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Ten years experience with povidone-iodine in heart surgery
ffournal of Hospital Infection (l 985) 6 (Supplement), 117-121
T e n years e x p e r i e n c e with p o v i d o n e - i o d i n e in heart surgery W. P. K l 6 v e k o r n , H. M e i s n e r a n d F. S e b e n i n g
Department of Cardiovascular Surgery, German Heart Centre, Munich Lothstrasse 11, D-8000, Munich 2, F R G Summary: Ten years experience with povidone-iodine (PVP-I) (10%) ('Beta-isodona') in 7566 patients undergoing open-heart operations in the German Heart Centre, Munich, is reported. Povidone-iodine was used pre-, intra- and postoperatively for skin and wound disinfection according to a regime introduced more than 10 years ago and retained unchanged until today. The incidence of minor, superficial wound healing defects was 5%, whereas severe, deep sternal or retrosternal infections occurred in 0"5% of all patients. Superficial infections are no risk to the patient and can be treated successfully with local application of PVP-I. Deep infections, however, are associated with a mortality of about 40% despite the use of antibiotics and continuous wound irrigation with PVP-I (0.5%). Many factors contribute to the risk of these infections and only meticulous observation of aseptic and surgical technique, the prophylactic and therapeutic use of highly effective antibiotics, as well as the exclusion of sources of exogenous bacteria, can further reduce the incidence of these complications.
Introduction B e t w e e n M a y 1974 a n d M a y 1984 in the D e p a r t m e n t of C a r d i o v a s c u l a r S u r g e r y at the G e r m a n H e a r t C e n t r e , M u n i c h , 13,895 o p e r a t i o n s on a d u l t s a n d c h i l d r e n have b e e n p e r f o r m e d . T h i s p a p e r d e s c r i b e s the results of 7566 o p e n - h e a r t o p e r a t i o n s i n c l u d i n g a o r t o - c o r o n a r y b y p a s s grafts. T h e use of p r o s t h e t i c m a t e r i a l for h e a r t valves, v a s c u l a r p r o s t h e s e s a n d p a c e m a k e r s creates a p a r t i c u l a r risk of infection, o s t e o m y e l i t i s , m e d i a s t i n i t i s , aortitis a n d e n d o c a r d i t i s , all h a v e a h i g h m o r t a l i t y . A f t e r detailed b a c t e r i o l o g i c a l i n v e s t i g a t i o n u s i n g A g a r f l e x skin c o n t a c t c u l t u r e s w h i c h were d o n e in association w i t h K a n z a n d c o w o r k e r s (1975) at the H y g i e n e I n s t i t u t e , H a m b u r g U n i v e r s i t y , a p r e - o p e r a t i v e skin d i s i n f e c t i o n r e g i m e u s i n g p o v i d o n e - i o d i n e ( P V P - I ) ( ' B e t a - i s o d o n a ' ) was i n t r o d u c e d into o u r unit. T h i s r e g i m e has g i v e n g o o d results a n d so has b e e n r e t a i n e d v i r t u a l l y u n c h a n g e d for 10 years. Details of the m e t h o d a n d its results are d e s c r i b e d below.
Method of disinfection D i s i n f e c t i o n s t a r t e d the day b e f o r e o p e r a t i o n . T h e o p e r a t i o n area was s h a v e d wet w i t h an a l c o h o l c o n t a i n i n g d i s i n f e c t a n t s h a v i n g f o a m , t a k i n g 0195-6701/85/06A 117 + 05 $02.00/0
~:) 1985 T h e t tospital Infection Society
117
118
W. P. K l f v e k o r n
et aL
care to avoid skin injury. T h e patient then b a t h e d in 1:1000 P V P - I solution for 30 min, washing with P V P - I scrub ('Beta-isodona' soap). A ft erw ards the patients dried themselves and u n d i l u t e d P V P - I solution (containing 10% available iodine) was applied to the skin of the operating area. T h e patients p u t on new gowns and the bedclothes were changed. T h e s e measures r e d u c e d the skin flora by 97% and the following m o r n i n g there was still a r e d u c t i o n of 75% as d e t e r m i n e d by skin contact cultures (K anz et al., 1978). After insertion of an iv line p r e - o p e r a t i v e l y the patient receives a p r o p h y lactic antibiotic (cefuroxime, 20 mg/kg b o d y weight). T h e skin of the operation site is then washed for 5 m i n with P V P - I scrub, t hen dried with sterile towels and treated four times with P V P - I (10%) solution. T h e solution is then r e m o v e d with sterile water and the skin is dried to allow adhesion of a sterile film. Results
T h e measures described have significantly r e d u c e d postoperative w o u n d p r o b lems w hen c o m p a r e d with incidence of w o u n d infection in the years before 1974. Superficial w o u n d infections w hi ch are only secondary to serous fluid a c c u m u l a t i o n and tissue necroses, and which were originally sterile but acquired organisms postoperatively o c c u r r e d in < 5 % of patients. T h e s e averaged 5% over 10 years, but declined f r o m nearly 8% in 1974 to about 3% in 1983. D e e p infections which are considerably m o r e serious have o c c u r r e d in less than 0"5% of patients, but t hey represent a substantial risk and carry a high mortality even today. Several factors predispose to poor wound-healing: overw ei ght and diabetes are most i m p o r t a n t . Infections are also m ore c o m m o n in smokers and patients with p u l m o n a r y h y p e r t e n s i o n or chronic obstructive airways disease. Excessive h a e m o r r h a g e postoperatively and the need for m o r e than 3 days artificial ventilation are also risk factors. We have not f o u n d any correlation with age or sex. Table I. Bacteriological isolates from intrathoracic wound infections
1. 2. 3. 4. 5. 6. 7.
Staph. epidermidis Staph. aureus Strep. faecalis K. aerogenes Ps. aeruginosa E. coli Cand. albicans
8.
No bacterial growth Total
Number of isolates
(%)
11 6
(31 ) (17)
2
(5)
5 4 2 1 5 36
(14) (11) (5) (3) (14) (100)
Povidone-iodine in heart surgery
119
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Table I gives details of the bacteria found in 36 cases with severe intrathoracic w o u n d - h e a l i n g impairment, including those cases where bacteraemia caused by the intrathoracic infection had led to endocarditis, aortitis or pericarditis. All other cases of endocarditis, aortitis or pericarditis not associated with thoracic w o u n d healing defects were excluded from this specific study. Over 50% of the infections were caused by staphylococci-principally Staphylococcus epidermidis. T h e failure to grow bacteria from five patients despite repeated blood cultures and w o u n d swabs taken during re-operation (re-thoracotomy and institution of irrigation drainage) is surprising but m a y be caused by the high doses of antibiotics (cefuroxime, piperacillin, tobramycin, g e n t a m i c i n - - g i v e n in different combinations) which all these patients received. In these cases it cannot be proved that the intra-thoracic w o u n d healing impairment was due to infection, although the clinical s y m p t o m s were suggestive. T h e r a p y of w o u n d h e a l i n g i m p a i r m e n t s
T h e r a p y as outlined in Table II is used depending on the type and site of infection. Serous fluid accumulations are drained, if possible by aspiration. M a n y infections are prevented by this proceedure. Necrotic fat or muscle must be removed, and so secondary infection is almost unavoidable following a further skin incision. Fistulae caused by sutures or sternal wires are always infected and require removal of the foreign material. Fistulae from infected transvenous or epicardial pacemaker wires are a particular problem as major operations (in some cases using the heart lung machine) may be needed to remove the wires. Sternal osteomyelitis, mediastinitis and aortitis are indications for rcthoracotomy. T h e entire w o u n d is irrigated with undiluted PVP-I solution (10% iodine) once the thorax has been opened and swabs taken for bacteriology. For sternal osteomyelitis the diseased bone is resected and the sternum re-sutured. For mediastinitis and aortitis we use a continuous irrigation with 0"5% PVP-I solution (50 ml PVP-I 10% solution in 950 ml NaC1 0"9% solution) after closing the s t e r n u m [as described by Meisner et al. (1978) and Sebening et al. (1980)]. T h e solution is passed into the upper mediastinum, via two infusion tubes and runs out through two retrosternal drains containing multiple perforations. Irrigation is continued until the fluid is no longer turbid (1 5 days). A b o u t 4 1 of solution are used per day. Of 36 patients, 21 (58-3%) survived. Six of the 15 who died (16"7%) had uncontrolled sepsis; cardiac and renal failure led to the deaths of the remainder, although in the latter it is not possible to decide the extent to which their infection contributed to their death.
P o v i d o n e - i o d i n e in heart s u r g e r y
121
Discussion
I n t r a t h o r a c i c infections f o l l o w i n g m e d i a n s t e r n o t o m y are a serious p r o b l e m in cardiac s u r g e r y . B e c a u s e of the h i g h risk a n d n e e d for p r o l o n g e d t h e r a p y , p r o p h y l a x i s is m o s t i m p o r t a n t . O u r rate o f i n f e c t i o n o f < 0"5% c o m p a r e s f a v o u r a b l y with rates o f 0"4 to 6 % r e c o r d e d in the literature ( E n g e l m a n n et al., 1973; O c h n e r , M i l i s & W o o l v e r t o n , 1972; W e i n s t e i n et al., 1976). O t t e t al. (1980) o b t a i n e d similar figures with severe w o u n d i n f e c t i o n s in 6 1 / 9 2 7 9 sternotomies. I n general, t h e r e s e e m s to be a d e c r e a s i n g t r e n d in severe i n f e c t i o n s after o p e n h e a r t s u r g e r y o v e r the last decade. Several factors m a y h a v e c o n t r i b u t e d to this: besides the use of m o r e effective d i s i n f e c t i o n a n d a b e t t e r c o n t r o l of o p e r a t i n g r o o m h y g i e n e , m o d e r n a n t i b i o t i c s have c e r t a i n l y p l a y e d an i m p o r t a n t role. I n o u r e x p e r i e n c e a f u r t h e r r e d u c t i o n of the risk o f w o u n d i n f e c t i o n s was a c h i e v e d w h e n r e s o r b a b l e s u t u r e s w e r e u s e d m o r e f r e q u e n t l y after 1981. B e c a u s e o f the m u l t i t u d e of factors c o n t r i b u t i n g to the risk of w o u n d i n f e c t i o n s and the c o m p l e x i t y o f t h e r a p y a b e t t e r c o n t r o l l e d s t u d y s h o u l d be p e r f o r m e d to f u r t h e r investigate the significance o f risk factors a n d the influence o f t h e r a p y . H o w e v e r , b e c a u s e of t h e relatively low i n c i d e n c e o f these infections, s u c h a trial w o u l d r e q u i r e a large n u m b e r o f p a t i e n t s to o b t a i n results o f statistical value. I n r e g a r d to disinfection, h a v i n g used P V P - I 1 0 % for 10 years n o w , we see no r e a s o n to c h a n g e a p r o v e n d i s i n f e c t a n t plan, especially since we have o b s e r v e d n e i t h e r allergic n o r t h y r o i d d i s o r d e r s , despite the large v o l u m e s used.
References
Engeiman, R. M., Williams, C. D., Gouge, T. H., Chase, R. M., Falk, E. A., Boyd, A. D. & Reed, G. E. (1973). Mediastinitis following open-heart surgery. Archives of Surgery 107, 772-778. Kanz, E., Gran, H., Meisner, li., FIolper, K. & Sebening, F. (1978). Preoperative disinfection with 'Betaisodona' microbicides before intra-thoracic surgery. Proceedings of the W'orld Congress on Antisepsis, pp. 4-8--50. liP Publishing Co., New York. Meisner, H., Struck, E., Schmidt-Habelmann, P. & Sebening, F. (1978). Management of postoperative wound infection in cardiothoracic surgery. Proceedings of the World Congress on Antisepsis, pp. 126-129. HP Publishing Co., New York. Ochsner, J. L., Mills, N. L. & Woolverton, W. C. (1972). Disruption and infection of the median sternotomy incision. Journal of Cardiovascular Surgery 13, 394-399. Ott, D. A., Cooley, D. A., Soils, R. T. & Harrison, C. B. (1980). Wound complications after median sternotomy: a study of 61 patients from a consecutive series of 9279. Bulletin of tile Texas Heart Institute 7, 104-111. Sebening, F., Meisner, li. & K16vekorn, W. P. (1980). Six years' experience with Betadine solution in heart surgery. Proceedings of the H World Congress on Antisepsis, pp. 151 154. liP Publishing Co., New York. Weinstein, R. A., Jones, E. L., Schwarzmann, S. W. E., Hatcher, C. R. Jr (1976). Sternal osteomyelitis and mediastinitis after open-heart operation: pathogenesis and prevention. Annals of Thoracic Surgery 21,442~44.
T e n years e x p e r i e n c e with p o v i d o n e - i o d i n e in heart surgery W. P. K l 6 v e k o r n , H. M e i s n e r a n d F. S e b e n i n g
Department of Cardiovascular Surgery, German Heart Centre, Munich Lothstrasse 11, D-8000, Munich 2, F R G Summary: Ten years experience with povidone-iodine (PVP-I) (10%) ('Beta-isodona') in 7566 patients undergoing open-heart operations in the German Heart Centre, Munich, is reported. Povidone-iodine was used pre-, intra- and postoperatively for skin and wound disinfection according to a regime introduced more than 10 years ago and retained unchanged until today. The incidence of minor, superficial wound healing defects was 5%, whereas severe, deep sternal or retrosternal infections occurred in 0"5% of all patients. Superficial infections are no risk to the patient and can be treated successfully with local application of PVP-I. Deep infections, however, are associated with a mortality of about 40% despite the use of antibiotics and continuous wound irrigation with PVP-I (0.5%). Many factors contribute to the risk of these infections and only meticulous observation of aseptic and surgical technique, the prophylactic and therapeutic use of highly effective antibiotics, as well as the exclusion of sources of exogenous bacteria, can further reduce the incidence of these complications.
Introduction B e t w e e n M a y 1974 a n d M a y 1984 in the D e p a r t m e n t of C a r d i o v a s c u l a r S u r g e r y at the G e r m a n H e a r t C e n t r e , M u n i c h , 13,895 o p e r a t i o n s on a d u l t s a n d c h i l d r e n have b e e n p e r f o r m e d . T h i s p a p e r d e s c r i b e s the results of 7566 o p e n - h e a r t o p e r a t i o n s i n c l u d i n g a o r t o - c o r o n a r y b y p a s s grafts. T h e use of p r o s t h e t i c m a t e r i a l for h e a r t valves, v a s c u l a r p r o s t h e s e s a n d p a c e m a k e r s creates a p a r t i c u l a r risk of infection, o s t e o m y e l i t i s , m e d i a s t i n i t i s , aortitis a n d e n d o c a r d i t i s , all h a v e a h i g h m o r t a l i t y . A f t e r detailed b a c t e r i o l o g i c a l i n v e s t i g a t i o n u s i n g A g a r f l e x skin c o n t a c t c u l t u r e s w h i c h were d o n e in association w i t h K a n z a n d c o w o r k e r s (1975) at the H y g i e n e I n s t i t u t e , H a m b u r g U n i v e r s i t y , a p r e - o p e r a t i v e skin d i s i n f e c t i o n r e g i m e u s i n g p o v i d o n e - i o d i n e ( P V P - I ) ( ' B e t a - i s o d o n a ' ) was i n t r o d u c e d into o u r unit. T h i s r e g i m e has g i v e n g o o d results a n d so has b e e n r e t a i n e d v i r t u a l l y u n c h a n g e d for 10 years. Details of the m e t h o d a n d its results are d e s c r i b e d below.
Method of disinfection D i s i n f e c t i o n s t a r t e d the day b e f o r e o p e r a t i o n . T h e o p e r a t i o n area was s h a v e d wet w i t h an a l c o h o l c o n t a i n i n g d i s i n f e c t a n t s h a v i n g f o a m , t a k i n g 0195-6701/85/06A 117 + 05 $02.00/0
~:) 1985 T h e t tospital Infection Society
117
118
W. P. K l f v e k o r n
et aL
care to avoid skin injury. T h e patient then b a t h e d in 1:1000 P V P - I solution for 30 min, washing with P V P - I scrub ('Beta-isodona' soap). A ft erw ards the patients dried themselves and u n d i l u t e d P V P - I solution (containing 10% available iodine) was applied to the skin of the operating area. T h e patients p u t on new gowns and the bedclothes were changed. T h e s e measures r e d u c e d the skin flora by 97% and the following m o r n i n g there was still a r e d u c t i o n of 75% as d e t e r m i n e d by skin contact cultures (K anz et al., 1978). After insertion of an iv line p r e - o p e r a t i v e l y the patient receives a p r o p h y lactic antibiotic (cefuroxime, 20 mg/kg b o d y weight). T h e skin of the operation site is then washed for 5 m i n with P V P - I scrub, t hen dried with sterile towels and treated four times with P V P - I (10%) solution. T h e solution is then r e m o v e d with sterile water and the skin is dried to allow adhesion of a sterile film. Results
T h e measures described have significantly r e d u c e d postoperative w o u n d p r o b lems w hen c o m p a r e d with incidence of w o u n d infection in the years before 1974. Superficial w o u n d infections w hi ch are only secondary to serous fluid a c c u m u l a t i o n and tissue necroses, and which were originally sterile but acquired organisms postoperatively o c c u r r e d in < 5 % of patients. T h e s e averaged 5% over 10 years, but declined f r o m nearly 8% in 1974 to about 3% in 1983. D e e p infections which are considerably m o r e serious have o c c u r r e d in less than 0"5% of patients, but t hey represent a substantial risk and carry a high mortality even today. Several factors predispose to poor wound-healing: overw ei ght and diabetes are most i m p o r t a n t . Infections are also m ore c o m m o n in smokers and patients with p u l m o n a r y h y p e r t e n s i o n or chronic obstructive airways disease. Excessive h a e m o r r h a g e postoperatively and the need for m o r e than 3 days artificial ventilation are also risk factors. We have not f o u n d any correlation with age or sex. Table I. Bacteriological isolates from intrathoracic wound infections
1. 2. 3. 4. 5. 6. 7.
Staph. epidermidis Staph. aureus Strep. faecalis K. aerogenes Ps. aeruginosa E. coli Cand. albicans
8.
No bacterial growth Total
Number of isolates
(%)
11 6
(31 ) (17)
2
(5)
5 4 2 1 5 36
(14) (11) (5) (3) (14) (100)
Povidone-iodine in heart surgery
119
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0
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~
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~0
t=L 0
~
= ~?'~
E
~tt~
e~--
~
~
~ ~ ~ "~ i 6 oo~ ~
E
9 k.
& ~0"~
0 t.
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8 >
.o
i .<
+-
120
W. P. Kl6vekorn
et aL
Table I gives details of the bacteria found in 36 cases with severe intrathoracic w o u n d - h e a l i n g impairment, including those cases where bacteraemia caused by the intrathoracic infection had led to endocarditis, aortitis or pericarditis. All other cases of endocarditis, aortitis or pericarditis not associated with thoracic w o u n d healing defects were excluded from this specific study. Over 50% of the infections were caused by staphylococci-principally Staphylococcus epidermidis. T h e failure to grow bacteria from five patients despite repeated blood cultures and w o u n d swabs taken during re-operation (re-thoracotomy and institution of irrigation drainage) is surprising but m a y be caused by the high doses of antibiotics (cefuroxime, piperacillin, tobramycin, g e n t a m i c i n - - g i v e n in different combinations) which all these patients received. In these cases it cannot be proved that the intra-thoracic w o u n d healing impairment was due to infection, although the clinical s y m p t o m s were suggestive. T h e r a p y of w o u n d h e a l i n g i m p a i r m e n t s
T h e r a p y as outlined in Table II is used depending on the type and site of infection. Serous fluid accumulations are drained, if possible by aspiration. M a n y infections are prevented by this proceedure. Necrotic fat or muscle must be removed, and so secondary infection is almost unavoidable following a further skin incision. Fistulae caused by sutures or sternal wires are always infected and require removal of the foreign material. Fistulae from infected transvenous or epicardial pacemaker wires are a particular problem as major operations (in some cases using the heart lung machine) may be needed to remove the wires. Sternal osteomyelitis, mediastinitis and aortitis are indications for rcthoracotomy. T h e entire w o u n d is irrigated with undiluted PVP-I solution (10% iodine) once the thorax has been opened and swabs taken for bacteriology. For sternal osteomyelitis the diseased bone is resected and the sternum re-sutured. For mediastinitis and aortitis we use a continuous irrigation with 0"5% PVP-I solution (50 ml PVP-I 10% solution in 950 ml NaC1 0"9% solution) after closing the s t e r n u m [as described by Meisner et al. (1978) and Sebening et al. (1980)]. T h e solution is passed into the upper mediastinum, via two infusion tubes and runs out through two retrosternal drains containing multiple perforations. Irrigation is continued until the fluid is no longer turbid (1 5 days). A b o u t 4 1 of solution are used per day. Of 36 patients, 21 (58-3%) survived. Six of the 15 who died (16"7%) had uncontrolled sepsis; cardiac and renal failure led to the deaths of the remainder, although in the latter it is not possible to decide the extent to which their infection contributed to their death.
P o v i d o n e - i o d i n e in heart s u r g e r y
121
Discussion
I n t r a t h o r a c i c infections f o l l o w i n g m e d i a n s t e r n o t o m y are a serious p r o b l e m in cardiac s u r g e r y . B e c a u s e of the h i g h risk a n d n e e d for p r o l o n g e d t h e r a p y , p r o p h y l a x i s is m o s t i m p o r t a n t . O u r rate o f i n f e c t i o n o f < 0"5% c o m p a r e s f a v o u r a b l y with rates o f 0"4 to 6 % r e c o r d e d in the literature ( E n g e l m a n n et al., 1973; O c h n e r , M i l i s & W o o l v e r t o n , 1972; W e i n s t e i n et al., 1976). O t t e t al. (1980) o b t a i n e d similar figures with severe w o u n d i n f e c t i o n s in 6 1 / 9 2 7 9 sternotomies. I n general, t h e r e s e e m s to be a d e c r e a s i n g t r e n d in severe i n f e c t i o n s after o p e n h e a r t s u r g e r y o v e r the last decade. Several factors m a y h a v e c o n t r i b u t e d to this: besides the use of m o r e effective d i s i n f e c t i o n a n d a b e t t e r c o n t r o l of o p e r a t i n g r o o m h y g i e n e , m o d e r n a n t i b i o t i c s have c e r t a i n l y p l a y e d an i m p o r t a n t role. I n o u r e x p e r i e n c e a f u r t h e r r e d u c t i o n of the risk o f w o u n d i n f e c t i o n s was a c h i e v e d w h e n r e s o r b a b l e s u t u r e s w e r e u s e d m o r e f r e q u e n t l y after 1981. B e c a u s e o f the m u l t i t u d e of factors c o n t r i b u t i n g to the risk of w o u n d i n f e c t i o n s and the c o m p l e x i t y o f t h e r a p y a b e t t e r c o n t r o l l e d s t u d y s h o u l d be p e r f o r m e d to f u r t h e r investigate the significance o f risk factors a n d the influence o f t h e r a p y . H o w e v e r , b e c a u s e of t h e relatively low i n c i d e n c e o f these infections, s u c h a trial w o u l d r e q u i r e a large n u m b e r o f p a t i e n t s to o b t a i n results o f statistical value. I n r e g a r d to disinfection, h a v i n g used P V P - I 1 0 % for 10 years n o w , we see no r e a s o n to c h a n g e a p r o v e n d i s i n f e c t a n t plan, especially since we have o b s e r v e d n e i t h e r allergic n o r t h y r o i d d i s o r d e r s , despite the large v o l u m e s used.
References
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