Leeture 146
Effect of Haematocrit on Wound Healing in Children ]. Viljanto Department of Paediatrics, Division of Surgery, Turku University Central Hospital, Turku, Finland
The effects of mild or moderate normovolaemic anaemia on wound healing (WH) continue to be debatable. The results of animal experiments and clinical experience are somewhat controversial. In this study, sixty-six boys, aged from 5 to 15, mean 10.1 years, were routinely operated on for a unilateral inguinal hernia, after which their WH was studied by the Cellstic device. Based on differential count of wound cells and their mutual transformed cell to cell ratios it was found that the optimum level of haematocrit (Hct) for WH was 3739 % with haemoglobin (Hb) values of 12.0-12.4 g/100 ml. Hct values under and over these limits began 10 retard WH significantly (p < 0.02) without any visual signs of delay in WH. Both values are below the age adjusted means but just above the lower limits of normal. It is thus allowed, for the majority of healthy children with normal blood values, a mild decrease of Hct during the operation without any harmful effect on WH.
Key words Wound healing - Haematocrit - Inguinal hernia
Die Wirkung des Hämatokrits auf die Wundheilung bei Kindern Die Wirkung einer geringen normovolaemischen Anämie auf die Wundheilung ist immer noch umstritten. Die Resultate von Tierexperimenten und die klinische Erfahrung sind unterschiedlich. In der vorliegenden Untersuchung wurden 66 Kinder von 5 bis 15 Jahren, Durchschnittsalter 10,1 Jahre, routinemäßig an einem einseitigen Leistenbruch operiert und postoperativ die Wundheilung mit Hilfe der CellsticDrainagen-Methode zur Bestimmung der Wundheilung untersucht. Aufgrund der Differenzierung der Wundzellen und ihrer Transformation konnte festgestellt werden, daß der Hämatokrit für eine optimale Wundheilung 37 % bis 39 % betrug, bei Hämoglobinwerten von 12.0 bis 12.4 g/100 ml. Hämatokritwerte unter und über diesen Grenzwerten verzögerten die Wundheilung (p~0,02), jedoch ohne sichtbare Zeichen einer Wundheilungsstörung. Die beiden Werte lagen unter den altersstandardisierten Mittelwerten, aber gerade über der untersten Grenze von Normalwerten. So ist für die Mehrzahl der gesunden Kinder mit normalen Hb- und HkWerten eine geringe Verminderung des Hämatokrits während der Operation nicht von negativer Wirkung auf die Wundheilunggefol~.
Schlüsselwörter Wundheilungsstörungen - Hämatokrit Leistenbruch
Diverse opinions exist on the effect of mild normovolaemic anaemia and polycythaemia on wound healing (WH) after surgery (1, 2, 4) and little information is available on the optimum level of haematocrit (Hct) for WH in children. Physiologically, blood haemoglobin (Hb) concentration undergoes remarkable changes after the birth. Hb values of 16-17 g/100 ml in the newborn may drop to 10-12 g/100 ml at the age of 2-3 months, after which they gradually increase to the
Received July 17, 1988 Z Kinderchir 45 (1990) 146-147 © Hippokrates Verlag Stuttgart
level of adults. Accordingly, reference values of Hct change during the first months of life. By contrast, mean corpuscular volurne of erythrocytes (MCV) increases slowly from 70J.l3 at the age of three months up to 90J.l3 in older adults (3). As a consequence of these changes together with vascular growth, increase in cardiac output volume and arterial blood pressure Iocal tissue perfusion and oxygen delivery are not only age-dependent but individual and locally different. In cases of operative bleeding and blood transfusion the final effect on WH depends on the amount of blood lass, time lapse before transfusion and storing time of the bank blood. Hence, WH studies in man should be performed individually or in standardised conditions for selected groups of patients, although they are made in connection with routine operations.
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Summary
E.ffect ofHaematocrit on Wound Healing in Children
Haematocrit (%) Number of patients Age (yrs) ± sd MA/PMN 48 ± sd MA/M048 ± sd MA/CAC 48 ± sd
35-36
37-38
39
~
15 8.42±2.7 6.21 ± 1.4 13.96± 1.3 9.80± 1.8
20 9.89±3.0 6.58± 1.3 14.87±0.8 10.27 ± 1.6
10 11.93±2.9 6.39±2.4 14.90± 1.4 11.14±2.7
21 10.59±3.1 5.30± 1.9 13.41 ± 1.2 9.33±2.1
Patients and methods From a patient series of 990 children, routinely operated on during a five-year period and studied for WH by the Cellstic device (5), 66 boys, aged from 5 to 15 years, mean 10.1 years, were selected for this study. All of them had an unilateral inguinal hemia but were otherwise healthy both clinically and according to routine laboratory investigations. For all of them hemia operation was performed similarly through a 5 to 7 cm long groin skin incision. Bleeding was minimal and no complications were found in WH. At the end of each operation, before closing the skin wound, one end of a Cellstic drain, composed of standard-sized cellulose spange inside a Silastic® tube, was placed subcutaneously between the wound edges. The Cellstics were removed after 48 hours and the wound ceIls harvested inside the tube were washed out by aretrograde injection technique, cytocentrifuged, and stained with May-Grünwald-Giemsa for differential count of the cells. Transformed mutual ceIl 10 cell ratios were then calculated, from which the speed of WH could be determined.
At the age of 5-15 years transformed ratios of macrophages to polymorphonuclear (PMN) cells at hour 48 (MAlPMN4S )' 10 monocytes (MAlM04S ) and 10 cell aggregation centers (MAlCAC4S ) (6), respectively, were highest, when Hct varied between 37 and 39 % (Table 1), indicating that WH was most advanced in these patients. CorresJ)9nding values of Hb varied between 12.0 and 12.5 g/100 ml. Hct values under and over these limits began to retard WH significantly (p < 0.02) without any visual signs of delay. Comparison of these values with age-adjusted references (3) revealed that both Hct and Hb were below the normal means hut just above the lower limits of normal.
Although all patients in this study healed without any complications their WH was different at the cellular level. This is natural because only after remarkable defects in wound cell population a clinically manifest wound complication will occur. Several factors affect WH coincidentally in seriously sick patients. Therefore it is important to know the role of these factors and to correct them.
References
2
3 4
5 6
7
Goodson WH, Hunt TK: Wound healing and the diabetic patient. Surg Gynecol Obstet 149 (1979) 600-608 Heughan C, Chir B, Grislis G, Hunt TK: The effect of anemia on wound healing. Ann Surg 179 (1974) 163-167 Nathan DG, Oski FA: Hematology of Infancy and Childhood. Vol I. Philadelphia: Saunders 1987. Taylor DEM, Whamond }5, Penhallow JE: Effects of hemorrhage on wound strength and fibroblast function. Sr J Surg 74 (1987) 316-319 Viljanto j: Cellstic: A device for wound healing studies in man. J Surg Res 20 (1976) 115-119 Viljanto j, Rajamäki A, Renvall 5, Raekallio]: Cell aggregation centers initial strength elements in human wound healing. J Surg Res 29 (1980) 414-421 Viljanto j, Savunen T: Prediction of wound tensile strength by the Cellstic device. Abstr. ESSR XXII Congress, Aarhus 1987
}. Viljanto, M. D.
Discussion Wound cell analysis is a reliable indirect method for early evaluation of WH process. Although the cells harvested by the Cellstic device during the first 48 hours after sur-
40
gery reflect the quality and intensity of the inflammatory phase of WH they still are predictive for wound tensile strength two to three weeks forward, as was shown earlier in an experimental study (7). Defects in the inflammatory phase oI healing, especially the elimination of macrophages, directly caused failure of subsequent fibroblast growth and collagen synthesis (1).
1
Results
147
Dept. of Paediatrics Division of Surgery Turku University Central Hospital SF-20520 Turku 52, Finland
Downloaded by: National University of Singapore. Copyrighted material.
Table 1 Transformed mutual ratios of Cellstic cells according to haematocrit values 48 hours after operations.
Z Kinderchir 45 (1990)
Effect of Haematocrit on Wound Healing in Children ]. Viljanto Department of Paediatrics, Division of Surgery, Turku University Central Hospital, Turku, Finland
The effects of mild or moderate normovolaemic anaemia on wound healing (WH) continue to be debatable. The results of animal experiments and clinical experience are somewhat controversial. In this study, sixty-six boys, aged from 5 to 15, mean 10.1 years, were routinely operated on for a unilateral inguinal hernia, after which their WH was studied by the Cellstic device. Based on differential count of wound cells and their mutual transformed cell to cell ratios it was found that the optimum level of haematocrit (Hct) for WH was 3739 % with haemoglobin (Hb) values of 12.0-12.4 g/100 ml. Hct values under and over these limits began 10 retard WH significantly (p < 0.02) without any visual signs of delay in WH. Both values are below the age adjusted means but just above the lower limits of normal. It is thus allowed, for the majority of healthy children with normal blood values, a mild decrease of Hct during the operation without any harmful effect on WH.
Key words Wound healing - Haematocrit - Inguinal hernia
Die Wirkung des Hämatokrits auf die Wundheilung bei Kindern Die Wirkung einer geringen normovolaemischen Anämie auf die Wundheilung ist immer noch umstritten. Die Resultate von Tierexperimenten und die klinische Erfahrung sind unterschiedlich. In der vorliegenden Untersuchung wurden 66 Kinder von 5 bis 15 Jahren, Durchschnittsalter 10,1 Jahre, routinemäßig an einem einseitigen Leistenbruch operiert und postoperativ die Wundheilung mit Hilfe der CellsticDrainagen-Methode zur Bestimmung der Wundheilung untersucht. Aufgrund der Differenzierung der Wundzellen und ihrer Transformation konnte festgestellt werden, daß der Hämatokrit für eine optimale Wundheilung 37 % bis 39 % betrug, bei Hämoglobinwerten von 12.0 bis 12.4 g/100 ml. Hämatokritwerte unter und über diesen Grenzwerten verzögerten die Wundheilung (p~0,02), jedoch ohne sichtbare Zeichen einer Wundheilungsstörung. Die beiden Werte lagen unter den altersstandardisierten Mittelwerten, aber gerade über der untersten Grenze von Normalwerten. So ist für die Mehrzahl der gesunden Kinder mit normalen Hb- und HkWerten eine geringe Verminderung des Hämatokrits während der Operation nicht von negativer Wirkung auf die Wundheilunggefol~.
Schlüsselwörter Wundheilungsstörungen - Hämatokrit Leistenbruch
Diverse opinions exist on the effect of mild normovolaemic anaemia and polycythaemia on wound healing (WH) after surgery (1, 2, 4) and little information is available on the optimum level of haematocrit (Hct) for WH in children. Physiologically, blood haemoglobin (Hb) concentration undergoes remarkable changes after the birth. Hb values of 16-17 g/100 ml in the newborn may drop to 10-12 g/100 ml at the age of 2-3 months, after which they gradually increase to the
Received July 17, 1988 Z Kinderchir 45 (1990) 146-147 © Hippokrates Verlag Stuttgart
level of adults. Accordingly, reference values of Hct change during the first months of life. By contrast, mean corpuscular volurne of erythrocytes (MCV) increases slowly from 70J.l3 at the age of three months up to 90J.l3 in older adults (3). As a consequence of these changes together with vascular growth, increase in cardiac output volume and arterial blood pressure Iocal tissue perfusion and oxygen delivery are not only age-dependent but individual and locally different. In cases of operative bleeding and blood transfusion the final effect on WH depends on the amount of blood lass, time lapse before transfusion and storing time of the bank blood. Hence, WH studies in man should be performed individually or in standardised conditions for selected groups of patients, although they are made in connection with routine operations.
Downloaded by: National University of Singapore. Copyrighted material.
Summary
E.ffect ofHaematocrit on Wound Healing in Children
Haematocrit (%) Number of patients Age (yrs) ± sd MA/PMN 48 ± sd MA/M048 ± sd MA/CAC 48 ± sd
35-36
37-38
39
~
15 8.42±2.7 6.21 ± 1.4 13.96± 1.3 9.80± 1.8
20 9.89±3.0 6.58± 1.3 14.87±0.8 10.27 ± 1.6
10 11.93±2.9 6.39±2.4 14.90± 1.4 11.14±2.7
21 10.59±3.1 5.30± 1.9 13.41 ± 1.2 9.33±2.1
Patients and methods From a patient series of 990 children, routinely operated on during a five-year period and studied for WH by the Cellstic device (5), 66 boys, aged from 5 to 15 years, mean 10.1 years, were selected for this study. All of them had an unilateral inguinal hemia but were otherwise healthy both clinically and according to routine laboratory investigations. For all of them hemia operation was performed similarly through a 5 to 7 cm long groin skin incision. Bleeding was minimal and no complications were found in WH. At the end of each operation, before closing the skin wound, one end of a Cellstic drain, composed of standard-sized cellulose spange inside a Silastic® tube, was placed subcutaneously between the wound edges. The Cellstics were removed after 48 hours and the wound ceIls harvested inside the tube were washed out by aretrograde injection technique, cytocentrifuged, and stained with May-Grünwald-Giemsa for differential count of the cells. Transformed mutual ceIl 10 cell ratios were then calculated, from which the speed of WH could be determined.
At the age of 5-15 years transformed ratios of macrophages to polymorphonuclear (PMN) cells at hour 48 (MAlPMN4S )' 10 monocytes (MAlM04S ) and 10 cell aggregation centers (MAlCAC4S ) (6), respectively, were highest, when Hct varied between 37 and 39 % (Table 1), indicating that WH was most advanced in these patients. CorresJ)9nding values of Hb varied between 12.0 and 12.5 g/100 ml. Hct values under and over these limits began to retard WH significantly (p < 0.02) without any visual signs of delay. Comparison of these values with age-adjusted references (3) revealed that both Hct and Hb were below the normal means hut just above the lower limits of normal.
Although all patients in this study healed without any complications their WH was different at the cellular level. This is natural because only after remarkable defects in wound cell population a clinically manifest wound complication will occur. Several factors affect WH coincidentally in seriously sick patients. Therefore it is important to know the role of these factors and to correct them.
References
2
3 4
5 6
7
Goodson WH, Hunt TK: Wound healing and the diabetic patient. Surg Gynecol Obstet 149 (1979) 600-608 Heughan C, Chir B, Grislis G, Hunt TK: The effect of anemia on wound healing. Ann Surg 179 (1974) 163-167 Nathan DG, Oski FA: Hematology of Infancy and Childhood. Vol I. Philadelphia: Saunders 1987. Taylor DEM, Whamond }5, Penhallow JE: Effects of hemorrhage on wound strength and fibroblast function. Sr J Surg 74 (1987) 316-319 Viljanto j: Cellstic: A device for wound healing studies in man. J Surg Res 20 (1976) 115-119 Viljanto j, Rajamäki A, Renvall 5, Raekallio]: Cell aggregation centers initial strength elements in human wound healing. J Surg Res 29 (1980) 414-421 Viljanto j, Savunen T: Prediction of wound tensile strength by the Cellstic device. Abstr. ESSR XXII Congress, Aarhus 1987
}. Viljanto, M. D.
Discussion Wound cell analysis is a reliable indirect method for early evaluation of WH process. Although the cells harvested by the Cellstic device during the first 48 hours after sur-
40
gery reflect the quality and intensity of the inflammatory phase of WH they still are predictive for wound tensile strength two to three weeks forward, as was shown earlier in an experimental study (7). Defects in the inflammatory phase oI healing, especially the elimination of macrophages, directly caused failure of subsequent fibroblast growth and collagen synthesis (1).
1
Results
147
Dept. of Paediatrics Division of Surgery Turku University Central Hospital SF-20520 Turku 52, Finland
Downloaded by: National University of Singapore. Copyrighted material.
Table 1 Transformed mutual ratios of Cellstic cells according to haematocrit values 48 hours after operations.
Z Kinderchir 45 (1990)
