Anesthesia management houston Archives - Xenon Health

Preventing and Managing Postoperative Delirium

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Delirium, a fluctuating state of inattention and disorganized thinking, is often seen in elderly hospitalized patients and the critically ill. It is distinct from emergence delirium, a separate phenomenon seen in young children emerging from anesthesia, which will not be discussed here. Postoperative delirium in the adult population carries a significant burden of morbidity, and its prevention and treatment should be familiar to anesthesia providers.

Identifying patient risk factors is important to stratify who may be at risk for postoperative delirium. Preoperative factors include advanced age, disease severity, previous neurological disease (e.g. Alzheimer’s), preexisting psychiatric disease, and substance abuse. Intraoperative factors include surgical complexity, anesthetic medications and dosages, and large variations in blood pressure, temperature, and hematocrit. Postoperative causes include certain medications (benzodiazepines are notorious for causing delirium), sleep deprivation, immobility, and prolonged ICU and/or mechanical ventilation duration.

Several standardized scoring methods have been validated in both intubated and non-intubated patients, primarily in the ICU, however they are seldom used by practitioners. Among these scoring systems, the confusion assessment method for the ICU (CAM-ICU) and the Intensive Care Delirium Screening Checklist (ICDSC) have been deemed the most valid when compared to the gold standard (DSM-IV criteria).

Anesthesia providers can help prevent postoperative delirium by avoiding benzodiazepines in patients at risk, and using opiates judiciously (though they can cause confusion in elderly or neurologically compromised patients, they can also treat pain, a known trigger of delirium). Dexmedetomidine is a promising agent in delirium prevention, having decreased the incidence of ICU delirium when compared to sedation with propofol or midazolam infusions. A single 0.5mg/kg dose of ketamine has been shown to decrease the incidence of postoperative delirium. Titrating anesthetic dosages according to Bispectral Index (BIS) has also been shown to decrease postoperative delirium.

Prophylactic use of antipsychotic drugs has not been shown to be helpful in delirium prevention. Also lacking evidence of efficacy is the use of cholinesterase inhibitors, arising from the theory that the etiology of delirium lies in acetylcholine deficiency in the brain. Using antipsychotic agents such as haloperidol and seroquel for the treatment of delirium is currently standard of care, but there is little evidence these medications reduce either the duration or severity of symptoms. The atypical antipsychotic olanzapine, on the other hand, has shown some efficacy in decreasing the incidence of delirium. As always, QT monitoring should be observed while administering these medications.

Ultimately, nonpharmacologic measures such as patient reorientation, sleep protocols, and early mobilization are the most inexpensive and lowest risk ways to combat postoperative delirium. Implementing these measures as standard of care for at-risk patients can be an important step to decreasing the incidence and duration of postoperative delirium.


Evans AS, Weiner MM, Arora RC, et al. Current approach to diagnosis and treatment of delirium after cardiac surgery. Annals of Cardiac Anaesthesia. 2016;19(2):328-337. doi:10.4103/0971-9784.179634.

Siddiqi N, Harrison JK, Clegg A, Teale EA, Young J, Taylor J, Simpkins SA. Interventions for preventing delirium in hospitalised non-ICU patients. Cochrane Database of Systematic Reviews 2016, Issue 3. Art. No.: CD005563. DOI: 10.1002/14651858.CD005563.pub3.

Update on the Perioperative Surgical Home (PSH) Model

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A year ago, we wrote on the perioperative surgical home (PSH) model, a treatment paradigm that appoints the anesthesiologist as the main coordinator of care from the preoperative to perioperative phase. To summarize, the PSH model is utilized to increase efficiency and minimize cost throughout the care continuum.

Academic and research sites such as UC Irvine and University of Alabama were early adopters of the PSH model. In 2014, UC Irvine concluded a clinical study on the impact of PSH within primary joint replacement surgery practices. Researchers found that patients treated within the PSH model were associated with lowered readmission rates throughout 30 days post-surgery to statistical significance[1]. University of Alabama corroborated these results with their early stage study, finding that integration of PSH resulted in lower healthcare costs and increased efficiency in allocation of resources after the integration of PSH[2].



Given the positive results of early PSH studies, other academic institutions have sought to explore PSH in practical settings. For example, physician researchers at the Ochsner Health System in Louisiana recently developed a modified PSH model. In the Ochsner PSH model, anesthesiologists and orthopedic specialists worked in tandem as the main coordinators of care for patient subgroups[3]. To facilitate communication between each therapeutic side, specialists met weekly to discuss the patient pathway. By the end of treatment, Ochsner researchers found that the PSH treatment group was associated with improved outcomes and lowered costs, with an approximate savings of several hundred dollars per patient. Furthermore, patients in the PSH model did not present with worse clinical outcomes than control. In sum, the Ochsner study presents a strong case for the PSH model as a potential lever for increasing quality of care on a patient basis, while also pushing up value and driving costs down.

In multiple instances of the PSH model, anesthesiologists have served as physician leaders to great success. With expertise in multiple domains of the patient experience, anesthesiologists are strong candidates to remain at the forefront of the integration of the PSH model nationwide. As the healthcare field moves towards an emphasis on value-based care, anesthesiologists will prove to be essential leaders in PSH model applications as well as further optimized models of care.

Update: The American Academy of Physical Medicine and Rehabilitation officially endorsed the PSH model on October 12, 2017[4], further supporting the increased importance of PSH as a viable and efficient model for integration into healthcare institutions nationwide.

[1] http://www.anesthesiology.uci.edu/psh.shtml

[2] https://bmcanesthesiol.biomedcentral.com/articles/10.1186/1471-2253-13-6



State Patient Compensation Funds for Medical Malpractice

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While many specialty providers will face a medical malpractice suit at one time in their careers, anesthesiologists are higher on the risk spectrum to be subject to a claim. Anesthesiologists continue to be subject to among the highest of medical malpractice claims, with an average paid indemnity of about $100,000.[1] There are a variety of reasons that a patient may submit a claim against an anesthesiologist, and these reasons are heightened with a dramatic event during an unsuccessful surgery: for example, an airway collapse or a drug overdose. While the most likely reason for a patient to submit a claim against an anesthesiologist is due to injury, patients may also submit claims based on actions of medical error, lack of medical information on the part of the patient, or failure to treat.[2] When considering medical malpractice in the anesthesia field, it is also necessary to consider the role and responsibilities of Certified Registered Nurse Anesthetists (CRNAs).  CRNAs are often under the supervision of anesthesiologists or surgeons, such that in an event of potential medical malpractice the supervising physician is held responsible.[3] However, national regulations do exist to address claims against CRNAs.  In most states, the typical liability limit for CRNAs are $1,000,000 per claim and $3,000,000 total.[4] CRNAs may also participate in a medical malpractice insurance plan offered by his or her associated hospital network. Overall, the medical malpractice space is more highly dependent on individual claims, as little precedent has been set for the CRNA case.



In cases of medical malpractice, including for anesthesia services, the government may step in to resolve medical malpractice claims between the patient and the physician. On a state basis, Patient Compensation Funds (PCFs) are utilized in cases of medical malpractice. Essentially, these funds grant compensation to patients and/or patient’s families that have fallen subject to a medical error or omission by a physician that is in the associated state PCF system. The state then agrees to allocate and manage the PCF by collecting insurer surcharges and enrolling physicians in the fund. The state also designs specific methods to decide how and to whom the PCF can be granted.[5] For example, New Mexico, Nebraska, Wisconsin, and Indiana have specific caps in place to restrict the individual or total award amounts granted by the Fund. More qualitative regulations may also be in place, such as in South Carolina, which requires the patient to receive specific medical information about the course of the case before formally pursuing the claim. Ideally, PCFs act as an important middleman, providing for the effective release of compensation to the patient while also minimizing social and financial impact on the provider. PCFs are therefore an effective tool to continue improving the paradigm of care in the healthcare system, thus ensuring that patients are provided for, and that physicians are encouraged to continue to raise the standard of care.

[1] https://www.insurance.wa.gov/sites/default/files/documents/2016-med-mal-annual-report.pdf

[2]  http://www.medscape.com/features/slideshow/malpractice-report-2015/

[3] https://biotech.law.lsu.edu/books/lbb/x943.htm

[4] http://www.aana.com/insurance/Documents/understanding-crna-malpractice-insurance101-practice.pdf

[5] http://via.library.depaul.edu/cgi/viewcontent.cgi?article=1396&context=law-review

Expanesthetics: Anesthesia Research Meets Venture Capitalism

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Expanesthetics is an expanding startup dedicated to an ambitious goal: to discover new inhalational anesthetic agents that have “improved qualities and a reduced side effect profile.” It aims no higher than to revolutionize the field of inhaled anesthetics, with potentially the same effect as the fluorinated hydrocarbons had in the 1940s when they largely eclipsed older anesthetics such as ether or chloroform. It’s an attractive and somewhat unique sales pitch, and the company claims to be the only one of its kind to be investing in research and development for the next generation of inhaled anesthetics.

How exactly Expanesthetics plans to accomplish this formidable goal is outlined in general terms on their website: to utilize a patent-pending screening platform to identify molecules with potential anesthetic and analgesic properties, and to test these molecules for potential utility as general anesthetics. It purports to have access to licensed and proprietary libraries of molecules from which to conduct the screens. The exact nature of the screening platform and its parameters for identifying promising molecules is not stated outright, which is understandable since it is the basis of their enterprise. The mechanism of action of modern inhaled anesthetics in general is one of the great unsolved questions of the past half century, and if Expanesthetics has indeed made a breakthrough into what makes them tick, the potential applications are not to be underestimated.


Expanesthetics is the brainchild of Dr. Robert Brosnan, a professor in the Department of Surgical and Radiological Sciences at the UC Davis School of Veterinary Sciences. According to Brosnan, his laboratory discovered a “plausible molecular mechanism of action” for current anesthetic agents, allowing him make predictions on novel agents and their interactions with specific receptors. A search of PubMed for Brosnan yields collection of anesthetic molecular and animal-based research, the most recent of which describes the anesthetic synergy between N-butane and n-pentane. It’s solid research, detailed, rigorous and transparent. Whether it has any relation to Brosnan’s discovery that prompted him to start Expanesthetics is unclear.

One challenge Expanesthetics has put forward is the question, “is what we have good enough?” In other words, why revolutionize a field that isn’t broken? In the arena of research and development, this question doesn’t really seem to have a place. Horses must have seemed just fine before the first cars came along, and what anesthesiologist has not lamented the vasodilatory properties of our current inhaled anesthetics when pushing pressors after induction? It remains to be seen what fruits will yield from this ambitious startup, but raising nearly $20 million in the name of anesthesia research is an impressive feat worth keeping an eye on.




Postoperative Pain Management After Cesarean Delivery

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Cesarean delivery, the most commonly performed major surgery in the United States, is often conducted under neuraxial anesthesia, however epidurals are routinely removed immediately after operation and spinals wear off within hours. Effective perioperative pain management relies on a multimodal approach to avoid complications such as delayed functional recovery, impaired maternal-fetal bonding, increased postpartum depression, and persistent chronic pain – all associated with poor perioperative pain control. Incisional and pelvic pain may persist beyond 6 months after surgery in up to 18% of patients, at incidences higher than associated with vaginal deliveries but lower than non-obstetric surgeries.

Neuraxial anesthesia is preferable to general anesthesia in regards to prevention of persistent pain after cesarean birth, unsurprising as severe acute postoperative pain is one of the strongest predictors of the development of chronic pain. Single shot spinal anesthetics are the most common method, with epidural and combined spinal-epidural anesthetics as alternatives.  While continuing epidural analgesia after the immediate postoperative period may be a viable option for high-risk patients (i.e. those with preexisting chronic pain), routine use risks increased thromboembolic events due to decreased mobility, increases costs, and burdens nursing staff.

Neuraxial (intrathecal or epidural) morphine has a longer half-life than more lipophilic opiates such as fentanyl, with a duration of action from 14 to 36 hours. The optimal dose is unclear, with escalating doses (>100mcg) leading to increased side effects such as nausea, vomiting and pruritus. Respiratory depression can occur, but was not observed in studies reviewed in a 2016 meta-analysis. Even in women with risk factors for respiratory depression (e.g. obstructive sleep apnea), neuraxial opiates are still recommended over IV opiate administration.

Scheduled non-steroidal anti-inflammatory medications and acetaminophen is recommended in all patients undergoing cesarean delivery unless contraindicated (e.g. postpartum hemorrhage would preclude the use of NSAIDs). NSAIDs decrease opiate use by 30-50%, and acetaminophen by 20%.

Wound infiltration of local anesthetics can reduce pain scores and opiate use for up to 48 hours postoperatively, with continuous infusion via subfascial catheters placed intraoperatively being more effective than single dose techniques. These catheters offer more mobility than epidural catheters, but only treat somatic and not visceral pain.

Transversus abdominis plane blocks are another option for somatic pain, significantly improving postoperative pain and reducing opiate consumption in patients under general anesthesia or when neuraxial morphine was not used. It is also a viable rescue technique in severe acute postoperative pain. The duration of effect of single shot TAP blocks is 6-12 hours.

Postoperative pain control after cesarean delivery should be a priority, with a multimodal approach being recommended to reduce maternal and fetal exposure to opiate medications and prevent the development of persistent postoperative pain.


Carvalho BButwick AJ. Postcesarean Delivery Analgesia. Best Pract Res Clin Anaesthesiol. 2017 Mar;31(1):69-79. doi: 10.1016/j.bpa.2017.01.003.