Infections in severely traumatized children

Infections

in Severely Traumatized

By Louis M. Bell, M. Douglas

Children

Baker, Dennis Beatty, and Lesli Taylor

Philadelphia, Pennsylvania l To study the incidence and types of infection among severely traumatized children, we reviewed the medical charts of 212 children, hospitalized following traumatic injury, who received antibiotics at sometime during their hospitalization. Infection occurred in 19%. Eleven children had trauma-related infections, whereas 29 (71% of those infected) had 36 nosocomial infections. Tracheitis, sepsis, and urinary tract infections were the most common nosocomial infections and were diagnosed in the second week (10 f 3 days) following injury. Nosocomial infections were more likely to develop in children who were more severely injured and who had a greater number of invasive procedures. Severe head injury (cerebral edema or subarachnoid hemorrhage) was more common in those with nosocomial infection (P < .0002, odds ratio 6.6, 95% confidence interval 2.2 to 21.3). Those without these injuries were much less likely to develop nosocomial infections (specificity 97% and negative predictive value 86%). Finally, the development of any nosocomial infection prolonged the hospitalization by a mean of 16 f 6 days when comparing children with the same degree of traumatic injury. Prevention of nosocomial infection in children with severe trauma will significantly reduce length of hospitalization. Copyright o 1992 by W.B. Saunders Company

INDEX WORDS: Nosocomial head trauma, pediatric.

infection;

trauma,

pediatric;

T

RAUMA IS a leading cause of morbidity and mortality in children, with 25% of traumatic deaths occurring in children each year.l Infections following severe traumatic injury continue to be the leading cause of late nonneurological mortality among adults.2 In adult patients, nosocomial infection rates following traumatic injury have been reported to range from 16% to 80% depending on the severity of injury and need for intensive care.3 Although published reports concerned specifically with the epidemiology of infection in adult trauma patients are available,4-6 the incidence and types of infections among injured children have not been characterized. Furthermore, the infections seen in

adult patients may not be representative of those in children. Patterns of traumatic injury in children differ from those in adults. The child’s proportionately large head relative to body mass, muscular immaturity, and compliant chest wall lead to increased rates of head trauma and blunt injuries to the chest and abdomen.’ Subsequently, infectious complications and/or considerations for the use of presumptive antibiotics may be different than for adults. The purpose of the current study is to determine the incidence of infection among severely traumatized children and to characterize the infections by type (nosocomial or trauma-related), body site, and infecting organism. By comparing the injuries of those children with nosocomial infection with those without, the types of traumatic injury associated with infection and the impact of nosocomial infections on length of hospitalization will be determined. MATERIALS

AND METHODS

Patient Selection The Children’s Hospital of Philadelphia has been a statedesignated level I pediatric trauma center since August 1986. As a result, severely injured children within a broad catchment area are preferentially transported to The Children’s Hospital of Philadelphia for evaluation, and, if hospitalized, are admitted to the Trauma Service. The medical records of children admitted to The Children’s Hospital of Philadelphia trauma service between August 1986 and January 1990 were considered for review. Charts were selected for review if the injured patient was < 18 years of age, had an Injury Severity Score (ISS) of 29, and received antibiotics at some time during the hospitalization. Charts were examined and detailed demographic and historical information was collected, as well as mechanism of injury, vital signs, laboratory studies performed, types of invasive procedures performed, antibiotic use, and infectious complications as defined below. The ISS,’ Glasgow Coma Score (GCS),s and Trauma Score (TS)” were determined for all children enrolled in the study.

Identification and Definition of Infection From the Divisions of General Pediattics and Infectious Diseases, Department of Pediattics, and the Department of Surgery, The Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA. Date accepted: August 6, 1991. Supported in part by the Trauma Program of The ChildrenS Hospital of Philadelphia. Address reprint requests to Louis M. Bell, MD, Division of Infectious Diseases, The Children S Hospital of Philadelphia, 34th St and Civic Center Blvd, Philadelphia, PA 19104. Copyright o 1992 by U?B. Saunders Company 0022-3468/92/2711-0006$03.OOiO 1394

The children enrolled in the study were considered to be infected if a potentially pathogenic organism was isolated from a normally sterile body site or body fluid and if the clinical radiographic and laboratory evidence supported the diagnosis. A urinary tract infection (UTI) was defined as growth of one or two known urinary tract pathogens of 2 100,000 colony forming units per milliliter (cfu/mL) for specimens obtained by the clean-catch method or 21,000 cfu/mL for specimens obtained by urethral catheterization. Catheter-associated sepsis was diagnosed in the child with a new onset of fever and a positive catheter line culture with a potential pathogen. The diagnosis of tracheitis was considered if the child had a fever > 38.4”C and an increase in the amount and change in the character of secretions and either an absolute

JournalofPediatric

Surgery, Vol 27, No 11 (November), 1992: pp 1394-1398

INFECTIONS IN TRAUMATIZED

1395

CHILDREN

increase in peripheral WBC of 20% or more or an increase in the number of polymorphonucleocytes on Gram stain of tracheal secretions. The predominant organism(s) cultured are recorded as pathogens in these cases. The child was considered to have pneumonia with symptoms of fever > 38.4”C and new, nonmigratory infiltrate and tachypnea. A wound infection was defined as the development of erythema, tenderness, induration, warmth, and/or purulent drainage > 2 cm from the wound. There were a total of eight children with otitis media, sinusitis, or prolonged fever of unknown origin who were not included in the analysis because pathogens were not isolated. Nosocomial infections were defined as those infections that developed in hospitalized patients in whom the infection was neither present nor incubating at the time of admission. A trauma-related infection was defined as an infection that developed at the site of injury with the predominant bacteria considered to be a soil or body flora colonizing organism usually via direct inoculation or contiguous spread. Finally, a presumptive antibiotic was defined as the antibiotic(s) given within the first day following injury to children with no clinical or bacteriologic evidence of infection.

Statistical Analysis Chi-square analysis. the Mann-Whitney test, and the Student’s t test were used for analysis of categorical data, rank order, and continuous data, respectively. Odds ratios (OR) with 95% confidence intervals (CI) were also calculated for specific variables. P values ~0.05 were considered significant. Control groups in the case control analyses were selected from the cohort of patients whose charts were reviewed.

RESULTS

There were 451 children with an ISS 2 9 admitted to the hospital during the study period. Of those, 440 (98%) charts were available for review to determine if antibiotics were administered at any time during admission. Two hundred twelve of the children receiving antibiotics at some time during their admission to the hospital comprised the study group. The average age of the group was 7.8 + 5.2 years. Sixty-eight percent were male. The three most common mechanisms of injury were motor vehicle crashes in 55%, falls in 13%, and child abuse in 9%. Seventy children (33%) required tracheal intubation. Seventy-three percent of children were discharged to home after an average hospital stay of 11.5 k 11.8 days. Forty children (19%) required in-patient care at a rehabilitation unit, and 17 (8%) died. Documented infection occurred in 40 children, which comprises 18.9% of the study group and 8.9% of all children with ISS 2 9 requiring hospitalization during the study period. Twenty-nine (13.7%) children in the study group were judged to have nosocomial infections. Eleven (5.2%) children had traumarelated infections. One child had both a nosocomially acquired and trauma-related infection. Eleven children had 11 trauma-related infections (Table 1). Open extremity fractures and blunt abdominal injuries were the most common types of injuries

Table 1. Trauma-Related

Infections in 11 Children

With Severe Trauma Mean Day of Location

No. of

of InfectKJn

Infections

Central nervous sys-

1

Type of

Positive Culture

IIljWV

After Injury

Penetrating head

tern

1

trauma

Extremity (wound)

6

Open fracture in 5,

2

laceration in 1 lntraabdominal

4

Blunt abdominal in-

2

jury Total

11

in this group. The bacteria isolated were either soil organisms or endogenous flora. The cultures were positive within the first or second day following injury. Bacteria isolated from this group are listed in Table 2. Twenty-nine children had 36 nosocomial infections (Table 3). Seven children had more than one nosocomial infections during their hospitalization. Tracheitis (n = 12 patients), sepsis (n = 6), and UTIs (n = 7) were the most common infections. Eleven of 12 children with tracheitis had suffered closed head injuries with abnormalities on computerized axial tomography (CAT) scanning. All children with sepsis had central lines (n = 4) and/or arterial lines (n = 1) in place at the time of their infection. Gram-negative bacteria were isolated in 24 infections, gram positivebacteria in 11 infections, and fungal organisms in three cases (two of line-associated sepsis and one urinary tract infection; Table 3). One child developed pneumonia secondary to respiratory syncytial virus acquired in the hospital. Table 2. Pathogens Isolated From 40 Children With Infections Following Injury

Organisms

Nosocomial

Trauma-Related

Infection*

lnfactionst

Coagulase-positive Staphylococcus

7

Coagulase-negative

2

1

Other gram-positive cocci

2

2

Escherichia

6

3

Staphylococcus

coli

1

Klebsiella species

1

2

Enterobacter

species

2

4

Haemophilus

influenzae

4

Proteus species

1

0

Pseudomonas

6

0

Other gram-negative rods

4

0

Fungal

3

0

Viral (respiratory syncytial virus)

1

0

39

14

species

Anaerobic bacteria

Tota I

1

*Two children with extremity trauma and wound infections had two organisms isolated; both had a Pseudomonas

species and an addi-

tional gram-negative rod isolated. tFour children in this group had two organisms isolated, two each with open fractures and peritonitis.

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BELL ET AL

Table 3. Nosocomial Infections in 29 Children With Severe Trauma

Locationof Infection Upper respiratory (tracheitis)

Mean Day of PositiveCulture

No. of Infections 12

Type of Injury

After Injury

Closed head injury (5) Multiple injuries (6)

9.3

Isolated chest injury (1) Urinary tract

7

Femur fracture (1) Pelvic fracture (1)

7.3

Multiple injuries”(3) Closed head injury (2) Blood (catheter-associated

sepsis)

10

Blunt abdominal injury (2) Closed head injury (3)

Central nervous system

Multiple injuries (4)

Extremity (wound)

Traumatic amputation lower extremity (1)

15.2 9.8

Extremity wound (2) Multiple injury (1) Lower respiratory tract (pneumonia)

2

Closed head injury (2)

Bone (pin tract infection)

1

Multiple injuries (1)

35

Total

7 60

Closed head injury (11) 9.8 ? 3.0t

Multiple injuries (17) Fractures (3) Other (4) *Multiple injuries is defined as head trauma plus abdominal. chest, or extremity injuries. tValue does not include the bone (pin tract infection) infection that occurred at 60 days.

Nosocomial infections developed at variable times during hospitalizations, although the majority were diagnosed with supporting bacterial and fungal cultures during the second week following the injury (Table 3). The mean time of diagnosis was 10 days for nosocomial infections. All but one patient were diagnosed to have nosocomial infections between 7 and 15 days after injury. The single exception was a child who developed a pin tract infection and osteomyelitis with Serratia marcescens at 60 days following the injury. Presumptive antibiotics were used in 11 of 12 patients with trauma-related infections and in 19 (76%) children who subsequently developed nosocomial infections. Among the study group, 185 (87%) children received presumptive antibiotics (ie, antibiotics within 24 hours following injury). The most com-

mon choice of antibiotic was cefazolin prescribed in 148 (70%) children. Oxacillin or penicillin were presumptively used in 46 (22%) other cases. Fiftyseven children (27%) received a second presumptive antibiotic. Among children who did not have a documented infection, 46% (78) received antibiotics for greater than 3 days following injury. In order to determine the types of injuries more commonly associated with nosocomial infections, a control group of 125 children was selected from the study group who were not infected, received presumptive antibiotics, and survived their injuries for more than 3 days. This control group was compared with the group of children with nosocomial infections (Table 4). There were no differences in age, vital signs, or mechanisms of injury between these groups. However, children with nosocomial infections were

Table 4. The Severity of Trauma in 29 Children With Nosocomial Infection Compared with 125 Children Without infection Mean Score or No. With Injury(*SD) Odds Ratio (95% Confidence

Group Nosocomial Group

Without Infection

P Value

Interval)

Injury Severity Score

21 (*lo)

16 (?8)

<.Ol

5 (1.58-8.42)

Glasgow Coma Score

9 (24)

12 (k4)

< ,002

3 (4.63-1.37)

Trauma Score

11 (k4)

13 (+3)

< ,007

Abdominal injury

10 (34%)

18 (14%)

<.03

Upper extremity injury

9 (31%)

17 (14%)

< .05

2.8 (1.0-8.0)

Subarachnoid hemorrhage

7 (24%)

4 (3%)

< .0008

9.6 (2.3-43.5)

10 (34%)

9 (7%)

< .0002

6.8 (2221.3)

Cerebral edema

2 (3.91-,694) 3.1 (1.1-8.5)

NOTE. Children without infection were selected if they: (1) were not infected, (2) received presumptive antibiotics, and (3) survived their injuries for more than 3 days.

INFECTIONS IN TRAUMATIZED

1397

CHILDREN

more severely injured, judging from their ISS, GCS, and TS. The specific injury most associated with the development of a nosocomial infection was head trauma. Evidence of cerebral edema or subarachnoid hemorrhage on CAT scanning had sensitivities of (24% and 35%, respectively), specificities of 93% (95% CI, 87 to 97) and 97% (95% CI, 92 to 99), respectively, and negative predictive values of (86% [95% CI, 80 to 921 and 85% [95% CI, 79 to 911, respectively) for the development of nosocomial infections. Injuries of the neck, chest, or pelvis were not more common in this group. A greater number of invasive procedures were performed among those children with nosocomial infection when compared with the control group described previously. Arterial line placement (P < .0003; OR 4.9; 95% CI, 2.0 to 12.6), urethral catheter placement (P < .003; OR 4.7; 95% CI, 1.6 to 15.2), endotracheal tube placement (P < .004; OR 3.6; 95% CI, 1.5 to 9.1), central line placement (P < .0003; OR 8.9; 95% CI, 2.7 to 30.0), and intracranial pressure catheter placement (P < .OOOOl; OR 7.7; 95% CI, 2.7 to 21.9) were performed significantly more frequently in this group. In a separate analysis in which the severity of injury was controlled for, a control group was selected of children who had severe traumatic injury but did not develop infection. Although all other parameters were similar in both groups, the children with nosocomial infections had significantly longer hospitalizations, as compared to the control group of children who were as severely injured but did not have infection (Table 5). DISCUSSION

These data indicate that infection following severe trauma in children is not an uncommon occurrence. Infection rates in this study population were 9% overall and occurred in 19% of those who received antibiotics. Nosocomial infections were the most frequent type of infection, accounting for 71% of the total. These findings parallel those reported in adult Table 5. Comparison of Length of Hospital Stay in Two Groups With Similar Severity of injury Nosocomial Infection

Control Group (n = 30)’

P Value

Injury Severity Score

20.64 + 9.7

21.3 2 5.4

NS

Glasgow Coma Score

a.75 + 4.4

7.13 2 3.1

NS

Trauma Score

11.6 ‘- 3.5

10.2 + 3.1

NS

Total hospital days

29.1 t 14.1

13.4 + 8.0

(n = 29)

<.0001t

*Control group was selected if they met the following criteria: ISS > 13; total hospital days > 3; GCS < 13; presumptive antibiotics. tDifference

between sample means = 16.0; 95% confidence interval

for this difference is IO to 22.

trauma patients. The Shock Trauma unit at Maryland has reported infection rates of 16%, 80% being nosocomial.5%6 The types of infections in the group of children with nosocomial infections differed in some respects from those reported for adults. These children had comparatively low incidences of bacteremia (14%) or pneumonia (6%) and relatively high incidences of central nervous system infections (11%). In 1981, Caplan and Hoyt reported that of more than 639 infections occurring in adults with multiple traumatic injuries, 40% were associated with bacteremia.5 In addition, 26% of this same group had pneumonia or empyema, whereas only 7% had central nervous system infection. These differences may be related to the types of injuries in children with more blunt injuries, as opposed to penetrating trauma and a higher incidence of head trauma than noted in adult trauma victims.’ The organisms isolated from the group of children were similar to those reported elsewhere.4 The predominance of gram-negative enteric organisms (62% of the pathogens isolated) is expected in hospital acquired infections.” The hospital stay was significantly prolonged in those children with nosocomial infections when the severity of injury was controlled for. The presence of nosocomial infections in our patients was associated with a 16-day (average) prolongation of hospital stay. These findings suggest that prevention of nosocomial infections would, therefore, significantly reduce the length of hospitalization in many patients. While hospital stay was prolonged, mortality secondary to sepsis or infection was not recognized in the group of infected children. The single death in this group occurred in a child with respiratory failure and severe blunt head trauma. Mortality secondary to infection in adults with traumatic injury is higher, with as many as 14% dying of their infection, the majority of which are nosocomially acquired.’ As might be expected, the children who developed nosocomial infections following injury were much more severely injured as reflected in both anatomic GCS and injury-related ISS scoring systems (Table 4). Closely linked to the severity of injury are the numbers of invasive procedures performed, which were also increased in the nosocomially infected group. In this report, children with injuries that resulted in cerebral edema or subarachnoid hemorrhage were more likely to develop nosocomial infections (P < .0002; OR 6.8; 95% CI. 2.2 to 21.3). These are severe injuries, often requiring intensive support and invasive monitoring devices. The poor sensitivity reflects the fact that children without these injuries

1398

BELL ET AL

may certainly develop nosocomial infection. However, the specificity of either cerebral edema (93%) or subarachnoid hemorrhage (97%) along with the good negative predictive value (86% and 85%, respectively) suggests that for children without these injuries nosocomial infections are much less likely to occur. These findings should help to guide the management decisions surrounding antibiotic utilization and the use of infection control measures in these patients. At the time of this study, there was no protocol guiding the use of presumptive antibiotics such as that described by the University of Maryland.5,6 In the present study, 53% of children with ISS > 9 received presumptive antibiotics and 46% received them for more than 3 days. There is some evidence to suggest

that indiscriminate or prolonged use of presumptive antibiotics may predispose patients to nosocomial infections with resistant organisms.‘O Therefore, prospective studies are needed to define more clearly the risks and benefits of presumptive antibiotics in children with severe trauma and to explore ways of minimizing the number of nosocomial infections, such as special infection control measures for patients in intensive care units.”

ACKNOWLEDGMENT The authors are indebted to John M. Templeton, Jr, MD, and Kathy N. Shaw, MD, for their helpful advice and review of the manuscript and to Pat Parkinson for assistance in preparation of the manuscript.

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and treatment of infec-

tions in multiply traumatized patients. Am J Med 79:68-76, 1985 (suppl IA) 7. Baker SP, O’Neill B, Haddon W Jr, et al: The injury severity score: A method for describing patients with multiple injuries and evaluating emergency care. J Trauma 14:187-196, 1974 8. Jennett B, Teasdale G, Galbraith S, et al: Severe head injuries in three countries. J Neurosurg Psychiatry 40:291-298, 1977 9. Champion HR. Sacco WJ, Carnazzo AJ. et al: Trauma Score. Crit Care Med 9:672-676, 1981 10. Allgower M, Durig M, Wolff G: Infection and trauma. Surg Clin North Am 60:133-144,198O 11. Klein BS, Perloff WH. Maki DG: Reduction of nosocomial infection during pediatric intensive care by protective isolation. N Engl J Med 320:1714-1721,1989