Study appraisals for quality (randomization, blinding, and outcome assessment) and data extraction were performed by two investigators independently. Fifteen randomized trials of interventions to reduce adverse events met criteria for inclusion, and four studies of the diagnostic test characteristics of CSF analysis met criteria and were included.
Meta-analysis with a random effects model of five studies (total of 587 patients) comparing atraumatic needles with standard needles yielded a nonsignificant decrease in the odds of headache with an atraumatic needle (absolute risk reduction [ARR], 12.3%; 95% confidence interval [CI], –1.72% to 26.2%). A single study of reinsertion of the stylet before needle removal (600 patients) showed a decreased risk of headache (ARR, 11.3%; 95% CI, 6.50%-16.2%). Meta-analysis of four studies (717 patients) revealed a nonsignificant decrease in headache in patients mobilized after LP (ARR 2.9%; 95% CI, –3.4 to 9.3%).
Data from the diagnostic test studies yielded the following likelihood ratios for diagnosing bacterial meningitis: A CSF–blood glucose ratio of 0.4 or less with a likelihood ratio of 18 (95% CI, 12-27); CSF white blood cell count of 500/µL or higher with a likelihood ratio of 15 (95% CI, 10-22); and CSF lactate level of >31.53 mg/dL with a likelihood ration of 21 (95% CI, 14-32) in accurately diagnosed bacterial meningitis.
These data support the reinsertion of the stylet before needle removal to reduce the risk of headache after lumbar puncture and that patients do not require bed rest after diagnostic lumbar puncture. Biochemical analyses, including CSF-blood glucose ratio, CSF leukocyte count and lactate level are useful in diagnosing bacterial meningitis.
This Rational Clinical Examination systematic review and meta-analysis provides a nice review of the available data on optimizing diagnostic lumbar puncture technique to reduce adverse events. It is somewhat remarkable so little has changed in our knowledge about this long-standing diagnostic procedure. Post-lumbar puncture headaches remain a challenge that may affect patient satisfaction as well as hospital (or observation unit) course particularly for patients who do not have evidence of bacterial meningitis once the analysis is complete.
This review seems to provide some useful answers for physicians performing lumbar puncture, who should consider selecting a small gauge needle and reinserting the stylet prior to removal. Future studies of other maneuvers to reduce post-procedure adverse events should be considered for the question of atraumatic needles, which may be technically more difficult to use. The review confirms and helps quantify the utility of CSF biochemical analysis in the diagnosis of bacterial meningitis.
Who’s Performing Procedures?
Wigton RS, Alguire P. The declining number and variety of procedures done by general internists: a resurvey of members of the American College of Physicians. Ann Intern Med. 2007 Mar 6;146(5):355-360. Comment in Ann Intern Med. 2007 Mar 6; 146(5):392-393.
Prior surveys of physicians documented that general internists performed a variety and significant number of procedures in their practice. Much has changed since those prior assessments, including physician training, practice settings, availability of subspecialists, and regulatory requirements that have altered physician’s practice with regard to procedures. This study sought to reassess the volume and variety of procedures performed by general internists compared with the prior survey of 1986. The final sample included 990 completed surveys from general internists from 1,389 returned questionnaires for a successful completion rate of 39.6%.
The median number of different procedures performed in practice decreased from 16 in 1986 to seven in 2004. Internists who practiced in smaller hospitals or smaller towns reported performing almost twice as many procedures as physicians in the largest hospitals and cities. Hours spent in the care of hospitalized patients were also associated with an increased number of different procedures—in particular mechanical ventilation, central venous catheter placement, and thoracentesis. For all but one of the 34 procedures common to both surveys, fewer general internists performed them in 2004 compared with 1986. Remarkably, for 22 of the 34 procedures, a greater than 50% reduction in the proportion of respondents who performed the procedure was noted.