Spinal anaesthesia with a small volume of local anaesthetic for hip surgery in elderly patients

C. Rusan¹, I. Acalovschi², D. Lucaciu¹, S. Hopulele1, I. Hopulele¹
1) Clinica de Ortopedie şi Traumatologie. 2) Catedra ATI – UMF „Iuliu Haţieganu” Cluj-Napoca

Abstract

Background. The pharmacological sympatholysis produced by local anaesthetics after subarachnoid administration, is associated with haemodynamic changes. Elderly patients have a fragile cardiovascular system (with low functional reserves) and at the same time a rigid one (low compliance), so they tolerate with difficulty the hypotension induced by spinal anaesthesia. The severity of hypotension is dependent on the extension of the sympathetic block, directly influenced by the amount of the injected local anaesthetic.

The aim of this study was to identify the minimal quantity of local anaesthetic (0.5% isobare bupivacaine) which provides adequate anaesthesia with a minimal haemodynamic effect.

Material and methods. Spinal anaesthesia was performed in 80 patients aged 75 to 103 years scheduled for hip surgery. These patients were separated in four randomized groups of 20 patients each. All patients from each group received the same quantity of 0.5 % bupivacaine for spinal anesthesia: the first group 2.5 ml, the second group 2 ml, the third group 1.5 ml and the fourth group 1 ml. During anaesthesia, the systolic and diastolic blood pressure, pulse, respiratory frequency and SpO2 were monitored. The extension and duration of the sensitive and motor block and the haemodynamic variables were also evaluated. Statistical analysis was performed with ANOVA or chi square tests p < 0.05 was regarded as significant. Results were expressed as mean (SD).

Results. The haemodynamic profile and the sensitive block differed as follows: in group 1 (2.5ml) the patients were haemodynamically unstable; in group 4 (1 ml) the analgesia was insufficient; the patients from groups 2 and 3 had a satisfactory analgesia and those from group 3 (1.5ml) had also a better haemodynamic profile.

Conclusions. The use of small volume of local anaesthetic (bupivacaine) for spinal anaesthesia decreases the severity of intraanaesthetic hypotension, which is beneficial for elderly patients who tolerate the haemodynamic changes with difficulty.
The minimal volume of 0.5% bupivacaine necessary for spinal anaesthesia for small and moderate amplitude hip surgery is 1.5 ml (7.5 mg). With this dose, an optimal ratio analgesia/haemodynamic profile is achieved.

Key words: subarachnoidian anaesthesia, bupivacaine, hip surgery, elderly patients

Jurnalul Român de Anestezie Terapie intensivă 2003 Vol.10 Nr.1, 23-27

Anestezia subarahnoidiană cu volume mici de anestezic local pentru chirurgia şoldului la vârstnici