Biomaterial Database

The epidural sieve and MBC (minimal blocking concentration): an hypothesis. 1976

J S Crawford

Certain painful stimuli-of which those associated with placental abruptio and impending rupture of a uterine scar are examples-can penetrate an apparently well-established lumbar epidural block. As a possible explantation of this anomaly, it is suggested that, when used in the concentrations currently employed, the local anaesthetic reaches nerve axons only slightly above the minimal blocking concentration (MBC) of the drug, and that a more powerful stimulus can provoke an impulse which may be conducted through the "blocked" segment of axon. The beneficial aspects of the "epidural sieve" should be welcomed and no attempt made to eliminate the phenomenon.

UI	MeSH Term	Description	Entries
D007743	Labor, Obstetric	The repetitive uterine contraction during childbirth which is associated with the progressive dilation of the uterine cervix (CERVIX UTERI). Successful labor results in the expulsion of the FETUS and PLACENTA. Obstetric labor can be spontaneous or induced (LABOR, INDUCED).	Obstetric Labor
D010146	Pain	An unpleasant sensation induced by noxious stimuli which are detected by NERVE ENDINGS of NOCICEPTIVE NEURONS.	Suffering, Physical,Ache,Pain, Burning,Pain, Crushing,Pain, Migratory,Pain, Radiating,Pain, Splitting,Aches,Burning Pain,Burning Pains,Crushing Pain,Crushing Pains,Migratory Pain,Migratory Pains,Pains, Burning,Pains, Crushing,Pains, Migratory,Pains, Radiating,Pains, Splitting,Physical Suffering,Physical Sufferings,Radiating Pain,Radiating Pains,Splitting Pain,Splitting Pains,Sufferings, Physical
D011247	Pregnancy	The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.	Gestation,Pregnancies
D005260	Female		Females
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000767	Anesthesia, Epidural	Procedure in which an anesthetic is injected into the epidural space.	Anesthesia, Extradural,Anesthesia, Peridural,Epidural Anesthesia,Anesthesias, Epidural,Anesthesias, Extradural,Anesthesias, Peridural,Epidural Anesthesias,Extradural Anesthesia,Extradural Anesthesias,Peridural Anesthesia,Peridural Anesthesias
D000773	Anesthesia, Obstetrical	A variety of anesthetic methods such as EPIDURAL ANESTHESIA used to control the pain of childbirth.	Anesthesia, Gynecological,Anesthesia, Obstetric,Gynecologic Anesthesia,Paracervical Block,Anesthesia, Gynecologic,Block, Paracervical,Blocks, Paracervical,Gynecological Anesthesia,Obstetric Anesthesia,Obstetrical Anesthesia,Paracervical Blocks
D000779	Anesthetics, Local	Drugs that block nerve conduction when applied locally to nerve tissue in appropriate concentrations. They act on any part of the nervous system and on every type of nerve fiber. In contact with a nerve trunk, these anesthetics can cause both sensory and motor paralysis in the innervated area. Their action is completely reversible. (From Gilman AG, et. al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed) Nearly all local anesthetics act by reducing the tendency of voltage-dependent sodium channels to activate.	Anesthetics, Conduction-Blocking,Conduction-Blocking Anesthetics,Local Anesthetic,Anesthetics, Topical,Anesthetic, Local,Anesthetics, Conduction Blocking,Conduction Blocking Anesthetics,Local Anesthetics,Topical Anesthetics
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor