Preoperative Anesthesia Evaluation
Pregnant patients with the following conditions should ideally undergo evaluation by an anesthesiologist by 32 weeks gestation, or earlier if premature delivery is anticipated:
- Thrombocytopenia- (platelet count < 100,000 x 106/L) with known diagnosis
- Thrombocytopenia- (platelet count < 100,000 x 106/L) with unknown diagnosis should be referred to hematology expert prior to 32 weeks, and then to anesthesiologist
- Thromboprophylaxis/Anticoagulation therapy
- Known factor deficiency or Platelet Disorder
- Sickle Cell Disease
- Valvular disease with moderate-severe degree of functional impairment
- History of chest pain without negative cardiac work-up
- Arrythmias (specifically SVT, atrial fibrillation, VT)
- Cardiomyopathy or IHSS
- Complex congenital cardiac defects (excluding simple ASD or VSD repair as an infant)
- Pulmonary Hypertension (moderate-severe)
- History of Coronary Artery Disease or Myocardial Infarction
- Spinal Anatomic Aberrations: such as: prior surgery (excluding simple disc-related); moderate to severe scoliosis (corrected or uncorrected); spinal cord injury; spina bifida (other than asymptomatic, incidental finding on imaging; hardware (eg, spina cord stimulators, VL shunts); severe low back pain
- Neuromuscular disease: (eg multiple sclerosis with significant functional compromise), myasthenia gravis, Guillian-Barre
- Intracranial lesion: e.g. tumor, vascular lesion, hemorrhage (excluding incidental finding with no anatomic consequence, or pituitary microadenoma)
- Arnold Chiari malformation
- Patients with Previous Cerebral Ischemia or Stroke – especially with residual deficits
- Asthma/Reactive Airway Disease- symptomatic despite medical therapy
- Airway Compromise (eg., tracheal stenosis, history of neck radiation or jaw surgery, restricted mouth opening, severe tooth decay)
- Other Pulmonary disease (eg, cystic fibrosis, prior lung surgery, restrictive lung disease)
- Patients with solid organ dysfunction or transplant – Liver Cirrhosis, End-Stage Renal Disease
- Rheumatology – patients with severe systemic autoimmune diseases (e.g. Systemic Lupus Erythematous)
- Morbid Obesity (each institution may determine their threshold for preoperative evaluation)
- Local Anesthetic or Opioid Allergy
- Opioid Use Disorder (if possible, even if on stable opioid replacement therapy)
- History of anesthetic issues or complications in patient or first-degree relative family members (e.g. Malignant Hyperthermia; history of difficult airway)
- Refusal of Blood products (e.g. Jehovah’s Witness)
- Patient with suspected abnormal placentation – (accreta, increta, percreta)
- Request for non-standard accommodations during admission; general educational questions or concerns about obstetric anesthesia care.
Neuraxial Anesthesia – Coagulopathy
Thrombocytopenia is commonly encountered in the obstetric population, with ~2% of parturients demonstrating platelet counts less than 100,000/mm3.1,2 Given the theoretical risk of epidural hematoma, thrombocytopenia is considered a relative contraindication to neuraxial anesthesia. Several studies have attempted to delineate the platelet count at which it is “safe” to attempt a neuraxial technique. Recent evidence suggests the risk of epidural hematoma is extremely low in parturients with platelet counts > 70,000/mm3.1-3 The risk of epidural hematoma with platelet counts < 70,000/mm3 remains poorly defined.
The etiology of thrombocytopenia and considerations for platelet function should be considered when making a decision for neuraxial anesthesia. The use of platelet function analysis (PFA), thromboelastography, or thromboelastometry to guide a decision for neuraxial analgesia and anesthesia placement is controversial.
–Emily Baird, MD
Oregon Health Sciences University
- Lee LO, Bateman BT, Kheterpal S, et al. Risk of epidural hematoma after neuraxial technique in thrombocytopenic parturients. Anesthesiology 2017; 126: 1053-63.
- Levy N, Goren O, Cattan A, et al. Neuraxial block for delivery among women with low platelet counts: a retrospective analysis. Int J Obstet Anesth 2018; 35: 4-9.
- Goodier CG, Lu JT, Hebbar L, Segal BS, Goetz L. Neuraxial anesthesia in parturients with thrombocytopenia: a multisite retrospective cohort study. Anesth Analg 2015; 121: 988-91.
Gestational thrombocytopenia is a benign condition diagnosed by exclusion in parturients with platelet counts lower than 150K, and usually does not fall below 80K. Platelet function is not affected on these patients. Multiples retrospective studies have found minimal risk for epidural hematoma after neuraxial procedures on patients with platelet counts between 70 and 100K (Incidence < 0.2%). Below that number, a specific platelet count predictive of neuraxial complications has yet to be determined. If other conditions have been ruled out and the platelet count is above 70K, neuraxial placement is probably safe. More data is needed for lower counts.
–Maria Cristina Gutierrez, MD
University of California Davis Medical Center
- Ciobanu AM, Colibaba S, Cimpoca B, Peltecu G, Panaitescu AM. Thrombocytopenia in Pregnancy. Maedica (Buchar). 2016 Mar;11(1):55-60.
- Levy N, Goren O, Cattan A, Weiniger CF, Matot I. Neuraxial block for delivery among women with low platelet counts: a retrospective analysis. Int J Obstet Anesth. 2018 Aug;35:4-9.
- L. Apfelbaum, J.L. Hawkins, M. Agarkar, et al. Practice Guidelines for Obstetric Anesthesia: an updated report by the American Society of Anesthesiologists Task Force on Obstetric Anesthesia and the Society for Obstetric Anesthesia and Perinatology. Anesthesiology, 124 (2016), pp. 270-300
Neuraxial Anesthesia – Techniques
Loss of resistance to air versus saline for epidural placement remains controversial and incites polarizing opinions despite a lack of randomized clinical trials to support the superiority of one technique over another. Saline supporters report a lower risk for accidental dural puncture, difficulty threading the epidural catheter, nerve root compression, incomplete analgesia, venous air embolism, or pneumocephalus and headache. Ultimately, a retrospective study evaluating the effectiveness of loss of resistance to air or saline for identification of the epidural space found that clinicians should practice their preferred technique, whether air or saline, as this practice will result in fewer attempts, paresthesias, and accidental dural punctures.
Jennifer Hofer, MD
University of Chicago
- Van de Velde, M. Identification of the epidural space: Stop using the loss of resistance to air technique!. Acta Anaesth Belg 2006; 57:51-4.
- Segal S, Arendt KW. A retrospective effectiveness study of loss of resistance to air or saline for identification of the epidural space. Anesth Analg 2010; 110:558-63.
Labor and Delivery
Unfortunately, there are no definitive data to suggest optimal fasting times during labor. However, the American Society of Anesthesiologists (ASA) Task Force on Obstetric Anesthesia, in concert with SOAP, has issued recommendations regarding nil per os (NPO) restrictions for parturients. These guidelines recommend allowing “moderate” amounts of clear liquids for women in labor; solid foods should be avoided.1 It may be prudent to consider further dietary restrictions during labor for women with risk factors for aspiration or for operative delivery.1 Patients undergoing elective cesarean delivery should be subject to standard NPO guidelines, avoiding clear liquids 2 hours prior to induction of anesthesia and solid foods 6-8 hours prior.2
Sharon Reale, MD
Brigham and Women’s Hospital, Boston, MA
- Practice Guidelines for Obstetric Anesthesia: An Updated Report by the American Society of Anesthesiologists Task Force on Obstetric Anesthesia and the Society for Obstetric Anesthesia and Perinatology. Anesthesiology 2016;124:270-300.
- Practice Guidelines for Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration: Application to Healthy Patients Undergoing Elective Procedures: An Updated Report by the American Society of Anesthesiologists Task Force on Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration. Anesthesiology 2017;126:376-93.
While oxytocin is the most frequently used uterotonic agent in cesarean deliveries, large doses can lead to cardiovascular compromise or even collapse. Several safe dosing strategies for postpartum oxytocin infusion or administration exist. Tsen and colleagues have posited a “rule of threes” algorithm for administration of oxytocin that involves a 3 units intravenous loading dose, followed by additional 3 units rescue doses at 3 minute intervals for 3 total doses as needed; these initial loading doses should be followed by a maintenance infusion of oxytocin.1 This algorithm was validated in a randomized control trialthat showed adequate uterine tone with lower doses of oxytocin in the rule of threes group vs. the standard group that received “wide open” oxytocin infusions; there were no differences in uterine tone or blood loss.2
Sharon Reale, MD
Brigham and Women’s Hospital, Boston, MA
- Tsen LC, Balki M. Oxytocin protocols during cesarean delivery: time to acknowledge the risk/benefit ratio? Int J Obstet Anesth 2010;19:243-5.
- Kovacheva VP, Soens MA, Tsen LC. A Randomized, Double-blinded Trial of a “Rule of Threes” Algorithm versus Continuous Infusion of Oxytocin during Elective Cesarean Delivery. Anesthesiology 2015;123:92-100.
For More Information:
- Rule of threes algorithm: http://anesthesiology.pubs.asahq.org/data/Journals/JASA/934156/21FF02.png
Current recommendations for left uterine displacement (LUD) in cesarean delivery include maintenance of the LUD until delivery of the fetus [1,2]. This basic principle is based on previous findings that the supine position increases aortocaval compression, maternal hypotension and fetal compromise . In the supine position, the inferior vena cava is completely obstructed; however, most women experience limited hemodynamic change and are asymptomatic . Clinically significant hemodynamic effects, also called “supine hypotensive syndrome”, is estimated to occur in 8 to 10% of women at term gestation .
A few modern studies have countered the standard recommendation for LUD in elective cesarean delivery. Lee, et al.  found that maternal supine position during elective cesarean delivery with spinal anesthesia in healthy term women does not impair neonatal acid-base status compared to a 15-degree left tilt. During the study, maternal systolic blood pressure was maintained with a co-load of fluid and phenylephrine infusion. However, these findings were limited to healthy pregnant women and should not be generalized to emergency situations or non-reassuring fetal status. The care team should also be aware that phenylephrine requirements were greater in those who were supine versus those with a 15-degree tilt.
Michael H Wilhelm, DNP, CRNA, APRN
University of Connecticut/John Dempsey Hospital
- NICE, NIfHaCE: Clinical guidelines and updates: Caesarean section. Available at: https://www.nice.org.uk/guidance/cg132/chapter/1-guidance. Accessed November 16, 2018.
- Practice guidelines for obstetric anesthesia: An updated report by the American Society of Anesthesiologists Task Force on Obstetric Anesthesia and the Society for Obstetric Anesthesia and Perinatology. Anesthesiology 2016; 124:270–300.
- Higuchi, H, Takagi, S, Zhang, K, Furui, I, Ozaki, M : Effect of lateral tilt angle on the volume of the abdominal aorta and inferior vena cava in pregnant and nonpregnant women determined by magnetic resonance imaging. Anesthesiology 2015; 122:286–93.
- Howard, BK, Goodson, JH, Mengert, WF : Supine hypotensive syndrome in late pregnancy. Obstet Gynecol 1953; 1:371–7.
- Kinsella, SM, Lohmann, G : Supine hypotensive syndrome. Obstet Gynecol 1994; 83:774–88.
- Lee AJ, et al. : Left Lateral Table Tilt for Elective Cesarean Delivery under Spinal Anesthesia Has No Effect on Neonatal Acid-Base Status: A Randomized Controlled Trial. Anesthesiology 2017; 127(2):241-249.
For scheduled, non-urgent cesarean delivery without profound vaginal bleeding and with a reassuring fetal status, a single shot spinal or other neuraxial anesthetic can be safely performed. If the patient had a bleeding episode recently, the patient should be adequately volume resuscitated prior to performing the neuraxial; clinical judgment should be used to determine if preoperative coagulation testing is needed to determine the safety of neuraxial anesthesia. If there is suspicion of a placenta accreta spectrum in a patient with previa (e.g. placenta previa in current pregnancy with known prior low-transverse cesarean scar), then excessive bleeding should be anticipated, and appropriate preparations made. In such cases, an epidural or a combined spinal-epidural may be performed to allow extension of surgical time, with selective conversion to general anesthetic if massive hemorrhage is encountered. Placenta previa in the absence of other risk factors is not a contraindication for neuraxial anesthesia for cesarean delivery.
Sonal Zambare, MD;
Baylor College of Medicine, Houston, TX
- Markley JC, Farber MK, Perlman NC, Carusi DA; Neuraxial anesthesia during Cesarean delivery for placenta previa with suspected morbidly adherent placenta: A Retrospective Analysis; Anesthesia and analgesia; VOL.:127, ISSUE: 4; 930-938
- Berrin Günaydın, Mertihan Kurdoğlu, İsmail Güler, et al; Management of Neuraxial Anaesthesia for Emergent Caesarean Section for Placenta Previa; Turkish journal of anaesthesiology and reanimation; 2016; 44: 40-3
The two major risks of placing a spinal after a failed epidural analgesia conversion to anesthesia, are 1) spinal failure due to presence of fluid in the epidural space that can be mistaken for CSF, and 2) the development of a high neuraxial block (HNB). 27% of HNB occur after a spinal technique following a failed epidural. Presence of fluid in the epidural space decreases the intrathecal (IT) volume therefore causing cephalad distribution of the local anesthetic. To minimize that risk, one approach can be to decrease the IT dose of local anesthetic and/or associate it with a catheter-based technique (epidural or CSE), to extend the duration of anesthesia if needed.
–Maria Cristina Gutierrez, MD
University of California Davis Medical Center
- D’Angelo R, Smiley RM, Riley ET, Segal S. Serious Complications Related to Obstetric Anesthesia: The Serious Complication Repository Project of the Society for Obstetric Anesthesia and Perinatology. Anesthesiology 2014;120(6):1505-1512.
- Ginosar Y, Mirikatani E, Drover DR, Cohen SE, Riley ET. ED50and ED95of Intrathecal Hyperbaric Bupivacaine Coadministered with Opioids for Cesarean Delivery. Anesthesiology 2004;100(3):676-682.
- Higuchi H, Takagi S, Onuki E, Fujita N, Ozaki M. Distribution of Epidural Saline Upon Injection and the Epidural Volume Effect in Pregnant Women. Anesthesiology 2011;114(5):1155-1161.
External Cephalic Version
External cephalic version (ECV) is encouraged by ACOG as a method to reposition the breech fetus to a vertex presentation before the onset of labor with the hope of avoiding a Cesarean delivery and facilitate a vaginal one. There is evidence1 that neuraxial (spinal, combined spinal-epidural (CSE), and epidural) analgesia and/or anesthesia improves the success rate of the ECV. While there are numerous studies demonstrating this effect, optimal dosing has not been fully established. A recent randomized study by Chalifoux2 et al. did not show any increased success with intrathecal bupivacaine doses greater than 2.5mg as part of a CSE with intrathecal fentanyl 15mcg. Carvalho and Bateman3 suggest, however, that the optimal dose for a given patient may depend on the clinical plan. If the plan is discharge to home after ECV, then lower dose bupivacaine may be best. If the plan is delivery immediately after ECV (either Cesarean or induction depending on the ECV outcome), then larger dose (7.5mg or 10mg) bupivacaine may be best.
— Stephanie Goodman, MD
Columbia University Medical Center
- Magro-Malosso ER, Saccone G, Di Tommaso M, Mele M, Berghella V: Neuraxial analgesia to increase the success rate of external cephalic version: A systematic review of meta-analysis of randomized controlled trials. Am J Obstet Gynecol 2016; 215: 276-86.
- Chalifoux LA, Bauchat JR, Higgins N, Toledo P, Peralta FM, Farrer J, Gerber SE, McCarthy RJ, Sullivan JT: Effect of intrathecal bupivacaine dose on the success of external cephalix version for breech presentation: A prospective, randomized, blinded clinical trial. Anesthesiology 2017; 127; 625-32.
- Carvalho B, Bateman BT: Not too little, not too much: Finding the goldilocks zone for spinal anesthesia to facilitate external cephalic version. Anesthesiology 2017; 127; 596-8.
For more information:
- Please listen to Dr. Carolyn Weiniger’s excellent podcast on ECV. https://www.openanesthesia.org/podcasts/soap-obstetric-anesthesia-podcast/
The transversus abdominis plane (TAP) block is a regional technique providing sensory blockade of the abdominal wall. Analgesia is achieved by targeting anterior rami of spinal nerves that travel between the internal oblique and transversus abdominis muscles. Several variations exist. 1
TAP blocks may be most beneficial when intrathecal morphine is contraindicated or solely inadequate. As part of an opioid-sparing, multimodal analgesic regimen, TAP blocks may be performed at any point during the perioperative period. 2,3 The technique is considered low risk and with few complications. Unable to block visceral pain, TAP blocks cannot provide intra-abdominal surgical anesthesia alone.
–Kristin Brennan, MD
Penn State Health System
- Ng SC, Habib AS, Sodha A et al. High-dose versus low-dose local anaesthetic for transversus abdominis plane block post-caesarean delivery analgesia: a meta-analysis. Br J Anaesth 2018: 120(2): 252-263.
- Mcdonnell JG, Curley G, Carney J, et al. The analgesic efficacy of transversus abdominis plane block after caesarean delivery: a randomized controlled trial. Anesth Analg 2008;106:186 – 191.
- Jadon A, Jain P, Chakraborty S et al. Role of ultrasound guided transversus abdominis plane block as a component of multimodal analgesic regimen for lower segment caesarean section: a randomized double blind clinical study. BMC Anesthesiol 2018; 18; 53.
For more information:
- Abdallah FW, Halpern SH, Margarido CB. Transversus abdominis plane block for postoperative analgesia after caesarean delivery performed under spinal anesthesia? A systematic review and meta-analysis. Br J Anaesth 2012; 109(5): 679 – 87.
- Blanco R, Ansari T, Girgis E. Quadratus lumborum block for postoperative pain after caesarean section. Eur J Anesthesiol 2015; 32:812 – 818.
- Young MJ, Gorlin AW, Modest VE and Quraishi SA. Clinical implications of the transversus abdominis plane block in adults. Anesthesiol Res Pract 2012; 2012: 1-11.
Accidental Dural Puncture and Postdural Puncture Headache
Since epidural blood patch (EBP) is the gold standard therapy for post-dural puncture headache (PDPH), it has been postulated that administering autologous blood prior to epidural catheter removal after known or suspected dural puncture could prevent PDPH altogether. In 2004, a randomized trial found that prophylactic EBP did not significantly reduce the incidence of PDPH, maximum pain scores, onset time, or days spent unable to perform childcare compared to sham EBP. However, prophylactic EBP did decrease the duration of PDPH symptoms.1 In 2014 another study showed a reduction of PDPH in patients who received prophylactic EBP, yet it is unclear if randomization and mode of delivery affected these results. As EBP is not without risks, the most severe of which includes arachnoiditis, prophylactic EBP administration is not recommended. Conservative management (hydration, caffeine, migraine medications) and therapeutic EBP should be the mainstays of therapy.
Thomas R. Gruffi, MD
Mount Sinai West Hospital
- Scavone BM, Wong CA, Sullivan JT, Yaghmour E, Sherwani SS, McCarthy RJ, Efficacy of a prophylactic epidural blood patch in preventing post dural puncture headache in partuients after inadvertent dural puncture. Anesthesiology 2004;101:1422-7.
- Stein MH, Cohen S, Mohiuddin MA, Dombrovskiy V, Lowenwirt I. Prophylactic vs therapeutic blood patch for obstetric patients with accidental dural punctue – a randomized controlled trial. Anaesthesia 2014;69:320-6
- Agerson AN, Scavone BM. Prophylactic epidural blood patch after unintentional dural puncture for the prevention of post-dural puncture headache in parturients. Anesthesia and Analgesia 2012;115:133-6.
The decision to place an intrathecal catheter (ITC) or to re-site the epidural catheter after an accidental dural puncture (ADP) should be a risk-benefit clinical judgment, depending on these factors:
- The efficacy of ITCs – According to a 6-year retrospective cohort review of 235 parturients who had an ADP during epidural placement, ITC were associated with a higher rate of failed analgesia1.
- The difficulty of placement – For a very difficult epidural placement where the risk of an additional ADP and the failure to intubate is high (e.g. morbidly obese parturient), placing an ITC over resiting might be the better choice3. However, frequent checks for functionality is critical.1,3
- The side effect profile – According to a retrospective review of 218 patients over a 10-year period, there was no difference in the incidence of postdural puncture headache between the resited epidural group and the spinal catheter group.2
Onyi C. Onuoha, MD. MPH
Perelman School of Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA
- Jagannathan DK, Arriaga AF, Elterman KG, Kodali BS, Robinson JN, Tsen LC, Palanisamy A.
Effect of neuraxial technique after inadvertent dural puncture on obstetric outcomes and anesthetic complications. Int J Obstet Anesth. 2016 Feb; 25:23-9. doi: 10.1016/j.ijoa.2015.09.002. Epub 2015 Sep 18.
- Bolden N, Gebre E. Accidental dural puncture management: 10-year experience at an academic tertiary care center. Reg Anesth Pain Med. 2016 Mar-Apr;41(2):169-74. doi: 10.1097/AAP.0000000000000339.
- Soens MA, Birnbach DJ, Ranasinghe JS, van Zundert A. Obstetric anesthesia for the obese patient: an ounce of prevention is worth more than a pound of treatment. Acta Anaesthesiol Scand. 2008 Jan; 52(1):6-19. doi: 10. 111/j. 1399-6576.2007.01483.x.