Our aim was to investigate motor activity of the healthy, relatively unprepared colon in the ambulatory state. Twenty-five age- and gender-matched adults had a six-sensor solid-state probe inserted into the proximal transverse colon without sedation. Subjects ambulated freely and ate standard meals. In 528 h of recording, we found a lower (P < 0.05) area under the curve during the night. Waking induced a threefold increase in motility, whereas meals induced a twofold increase. Women showed less activity (P < 0.05) in the transverse/descending colon than men. The transverse/descending colon showed more (P < 0.05) activity than the rectosigmoid colon. Seven patterns were recognized; predominantly, they were simultaneous, propagated, or periodic bursts of 3-cycles/min (cpm) waves. A specialized propagating pressure wave with a high amplitude (>105 mmHg) and a prolonged duration (>14 s) occurred in all subjects (mean 10/day), mostly after waking, after meals, or with defecation. A 3-cpm motor activity was seen in the rectosigmoid region predominantly at night. The colon exhibits a wide spectrum of pressure activity around the clock, with gender and regional differences and circadian rhythm. This comprehensive study provides qualitative and quantitative normative data for colonic manometry.

Patients with slow-transit constipation exhibited either normal or decreased pressure activity with manometric features suggestive of colonic neuropathy or myopathy as evidenced by absent HAPC or attenuated colonic responses to meals and waking. In refractory patients, colonic manometry may be useful in characterizing the underlying pathophysiology and in guiding therapy.

In the lying position, one-third showed dyssynergia and one-half could not expel artificial stool. Whereas when sitting with distended rectum, most showed normal defecation pattern and ability to expel stool. Thus, body position, sensation of stooling and stool characteristics may each influence defecation. Defecation is best evaluated in the sitting position with artificial stool.

BackgroundWe report a case of a patient with apparent resistance to local anesthetics. While similar cases of failure of regional anesthetics are often attributed to technical failure, the overall clinical presentation and history of this patient suggests a true resistance to local anesthetics.Case PresentationThis patient presented for elective cesarean section and the decision for regional anesthesia was made. While attempting to place an epidural, the patient failed to achieve adequate skin analgesia despite multiple attempts at local infiltration. When a spinal was ultimately placed, sensory or motor blockade was not obtained despite no evidence of technical problems with technique. Further questioning revealed multiple prior episodes of local anesthetic failure in this patient.ConclusionsWhile the failure rate of spinal anesthesia has been shown range from 4–13% and is often attributed to technical failure, elements of this particular case suggest a true resistance to local anesthetics.