Prevention of intraperitoneal adhesions: a comparison of noxythiolin and a new povidone-iodine/PVP solution

Peritoneal adhesions were induced in 250 female Wistar rats by the excision and closure of a right lower quadrant parietal peritoneal defect. After closure of the defect each rat was randomly allocated to one of five treatment groups: A, control with no instillate; B, control with Ringer solution; C, noxythiolin 0.5 per cent solution; D, noxythiolin 1 per cent solution; E povidone-iodine/PVP solution. Two millilitres of the appropriate solution were injected into the peritoneal cavity just before closure of a standard 4-cm midline incision. Assessment of adhesion formation was made at 1 week in ignorance of the treatment group. Noxythiolin 1 per cent was more effective than Ringer solution and noxythiolin 0.5 per cent in reducing the mean number of adhesions (P less than 0.05) but was inferior to povidone-iodine/PVP (P less than 0.05). Povidone-iodine/PVP solution significantly reduced the number of adhesions compared with the four other groups. In addition, it significantly reduced the mean length of attachment of each adhesion compared with the two control groups (P less than 0.001).

Topical noxythiolin in colonic healing

Rats were subjected to division and anastomosis of the colon just proximal to the rectum to study the healing of colonic anastomoses. The effect of noxythiolin irrigation of the divided colon before and after anastomosis was investigated and compared with controls. Healing was assessed using five variables--macroscopic and microscopic inspection, bursting pressure and tensile strength estimations and angiography for new vessel formation. The study shows that noxythiolin irrigation of the colon in the rat significantly increases the chance of a sound anastomosis without interfering with healing. Furthermore, it inhibits the formation of adhesions.

Prophylactic intraperitoneal povidone-iodine in alimentary tract surgery

In controlled experiments intraperitoneal povidone-iodine significantly reduced the mortality of mice (p less than 0.01) and rats (p less than 0.01) with induced peritonitis. Povidone-iodine irrigation of the rat colon before and after anastomosis did not interfere with healing or inhibit peritoneal adhesion formation. However, a newly formulated povidone-iodine solution containing increased PVP significantly reduced adhesion formation in a controlled study in rats.

Colonic anastomosis healing. The effect of topical povidone-iodine

The effect of povidone-iodine (0.1% available iodine) irrigation on colonic anastomosis healing was investigated in 196 Sprague-Dawley rats. Each end of the divided colon was irrigated with 5 ml of povidone-iodine solution or with an equal volume of normal saline before anastomosis and again after the anastomosis had been completed. Healing was assessed at 2, 4, 6, 8, 10, and 14 days after operation: macroscopically, mechanically, histologically and angiigraphically. Povidone-iodine irrigation did not impair healing in any way.

Effect of noxythiolin on experimental peritonitis

The intraperitoneal instillation of noxythiolin in the treatment of peritonitis is widespread in clinical practice despite contradictory evidence as to its efficacy. In this light the value of noxythiolin was reappraised by studying its effect in guinea-pigs and mice with induced bacterial peritonitis. Treatment with a 1% solution of noxythiolin reduced the mortality rate of mice by 14% (P less than 0.1). The guinea-pig model proved unreliable giving inconsistent mortality rates throughout. Further studies are required to determine the optimum dose and concentration of noxythiolin while the search for more effective intraperitoneal antiseptics should continue.

150 years after. A tribute to Joseph Lister

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A study of the effect of povidone-iodine on wound healing

The effect of dry powder povidone-iodine (Disadine D.P.) on wound healing was assessed experimentally and clinically. It did not interfere with wound healing macroscopically, histologically or mechanically in Wistar rats. One hundred and one patients undergoing 'clean' elective surgery were included in the controlled clinical study and povidone-iodine did not affect wound healing in any way. In the control group 4% of patients developed infection compared with none of those sprayed with povidone-iodine. No adverse reaction to povidone-iodine was seen in either study. This antiseptic offers a safe alternative to antibiotics for use at operation whenever there is risk of wound infection from operative bacterial contamination.

A reappraisal of the use of antiseptics in surgical practice

The use of antiseptics was reappraised because of the increasing problem of antibiotic-resistant bacteria. A formaldehyde (noxythiolin) and a halogen (povidone-iodine) were investigated, these being the most appropriate antiseptic groups. Povidone-iodine solution significantly reduced the mortality of mice (P less than 0.01) and rats (P less than 0.01) with peritonitis. Noxythiolin (1% and 0.5%) did not. Antiseptic irrigation of the rat colon before and after anastomosis resulted in significantly fewer 'poor' anastomoses (P less than 0.05) without inhibiting healing. Noxythiolin 2.5% and 1% significantly reduced peritoneal adhesion formation in rats, but a newly formulated povidone-iodine solution with increased polyvinylpyrrolidone content was superior to noxythiolin 1% and 0.5%. Povidone-iodine neither inhibited rat abdominal wound healing nor induced bacterial resistance. In 3 subsequent controlled clinical trials a dry-powder povidone-iodine formulation halved wound infection after grid-iron appendicectomy (P less than 0.025), reduced infection in elective 'clean' surgery, and significantly reduced infection after a wide variety of 'potentially contaminated' abdominal procedures (P less than 0.01). A return to the principles of Lister is advocated.

Noxytiolin and peritoneal adhesion formation

Clinical and experimental studies have suggested that intraperitoneal noxytiolin prevents adhesion formation. A reliable experimental animal model was therefore established and the effect of noxytiolin on adhesion formation was evaluated in a controlled trial using 80 rats. All 40 rats given Ringer solution developed adhesions, whereas in 7 out of 40 given noxytiolin no adhesions were found (P less than 0-02). Noxytiolin reduced both the total and the mean number of adhesions formed (P less than 0-2) and their mean length of attachment (P less than 0-05). The anti-adhesive effect of noxytiolin may be due to its anticoagulant, cytotoxic or antibacterial properties.

Absence of bacterial resistance to povidone iodine

Povidone iodine is now being increasingly used in hospitals as an antiseptic. The possible habituation of bacteria to iodine was studied by serial passage of two strains of Pseudomonas aeruginosa, two strains of Escherichia coli, two strains of Klebsiella aerogenes, and one strain of Serratia marcescens in subinhibitory concentrations. After 20 passages, no significant change was observed in the minimal inhibitory concentration, minimal bactericidal concentration, and killing times between parent strains and 20th subcultures under standardized conditions.

Prophylactic interparietal povidone-iodine in abdominal surgery

This study sought to determine in a district general hospital (a) the frequency and nature of bacterial contamination at operation, (b) the incidence of consequent infection and (c) the prophylactic effect, if any, of interparietal povidone-iodine against postoperative wound infection. Bacterial contamination was shown in 49 per cent of all the abdominal surgical wounds at the end of operation. From 61 per cent of the subsequently infected wounds, organisms identified as contaminants at operation were again found. Interparietal instillation of povidone-iodine resulted in a statistically significant reduction in wound infection (P less than 0.01) in treated patients compared with untreated, randomized, matched controls. It was of significant value in cases of intestinal resection and peritonitis, in obese patients and in those with paramedian incisions. Laboratory studies indicate that povidone-iodine does not induce bacterial resistance. This chemical antibacterial agent may thus provide a preferable alternative to antibiotics in preventing such infections.

An antibiotic policy for surgical patients

This paper offers guidance on antibiotic usage in surgical patients. A policy is outlined rather than the comprehensive coverage of every surgical situation. The principles of antibiotic prescribing are given. The antibiotics available and their routes of administration are reviewed. Indications for the prophylactic and therapeutic use of antibiotics are discussed. Factors causing the failure of antibiotic therapy are considered in brief.

Appendicitis and mimicking conditions. A prospective study

A prospective study of 444 consecutive patients diagnosed as having acute appendicitis was carried out in a district general hospital. The appendix was acutely inflamed, gangrenous, or perforated in 346 patients. Diagnostic error, 22% overall, was twice as common in females as in males. Organisms were isolated from the outer appendix wall in 117 patients, isolation increasing with the severity of inflammation. 12% of children under 11 had mesentric adenitis, 10% of all females had gynaecological lesions, and 14% of patients over 50 had acute diverticulitis. In only 6% of patients was no abnormality found at operation, and in every case the disorder was dealt with through the gridiron incision.

Aetiology and prevention of wound infection in appendicetomy

A study at the Reading District Hospitals on 451 consecutive patients undergoing appendicectomy through grid-iron incisions sought to determine factors influencing wound infection and the effects of a prophylactic wound-spraying procedure. Wound infection increased with the severity of appendicular inflammation and was well correlated with the degree and nature of bacterial contamination at the time of wound closure.

The infection rate was reduced by about one-half when either an aerosol dry-powder formulation of povidone iodine (Disadine D. P.) or an aerosol antibiotic powder spray containing neomycin, bacitracin and polymixin (Dispray) was sprayed on the wound before and after closure. The reduction of infection achieved by spraying with pouidine iodine was statistically significant (P < 0.025). The results of the polyantibiotic spraying did not quite reach significance (P < 0.06).

The povidone iodine dry powder was better overall since it reduced infection in all degrees of appendicular inflammation, in all age groups and in enlarged, drained, contaminated and non-contaminated wounds without the attendant disadvantages of antibiotics.