Hi Francois, For pain measurements it is not uncommon to analyze data with a upper limit of quantitation. You can follow the literature on BQL, only reversing from a lower limit to an upper limIt. In my experience just deleting censored data works fine, certainly as a first attempt, as long as censoring stays below ~1/3 of total data.
Best regards, Jeroen J. Elassaiss-Schaap Scientist PK/PD MSD PO Box 20, 5340 BH Oss, Netherlands Phone: + 31 412 66 9320 Fax: + 31 412 66 2506 e-mail: [email protected] ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Francois Gaudreault Sent: Monday, December 19, 2011 21:40 To: [email protected] Subject: [NMusers] Truncated Emax Dear NM users I am currently developing a PK PD model for local anesthetics using a sequential approach with ADVAN6. The PD model is a sigmoid Emax with an effect compartment (Ce). The intensity and duration of nerve blockade are monitored throughout the perioperative period in patients using a quantitative pharmacodynamic endpoint, i.e, the current perception threshold (CPT) REF: Can. J. Anesth, 57 (S1) 2010). Briefly, CPT is evaluated before and after the administration of the local anesthectic. Data are normalized by baseline using the following equation : (observed-baseline) / (max-baseline) *100 (%) Here is the problem. The device only goes to a maximum of 10 mA. In some patients, the real Emax is much higher. Any ideas on how handle a truncated Emax ? Thanks in advance -- François Gaudreault, Ph.D. Candidate Pharmacométrie / Pharmacometrics Charger de cours / Lecturer Faculté de pharmacie / Faculty of Pharmacy Université de Montréal Notice: This e-mail message, together with any attachments, contains information of Merck & Co., Inc. (One Merck Drive, Whitehouse Station, New Jersey, USA 08889), and/or its affiliates Direct contact information for affiliates is available at http://www.merck.com/contact/contacts.html) that may be confidential, proprietary copyrighted and/or legally privileged. It is intended solely for the use of the individual or entity named on this message. If you are not the intended recipient, and have received this message in error, please notify us immediately by reply e-mail and then delete it from your system.
