Dosing of Neuraxial Anesthesia Blocks for Obese Patients

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Obesity is a nationwide epidemic, affecting over 30% of Americans. Over 50% of pregnant women in the United States are overweight or obese. Neuraxial anesthesia is often a good choice for this population for appropriate surgeries as well as for labor, avoiding airway instrumentation and complications of general anesthesia that are often exacerbated by obesity.

It remains a topic of debate whether the dosage of local anesthetics for neuraxial blocks needs to be adjusted for obese patients. Traditional teaching based on earlier studies recommends decreasing the dose of local anesthetics for spinal and epidural blocks, citing a positive correlation between cephalad spread of sensory blockade and BMI. However newer data calls this correlation into question.

MRI studies demonstrate a smaller cerebrospinal fluid volume in the lumbar subarachnoid space of obese patients, as well as an inverse relationship between lumbar CSF volume and cephalad block extension. The epidural space in these patients is also smaller. The mechanism is thought to be compression and increased abdominal pressure by abdominal fat, which causes caval compression, epidural vein engorgement, and displacement of soft tissue through the intervertebral foramina.

Despite these confirmed physiological differences between obese and non-obese patients, several recent clinical studies have shown no significant difference in the ED50 and ED95 of hyperbaric spinal bupivacaine in obese parturients and those with normal BMI when undergoing cesarean section. There is little data on super-obese patients (BMI >50 kg/m2). Some argue based on these studies that intrathecal dosing of local anesthetics need not be reduced for obese patients, however there is no expert consensus on the topic.

Less controversy exists in the epidural dosing of obese patients, with most studies showing a decreased requirement for local anesthetics in this population.

The fact that block overdose, block failure and inadequate block duration in obese patients may lead to undesirable emergency airway instrumentation in a population with increased incidence of difficult airway raises the stakes of accurate dosing. Options such as combined spinal epidurals allow for dosage reduction in the initial intrathecal component, with the ability to titrate together with the epidural component. This and intrathecal catheters both guard against the possibility of longer surgical duration in patients with high BMI.

While it remains unclear whether obesity warrants a reduction in local anesthetic dosing for neuraxial anesthesia, a prudent approach may be to start on the side of safety and begin with smaller dosages while employing a catheter-based technique.



Brodsky JB, Lemmens HJ. Regional anesthesia and obesity. Obes Surg. 2007 Sep;17(9):1146-9.

Lamon AM, Habib AS. Managing anesthesia for cesarean section in obese patients: current perspectives. Local Reg Anesth. 2016 Asug 16;9:45-57. doi: 10.2147/LRA.S64279.

Panni MK, Columb MO. Obese parturients have lower epidural local anaesthetic requirements for analgesia in labour. Br J Anaesth. 2006 Jan;96(1):106-10.

Guides to Preventing Medical Malpractice

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Medical malpractice claims are increasingly a prominent issue in the United States healthcare system. By the historical legal definition, medical malpractice refers to a legal suit which centers on a healthcare practitioner’s alleged breach of his/her professional medical duty to the patient. Furthermore, the person who brings forth the suit must be able to prove that this breach caused more than negligible harm, including proof of significant injury that led to damages.

Across the spectrum of healthcare providers, anesthesiologists and certified registered nurse anesthetists (CRNAs) are among the specialists with the highest number of malpractice claims nationwide. Research shows that approximately a third of anesthesiologists will encounter at least one medical malpractice suit resulting in an indemnity payment, over a six-year time period. Furthermore, indemnity payments related to anesthesiology-based medical malpractice claims are often high-cost. Anesthesiologists comprise the third largest bucket of physicians that are held liable to pay higher than a million dollars in one medical malpractice claim. The significance of the financial burden incurred to the practitioner, along with the trickle effects that influence the professional reputation of the physician, underlines the critical nature of this issue to anesthesiologists and CRNAs that practice in the United States.

So, which types of medical episodes are most likely to result in medical malpractice claims against anesthesia healthcare providers? The Advanced Institute for Anesthesia Practice Management reports that nearly half of all anesthesia medical malpractice suits are associated with anesthesia for dental procedures. The next highest number of claims result from deaths that occurred due to or as a result of improper anesthesia administration. Lastly, a small proportion of claims result from issues such as nerve damage, tissue injury, infection, surgical complications, extended pain, burns, or errors in medication administration.

Medical malpracticeTo prevent the onset of medical malpractice claims, anesthesia providers such as anesthesiologists and CRNAs should follow the below guidance, based on advice from experts in the field:

  1. Informed, holistic consent is necessary to prevent future claims. If a patient does not feel comprehensively informed about the procedure, including the potential symptoms during recovery time, he/she is much more likely to feel a sense of betrayal and confusion after the procedure. To ensure informed consent, anesthesiology practitioners should maintain that support staff such as research coordinators, registered nurses, and even physicians are trained on how to deliver ethical, culturally sensitive, informed consent to every patient who walks in the door before the procedure.
  2. Focus on increased documentation pre, during, and post-surgery. While documentation requirements are already heavy, it is essential that anesthesiologists and CRNAs have extensive records at their disposal in order to prepare for any potential outcome during the procedure. Moreover, extensive documentation is the best practice from the management perspective as well, for analyzing past medical episodes to determine patterns of care or potential factors that may influence the outcomes of surgeries. In this field, information is essential.
  3. If a mistake is made, consider mediation. Even in a highly fixed setting such as the operating room, mistakes occur because of sleep deprivation or human error. If a mistake was undeniably made by a practitioner in the OR, it is useful to remain open to mediation with an independent third-party mediator. Mediation is a modern conflict resolution practice that is rising in relevance as physicians and patients begin to realize the negative spiral of engaging in endless arbitration. With mediation, the two parties can settle on a financial payment that both believe is fair for the claim. Moreover, if the practitioner is willing, in the mediation setting patients have the option to receive an apology, a practice that is nearly impossible in the arbitration setting.

Errors can happen, even in the most controlled of circumstances such as an OR. However, anesthesia professionals and healthcare administrators can use tools such as the above to circumvent the onset of medical malpractice claims, allowing practitioners and patients to work together towards a peaceful and healthy future.




Safety of Anesthesia for Children Under Three

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Children who require anesthesia services before the age of three represent a broad range of medical diagnoses and circumstances. Regardless of how serious a child’s situation may be, there has been a longstanding concern in clinical medicine around the potential risks of receiving anesthesia at such a young age. Much of this concern has stemmed from animal studies where drugs used in general anesthesia show neurological consequences for young subjects. Some observational studies of humans who were exposed to anesthesia drugs at a very young age also report correlations with behavioral and neurodevelopmental issues. The questions raised in these studies are deeply troubling: are children who require anesthesia at a young age at risk of lifelong neurological setbacks? This is a troubling price to pay for safe and painless medical interventions in a highly vulnerable population.

A groundbreaking study released recently from researchers at the Mayo clinic shows results that should be encouraging for patients, their families, and the anesthesiologists who care for them. Dr. David Warner led a team of researchers in evaluating Minnesotan children via the Mayo Anesthesia Safety in Kids (MASK) study. The basic question this study aimed to answer was: do children who require multiple procedures facilitated by general anesthesia have a higher risk of adverse neurodevelopmental outcomes?

Anesthesia for Children

Much to the relief of researchers and clinicians alike, this rigorous cohort study suggests that the answer is no. The study mainly tracked children for differences in IQ, a useful barometer for adverse neurological impact. Also, it used screening and parental reporting to identify any behavioral or learning-related issues. This provided a holistic picture of many possible risks to the mental well-being of children who receive anesthesia before the age of 3. Results indicated that children with such exposure to anesthesia were not associated with lower IQs compared to children who had no anesthesia before age 3. With regard to the behavioral and learning issues, children with a single anesthesia experience also had no increased risk. However, children with multiple anesthesia experiences had slightly more reported learning and reading difficulties from parent accounts.

In studies like these, it is always difficult to know for certain whether potentially confounding factors have been appropriately accounted for. On a basic level, children who require medical interventions multiple times at a very young age likely have other differences from children who do not beyond their anesthesia exposure. It is nearly impossible to say whether the anesthesia are the determinant of the slight delay in reading, for example, or whether it is on account of an early childhood disrupted by medical challenges.

This research could have useful implications for hospital and larger-scale policies. Follow-up and coordination of services for medically complex children is an enormous area for growth and development. Medical science is ensuring the survival and thriving of more and more children with complex medical conditions that emerge at birth or early childhood. However, this population has particular needs and vulnerabilities that our health system should tend to in a serious manner. Ensuring their basic safety in using the necessary drugs to give them access to crucial surgeries and procedures is an important first step in their lifelong well-being. It’s also important to attend to any potential behavioral and cognitive challenges that children may face—if anesthesia drugs are not predisposing children to these outcomes, we may consider looking to other potential causes. One of the causes may be that parents of children with medical needs are lacking necessary supports in meeting learning benchmarks in the midst of their higher-stakes caregiving demands.



Warner, Zaccariello, Katusic, Schroeder, Hanson, Schulte, . . . Flick. (2018). Neuropsychological and Behavioral Outcomes after Exposure of Young Children to Procedures Requiring General Anesthesia: The Mayo Anesthesia Safety in Kids (MASK) Study. Anesthesiology, -.


Ultrasound-guided Dry Needling

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The opioid epidemic and its potential solutions have been a key focus in the medical and political arena. Exploring alternative and adjuvant pain management techniques is vital to decreasing narcotic prescription, and as anesthesia providers it behooves us to familiarize ourselves with these techniques in our continued efforts to provide analgesia to our patients.

One such technique is dry needling of myofascial trigger points, a familiar procedure in the world of chronic pain that is only recently being explored as a useful treatment in acute pain. Centers such as St. Joseph’s University Medical Center in Paterson, NJ (which was recently featured on NPR) have incorporated ultrasound-guided dry needling into programs designed to cut down prescription of opioid medications in the emergency department. Together with regional blocks, lidocaine patches, and other non-opiate adjuvants, St. Joseph’s program is seeing results as it enters its second year. Some ED physicians may go an entire shift without prescribing a single narcotic.

The concept of trigger point dry needling is simple. Myofascial trigger points, defined as “hyperirritable points in skeletal muscle that are associated with a hypersensitive palpable nodule in a taut band,” are targeted with a needle under ultrasound guidance to “break up” or deactivate the point. Local anesthetic may or may not be injected after needling to blunt the pain of the actual procedure. The technique is inexpensive, relatively simple to learn, and carries with it low risks of complications. However due to the poorly understood pathogenesis of trigger points and their associated syndromes, it is not a technique that is widely employed.

Evidence is abundant in the scientific literature for the use of trigger point dry needing for the short-term relief of myofascial pain. A recent meta-analysis reviewed randomized controlled trials from the year 2000 to 2015 and found that trigger point dry needling improved pain relief, range of motion and quality of life in the short term. Long term effectiveness was unclear, as was the effect on amount of analgesic medications taken, disability, and sleep.

Further studies are needed to better elucidate these questions, perhaps with better standardized procedures and higher methodologic quality of randomized controlled trials. For now, the short-term effects of ultrasound-guided dry needling of myofascial trigger points is promising, and may become a useful tool in the treatment of acute and chronic pain.



Espejo-Antúnez L, Tejeda JF, Albornoz-Cabello M, Rodríguez-Mansilla J, de la Cruz-Torres B, Ribeiro F, Silva AG. Dry needling in the management of myofascial trigger points: A systematic review of randomized controlled trials. Complement Ther Med. 2017 Aug;33:46-57. doi: 10.1016/j.ctim.2017.06.003. Epub 2017 Jun 15.

Non-obstetric Surgery During Pregnancy

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In 2016, more than 6 million women in the United States gave birth, transforming daughters into mothers and relationships into families.1 All patients are strongly encouraged to receive routine antepartum care with an obstetrician after pregnancy is confirmed. This includes laboratory tests, ultrasound and monitoring of the baby’s growth and activity, supportive measures to optimize nutrition and maternal comfort, and preventative therapy (including immunizations, smoking and alcohol cessation) to avoid untoward medication exposures and ensure a safe pregnancy.

A common question that arises relates to the safety of anesthesia and surgery during pregnancy. In general, all elective surgical procedures are typically postponed until at least several weeks after giving birth, to decrease both the risk to the mother as well as the unborn baby. Regardless, more than 75,000 pregnant females undergo surgery every year.2 Related risks can be broken down into 3 categories:

Risk to mother: Starting at week 6, significant changes in the maternal physiology occur in order to compensate for the baby’s developing circulatory system and nutritional needs. Increased blood volume leads to the heart working harder and faster. The lungs need to supply enough oxygen to meet the metabolic demands of a growing womb in an increasingly limited space. As the plasma or “water” component of the blood increases, the complex reactions that activate and eliminate our medications also change. The anesthesiologist must take these factors into account when planning an anesthetic for an emergency or urgent procedure.

Still, maternal risk for non-obstetric surgery is minimal and not significantly different than that of the general population. In a systematic review of more than 12,000 patients, a single death was reported.3 However, every patient should receive a thorough evaluation for factors related to “high-risk pregnancy,” characterized by significant cardiovascular, metabolic or other systemic changes that put the mother at risk during or immediately after pregnancy.

Risk to fetus: Between weeks 3 and 8, the baby’s organs start to develop from embryonic tissue implanted in the uterus. This is a critical stage with an intricate, orchestrated sequence of events, and any interruptions can lead to birth defects. A classification system exists to determine the safety of medications in pregnancy.4

Anesthetic medications have been studied extensively in pregnant females, with the vast majority of studies showing no difference in the incidence of birth defects compared to the general “background” risk of 3-5% after the first trimester.5 These same studies emphasize the importance of limiting exposure to the shortest possible duration, avoiding repetitive dosing, and waiting until after the first trimester. Prolonged exposure to anesthetic adjuncts such as benzodiazepines and nitrous oxide can lead to defects, and opioid medications such as fentanyl can lead to dependence and abstinence syndromes after the baby is born. All patients are strongly encouraged to discuss potential medication additions or changes with their obstetrician or primary care provider.

Non obstetric surgery during pregnancy

Risk to pregnancy: Even after the organs have formed and first heartbeat is heard, there is a slight increase in the incidence of ectopic pregnancy, miscarriage, and pre-term labor with pregnant patients receiving an operation. The rate of miscarriage is 5.8% after surgery, which is increased to 10.5% if surgery is performed during the first trimester.3  Severe changes in blood pressure, hypoxia (low oxygen), acidosis, and presence of infections are the most immediate causes associated with adverse outcomes.

For this reason, surgery is recommended to be performed in the 2nd trimester. Below are some precautions that are taken for female patients that are pregnant, or suspected to be pregnant, upon admission to the hospital:

  1. Determination of necessity and urgency: While elective surgery is postponed, urgent and emergent procedures are needed to ensure maternal well-being, which takes a priority over the fetus in the case of medical or surgical emergencies. For example, appendectomies (i.e. removal of the appendix due to infection and inflammation) are performed because the risk of severe infection (e.g. sepsis) or rupture would threaten the mother and fetus. Trauma and the resulting changes in blood pressure and sympathetic system activation can also compromise circulation to the fetus, and thus surgery must occur.

Anesthetic choice is relevant to avoid unnecessary exposure of narcotics to the mother and fetus, and a regional anesthetic (e.g. epidural, nerve block, local skin infiltration) can help achieve minimal risk.

  1. Routine pre-operative pregnancy tests: All female patients of childbearing age are typically required to take a urine pregnancy test as part of the pre-operative evaluation. If positive, a sample from the blood is taken to confirm pregnancy and estimate conceptual age.
  2. Fetal monitoring: Starting in the 2nd trimester, special electrodes and pads can be used to monitor the mother’s baby’s heart rate during surgery. In hospital settings, an obstetric consultant or team will be present to monitor fetal well-being and intervene if the pregnancy is deemed to be at risk.
  3. Emergency Protocol: Although CPR and similar life support measures are extremely rare, a strict protocol is followed for all pregnant female patients with unstable vital signs. The patient is tilted slightly to the left (“left uterine displacement”) to decrease the pressure exerted by the womb on the major blood vessels returning blood from the legs to the heart. If the