Situations of disaster, whether due to natural disaster or man-made disaster, are non-discriminatory. All individuals are affected equally, whether male or female, young or old. Persons who are providing medical care in an area affected by disaster may come across patients who are pregnant and in need of urgent care. Obstetric care along with injury-related care is considered among the forefront of necessary surgical services in disaster situations. The need for anesthetic care is recognized as an integral component of these hospital services.¹ In the United States, 99% of all births occur in a hospital or clinical setting, which may be inaccessible and severely damaged during the inciting disaster. During times of stress, women experience increased risk of health complications associated with pregnancy, including stress-induced premature labor and birth, low birth weight infants, and neonatal and infant death.¹

In a disaster setting, in many facets and not just medically, focus shifts from the care of individuals to care for the greater good. Finite resources should be distributed to the largest number of patients, prioritizing those with the greatest potential benefit. Medical practitioners providing care during a disaster need to be more aware of the fact that they are not functioning within a vacuum and their decisions for care of one patient may impact several others. If a provider is faced with an overwhelming number of patients and has limited supplies for placement of epidural or spinal anesthesia and analgesia, we would recommend prioritizing more critical laboring patients (Table 22.1). Conditions which may signify priority may include: patients undergoing trial of labor after cesarean (TOLAC), patients with known difficult airways, and patients with pre-eclampsia.

This list is by no means all-inclusive, and the situation should be gauged by the practitioner at the bedside. However, these situations represent cases where a rapid anesthetic delivery option may be advantageous due to propensity for obstetric emergencies.

Personnel also need to ensure that they continue to be able to provide care to as many patients as possible, meaning that practitioners need to provide adequate self-care. For example, during Hurricane Harvey in Houston, Texas, practitioners attempting to arrive at their hospitals flooded their vehicles and waded to their workplaces.

As a general rule, in obstetric anesthesia, general anesthesia is to be avoided due to worsening of airway concerns in the parturient and its effects on the neonate. [Editor’s note: Ketamine has been found to be useful in low-resource countries.] However, in disaster circumstances, additional consideration will need to be made for placement of a neuraxial anesthetic. Unless there is a situation which necessitates spinal or epidural anesthesia, it is good for the practitioner to remember that ultimately, labor epidurals are elective procedures and may not be necessary in an austere circumstance. Advocating for natural birthing may be warranted if there are not sufficient supplies for all patients to receive epidurals, or if there is a shortage of available skilled staff for neuraxial anesthesia or analgesia.

In a disaster setting, there will be multiple ways in which stress is placed on medical providers and hospitals in general. There may be situations in which some hospitals must evacuate their patients to a hospital in a safer location. This will place a strain on the receiving location’s supply of manpower, equipment, and medications. The incoming supply will hopefully not be limited or strained due to the safe location presumed to not be affected by disaster. This was evident in Louisiana during Hurricane Katrina, where roughly 30 hospitals were made to evacuate their patients to hospitals in safer locations. Receiving hospitals required additional staff and additional supplies to function and handle the unusual load of patients.

Other hospitals may not be able to evacuate and may be required to shelter in place. This was the situation for many hospitals in Texas during Hurricane Harvey. This created a scenario in which supply of medications, manpower, food, and medications were strained and had to be conserved. In Houston, Texas, supplies of preferred local anesthetics for spinal anesthesia dwindled, and care coordination with obstetricians was necessary. Only emergent or urgent surgeries were able to be performed, so that medications were not used and potentially wasted for elective cases.

During Hurricane Katrina, Keesler Medical Center offered shelter in the hospital to patients who were 36 weeks pregnant or greater. Parturients at earlier weeks of gestation were also admitted if they were defined as a high-risk pregnancy: cases of placenta previa, pre-term labor, or hypertensive disorders. The increase in admitted patients placed strain on medical staff and supplies. It also required obstetricians and anesthesiologists to shelter in place at the hospital. Space may be a limitation in this scenario, and has been experienced by many hospital staff in locations prone to natural disasters such as hurricanes.

In Corpus Christi, Texas, during Hurricane Harvey, patients were transferred from a hospital with a labor and delivery unit to another hospital further from the floodplain, which did not have a labor and delivery unit. Anesthesia staff who were relocating to the safer hospital transported as many supplies as they could in their private vehicles. This included a supply of emergency medications, spinal and epidural trays, intubating equipment, and bag-mask ventilation equipment. At night, as the storm hit the city, cesarean sections were performed in cardiac operating rooms with generator power.

There may be multiple shortages which lead to a provider’s inability to place an epidural for a laboring patient in a disaster situation. They could be shortages in personnel, supplies, or medications. Personnel may need to work in shifts and provide each other with significant moral support to endure the experience. Medications may need to be substituted as availability of preferred agents dwindles. Attention will need to be paid closely to multidose vials and sterile technique to ensure preservation of medications.

Due to the current conditions of local anesthetic shortages in the United States, the Society for Obstetric Anesthesia and Perinatology (SOAP) has issued recommendations for next-line therapy when hyperbaric bupivacaine hydrochloride 0.75% in a volume of 1.5 to 2 ml is not available. Lower doses should be used if one is able to also administer neuraxial opioids:.

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  Isobaric bupivacaine hydrochloride preservative-free 0.5% for a dose between 12 and 15 mg.

  
  
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  Tetracaine can also be used for spinals, in a concentration of 1% with a dose of 7 to 9 mg depending on the patient’s height. Attention should be paid to the increased duration of tetracaine, to possibly 3 hours or more.

  
  
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  Lidocaine can be used, if anesthesia is not required for more than about one hour. The concentration recommended by SOAP² would be 5%, with a dose of 50 to 75 mg, once again depending on the patient’s height.

  
  
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  Mepivacaine is not recommended in the obstetric patient due to a long half life in the neonate.

  
  
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  Prilocaine is also not recommended due to the risk of methemoglobinemia.

  
  
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  The ED50 for spinal hyperbaric bupivacaine was found in one study to be 1.58 mg.³

  
  
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  If using hyperbaric ropivacaine for spinal anesthesia, the ED50 of this has been shown to be 14.22 mg.³

In the case of a labor epidural, the preferred agent would be isobaric preservative-free bupivacaine hydrochloride 0.25% in an appropriate volume for the clinical situation; lower volumes for epidural bolusing, higher volumes for initiation of neuraxial analgesia. SOAP states in their advisory statement that ropivacaine is also able to be used for epidural labor analgesia, but that it is 40% less potent than bupivacaine.⁴

If surgical anesthesia is needed through an epidural route, both preservative-free lidocaine 2% with or without preservative-free epinephrine and chloroprocaine can be used if the surgery is emergent. If there is time available to allow for the slower onset of bupivacaine or ropivacaine, these could be used instead to provide surgical anesthesia through the epidural. Keep in mind that with continued usage of lidocaine over a prolonged period of time, tachyphylaxis can develop. Combined spinal epidural techniques or dural puncture epidural techniques may also allow for a reduction in required doses of local anesthetic and less bolusing by providers.⁵

Continuous spinals for labor analgesia may be an interesting option for practitioners attempting to conserve resources, as the volume of local anesthetic needed to provide anesthesia or analgesia will be decreased. Requiring smaller volumes of local anesthetic may be ideal in a situation of limited medication supply. However, increased incidences of hypotension and post-dural puncture headache (PDPH) may ultimately require greater time and attention from the practitioner. However, if used appropriately and with appropriately monitored patients, this could be a viable option. The situation would need to be evaluated closely by the practitioner providing care at the time. If an intrathecal catheter is placed, it needs to be very thoroughly labeled as such. Consequences of bolusing an intrathecal catheter with epidural doses could be catastrophic: this could result in total spinal anesthesia, need for endotracheal intubation, or need for immediate cesarean delivery of the fetus.

There are some reports of using transversus abdominus plane (TAP) blocks for surgical anesthesia in cases where patients cannot tolerate either a neuraxial or a general anesthetic. The TAP blocks reported were performed with 20 to 30 ml of local anesthetic on each side; choice of local anesthetic was determined by the attending anesthesiologist. Two patients reported received 20 ml of 0.25% bupivacaine hydrochloride, and a third patient received an equal mixture of 1% lidocaine and 0.25% ropivacaine.⁶ Another report describes a cesarean section performed with local anesthesia for a patient in whom a neuraxial was inappropriate and general anesthesia would not have been tolerated; 8 ml of 0.5% bupivacaine were injected into the skin at the location of incision, and 6 ml were injected into the rectus sheath for abdominal closure. The surgeons were mindful not to use any retractors or packing, because of the lack of visceral anesthesia. The patient received only a total of 30 μg of fentanyl during the 45 minute procedure.⁷ The American College of Obstetricians and Gynecologists (ACOG) has stated that infiltration of local anesthesia can be used for cesarean delivery if there is a situation where general anesthesia or neuraxial anesthesia is not available.⁸

Ability to treat PDPH and potentially perform epidural blood patches may need to be prepared for in the case of disaster. The incidence of PDPH will likely not decrease during the time of disaster, and practitioners will need to be prepared to treat it. It would be unacceptable to allow patients to suffer with this condition, placing them in a situation where they may not be able to care for their newborn infant in a disaster. Allowing PDPH to continue and develop sequelae would also not be ideal in a situation of limited resources. Conservative measures that can be used to treat PDPH include: acetaminophen alone, a combination of acetaminophen, butalbital, aspirin, and caffeine, increased fluid intake, flat positioning, and sphenopalatine ganglion block. Sphenopalatine ganglion block can be easily performed if the practitioner can obtain concentrated lidocaine, either 2% or 4%, and cotton swabs. The cotton swabs are soaked in lidocaine, and then advanced to the back of the nose above the middle turbinate until they meet the posterior wall of the nasal cavity. This is left in place for 10 minutes on each side and then repeated with an additional lidocaine-soaked cotton swab bilaterally.^9,10 If none of these conservative measures result in resolution of PDPH, the practitioner may need to perform an epidural blood patch. The decision for this procedure would depend on the clinical condition of the affected patient, and availability of supplies. The risks and benefits of the procedure would need to be weighed against using an epidural kit for placement of a blood patch, which another laboring patient may need for neuraxial anesthesia.

Laboratory values may not be able to be obtained at all or may be significantly delayed, so laboratory evaluation of coagulation may not be possible before placing neuraxial anesthetic. During Hurricane Harvey in Houston, Texas, Ben Taub Hospital experienced flooding of its basement laboratory, making lab tests unobtainable for practitioners. Discretion of the anesthesiologist had to be used. Trauma or another disaster scenario could have resulted in significant blood loss or development of coagulopathy. The American Society of Anesthesiologists (ASA) practice guidelines issued in 2016 indicate that an intra-partum platelet count is not required in the healthy parturient, but the decision to obtain a platelet count should be left to the discretion of the anesthesiologist based on the patient’s medical history.¹¹

Elective cesarean sections should be postponed as long as possible to allow the disaster circumstance to abate. Discharge of patients after care may be difficult during this time, thus reducing patient volume will be advantageous for staff and others who may need emergency care. Patients being discharged home will have a newborn to care for, and this may be less than ideal in the setting of a natural disaster or other traumatic circumstance. However, postponing patients may result in development of obstetric emergencies, such as uterine rupture during labor after previous cesarean, or shoulder dystocia of large birth-weight infants. Providers will need to be prepared for emergency circumstances and the potential for patients to present in extremis. Labor and neuraxial placement may be occurring in atypical areas, such as emergency departments or in triage settings. Postponing cesarean sections may require implementation of additional monitoring of the mother. If equipment is in short supply, these may be simple monitors such as fetal movement and fetal heart rate Doppler, if standard fetal heart rate and uterine tone tracings are not available.

Equipment may also in short supply during these circumstances. Epidural pumps for continuous infusions may not be available. Epidurals may need to be bolused intermittently to provide analgesia. This will allow for greater spread and less use of local anesthetic, as well. The required volume for intermittent bolusing without a continuous infusion would likely be between 10 and 20 ml, depending on the height of the patient, and higher concentrations will be needed for more dense blocks, depending on the clinical scenario. For labor analgesia, 10 to 20 ml of 0.1% ropivacaine or 0.125% bupivacaine with or without opioids would likely be sufficient for most patients. One study to obtain the EC50 for labor analgesia was 0.065% for bupivacaine with a volume of 20 ml, and 0.37% for lidocaine in a volume of 20 ml.¹² This technique will require more time and attention from the practitioner, but may be the only option, if there is a shortage of pumps or if they are unable to be operated due to lack of battery power or electricity. Generators in the basement or ground levels of hospitals may be easily affected by natural or man-made disasters.

Peripheral nerve block techniques may also be useful during a time of reduced supply of equipment and pain medications. Pudendal or perineal blocks may be performed by obstetricians before delivery, and may alleviate the need for neuraxial placement by anesthesiologists, who may be spread thin due to non-obstetric surgical emergencies or staffing intensive care units. The pudendal block is performed trans-vaginally and with the patient in lithotomy position. The physician palpates the ischial spine and introduces a needle about half an inch to pierce the sacrospinous ligament. After negative aspiration, a 10 ml volume of local anesthetic is injected. This process is repeated on the opposite side.

Alternative therapies for laboring mothers may also be helpful to reduce the need for anesthesia care of the laboring patient. The standard breathing exercises, massage, and white noise that are standard in current labor and delivery care should continue to be employed as available, as they may help alleviate further strain on anesthesia care for analgesia.

The knowledge of anesthesia staff is indispensable during time of disaster, even when caring specifically for the obstetric patient. Our specialty is known for its ability to care for patients who need definitive line placement, resuscitation with blood products or fluids, or acute airway management. Recent studies have shown that use of tranexamic acid for prevention of obstetric hemorrhage is beneficial.¹³ Not only would this be useful for individual patients, but would also be helpful in the setting of disaster or mass casualties, where blood products must be conserved. The obstetric patient in a disaster scenario may be more likely to require this type of attention than the usual obstetric patient encountered in our standard day-to-day practice.

Allocation of staff may need to be considered during the disaster. Anesthesiologists may need to fulfill other roles as needed: replenishing supplies as a technician, performing secretarial duties, transporting patients, or performing administrative tasks. Reasonable standards of care and training should not be ignored, but during times of stress and decreased availability of the aforementioned facets of care, mid-level providers will naturally be relied upon to extend the care of the physicians whose direction they are functioning under. This will include delegation of tasks to nurse anesthetists, anesthesiologist assistants, nurses, and anesthesia technicians.¹⁴