in an infant
without a URI whose trachea
is not intubated. An LMA seems to be associated with risks midway
between those associated with a facemask and those with an
endotracheal tube. Younger age plus a ORI seems to be
associated with an increased risk from anesthesia. URIs develop
recurrently in 1- to 6-year-olds, and if reactive airways accompany
the infection, the effect on the airway persists for 2 to 6 weeks.

93
Ultimately, the preoperative evaluation must weigh the
inconvenience of rescheduling
against ignoring possible risks. If the decision is to
proceed with elective surgery, the infant should be
considered to have reactive airways.

94
The decision to cancel surgery on a child with an uncomplicated
ORI always requires assessment from the viewpoint of a specific
patient and family, a specific procedure, and a specific surgeon. A
strict protocol for when to
cancel surgery is impractical. The patient's age, medical and
anesthetic history, current physical examination, planned surgery
(placement of tympanostomy tubes versus surgery for craniofacial
repair), and anticipated postoperative care (need for mechanical
ventilatory support) must be analyzed.

95
Ultimately, the preoperative evaluation must weigh the
inconvenience of rescheduling against ignoring possible risks. If the
decision is to proceed with elective surgery, the infant should be
considered to have reactive airways.

Epiglottitis
96
Acute epiglottitis is an infectious disease caused by Haernopbilus
infiuenzae type B. It can progress rapidly from a sore throat, to
airway obstruction, to respiratory
failure and death if proper diagnosis and treatment are delayed.
Patients are usually between 2 and 7 years of age, although
epiglottitis has been reported in younger
children and adults.

97
Characteristic signs and symptoms of acute epiglottitis include
(1) a sudden onset of fever, dysphagia, drooling, thick muffled
voice, and preference for the sitting position with the head
extended and leaning forward (2) retractions, labored breathing,
and cyanosis when respiratory obstruction is present.

Treatment
98
Direct visualization of the epiglottis should not be attempted in an
awake patient because it could lead to airway compromise and
death. Interactions with the patient should be kept to a minimum.
Stimulation of the patient or the onset
of struggling during attempted treatment procedures may result in
exacerbation of the airway obstruction. Induction of anesthesia is
often accomplished with the
inhalation of sevoflurane (alternatively, halothane) while
maintaining spontaneous ventilation.

99
It is important to secure the airway without stimulating the reactive
airway.
An emergency airway cart and tracheostomy tray should be
available and open, with appropriate personnel present should an
emergency surgical airway be needed.

100
Postoperative management takes place in the intensive care unit
and consists of continued observation and radiographic
confirmation of tracheal tube placement. Tracheal extubation is
usually attempted 48 to 72 hours
later when a significant leak around the endotracheal tube is
present and visual inspection of the larynx by flexible fiberoptic
bronchoscopy confirms a reduction in swelling of the epiglottis and
surrounding tissue.

Anesthesia2.ppt

Recommended

Recommended

More Related Content

Similar to Anesthesia2.ppt

Similar to Anesthesia2.ppt (20)

More from deepti sharma

More from deepti sharma (11)

Recently uploaded

Recently uploaded (20)

Anesthesia2.ppt

Editor's Notes