Title: Obstetric anesthesia for the obese and morbidly obese patient: an ounce of prevention is worth more than a pound of treatment
1Obstetric anesthesia for the obese and morbidly
obese patient an ounce of prevention is
worth more than a pound of treatment
- Soens MA, Birnbach DJ, Ranasinghe JS, van Zundert
A. - Acta Anaesthesiol Scand. 2008 Jan 52(1) 6-19.
2- Maternal and fetal morbidity
- Pregnancy, obesity and physiology
- Anesthetic management of the obese parturient
- Analgesia for labor
- Continuous lumbar epidural analgesia
- Combined spinal epidural (CSE) anesthesia
- Continuous spinal analgesia
- Anesthesia for cesarean delivery in the obese and
- morbidly obese patient
- Regional anesthesia
- General anesthesia
- Post-partum morbidity
3Maternal and fetal morbidity
- Obesity? ?? complications
- Diabetes mellitus, hypertension, coronary
artery disease, cerebrovascular disease, and
gallbladder and liver disease. - pre-pregnancy maternal obesity? ??
- pregnancy-induced risk
- hypertension, venous thromboembolism, labor
induction, cesarean delivery, gestational
diabetes , large-for-gestational age fetuses,
fetal macrosomia, neural tube defect(such as
spina bifida), difficult ultrasono-exam. and
wound infection.
4Pregnancy, obesity and physiology
- ???? sensation of dyspepsia
- Uterus? respiratory function? ??? ??? ??? ??
- ?? 5?? ??
- Progressive decrease in expiratory reserve
volume, residual volume, - fuctional RV ? Increased risk for
obstructive sleep apnea - associated
with systemic HTN, pulmonary HTN - importance of pre-oxygenation
- Increased risk for coronary artery disease,
stroke, cardiac arrhythmia - Increased risk for aspiration(Mendelsons
syndrome) lower gastric pH - Increased risk for difficult or failed intubation
5Anesthetic management of the obese parturient
- Analgesia for labor
- Continuous lumbar epidural analgesia
- Combined spinal epidural (CSE) anesthesia
- Continuous spinal analgesia
6Analgesia for labor
- Fetal macrosomia? incidence? ???? painful
contraction? complicated labor? ???? ??. - BMI vs Severity of labor pain A positive
correlation (Melzack et al.) - Regional analgesia many advantages in the
obstetric patient, - BUT difficult anesthetic
technique in the obese parturient. - General anesthesia for c/sec much higher risk of
maternal mortality - as compared with regional
anesthesia. (Hawkins and colleagues) - ?? ??? Maternal death claims? ?? ??? ?? ?? ??? ??
- ? ???? ??. (The 1991 ASA Closed Claim Study)
- The incidence of failed intubation in the
morbidly obese parturient -
High as 33 - The American College of Obstetricians and
Gynecologists (ACOG) - ??? ??? ??? ???? ?? ???? functioning epidural
or spinal catheter? ???? ?? ?? ?? ??.
7Continuous lumbar epidural analgesia
- Anatomical landmarks? ??? ?? epidural placement?
- morbidly obese patients? ??? often difficult.
- Jordan et al.? ??? 1? ??? ??? ??? ??? 74.4??
- 3? ?? ? ??? 14?
???. - ?? accidental dural puncture? incidence? 4(in
morbidly - obese parturients)? ???? ??(0.52.5 in
non-obese patients) - ?? ??.
- 1) The patient position? Catheter insertion
- (1) lateral recumbent head-down position
- decrease the incidence of
intravascular placement - by reducing venous congestion in
the epidural veins - (2) sitting position
- the line joining the occiput or
prominence of C7 and the - gluteal cleft can be used to
approximate the position of - the midline.
8Continuous lumbar epidural analgesia
- 2) Distance from the skin to the epidural space
- (1) significantly shorter in the sitting
position - (compared with the lateral decubitus
position. (Hamza et al.) - (2) Hamza et al. also epidural space??? ???
weight? BMI - ?? positively
correlation? ???. - (3) HOWEVER, Watts? BMI is a poor predictor of
distance to - the epidural space compared with the
non-obese group. - (4) Only a few patients have an epidural space
deeper than - 8cm (Hamza J et al.)
-
- Standard epidural needle for the first
attempt, - instead of one of the longer epidural
needles available.
9Continuous lumbar epidural analgesia
- 4) Identify the midline of the spine
- (1) Morbidly obese patients? ???, identify
the midline?? - ?? ?? tool? ?? ?? ?? ??? ? ? ??.
- whether she feels the needle more on the
left or the right - side of the spine-gt most accurate, with
90 of the - volunteers able to identify the midline
to within 6.5 mm. -
( In a pilot study by
Wills et al.) - (2) Ultrasound guided approach?
- Grau et al.? paramedian longitudinal
approach? ??? ??? - ?, ???? ??? transverse approach? ? ??? ??.
10Continuous lumbar epidural analgesia
- 5) Correct epidural catheter placement
- (1) 3 cm skin movement in some patients,
epidural catheters - ? walk? ???? routinely place
catheters 7 cm in the - epidural space (Iwama and Katayama)
- (2) Epidural catheters? ????? ?? skin? ????
?? - inward?? 12.5cm ?? ??? ? ??? BMIgt30?
?? - ? ? ?? ????? ?????. (Hamilton et al.)
11Combined spinal epidural (CSE) anesthesia
- Compared with classical epidural,
- CSE provides a faster onset of effective pain
relief, - and increases patient
satisfaction. - However, intrathecal opioids? ???? ?? incidence
of uterine hyperactivity and fetal heart rate
abnormalities? ???? ??. controversial. - Due to increased abdominal pressures,
- lower epidural analgesic requirements in obese
parturients - (compared with normal patients).
12Continuous spinal analgesia
- Relatively high failure rate of epidural
catheters in the obese population (accidental
dural puncture), ???? often prefer intentional
continuous spinal analgesia/anesthesia? ????? ??. - ONE possible complication of the continuous
spinal - technique post-dural puncture headache
(PDPH), - occurring in 3070 of obstetric patients
following accidental - dural puncture with a 17 gauge Tuohy needle.
- Faure et al.? the risk of PDPH is significantly
decreased in - morbidly obese parturients. (because of
?elevating intra- - abdominal pressures and ?reducing the degree
of spinal fluid - leakage through the dural puncture site)
- ????? CSA? incidence of spinal headache?
1????. - Catheter insertion 24 cm in the subarachnoid
space.
13Anesthesia for cesarean delivery in the obese and
morbidly obese patient
- Obesity significantly increases the incidence
of cesarean delivery. - Nulliparous patients a cesarean delivery rate
(Weiss et al.) - -20.7 in the control group
- -33.8 in the obese
- -47.4 in the morbidly obese group
- Obesity in maternal mortality, morbidity and
operative Cx. - - Excessive blood loss
- - Increased operative time
- - Increased incidence of post-operative
wound infection and - endometritis.
14Anesthesia for cesarean delivery in the obese and
morbidly obese patient
- morbidly obese parturient? ?? ? ??
- ?? ? ??? ??? ??? ??? ?? ??? ??? ????,
- ????, panniculus retraction, thromboembolism
- prophylaxis, type and cross match,
post-operative care and - overnight monitoring in an intensive care
unit and possible - comorbidities and their consequences?? ?? ???
??. - (2) ????
- (a) two operating tables (side by side)
- impossible to raise, lower or change
the position of the - tables in a completely synchronous
manner. - (b) use one set of armboards
- (3) the morbidly obese parturient? ??
- (a) regional anesthesia? ???? ??? ??
- position?? ??? ??
- (b) sleep apnea? ?? ?? ? ? CPAP? ????? ??.
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17Anesthesia for cesarean delivery in the obese and
morbidly obese patient
- The pre-operative initiation of CPAP in
patients with severe obstructive sleep apnea, as
this may improve their preoperative condition
(The ASA Practice Guidelines for the
Perioperative Management of Patients with
Obstructive Sleep Apnea recommend). - Risk factor for venous thromboembolism
- ?
prophylaxis should be considered. - Difficulty with non-invasive blood pressure
monitoring - radial intra-arterial catheter may be
preferable, - especially in patients with comorbidities such
as chronic hypertension and preeclampsia.
18Regional anesthesia
- ?? ??? ?? ?? ?? ??????? ??? ?? ????? high
spinal block? ???? ??. - 1) Lower average CSF volume with a high BMI
- decreased local anesthetic dose
requirements in obese - patients due to decreased anesthetic
dilution - 2) External abdominal compression and abdominal
pressure - 3) Compression of the dural sac due to
engorgement of the - epidural venous plexus and increased
epidural space pressure
19Regional anesthesia
- Spinal anesthesia? c/sec?? ?? ??? ????
- ??? ?? ??? ?? ??? ?? risk? ??.
- 1) Risk of a high spinal block.
- 2) ??? ??? ? ??? ???? ??? ??? ? ??.
- ??? ??? ??? ??? ??? ? ???
- 25??? ?? ???? ??? ????? ?? ? ??.
- CSE technique lower doses of local
anesthetics?? - (compared with a
single-shot spinal technique) -
- CSA catheter allows incremental dosing and
precise extension of - the block
- ?? ? Inadequate block?? ?? ????? ?? ? ??? ????
- ???? catastrophic sequelae? ??? ? ??.
20General anesthesia
- Prevention of acid aspiration
- 1) ??? ?????, ?? ?? 30??? antacid??
- 2) ??????????, ??? ????? ?? ??? ?? 60-90
- ??? H2 antagonist(ex. ranitidine) or
- a proton pump inhibitor(ex.
Omeprazole) ?? - 3) ???? ?? ??? ??? ?? ??? ??
- prokinetic agent? metoclopramide? ?? ???
?? ??. - Difficult airway? ??? ?? ??.
- 1) ??, a large neck circumference and/or
- a high Mallampati score
- 2) ??? mask ventilation??? ??? ? ??.
21General anesthesia
- Preoxygenation(denitrogenation) before
induction of G/A - 1) (m/c method) 35min of 100 O2 breathing.
- 2) 4 maximally deep inspirations of 100 O2
within 30 s - 3) 8 deep breaths within 60 s at an oxygen flow
of 10 L/min - (more suitable for obstetric emergencies)
- Position
- 1) Pre-oxygenation? sitting? more effective
- 2) failed intubation? ???? ?? ??? rapid
sequence - induction with cricoid pressure ??
- 3) elective??? awake fiberoptic intubation? ??
- 4) fail???? ???? LMA? ??
- 5) the ramped position improves the
laryngeal view
22General anesthesia
23General anesthesia
24General anesthesia
25General anesthesia
- ????? ????? ??
- Oebsity blood volume, cardiac output and muscle
mass? ?? - 1) Thiopental higher initial induction dose,
but ????? - ????? failed Intubation?
??? ???? - 2) Propofol ??? initial distribution volume?
??? ??. - 3) Succinylcholine choice for intubation in the
obstetric patient. - 4) ?? ??? obese patient? ?? ???? O2? ??? ??.
- ( ???? N2O??? ???.)
- 5) Desflurane faster recovery time ? higher
oxygen saturations on entry in the recovery room
(compared with sevoflurane) - 6) ?? ? ??? ???? ??? ?? midazolam? ??? ???
- ??? ? ??.
- 7) In obesity, lipophilic???? Prolonged
sedation? ? ???? - fully awake? ???? ?? ??.
- semi-upright position
- abdominal contents? ?? diaphragm? compression?
??
26Post-partum morbidity
- Post-partum complications
- hemorrhage, endometritis, wound infection,
respiratory depression, deep venous thrombosis,
pulmonary embolism, hypoxemia - 1) Increased risk of endometritis and wound
infection - ? prophylactic antibiotics after clamping the
umbilical cord. - 2) Increased risk of respiratory depression and
hypoxemia - ? Semirecumbent position, early mobilization
and adequate pain - control (early resolution of atelectasis
and a faster recovery of - pulmonary function.)
- 3) Increased risk for venous thromboembolism
- ? low molecular-weight heparin (LMWH) therapy
- (1) European guidelines single daily dosing
of LMWH - - catheters remove 1012 h after the
last dose of LMWH - and 4 h
before the next dose - (2) United States guidelines twice-daily
dosing of LMWH - - catheters remove 2 h before the
first - and the first
dose should be 24 h after surgery. - 4) opioids? risk for respiratory depression? ??
???? ??