key: cord-279480-nqp1pc9v
authors: Ring, Laurence E.; Martinez, Rebecca; Bernstein, Kyra; Landau, Ruth
title: What Obstetricians should know about Obstetric Anesthesia during the COVID-19 pandemic
date: 2020-08-26
journal: Semin Perinatol
DOI: 10.1016/j.semperi.2020.151277
sha: 
doc_id: 279480
cord_uid: nqp1pc9v

The COVID-19 pandemic has prompted obstetric anesthesiologists to reconsider the ways in which basic anesthesia care is provided on the Labor and Delivery Unit. Suggested modifications include an added emphasis on avoiding general anesthesia, a strong encouragement to infected individuals to opt for early neuraxial analgesia, and the prevention of emergent cesarean delivery, whenever possible. Through team efforts, adopting these measures can have real effects on reducing the transmission of the viral illness and maintaining patient and caregiver safety in the labor room.

"There are no emergencies in a pandemic." -Colloquialism "There were only emergencies in a pandemic, it turned out." -Lili Loofbourow

The 

The first reported clinical cases resembling COVID-19 infection were reported in November 2019 in Hubei Province, China, with the number of global confirmed cases topping 4 million world-wide by mid-May, 2020. Unlike previous viral pandemics, COVID-19 incidence, prognosis and maternal and neonatal outcomes do not appear to be worse in pregnant women compared to that in the general population. 2 Because symptoms of COVID-19 in parturients can be similar to those seen during early or prolonged labor, COVID-19 infection may be concealed by symptoms of labor. This has practical implications for the approach to women admitted to Labor and Delivery Units. With the increased availability and speed of SARS-CoV-2 testing, institutions have widely advocated for universal testing of women admitted for labor and delivery. 3 If testing capacity allows, this approach should be strongly considered even in areas of lower prevalence.

As the pandemic has evolved, a significant proportion of women have tested positive for COVID-19 infection in the absence of symptoms. 4 The infectivity of these patients is unclear.

However assuming that asymptomatic, positive patients can spread the disease, risk mitigation strategies suggest that all patients, until tested negative, are presumptive positive and possibly infective. The general recommendations which follow for care of the COVID-19 infected pregnant woman should also apply to patients under investigation (PUIs). (Table 1 ) Otherwise healthy COVID-19 infected parturients who are asymptomatic or mildly symptomatic require no additional laboratory testing prior to neuraxial placement and should be treated as per general recommendations prior to neuraxial labor analgesia placement. In pregnancy, a platelet count of 75,000 x 10 6 /L or above is considered to be associated with an extremely low risk of spinal epidural hematoma after a neuraxial procedure. 6, 7 For patients with moderate to severe symptoms of COVID-19 infection, pre-placement laboratory tests should be considered, as thrombocytopenia, although rare and usually not severe, 8 and prolongation of tests of coagulation have been reported.

As with all interactions, a COVID-19 infected parturient should maintain a mask over her mouth and nose during the placement of neuraxial analgesia. Placement of neuraxial analgesia is not considered an aerosolizing procedure, hence only droplet and contact, and not airborne, precautions should be followed by all caregivers in the room. One exception may be the support person, usually a nurse, who is holding the patient during placement, as that person"s may be close to the parturient"s face. That support person may wish to reposition away from the patient"s face, or consider following airborne precautions (notably an N95, or similar, mask).

For all COVID-19 positive patients, a constant consideration of the anesthesiologist should be to uphold standards of care and patient safety while minimizing caregiver exposure.

Neuraxial analgesia infusions can be modified to maintain a safety profile and also minimize the need for physician administered dosing of epidural catheters (top-ups). By increasing the local anesthetic concentration in the epidural infusion, adding adjuvants (e.g. clonidine), and/or by increasing the rate or volume of the infusion, the anesthesiologist can increase the density of the block, reducing the need for top-offs. 1 These strategies should be cautiously carried out to avoid maternal hypotension hence, these alterations may not be appropriate in all cases.

There should be added emphasis on assuring that an epidural catheter in a COVID-19

infected parturient is well-secured and well-functioning at all times. While the epidural"s functionality is the responsibility of the anesthesiologist, evaluation by all care teams of the effectiveness of neuraxial analgesia should be encouraged. Compared to standard care in noninfected patients, the anesthesiologist may be more likely to replace a questionably functional epidural catheter in COVID-19 infected patients, in hopes to avoid urgent situations that may increase the odds for patient adverse outcomes (e.g. accidental dural puncture during a replacement of epidural catheter, or general anesthesia if urgent cesarean delivery) or avoidable exposures for healthcare providers (rushed replacement of neuraxial analgesia/anesthesia or general anesthesia in the operating room).

Patients with moderate to severe COVID-19 symptoms will likely require a modified approach to the maintenance of neuraxial labor analgesia. Depending on the severity of the disease, this may include continuous pulse oximetry and placement of an arterial catheter for frequent blood gas analysis. Patients with significant but stable disease and labor which is progressing may continue to be candidates for vaginal delivery, but changes in symptoms, including shortness of breath, increasing oxygen requirements, and/or decreasing PaO 2 or increasing acidemia should be triggers to reconsider mode of delivery.

Inhaled nitrous oxide (N 2 0) has re-emerged as a popular option for labor analgesia, either early, as a bridge prior to neuraxial labor analgesia, or for second stage pain relief in women with no neuraxial labor analgesia. 9 However, in the context of the pandemic, it is not currently recommended. First, there is insufficient data regarding appropriate cleaning of the apparatus.

Second, potential aerosolization of the virus during administration suggest the risks outweigh the benefits of this modality. 5 Third, a parturient using inhaled N 2 O will not be able to wear a surgical face mask, which exposes healthcare providers, as well as support people allowed in the labor room. Last, inhaled N 2 O during labor may cause nausea and vomiting, considered to be an aerosol generating event, 10 which may further contribute to viral transmission.

In the general population, opioid-based intravenous patient-controlled analgesia (PCA) is inferior to neuraxial analgesia for labor analgesia, and carries significant risks for both mothers and babies. 11, 12 Its downsides are even more pronounced in COVID-19 infected parturients.

Maternal sedation and respiratory depression in a patient with impaired oxygenation and ventilation may exacerbate hypoxia and hypercarbia. These physiologic disturbances may not be well tolerated by the parturient or fetus and may lead to direct or indirect fetal depression increase the risk of cesarean delivery. Delivery Units will be caring for patients of unknown COVID-19 status with some frequency, the latter strategy will likely make more sense.

The guiding principles of preparing an operating room for a SARS-CoV-2 infected patient are two-fold. First, it should be taken into account that an aerosol-generating procedure or event may occur (Box 1). The risk of exposure is probably most directly borne by the anesthesia team due to their proximity to the patient"s face and mouth, but is shared by all operating room personnel. In the United States, about 5% of cesarean delivery are done under general anesthesia, 16, 17 and although this prevalence can likely be reduced with practice changes noted above, at times urgent general anesthesia may be required. For this reason, it is strongly The anesthesiologist may consider increasing the dosage of the local anesthetic in the neuraxial solution and/or adding adjuvants (e.g. clonidine, higher dose of morphine) with the idea that these actions would prolong the duration of the anesthetic, a protection against needing general anesthesia should the case last longer than expected. 1 An early publication from China posited that "exaggerated" hypotension may occur with neuraxial anesthesia in women with SARS-CoV-2 infection. 21 However this conclusion has been widely questioned since prevention of hypotension is standard of care, and doesn"t seem to have been practiced as part of the study. 22 Supplemental oxygen should not be used unless specifically indicated (SpO2<95% prior to delivery 5 or SpO2<90% or lower after delivery) as this is an aerosol generating procedure. 23 If supplemental oxygen is needed, the patient should wear a surgical mask over the nasal cannula or face mask.

The anesthetic plan for cesarean delivery of a woman with COVID-19 infection with more significant symptoms (hypoxemia requiring FiO2>50%, moderate to severe acidemia, and/or the need for vasopressors) requires modifications to the above approach. In patients with severe disease, respiratory rate is usually elevated (often more than 35 breaths per minute), individual breaths are shallow, and the patient is using accessory muscles of respiration causing increased work of breathing. Arterial blood gas analysis in these patients often reveals a metabolic or mixed metabolic/respiratory acidosis, decreased carbon dioxide and a large alveolar-arterial gradient. The ability of these patients to maintain their oxygen saturation while spontaneously breathing is often precarious; the anesthetic approach must strive to interfere with respiratory drive and mechanics as little as possible.

An arterial line should be placed before the induction of anesthesia in order to facilitate frequent arterial blood gas analysis, as well as close monitoring of blood pressure. Neuraxial anesthesia can still be employed in many of these patients, but a single shot spinal anesthesia might not be recommended. The standard spinal anesthetic technique involves a single large dose of local anesthetic (typically hyperbaric bupivacaine 0.75% -12-15mg) and opioid adjuvants to achieve a reliable, quick onset block. The rapid onset of a spinal block also leads to peripheral vasodilation and hypotension and standard practice is to prevent and manage with vasopressors (usually a phenylephrine infusion). 24 However the rapid onset of a single shot spinal might not be well tolerated in a patient who already has some degree of inflammatory mediated vasodilation.

Additionally, the rapid onset of thoracic dermatomal level (usually to T4) weakening the accessory muscles of respiration, may cause the patient to decompensate. Finally, a single-shot spinal technique will not allow prolonged post-cesarean pain management.

Either an epidural block or a combined spinal epidural (with low dose spinal) would be an appropriate neuraxial technique for a patient with significant COVID-19 infection. The benefits of these techniques in the context of a potentially hemodynamic and respiratory compromise is the slower onset and titratable response. The relatively titratable nature of these neuraxial anesthetics should allow the anesthesiologist to incrementally dose the epidural catheter to achieve (and maintain) an anesthetic level adequate for surgery but which minimizes motor block to the accessory muscles of respiration. The downside of an epidural-based anesthetic is that it is not quick to place or dose, and it may not achieve the same density of block as a spinal anesthetic.

Speed is often a critical component of anesthetic care on the Labor and Delivery Unit.

During the time of the pandemic, general discussions as well as patient-specific communications amongst care team members with regard to this issue are a crucial aspect of patient and provider safety. Prior to entering the operating room, personnel must be given time to properly don PPE.

Different strategies may be useful to ensure quick, and correct, selection and application of PPE including: 1) appropriate placement of PPE near operating rooms with instructive signage 2) simulations or practice sessions on PPE use and 3) a team member to serve as a "spotter,"

checking each individual"s donning effort before he or she enters the operating room.

Outside of the pandemic, for truly emergent operating room cases, general anesthesia is often a consideration. Because of the risk of caregiver exposure during an intubation, SARS-CoV-2 infection has forced a difficult reassessment of under what circumstances general anesthesia is required. Based on pooled data evaluating pathogens" transmission during severe SARS outbreaks, the odds of infection for healthcare providers during tracheal intubation was 6.6-fold higher compared to that among providers not exposed to intubation. 25 As mentioned previously, efforts must be made to encourage neuraxial analgesia placement and avoid emergent cesarean delivery in patients with SARS-CoV-2 infection, whenever possible.

If there does need to be a cesarean delivery on a patient who does not have an epidural catheter and is COVID-19 positive, the anesthesia team will need to weigh the risk of general anesthesia, including the risk staff exposure, to the possible risk of delay due to placement of a neuraxial block (typically a single shot spinal). This is an ethically fraught question, as safety of the care team is not amongst the usual concerns when considering a care plan for a patient on

Labor and Delivery Unit. In experienced hands, a spinal placement may take no longer than induction of general anesthesia, and "rapid sequence spinal" is definitely an option in emergencies, 26 particularly in the setting of a difficult airway. 26 Even in the setting of fetal distress, the putative 2-3 minutes that may have been saved between arrival into the operating room and the time of delivery do not justify the increased risk of a general anesthetic, 27, 28 in this case for both mothers and healthcare providers.

If general anesthesia does become necessary either before or during the course of a cesarean delivery, several safety measures should be followed. 29 after the block, usually a phenylephrine infusion, and by the use of prophylactic antiemetics. [31] [32] [33] In addition, there is growing evidence that uterus exteriorization during cesarean delivery significantly increases intraoperative nausea and vomiting and should in general be avoided, 34 

Specific anesthesia considerations for cesarean delivery in the patient with SARS-CoV-2 infection 1. Minimize the necessity for general anesthesia (preoperatively or intraoperatively) 2. Spinal anesthesia is the preferred anesthetic if rapid onset is desired 3. Combined-spinal epidural (or epidural if indwelling catheter) may be preferred if slow titration is desirable

Minimize the odds of intraoperative nausea and vomiting -phenylephrine infusion -antiemetics (ondansetron, metoclopramide) -avoidance of uterine exteriorization

Multimodal opioid-sparing analgesia should be initiated as per ERAC protocols -Acetaminophen 650mg q6h -Ibuprofen 600mg q6h (unless specifically contraindicated) -Oxycodone 5mg for breakthrough pain

Obstetric Anesthesia During the COVID-19 Pandemic

Clinical course of severe and critical COVID-19 in hospitalized pregnancies: a US cohort study

COVID-19 infection among asymptomatic and symptomatic pregnant women: Two weeks of confirmed presentations to an affiliated pair of New York City hospitals

Universal Screening for SARS-CoV-2 in Women Admitted for Delivery

Lumbar neuraxial procedures in thrombocytopenic patients across populations: A systematic review and meta-analysis

Risk of Epidural Hematoma after Neuraxial Techniques in Thrombocytopenic Parturients: A Report from the Multicenter Perioperative Outcomes Group

Neuraxial procedures in COVID-19 positive parturients: a review of current reports

Pro-Con Debate: Nitrous Oxide for Labor Analgesia

Droplet fate in indoor environments, or can we prevent the spread of infection? Indoor Air

A Survey of Intravenous Remifentanil Use for Labor Analgesia at Academic Medical Centers in the United States

Remifentanil for labor analgesia: an evidence-based narrative review

Don't throw the baby out with the bathwater: spinalepidural hematoma in the setting of obstetric thromboprophylaxis and neuraxial anesthesia

The Society for Obstetric Anesthesia and Perinatology Consensus Statement on the Anesthetic Management of Pregnant and Postpartum Women Receiving Thromboprophylaxis or Higher Dose Anticoagulants

Adverse Events and Factors Associated with Potentially Avoidable Use of General Anesthesia in Cesarean Deliveries

General Anesthesia for Cesarean Delivery: Occasionally Essential but Best Avoided

Safety and efficacy of different anesthetic regimens for parturients with COVID-19 undergoing Cesarean delivery: a case series of 17 patients

French Obstetric Anesthesia Working G. Spinal anesthesia for Cesarean delivery in women with COVID-19 infection: questions regarding the cause of hypotension

Neuraxial anaesthesia and peripheral nerve blocks during the COVID-19 pandemic: a literature review and practice recommendations

International consensus statement on the management of hypotension with vasopressors during caesarean section under spinal anaesthesia

Aerosol generating procedures and risk of transmission of acute respiratory infections to healthcare workers: a systematic review

Rapid sequence spinal anaesthesia for category-1 urgency caesarean section: a case series

Mode of anaesthetic for category 1 caesarean sections and neonatal outcomes

General anaesthesia for emergency caesarean delivery: is the time saved worth the potential risks?

A randomized trial of phenylephrine infusion versus bolus dosing for nausea and vomiting during Cesarean delivery in obese women

Antiemetics added to phenylephrine infusion during cesarean delivery: a randomized controlled trial

Spinal-induced hypotension: Incidence, mechanisms, prophylaxis, and management: Summarizing 20 years of research

Uterine Exteriorization Compared With In Situ Repair of Hysterotomy After Cesarean Delivery: A Randomized Controlled Trial

Uterine exteriorization compared with in situ repair for Cesarean delivery: a systematic review and meta-analysis