Childbirths are now the most common reason for hospitalization in Canada. Subsequently, cesarean delivery is becoming increasingly more common, representing 30% of all child deliveries. In addition, epidural analgesia now accounts for 60% of operative deliveries. Historically, most studies regarding anesthetic experience of infants and maternal individuals focus on mortality. Fortunately, recent analysis has shown the number of patients dying from anesthesia care has severely decreased, likely due to improvement with specialty training, airway management, airway monitoring, regional anesthesia use, and the standardization of safe practices through analysis and research. In order to improve neonatal and maternal care, the extent, frequency, and risk factors for anesthesia-related incidences must be assessed.
The study conducted by Baghirzada et al analyzed data from all jurisdictions excluding Quebec through the use of a national database, the Canadian Institute of Health Information Discharge Abstracts Database, over the course of 13 years. This study analyzed ~2.6 million hospitalizations and 3.2 million anesthesia interventions. The authors reported anesthesia-related incidences were rare (261.7 per 100,000 interventions; 95% CI, 256.1-267.4) and decreased over time. Cesarean deliveries experienced significantly more complications than vaginal deliveries, especially when general anesthesia was used alone or in conjunction with neuraxial anesthesia. These results demonstrate a favorable medical system. However, additional information regarding the applications of these results and the limitations of the study are needed.
Data Abstractsors utilize the International Classification of Diseases, 10th Revision with Canadian Enhancements to retrospectively assign disease codes to hospital charts after discharge. This requires a multistep process including disease recognition, documentation, identification and interpretation, and correct assignment involving at least one physician and data Abstractsor. As mistakes during any part of this process results in misclassifications, datasets must be validated through additional studies. Because of discrepancies in results and validation was not mentioned, it is a strong possibility that the study did use verified data. Especially considering the large population and the small number of patients who experienced adverse incidences, data could be skewed. In addition, many results provide no further insight into changes to hospitals as feasible recommendations require detailed data sets. Readers should proceed with caution while drawing conclusions.
Additional efforts toward improving care include the identification of important factors, improvements within individual countries, and recommendations for future data sets and studies. Postoperative pain intensity at 24 hours, incidence of postoperative nausea and vomiting, quality of recovery, time to gastrointestinal recovery and mobilization, and sleep disturbance are important patient-comfort measurements to utilize in future research. Furthermore, previous studies have identified serious and frequent complications including high neuraxial block, respiratory arrest, and unrecognized spinal catheterization. However, recommendations based on these outcomes became difficult or impossible to implement in other locations of the world. Subsequently, The World Health Organization recommends the use of anesthesia outcome measurements, such as the Core Outcome Measures for Perioperative and Anesthesia Care or Standardized Endpoints for Perioperative Medicine to identify patient’s comfort level and improve overall care. It is time to move beyond defining success in obstetric anesthesia as surviving pregnancy and avoiding adverse events during delivery. Quality of obstetric anesthesia and patient-centered outcomes should be our focus.
The authors describe the anesthesia-related complications in obstetric patients in Canada over a 13-year period. They reviewed over 2.6 million hospitalizations during a 13-year period which represents one of the largest studies of its type. The authors should be commended for undertaking this study as it adds important information to the literature.
They found that the incidence of anesthesia-related complications is low and decreased over the study period. In regard to general anesthesia, they found that 65% of the serious adverse events were related to a failed or difficult intubation. This is in contrast to the findings of Mhyre et al who did not identify any maternal deaths related to failed intubation or difficult intubation; however, they found 5 deaths attributed to hypoventilation or airway obstruction during emergence, extubation, or recovery.1 Although the timing of complications related to airway management differed between studies, both studies highlight the need for heightened vigilance for parturients undergoing general anesthesia.
In regard to neuraxial anesthesia, the most common adverse event (although not serious) was postdural puncture headache with an incidence of 1 in 521 neuraxial anesthetics. This incidence is noted to be lower than in the United States, where the incidence is traditionally quoted as around 1:100 to 1:150 neuraxial anesthetics.2 Again, it is hard to explain this difference though it could be related to study design or type of practice studied; academic in the US study where practitioner skills are more varied, versus private practice where practitioners may be more seasoned.
Comment by Lauren Sartor, MD & Yaakov Beilin, MD
1. Mhyre JM, Riesner MN, Polley LS, et al. A series of anesthesia-related maternal deaths in Michigan, 1985-2003. Anesthesiology. 2007;106:1096–1104.
2. D’Angelo R, Smiley RM, Riley ET, et al. Serious complications related to obstetric anesthesia: The Serious Complication Repository Project of the Society for Obstetric Anesthesia and Perinatology. Anesthesiology. 2014;120:1505–1512.