Investigation Into Blood Pressure Monitoring Requirements During Intravenous Midazolam Sedation

Objectives: Intravenous midazolam sedation (IVMS) has become an invaluable tool in the dental armamentarium to aid the management of patients with anxiety. There remains concern amongst anaesthetists that dental practitioners are untrained to recognise or equipped to manage hyper- or hypotensive emergencies. Intra-procedural blood pressure (BP) monitoring is recommended, however isolated pre- and post-procedural measurements are often the only form of monitoring in a dental setting. The aim was to retrospectively investigate pre- and intra-procedural BP to assess risk and to provide guidance on monitoring protocols.

Methods: Sedation records of 90 sequential IVMS procedures undertaken by three Speciality Dentists were examined. Gender, age, ASA classification, medical history, midazolam dose, procedure and procedural time were recorded to allow data stratification during analysis. Pre-operative BP, and intra-operative BP at ten minute intervals were recorded. BP and pulse pressure measurements were analysed using Wilcoxon signed rank tests (P<0.05). The impact of elapsed time from midazolam delivery on intra-operative BP was tested using Friedman tests (P<0.05). Pearson's coefficients were generated to explore correlations with significant patient variables.

Results: 90 subjects comprised 56 females and 34 males and were predominantly ASA 1 with a mean age of 37yrs. Mean midazolam dose was 6.3±2.5mg. The repeat measures Wilcoxon tests revealed a significant reduction in BP following midazolam delivery (P<0.001, 76 negative ranks). The median BP post-midazolam delivery was 116/71 mmHg. Freidman tests demonstrated that the intra-procedural systolic pressure did not significantly alter as time elapsed (P=0.142) but significant variation in the diastolic pressure was observed (P=0.047). The median pulse pressure at discharge of 39.5mmHg was significantly lower than the pre-operative measurement 48.0mmHg (P<0.001).

Conclusion: Findings suggest that following the anxiolytic actions of midazolam, patients remained largely normotensive throughout the procedure duration. Variability observed in diastolic pressure tending to hypotension suggests that intra-procedural BP monitoring is necessary.