Retrospective audit of the investigation of patients with suspected acute subarachnoid haemorrhage

INTRODUCTION

Recommended investigational care (RIC) of emergency department (ED) patients with suspected subarachnoid haemorrhage comprises lumbar puncture (LP) to detect xanthochromia if the preceding CT scan is negative.

METHODS

Retrospective audit of the investigational care of 100 consecutive ED patients presenting with possible subarachnoid haemorrhage.

RESULTS

Of the 100 patients, 91 had negative CT, and 36 (39.6%) of these patients had an LP performed to detect xanthochromia (i.e. RIC). Fifty-five of 91 (60.4%) patients did not receive RIC. Of the 55 patients who did not receive RIC, 25 (45.5%) had a documented senior clinical decision not to perform an LP; 15 (27.3%) had no documented reason; five (9.1%) refused consent; two (3.6%) had an LP but no xanthochromia requested, one patient did not have an LP because of technical issues, six patients underwent CT angiography (CTA), and one patient underwent magnetic resonance angiography (MRA), in the absence of a LP, following a negative CT. Two patients underwent CTA following a negative xanthochromia result. Patients admitted to the emergency extended care unit had 6.85 times the odds of receiving RIC (95% CI 2.20-21.4).

CONCLUSIONS

Fifty-five (55) of 91 (60%) ED patients did not receive RIC. Fifteen of the 55 did not have any documented justification for not performing an LP with xanthochromia testing. Admission to an emergency extended care unit was a predictor of receiving RIC. Inappropriate use of CTA and MRA was identified. These findings have important implications for patient safety. Multifaceted strategies are required to close this evidence-practice gap.

Bacterial interference with L-forms

During the course of studying the effect of normal nasal flora on the growth of L-forms, a clear zone of inhibition was observed around colonies of many coagulase-negative staphylococci. Subsequent investigation demonstrated that Staphylococcus aureus and some S. albus strains produce a substance which is capable of markedly inhibiting the growth of stable staphylococcal and streptococcal L-forms. This interfering substance is separable from the staphylococcal organism and is diffusible through 1.5% agar, but not through a dialysis membrane. It is heat-stable.