Obstetric anesthesia practice in Canada

Ultrasound assessment of gastric contents prior to placental delivery: A prospective multicentre cohort study

BACKGROUND

There is ongoing debate regarding the optimal general anaesthetic technique for manual removal of the placenta after vaginal delivery. Using ultrasound examination of the gastric antrum, this study aimed to assess the change in gastric contents during vaginal delivery and to determine the prevalence of stomach at risk for pulmonary aspiration in the immediate postpartum period before placental delivery.

METHODS

In this prospective multicentre cohort study, antral ultrasonography was performed at full cervical dilatation within the thirty minutes preceding the beginning of expulsive efforts and after vaginal birth, before placental delivery. High-risk gastric content was defined as the visualisation of any solid content in the antrum or antral cross-sectional area in the semi-recumbent position (SR-CSA) > 608 mm².

RESULTS

Twenty-six women were included and analysed. There was a significant decrease in both the proportion of patients with solid gastric content and the SR-CSA between the two-ultrasound examinations. Twenty-one patients (80.8%) exhibited a decrease in the SR-CSA during vaginal delivery. The prevalence of stomach at risk for pulmonary aspiration was significantly lower after vaginal delivery than before vaginal delivery (23.1% vs. 57.7%, P = 0.0004).

CONCLUSION

Our results suggest that gastric emptying is at least partially preserved during vaginal birth. Nevertheless, almost a quarter of women did have high-risk gastric content in the immediate postpartum period. Point-of-care antral ultrasonography may be of interest for the fast assessment of the gastric content status when a general anaesthesia is required for manual removal of retained placenta.

Epidural test dose in obstetric patients: should we still use it?

PURPOSE OF REVIEW

As the application of a test dose after epidural catheter insertion in obstetrics has recurrently been associated with serious adverse events affecting both maternal and foetal outcomes, the question whether to test or not remains a controversial issue.

RECENT FINDINGS

Present guidelines do not provide clear recommendations in this regard and several recent surveys indicate a heterogeneity in clinical routine.

SUMMARY

Physiological alterations during pregnancy and labour restrict the use and also the validity of traditional test agents. Epinephrine is not appropriate to detect a vascular insertion in labour and the application of a local anaesthetic test dose may lead to dose-dependent fatal consequences should the catheter be intrathecal, due to an increased sensitivity in parturients. Given the current practice of opioid-amended-low-concentration epidurals, the waiving of a test dose results at worst in a failed epidural, a stark contrast to the potentially severe to fatal complications of a 'traditional' test dose. Hence, an originally preventive measure providing potentially more harm than the consequences of the situation aimed to prevent, should not be recommended. A simple fractionated administration of the initial analgesic dose seems reasonable though.

Ultrasound assessment of gastric content in the immediate postpartum period: a prospective observational descriptive study

INTRODUCTION

Pulmonary aspiration of gastric contents in pregnant women undergoing general anesthesia or sedation/analgesia in the peripartum period is a feared complication in obstetric anesthesia. We assessed the changes in antral cross-sectional area (CSA) with ultrasonography in laboring women and in the immediate postpartum period.

PATIENTS AND METHODS

In an observational study in a university-affiliated maternity, gastric ultrasonography examinations were performed in non-consecutive laboring women, after epidural analgesia insertion and after childbirth. Assessment of antral CSA, difficulty of performance on a numerical scale, and factors that could influence gastric content were noted. A cut-off value of 381 mm² was taken for the diagnosis of empty stomach.

RESULTS

One hundred women were enrolled in the study. Median antral CSA was 469 mm² [25th-75th] [324-591] after epidural insertion and 427 mm² [316-574] after delivery. Antral CSA was ≥ 381 mm² in 59 of 90 women (65%) after epidural insertion vs. 48 of 100 women (48%) after delivery (P = 0.59). Median variation of antral CSA between two measurements was 36 mm² [-42 to 114]. Gastric ultrasonography was significantly more difficult to perform during labor than immediately post-delivery (median difficulty score 5 [2-7] vs. 2 [1-4], P < 0.0001). No risk factors (pain, anxiety, diabetes, smoking) were significantly associated with the occurrence of full stomach post-delivery.

CONCLUSION

This study demonstrated that 48% of parturients in the immediate postpartum period presented an antral CSA ≥ 381 mm² , cut-off being accepted for diagnosis of empty stomach and emphasizes the need for re-assessing before any general anesthetic procedure.

Survey of chronic pain practice by anesthesiologists in Canada

PURPOSE

To describe the pattern of chronic pain practice (CPP) among anesthesiologists in Canada.

METHODS

Following hospital Ethics Committee approval, a detailed postal questionnaire was sent to all active members of the Canadian Anesthesiologists' Society. A second mailing was conducted two months later.

RESULTS

The overall response rate was 53%. While 38% of responding anesthesiologists were involved in CPP, in the majority of cases, this accounted for less than 20% of their clinical time. Thirty percent of those involved in CPP had previous training in pain management. The types of CPP included nerve blocks (84%) and pharmacological treatment (60%) in non-cancer pain (85%) and cancer pain (50%) patients. Ten percent and 28% of anesthesiologists were involved in research and teaching respectively while 26% were affiliated with a multidisciplinary clinic. The healthcare professions that anesthesiologists had access to or were directly working with in their practice were as follows: acupuncture (18%), nursing (36%), psychology (28%), psychiatry (35%) and physiotherapy (58%). Epidural steroid injection was the most commonly practiced intervention (82%). This was followed by trigger point injection (70%), stellate ganglion block (61%), occipital nerve block (60%) and lumbar sympathetic block (50%). Practice of interventional procedures was highly diverse. Seventy percent of anesthesiologists prescribed opioids as part of their CPP. However, half of them never incorporated an opioid agreement with patients. Opioids were most commonly used in the sustained release form.

CONCLUSION

Approximately one-third of anesthesiologists surveyed incorporate chronic pain in their practice and their pattern of practice is widely diversified.

Consent for anaesthesia

Current professional guidelines concerning information and consent for anaesthesia are a fair representation of English law. However, they reject the need for specific, written consent for anaesthesia, a position which is in accordance with other Western jurisdictions. This is understandable, as there would be a number of problems inherent in such an approach: the consent process would be unnecessarily labour and time intensive, the generic nature of the information to be disclosed would not allow for operator-dependent variables, and many of the disclosable risks continue to be of uncertain incidence. Moreover, written consent is not needed in order to defend cases of assault by anaesthetists. However, for the very reason that there are a large number of risks associated with anaesthesia (risks that are unknown to the majority of surgeons), together with the possibility of the courts moving towards a reasonable patient standard of information disclosure (as a result of the introduction of human rights legislation into English law), it is our view that the Association of Anaesthetists of Great Britain and Ireland should change their guidelines and advise anaesthetists to obtain separate, written affirmation from patients that certain risks and consequences of anaesthesia have been explained to them. In addition, a standardised consent form for anaesthesia may prove invaluable in retrospectively defending a claim of negligence founded around information disclosure, by recording exactly the risks and consequences of interventions discussed by the anaesthetist and the patient.