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7/27/2019 Obat Anastesi Pada Kehamilan

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Anaesthesia in pregnancy


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Incidence

0.3% to 2.2% of pregnant women undergosurgeries

Annual incidence - 75,000 80,000 (USA)

Commonest surgery - Appendicectomy


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Surgeries in pregnancy

Pregnancy related

Cervical encirclage Fetal surgery Ovarian Cystectomy

Not related to pregnancy

Appendicectomy, Cholecystectomy Trauma Malignancies


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Altered maternal physiologyRespiratory system:

O2 consumptionrapid desaturation or hypoxemia

Alveolar ventilation chronic respiratory alkalosis &bicarbonate and base buffer

mucosal vascularity & weight gain difficult maskventilation or intubation

Cardiovascular system:

Supine hypotension syndrome uteroplacental perfusion

Distention of epidural venous plexus likelihood ofintravascular injection and enhanced spread of LA


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Altered maternal physiologyHematological changes

Blood volume with lesser increase in RBCs volumedilutionalanemia

Factor VII, VIII, X, XII, enhanced platelet turnover;clotting; and fibrinolysis Increased risk of thromboemboliccomplications

Benign leukocytosisdifficult to differentiate from infection

Gastrointestinal system changes LES tone, distortion of gastropyloric anatomy & gastric

pressure from gravid uterusrisk of regurgitation andaspiration


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Altered maternal physiology

Altered response to anaesthesia thiopental requirements

protein binding due to low albumin freefraction of drugs

sensitivity to peripheral neural blockade

L.A.dose requirement


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FETAL EFFECTSAnaesthetic agents andteratogenicity

Teratogenic effects of anaesthetic agents areprobably minimal to non-existent and have neverbeen conclusively documented


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INHALATION ANAESTHESIANitrous oxide

Animal studies

Weak teratogen in rodents

Interferes with function of methionine synthetase by oxidation of vitamin B12

decreased DNA synthesis

Decreased uterine blood flow : prevented by addition of halogenatedinhalational agents


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Nitrous oxide

Human studies

No proved teratogenicity

Significant exposure for prolonged duration results inaltered enzyme activity

No teratogenic effects in clinically administered dose.


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Sevoflurane and desflurane

are considered safe products.

No teratogenic effects have beenobserved in animal studies.

However, there are no adequate andwell-controlled studies in pregnantwomen


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halothane

The reports have been conflicting. Onestudy demonstrated an increased incidence

of aberrant skeletal development and fetaldeath when pregnant rats, in variousgestational periods, were exposed tohalothane for 12 hours.

Other investigators could not validate thisteratogenic effect when exposing rats,rabbits and mice to halothane


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enflurane or isoflu-rane

Pregnant mice exposed to showed anincreased incidence of cleft palate

None of these teratogenic findingshave been reported in humans despiteworldwide use of these products


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Induction Agentspropofol, etomidate, thiopental,

ketamineNeither is known to be a teratogen inclinically effective doses

lack of adequate and well-controlledstudies in pregnant women.


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Neuromuscular BlockingAgents

do not reach fetal circulation inclinically significant amounts

no teratogenic effect has beenreported after administration ofneuromuscular blocking agents to

pregnant women


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ANAESTHETIC MANAGEMENT

Postoperative Pain management

Painincreased endogenous catecholamines uterinevasoconstrictiondecreased UBFintrauterine hypoxia

Some well-documented case reports demonstrate the safeuse of opioids for acute and chronic pain

NSAIDS

1st and 2nd trimester - safe

3rd

trimester - risk of premature closure of DA,Pulm HTN, delayed labour

Paracetamol is safe


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BENZODIAZEPINES

Earlier retrospective studies:Association between maternal diazepam ingestion

during 1st trimester and infant with cleft lip and palate

Later prospective studies:

- No higher risk when used in 1st trimester

Long term maternal administration fetal BZDdependence & withdrawal

Peripartum administration

Fetal hypotonia, hypothermia, respiratory depression,feeding difficulties


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FETAL EFFECTSBEHAVIORAL TERATOLOGY

Behavioral abnormality in absence of any observablemorphological changes

CNS is specifically sensitive during period of majormyelination which extends from 4th IU month to 2ndpostnatal month

Animalsprenatal administration of systemic drugs

e.g., Barbiturates, meperidine, promethazine &halothane behavioral changes

Humanimplication remains unknown


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FETAL EFFECTS

There are not adequate data toextrapolate the animal finding tohumans

(Anesthetic & Life Support Drug advisory Committeeof US FDA)


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Fetal effects

To summarize, anaesthesia and surgery are associated withhigher incidence of abortion, IUGR and perinatal mortality.

These adverse outcomes can often be attributed to theprocedure, the site of the surgery (e.g., proximity to theuterus), and/ or the underlying maternal condition

No evidence that anaesthesia results in overall increase incongenital abnormality

No evidence of clear relation between outcome and type ofanaesthesia


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ANAESTHETIC MANAGEMENT ..

General anaesthesia

Maintain left uterine displacment

Preoxygenation

Rapid sequence induction (Thiopent. sod. & succinyl choline,cricoid pressure tracheal intubation using cuffed E.T. tube)

Maintenance : A moderate conc. of inhalational agent ( 2 MAC)with high conc. of oxygen (FiO2 = 0.5) is recommended.

The use of nitrous oxide should be limited during extremelylong operations in first trimester by giving high conc of oxygen


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Opioids and induction agents decreases FHR variabilityto greater extent than volatile agents

Positive pressure ventilation may reduce UBF

Avoid hyperventilation

Reversal agent to be given slowly (increased release of

Ach

increased uterine tone and preterm labour)

Extubation when fully awake after return ofprotective airway reflexes


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ANAESTHETIC MANAGEMENT..

Regional anaesthesia

Advantages:

Minimal fetal drug exposure

Avoidance of complications of general anaesthesia

If no sedative or narcotics are supplemented no change inFHR variations to confuse interpretation

Post operative analgesia


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Management of regional anaesthesia

Pre-op preparation and monitoring same as of Generalanaesthesia

Reduced LA requirement / LA Toxicity

Careful aspiration and test dose

Avoid hypotension i.e., adequate preloading, maintain leftuterine tilt, choice of vasopressor

Patients on magnesium are more prone to hypotension, oftenresistant to treatment with vasopressors


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ANAESTHETIC MANAGEMENT

Recommendations approved by AmericanSociety of Anaesthesiologists (ASA) andAmerican College of Obstetricians and

Gynecologists (ACOG) 2011

No currently usedanaesthetic agentshave been shown tohave anyteratogenic effectsin humans when usingstandard concentrations at any gestational age

Fetal heart rate monitoringmay assist in maternalpositioning and cardiorespiratory management, and mayinfluence a decision to deliver the fetus

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