3 Objectives Definition of ambulatory anesthesia Preoperative Evaluation History takingPhysical examinationFasting & medicationsLaboratory screeningPremedicationMonitorizationAnesthesia choicesPostoperative Carefor obstetric procedures done on ambulatory basisAmbulatory surgery-anesthesia facilities can be hospital based, freestanding or office based.Primary objective of preop.assessment for the ADULT ambulatory anesthesia is to identfy patients who have concurrent medical problems requiring further diagnostic evaluation or active treatment before surgery. Specific anesthetic concerns (difficult airway orMH susceptibility) or preexisitng medical conditions that may be associated with adverse events include hypertension, obesity, asthma, smoking, and gastroesophageal reflux diseases.
4 Definition Ambulatory (outpatient) surgery Basic advantages Economic savingsEarlier ambulationLessened risk of nosocomial infectionsAnesthesia for ambulatory surgeryPatients return home within 24 hours of an operative procedureAmbulatory surgery-anesthesia facilities can be hospital based, freestanding or office based.Primary objective of preop.assessment for the ADULT ambulatory anesthesia is to identfy patients who have concurrent medical problems requiring further diagnostic evaluation or active treatment before surgery. Specific anesthetic concerns (difficult airway orMH susceptibility) or preexisitng medical conditions that may be associated with adverse events include hypertension, obesity, asthma, smoking, and gastroesophageal reflux diseases.
5 Procedures done on ambulatory basis Evacuation of incomplete miscarriageSurgical treatment of tubal ectopic pregnancyCervical cerclageExternal cephalic versionHysterosalpingography (HSG) - HysteroscopyAssisted reproductive technologies - proceduresTransvaginal ultrasound guided oocyte retrieval (TUGOR)Selection of surgical procedures commonly undertaken as day-casesGynae: D&C, laparoscopy, VTOP, colposcopy
6 Preoperative Evaluation History taking Questionnaires for screening & detecting common medical problemsMaternal death & anesthetic historyRelevant obstetric historyMedical history is clearly the most valuable of the 3 primary components of preop.assessment (1. history, p. Exam, laboratory testing).MH susceptible patients can be successfully managed with non-trigering anesthetics under local anesthesia.After uneventful surgery-anesthesia, MH susceptible patients should be observed for at least 4 hours postoperatively and their families should be advised about the signs of MH in addition to the usual postoperative instructions.
8 Preoperative Evaluation Fasting & Chronic medications Clear fluidsModest amount is allowed up to 2 h prior to induction of anesthesiaSolidsshould be avoided 6-8 h depending on the type of ingestion (e.g.fat)Patients should bring their own medicationsAntihypertensives should be takenOral hypoglycaemics should be omittedNil by mouth:NPO. Fasting policies have allowed patients to continue taking chronic medications (up to 30 min before surgery) and avoid uncomfortable symptoms of dehydration, hypoglycemia, and cafeine withdrawal.White P. Ambulatory anesthesia advances into the new ilennium. Anesth Analg 2000Hawkins. ASA Practice Guidelines for Obstetric Anesthesia IJOA 2007
9 Preoperative Evaluation Laboratory screening Platelet countMaternal historyPhysical examinationClinical signsBlood type & cross-matchAnticipated hemorrhageInstitutional policiesAgeMen ♂Women ♀<40NonePregnancy test40-49ECGHtc50-64Hb/ Htc, ECG65-74Hb/ HtcECG, BUNGlucose>75Chest radiographLaboratory test recommendations for outpatients under general anesthesia are shown in the table. Patients with chronic diseases like hypertension and diabetes require additional laboratory studies (electrolytes or glucose). Unexplianed Hb < 10 g/dl should undergo further evaluation before elective surgery.Routine platelet count and blood cross-match are not necessary in the healthy and uncomplicated parturients.Hemorrhagic complications are anticipated in placenta accreta in a patient with plasenta previa and previous uterine surgery.White & Freire. Ambulatory (outpatient) Anesthesia. Anesthesia 2005ASA Task Force on Obstetric Anesthesia Practice Guidelines Anesthesiology 2007
10 Premedication Benzodiazepines if indicated Alpha-2 agonists Small dose of midazolam IV (1-3 mg)Alpha-2 agonistsClonidine ( PO)Dexmedetomidine (50-70 µg IM or 50 µg IV)Aspiration prophylaxis (for diabetics & morbid obeses)H2-receptor antagonists (ranitidine)Nonparticulate antacids (sodium citrate)Gastrokinetic agents (metoclopramide)White P. Ambulatory Anesthesia. Anesthesia 2005Hawkins JL. ASA Practice Guidelines for Obstetric Anesthesia. IJOA 2007
11 Monitorization Heart rate (maternal & fetal) and ECG Blood pressure (noninvasive)Pulse oximetry (SpO2)Capnometry (ETCO2)BISUse of electroencephalographic bispectral index monitoring can improve maintenance of anesthesia, thereby facilitate the early recovery process. FHR should be monitored by a qualified individual before and after adminstration of neuraxial labor analgesia but continuous monitoring may not be necessary in every clinical setting and may not be possible during initiation of neuraxila anesthesia.White P. Ambulatory anesthesia advances into the new ilennium. Anesth Analg 2000ASA Task Force on Obstetric Anesthesia Prcatice GuidelinesAnesthesiology 2007
12 Anesthesia Techniques General AnesthesiaRegional anesthesiaMonitored Anesthesia Care (MAC)Local AnesthesiaBorkowski. Cleveland Clin J Med 2006
13 General Anesthesia Induction agents Propofol ( mg/kg) is used widely(easy +quick recovery, clear head, lacks PONV)Sevoflurane (8% in 50% N2O-O2)non-irritant to airway, rapid induction, minimal side-effects, but more PONVThiopentone (3-6 mg/kg)Midazolam ( mg/kg)Etomidate ( mg/kg)Ketamine ( mg/kg)Endtidal vapor concentration>0.75 MAC (+50% N2O)Borkowski. Cleveland Clin J Med 2006White. Anesth Analg 2000Russell R. Summer Update on Obstetric Anesthesia, 2006Levy D. Three day course on obstetric anesthesia, 2007
14 General Anesthesia Maintenance TIVA (propofol & remifentanil or alfentanil)-TCI(BIS < 60)Endtidal vapor concentration>0.75 MAC (+50% N2O)Borkowski. Cleveland Clin J Med 2006White. Anesth Analg 2000Russell R. Summer Update on Obstetric Anesthesia, 2006Levy D. Three day course on obstetric anesthesia, 2007
16 General Anesthesia Maintenance IsofluraneSevofluraneDesflurane? N2O
17 General AnesthesiaMuscle relaxants (short and intermediate acting drugs)MivacuriumRocuroniumCisatracuriumAirwayFace maskLMAEndotracheal intubationEndtidal vapor concentration>0.75 MAC (+50% N2O)Borkowski. Cleveland Clin J Med 2006White. Anesth Analg 2000Russell R. Summer Update on Obstetric Anesthesia, 2006Levy D. Three day course on obstetric anesthesia, 2007
19 Spinal anesthesia Advantages Disadvantages Simple-quick procedure Short turnover timePatients are alertLess nausea-vomitingDisadvantagesIncidence of headache and radiating back painSlow return of motor powerDifficulty in micturition might delay dischargeRare but significant advers events (neurologic injury, infection)Chakravorty et al. Spinal anesthesia in the ambulatory setting. Ind J Anaesth 2003Mordecai & Brull Curr Opin Anaesthesiol 2005, Korhonen. Curr Opin Anaesthesiol 2006
20 Spinal anesthesia Prevention against disadvantages 27 G Whitacre spinal needle is associated with lower incidence of PDPHOlder (chloroprocaine) & newer (ropivacaine & levobupivacaine) local anesthetics in conjuction with adjuvant intrathecal medications (opioids, vasopressors) help fast resolution of motor function and ability to micturateMordecai & Brull Curr Opin Anaesthesiol 2005Korhonen. Curr Opin Anaesthesiol 2006
21 Neuraxial anesthetics Ideal neuraxial anestheticAdaequate analgesia and durationShort recoveryMinimal side effects7.5 mg of spinal hyperbaric bupivacaine is with low incidence of TNSEpidural with 2-chloroprocaine is preferable to spinal anesthesia
23 Maintenance (µg/kg/min) Drugs used for MACDrugLoading dose (µg/kg)Maintenance (µg/kg/min)Alfentanil10-250.25-1Fentanil1-3SufentanilRemifentanil-Ketamine10-20Propofol10-50Midazolam25-100
24 Postoperative Care Pain Multimodal approachNSAID and/or nonopioid analgesics (local anesthetics, acetaminophen, proparacetamol)COX2 inhibitors (celecoxib)LA wound infiltrationat the time of surgerypatient controlled elastomeric pumpNeuraxial opioidsNSAIDs are effective in relieving the visceral cramping pain. Diclophenac appears particularly efficacious. NSAIDs reduce need for opioid analgesics up to 30% and opioid related effects (nausea, pruritis, respiratory depression, sedation) and may augment analgesic effect of spinal morphine. NSAIDs are generally safe in breastfeeding parturient due to the large molecular size and high protein binding properties of NSAIDs, there is minimal transfer to breastfeeding neonate compared to opioids. However, potential maternal side effects (gastric bleeding, renal dysfunction, delayed wound healing and bleeding due to impaired platelet function) have raised questions about their use andeffects on breatfeeding neonate especially NSAIDs with long half-lives.When neuraxial block has not been used wound infiltration or ilioinguinal block imprves quality of initial postoperative pain relief.White P. Anesth Analg 2000Carvalho B. Summer Update on Obstetric Anesthesia, 2006
25 Postoperative Care PONV Prophylactic antiemeticsMultimodal treatment regimenButyrophenonesPhenotiazinesGastrokinetic drugsAnticholinergicsAntihistaminesSerotonin antagonists (4-8 mg IV)NK-1 antagonistsDexametazone (4-8 mg IV)Acupuncture (P6 and others)NK:NeurokininWhite P. Anesth Analg 2000White & Freire. Anesthesia 2005
26 Discharge Criteria Aldrete ActivityRespirationCirculationConscious levelColor of the skinPostanesthesia Discharge Scoring System (PDSS)Vital signsActivity levelNausea &vomitingPainSurgical bleedingChakravorty et al. Spinal anesthesia in the ambulatory setting.Ind J Anaesth 2003
27 Surgical treatment of miscarriage (vacuum aspiration or D&C) Anesthetic optionsTarget-controlled intravenous sedation-analgesia with propofol & remifentanilParacervical block (PCB)Sedation + PCB (MAC)Short acting iv induction or inhalation agent (sevoflurane) with short acting opioid/N2O mask ventilation or LMATermination of pregnancyNanda K et al. Cochrane Data Base Syst Rev 2006Fassoulaki et al. No change in plasma endorphine and melatonine levels after sevoflurane anesthesia. JCA 2007
28 Hysterosalpingography (HSG) Any analgesics (oral or topical) vs placebo or no treatmentTopical analgesics vs placebo or no treatmentOpioid vs non-opioid analgesicsTopical analgesics vs oral analgesicsIntaruterine local anesthetic vs PCBHSG is a method of testing tubal patency.Various pharmacological strategies are available that may reduce the pain during the procedure.Ahmad G et al. Cochrane Data Base Syst Rev 2007
29 Hysteroscopy Local MAC General Regional Spinal anesthesia to T7 level was achieved using 3 mL of 2% isobaric lidocaine (60 mg) with 100 µ epinephrine*TNS was associated with single shot spinal anesthesiaHSG is a method of testing tubal patency.Various pharmacological strategies are available that may reduce the pain during the procedure.Lotfallah et al. J Reprod Med. 2005Farid et al. JCA 2001
30 Tubal ectopic pregnancy Treatment options requiring anesthesia are salpingectomy or salpingostomy either laparoscopically or open surgeryGeneral anesthesiaInductionwith short acting iv agent (usually propofol)Maintenancewith TIVA or sevo/desflurane in N2O/opioidHajenius PJ et al. Cochrane Data Base Syst Rev 2007
31 Cervical CerclagePrevents miscarriage or premature delivery due to cervical incompetence in 85-90% of cases and requires anesthesiaRegionalusually spinal anesthesiaepiduralGeneral anesthesiaProcedure used to temporarily stitch the cervix closed in pregnant women with a history of miscarriage or premature.
32 Cervical Cerclage Neuraxial anesthesia (spinal or epidural) Use of low-dose epidural0.125% bupivacaine with epinephrine & fentanylSpinal anesthesialidocaine 30 mg or bupivacaine 5.25 mg both with fentanyl 20 µg have been used successfully for cervical cerclageProcedure used to temporarily stitch the cervix closed in pregnant women with a history of miscarriage or premature.Tsen. What’s new and novel in obstetric anesthesia?IJOA 2005Schumann & Rafique. Low dose epidural anesthesia for cervical cerclage. CJA 2003; 50:424
33 External Cephalic Version Spinal analgesia with 7.5 mg bupivacaine (n=36) vs with no analgesia (n=34)Success rateSpinal (66.7%) vs no analgesia (32.4%) (p=0.0004)Spinal analgesia significantly increases success rate of external cephalic version among parturients at term which allows possible normal vaginal deliveryProcedure used to temporarily stitch the cervix closed in pregnant women with a history of miscarriage or premature.Weiniger et al. External cephalic version for breech presentation with or without spinal analgesia in nulliparouswomen at term: a randomized controlled trial. Obstet Gynecol. 2007;110:
34 TUGOR General Regional blocks Conscious sedation (MAC) Inhalational anesthesiaTIVARegional blocksSpinalEpiduralPCBConscious sedation (MAC)PCB + IV remifentanilTsen. Int Anaesthesiol Clin 2007Gunaydin et al.J Opioid Manag 2007
37 CONCLUSIONS Ambulatory surgery aims the best patient care possible at the reasonable cost, ambulatory anesthesiamust meet these requirementsIssues that prolong stay in PACU primarilyPain & PONV after general anesthesia or MACUnresolved blocks & urinary retention after neuraxial blocksshould be managed by choosing appropriate pharmacologic agents (mainly short acting agents with less side effects)