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Electrical and mechanical activity on longitudinal and circular layers of the human sigmoid colon were simultaneously studied. Recordings were obtained from two electrode sites spaced 3 cm apart in a piece of colon which had been resected surgically and perfused in an organ bath. Spontaneous electrical activity of the colon showed slow waves and spikes. Slow waves were present for only 24.5% and 12% of the recording time on the longitudinal and circular layers, respectively, and they appeared as localized activity which was irregular in amplitude and varying in frequency. Electrical coupling between the two muscle layers was rarely seen and slow waves were not associated with pressure changes. Spiking activity were recorded as short and long spike bursts on both muscle layers. Short spike bursts were localized activity superimposed on slow waves. The associated mechanical activity, which consisted of single weak pressure changes or prolonged contractions with summation, was determined by slow wave frequency. Long spike bursts were seen at irregular intervals and were either propagated or not propagated activity associated with electrical oscillations ranging from 24 to 46 cpm. Mechanical activity consisted of sustained tonic contractions propagated or not propagated in the same way as the electrical pattern. Coordinated electrical activity of the two muscle layers seldom occurred when spontaneous activity was being recorded. Electrical activity on both muscle layers was very sensitive to stretching and could be initiated or modulated by pharmacological agents. In particular, our findings showed that stimulation induced coordinated spiking activity on the two muscle layers and caused mechanical activity, propagated orally or aborally, which consisted of long lasting, high amplitude contractions.(ABSTRACT TRUNCATED AT 250 WORDS)

Background Many surgeons routinely place intraperitoneal drains after elective colorectal surgery. However, enhanced recovery after surgery guidelines recommend against their routine use owing to a lack of clear clinical benefit. This study aimed to describe international variation in intraperitoneal drain placement and the safety of this practice. Methods COMPASS (COMPlicAted intra-abdominal collectionS after colorectal Surgery) was a prospective, international, cohort study which enrolled consecutive adults undergoing elective colorectal surgery (February to March 2020). The primary outcome was the rate of intraperitoneal drain placement. Secondary outcomes included: rate and time to diagnosis of postoperative intraperitoneal collections; rate of surgical site infections (SSIs); time to discharge; and 30-day major postoperative complications (Clavien–Dindo grade at least III). After propensity score matching, multivariable logistic regression and Cox proportional hazards regression were used to estimate the independent association of the secondary outcomes with drain placement. Results Overall, 1805 patients from 22 countries were included (798 women, 44.2 per cent; median age 67.0 years). The drain insertion rate was 51.9 per cent (937 patients). After matching, drains were not associated with reduced rates (odds ratio (OR) 1.33, 95 per cent c.i. 0.79 to 2.23; P = 0.287) or earlier detection (hazard ratio (HR) 0.87, 0.33 to 2.31; P = 0.780) of collections. Although not associated with worse major postoperative complications (OR 1.09, 0.68 to 1.75; P = 0.709), drains were associated with delayed hospital discharge (HR 0.58, 0.52 to 0.66; P < 0.001) and an increased risk of SSIs (OR 2.47, 1.50 to 4.05; P < 0.001). Conclusion Intraperitoneal drain placement after elective colorectal surgery is not associated with earlier detection of postoperative collections, but prolongs hospital stay and increases SSI risk.

To explain the origin of the electrical signals obtained from the abdominal cutaneous surface (electrosplanchnogram, ESG), the ESG was recorded in 6 patients with carcinoma of the right colon without obstruction before and after right hemicolectomy. The analysis of colonic electrical activity was performed by means of spectral analysis that utilized fast Fourier transform method. Since the colonic electrical signal is highly complex and it may contain several frequencies concurrently the spectral frequency components were subdivided in ranges and the dominant frequency and power were calculated for each range before and after surgery. The pattern obtained from power profile, expressed as differences in power percentages before and after surgery, demonstrated that there were significant differences in power data from right hemicolectomized patients compared to cholecystectomized ones (p = 0.00001 and p = 0.001 in 2.5-3.5 and 3.6-7.5 cpm range, respectively). In particular, hemicolectomized patients showed a slight increase of power percentage in the 2.6-3.5 cpm range and a clear reduction in the 3.6-7.5 cpm range. These data suggest that there are several components of colonic origin in the cutaneous ESG signal which, in the right colon, are identifiable in the 3.6-7.5 cpm range.