Abstract
Purpose
Trauma centres have been proven to provide better outcomes in developed countries for overall trauma, but there is limited literature on the systematic factors that describe any discrepancies in outcomes for trauma laparotomies in these centres. This study was conducted to examine and interrogate the effect of systematic factors on patients undergoing a trauma laparotomy in a developed country, intending to identify potential discrepancies in the outcome.
Methods
This was a retrospective study of all laparotomies performed for trauma at a level 1 trauma centre in New Zealand. All adult patients who had undergone an index laparotomy for trauma between February 2012 and November 2020 were identified and laparotomies for both blunt and penetrating trauma were included. Repeat laparotomies and trauma laparotomies in children were excluded. The primary clinical outcomes reviewed included morbidity, length of hospital stay, and mortality. All statistical analysis was performed using R v.4.0.3.
Results
During the 9-year study period, 204 trauma laparotomies were performed at Waikato hospital. The majority (83.3%) were performed during office hours (170/204), and the remaining 16.7% were performed after hours (34/204). And 61.3% were performed on a weekday (125/204), whilst 38.7% were performed on the weekend/public holiday (79/204). Most of the parameters in office hours and after hours groups had no statistically significant difference, except lactate (p = 0.026). Most of the variables in weekday and weekend groups had no statistically significant difference, except pH, lactate, length of stay, and gastrointestinal complications (p = 0.012, p < 0.001, p = 0.003, p = 0.020, respectively).
Conclusion
The current trauma system at Waikato hospital is capable of delivering care for trauma laparotomy patients with the same outcome regardless of working hours or after hours, weekday or weekend. This confirms the importance of a robust trauma system capable of responding to the sudden demands placed on it.
Keywords: Wounds and injuries, General surgery, Trauma surgery, Abdominal trauma, Systematic factors
Introduction
Over the past several decades, a large body of literature has emerged documenting the influence of systematic factors on the outcome of emergency laparotomy.1,2 One such factor is a phenomenon known as the “weekend effect”, in which patients who undergo emergency laparotomy outside of regular office hours may have poorer outcomes than those who have the same procedure during working hours.3 Major trauma hospitals should theoretically provide a consistent service and staffing regardless of time or day of admission and should thus be immune to this “weekend effect”.1, 2, 3 Most of the literature focuses on medical or general surgical disciplines, and very little has been written specifically about the outcome of trauma laparotomies.4,5 A trauma laparotomy is an emergency procedure commonly undertaken in less than ideal circumstances by a heterogeneous group of surgeons in terms of seniority, experience, and subspecialty training.6 The surgical principles behind a trauma laparotomy substantially differ from a laparotomy for other surgical emergencies. In that, decisions on haemorrhage control, contamination control, and whether to proceed with definitive management or with an abbreviated procedure are required to be made quickly.6 It is a dynamic procedure with significant potential for poor decision-making and error. If systematic factors are associated with discrepancies in outcome for emergency procedures, it is highly likely that they will also impact the outcome for trauma laparotomy. There is an increasing of interest in quantifying discrepancies in surgical outcomes and attempting to understand why they occur in the hope of addressing them.1 This has never been studied in the trauma population in New Zealand. This study aimed to examine and interrogate the effect of systematic factors on the outcome of patients undergoing trauma laparotomy in a developed country, intending to identify potential discrepancies in the outcome.
Methods
Clinical setting
Waikato hospital is located in Hamilton, New Zealand. It is a tertiary centre and university hospital, with a clinical school affiliated with the University of Auckland. It is one of the largest acute hospitals in the country and is the only Royal Australasian College of Surgeons (RACS) certified level 1 trauma centre in New Zealand. The Waikato District Health Board covers a catchment population of approximately 440,000 people. It manages approximately 3400 trauma admissions per annum, over 400 of which have injury severity score > 12.7 The department of surgery at Waikato hospital is a RACS-designated training centre. The trauma service is provided by a dedicated department of trauma consisting of 2 subspecialist trauma surgeons. In conjunction with the general surgeons, the department provides surgical cover for trauma service 24-h-a-day and 7 days a week.
Study design
The prospectively managed trauma database of the Midland system (an institute that manages trauma protocols and systems in the Waikato region in New Zealand) was retrospectively reviewed, and all adult patients who had undergone an index laparotomy for trauma between January 2012 and December 2020 were identified. Trauma laparotomies in children and repeat laparotomies were excluded. Laparotomies for both blunt and penetrating trauma were included. The case notes and the operative record for each case were reviewed. The primary clinical outcomes reviewed included morbidity, length of hospital stay, and mortality.
For this study, operations during the weekdays (Monday to Friday) and working hours (office hours) were defined as 08:00–22:00. Specialist consultant surgeons are present on-site during these times. During weekdays, outside working hours (after hours) were defined as 22:00–08:00. At these times, the specialist consultant surgeon is not stationed on-site but is available on call for all clinical duties as required. The registrars maintain a 24-h-a-day, 7 days a week in-hospital presence. Over weekends (Saturday and Sunday) and public holidays, there is a specialist presence in the hospital during working hours (08:00–16:00), but after hours (16:00–08:00), the specialists are not on-site. Public holidays are considered as part of the weekend for this study. Institutional ethics was sought and approved by the Clinical Audit Support Unit of the Waikato District Health Board (Reference: 4142).
Statistical analysis
All statistical analysis was performed using R v.4.0.3 (R Foundation for Statistical Computing, Vienna, Austria). The data were stratified into office hours and after hours, weekday and weekend for comparison. Continuous variables were reported as mean ± standard deviation (SD) and compared using the one-way analysis of variance or independent samples Student's t-test. Categorical data were reported as the frequency (n) and percentage (%) and compared using the Chi-squared or Fisher's exact test (when n < 5). A two-tailed p < 0.05 was considered statistically significant.
Results
During the 9-year study period, a total of 237 trauma laparotomies were performed at Waikato hospital. Of which 33 were excluded either due to inadequate documentation (n = 14) or due to not meeting the age criteria for eligibility. A total of 204 trauma patients were ultimately included in the study, of which 82.4% were for blunt trauma, and the remaining 17.6% were for penetrating trauma (5.4% gunshot wounds and 12.2% stab wounds). The majority of laparotomies (83.3%) were performed during office hours (170/204), and the remaining 16.7% were performed after hours (34/204). The number of trauma laparotomies performed during a weekday was 125/204 (61.3%), whilst 79/204 (38.7%) were performed on the weekend/public holiday.
Office hours compared to after hours
A direct comparison was made between trauma laparotomies performed during office hours with those performed during after hours. These differences are summarised in Table 1. The demographics, physiology (other than the lactate), and mechanism of injury were similar in both groups and held no statistical significance. The lactate was marginally higher in the after hours group (3.2 mmol/L) compared to the office hours group (3.1 mmol/L) and reached statistical significance (p = 0.026).
Table 1.
The comparison of variables in office hours group and after hours group.
| Variables | Office hours (n = 170) | After hours (n = 34) | p value |
|---|---|---|---|
| Age (year) | 40 ± 18 | 36 ± 19 | 0.860 |
| Gender | |||
| Male | 107 (62.9) | 25 (73.5) | 0.330 |
| Female | 63 (37.1) | 9 (26.5) | 0.330 |
| Physiology | |||
| Heart rate (beats/min) | 98 ± 26 | 101 ± 25 | 0.770 |
| Systolic blood pressure (mmHg) | 111 ± 28 | 107 ± 31 | 0.340 |
| Shock index | 1 ± 0.5 | 1.0 ± 0.4 | 0.940 |
| pH | 7.29 ± 0.11 | 7.28 ± 0.12 | 0.450 |
| Lactate (mmol/L) | 3.1 ± 2.4 | 3.2 ± 2.1 | 0.026∗ |
| Base excess | −3.7 ± 4.9 | −4.5 ± 4.6 | 0.210 |
| Mechanism | |||
| Penetrating | 30 (17.6) | 6 (17.6) | 1.000 |
| Blunt | 140 (82.4) | 28 (82.4) | 1.000 |
| Consultant at operation | |||
| Yes | 130 (76.5) | 30 (88.2) | 0.200 |
| No | 40 (23.5) | 4 (11.8) | |
| Outcomes | |||
| Length of stay (days) | 19 ± 25 | 18 ± 14 | 0.200 |
| Complication | 60 (35.3) | 15 (44.1) | 0.440 |
| Survived | 162 (95.3) | 31 (91.2) | 0.400 |
| Died | 8 (4.7) | 3 (8.8) | 0.400 |
∗ p < 0.05, means statistically significant.
Data presented as mean ± SD or n (%).
The rate of consultant presence, mortality rate, complication rate, and mean length of stay was similar in both groups and held no statistical significance.
Weekday compared to weekend
A direct comparison was made between trauma laparotomies performed on weekdays and on the weekends during the study period. This is summarised in Table 2. The demographics, physiology, mechanism of injury, and the rate of consultant presence were similar between the 2 groups and had no significance. However, the pH was marginally lower in the weekday group (7.28) compared to the weekend group (7.29) (p = 0.012). The lactate was also marginally higher in the weekday group (3.2 mmol/L) compared to the weekend group (3.0 mmol/L) (p < 0.000). The mean length of stay was higher in the weekend/public holiday group (20 days) compared to the weekday group (18 days) and reached statistical significance (p = 0.003). Otherwise, both groups' mortality and complication rates (excepted gastrointestinal complications) were similar and had no statistical significance. The weekday group had a higher rate of gastrointestinal complications compared to the weekend group (21% vs. 8%, p = 0.020) and reached statistical significance. Regarding mortality, 5 deaths occurred in the weekday cohort and 6 in the weekend cohort. The causes of death in the weekday group were as follows: 1 case of cardiac arrest, 2 of brain death, and 2 of multi-organ failure. The causes of the weekend group were as follows: 2 cases of exsanguination, 2 of multi-organ failure, 1 of cardiac arrest, and 1 of brain death.
Table 2.
The comparison of variables in weekday group and weekend group.
| Variables | Weekday (n = 125) | Weekend (n = 79) | p value |
|---|---|---|---|
| Age (year) | 39 ± 18 | 39 ± 18 | 0.670 |
| Gender | |||
| Male | 79 (63.2) | 53 (67.1) | 0.680 |
| Female | 46 (36.8) | 26 (32.9) | 0.680 |
| Physiology | |||
| Heart rate (beats/min) | 97 ± 25 | 100 ± 26 | 0.250 |
| Systolic blood pressure (mmHg) | 108 ± 28 | 113 ± 30 | 0.560 |
| Shock index | 1 ± 0.5 | 1.0 ± 0.5 | 0.190 |
| pH | 7.28 ± 0.11 | 7.29 ± 0.11 | 0.012∗ |
| Lactate (mmol/L) | 3.2 ± 2.4 | 3.0 ± 2.3 | <0.001∗ |
| Base excess | −4.7 ± 4.9 | −3.9 ± 4.6 | 0.260 |
| Mechanism | |||
| Penetrating | 23 (18.4) | 13 (16.5) | 0.870 |
| Blunt | 102 (81.6) | 66 (83.5) | |
| Consultant at operation | |||
| Yes | 96 (76.8) | 64 (81.0) | 0.590 |
| No | 29 (23.2) | 15 (19.0) | |
| Outcomes | |||
| Length of stay (days) | 18 ± 17 | 20 ± 31 | 0.003∗ |
| Complication | 49 (39.2) | 26 (32.9) | 0.450 |
| Anastomotic leak | 3 (2.4) | 0 (0) | |
| Respiratory | 11 (8.8) | 11 (13.9) | 0.360 |
| Wound | 11 (8.8) | 8 (10.1) | 0.940 |
| Renal | 4 (3.2) | 2 (2.5) | 0.880 |
| Cardiac | 6 (4.8) | 4 (5.1) | 0.800 |
| Gastrointestinal | 26 (20.8) | 6 (7.6) | 0.020∗ |
| Other | 9 (7.2) | 5 (6.3) | 0.964 |
| Survived | 120 (96.0) | 73 (92.4) | 0.340 |
| Died | 5 (4.0) | 6 (7.6) | |
∗ p < 0.05, means statistically significant.
Data presented as mean ± SD or n (%).
Discussion
There is a significant body of literature highlighting the issue of discrepancies in health outcomes secondary to systematic factors such as the time of hospital admission and time of surgery.1,2,4,5,8 One of the most commonly cited factors is the so-called “weekend effect”, a phenomenon in which patients admitted to the hospital over the weekend have comparatively worse outcomes than those admitted during the weekdays.3,4 Similarly, emergency operations undertaken after hours have been suggested to have comparatively inferior outcomes to those performed during working hours.9 The concept of a “weekend effect” has been the focus of major debate in the United Kingdom for many years.10 A systematic review by Honeyford et al.3 noted that despite the high levels of heterogeneity of the published literature to date, the “weekend effect” was noted even after accounting for the severity of the disease. Several possible explanations for the “weekend effect” have been proposed. Patients admitted on the weekend are often more ill than those admitted during working hours, and thus outcomes are likely to be worse.11,12 Staffing levels, in general, are relatively lower on weekend, and hence there are delays in imaging and accessing surgery.13 The counterargument is that this is not a real phenomenon but a statistical artefact.14 The controversy in the United Kingdom has developed into a major political dispute between junior doctor activists, academics, and the department of health over staffing issues and work hours.15
In the literature, medical or general surgical disciplines have been the focus of these debates. Much less is known about the “weekend effect” as it relates to trauma surgery.1, 2, 3, 4, 5 Trauma is a time-sensitive pathology. Those requiring emergency laparotomy are already a vulnerable group that commonly present after hours when staffing levels at health care facilities are generally lower.16 Health care managers must ensure that these already vulnerable patients are not victims of a “double jeopardy” effect compounded by the influence of systematic factors. Given that trauma laparotomy is an emergency procedure, there may be heterogeneous staff caring for these patients and varying levels of physical resources available to meet the demand. However, a study by Carr et al.17 from the United States noted that differential mortality related to after-hours surgery is not seen in their level 1 trauma centre. This may reflect the structure of a North American level 1 centre, which is mandated to be appropriately staffed and operational at all times. Other studies from both the United States and the United Kingdom also demonstrate comparable mortality among injured patients presenting on weeknights in comparison to weekdays. It appears that robust trauma systems attenuate and are protective against the “weekend effect”.18,19 The response to trauma is a systematic one. This has long been recognised and promoted by the American college of surgeons. The American college of surgeons has a robust accreditation process for trauma centres.20 A similar process has been in place in New Zealand, and our institution is the only RACS accredited level 1 trauma centre in the country.21 Our study is the first in New Zealand to review the “weekend effect” phenomenon and specifically focus on the subset of trauma patients requiring emergency laparotomy for trauma. Our study has not shown a significant variation in outcome. This suggests that the current trauma system at Waikato hospital is sufficiently robust and capable of delivering equitable levels of trauma care irrespective of whether the patient presents after or during working hours. One of the complexities of developing a robust trauma system is that it needs a degree of flexibility, which will allow it to expand to meet unexpected demands as appropriate. The initial phase of establishing a trauma system can be difficult. There are limitations in resources which need to be addressed. Prioritisation and appropriate allocation of resources are crucial. Our centre is the central hospital which covers a total of 5 separate hospitals, allowing appropriate resources to be allocated. This focused allocation of resources enabled Waikato hospital to become a dedicated trauma service.
The limitations of our studies include but are not limited to the retrospective nature of the study, the proportionately low rates of penetrating trauma, and systematic differences such as a 24/7 on-call surgeon. The study is based on a single-centre and may limit the generalisability of the results. Therefore, future multi-institutional studies will help inform the readers further on this topic.
The current trauma system at Waikato hospital trauma patients is capable of delivering care for trauma laparotomy patients with the same outcome regardless of work hours or day of the week. This confirms the importance of a robust trauma system capable of responding to the sudden demands placed on it.
Funding
Nil.
Ethical statement
Institutional ethics was sought and approved by the Clinical Audit Support Unit (CASU) of the Waikato District Health Board (Reference: 4142).
Declaration of competing interest
The authors have no conflicts of interest to declare.
Author contributions
Jonathan Ko, Victor Kong, Janet Amey, Damien Ah Yen, Damian Clarke, and Grant Christey were all involved in the drafting of the manuscript, review and approval of the published version, design, analysis, and interpretation of the data used for the study.
Footnotes
Peer review under responsibility of Chinese Medical Association.
References
- 1.Oliver C.M., Bassett M.G., Poulton T.E., et al. Organisational factors and mortality after an emergency laparotomy: multilevel analysis of 39 903 National Emergency Laparotomy Audit patients. Br J Anaesth. 2018;121:1346–1356. doi: 10.1016/j.bja.2018.07.040. [DOI] [PubMed] [Google Scholar]
- 2.Nugent E., O'Connell E., Ooi E., et al. Impact of service delivery factors on patient outcomes in emergency general surgery. Surgeon. 2021;19:156–161. doi: 10.1016/j.surge.2020.04.005. [DOI] [PubMed] [Google Scholar]
- 3.Honeyford K., Cecil E., Lo M., et al. The weekend effect: does hospital mortality differ by day of the week? A systematic review and meta-analysis. BMC Health Serv Res. 2018;18:870. doi: 10.1186/s12913-018-3688-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Freemantle N., Richardson M., Wood J., et al. Weekend hospitalization and additional risk of death: an analysis of inpatient data. J R Soc Med. 2012;105:74–84. doi: 10.1258/jrsm.2012.120009. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Hoehn R.S., Go D.E., Dhar V.K., et al. Understanding the "weekend effect" for emergency general surgery. J Gastrointest Surg. 2018;22:321–328. doi: 10.1007/s11605-017-3592-x. [DOI] [PubMed] [Google Scholar]
- 6.Maclean W., Levy B., Rockall T. Trauma laparotomy and damage control surgery. Surgery. 2019;37:549–557. doi: 10.1016/j.mpsur.2019.07.014. [DOI] [Google Scholar]
- 7.Midland Trauma System Midland trauma system Annual Report 2019 PDF on Internet. Hamilton (NZ), Midland trauma system. 2019. https://www.midlandtrauma.nz/wp-content/uploads/2020/11/MTS-Midland-Trauma-System-annual-report-2019_web.pdf
- 8.Cortegiani A., Ippolito M., Misseri G., et al. Association between night/after-hours surgery and mortality: a systematic review and meta-analysis. Br J Anaesth. 2020;124:623–637. doi: 10.1016/j.bja.2020.01.019. [DOI] [PubMed] [Google Scholar]
- 9.Zapf M.A., Kothari A.N., Markossian T., et al. The "weekend effect" in urgent general operative procedures. Surgery. 2015;158:508–514. doi: 10.1016/j.surg.2015.02.024. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Torjesen I. Academic calls for MPs to investigate "weekend effect" in view of conflicting evidence. BMJ. 2016;353:i2667. doi: 10.1136/bmj.i2667. [DOI] [PubMed] [Google Scholar]
- 11.Freemantle N., Ray D., McNulty D., et al. Increased mortality associated with weekend hospital admission: a case for expanded seven day services? BMJ. 2015;351:h4596. doi: 10.1136/bmj.h4596. [DOI] [PubMed] [Google Scholar]
- 12.Walicka M., Tuszyńska A., Chlebus M., et al. Predictors of in-hospital mortality in surgical Wards: a Multivariable retrospective cohort analysis of 2,800,069 Hospitalizations. World J Surg. 2021;45:480–487. doi: 10.1007/s00268-020-05841-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Freemantle N., Richardson M., Wood J., et al. Weekend hospitalization and additional risk of death: an analysis of inpatient data. J R Soc Med. 2012;105:74–84. doi: 10.1258/jrsm.2012.120009. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Meacock R., Anselmi L., Kristensen S.R., et al. Higher mortality rates amongst emergency patients admitted to hospital at weekends reflect a lower probability of admission. J Health Serv Res Pol. 2017;22:12–19. doi: 10.1177/1355819616649630. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Wise J. Higher weekend death rate is flawed, study finds. BMJ. 2016;353:i2598. doi: 10.1136/bmj.i2598. [DOI] [PubMed] [Google Scholar]
- 16.Carmody I.C., Romero J., Velmahos G.C. Day for night: should we staff a trauma center like a nightclub? Am Surg. 2002;68:1048–1051. [PubMed] [Google Scholar]
- 17.Carr B.G., Jenkins P., Branas C.C., et al. Does the trauma system protect against the weekend effect? J Trauma. 2010;69:1042–1047. doi: 10.1097/TA.0b013e3181f6f958. ; discussion 1047-1048. [DOI] [PubMed] [Google Scholar]
- 18.Metcalfe D., Perry D.C., Bouamra O., et al. Is there a 'weekend effect' in major trauma? Emerg Med J. 2016;33:836–842. doi: 10.1136/emermed-2016-206049. [DOI] [PubMed] [Google Scholar]
- 19.Dvorak J.E., Lester E.L.W., Maluso P.J., et al. There is No weekend effect in the trauma patient. J Surg Res. 2021;258:195–199. doi: 10.1016/j.jss.2020.08.065. [DOI] [PubMed] [Google Scholar]
- 20.American College of Surgeons . sixth ed. PDF on Internet. Chicago (IL): American College of Surgeons, Committee on Trauma; 2014. Resources for Optimal Care of the Injured Patient.https://www.facs.org/-/media/files/quality-programs/trauma/vrc-resources/resources-for-optimal-care.ashx [Google Scholar]
- 21.Midland Trauma System . Midland Trauma System; Hamilton (NZ): 2019. Waikato Hospital Achieves Level 1 Trauma Verification – First for New Zealand Internet.https://www.midlandtrauma.nz/waikato-hospital-achieves-level-1-trauma-verification-a-first-for-new-zealand/ [Google Scholar]