Inhalation anesth for cs

Inhalation anestesia for caesarean
section :why?
How?
C.Melloni
Servizio di Anestesia e Rianimazione
Ospedale di Faenza(RA)
Servizio di Anestesia e Rianimazione Ospedale di Faenza(RA)

Changes in obstetric anesthesia(C/S) in USA(Hawkins et
al,Obstetric anesthesia workforce survey-1992 versus
1981.Anesthesiology 1994;81:A1128)

100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%

Epid
Spi
GA

1981

1992


Changes in obstetric anesthesia(C/S) in UK(Brown et al.Int
J.Obstet.Anesth.1995;4:214)

100%
80%
Epid
Spi
GA

60%
40%
20%
0%

1982

1987

1992


Number of deaths during cesarean section
Number of deaths during cesarean section

USA 1979-1990(Hawkins et al.Anesthesiology 86;280:1997)

1979-1984

1985-1990

GA

33

32

REG

19

9


Fatality rates during cesarean
Fatality rates during cesarean
section
section
per million of Ga or REG

1979-1984

1985-1990

G.A.

20

32.3

REG

8.6

1.9


Report on Confidential enquiries into maternal
deaths in England and Wales 1970-1996
Frequenza per milione di gravid.stimate
30

emb.polm
ipertens

25

anest

20
15
10
5
0

19 73- 76- 79- 82- 85- 88- 91- 9470- 75 78 81 84 87 90 93 96

emb.fluido amnio
aborto
gravid.ectopica
emorragia
sepsi
rottura utero
altre cause dirett

Entrata Faenza(RA)
Servizio di Anestesia e Rianimazione Ospedale di in vigore della nuova classificazione

Tsen LC, Camann W (2000) Training in obstetric general
anaesthesia: a vanishing art?Anaesthesia. 55:179-83


Topics
Indications
Contraindications
Side effects
Transplacentar passage:
» effects on the fetus and neonate
potentiating GA:reasons for:catecholamine reduction……
Crawford??
Obstetrical manoeuvers…
Emergency CS
Awareness avoidance—closed claims….
How:nearly all halogenated are equal…MAC properties
Side effects
Hypotension…but avoidance of aortocaval compression…
Nausea & vomiting


Indications for GA in OBS
Anesthesia personnel inexperienced in providing regional
anesthesia
Patient refusal of reg
Patient not cooperative
any istance of contraindications to regional anesth:
» infection:localized(dorsum) vs generalized(sepsis)….
» Coagulopathy:
emergency:foetal distress,placenta praevia,maternal haemorrhage,
urgent obstetrical manoeuvers …….
Hypovolemia….
Certain forms of heart disease that cannot tolerate
hypotension:fixed cardiac output;e.g.severe aortic
stenosis,Eisenmenger syndr.

Parekh N,Husaini SWU,Russell IFCaesarean section for
placenta praevia:a retrospective study of anesthetic
management.Br.J.Anaesth. 2000;84:723-30.

All anesth from 1 genn 1984 to 31/12/1998.
350 cases of plac previa:
» 60% Reg / 40% AG
» plc accreta;7 cases; 4 REG , 3 AG:but 2 reg convert.to
AG…5 hysterect.
» PA control during haemorrhage not a problem
» Ra assoc.with less blood loss
» “This retropectuve study do not support the often quoted
motto that plac.praevia calls for AG….”.

Disadvantages of GA
Asleep & unaware(late maternal bonding…)
husband less likely to be allowed in OR
drug depression of fetus
stress response to intubation
increased postoperative morbidity
cardiovascular changes of intubation
danger of aspiration(intubation & extubation)
difficult intubation

Ga:technique:I
Premed;antacids/H2 blockers/sodium citrate
LUD
ID/ UI-D intervals as short as possible
preoxygenation
(precurarization)
induction
cricoid pressure
Succi

Ga:technique:II
IOT
check lung expansion,bilat.
N20 50% + halog 0.6 Mac
after delivery:repeat hypnotic + analgesic;stop volatile
Oxytocin 10-20 UI/lt,drip…
extubate awake and cooperative,having ascertained
the full return of nm function…
plan for failed intubation

Indications for halogenated
anesthetics
potentiating GA:reasons
for:catecholamine reduction……
Crawford??

Reduction or avoidance of
maternal awareness,patient asleep
and unaware
optimum operating conditions

Side effects
Haemodynamics derangement
uterine atonia…


Halogenated
agents:advantages..
allow use of increased O2
concentrations
may increase uterine blood flow by
decreasing maternal catecholamine
mediated uterine artery constriction
prevents awareness…but a few minutes
are needed before the attainment of a
reasonable MAC…(sevorane or desflurane
more rapid equilibration!

Halogenated
agents:diasdvantages..
Uterine bleeding
low apgar scores?
Low neuroehavioral examinations
theatre pollution...


Modifications that affect inhalation
anesthesia in pregnancy
pain and discomfort thresholds
MAC requirements 25%‑40%.
FRC


Transfer time


Mac and pregnancy
Mac for inhalational agents decresed by
pregnancy(Datta et al,Chronically
administered progesterone decreases
halothane requirements in
rabbits.Anesth.Analg. 1989;68:46-50)


Chan et al.
Minimum Alveolar Concentration of Halothane and
Enflurane Are Decreased in Early Pregnancy Anesthesiology
85:782-6, 1996


MAC reduction in pregnancy
Gin T, Chan MTV: Decreased minimum alveolar concentration of isoflurane in pregnant humans.
ANESTHESIOLOGY 81:829-32, 1994 ;& Chan et al.
Minimum Alveolar Concentration of Halothane and Enflurane Are Decreased in Early Pregnancy
Anesthesiology 85:782-6, 1996

1,8
1,6
1,4
1,2
1
0,8

isoflurane
halothane
enflurane

0,6
0,4
0,2
0

non pregnant

pregnant


Avoid maternal
hyperventilation


King H, Ashley S, Brathwaite D, Decayette J,
Wooten D: Adequacy of general anesthesia for
cesarean section. Anesth Analg 77:84-8, 1993

68-130 sec

3min

2min

inc

1 min

ind

skin inc

Lifescan
finger flexion
hand squeeze
lacrimation

lryngoscopy,IOT

120
100
80
% of
60
patients
40
20
0

Isolated arm technique

delivery
220-367 sec.

Tps/scc/iot/N2O 50/haloth 0.5%


Characteristics of inhaled
anesthetics
agent

mw

MAC

Boling
point

Vapor
press.

Blood/gas
partition
coeff.

pungency

Soda lime

desflu 168
rane
N2O
44

6

23.5

663

0,42

yes

stable

105

-88

no

stable

sevofl
urane
isoflur
ane
enflur
ane
haloth

200

2.0

58.5

39000 0,47
gas
160
0,60

no

decomposes

184,5

1.15

48.5

238

1.4

184,5

1,68

56.5

175

1,9

197,4

0,75

50,2

241

2,4

moder Stable
ate
moder Stable
ate
none Decomposes


Rise in alveolar(Fa) anesthetic concentration toward
the inspired(Fi) concentration


Navarro EM.Desflurane general anesthesia for cesarean
section compared with isoflurane and epidural
anesthesia.Anesthesiol.Intensivmed.Notfallmed.Schmerzther
2000;35;232-6.

Desflurane 2.5% vs isofl 0.5% vs epid 15 ml ropi
0.75% + fent 100 microgr
N2O 50%
intraop haemodynamics
blood loss
maternal awareness
Apgar scores 1-5 min
NACS 2-24 h
Ega UV/MV

Navarro II
No diff among the 3 groups except a
more rapid emergence following des.


Olthoff D,Rohrbach A. Sevoflurane in obstetric
anesthesia.Anesthesist 1998;47,suppl 1,s 63-9

Sevo > isofl and no outcome diff with
epid,
sevo> isof in pEEG monitoring……...


Transplacentar passage


Attenuation of catecholamine
responses……..


Shnider et al: Uterine blood flow and plasma norepinephrine
changes during maternal stress in the pregnant ewe.
ANESTHESIOLOGY 50:524-7, 1979
Electrically induced stress 30-60 sec,
loud noises,sudden movement of personnel...

60
40
20
% change
from
basal

0
-20

1

2

3

4

5

-40
-60
-80
min


MAP
Norepi
uter.Blood flow

Uterine blood flow changes during
anesth.in the pregnant ewe(from
Shnider,Levinson,etc..)

20
15
10
5
% change from
0
control
-5
-10
-15
-20

N2O 50%
N2O 50% +haloth 0.5%
N2O 50% + enfl 1%

anest without stim

anest with
stimulation


Maternal awareness of surgery and birth
after barbiturate-relaxant induction &...
20
18
16
14
12
% 10
8
6
4
2
0

N2O 50%
N2O 67-75%
N2O 25-40%+halo
0.4%
N2O 50%+haloth
0.3%
N2O 50%+enfl 0,75
N2O 33%+metx 0.1%
maternal awareness

N2O 50+ isof 0,75%


Lyons G, Macdonald R: Awareness during caesarean section.
Anaesthesia 46:62-4, 1991

1982-1989
> 3000 patients
questioned about recall and dreaming after general
anaesthesia for Caesarean section
28 (0.9%) patients were able to recall something of
their operation
189 (6.1%) reported dreams. Recollections of surgery
were confined to manipulations, noises and voices.
None of our patients complained of pain at the time of

Incidence of awareness(from various
sources)

16
14
12
10

C/S
card.surg
non card. Surg
major trauma

% 8
6
4
2
0

0.4
incidence


Domino K, Posner KL, Caplan, R,Cheney F. Awareness
during Anesthesia : A Closed Claims Analysis.Anesthesiology
90:1053-61, 1999.

Liability risk


Closed claim database for
intraoperative awareness
79 over 4183 claims;1.9% :
» 18 claims for awake paralysis(inadvertent paralysis of
an awake patient
» 61 claims for recall during GA :recall of events while
receiving general anesthesia


Awareness claims
1.9% of all claims
awareness, defined as being paralyzed
while awake or awake while receiving a
general anesthetic, were reviewed. These

claims were further divided into two
categories: awake paralysis, i.e., the
inadvertent paralysis of an awake
patient, and recall during general
anesthesia, i.e., patient recalled events
while receiving general anesthesia.

Closed claim database for
intraoperative awareness
The majority of awareness claims involved :
»
»
»
»

women (77%)(OR 3.21)
younger than 60 yr of age (89%)
ASA I—II (68%)
who underwent elective surgery (87%),obs/gynecol.

Claims for recall during general anesthesia were more likely to
involve :
» women (odds ratio [OR] = 3.08, 95% confidence interval [CI] = 1.58, 6.06)

anesthetic techniques using intraoperative opioids (OR = 2.12, 95%
CI = 1.20, 3.74)
intraoperative muscle relaxants (OR = 2.28, 95% CI = 1.22, 4.25)
and no volatile anesthetic (OR = 3.20, 95% CI = 1.88, 5.46).

Dwyer R, Bennett HL, Eger EI II, Peterson N: Isoflurane
anesthesia prevents unconscious learning. Anesth Analg
75:107-12, 1992

Several authors report prevention of conscious recall
of events by relatively small concentrations of volatile
anesthetics. Isoflurane in concentrations of 0.6 MAC

prevented conscious recall and
unconscious learning of factual information
and behavioral suggestions.


Ranta S, Laurila R,Saario J,Ali-Melkkilä T, Hynynen M.
Awareness with Recall During General Anesthesia: Incidence
and Risk Factors Anesth Analg 1998; 86:1084

4818 operations under GA: 2612 (54%) patients were
interviewed
10 (0.4% of those interviewed) patients were found to
have undisputed awareness
9 (0.3%) patients with possible awareness.
The doses of isoflurane (P < 0.01) and propofol (P <
0.05) were smaller in patients with awareness.
5 patients with awareness underwent a psychiatric
evaluation;possible associtation with depression.

Moir, D. D .ANAESTHESIA FOR CAESAREAN SECTION An
Evaluation of a Method using Low Concentrations of Halothane
and 50 per cent of Oxygen Br. J. Anaesth. 1998; 80:690-696

The addition of 0.5 per cent of halothane vapour to a
basic thiopentone, nitrous oxide, muscle relaxant
anaesthetic technique does not increase blood loss at
Caesarean section, does not affect the incidence of
hypotension, and is likely to ensure unconsciousness.
By permitting the administration of 50 per cent of
oxygen with nitrous oxide, the condition of the
newborn infant is likely to be improved. The use of 0.8
per cent of halothane vapour does not increase blood
loss but is associated with a high incidence of

Elective C/S:Duration of GA or Epidural antepartum and % of
Apgar scores between 7-10

100
90
80
70
60
% 7-10
50
Apgar scores
40
30
20
10
0

(da dati di Robin,Shnider,Levinson---)

Min:
<5
6;10
11;20
21;30
31;60
GA

epid


I-D & UI-D
But more importantly than overall
duration between induction and delivery
(I-D) is the
uterine incision-delivery interval(UI-

D),that has been shown to correlate
with fetal hypoxia and acidosis

GA and neonatal depression
100
90
80
70
60
50
40
30
20
10
0

spinal
epidural
GA

Apgar 1'

Apgar 5'


Fetal-neonatal effects of
halogenated vapours
ONG BY,Cohen MM,Palahniuk
RJ:Anesthesia for cesarean section:
effects on neonates.Anesth.Analg
1989;68:270-275.
Greater requirements for neonatal
intubation and resuscitation versus
regional block in urgent C/S

Ong BY,Cohen MM,Palahniuk RJ.Anesthesia for cesarean
section:effects on neonates.AA 1989;68:270-5.

3940 C/S;12.5% of neonates Apgar < 4
1.5% 5 min Apgar score < 4
list of factors associated with low 1 min Apgar scores:
primiparity
grand multiparity
antepartum disease(preeclampsia,diabetes mellitus,maternal heart disease RH
isoimmunization, early amtepartum haemorrhage)
presence of fetal distress
low gestational age
use of narcotics during labor
breech presentation
nonelective C/S


Ong et al.Anesthesia for cesarean

Multivariate analysis that controlled for
many variables gave:
Higher risk of low apgar at 1 min GA 3
>reg(2.5-3.88)
Higher risk of low Apgar at 5 min; GA 3>
reg(1.81-7)
need for resuscitation: GA 2> reg(1.322.90)

Neonatal outcome after C/S by anesthetic technique:infants
with 1 min Apgar score < 4 (%)

Ong BY,Cohen MM,Palahniuk
RJ.Anesthesia for cesarean section:effects on neonates.AA 1989;68:270-5.

0.01

45
40
35
30

elective
0.001

25

fetal distress
failure to progress

20
15
10

0.05

5
0

reg

GA


Infants with 5 min Apgar score 0-4(%)



0.01

9
8
7
6
5

0.01

4
3
2

elective
fetal distress
failure to progress

1
0

reg

GA


Neonates requiring oxygen by mask(%)


0.001

25
20

0.01

15

elective
fetal distress
failure to progress

10
5
0

reg

GA


Neonates requiring iot and IPPV(%)


0.001

45,0
40,0
35,0
30,0

elective
fetal distress
failure to progress

25,0
20,0
15,0
10,0
5,0
0,0

reg

GA


Gregory FA, Wagde JG, Biehl DR, Ong BY, Sitar DS. Foetal anaesthetic
requirements (MAC) for halothane. Anesth Analg 1983;62:9 ‑ 14.
Bachman CR, Biehl DR, Sitar DS, Cumming M, Pucci W. Isoflurane potency and
cardiovascular effects during short exposures in the foetal lamb. Can Anaesth Soc
J 1986;33:41‑ 7.

MAC is significantly lower in fetal lambs
than in lambs more than 24 hours of age.
These findings suggest that neonates
immediately after birth may be quite
sensitive to inhalation anesthetics so that
those exposed to general anesthetic agents
may be less vigorous at birth. After assisted
respirations and expiration of the anesthetic
agents, these infants appear to resemble
other infants,

Neonatal deaths

Ong BY,Cohen MM,Palahniuk RJ.Anesthesia for cesarean

7
6
5
4

elective
fetal distress
failure to progress

3
2
1
0

reg

GA


Postpartum blood loss:Piggott SE,Bogod DG,Rosen M,Rees
GAD,Harmer M.Isoflurane with either 100% oxygen or 50%
nitrous oxide in oxygen for caesarean section.BJA 1990;65:32529.
0,0
-5,0
HB decrease,
%

-10,0
-15,0

elective
emergent

0% +
1,2%

0% +
ur 1,7

00%+
loth
,75

-25,0

2O
aloth
.5

-20,0


Influence of anesthesia on blood loss at C/S(Moir DD.Anesthesia for
cesarean section:an evaluation of a method using low concentrations of halothane and 50% of
oxygen.BJA 1970;42:136-142.

800
700
600
500

N2O 70
N2O50+ aloth 0,5
N2O 50+ haloth 0,8
epid analg

ml 400
300
200
100
0

blood loss


HCT values before and after C/S:(from Thirion et al.Maternal blood loss

associated with low dose alothane administration for caesarean section.Anesthesiology
1988;69:a693)

40
35
30
25
%

Hct preop
HCTday 1
Hct day 2

20
15
10
5
0

haloth
predelivery

aloth pre& post

epidural


Conclusions for halog agents
and blood loss
Dose related decrease in uterine
contractility and tone
but no increase in blood loss if used in
low-moderate concentrations:

haloth 0.1-0.8
enflurane 0,5-1,5
isoflurane 0,75
sevoflurane…..


In every case,after delivery of
the neonate…...
Stop the volatile anesthetic
continue N2O(increase to 60-65%)
administer a IInd dose of hypnotic(TPS
100-150 mg;propofol 60-100 mg +
a potent analgesic:fentanyl 100-150
microgr..…
nmb if needed

Wojtczak, Jacek A., MD, PhD
The Hemodynamic Effects of Halothane and Isoflurane in
Chick Embryo Anesth Analg 2000; 90:1331
The cardiovascular effects of volatile anesthetics in
prenatal hearts are not well investigated. The purpose
of this study was to determine whether the embryonic
cardiovascular system is sensitive to an exposure to
clinically relevant, equipotent concentrations of
halothane and isoflurane. Stage 24 (4-day-old) chick
embryos were exposed to 0.09 and 0.16 mM of
halothane and 0.17 and 0.29 mM of isoflurane. Dorsal
aortic blood velocity was measured with a pulsedDoppler velocity meter. Halothane,

but not
isoflurane, caused a significant
decrease in cardiac stroke volume and

Effect of halothane on stroke volume and
acceleration of aortic blood in chick embryos


Effect of isoflurane on stroke volume and
acceleration of aortic blood in chick embryos


Biehl DR, Tweed A, Cote J, et al. Effect of halothane on
cardiac output and regional flow in the fetal lamb in utero.
Anesth Analg 1983; 62:489-92

We studied the effect of halothane on
the fetal cardiovascular system of six
lambs in utero by measuring fetal heart
rate and femoral arterial blood pressure
and by injecting labeled microspheres
during a control period and again after
60 and 90 min of halothane anesthesia
administered to six pregnant ewes at an
inspired concentration of 1.5%. There
were no significant effects on maternal

Biehl et al. Effect of halothane on cardiac
output and regional flow in the fetal lamb in
utero. Anesth Analg 1983; 62:489-92
Halothane 1.5%
30
20
10
% change from 0
control
-10

MAP
HR
heart BF
brain BF

-20
-30
-40

*

*
8

*
16

*
32

*
60

96

min


Bachman CR, Biehl DR, Sitar D, et al. Isoflurane potency and
cardiovascular effects during short exposure in foetal lamb.
Can Anesth Soc J 1986; 33:41-7

Isoflurane is a relatively new volatile
anaesthetic in clinical practice and
increasing use for obstetrical patients
might be expected. A previous study
demonstrated that a 60-90 minute
exposure of the foetus to isoflurane
resulted in a significant fall in foetal
cardiac output with development of
foetal acidosis. To determine the
cardiovascular effects Ospedale di Faenza(RA)
Servizio di Anestesia e Rianimazioneof a shorter

Baum VC, Palmisano BW. The immature heart and anesthesia.
Anesthesiology 1997; 87:1529-48

volatile anesthetics inhibit myocardial
function by depressing systems in
addition to ICa,L even in neonatal
myocardium. Baum and Wetzel showed
that halothane, in clinically relevant
concentrations, reversibly inhibits Na+—
Ca2+ exchange in neonatal ventricular
myocytes. This provides an additional
mechanism that may be responsible for
the more pronounced depression by

Baum VC, Palmisano BW. The immature heart and anesthesia.
Anesthesiology 1997; 87:1529-48

Halothane and isoflurane prolong AV
conduction time directly.
Anesthesia and O2 Consumption and
Metabolism
In vitro, halothane and isoflurane
increase coronary flow in a dose-related
manner in infant rabbit and fetal lamb
hearts. In the isolated heart preparation
in which coronary perfusion pressure is


Baum VC, Palmisano BW. The immature heart
and anesthesia. Anesthesiology 1997; 87:152948

In the neonatal lamb undergoing
hypoxic stress, neither halothane nor
isoflurane alter redistribution of blood to
vital organs, including the heart. In
addition, myocardial blood flow in the
neonatal lamb decreases significantly at
1 MAC isoflurane (from 250 to 88
ml×100 g-1×min-1), but in exact
proportion to Rianimazione Ospedale myocardial
the decrease in di Faenza(RA)
Servizio di Anestesia e


In neonatal rabbit hearts studied in vitro
with 1.5% halothane, McAuliffe and
Hickey found no change in steady-state
levels of high- energy phosphates or
intracellular pH, despite a 50%
decrement in mechanical performance.
Significant uncoupling of oxidative
phosphorylation cannot account for
halothane's depressant effect on
systolic function in the Ospedale di
Servizio di Anestesia e Rianimazione neonate.Faenza(RA)


Anesthesia and Systolic Function
The effects of the inhalational
anesthetics in intact immature hearts
have been evaluated in several studies.
Although one study suggested that the
apparent increase in hemodynamic
depression in the young heart in human
studies may be a result of differences in
anesthetic uptake and distribution, other


Summary
Immature hearts are more profoundly
affected by many anesthetics than are
adult hearts. Maturational changes in a
variety of cellular and subcellular
systems and influences of the
autonomic nervous system may be
responsible, but as yet, specific
mechanisms remain to be elucidated.

Brett CM, Teitel DF, Heymann MA, Rudolph AM: The young
lamb can increase cardiovascular performance during
isoflurane anesthesia. ANESTHESIOLOGY 71:751-6, 1989

Cardiac output and myocardial blood
flow decrease dramatically in a dosedependent pattern in the young lamb
during isoflurane anesthesia. This raises
important questions about the ability of
the young lamb to increase myocardial
performance if oxygen delivery were
compromised by a decrease in oxygen
content during anesthesia and surgery.
To investigate the ability of the young


Coagulation and anesthesia
The Effect of Anesthetic Techniques on
Blood Coagulability in Parturients as
Measured by Thromboelastography
Sharma, Shiv K., MD, FRCA; Philip,
John, MD
: Anesthetic techniques may affect
blood coagulability and the subsequent
incidence of thromboembolic events.
The purpose of this study was to


Interactions of volatile agents
with:
nifedipine;enhancement of
haemodynamic side effects with
aloth,enfl,iso(but non pregnant
animals…)..(and Rosone et
al..Hemodynamic responses to
nifedipine in dogs anesthetized with
halothane. Anesth.Analg 1983;62:903908.)
nicardipine enhancement of uterine

“Progesterone Decreases the MAC of
Desflurane in the Non Pregnant Ewe,”
was presented by Thompson and
collaborators, Ochsner Clinic, New
Orleans. They noted that the minimum
alveolar concentration for pregnant
ewes and that for nonpregnant ewes
treated with progesterone were similar.
The minimum alveolar concentration of
desflurane in untreated nonpregnant

Inhalational anesthetics with a rapid
equilibration between inspiratory and
end tidal concentraions,i.e less
soluble,should provide the correct
answer…..


the maternal and neonatal effects of
hsalothane,enflurane and isoflurane for cesarean
delivery.Anesth.Analg 1983;62:516-520.


Datta et al.Maternal and fetal catecholamines and uterine
incision-delivery interval during elective cesarean
section.Obstet.Gynecol 1990;75:600-603.


Neurobehavioral examination
Results more depressed(albeit subtle) in
neonates born from GA than reg….
(Shnider 238 pagg…)


Wallace DH et al.Randomized comparison of regional and
general anesthesia for cesarean delivery in pregnancies
complicated by severe preeclampsia.Obstet Gynecol
1995;86,193-


Gin T, Chan MTV: Decreased minimum alveolar
concentration of isoflurane in pregnant humans.
ANESTHESIOLOGY 81:829-32, 1994

<AB - BACKGROUND: Minimum
alveolar concentration (MAC) is
decreased in pregnant animals, but this
change has not been demonstrated in
humans, probably because of ethical
considerations. It is less problematic to
determine MAC in pregnant women
undergoing termination of pregnancy,
however, and therefore we compared
the MAC of e Rianimazione Ospedale di Faenza(RA)
Servizio di Anestesia isoflurane in these women

Chan M,Mainland P, Gin T
Minimum Alveolar Concentration of Halothane and
Enflurane Are Decreased in Early Pregnancy Anesthesiology
85:782-6, 1996

The MAC of halothane and enflurane
were compared in pregnant women
undergoing elective termination of
pregnancy and in nonpregnant women.
Methods: We studied 16 pregnant
women scheduled for termination of
pregnancy at 8 to 13 weeks gestation
and 16 nonpregnant patients
undergoing laparoscopic sterilization.

cardiovascular and metabolic effects of halothane in normoxic
and hypoxic newborn lambs. ANESTHESIOLOGY 62:732-7,
1985

Oxygen consumption, cardiac output,
and tissue oxygen delivery were
measured in normoxic and hypoxic 1-3day-old lambs during the following six
conditions: 1) (control) paralysis with
pancuronium and controlled ventilation
with room air; 2) paralysis, controlled
ventilation and hypoxia (PaO2 = 30 +/- 3
mmHg, [SD]); 3) paralysis, controlled
ventilation with room air and 0.5 MAC

Effects of halothane anesthesia 0.5 & 1
Mac in normoxic and hypoxic lambs

(Cameron

et al. The cardiovascular and metabolic effects of halothane in normoxic and hypoxic newborn lambs.

normoxia
1 mac

normoxia
0.5mac

hypoxia
1 mac

hypoxia
0.5mac

300
250
200
150
mean %
100
change
from control 50
0
-50
-100

hypoxia

ANESTHESIOLOGY 62:732-7, 1985)


O2 cons
CO
HR
MPAP
PVR
lactic acid
Norepi
Epi
SVR

Inhalation anesth for cs

Recomendados

Recomendados

Mais conteúdo relacionado

Destaque

Destaque (20)

Semelhante a Inhalation anesth for cs

Semelhante a Inhalation anesth for cs (20)

Mais de Claudio Melloni

Mais de Claudio Melloni (20)

Último

Último (20)

Inhalation anesth for cs