Tom H Boyles1, Elizabeth Gatley, Sean Wasserman, Graeme Meintjes. 1. *Division of Infectious Diseases and HIV Medicine, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; †Clinical Infectious Diseases Research Initiative, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; and ‡Department of Medicine, Khayelitsha District Hospital, Cape Town, South Africa.
Abstract
BACKGROUND: Patients with HIV-associated cryptococcal meningitis (CM) commonly present with raised intracranial pressure (ICP). Aggressive management of raised ICP reduces mortality but requires manometers, which are unavailable in most resource-limited settings. The law of Poiseuille states that the rate of flow of liquid through a tube is directly proportional to the difference in pressure between each end, and it may be possible to indirectly determine ICP by measuring flow of CSF through a spinal needle rather than using a manometer. METHODS: A convenience sample of CM patients requiring lumbar puncture (LP) (with 22-G spinal needle) for ICP measurement and control were enrolled. ICP was first measured using a narrow bore manometer. After removing the manometer, the number of drops of CSF flowing from the spinal needle in 15 seconds was counted. RESULTS: Thirty-two patients had 89 LPs performed (range, 1-23). Fifty-four had high opening pressure with a CSF flow rate of 16-200 drops/min, and 35 had normal pressure with a CSF flow rate of 8-140 drops/min. Area under the fitted receiver operator character curve was 0.89. A flow rate cutoff to define high pressure of ≥40 drops/min correctly classified 75 of 89 LPs (accuracy 84%). CONCLUSIONS: It is technically feasible to indirectly estimate CSF pressure to an accuracy that is clinically useful by counting drops of CSF flowing from a spinal needle. The optimal cutoff value for defining high pressure using a standard 22-G spinal needle is ≥40 drops/min. These findings have the potential to improve CM management in resource-limited settings.
BACKGROUND:Patients with HIV-associated cryptococcal meningitis (CM) commonly present with raised intracranial pressure (ICP). Aggressive management of raised ICP reduces mortality but requires manometers, which are unavailable in most resource-limited settings. The law of Poiseuille states that the rate of flow of liquid through a tube is directly proportional to the difference in pressure between each end, and it may be possible to indirectly determine ICP by measuring flow of CSF through a spinal needle rather than using a manometer. METHODS: A convenience sample of CMpatients requiring lumbar puncture (LP) (with 22-G spinal needle) for ICP measurement and control were enrolled. ICP was first measured using a narrow bore manometer. After removing the manometer, the number of drops of CSF flowing from the spinal needle in 15 seconds was counted. RESULTS: Thirty-two patients had 89 LPs performed (range, 1-23). Fifty-four had high opening pressure with a CSF flow rate of 16-200 drops/min, and 35 had normal pressure with a CSF flow rate of 8-140 drops/min. Area under the fitted receiver operator character curve was 0.89. A flow rate cutoff to define high pressure of ≥40 drops/min correctly classified 75 of 89 LPs (accuracy 84%). CONCLUSIONS: It is technically feasible to indirectly estimate CSF pressure to an accuracy that is clinically useful by counting drops of CSF flowing from a spinal needle. The optimal cutoff value for defining high pressure using a standard 22-G spinal needle is ≥40 drops/min. These findings have the potential to improve CM management in resource-limited settings.
Authors: Síle F Molloy; Tom Chiller; Gregory S Greene; Jessica Burry; Nelesh P Govender; Cecilia Kanyama; Sayoki Mfinanga; Sokoine Lesikari; Yacouba N Mapoure; Charles Kouanfack; Victor Sini; Elvis Temfack; David R Boulware; Francoise Dromer; David W Denning; Jeremy Day; Neil R H Stone; Tihana Bicanic; Joseph N Jarvis; Olivier Lortholary; Thomas S Harrison; Shabbar Jaffar; Angela Loyse Journal: PLoS Negl Trop Dis Date: 2017-06-29
Authors: Nelesh P Govender; Graeme Meintjes; Phetho Mangena; Jeremy Nel; Samantha Potgieter; Denasha Reddy; Helena Rabie; Douglas Wilson; John Black; David Boulware; Tom Boyles; Tom Chiller; Halima Dawood; Sipho Dlamini; Thomas S Harrison; Prudence Ive; Joseph Jarvis; Alan Karstaedt; Matamela C Madua; Colin Menezes; Mahomed-Yunus S Moosa; Zaaheera Motlekar; Amir Shroufi; Sarah Lynn Stacey; Merika Tsitsi; Gilles van Cutsem; Ebrahim Variava; Michelle Venter; Rachel Wake Journal: South Afr J HIV Med Date: 2019-11-08 Impact factor: 2.744