Early definitions of artificial intelligence (AI) started with Alan Turing's question in his landmark paper on computing machinery and intelligence—"Can machines think?".[1] In the last two decades, AI and its real-world implementation have made great strides. A more current understanding of AI delineates four categories: human-like behavior, rational decision-making, internal thought processes, and external intelligent expression. Each, some, or all of these domains can be developed to achieve a chosen objective.[2] The three components of AI that are utilized in the medical field are machine learning (ML), neural networks, and deep learning. ML implies making machines smarter by enabling them to learn, predict, and adapt from past behavior. Neural networks and deep learning are components of AI that teach computers to process data similar to the workings of the human brain. A network consists of a sheet of "nodes" that receive and process information; if the result crosses a "threshold," it passes on data to the next sheet of nodes. This process can be designed to continue through multiple layers (sheets of nodes) to further refine output and simultaneously give feedback to improve its own processes. Deep learning models can pick up complex patterns in media, writing, and other data to provide insights and predictions. There are four main areas where AI can become important and useful in obstetric anesthesia and analgesia. These are optimizing pre-procedure parturient assessment (especially airway), faster and higher success rates in epidural and spinal analgesia or anesthesia, predicting and preventing hemodynamic crises, ensuring optimal drug administration, and refining pain management.[3,4] All these can improve the quality and delivery of obstetric anesthesia. AI can play an important role in preoperative risk stratification and airway assessment of parturients presenting for analgesia or surgery to an anesthesiologist. AI has been used for prediction and risk assessment in a variety of surgical procedures.[5] ML algorithms using maternal and ultrasonographic parameters obtained during pregnancy have been used to predict the possibility of an emergent cesarean section during active labor.[6,7] In the future, perhaps all pregnant women could be appropriately counseled if studies can use similar algorithms across different races and ethnicities.[6] Another ML-based algorithm MySurgeryRisk is able to predict the risk for eight postoperative complications—acute kidney injury, sepsis, venous thromboembolism, intensive care unit admission for more than 48 hours, need for mechanical ventilation for more than 48 hours, wound, neurological, and cardiovascular complications.[8] If a similar ML-based algorithm is made with data from parturients, it could prove very useful to predict the need for an expert anesthesiologist or intensivist opinion, the possibility of developing postpartum hemorrhage, or other serious complications after anesthesia. This would enable the timely shifting of patients to higher care centers and decrease maternal morbidity and mortality. A thorough literature search does not reveal quality studies regarding the use of AI for risk stratification of patients undergoing labor pain relief interventions or cesarean sections. Airway assessment and difficult airway in a parturient are very important concerns for all anesthesiologists. Pregnant patients may need a general anesthetic for non-obstetric procedures during pregnancy or delivery-related procedures. It is common knowledge that airway management in this subpopulation may be complicated by physiologic changes in pregnancy, the high risk of aspiration, and the need to avoid any morbidity to both mother and unborn baby. In clinical practice, standard airway assessment tools such as the Mallampati score are used; however, clinical assessment alone is not a good predictor of difficult intubation in parturients.[9] Ultrasound has been used for both prediction and airway management in anesthesia. A recent systemic review of clinical evidence concluded that many ultrasound parameters alone or in combination might be useful in predicting difficult laryngoscopy or difficult intubation (although data on difficult mask ventilation were scarce).[10] There have also been reports of ultrasound usage in comparing airway assessment in healthy parturients, patients with preeclampsia, and nonpregnant patients. In one of the first studies regarding this, the authors concluded that airway parameters as assessed by an ultrasound differ significantly between pregnant and nonpregnant patients. Parturients had a significantly higher hyomental distance, anterior neck soft tissue thickness at the hyoid and vocal cord level, and oral cavity height, while the tongue thickness and mandibular condylar movements were significantly lower than in nonpregnant patients. Similar results were reported in patients with preeclampsia.[11,12] These are early findings, and each of these studies was conducted on less than 100 women. Applying such data to AI-based algorithms could play a vital role in airway assessment and prediction of difficult airway in pregnancy. The most challenging aspect of this is likely to be the need for massive data collection. There have been a few reports where convolutional neural networks have used images of patients and compared them to existing data for difficult airway risk assessment.[13,14] Once such AI algorithms are broadly available, they could be very useful for obstetric anesthesiologists. One of the greatest challenges that an anesthesiologist faces is that of performing spinal or epidural anesthesia in parturients, especially when obese. Other than obesity, the difficulty is increased by pregnancy-induced changes in the spine, difficulty in positioning, and the decreased ability to keep still during the procedure due to painful contractions during labor. It is not uncommon nowadays to routinely use ultrasound for regional and neuraxial blocks due to its real-time, low-cost, and radiation-free capabilities. However, nerve tracking and accurate needle localization remain an ongoing challenge due to noise interference, artifacts, and anatomic variability.[15-17] AI techniques have been developed to help in determining the needle insertion point using automated spinal landmarks based on ultrasound imaging of the lumbar spine. Using this, a very high (80%) first-attempt success rate has been reported.[18] Furthermore, AI in the form of convolutional neural networks has been designed to study and learn from large data sets of epidural ultrasound anatomy. This information has been used in real time to optimize the ultrasound image, overlay labeled anatomy onto the patient or on-screen (augmented reality), estimate epidural space depth, and even guide needle placement. This has been shown to reduce procedure time and needle redirections and provide better success rates than the palpation method.[19,20] Another use of AI is in estimating optimal drug doses, such as when administering vasopressors and calculating spinal local anesthetic doses. Closed-loop systems are likely to be used more often in the future. In a closed-loop system, a target is set by the operator, which is automatically maintained by varying the amount of medication administered based on patient information, drug properties, and monitored values. This has several advantages: greater precision in achieving targeted outcomes, reducing the possibility of human error, and freeing the anesthesiologist to focus on higher-level tasks. These have been used successfully in the treatment of hypotension during obstetric anesthesia; blood pressure below a set threshold starts a vasopressor infusion, which is automatically stopped, reduced, or increased based on response.[21-23] The results have been very encouraging, but the devices have still not gained popularity. The intrathecal local anesthetic dose for cesarean section varies and is usually dependent not only on various anatomical and physiological parameters of the parturient but also on the personal preferences of anesthesiologists. A recent study was one of the first to use an ML algorithm for calculating the intrathecal hyperbaric bupivacaine dosage based on patients' physical variables before cesarean section. The authors developed a decision model using abdominal girth and vertebral column length to predict the dose of intrathecal bupivacaine that would provide optimal levels of spinal anesthetic blockade for a cesarean section.[24] Future studies and clinical implementation may determine whether such dose calculations are of any clinical significance. Labor analgesia with patient-controlled epidurals (PCEA) can be augmented using AI algorithms to increase or decrease basal infusion rates in proportion to changes in patient demand. This can be taken one step further by maintaining baseline levels using calculated volume intermittent boluses instead of a continuous infusion; this has been shown to increase epidural spread and analgesic efficacy. A similar system has been designed for use with patient-controlled intravenous remifentanil labor analgesia, with safeguards that reduce or stop the infusion if there are adverse respiratory or hemodynamic effects.[23] Safety is a cornerstone of anesthesia practice, and AI is a core component of new clinical tools being developed for predicting adverse intraoperative events. Most important among these are hypoxemia and hypotension during a cesarean section, which can affect not only the mother but also the baby. The literature has innumerable reports regarding the best vasopressor, its dose, the mode—bolus or infusion—and the timing to be used to treat post-neuraxial hypotension. However, the prediction of this hypotension and hypoxemia using AI in obstetric anesthesia is still to be explored. The initial AI-related reports were from data collected from nonpregnant subjects. An ensemble model-based ML tool, named "Prescience," has been used to predict intraoperative hypoxemia. This model was unique in that it was able to delineate the risk factors that contributed to its prediction, thus avoiding the "black box effect" (when AI provides useful information but does not explain how or why).[25] The system was trained using minute-by-minute data from the electronic medical records encompassing fifty thousand surgeries and improved the performance of anesthesiologists when providing interpretable hypoxemia risks and contributing factors. More recently, a transferable embedding method (one that transforms time-series signals into input features for prediction with ML models) with data from intensive care unit (ICU) and operation rooms has been evaluated to predict multiple outcomes: hypocapnia, hypoxemia, hypertension, hypotension, and the administration of phenylephrine and epinephrine.[26] The results were very encouraging in both reports. In one of the few studies on parturients, the authors compared the capabilities of a single hidden neural network layer of 12 nodes to those of a discrete feature discrimination approach in predicting significant hypotension under spinal anesthesia during cesarean section.[27] The results were very encouraging, but again more data need to be collected. A few clinical trials implementing AI prediction of post-induction hypotension in cesarean sections under spinal anesthesia are being conducted presently, and one is still recruiting patients.[28] Initial AI-based studies on predicting the incidence and duration of intraoperative hypotension and subsequent effectiveness of treatment with vasopressors have shown promise, but more research is needed to assess the real-world usefulness of these in clinical practice and their impact on postoperative outcomes. These principles can be greatly beneficial in emergency obstetric anesthesia as there is often no time for effective clinical evaluation. Other methods used by AI are an interpretation of various arterial blood pressure waveform points to detect early cardiovascular deterioration. Noninvasive (finger cuff) pulse contour analysis by neural networks has been able to warn for hypotension following spinal anesthesia in obstetric patients and has guided pressor use.[27] Additional anesthetic complications such as postoperative nausea and vomiting can also be anticipated.[28] The main basis of an efficient AI system is data acquisition, and getting this from parturients is likely to have many ethical and legal issues. Informed consent, privacy, ownership, transparency, data quality, and data protection are important concerns that still need to be addressed. This would require not only collaboration between medical bodies but also a commitment from political heads of different countries. Furthermore, industries need to manufacture and market AI-based medical technology to increase availability. Overall, a big push to AI would be required for it to become meaningful in the developing world, where data acquisition is still in its infancy. India can play an important role in acquiring these obstetric data, as it continues to have a high fertility rate. Ideal AI-based equipment to complement the obstetric anesthesiologist should cover five domains: firstly, a difficult airway prediction system that analyses the patient's facial images and compares it to a database; secondly, a device that assists neuraxial anesthesia by detecting and labeling anatomical landmarks while also guiding needle placement in real time; thirdly, a prediction system for hemodynamic instability after neuraxial blockade along with closed-loop systems that auto-infuse the optimal amount of vasopressors titrated to response; and lastly, a closed-loop system for epidural or intravenous labor analgesia incorporating pain scores, hemodynamic stability, respiratory effects, and fetal status. It is also imperative to teach the principles of AI as part of the anesthesia resident curriculum—for future anesthesiologists—and to have AI-related continuing medical education for the present generation of anesthesiologists. In conclusion, AI in anesthesia will surely complement traditional methods of clinical decision-making and treatment in a few years, but for an obstetric anesthesiologist it is still a long wait!
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