Table 8.
Univariable Analysis of Risk Factors for Related Infection at Thirty Days
| |
Patients without a related infection (n = 210) |
Patients with a related infection (n = 55) |
|
|
||
|---|---|---|---|---|---|---|
| Factor |
Number or value |
% |
Value |
% |
p
a
|
Odds ratiob |
| Demographic factors | ||||||
| Age (mean ± SD) | 33.8 ± 14.1 | 29.8 ± 10.2 | 0.042 | 0.97 (0.95–0.99) | ||
| Male Gender | 182 | 86.7 | 49 | 89.1 | 0.632 | 1.26 (0.52–3.51) |
| Race (African American) | 140 | 66.7 | 46 | 83.6 | 0.014 | 2.56 (1.23–5.85) |
| Weight (kg) [mean ± SD] | 80.7 ± 18.0 | 84.6 ± 21.5 | 0.171 | 1.01 (0.99–1.03) | ||
| Median Income of home zip code: | ||||||
| <50% | 41 | 19.5 | 14 | 25.5 | 0.234 | Reference |
| 50%–100% | 104 | 49.5 | 30 | 54.6 | 0.551 | 0.85 (0.41–1.79) |
| >100% | 65 | 31.0 | 11 | 20.0 | 0.100 | 0.50 (0.20–1.03) |
| Transfer patient | 55 | 26.2 | 8 | 14.6 | 0.071 | 0.48 (0.20–1.03) |
| Medical comorbidities | ||||||
|---|---|---|---|---|---|---|
| Any significant medical comorbidity | 130 | 61.9 | 33 | 60.0 | 0.796 | 0.92 (0.51–1.71) |
| More than one medical comorbidity | 58 | 27.6 | 12 | 21.8 | 0.385 | 0.73 (0.35–6.29) |
| Blood alcohol level >80 mg/dL | 45 (n = 177) | 25.4 | 10 (n = 48) | 20.8 | 0.512 | 0.77 (0.34–1.63) |
| Urine drug screen positive for amphetamines, barbiturates, cocaine, or non-medicinal opioids | 15 (n = 99) | 15.2 | 8 (n = 27) | 29.6 | 0.084 | 2.36 (0.85–6.29) |
| Prior abdominal surgery | 30 | 14.3 | 8 | 14.6 | 0.961 | 1.02 (0.41–2.28) |
| Mechanism of injury | ||||||
|---|---|---|---|---|---|---|
| Penetrating versus blunt | 154 | 73.3 | 48 | 87.3 | 0.031 | 2.49 (1.13–6.32) |
| Mechanism of Injury: | ||||||
| Gunshot injury | 111 | 52.9 | 38 | 69.1 | 0.049 | Reference |
| Stabbing or other penetrating injury | 43 | 20.5 | 10 | 18.2 | 0.754 | 0.68 (0.30–1.44) |
| Motor vehicle injury | 47 | 22.4 | 5 | 9.1 | 0.027 | 0.31 (0.10–0.77) |
| Other blunt injury | 9 | 4.3 | 2 | 3.6 | 0.915 | 0.65 (0.10–2.66) |
| Severity of injury | ||||||
|---|---|---|---|---|---|---|
| Median overall ISS [IQR] | 16 (n = 205) | 24.5 (n = 54) | 0.041 | 1.03 (1.001–1.05) | ||
| [9 – 25] | [10–26] | |||||
| Median abdominal ISS [IQR] | 3.0 (n = 205) | 3.5 (n = 54) | 0.001 | 1.52 (1.17–2.03) | ||
| [2 – 4] | [3 – 4] | |||||
| Probability of survival (mean ± SD) | 0.902 ± 0.231 (n = 202) | 0.895 ± 0.205 (n = 53) | 0.841 | 0.87 (0.26–3.69) | ||
| Initial lactate concentration (mmol/L) [mean ± SD] | 4.6 ± 3.0 (n = 86) | 5.7 ± 4.2 (n = 17) | 0.201 | 1.10 (0.94–1.27) | ||
| Initial lactate concentration ≥2.2 mmol/L | 71 (n = 86) | 82.6 | 13 (n = 17) | 76.5 | 0.554 | 1.46 (0.37–4.8) |
| Concomitant injuries | ||||||
|---|---|---|---|---|---|---|
| Any chest injury | 86 | 41.0 | 20 | 36.4 | 0.536 | 0.82 (0.44–1.51) |
| Any pelvic fracture | 49 | 23.3 | 9 | 16.4 | 0.266 | 0.64 (0.28–1.35) |
| Major spine or spinal cord Injury (excluding spinous/transverse process fractures) | 27 | 12.9 | 10 | 18.2 | 0.311 | 1.51 (0.65–3.26) |
| Fracture or major soft tissue extremity injury | 60 | 28.6 | 15 | 27.3 | 0.849 | 0.94 (047–1.79) |
| Extra-abdominal vascular injury | 9 | 4.3 | 7 | 12.7 | 0.019 | 3.26 (1.11–9.18) |
| Any extra-abdominal injury | 148 | 70.5 | 41 | 74.6 | 0.553 | 1.23 (0.64–2.48) |
| Timing of laparotomy | ||||||
|---|---|---|---|---|---|---|
| Median time in ED (min) [IQR] | 46 | 29 | 0.379 | 0.99 (0.98–1.02) | ||
| [27–93] | [18–55] | |||||
| Median time from injury to operation (min) [IQR] | 130 | 72 | 0.117 | 0.99 (0.99–1.00) | ||
| [81–249] | [59–125] | |||||
| Details of initial laparotomy | ||||||
|---|---|---|---|---|---|---|
| Negative laparotomy (no abdominal injury encountered) | 10 | 4.8 | 2 | 3.6 | 0.721 | 0.76 (0.11–2.97) |
| Non-therapeutic laparotomy (no abdominal injury treated during laparotomy) | 24 | 11.4 | 3 | 5.5 | 0.192 | 0.45 (0.10–1.35) |
| Any gastrointestinal tract injury | 94 | 44.8 | 42 | 76.4 | <0.001 | 3.99 (2.07–8.13) |
| Any colon and/or rectal injury | 50 | 23.8 | 31 | 56.4 | <0.001 | 4.13 (2.23–7.76) |
| Median number of units of PRBCs transfused [IQR] | 0 | 1 | <0.001 | 1.07 (1.03–1.12) | ||
| [0–4] | [0–9] | |||||
| Any pre-operative or intra-operative PRBC transfusion | 97 | 46.2 | 32 | 58.1 | 0.113 | 1.62 (0.89–2.98) |
| Transfusion of ≥10 units of PRBCs (pre-operative and intra-operative) | 16 | 7.6 | 13 | 23.6 | 0.001 | 3.75 (1.66–8.39) |
| Duration of laparotomy (min) (mean ± SD) | 123.6 ± 63.5 | 146.2 ± 67.0 | 0.028 | 1.005 (1.001–1.009) | ||
| Concomitant extra-abdominal procedure | 20 | 9.5 | 7 | 12.7 | 0.496 | 1.39 (0.52–3.33) |
| Abdominal fascia left open at end of initial laparotomy | 37 | 17.6 | 21 | 38.2 | 0.001 | 2.89 (1.50–5.52) |
| Subsequent management | ||||||
|---|---|---|---|---|---|---|
| Post-operative ICU destination | 117 | 55.7 | 37 | 67.3 | 0.122 | 1.63 (0.88–3.11) |
| Subsequent abdominal procedure | 44 | 21.0 | 26 | 47.3 | <0.001 | 3.38 (1.81–6.34) |
| Subsequent extra-abdominal procedure | 48 | 22.9 | 24 | 43.6 | 0.003 | 2.61 (1.40–4.87) |
| Median days abdominal fascia left open [IQR) | 2 (n = 37) | 3 (n = 21) | 0.004 | 1.23 (1.08–1.44) | ||
| [1-4] | [2-13] | |||||
| Skin left open after final abdominal procedure | 82 | 39.1 | 35 | 63.6 | 0.001 | 2.73 (1.49–5.13) |
| Post-operative use of vasopressors for >6 h | 18 | 8.6 | 7 | 12.7 | 0.348 | 1.56 (0.58–3.98) |
| Compliance with measures of appropriate antibiotic use | ||||||
|---|---|---|---|---|---|---|
| Pre- versus post-intervention cohort: | ||||||
| Pre-intervention | 102 | 48.6 | 37 | 67.3 | 0.013 | 0.46 (0.24–0.85) |
| Post-intervention | 108 | 51.4 | 18 | 32.7 | ||
| Compliant with all measures | 123 | 58.6 | 22 | 40.0 | 0.014 | 0.47 (0.26–0.86) |
| Timely delivery of initial antibiotic dose | 174 | 82.8 | 41 | 74.6 | 0.161 | 0.61 (0.30–1.26) |
| Any antibiotic administered for laparotomy | 195 | 92.9 | 50 | 0–0.9 | 0.626 | 1.30 (0.41–3.54) |
| Initial dose correctly timed | 174 (n = 195) | 89.2 | 41 (n = 50) | 82.0 | 0.164 | 0.55 (0.24–1.34) |
| Correct dosage given | 17 (n = 25) | 68.0 | 9 (n = 9) | 100 | 0.077 | Not calculable |
| Adequate antibiotic spectrum | 28 (n = 46) | 60.9 | 4 (n = 12) | 33.3 | 0.088 | 0.32 (0.08–1.18) |
| Re-dosing for length of procedure | 3 (n = 35) | 8.6 | 0 (n = 15) | 0 | 0.136 | Not calculable |
| Re-dosing for large blood loss | 3 (n = 5) | 60.0 | 1 (n = 7) | 14.3 | 0.222 | 0.11 (0.004–1.43) |
| No extra pre-operative antibiotic agents administered | 170 | 80.9 | 41 | 74.5 | 0.294 | 0.69 (0.35–1.42) |
| Post-operative antibiotic agents discontinued within 24 h | 179 | 85.2 | 40 | 72.7 | 0.029 | 0.46 (0.23–0.95) |
| No post-operative antibiotic agents given | 103 | 49.0 | 14 | 25.5 | 0.002 | 0.36 (0.18–0.68) |
| Prophylactic antibiotic administered | ||||||
|---|---|---|---|---|---|---|
| Cefoxitin | 73 | 34.8 | 24 | 43.6 | 0.224 | 1.45 (0.79–2.65) |
| Cefotetan | 8 | 3.8 | 3 | 5.5 | 0.598 | 1.46 (0.31–5.24) |
| Cefazolin ± metronidazole | 43 | 20.5 | 12 | 21.8 | 0.827 | 1.08 (0.51–2.18) |
| Any cephalosporin | 124 | 59.1 | 39 | 70.9 | 0.108 | 1.69 (0.90–3.29) |
| Ertapenem | 65 | 31.0 | 9 | 16.4 | 0.032 | 0.44 (0.19–0.91) |
| Other antibiotics | 6c | 2.9 | 2d | 3.6 | 0.764 | 1.28 (0.18–5.75) |
SD = standard deviation; ISS = Injury Severity Score ; IQR = interquartile range; ED = emergency department; PRBCs = packed red blood cells; ICU = intensive care unit.
a
For categorical factors with more than two subgroups, a global p value was presented for the relation between the factor and outcome; individual p values are presented for each odds ratio.
b
Odds ratio with 95% confidence interval was presented to measure the odds of having infection of the subgroup compared with the reference group, or the odds of having infection per one unit increase of the numeric factor.
c
Ampicillin/sulbactam, 1; piperacillin/tazobactam, 2; ciprofloxacin + metronidazole or clindamycin, 3.
d
Piperacillin/tazobactam, 2.