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operative analgesia.16 ade. Although recent radiologic evidence suggests that adult
Preoperative consultation should include a history and physi- patients with Laron syndrome have narrowing of the spinal
cal examination with emphasis on the airway and anatomical canal at the cervical level, little is known about stenosis of
the lumbar region.17 It is presumed that the spinal cord is propor-
landmarks relevant to regional anesthesia. If respiratory compro-
mise is present, arterial blood gas analysis, pulmonary function tionately reduced in size relative to the volume of the spinal canal,
tests, and chest radiographs may be indicated. Measurement of but this is not known for certain. If the spinal cord were to be large
oxyhemoglobin saturation using pulse oximetry with the patient in relation to the size of the spinal canal, or to terminate at a lower
in the upright and Trendelenburg positions is a useful screening than expected level, an increased risk of neurologic damage with
test to detect potential deterioration with decreases in FRC. No regional (particularly spinal) anesthesia might be present.
additional laboratory or radiological studies are necessary in the However, in an emergency situation, a continuous spinal might
absence of other complicating conditions. Routine noninvasive provide more rapid onset of anesthesia than an epidural.
monitoring is adequate during labor and delivery in patients As in individuals of normal size, a test dose can be used to
without other complicating factors. If respiratory problems are identify inadvertent epidural catheter placement in the subarach-
present, intra-arterial catheter placement with monitoring of noid space or in an epidural vein. Test doses for labor analgesia
oxygenation, ventilation and acid-base status may be prudent. are controversial but we believe that a test dose is useful when
In those instances where vaginal delivery is anticipated, intra- surgical analgesia is desired. The optimal test dose in dwarfs is
venous (i.v.) or intramuscular opioids may be useful. However, unknown, but it is prudent to reduce the dose of local anesthetic
epidural analgesia provides superior pain relief without respira- and consider the dose of epinephrine on the basis of patient
tory depression and is the technique of choice. The appropriate weight. In the case mentioned above, a 2 ml test dose of 2%
lidocaine with 1:200 000 epinephrine was used safely.16 It was
dose of a dilute local anesthetic, in combination with an opioid,
can be titrated slowly in order to achieve adequate analgesia. felt that, in the event of an inadvertent subarachnoid injection,
Patient-controlled epidural analgesia can be used for maintenance this dose would have provided evidence of spinal blockade with-
with conservative bolus doses, approximately half to two-thirds out producing an excessively high level. The dose of 10 mg of
of the initial bolus volume, used initially. If C/S is necessary, as epinephrine may have been inadequate for identification of intra-
is frequently the case, additional local anesthetic can be injected venous placement of an epidural catheter, compared with the
more commonly accepted 15 mg dose.18 However, on a micro-
to provide surgical anesthesia. Careful titration is essential to
avoid high epidural blockade with the potential for respiratory gram per kilogram basis, the epinephrine dose was slightly
embarrassment. greater than that normally used. Careful incremental injection
For patients undergoing planned C/S, a continuous technique of local anesthetic is critical to avoid risk of i.v. injection or high
is preferable to a single-shot technique. We prefer continuous segmental block.
epidural over continuous spinal anesthesia because of the lower Although a single-dose spinal anesthetic can be performed, the
incidence of headache and perhaps lower potential for neurologic appropriate dosage of local anesthetic may be difficult to predict
deficit. However, a continuous spinal anesthetic can be used with because of the presence of a shortened spinal cord. Local



117
2 Musculoskeletal disorders


anesthetic doses comparable to those used in the pediatric popu- proportionate short stature. Etiologies of disproportionate short
lation may be appropriate. However, no studies have been per- stature include the osteochondrodysplasias (abnormalities of
formed in this population to confirm this. Potential problems cartilage and/or bone growth and development) and primary
metabolic diseases that involve the skeleton.2,22 Patients with
with subarachnoid blockade include underdosage, resulting in
inadequate anesthesia for C/S, as well as overdosage, resulting primary metabolic diseases frequently do not survive into adult-
in high spinal anesthesia with the risk of loss of airway control, hood or are infertile.
respiratory arrest, hemodynamic instability, and cardiac arrest.
While some authors have advocated general anesthesia (GA)
Achondroplastic dwarfism
for all patients with nonproportionate short stature,14 no such
recommendation exists for dwarfs with proportionate short Achondroplastic dwarfism is the most common type of dwarfism,
with a prevalence rate of 0.5 to 1.5 per 10 000 births.3 A summary
stature. However, since descriptions of such dwarfs have
included micrognathia as a clinical feature, difficult intuba- of the anatomic and physical characteristics of achondroplasia is
tion is a potential problem. Furthermore, a prospective study listed in Table 6.4. Short stature in this condition is a result of
performed on patients with Laron syndrome found a high abnormal endochondral bone formation. These patients have
incidence of cervical spinal stenosis, atlanto-odontoid osteoar- normal truncal lengths, but shortened limbs, which are primarily
thritic changes, and a decreased mediolateral diameter of the responsible for their short stature. Achondroplastic dwarfs are
usually no taller than 130 cm.2 The disease is caused by a muta-
oropharynx. These findings led the authors to recommend
routine cervical spine imaging (preferably magnetic resonance tion in the fibroblast growth factor receptor gene, which results in
decreased endochondral ossification.23 The mode of inheritance
imaging [MRI]) in these patients. We believe MRI should be
performed if time permits.17 Regardless, caution should be
used and a thorough airway evaluation performed prior to
induction of GA in order to avoid difficulties with airway
Table 6.4 Achondroplasia: anatomic and physical findings
management. If imaging of the cervical spine is not available,
awake fiberoptic intubation should be considered, especially General: Normal trunk length
in patients with symptoms consistent with cervical spinal Short limbs
column narrowing. Craniofacial: Megalocephaly “ large head size
Prediction of the appropriate size of endotracheal tube (ETT) Megalencephaly “ large brain size
for proportionate dwarfs is difficult. Whereas age is usually the Brachycephaly “ short head
best guide to ETT size in children, weight was found to be a better Foramen magnum stenosis
predictor in pediatric patients with proportionate small stature.19 Decreased atlanto-occipital
Precautions against aspiration are particularly important in preg- distance
nant dwarfs because the uterus causes additional impingement Frontal bossing
on intra-abdominal structures.20,21 For the same reason, supine Depressed nasal bridge
hypotension may be more problematic than in the normal-size Maxillary/facial hypoplasia
parturient. Macroglossia
Pain management after C/S can utilize epidural opioids, pre- Narrowed upper airways
ferably in a reduced dosage, but no schedule for appropriate Central nervous system: Hydrocephalus
dosage of epidural opioids exists in dwarfs. In view of the poten- Hypotonia
tial risk for respiratory depression, we recommend a high level of Spine/skeletal: Generalized spinal stenosis
postoperative monitoring including frequent vital signs and use Odontoid dysplasia
of continuous pulse oximetry for 16“24 hours. Atlanto-axial instability
Abnormally shaped vertebrae
Neonatal considerations Hyperplastic intervertebral discs
Lumbar hyperlordosis
Infants born to mothers with isolated GH deficiency are usually of Thoracolumbar kyphosis
normal birth weight and length.8 The diagnosis of dwarfism in the Square ilia
offspring is made either in infancy or in childhood, as growth does Narrow sciatic notch
not progress at a normal rate. Laron dwarfs have birth lengths that Horizontal sacrum
are abnormally shorter than average, with a normal birth weight.7 Respiratory/cardiac: Chest deformities
Considerations for immediate neonatal resuscitation are similar Thoracic dystrophy/kyphosis
to those for other infants born to mothers with a small pelvis. Rib hypoplasia
Upper airway obstruction
Disproportionate short stature Obstructive sleep apnea
Cor pulmonale
Patients with disproportionate short stature are potentially more Possible pulmonary hypertension
complicated from an anesthetic perspective than those with



118
Chapter 6


in achondroplasia is autosomal dominant, although 80% are a the larynx, so intubation attempts were abandoned and a laryngeal
result of spontaneous mutation.23,24 mask airway (LMA) was placed. The same patient required endo-
Achondroplastic dwarfs usually are diagnosed at birth, and have tracheal intubation with the aid of a stylet on another occasion.
numerous craniofacial abnormalities such as megalocephaly (large One case report of difficult intubation in achondroplastic patients
attributes the problem to limited neck extension27 while another
head size), megalencephaly (overgrowth of the brain), frontal bos-
sing, and a depressed nasal bridge (see Figure 6.2).2,11 Maxillary describes difficulties due to subglottic stenosis.28
hypoplasia, a large mandible, and a large tongue may be present in Numerous spinal anomalies can occur in achondroplastic dwarfs.
these individuals,25 and indicate a potential for difficult airway Thoracolumbar stenosis and generalized spinal stenosis are frequent
findings.29,30,31,32 Additional abnormalities include lumbar hyperlor-
management. In a series of 36 anesthetics performed in 27
patients, Mayhew et al.25 reported no difficulty in airway manage- dosis and/or thoracolumbar kyphosis, thoracic dystrophy, square
ment either with mask ventilation or direct laryngoscopy. In a ilia, a narrow sciatic notch, and a horizontal sacrum. Because of the
report by Monedero et al.26 airway complications did not occur lumbar lordosis, the fifth lumbar vertebra seems to have a lower
position relative to the ilia than is seen in the nondwarf population.33
during 53 general anesthetics for 15 mostly pediatric achondro-
plastic patients undergoing orthopedic surgery. However, the Narrowing of the spinal canal (spinal stenosis) can occur at any
spinal level,33 although the thoracolumbar and lumbar regions
report described one patient in whom it was impossible to visualize


Figure 6.2 Achondroplasia associated with short limbs,
characteristic facies, and contracted pelvis. Reprinted with
permission from C. V. Mosby Co. from Tyson, J. E., Barnes, A. C.,
McKusick V. A. et al. Obstetric and gynecologic considerations of
dwarfism. Am. J. Obstet. Gynecol. 1970; 108: 688“703.




119
2 Musculoskeletal disorders


are the most commonly narrowed segments in achondroplastic out of 26 achondroplastic pregnant women had respiratory diffi-
dwarfs. Spinal cord compression can result from narrowing due culties during the last two months of gestation. The etiologies
to abnormally shaped vertebrae or hyperplastic intervertebral include chest deformities, upper airway obstruction, sleep apnea,
discs.29 The narrowing of the spinal canal from underdeveloped neurologic problems, and other unrelated pulmonary condi-
tions.3 Thoracic cage deformities, including rib hypoplasia and
vertebral arches and shallow vertebral bodies results in a nar-
rowed epidural and subarachnoid space,34 which has anesthetic other rib deformities, can cause restrictive lung disease.
implications when regional anesthesia is attempted. Additionally, these mechanical problems may be associated
with recurrent respiratory tract infections.2,49,50,51 As in non-
Additionally, the abnormal intervertebral discs frequently
bulge laterally and posteriorly and can cause neurologic defi- dwarfs, severe kyphoscoliosis can cause baseline hypoxemia
cits.2,35 Anatomic findings in one cadaveric achondroplastic and low lung volumes, which tend to worsen during sleep (or
anesthesia).52 In adult achondroplastic dwarfs, Stokes53 demon-
spine from a patient who had suffered from nonvascular claudi-
cation symptoms revealed thickened pedicles, inferior facet strated that it is the shape of the thorax that differs most com-
encroachment, and nerve root stenosis.36 These physical findings pared with the anatomy of nondwarf individuals. The expansion
were consistent with the symptomatology seen in this patient prior of the uterus to become an intra-abdominal organ very early in
to death from an unrelated cause. Because symptoms of neurolo- gestation limits respiratory mechanics more in dwarfs than in
gic compromise can progress to paralysis,29,32,33,36,37,38,39,40 it is women of normal stature. The additional decrease in FRC that
critical for the anesthesiologist to be aware of and document any occurs in pregnancy can worsen respiratory status in individuals
with significant kyphoscoliosis.20,54
neurologic symptoms prior to anesthetic intervention. In a series
of 46 pregnant dwarfs, 4 out of 26 achondroplastic patients had The mechanism of upper airway obstruction in achondroplasia
symptoms of nerve root compression consisting of numbness and is unclear. It may be due to mechanical factors such as brachy-
tingling in the lower limbs.14 No mention is made of the route of cephaly (short head),11 a flattened nasal bridge, facial hypoplasia,
narrowed upper airways,49 or a large tongue. Alternatively, it may
delivery, use of forceps, size of the infant, use of regional anesthe-
sia, duration of pushing while in stirrups, or other details of the be secondary to a functional problem such as hypotonia of airway
obstetric course of these patients. muscles, which is seen in a generalized fashion in many achon-
droplastic dwarfs.49 Sleep apnea probably has an obstructive
While there are no studies to define the safety of regional
anesthesia in achondroplastic patients with spinal stenosis, the mechanical origin in these patients as opposed to a central etiol-
ogy.43 Other respiratory difficulties relate to neurologic problems.
implications of regional anesthesia in patients (not of short stature)
with spinal stenosis are outlined by Moen et al.41 In this study, the For example, foramen magnum stenosis causing compression of
incidence of paraparesis or cauda equina syndrome following neur- a normal-sized medulla can result in apnea and respiratory
embarrassment.42 Increased ICP in an achondroplastic dwarf
axial anesthesia was approximately 1:400 000 and 1:50 000 respect-
ively. However, all patients with paraparesis and almost one-third with hydrocephalus can also precipitate herniation through the
abnormally small foramen magnum.37,49,55
of patients with cauda equina syndrome were subsequently found
to have spinal stenosis. A full neurological exam and possibly ima- Occasionally, cor pulmonale occurs as a consequence of these
respiratory problems.2,49,56,57 However, corrective procedures
ging studies are recommended for achondroplastic patients. If the
patient has neurologic deficits, neurogenic claudication, and/or has performed early in childhood may reverse this process. Stokes
et al.49 described an achondroplastic child with upper airway
spinal stenosis without symptoms, she should be advised of the rare
but increased risk of neurologic injury associated with regional obstruction who experienced resolution of right-atrial and right-
anesthesia. If she has severe spinal stenosis, it may be advisable to ventricular enlargement after undergoing adenoidectomy and
avoid regional anesthesia, just as in individuals of normal stature. tracheostomy. Unfortunately, this problem is unlikely to be rever-
Foramen magnum stenosis due to bony hypertrophy is also a sible in patients with long-standing chest deformities and pul-
common finding in achondroplasia2 and can result in medullary monary hypertension who present for treatment while pregnant.
and upper-cervical neurologic deficits. Care must be taken to The nongravid achondroplastic dwarf has a reduced xiphoid to
limit hyperextension of the head in order to avoid exacerba- symphysis length as well as a decreased intercristal diameter (see
ting previous deficits and causing new cervical spinal cord Table 6.2). These decreased pelvic measurements, as well as the
injury.30,42,43,44,45 It is important for the anesthesiologist to ques- hyperlordotic features of achondroplasia, make the uterus an
tion the patient regarding neurologic symptoms prior to institu- abdominal organ even prior to pregnancy. Uterine enlargement
tion of GA or performance of direct laryngoscopy and intubation. during pregnancy occurs in an exaggerated anterior and superior
direction compared with parturients of normal stature.1 By the
Hypotonia and hydrocephalus are also features seen in
achondroplasia, although hydrocephalus does not always require fourth month, these patients appear to be in their 30th week of
ventricular shunting.2,33 Progressive hydrocephalus with concomi- pregnancy.1
tant elevations in intracranial pressure (ICP) may warrant shunting.
The mechanism for hydrocephalus in these dwarfs is thought to be
Pseudoachondroplasia
intracranial venous hypertension or cerebrospinal fluid (CSF) flow
obstruction at the level of the stenosed foramen magnum.46,47,48 Three cases of pregnant patients with pseudoachondroplasia
were noted in a survey of dwarfs.14 No mention was made of
In addition to the neurologic problems described above,
respiratory complications occur commonly. In one survey,14 4 anesthetic management or other complications encountered in



120
Chapter 6


previa19 and one received combined spinal“epidural (CSE)
these parturients. Patients with pseudoachondroplasia typically
anesthesia for elective C/S.62
present in early childhood, with similar stature to achondroplas-
tic dwarfs, but no craniofacial abnormalities. They may have
lumbar hyperlordosis, genu valgum (˜˜knock knees™™), genu varum
Effects of pregnancy
(knees are abnormally separated and the lower extremities are
bowed inwardly, i.e. bow leg),11 and scoliosis. As adults, they Life expectancy is diminished and infertility is common in
usually are less than 130 cm tall.2 patients with osteochondrodysplasias.1 However, pregnancy is
not uncommon, particularly in achondroplasia. Many of the con-
siderations related to pregnancy changes are the same as those
Nonachondroplastic dwarfism
described previously for proportionate dwarfs. However, because
Higher rates of spontaneous abortion, stillbirth, and premature of their abnormal upper airway and thoracic anatomy, dispropor-
delivery occur in nonachondroplastic dwarfs, as with dwarfs of tionate dwarfs have a greater risk of cardiac and respiratory com-
proportionate short stature.1 promise earlier in gestation.



Spondyloepiphyseal dysplasia Obstetric management
This is a rare form of dwarfism that is usually diagnosed at birth or There is some literature discussing obstetric concerns in this
population,14 but few reports describe anesthesia for preg-
in late childhood depending on the variant form. It arises either
from a spontaneous mutation, or may be of X-linked or autoso- nant osteochondrodysplastic dwarfs other than for achondro-
mal dominant inheritance.58 These patients have a short trunk plasts.4,59,62,63 Osteochondrodysplastic dwarfs are likely to need
with normal or shortened limb length and are usually less than C/S, because their babies are often of relatively normal size and
130 cm tall.2 The spondyloepiphyseal dysplasia congenita variant cannot be delivered safely through the small pelvis. Because
usually presents at birth and individuals may have short limbs,2,58 inadequate pelvic capacity and other abnormal pelvic configura-
whereas the spondyloepiphyseal dysplasia tarda variant is diag- tions prevent the head from engaging, breech and other malpre-
nosed in late childhood and limb length is usually normal.2 sentations are frequent, making C/S the most common mode of
delivery.1
Deformities in these patients include progressive kyphoscoliosis,
pectus carinatum (prominent sternum), platyspondyly (congeni-
tal flattening of the vertebral bodies), central anterior pointing of
Anesthetic considerations (see Table 6.5)
the vertebral bodies, genu valgum, talipes equinovarus (foot
deformity with plantar flexion of the foot and an inward turned General overview
heel), coxa vara (hip deformity with a decreased angle between Because disproportionate dwarfs are at such high risk for C/S, the
the femoral head and neck and the axis of the femoral shaft), and anesthesia service should be contacted early in gestation so that
odontoid hypoplasia.2,11,59 They may also have visual problems, appropriate evaluation can be performed and an anesthetic plan
retinal detachment, deafness, and cleft palate.2 Myer and developed prior to labor and delivery. A thorough history and
Cotton58 reported the presence of laryngotracheal stenosis in physical examination is essential, paying special attention to
two dwarfs with spondyloepiphyseal dysplasia. This is an impor- head, neck, and airway anatomy, the range of flexion and exten-
tant finding for the anesthesiologist should patients require GA sion of the neck, the presence of respiratory and neurologic signs
with the need for mask ventilation, direct laryngoscopy, and and symptoms, and anatomical landmarks on the back.
intubation. Odontoid hypoplasia can cause anterior dislocation If signs or symptoms of respiratory compromise are present,
of the first cervical vertebra producing spinal-cord compres- further investigations should be performed. Arterial blood gas
sion.60 The pelvis in this type of dwarfism is more contracted analyses, pulmonary-function testing, and chest radiographs may
than in achondroplasia, with markedly reduced xiphoid to sym- be helpful in prescribing appropriate therapy to optimize pulmon-
physis pubis and intercristal measurements (see Table 6.2).1 ary condition, as well as for use as a baseline for later in gestation
and the postpartum period.14,19 Some experts have recommended
that all chondrodysplastic dwarfs have cervical spine flexion and
Spondylometaphyseal dysplasia
extension radiographs prior to administration of anesthesia
This is an extremely rare form of short-trunk dwarfism.61 Features because of the high incidence of atlanto-axial instability and
other upper cervical vertebral anomalies.14,24 Certainly, nonachon-
of concern include progressive kyphoscoliosis with spinal-cord
compression, pectus carinatum, coxa vara hip deformity, con- droplastic disproportionate dwarfs should have these studies since
tracted pelvis with narrowing of the sacrosciatic notches, and a high percentage of them have C1 instability and the majority also
have a myelopathy.19,24,64,65 If symptoms suggesting spinal steno-
odontoid hypoplasia. Additionally, these patients may have cleft
palate, hemangiomas, inguinal hernias, congenital hydronephro- sis (e.g. neurologic symptoms or claudication) are present, ima-
sis, and mitral valve prolapse.19 Despite its rarity, two case reports ging should be performed to rule out this diagnosis.
exist of obstetric patients with this disorder. One received GA for Some authors have recommended GA for C/S, citing fears that
regional techniques may damage the spinal cord.14 However, the
C/S in the presence of hemorrhage and a marginal placenta



121
2 Musculoskeletal disorders


Anesthesia for achondroplastic parturients
Table 6.5 Anesthetic considerations for disproportionate
The current literature reveals several descriptions of anesthetic man-
dwarfs
agement for achondroplastic dwarfs.20,21,26,28,54,68,69,70,71,72,73,74,75,76
General and regional anesthesia both pose potential hazards in
Characteristics Anesthetic implications
these patients and the choice should be individualized to each
Airway
patient. The factors that increase anesthetic risk are detailed
Large head, tongue, and
in Table 6.5. Routine intraoperative monitoring is sufficient
mandible
for patients without pulmonary compromise. If respiratory
Maxillary hypoplasia Possible difficult mask airway/
embarrassment is present, an intra-arterial catheter assists in
Limited neck extension intubation
monitoring oxygenation, ventilation, and acid-base status. Two
Narrowed/obstructed upper May need smaller ETT size
reports have mentioned difficulty with the accuracy of noninva-
airways
sive blood pressure monitoring in achondroplastic dwarfs
Neurologic
because of their short, yet often obese, arms.21,69 In one instance,
Foramen magnum stenosis Possible neurologic injury with
intra-arterial catheter placement was necessary to accurately
laryngoscopy
measure blood pressure in a previously hypertensive parturient.69
Odontoid hypoplasia Consider flexion/extension
A serious concern is the risk of difficult intubation. The large
Atlanto-axial instability radiographs and/or awake
head with facial hypoplasia and a large mandible, limited neck
fiberoptic intubation
extension, and cervical instability are important considerations.25
Possible neurologic injury
While the majority of reports do not describe airway difficulties in
Musculoskeletal
achondroplastic dwarfs, there are enough cases of airway pro-
Spinal stenosis, lumbar Technically difficult regional
blems to mandate extreme caution.26,28 Awake direct laryngo-
hyperlordosis, anesthesia
scopy or fiberoptic laryngoscopy76 are options to be considered
thoracolumbar kyphosis, More prone to neurologic injury
when a GA is planned. One option is to evaluate the laryngeal view
short stature
preoperatively in the awake patient at a preoperative evaluation
Smaller epidural space Risk of dural puncture
using gentle direct laryngoscopy after application of topical
#Local anesthetic dose
anesthesia, and minimal sedation if needed.4,20 This may facil-
Small abnormally shaped pelvis High risk of cesarean section
itate the prediction of ease of intubation should it become neces-
Thoracic
sary in an urgent situation (when fiberoptic intubation would be
Chest deformities, hypoxia, Cardiac/respiratory
too time-consuming). If this examination is done in the operating
hypercarbia, obstructive compromise
room then intubation can be performed and GA induced immedi-
sleep apnea, cor pulmonale "Risk of respiratory ately thereafter. If a patient is suffering from pulmonary compro-
depression with mise prior to C/S, she may be unable to tolerate the supine position
parenteral and neuraxial opiates while awake. Additionally, rapid fluid loading administered prior to
Uterine impingement on May not tolerate supine position institution of regional anesthesia may not be well tolerated, so
intrathoracic structures and i.v. fluid administration fluids should be given cautiously rather than in large, prede-
Abdominal termined volumes. Individuals with significant pulmonary insuffi-
"Risk of aspiration
Early intra-abdominal uterine ciency may benefit from endotracheal intubation and mechanical
location ventilation during surgery and the postpartum period.
"Risk of supine hypotension As with proportionate dwarfs,24 ETT size is thought to be best
predicted in achondroplastic dwarfs by weight rather than age.25
same authors acknowledge that GA has ˜˜a higher risk of compli- However, most studies consist primarily of pediatric patients. In
cations compared with spinal and epidural anesthesia.™™14 In one the five adults intubated in the report by Mayhew et al.25 all
survey of 70 pregnancies in dwarfs, 63 patients were delivered by patients over the age of 17 were intubated with either a 7.0 or
C/S. The other 7 patients, all of whom had a chondrodystrophy of 7.5 mm cuffed ETT. In four case reports of GA for C/S in achon-
unknown etiology, were delivered vaginally. General anesthesia droplastic patients, a 6.5 mm ETT was used once, a 7.0 mm
was used in the majority of surgical cases, although 23 patients tube was used twice, and tube size was not reported in one
case.20,54,69,70 It seems prudent to have numerous ETT sizes avail-
received successful epidural anesthesia, 12 of whom were achon-
droplastic dwarfs.14 Regardless of the technique planned, it is able for the parturient dwarf as the airway changes induced by
important to remember that the uterus is an extrapelvic organ pregnancy, including airway edema, may necessitate the use of a
smaller than expected tube.13
in these patients and its enlargement increases the incidence and
severity of supine hypotension.20,21 Left uterine displacement, Regional anesthesia is a viable option in many achondroplastic
cautious intravascular fluid management, and prompt and patients, particularly if neurologic symptoms are absent. However,
aggressive pressor support after regional block are indicated. If a abnormal spinal anatomy may give rise to more patchy blocks and
GA is chosen, there is the increased aspiration risk present in all a higher rate of dural puncture, technical difficulty, and a greater
parturients undergoing GA, as well as additional risk secondary to potential for spinal-cord injury. Nevertheless, a regional anesthetic
uterine impingement on the dwarf™s abdominal contents.66,67 may be a better choice than GA for many individuals.14,15 In one



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Chapter 6



Table 6.6 Epidural anesthesia for achondroplastic dwarfs for cesarean section

Patient height & Epidural
weight level Local anesthetic Volume Sensory level Author Complication

122 cm L2“3 3% 2-chloroprocaine 9 ml T4 Cohen, 1980 Difficulty threading
þ 9 ml later
57 kg catheter.

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