Anesthesia for the Pregnant Patient Undergoing

NonOB-Surgery

Reference: Hawkins, JL. Anesthesia for the Pregnant Patient Undergoing

NonOB-Surgery. ASA Refresher Course. 2001.

Jeffrey Groom, MS, CRNA, ARNPFIU - Anesthesiology Nursing Program

NGR 6992 Principles of Anesthesiology Nursing II

NonOB SURGERY for OB Patients

Annually, 1 - 2.5% of pregnant patients require surgical procedures

Annually, approximately 75,000 anesthetics are administered

Whether or not your facility does OB Service, you will likely see OB patients

NonOB SURGERY for OB Patients

Most patients have a fear of anesthesia. Most OB patients have a profound fear

(concern) about anesthesia. Many will want to forego analgesia

and/or sedation…..which may in the end do more harm than good.

NonOB SURGERY PROCEDURES

MOST COMMON PROCEDURES: TRAUMA APPENDICITIS OVARIAN CYST CHOLECYSTECTOMY BREAST BIOPSY ABDOMINAL LAPAROSCOPIC PROCEDURES CERVICAL CERCLAGE

SURGICAL PROCEDURES

LESS COMMON PROCEDURESNEUROSURGICAL PROCEDURESCARDIAC SURGERYTRANSPLANTPHEOCHROMOCYTOMASUROLOGICAL PROCEDURES

(Extracorporeal shock-wave lithotripsy is absolutely contraindicated)

Fetal Surgery

Performed in a few major centers Major problem is postoperative preterm labor Tocolytics: Preoperative Indomethacin and

perioperative magnesium sulfate High dose inhalational anesthesia for

anesthetizing mother and fetus and provide uterine relaxation

RISK AND OUTCOME

RISK OF FETAL MORBIDITY RISES CONGENITAL MALFORMATIONS

DO NOT CORRELATE WITH ANESTHESIA EXPOSURE

INCREASE IN LOW BIRTH WEIGHT RISK OF EARLY PERINATAL DEATH INCREASE IN SPONTANEOUS AB

ANESTHESIA MANAGEMENT ISSUES IN PREGNANCY

1. ALTERATIONS IN MATERNAL PHYSIOLOGY

2. POSSIBLE TERATOGENIC EFFECTS

3. MAINTENANCE OF UTERINE PERFUSION AND EFFECTS OF ANESTHESIA ON FETUS

4. PREVENTION OF PREMATURE LABOR

Management Objective

Maintain: maternal oxygenation,cardiac output, oxygen delivery, and uterine blood flow

Blood Flow to Uterus

PHYSIOLOGIC CHANGES OF PREGNANCY

Late Gestation and Anesthesia Risks

Intubation difficulties with or without gastric acid aspiration

Unrecognized esophageal intubation High or complete spinal block during

regional anesthesia Unintended deep inhalational anesthesia

ANESTHETICS AND FETUS

RISK CHANGES WITH GESTATIONAL AGECONCEPTION TO DAY 13, ADVERSE

REACTIONS USUALLY RESULT IN DEATHORGANOGENESIS DAY 13 TO 90, MOST

VULNERABLEAFTER 13 WEEKS LESS DEVELOPMENTAL

RISKBY 3rd TRIMESTER, RISK IS GREATEST FOR

PRETERM LABOR

Changes in Risk Throughout Gestation

Early gestation - direct fetal effects mainly toxicity

Thalidomide Babies Late gestation - maternal effects that

indirectly produce fetal injury

Cerebral palsy induced by profound maternal hypoxia or hypotension near birth

Fetal Safety: Developmental Alterations

and Anesthesia Virtually all anesthetic agents given to

the mother are rapidly shared with the unborn child.

The notable exception to this statement is paralytic agents which cross the placenta with difficulty because they are quaternary ammonium salts.

Risk Classification System

The Food and Drug Administration (FDA) 1980

Drug Use in Pregnancy and Lactation Drug Facts and Comparisons Physicians Desk Reference

U.S. Food and Drug Administration Classification of

TeratogenicDrug Risk

Category Description of Risk

A Controlled studies show no risk.Well controlled human studies failed to demonstrate risk to fetus

B No evidence of risk in humans. Either animal studies show no fetal risk or animal studies show risk but human studies do not show risk

C Risk cannot be ruled out.

D Positive human evidence of fetal risk.

X Contraindicated in Pregnancy.

Adapted from Federal Register(1979)

TERATOGENICITY

TIMING OF ADMINISTRATION INDIVIDUAL SENSITIVITY TO THE AGENT THE THRESHOLD AMOUNT OF EXPOSURE NATURALLY OCCURING INCIDENCE OF

CONGENITAL ANOMALIES

DOCUMENTED TERATOGENS ACE INHIBITORS ALCOHOL ANDROGENS ANTITHYROID CHEMO-DRUGS COCAINE COUMADIN DIETHYLSTIBESTEROL

LEAD LITHIUM MERCURY PHENYTOIN STREPTOMYCIN THALIDOMIDE TRIMETHADIONE VALPROIC ACID

MEDICAL & SOCIAL FACTORS

DIABETIC MOTHERS DRUG ABUSE - MOTHER & FATHER GENETIC PREDISPOSITION HYPOXIA EXTREMES IN TEMPERATURE ENVIRONMENTAL HAZARDS

FDA

FDA ratings

DRUG CATEGORY

Induction agents

Thiopental C

Methohexital B

Ketamine C

Etomidate C

Propofol B

Categories

Inhaled Agents

Halothane C

Enflurane B

Isoflurane C

Desflurane B

Sevoflurane B

Categories

Local Anesthetics

2-Chloroprocaine C

Tetracaine C

Bupivacaine C

Lidocaine B

Ropivacaine B

NITROUS OXIDE

CONTROVERSIAL SMALL ANIMAL STUDIES AND DNA SYNTHESIS N20 - ADRENERGIC TONE -VASOCONSTRICTION TERATOGENICITY HAS NOT BEEN

DEMONSTRATED IN HUMANS CATEGORY X ?

BENZODIAZEPINES

CLEFT PALATE AND EXPOSURE TO DIAZEPAM IN FIRST TRIMESTER

LACK OF DATA STILL CLASSIFIED AS A CATEGORY D

AGENT USE OR NOT PDR

FETAL OUTCOMEAFTER SURGERY

NO ANESTHETIC AGENTS EXCEPT COCAINE IS TERATOGENIC

HOWEVERAVOID HYPOXIA, HYPERCARBIA, AND

HYPOTENSION, ALL CAPABLE OF INDUCING

MALFORMATIONS AND FETAL DEATH

PreAnesthesia Assessment and Risks vs. Benefits

PRE-ANESTHESIA ASSESSMENT

WOMEN OF REPRODUCTIVE AGE CHECK FOR POSSIBLE PREGNANCY

PATIENT INFORMATION AND RISK COUNSELING POSTPONE ELECTIVE SURGERY UNTIL AFTER

DELIVERY POSTPONE NONELECTIVE SURGERY UNTIL

SECOND TRIMESTER NO ANESTHETIC TECHNIQUE CORRELATES

WITH A BETTER OUTCOME EDUCATE ON SIGNS OF PRETERM LABOR

TYPE OF ANESTHESIA IS DICTATED BY:PHYSICAL & MENTAL CONDITION OF PATIENTEXTENT OF PLANNED PROCEDUREPERCEPTION THAT MAC > Regional > GETA IS

SAFEST ORDER OF ANESTHESIA METHODS, NOT VALIDATED BY THE DATA

Type of Anesthesia

PREOPERATIVE TREATMENT

HISTORY AND PHYSICAL EXAM AIRWAY ASSESSMENT PATIENT RAPPORT ALLEVIATE ANXIETY ADVISE AS TO RISKS OB CONSULTATION PRE-OP MEDICATIONS

GENERAL GUIDELINES

ASPIRATION PRECAUTIONS POSITIONING MONITORING

Management Objective

Maintain: maternal oxygenation,cardiac output, oxygen delivery, and uterine blood flow

Risk Factors for Aspiration in Pregnancy Compromised LES function Higher intragastric pressure Anatomic displacement of stomach Decreased gastric emptying in labor Potential for no NPO period Potential for difficult intubation

Factors Known to Worsen Aspiration Syndrome

Solid material aspiration Increased acidity of contents Higher aspirated volume

Regardless of NPO status all pregnant patients are at risk for aspiration from 8 weeks gestation to 6-8 weeks postpartum!

Agents for aspiration prophylaxis

Ranitidine (Zantac) 50mg IV Cimetidine 300 mg IV Metoclopromide (Reglan) 10

mgIV Oral sodium citrate( Bicitra)30cc

po

MATERNAL POSITIONING

BEGINNING WITH SECOND TRIMESTER, AVOID SUPINE POSITION

USE LEFT UTERINE DISPLACEMENT

FETAL MONITORING

BECOMES PRACTICAL AFTER 16-24 WEEKS GESTATION

EQUIPMENT AND PERSONNEL MUST BE AVAILABLE

TRANSDUCER MUST NOT ENCROACH ON THE SURGICAL FIELD

THERAPEUTIC INTERVENTIONS?

FETAL MONITORNG

Loss of beat-to-beat variability is normal after anesthesia

Decelerations may indicate need for: Increased oxygenation, increased BP Decreased surgical retraction Initiation of tocolytics

HOWEVER, MONITORING NEEDS TO BE ACCURATE AND PROPERLY INTERPRETED

INDUCTION AND MAINTENANCE• AVOID HYPOXIA• AVOID HYPOTENSION• AVOID HYPERTENSION• AVOID HYPER/HYPOCARBIA• AVOID HYPOGLYCEMIA• AVOID HYPO/HYPERTHERMIA

REGIONAL

Decrease dose by 1/3 Prehydrate Treat hypotension with fluid &

ephedrine If not used operatively, consider

regional for post-op pain management

PostOperative

Monitor VS and FHT Treat preterm labor Appropriate pain management Increased risk for thromboembolism

Trauma Leading cause of maternal death Fetal death secondary to maternal death or

abruptio placenta Fetal Assessment – STAT Ultrasound Maternal Evaluation – Shield fetus STAT Post-mortum C-Section Stabilize/Optimize mother – VD or CS at 9mo

better than emergent CS at time of injury Emergent C-Section:

Stable MOM – FETAL distress Traumatic uterine rupture – Unstable MOM and FETUS Gravid uterus interfering with MOM E-lap Unsalvageable MOM with viable FETUS

Appendectomy and Adnexal MassesMost Common Surgery

Parturients undergoing appendectomy have an 18% incidence of postoperative pulmonary edema or ARDS

Risk Factors for development of pulmonary edema are:

Gestational age > 20 weeks Preoperative respiratory rate over 24 /min Preoperative temperature > 100.4°F A fluid load (I>O) > 4 liters in the first 48 hours Concomitant tocolytic usage

Conservative FLUIDS, consider CVP line

Laparotomy Versus Laparoscopic Surgery

Laparoscopy – most common 1st trimester procedure

Reduced pain and limited fetal exposure to postoperative opioids

More economical Better surgical view with limited

manipulation of uterus More rapid return to mobility, reducing risk

of thrombophlebitis

CO2 Pneumoperitoneum

Continuous FHR monitoring ? Limit abdominal insufflation pressure

to 15 to 20 mm Hg Increase minute ventilation If fetal compromise develops-check

ABG Convert to Open procedure

Cervical Cerclage

Cervical cerclage is the surgical intervention used to prevent second - trimester fetal loss from cervical incompetence.

An incompetent cervix is the result of weakness of cervical os caused by trauma, congenital or multiple pregnancies

Usually done between 12 and 26 weeks gestation

Contraindications to cervical cerclage Bleeding Active labor Ruptured membranes Cervical dilation > 4 cm Intrauterine infection Fetal abnormalities Abruptio Placenta

SUMMARY <16-20 WEEKS GESTATION

POSTPONE UNTIL 2nd TRIMESTER, PRN PRE-OP EVAL. BY OBSTETRICIAN PRE-OP COUNSULING NONPARTICULATE ANTACID OXYGENATION,NORMOCARBIA, NORMOTENSION

& NORMOGLYCEMIA REGIONAL if possible FOR GETA – WEIGH BENEFIT v RISK of N2O DOCUMENT FHT’s BEFORE, DURING, AFTER

SUMMARY > 16-20 WEEKS GESTATION

COUNSUL PREOPERATIVELY TOCOLYTIC AGENTS? ASPIRATION PROPHYLAXIS USE LEFT UTERINE DISPLACEMENT OXYGENATION, NORMCARBIA,

NORMOTENSION, & NORMOGLYCEMIA USE FHR MONITORING & MONITOR FOR

UTERINE CONTRACTIONS

QUESTIONS ?