Definitions in obstetric anaesthesia: how should we measure anaesthetic workload and what is 'epidural rate'?

Long-term capacity planning for obstetric surgical suites using quantile linear regression

Obstetric surgical suites differ from most inpatient surgical suites, serving one specialty, and often small. We evaluated long-term capacity planning for these operating rooms. The retrospective cohort study included all caesarean births in three operating rooms over 28 years, 1994 through 2021, plus all other obstetric procedures over the latter 19 years. We calculated the obstetric anaesthesia activity index, 0.5 × neuraxial labour analgesia placement + 1.0 × caesarean births. Annual caesarean births from one year to the next had a Pearson linear correlation coefficient of 0.993. Therefore, linear regression can be used for long-term capacity planning. However, the difference between 0.9 and 0.1 quantiles in weekly caseloads was greater than tenfold larger than the annual rate of growth in births per week. Therefore, clinicians likely would be unable to distinguish, by experience, between growth versus being busy due to variability, suggesting value of the modelling. Over 19 years, the fraction of the obstetric workload from caesarean births was unchanging, Pearson correlation coefficient of 0.04. Therefore, use of the obstetric anaesthesia activity index to judge changes in workload was appropriate. The annual total for the index increased linearly, Pearson correlation coefficient of 0.98, supporting validity of the finding that long-term capacity can be planned with linear regression. The difference between 0.9 and 0.1 quantiles in weekly totals of the index exceeded annual rate of growth, supporting validity of the finding that variability week to week is very large relative to growth. These results help decision-makers ensure that operating rooms and staff meet referring hospitals' needs.

Obstetric Anesthesia Procedure-Based Workload and Facility Utilization of Society of Obstetric Anesthesia and Perinatology Centers of Excellence Designated Institutions

BACKGROUND

Optimal workload and staffing for obstetric anesthesia services have yet to be determined. We surveyed Society of Obstetric Anesthesia and Perinatology (SOAP) Centers of Excellence (COE) for Obstetric Anesthesia Care institutions to evaluate procedure-based obstetric anesthesia workload and facility use.

METHODS

After institutional review board (IRB) exemption, an online survey instrument (REDCap) was sent by email (1 initial and 2 reminders) to all SOAP COEs. Survey data included the number of deliveries, cesarean delivery rate, neuraxial labor analgesia rate, the number of labor and operating rooms, and the number of in-house and backup obstetric anesthesia providers. Obstetric anesthesia activity was estimated using a time-based workload ratio per provider (Stanford Work Index, 1.0 = clinically working every minute of every hour on duty) during weekday, weeknight, and weekend shifts. We compared workload between academic and nonacademic centers and correlated operating and labor rooms with cesarean and vaginal delivery volume.

RESULTS

Fifty-one of 53 surveys were returned (96% response rate). Data from 33 academic and 14 nonacademic US institutions were analyzed. For academic centers, median Stanford Work Index for all staff (included trainees and Certified Registered Nurse Anesthetists) was 0.20 (weekday) and 0.19 (weeknight and weekends); nonacademic centers were 0.33 (weekday, P < .001 versus academic), 0.23 (weeknight, P = .009 versus academic), and 0.23 (weekends, P = .03 versus academic practices). Attending-only Stanford Work Indices were similar between academic and nonacademic centers. Total number of rooms on the obstetric suite (operating, labor, or triage room) was strongly correlated with delivery volume ( R2 = 0.55).

CONCLUSIONS

The results outline staffing procedure-based workload ratios and facility utilization at SOAP COEs in the United States. These data can be used by other institutions that provide obstetric anesthesia services to guide their obstetric anesthesia staffing. The importance of considering the workload associated with different shifts and between academic and nonacademic centers is also highlighted. The results show that approximately one-third of an obstetric anesthesiologist's workload is spent on performing procedures. We did not, however, measure the other tasks anesthesiologists practice as peripartum physicians (eg, managing critically ill parturients, doing pre- and postprocedural evaluations, or performing emergent and unexpected procedures), and future studies are required to determine the time required to perform these tasks. Studies to determine the optimal staffing models to handle workload fluctuations and improve outcomes are also required.

An audit of the effect of case selection on compliance with a 30-minute audit standard for decision-to-delivery interval at category 1 caesarean section

BACKGROUND

Our hospital has an audit standard that ≥90% of women having category 1 (emergency) caesarean section should have a decision-to-delivery interval (DDI) ≤30 min. This audit aimed to identify potential influences of case selection on compliance.

METHODS

A prospective audit of category 1 caesarean section recorded urgency at time of decision for surgery and any urgency changes, as well as whether caesarean section followed failed operative vaginal delivery in the operating theatre.

RESULTS

Among 405 women, 158 women had failed operative vaginal delivery in the operating theatre followed by caesarean section, 247 had the delivery decision made in the labour room, 43 had a change in urgency. Depending on case inclusion, the proportion of women with DDI room, and 43 >30 min ranged between 8.3% (30/362; no urgency change, failed operative vaginal delivery included) and 21.9% (54/247; change in urgency, failed operative vaginal delivery excluded). The proportion of women with a DDI >30 min was 18.5% (42/227) if the decision for category 1 caesarean section was made in the labour delivery room (excluding cases of failed operative vaginal delivery).

CONCLUSIONS

Compliance with an audit standard for (DDI) at category 1 caesarean section is markedly influenced by the inclusion criteria. For comparability with other publications, it is suggested urgency should be reported as that applied at the point of decision for caesarean section, however, category 1 caesarean section cases following failed operative vaginal delivery in the operating theatre should be identified and reported separately.

A first step in determining appropriate amounts of obstetric anesthesia work

Ginosar, et al. describe a new performance indicator, the Obstetric Anesthesia Activity Index, to represent the current amount of obstetric anesthesia work done daily at each of 25 Israeli hospitals. The authors claim, correctly, that this index is a closer reflection of the anesthetic workload than simply looking at the number of deliveries at each hospital. However, the Obstetric Anesthesia Activity Index could easily be refined to reflect more closely the actual obstetric anesthesia workload by using the average cesarean delivery time for each hospital rather than one value for all hospitals. Although the authors state that they developed the Obstetric Anesthesia Activity Index out of concern for inadequate obstetric anesthesia manpower in Israel, they have not compared the Obstetric Anesthesia Activity Index with the size of the patient population or any measure of patient satisfaction or patient safety. In its current form, the Obstetric Anesthesia Activity Index describes the current work situation but does not evaluate the extent of the unmet need for additional anesthesia providers. Despite these shortcomings, the Obstetric Anesthesia Activity Index is an important first step in developing a tool to assess unmet obstetric anesthesia needs.

An analysis of the need for anesthetic interventions with differing concentrations of labor epidural bupivacaine: an observational study

BACKGROUND

Labor epidural analgesia techniques using lower concentrations of bupivacaine are designed to maintain pain control with fewer side effects such as hypotension and motor block. However, the increase in sensation may allow breakthrough pain resulting in the need for additional interventions. We examined the number of interventions, both for analgesia and for treatment of side effects, required when using three concentrations of bupivacaine.

METHODS

Retrospective observational investigation examining 4493 women who received epidural analgesia during two periods. In the first period, higher concentrations of bupivacaine were used (0.125% and 0.0625%, both with fentanyl 2 microg/mL). In the second period, a very low concentration was used (0.04% plus fentanyl 1.7 microg/mL and epinephrine 1.7 microg/mL). Outcomes were compared using univariate tests, and multivariate Poisson regression was used to identify independent factors influencing interventions.

RESULTS

The frequencies of interventions were similar for women receiving bupivacaine concentrations of 0.04% (1.4+/-2.0) and 0.125% (1.5+/-2.0), while women receiving the 0.0625% solution required more interventions (1.8+/-2.3; P<0.001). Women who received 0.04% or 0.0625% bupivacaine required more treatment of breakthrough pain (P<0.002), while those receiving 0.125% bupivacaine required more treatment for hypotension and motor block (P<0.05). Multivariate Poisson regression showed that duration of treatment, maternal age and body mass index were independent factors for the number of interventions.

CONCLUSIONS

Neither the total interventions nor intervention rate per hour varied significantly with the concentrations of bupivacaine used in this study. Lower concentrations produced fewer side effects including hypotension, while the higher concentration resulted in less breakthrough pain.

[Regionalization of obstetric services and anaesthetic workload in a tertiary level perinatal unit]

OBJECTIVE

Evaluation of anaesthetic workload associated with care of high-risk pregnant women (i.e. patients transferred to a referral perinatal center).

STUDY DESIGN

A case-control prospective study.

METHODS

During a three-month period, 63 women with in-utero transfer and their control counterparts (63 normal pregnancies) were prospectively followed until discharge.

RESULTS

At inclusion, high-risk patients (n = 63) were more frequently scored ASA 2 or more (21 vs 0%, p < 0.05). ASA score had increased at delivery in 8% of high-risk women and in none of controls. ICU admission (4 vs none), Caesarean delivery (57 vs 11%), preanaesthetic visit at night (41 vs 0%) and general anaesthesia (27 % versus none) were all more frequent in high-risk parturients (p < 0.05).

CONCLUSION

Comparison of the workload associated with high-risk patients and normal pregnant women confirms the need for increased anaesthetic staffing in referral perinatal centers and provides a basis for better understanding the distribution of anaesthetic requirements in each perinatal network.

Trends in obstetric anaesthesia and analgesia over a ten year period in the University Malaya Medical Centre, Kuala Lumpur

Available data for obstetric care in the University Malaya Medical Centre, Kuala Lumpur from 1987 to 1999 were reviewed. Despite incomplete data, we were able to determine fairly well the practice of obstetric anaesthesia and analgesia in the unit, and the changes over the years. There was a decline in the use of general anaesthesia for both elective and emergency caesarean sections from 41.3% and 69.4% respectively in 1995 to 21.6% and 26.9% respectively in 1999. By 1999, regional anaesthesia had become the most common method of anaesthesia administered in both elective (14.3% epidural and 63.5% spinal) and emergency (30.2% epidural and 42.6% spinal) caesarean sections. The percentage of patients delivering vaginally who received epidural analgesia appeared to have stabilised at about 8 to 9% in the last few years, with a gradual decline in the total instrumental delivery rate from a high of about 12% to the pre-epidural rate of 7%.

Obstetric anaesthetists' workload

The current recommendation of one consultant session per 500 deliveries with full sessional cover for units over 3000 deliveries is arbitrary and is not based on workload. The Audit Commission has questioned the wide variability of anaesthetic staffing on labour wards. The aim of this study was to investigate whether there is a relationship between current workload and obstetric anaesthetic staffing in five maternity units. In 1998, a 2-week diary of workload in the participating obstetric units was assessed in terms of staffing and clinical and nonclinical activities. The busiest time was 08:00 to 12:30. The working patterns between consultants and trainees varied considerably. Time spent on nonclinical activity by consultants averaged 51%. Any calculation of consultant sessions will need to take into account nonclinical activities. Other factors requiring consideration are the number of high-risk cases, as well as the number and experience of trainees.

National obstetric anaesthetic practice in the UK 1997/1998

In the United Kingdom, the Royal College of Obstetricians and Gynaecologists requires maternity units recognised for training to complete annual statistical returns. Analysis of these data revealed that anaesthetists were directly involved in more than 251 000 procedures in the peripartum period in 1997/1998. There had been an increase in the number of women delivered by Caesarean section (18. 5% of all deliveries) compared with previous reports. The proportion of Caesarean sections performed under regional anaesthesia had increased for both elective and emergency Caesarean section deliveries (85.5% and 70.2%, respectively). For pain relief in labour, there had been neither an increase nor a decrease in the uptake of regional analgesia (23.6%). There were limited training opportunities for anaesthetists in general anaesthesia for Caesarean section and for obstetricians in vaginal breech delivery. The known admissions to intensive care units equated to over 100 women per month in the United Kingdom requiring intensive care as a result of childbirth.

Urgency of caesarean section: a new classification

A new classification for caesarean section was developed in a two-part study conducted at six hospitals. Initially, 90 anaesthetists and obstetricians graded ten clinical scenarios according to five different classification methods--visual analogue scale; suitable anaesthetic technique; maximum time to delivery; clinical definitions; and a 1-5 rating scale. Clinical definitions was the most consistent and useful, and this method was then applied prospectively to 407 caesarean sections at the same six hospitals. There was close agreement (86%) between anaesthetists and obstetricians for the five-point scale (weighted kappa 0.89), increasing to 90% if two categories were combined (weighted kappa 0.91). We suggest that the resultant four-grade classification system--(i) immediate threat to life of woman or fetus; (ii) maternal or fetal compromise which is not immediately life-threatening; (iii) needing early delivery but no maternal or fetal compromise; (iv) at a time to suit the patient and maternity team--should be adopted by multidisciplinary groups with an interest in maternity data collection.