Pathophysiological and clinical aspects of the CO2 pneumoperitoneum (CO2-PP)

Experimental studies demonstrated a severe cardiac load of the CO₂ pneumoperitoneum caused by an accelerated after- and a decreased preload. Patients displaying cardiovascular risks are therefore often rejected from laparoscopic surgery. Hence, the pathophysiological changes and the intraoperative risk of the CO₂ pneumoperitoneum in high-risk cardiopulmonary patients (NYHA II–III, n= 15) undergoing laparoscopic cholecystectomy are described. The changes in cardiac after- and preload seem to be due to the elevated intraabdominal pressure rather than transperitoneally resorbed CO₂ and are reversible by desufflation. In one patient conversion to open operation had to be performed because of a severe drop in cardiac output and right ventricle ejection fraction. Mixed oxygen saturation was predicting intraoperative worsening in this case. The described pathophysiological changes may seem to be well tolerated even in high-risk cardiac patients. Monitoring of hemodynamics should include an arterial catheter line and blood gas analyses. Pharmacologic interventions or pressureless laparoscopic procedures might not be necessary as long as laparoscopic cholecystectomy is performed. Received: 13 December 1996/Accepted: 8 January 1997     

An observer blind trial of co-amoxiclav versus cefuroxime plus metronidazole in the prevention of postoperative wound infection after general surgery

A consecutive series of 509 patients undergoing abdominal surgery were entered into a randomized, observer and patient blind, controlled, prospective, study to evaluate the efficiency of co-amoxiclav (‘Augmentin’, SmithKline Beecham, UK) compared with cefuroxime (‘Zinacef’ Glaxo, UK) plus metronidazole (Flagyl, M&B, UK) for the prevention of postoperative wound infections. One or three doses of antibiotics were given depending on the type of surgery and operative factors. Co-amoxiclav was given to 230 patients with a total wound infection rate of 5·6% and cefuroxime plus metronidazole were given to 225 patients with a total wound infection rate of 3%. The difference between infection rates was not significant. Both groups were comparable in terms of demographic details, type and duration of surgery, risk factors associated with surgical procedures and postoperative management. Although not statistically significant, a difference in the wound infection rate for those patients undergoing colorectal surgery was seen: for the co-amoxiclav group and for the cefuroxime/ metronidazole group. The estimated cost to our hospital (October 1993) of one dose of co-amoxiclav was less that half the cost of cefuroxime and metronidazole. This study demonstrates that co-amoxiclav is an effective prophylactic antibiotic for abdominal surgery.     

Isoflurane for removal of chest drains after cardiac surgery

Thirty-five patients who had undergone uncomplicated cardiac surgery were randomly allocated to receive either Entonox or isoflurane 0.25% in Entonox as inhalational analgesia for the removal of their two chest drains. The gases were presented premixed in high-pressure cylinders and were self-administered by means of a demand valve. The removal of the second drain was more painful than the first but that pain was better controlled by isoflurane 0.25% in Entonox than by Entonox alone.     

A comparative analysis of radiological and surgical placement of central venous catheters

Purpose To compare the differences in practice and outcome of all radiologically and surgically placed central venous catheters retrospectively over a 2-year period simultaneously, at a single institution. Methods A total of 253 Hickman catheters were inserted in 209 patients; 120 were placed radiologically in 102 patients and 133 were placed surgically in 107 patients. The indication was chemotherapy in 76% of radiological and in 47% of surgical cases; the remainder were for total parenteral nutrition and venous access. Results There were 6 (4.5%) primary surgical failures and a further 17 (13%) surgical cases requiring multiple placement attempts. Pneumothorax occurred once (0.8%) surgically and four times (3.3%) radiologically. There were no radiological primary misplacements but there were five (3.7%) surgical ones. Catheter or central vein thrombosis occurred in four (3.3%) radiological and five (3.7%) surgical cases. The rate of infection per 1000 catheter-days was 1.9 in radiologically placed catheters and 4.0 in surgically placed ones (p<0.001). Average catheter life-span was similar for the two placement methods (100±23 days). Conclusion Radiological placement is consistently more reliable than surgical placement. There are fewer placement complications and fewer catheter infections overall.     

Linking perceptions of the community to behavior: are protective social factors associated with physical activity?

Although the relationship of psychosocial factors to physical activity has been explored, there is increased interest in how perceptions of the community environment influence behavior. However, few methodological studies have incorporated perceptions of the social and community environment (protective social factors) or addressed key measurement issues. Computer-assisted telephone interviews were administered to a national sample of 1,818 U.S. adults. Unadjusted and multivariate-adjusted odds ratios were calculated to compare active and inactive participants by Protective Social Factors (PSF) scores and selected sociodemographics. Confirmatory factor analysis and reliability analysis suggested strong PSF scale psychometric properties (alpha = .92). After adjustment for potential confounders, a 10-point rise in the PSF score resulted in a 12% increased likelihood of meeting Centers for Disease Control and Prevention/American College of Sports Medicine recommendations. Additional analyses indicated that greater perceived PSFs were associated with meeting these recommendations among Whites but not among African Americans.     

Effects of hypnosis on the features of multiple personality disorder

The authors compared 57 patients with multiple personality disorder (MPD) who had been hypnotized both before and after diagnosis to 38 patients who had not been hypnotized during assessment or treatment. The two groups did not differ on the diagnostic criteria for MPD or in number of personalities. Hypnosis therefore does not have a gross distorting effect on the features of the disorder. Hypnosis may, however, affect the recall of sexual and physical abuse and the manifestation of certain types of alter personality. These include child personalities, personalities of different age, sex, or race, and protectors. The authors hypothesize that the hypnotized group may require hypnosis for access of more traumatic memories held by child personalities.     

25-Hydroxyvitamin D3 metabolism in a human leukemia cell line

Summary 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) is a potent inducer of monocytic differentiation of the human promyelocytic leukemia cell line, HL-60. We have noted that 25-hydroxyvitamin D₃ (25(OH)D₃) in high doses is also capable of promoting monocytic differentiation of this cell line. To test the possibility that the latter activity is due to conversion of 25OHD₃ to 1,25(OH)₂D₃ by HL-60, we exposed HL-60 cells to 25OHD₃ and analyzed the products by HPLC and radioreceptor assay. When chromatographed in the traditional solvent system (isopropanol-hexane), a new peak appears which migrates with authentic 1,25(OH)₂D₃. However, in a solvent system containing dichloromethane, 90% of the peak migrates with another metabolite, 19-Nor-10-Keto-25OHD₃ (19-Nor-25OHD₃). Production of this metabolite is enhanced by living cells and is synthesized by both virgin HL-60 and those which have undergone differentiation. We next determined if authentic 19-Nor-25OHD₃ also promotes differentiation of this cell. As assessed by appearance of the monocyte-specific surface antigen (63D3) and macrophage-specific esterase activity, we find that this metabolite does, in fact, induce monocytic differentiation of HL-60 with a potency of approximately 1/200 that of 1,25(OH)₂D₃ and similar to that of 25OHD₃. In agreement with the effect upon cell maturation, 19-Nor-25OHD₃ displaces³H-1,25(OH)₂D₃ from its HL-60 receptor with an efficiency comparable to 25OHD₃. Hence, HL-60 cells convert 25OHD₃ to 19-Nor-25OHD₃, and 19-Nor-25OHD₃ induces monocytic differentiation of HL-60 with comparable efficiency to its precursor, 25OHD₃.