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A quality improvement project incorporating preoperative warming to prevent perioperative hypothermia in major burns
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A quality improvement project incorporating preoperative warming to prevent perioperative hypothermia in major burns A.D. Rogers a,b, *, M. Saggaf a,b , N. Ziolkowski a,b a b
Ross Tilley Burn Centre, Sunnybrook Health Sciences Centre, Toronto, Canada Division of Plastic and Reconstructive Surgery, Department of Surgery, University of Toronto, Canada
article info
abstract
Article history:
Background: Patients with extensive burn injuries are susceptible to a host of
Accepted 12 February 2018
accompanying adverse effects should they develop perioperative hypothermia, which
Available online xxx
occurs in up to 1/4 of all major burn cases. This quality improvement project aimed to reduce the incidence of perioperative hypothermia to below 10% of cases in patients
Keywords: Quality improvement Perioperative hypothermia Surgical complications Burn surgery Preoperative warming
with major burn (Total Body Surface Area [TBSA] >15%), within a one year period. Methods: A baseline diagnostic phase was undertaken to provide a greater understanding of the incidence, natural history and risk factors of perioperative hypothermia. We also reviewed and reinforced intraoperative measures in current use, including preemptive adjustment of the ambient temperature, underbody warming mattress use, warming blanket application over areas not operated, regular temperature monitoring, and discussion at the WHO surgical checklist. Preoperative forced air warming with a ‘Bair Hugger’TM was identified as a sound change initiative, a strategy applied to good effect in other surgical settings. The primary outcome measure was the percentage of cases of perioperative hypothermia (<36 C), utilizing a time series design for the period between 1 November 2016 and 31 October 2017. Results: 53 patients with burn greater than 15% TBSA were admitted over the one year period. Of these, 40 patients required 127 operative procedures. Their mean age was 48.23 years, their mean TBSA was 27.65% (range 15–75%), and their mean length of hospital stay was 31.2 days. After the introduction of pre-warming, the proportion of cases of inadvertent hypothermia reduced to 13.77% (n=14/102), with special cause variation, from 24% (n=6/25) in the baseline data collection period. The final temperature correlated with the lowest temperature recorded in only 32% of cases. Based on stakeholder feedback and consensus from the literature, an algorithm was developed which forms the basis for a medical directive for preoperative warming for eligible patients. No significant balancing measures were identified, nor any undue costs incurred. Discussion: The inevitable drop in temperature is ameliorated by sound perioperative practices, rather than just intraoperative ones. This initiative demonstrated the potential benefits of, and motivates for, the broad application of preoperative warming in the context of major acute burn surgery. Further investigations include PDSA cycles to determine whether the duration or degree of intraoperative hypothermia is more virulent. To
* Corresponding author at: D714, Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Toronto, Ontario, M4N 3M5, Canada. E-mail address: [email protected] (A.D. Rogers). https://doi.org/10.1016/j.burns.2018.02.012 0305-4179/© 2018 Elsevier Ltd and ISBI. All rights reserved.
Please cite this article in press as: A.D. Rogers, et al., A quality improvement project incorporating preoperative warming to prevent perioperative hypothermia in major burns, Burns (2018), https://doi.org/10.1016/j.burns.2018.02.012
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consolidate the pre-warming initiative, we have introduced a standard order within our admission order sets to include preoperative warming for all eligible patients. © 2018 Elsevier Ltd and ISBI. All rights reserved.
1.
Background
Burn remains a prominent global health burden, with over 11 million burn injuries requiring medical attention annually, and is a leading cause of traumatic mortality and morbidity [1]. For full thickness and deep partial thickness burns, the widelyaccepted practice, after initial critical care assessment and fluid resuscitation, is early excision and autografting [2–11]. While outcomes are undoubtedly improved because of this approach, early aggressive debridement exposes susceptible patients to the sequelae of hypothermia in the perioperative period [12–14]. A recent review highlighted the scarcity of literature on the sequelae of perioperative hypothermia, and challenged the burn community to “re-evaluate current dogma” regarding surgical principles and practice [12]. Hypothermia, a core temperature under 36 C, is known to have a host of accompanying adverse effects, manifesting as morbid cardiovascular events, infections, a propensity for greater blood loss, prolonged drug metabolism, as well as delays in obtaining definitive wound healing. These, in turn, may necessitate greater periods of mechanical ventilation, antibiotics, inotropes, opiate analgesics, sedatives and blood products, as well as further operative interventions [15–35]. These ill effects have been described in a wide variety of elective and emergency surgical settings, and notably, in the field of trauma surgery [15,16], its inclusion in the ‘lethal triad’ added impetus to ‘damage control’ surgery [36–42]. Even without burn injury, patients undergoing major surgery have as much as a 46% chance of developing hypothermia in an operating facility where the ambient temperature is between 20 and 25 C [18,19]. The additional challenge specific to the practice of major burn surgery is the deficient epidermal barrier which compromises thermoregulation. During ‘prepping and draping’ for surgery, the patient has the dressings removed, and the burn wounds are washed with antiseptic solutions. Donor sites for autograft harvest, if required, are also prepared, and large cutaneous areas may be left exposed while the operating team scrub and gown. The induction of general anaesthesia itself impairs one’s autonomic means of regulating, distributing and conserving heat [32,43–45]. Patients are susceptible to three phases of hypothermia during anaesthesia, including a drop of 1–1.5 C during the first 60min, a slower linear decline in temperature from one to three hours after induction of general anaesthesia, and a subsequent plateau in core temperature at about 3–4h of anaesthesia. The nadir temperature, therefore, is likely a function of defective thermoregulation, a low ambient environmental temperature, heat redistribution from anaesthesia, the administration of relatively cool intravenous fluids and inhaled gases, and exposure of cutaneous surfaces and wounds [32,43–45]. Recent research from this unit demonstrated that those patients with major burn injury (greater than 20% TBSA) who
had surgical durations over four hours, as well as intraoperative hypothermia, had significantly increased rates of postoperative infectious and non-infectious complications when compared to a low risk cohort [32]. More than a quarter of all operative interventions for major burn injury had temperatures recorded below 36 C, many of these even prior to the initiation of surgery itself. While burn surgeons are generally well informed of the manifestations of hypothermia, strategies to ameliorate its impact have been applied in an ad hoc fashion. The practice of limiting excisions to specific maximum body surface areas [13], or operative times, for example, are generally adhered to principally because of anecdotal experience and convenience, instead of a scientific evidence-base or according to a standardized protocol [32]. The purpose of this quality improvement project was to reduce the incidence of perioperative hypothermia (Temperature <36 C) to below 10% of cases (i.e. by at least a half) in patients with major burn injury (Total Body Surface Area [TBSA] >15%), within a one year period.
2.
Methods
This quality improvement initiative was undertaken at the regional American Burn Association verified burn centre in Ontario, Canada. The unit serves a population of over 10 million people, admitting 350 patients a year, with approximately 30% resident in the Greater Toronto Area, and 70% from other areas of Ontario and beyond. Frequent reference is made to a retrospective chart review, undertaken in this unit and published in this journal, of 1111 patients who underwent 2171 surgeries for acute burn injury over a 10-year period. In addition to the statistically significant association noted between hypothermia and complications, it was discovered that as many as 29% of operative cases for major burn injury (TBSA >20%) had temperatures recorded below 36 C, and many of these occurred even before the onset of surgery itself [32]. Root cause analysis based on the above data, with a group of stakeholders, including representation from the surgical, anaesthetic, burn unit nursing and operating room nursing staff teams, identified prominent reasons for perioperative hypothermia. These included the impact of anaesthetic induction, prolonged ‘prepping and draping’, failure to adjust the ambient operating room temperature timeously, and preexisting hypothermia in the unit. A fishbone diagram of these reasons is demonstrated graphically (Fig. 1). Potential interventions were then considered which might most effectively target the prominent causes. We hypothesized that a few simple change concepts, iteratively introduced and tested via PDSA cycles, in addition to the dissemination of awareness of the impact of perioperative hypothermia on outcomes, might eliminate the nadir temperature commonly recorded intra-
Please cite this article in press as: A.D. Rogers, et al., A quality improvement project incorporating preoperative warming to prevent perioperative hypothermia in major burns, Burns (2018), https://doi.org/10.1016/j.burns.2018.02.012
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Fig. 1 – Ishikawa chart/fishbone diagram outlining factors contributing to perioperative hypothermia.
operatively. We also sought to test the hypothesis that the final recorded temperature was seldom the lowest. A variety of interventions on the ‘hierarchy of effectiveness’ were discussed, and initially focused almost exclusively on intraoperative measures. Preoperative warming was identified as the primary change initiative, with a forced air warming blanket, the ‘Bair Hugger’TM (3M), applied for at least one hour prior to transfer to the operating room for surgery. Eligible patients were those with major burns (TBSA >15%) whose recorded preoperative core temperatures were less than or equal to 37.5 C. Patients not eligible based on their preoperative temperature (for that case) were still followed throughout their hospital course, and may have had the intervention applied at a subsequent or previous case. The reasons for eligible patients not receiving the intervention were also documented, and these were used to inform decisions about improvements to this and subsequent interventions, including educational initiatives. In accordance with ‘model for improvement’ methodology, a family of measures, including outcome, process and balancing, were observed and recorded throughout the intervention process. The primary outcome measure was the lowest intraoperative temperature per case, with comparisons in incidence of hypothermia between pre- and post-intervention phases. Process measures included the adherence to the application of pre-warming (proportion of eligible patients who had prewarming applied), whether discussion about temperature management had occurred at the World Health Organisation surgical checklist [46], and whether the operating room temperature had been adjusted to its maximum (32 C) preoperatively (so that it was at or near the prescribed temperature at the initiation of surgery) by the first assistant
(fellow or resident). These were all measured as a percentage of eligible cases. Integral to this entire process was the accurate monitoring of pre-, intra-and postoperative core temperatures, and this was therefore a further process measure. Balancing measures included any delays resulting from the intervention, case cancellations, complaints of extra workload (e.g. by nursing stuff applying the preoperative warming device at the time of handover), additional unanticipated costs, ill effects or frustrations that might arise from any of the interventions. A time series design study was undertaken for the one year period between 1 November 2016 to 31 October 2017. Data collection included admission and discharge dates, demographics (age and sex), extent and aetiology of burn injury, number of major surgeries, prominent infective and noninfective complications, and a series of recorded temperatures during the perioperative period. Core temperatures, either nasopharyngeal or oesophageal, were used throughout. Data were collected prospectively on a proforma and corroborated with anaesthetic, dictated operative notes and nursing staff documentation from the electronic medical record, and transferred to Microsoft ExcelR for Mac (Version 15.33), with QI Macros 2017 (KnowWare International Inc.), which was then used for generating statistical process control charts and run charts for analysis, powered to detect statistical significance in quality improvement interventions. Further statistical analysis was undertaken if indicated using Socstatistics.com (2017 J. Stangroom). The ARECCI (A pRoject Ethics Community Consensus Initiative) Ethics Screening tool [47] was utilized; the study proposal received a minimal level of risk score (2), well below the threshold to require the institutional research ethics
Please cite this article in press as: A.D. Rogers, et al., A quality improvement project incorporating preoperative warming to prevent perioperative hypothermia in major burns, Burns (2018), https://doi.org/10.1016/j.burns.2018.02.012
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review process. ‘Bair Huggers’TM are routinely applied therapeutically in the context of overt hypothermia, often postoperatively, but historically, the only indication for prophylactic use in the burn centre has been intraoperatively. Preoperative warming is widely used in other surgical settings, however, supported by a growing body of literature demonstrating efficacy [35,48–53]. It is hypothesized that if hypothermia can be prevented in patients with major burns, so can its sequelae, a relationship outlined in previous research from this burn centre [32]. The interventions were not thought to pose any risk to patients. The source of the warmed air is a mobile unit, which is easily and effectively cleaned between uses. Nurses are familiar with the ‘Bair Hugger’TM, the modality in use in this unit, and it takes only a few minutes to apply correctly. Additional documentation required would be minimal. There was no external source of funding, nor any perceived or real conflict of interest identified.
3.
Results
Fifty-three patients (9 females and 42 males) were admitted with burn injuries over 15% TBSA in the one year period from 1 November 2016 to 31 October 2017. Their mean age was 50.3 years, and their mean body surface area involved was 34.83% (range 15–99%). Thirteen of these patients were excluded from investigation: comfort care measures were applied for twelve patients owing to the extent of injuries, their modified Baux Score, and the wishes of their next-of-kin. One other patient was excluded from consideration owing to the patient’s demise prior to surgery. Only one surgical patient died during her hospital stay. Forty patients (7 females and 33 males) were therefore considered for inclusion in this quality improvement initiative. Their mean age was 48.23 years, with a mean TBSA of 27.65% (range 15–66%). Eight of these patients had bronchoscopic evidence of inhalation injury and all but one sustained flame burn injuries. The mean hospital stay was 31.2days (range 9–114 days). 127 operations were undertaken over the period with a mean of 3.18 per patient (range 1–13). Patient demographic, clinical and treatment details are demonstrated in Table 1. Over the course of the intervention period, special cause variation was observed in the incidence of the primary outcome measure, inadvertent intraoperative hypothermia, with the proportion of cases was reduced to 13.7% (n=14/102) (Fig. 2). The percentage of hypothermic cases evaluated prior to the preoperative warming intervention was 24% (n=6/25), which was in keeping with historical control data [32]. The similar proportion of hypothermic cases observed during the baseline period and the historical control suggested that there was a stable baseline status quo to which a novel strategy could be introduced and tested reliably. It was noted that in only 32% (n=35) of cases was the final recorded intraoperative temperature in fact the lowest temperature. The distribution of lowest intraoperative temperature was evenly distributed between the three time periods, namely 0–1h, 1–3h, and more than 3h after the beginning of surgery. The proportion of eligible cases where the intervention was applied correctly increased from 28.6% during February 2017 to
85.7% during July, with a mean of 69% during the intervention period. Patients with core temperatures greater than 37.5 C were not eligible for the pre-warming intervention for the operation where they were hyperthermic, but were still followed throughout their perioperative course (and all subsequent ones), as they still were still susceptible to hypothermia, and other interventions, if applied correctly or timeously, may have influenced its development. The operating room temperature was correctly adjusted to 32 C, and an intraoperative ‘Bair Hugger’TM was placed correctly in over 70% of cases from March 2017. Temperature was specifically discussed in the WHO checklist in over 60% of cases evaluated. During the course of the intervention, in-service training sessions were iteratively introduced to reinforce the fact that normothermic patients (those with a temperature between 36.5 C and 37.5 C) are amongst the patients most likely to benefit from this one hour preoperative warming intervention. Cleaning staff were also engaged to desist from reducing the ambient operating room temperature and leaving the operating room door ajar during cleaning between cases, a practice intended to improve their comfort and efficiency. Staff survey evaluations revealed minimal additional burden of work to apply the pre-warming device. For the first surgical case of the day, which usually required patient transfer to the operating room between 7.45 and 8 am, night-shift nurses preferred to apply the ‘Bair Hugger’TM well before 7 am, to avoid placement interfering with final charting and hand-off to day-shift nurses between 7 and 7.30 am.
4.
Discussion
The proposed pathophysiology by which hypothermia inflicts its deleterious effects are widely published in the surgical and anaesthetic literature [19–32]. Hypothermia has a potent capacity to increase bleeding, by impairing platelet function by reducing thromboxane B2 levels, by compromising temperature dependent enzyme and cytokine function in the coagulation cascade, and by enhancing fibrinolysis, thereby destabilizing clot [20–24]. Even mild hypothermia predisposed patients undergoing total hip arthroplasty to greater blood loss and increased requirement for autologous blood transfusions [21]. Hypothermic patients undergoing elective abdominal aortic aneurysm repairs have been found to have greater fluid requirements, more blood transfusions, a greater need for inotropic agents and vasopressors, more frequent organ dysfunction, higher mortality rates and significantly prolonged hospital stays [25]. Cold also results in a shift in the oxyhaemoglobin dissociation curve, and increases in plasma catecholamine levels (with reductions in diastolic filling times), which together compromise tissue oxygen supply. The likelihood of wound and systemic complications is further exacerbated because humoral immunity is compromised by direct neutrophil dysfunction, vasoconstriction and hypoxia [21,23,26]. As a result, the risk of life-threatening infections, delayed healing and dehiscence is increased significantly [26–29], with as much as a threefold increase in surgical site infections described in hypothermic patients undergoing elective colorectal surgery [29]. In addition to the adverse effects already mentioned, hypothermia prolongs drug and toxin metabolism and
Please cite this article in press as: A.D. Rogers, et al., A quality improvement project incorporating preoperative warming to prevent perioperative hypothermia in major burns, Burns (2018), https://doi.org/10.1016/j.burns.2018.02.012
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Table 1 – Demographic and clinical details of patients who underwent surgery for burn injuries over 15% TBSA. Patient no. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Mean Range
Age TBSA Baux Number of Length (years) (%) Score procedures of stay (LOS) 53 46 38 56 57 27 31 29 38 29 61 36 42 61 62 76 45 44 26 63 48 43 53 58 76 27 53 49 25 24 50 54 56 62 71 70 47 70 24 49 48.23 24–76
18 50 45 25 20 15 20 43 18 25 20 24 15 65 16 18 17 25 66 50 65 56 26 15 15 24 19 18 38 23 29 17 19 15 22 22 30 17 25 16 27.65 15–66
71 96 83 81 77 42 51 72 56 54 81 60 57 126 78 94 62 69 92 113 113 99 79 73 91 51 72 67 63 47 79 71 75 77 93 92 77 87 49 65 75.88 42–113
1 5 7 7 1 1 2 4 3 2 7 2 3 10 2 1 2 1 13 7 3 6 2 1 2 1 1 2 5 2 1 1 3 1 3 2 5 1 3 1 3.18 1–13
16 41 41 53 13 11 17 34 18 17 65 19 27 102 18 28 21 18 114 87 15 60 16 24 24 14 14 18 51 20 13 20 52 9 54 34 21 16 34 17 31.2 9–114
LOS/ TBSA
Perioperative hypothermia (T<36) yes/no
0.89 0.82 0.91 2.12 0.65 0.73 0.85 0.79 1 0.68 3.25 0.79 1.8 1.57 1.13 1.56 1.26 0.72 1.73 1.74 N/A (died) 1.11 0.62 1.6 1.6 0.58 0.74 1 1.34 0.87 0.48 1.18 2.74 0.6 2.45 1.54 0.7 0.94 1.36 1.06 1.19
Y N Y Y N N Y N N Y N N Y Y Y N Y Y Y Y Y N Y Y N N Y N Y N Y N N N N Y N Y N N
Complications
C.Diff colitis/sepsis/pneumonia VAP/surgical site infection/skin graft loss AKI/mild stroke
ARDS/VAP Postoperative bleed Skin graft loss Surgical site infection Sepsis/VAP Upper GI bleed
Elbow joint and ulnar nerve exposure/VAP/sepsis VAP/CAUTI/sepsis/sacral pressure injury VAP/sepsis/died VAP/sepsis/lower GI bleed Surgical site infection
Cardiac arrest/VAP/surgical site infection Surgical site infection Surgical site infection Skin graft loss/sacral pressure injury
VAP/sepsis/CAUTI
TBSA — Total Body Surface Area. LOS/TBSA — length of hospital stay per percentage burn. CAUTI — catheter associated urinary tract infection. VAP — ventilator associated pneumonia. ARDS — acute respiratory distress syndrome.
clearance, resulting in delayed recovery from anaesthesia and increased drug side-effects. In patients undergoing microsurgical head and neck reconstruction, increased rates of partial and complete flap loss, dehiscence and seroma were more prevalent in those who were hypothermic intraoperatively [30,31]. As far as we are aware, ‘pre-warming’, an inexpensive and easily applicable strategy, has not been broadly applied in the burn surgery context [12,32,50–52]. This quality improvement initiative has suggested that it might contribute to reducing the incidence of inadvertent intraoperative hypothermia in patients with major burn injuries. This may in turn contribute to reduced complications, inter alia morbid cardiovascular
events, pneumonia, wound infections, delays in definitive closure of the burn wound, and deaths. Preoperative warming is intuitively most effective when intraoperative strategies are also standardized to prevent hypothermia, and within a culture where all relevant health care workers are cognisant of hypothermia’s potential impact. There is an increasing body of literature demonstrating the efficacy of preoperative warming in several elective and emergency surgical settings. This includes a clinical practice guideline developed with representation from five surgical specialties, as well as a systematic review of 14 trials [53,54], which suggest that forced air warming systems ameliorate the
Please cite this article in press as: A.D. Rogers, et al., A quality improvement project incorporating preoperative warming to prevent perioperative hypothermia in major burns, Burns (2018), https://doi.org/10.1016/j.burns.2018.02.012
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Fig. 2 – A statistical process control chart of all operative cases during a one year period showing the lowest recorded intraoperative temperature. Iterative changes are identified on the chart. Special cause variation is highlighted in red. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
inevitable drop in core temperature with induction of general anaesthesia. Tjoakarfa advocated for at least 30min of prewarming, and showed that intraoperative normothermia could then be maintained using reflective blankets rather than forced air warming devices [54]. We elected to apply at least one hour of preoperative warming at 43 C, given the unique susceptibility of patients with burn injuries. It is unclear whether one hour is the optimal time to apply prewarming in the context of burn surgery, and prospective studies may help to elucidate this further. Although we had inclusion criteria, we did not specifically aim for patients to reach a specific core temperature. As there are no detrimental effects of preoperative warming identified in the literature, there is no reason to restrict its application to patients with only major burn injuries, and next steps would include applying it to those with less extensive burn injuries and complex wounds. As protocols and eligibility criteria are adapted, in keeping with QI initiatives, it remains critically important to continue to engage with interdisciplinary stakeholders. It is obligatory in many institutions internationally, for all involved in surgical operations to attend and contribute to the World Health Organisation Surgical checklist, so that surgeries are executed in the most expeditious manner possible, but few routinely discuss the very tangible risk of hypothermia, how to prevent it, and how to address it timeously [32,46]. At our centre, based on this work, we intend to specifically document discussion of the temperature after fixed durations intraoperatively, rather than just at the start and end as advocated by the checklist [46]. Many intraoperative strategies are utilized, in this centre and others, to prevent or manage perioperative hypothermia in burn surgery. These include the pre-emptive adjustment of operating room ambient temperature, the use of intraoperative warming blankets, conductive warming pads and fluid warmers, measures to dry or replace soiled moist drapes, the routine
coverage of prepared and draped operative sites not being operated at that time, and the reduction of operating time (via staged surgeries and two team approaches [12,32,43–45]. It is unclear whether the severity of hypothermia (e.g. 34 C, 35 C or 36 C) or the duration, or both, is more virulent a risk factor, and further investigation is also warranted in this area. Patient comorbidities are also fundamentally important; age, body mass index and cardiorespiratory risk factors are likely the most consequential [32]. Because the burn centre is a self-contained facility with a core group of about 30 nursing staff and four burn surgeons, it is an ideal environment to introduce a change idea, and for this reason, it is often selected as the pilot for several hospital-wide quality improvement initiatives. Patients with major burns are presented at weekly rounds, attended by all the staff surgeons and senior members of the inter-disciplinary team, where there are opportunities to discuss the treatment course of each patient. Preoperative warming was also the topic of discussion at the burn centre steering committee meetings, on ward rounds, during research meetings, as well as during the burn centre’s re-verification by the American Burn Association which prioritizes quality improvement processes. Unfortunately, as noted in the process measures, some eligible patients did not have the preoperative warming device applied timeously or at all during the initial intervention period. This suggests that while a clear benefit overall was demonstrable in terms of reducing the incidence of perioperative hypothermia, additional benefit could have been forthcoming. The intervention initially required formal written prescription by physicians for it to be carried out. Greater adherence to preoperative warming for all eligible patients will likely be sustained by the introduction of a preoperative warming order (medical directive) in the admission order sets. Limitations of this quality improvement intervention include the inability to draw direct conclusions regarding
Please cite this article in press as: A.D. Rogers, et al., A quality improvement project incorporating preoperative warming to prevent perioperative hypothermia in major burns, Burns (2018), https://doi.org/10.1016/j.burns.2018.02.012
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the impact of pre-warming on reducing morbidity and mortality (as might be observed via ‘traditional research’ methodologies like a prospective randomized trial); this QI initiative focuses specifically on creating a culture which prioritizes the prevention of inadvertent hypothermia. Burn associations are increasingly embracing QI as essential to stimulate meaningful and sustainable change in burn centres; QI is also increasingly incorporated as part of verification criteria. The Model for Improvement methodology, utilized here, is an approach to continuous quality improvement where changes are tested in small cycles that involve planning, doing, studying and acting. Each cycle starts with theories and facilitates their evolution into knowledge that can inform action, and, ultimately result in sustainable positive results.
5.
Conclusion
Hypothermia is associated with a host of life-threatening consequences in the context of major burn surgery. This quality improvement initiative motivates for the widespread application of preoperative warming, which, when part of a consistently applied intraoperative protocol, can contribute to the maintenance of normothermia during the perioperative period.
Conflict of interest The authors have no conflict of interest to declare.
Funding No funding or financial support was received to undertake this project.
Acknowledgements We acknowledge the burn surgeons, the anaesthetists, the operating room and burn centre nursing staff of the Ross Tilley Burn Centre for their support and contribution to the execution of this quality improvement initiative. REFERENCES
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[24] Cavallini M, Preis FWB, Casati A. Effects of mild hypothermia on blood coagulation in patients undergoing elective plastic surgery. Plast Recon Surg 2005;116(1)316––321 PMID: 15988284. [25] Bush HL, Hydo LJ, Fischer E, Fantani GA, Silane MF, Barie PS. Hypothermia during elective abdominal aortic aneurysm repair: the high price of avoidable morbidity. J Vasc Surg 1995;21:392–402 PMID: 7877221. [26] Sessler DI, Kurz A, Lenhardt R. Re: hypothermia reduces resistance to surgical wound infections. Am Surg 1999;65 (December (12))1193–6 PMID: 10597075. [27] Pessaux P, Msika S, Atalla D, Hay JM, Flamant Y. Risk factors for postoperative infectious complications in noncolorectal abdominal surgery. Arch Surg 2003;138:314–24 PMID: 12611581. [28] Leaper D, Ousey K. Evidence update on prevention of surgical site infection. Curr Opin Infect Dis 2015;28(April (2))158––163, doi:http://dx.doi.org/10.1097/QCO.0000000000000144 PMID: 25692267. [29] Kurz A, Sessler DI, Lenhardt R. Perioperative nomothermia to reduce the incidence of surgical-wound infection and shorten hospitalisation. Study of Wound Infection and Temperature Group. N Eng J Med 1996;334(19)1209–15 PMID: 8606715. [30] Dos Passos G, Rogers AD, Price CE, Pienaar C, van Zyl HE, Hudson DA. Loupe magnification for head and neck free flap reconstruction in a developing country. Eur J Plast Surg 2015;38:363–70. [31] Offodile AC, Aherrera A, Wenger J, Rajab TK, Guo L. Impact of increasing operative time on the incidence of early failure and complications following free tissue transfer? A risk factor analysis of 2,008 patients from the ACS-NSQIP database. Microsurgery 2015(March), doi:http://dx.doi.org/10.1002/ micr.22387 PMID: 25752264. [32] Ziolkowski N, Rogers AD, Xiong W, Hong B, Patel S, Trull B, et al. The impact of operative time and hypothermia in major burns. Burns 2017;(October (17))30540, doi:http://dx.doi.org/10.1016/ j.burn.2017.10.001 Pii: S0305-4179 PMID: 29089204. [33] Abelha FJ, Castro MA, Neves AM, Landeiro NM, Santos CC. Hypothermia in a surgical intensive care unit. BMC Anesthesiol 2005;5(7)1–10 PMID: 15938757. [34] Hynson JM, Sessler DI, Moayeri A, McGuire BS, Schroeder M. The effects of preinduction temperature and blood pressure during propofol/nitrous oxide anesthesia. Anesthesiology 1993;79:219–28 PMID: 83432834. [35] Kumar S, Wong PF, Melling AC, Leaper DJ. Effects of perioperative hypothermia and warming in surgical practice. Int Wound J 2005;2(September (3))193–204 PMID: 16618324. [36] Sagraves SG, Toschlog EA, Rotondo MF. Damage control surgery—the intensivist’s role. J Intensive Care Med 2006;21 (January–February (1))5–16 PMID: 16698739. [37] Shapiro MB, Jenkins DH, Schwab CW, Rotondo MF. Damage control: collective review. J Trauma 2000;49(November (5))969– 78 PMID: 11086798. [38] Johnson JW, Gracias VH, Schwab CW, Reilly PM, Kauder DR, Shapiro MB, et al. Evolution in damage control for exsanguinating penetrating abdominal injury. J Trauma 2001;51(August (2))261–9 discussion 269-71. PMID: 11493783. [39] Rotondo MF, Zonies DH. The damage control sequence and underlying logic. Surg Clin North Am 1997;77(August (4))761–– 777 PMID: 9291979.
[40] Rotondo MF, Schwab CW, McGonigal MD, Phillips 3rd GR, Fruchterman TM, Kauder DR, et al. ‘Damage control’: an approach for improved survival in exsanguinating penetrating abdominal injury. J Trauma 1993;35(September (3))375–82 discussion 382-3. PMID: 8371295. [41] Cosgriff N, Moore EE, Sauaia A, Kenny-Moynihan M, Burch JM, Galloway B. Predicting life-threatening coagulopathy in the massively transfused trauma patient: hypothermia and acidosis revisited. J Trauma 1997;42:857–61 PMID: 9191667. [42] Tsuei BJ, Kearney PA. Hypothermia in the trauma patient. Injury 2004;35:7––15 PMID: 14728949. [43] Sessler DI. Temperature monitoring and perioperative thermoregulation. Anaesthesiology 2008;109:318–38 PMID: 18648241. [44] Kurz A. Thermoregulation in anesthesia and intensive care medicine. Best Pract Res Clin Anaesthesiol 200822(December (4)) vii–viii. PMID: 19137806. [45] Taguchi A, Kurz A. Thermal management of the patient: where does the patient lose and/or gain temperature? Curr Opin Anaesthesiol 2005;18(December (6))632–9 PMID: 16534304-48. [46] Haynes AB, Weiser TG, Berry WR, Lipsitz SR, Breizat AH, Dellinger EP, et al. A surgical safety checklist to reduce morbidity and mortality in a global population. N Engl J Med 2009;360(January (5))491–9, doi:http://dx.doi.org/10.1056/ NEJMsa0810119 Epub 2009 Jan 14 PMID: 19144931. [47] The ARECCI Ethics Screening Tool. September 2013 Version. www.aihealthsolutions.ca/arecci/screening. [Accessed 5 November 2016]. [48] Casey JG, King RA, Armstrong P. Is there a thermal benefit from preoperative warming in children? Pediatric Anesth 2010;20:63–71. [49] Emmert A, Franke R, Brandes IF, Hinterthaner M, Danner BC, Bauer M, et al. Comparison of conductive and convective warming in patients undergoing video-assisted thoracic surgery: A prospective randomsied clinical trial. Thor Cardio Surg. doi:https://doi.org/10.1055/s-0036-1583766. ISSN 01716425. PMID: 27177263. [50] Wong PF, Kumar S, Bohra A, Whetter D, Leaper DJ. Randomized clinical trial of perioperative systemic warming in major elective abdominal surgery. Br J Surg 2007;94(April (4))421–6 PMID:17380549. [51] Saleh M, Barr TM. The impact of slow rewarming on inotropy, tissue metabolism, and “after drop” of body temperature in pediatric patients. J Extra Corpor Technol 2005;37(June (2))173– 9 PMID: 16117455. [52] Gorges M, West NC, Cheung W, Zhou G, Miyanji F, Whyte SD. Preoperative warming and undesired surgical and anaesthesia outcomes in pediatric spinal surgery — a retrospective cohort study. Pediatric Anes 2016;26:866–75 PMID: 27312044. [53] de Brito Poveda V, Clark A, Galvao C. A systematic review on the effectiveness of prewarming to prevent perioperative hypothermia. J Clin Nurs 2012;22:906–18 PMID: 22978458. [54] Tjoakarfa C, David V, Ko A, Hau R. Reflective blankets are as effective as forced air warmers in maintaining patient normothermia during hip and knee arthroplasty surgery. J Arthroplasty 2017;32(2)624–7, doi:http://dx.doi.org/10.1016/j. arth.2016.07.015 Epub 2016 Jul 21. PMID: 27546475.
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A quality improvement project incorporating preoperative warming to prevent perioperative hypothermia in major burns A.D. Rogers a,b, *, M. Saggaf a,b , N. Ziolkowski a,b a b
Ross Tilley Burn Centre, Sunnybrook Health Sciences Centre, Toronto, Canada Division of Plastic and Reconstructive Surgery, Department of Surgery, University of Toronto, Canada
article info
abstract
Article history:
Background: Patients with extensive burn injuries are susceptible to a host of
Accepted 12 February 2018
accompanying adverse effects should they develop perioperative hypothermia, which
Available online xxx
occurs in up to 1/4 of all major burn cases. This quality improvement project aimed to reduce the incidence of perioperative hypothermia to below 10% of cases in patients
Keywords: Quality improvement Perioperative hypothermia Surgical complications Burn surgery Preoperative warming
with major burn (Total Body Surface Area [TBSA] >15%), within a one year period. Methods: A baseline diagnostic phase was undertaken to provide a greater understanding of the incidence, natural history and risk factors of perioperative hypothermia. We also reviewed and reinforced intraoperative measures in current use, including preemptive adjustment of the ambient temperature, underbody warming mattress use, warming blanket application over areas not operated, regular temperature monitoring, and discussion at the WHO surgical checklist. Preoperative forced air warming with a ‘Bair Hugger’TM was identified as a sound change initiative, a strategy applied to good effect in other surgical settings. The primary outcome measure was the percentage of cases of perioperative hypothermia (<36 C), utilizing a time series design for the period between 1 November 2016 and 31 October 2017. Results: 53 patients with burn greater than 15% TBSA were admitted over the one year period. Of these, 40 patients required 127 operative procedures. Their mean age was 48.23 years, their mean TBSA was 27.65% (range 15–75%), and their mean length of hospital stay was 31.2 days. After the introduction of pre-warming, the proportion of cases of inadvertent hypothermia reduced to 13.77% (n=14/102), with special cause variation, from 24% (n=6/25) in the baseline data collection period. The final temperature correlated with the lowest temperature recorded in only 32% of cases. Based on stakeholder feedback and consensus from the literature, an algorithm was developed which forms the basis for a medical directive for preoperative warming for eligible patients. No significant balancing measures were identified, nor any undue costs incurred. Discussion: The inevitable drop in temperature is ameliorated by sound perioperative practices, rather than just intraoperative ones. This initiative demonstrated the potential benefits of, and motivates for, the broad application of preoperative warming in the context of major acute burn surgery. Further investigations include PDSA cycles to determine whether the duration or degree of intraoperative hypothermia is more virulent. To
* Corresponding author at: D714, Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Toronto, Ontario, M4N 3M5, Canada. E-mail address: [email protected] (A.D. Rogers). https://doi.org/10.1016/j.burns.2018.02.012 0305-4179/© 2018 Elsevier Ltd and ISBI. All rights reserved.
Please cite this article in press as: A.D. Rogers, et al., A quality improvement project incorporating preoperative warming to prevent perioperative hypothermia in major burns, Burns (2018), https://doi.org/10.1016/j.burns.2018.02.012
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consolidate the pre-warming initiative, we have introduced a standard order within our admission order sets to include preoperative warming for all eligible patients. © 2018 Elsevier Ltd and ISBI. All rights reserved.
1.
Background
Burn remains a prominent global health burden, with over 11 million burn injuries requiring medical attention annually, and is a leading cause of traumatic mortality and morbidity [1]. For full thickness and deep partial thickness burns, the widelyaccepted practice, after initial critical care assessment and fluid resuscitation, is early excision and autografting [2–11]. While outcomes are undoubtedly improved because of this approach, early aggressive debridement exposes susceptible patients to the sequelae of hypothermia in the perioperative period [12–14]. A recent review highlighted the scarcity of literature on the sequelae of perioperative hypothermia, and challenged the burn community to “re-evaluate current dogma” regarding surgical principles and practice [12]. Hypothermia, a core temperature under 36 C, is known to have a host of accompanying adverse effects, manifesting as morbid cardiovascular events, infections, a propensity for greater blood loss, prolonged drug metabolism, as well as delays in obtaining definitive wound healing. These, in turn, may necessitate greater periods of mechanical ventilation, antibiotics, inotropes, opiate analgesics, sedatives and blood products, as well as further operative interventions [15–35]. These ill effects have been described in a wide variety of elective and emergency surgical settings, and notably, in the field of trauma surgery [15,16], its inclusion in the ‘lethal triad’ added impetus to ‘damage control’ surgery [36–42]. Even without burn injury, patients undergoing major surgery have as much as a 46% chance of developing hypothermia in an operating facility where the ambient temperature is between 20 and 25 C [18,19]. The additional challenge specific to the practice of major burn surgery is the deficient epidermal barrier which compromises thermoregulation. During ‘prepping and draping’ for surgery, the patient has the dressings removed, and the burn wounds are washed with antiseptic solutions. Donor sites for autograft harvest, if required, are also prepared, and large cutaneous areas may be left exposed while the operating team scrub and gown. The induction of general anaesthesia itself impairs one’s autonomic means of regulating, distributing and conserving heat [32,43–45]. Patients are susceptible to three phases of hypothermia during anaesthesia, including a drop of 1–1.5 C during the first 60min, a slower linear decline in temperature from one to three hours after induction of general anaesthesia, and a subsequent plateau in core temperature at about 3–4h of anaesthesia. The nadir temperature, therefore, is likely a function of defective thermoregulation, a low ambient environmental temperature, heat redistribution from anaesthesia, the administration of relatively cool intravenous fluids and inhaled gases, and exposure of cutaneous surfaces and wounds [32,43–45]. Recent research from this unit demonstrated that those patients with major burn injury (greater than 20% TBSA) who
had surgical durations over four hours, as well as intraoperative hypothermia, had significantly increased rates of postoperative infectious and non-infectious complications when compared to a low risk cohort [32]. More than a quarter of all operative interventions for major burn injury had temperatures recorded below 36 C, many of these even prior to the initiation of surgery itself. While burn surgeons are generally well informed of the manifestations of hypothermia, strategies to ameliorate its impact have been applied in an ad hoc fashion. The practice of limiting excisions to specific maximum body surface areas [13], or operative times, for example, are generally adhered to principally because of anecdotal experience and convenience, instead of a scientific evidence-base or according to a standardized protocol [32]. The purpose of this quality improvement project was to reduce the incidence of perioperative hypothermia (Temperature <36 C) to below 10% of cases (i.e. by at least a half) in patients with major burn injury (Total Body Surface Area [TBSA] >15%), within a one year period.
2.
Methods
This quality improvement initiative was undertaken at the regional American Burn Association verified burn centre in Ontario, Canada. The unit serves a population of over 10 million people, admitting 350 patients a year, with approximately 30% resident in the Greater Toronto Area, and 70% from other areas of Ontario and beyond. Frequent reference is made to a retrospective chart review, undertaken in this unit and published in this journal, of 1111 patients who underwent 2171 surgeries for acute burn injury over a 10-year period. In addition to the statistically significant association noted between hypothermia and complications, it was discovered that as many as 29% of operative cases for major burn injury (TBSA >20%) had temperatures recorded below 36 C, and many of these occurred even before the onset of surgery itself [32]. Root cause analysis based on the above data, with a group of stakeholders, including representation from the surgical, anaesthetic, burn unit nursing and operating room nursing staff teams, identified prominent reasons for perioperative hypothermia. These included the impact of anaesthetic induction, prolonged ‘prepping and draping’, failure to adjust the ambient operating room temperature timeously, and preexisting hypothermia in the unit. A fishbone diagram of these reasons is demonstrated graphically (Fig. 1). Potential interventions were then considered which might most effectively target the prominent causes. We hypothesized that a few simple change concepts, iteratively introduced and tested via PDSA cycles, in addition to the dissemination of awareness of the impact of perioperative hypothermia on outcomes, might eliminate the nadir temperature commonly recorded intra-
Please cite this article in press as: A.D. Rogers, et al., A quality improvement project incorporating preoperative warming to prevent perioperative hypothermia in major burns, Burns (2018), https://doi.org/10.1016/j.burns.2018.02.012
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Fig. 1 – Ishikawa chart/fishbone diagram outlining factors contributing to perioperative hypothermia.
operatively. We also sought to test the hypothesis that the final recorded temperature was seldom the lowest. A variety of interventions on the ‘hierarchy of effectiveness’ were discussed, and initially focused almost exclusively on intraoperative measures. Preoperative warming was identified as the primary change initiative, with a forced air warming blanket, the ‘Bair Hugger’TM (3M), applied for at least one hour prior to transfer to the operating room for surgery. Eligible patients were those with major burns (TBSA >15%) whose recorded preoperative core temperatures were less than or equal to 37.5 C. Patients not eligible based on their preoperative temperature (for that case) were still followed throughout their hospital course, and may have had the intervention applied at a subsequent or previous case. The reasons for eligible patients not receiving the intervention were also documented, and these were used to inform decisions about improvements to this and subsequent interventions, including educational initiatives. In accordance with ‘model for improvement’ methodology, a family of measures, including outcome, process and balancing, were observed and recorded throughout the intervention process. The primary outcome measure was the lowest intraoperative temperature per case, with comparisons in incidence of hypothermia between pre- and post-intervention phases. Process measures included the adherence to the application of pre-warming (proportion of eligible patients who had prewarming applied), whether discussion about temperature management had occurred at the World Health Organisation surgical checklist [46], and whether the operating room temperature had been adjusted to its maximum (32 C) preoperatively (so that it was at or near the prescribed temperature at the initiation of surgery) by the first assistant
(fellow or resident). These were all measured as a percentage of eligible cases. Integral to this entire process was the accurate monitoring of pre-, intra-and postoperative core temperatures, and this was therefore a further process measure. Balancing measures included any delays resulting from the intervention, case cancellations, complaints of extra workload (e.g. by nursing stuff applying the preoperative warming device at the time of handover), additional unanticipated costs, ill effects or frustrations that might arise from any of the interventions. A time series design study was undertaken for the one year period between 1 November 2016 to 31 October 2017. Data collection included admission and discharge dates, demographics (age and sex), extent and aetiology of burn injury, number of major surgeries, prominent infective and noninfective complications, and a series of recorded temperatures during the perioperative period. Core temperatures, either nasopharyngeal or oesophageal, were used throughout. Data were collected prospectively on a proforma and corroborated with anaesthetic, dictated operative notes and nursing staff documentation from the electronic medical record, and transferred to Microsoft ExcelR for Mac (Version 15.33), with QI Macros 2017 (KnowWare International Inc.), which was then used for generating statistical process control charts and run charts for analysis, powered to detect statistical significance in quality improvement interventions. Further statistical analysis was undertaken if indicated using Socstatistics.com (2017 J. Stangroom). The ARECCI (A pRoject Ethics Community Consensus Initiative) Ethics Screening tool [47] was utilized; the study proposal received a minimal level of risk score (2), well below the threshold to require the institutional research ethics
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review process. ‘Bair Huggers’TM are routinely applied therapeutically in the context of overt hypothermia, often postoperatively, but historically, the only indication for prophylactic use in the burn centre has been intraoperatively. Preoperative warming is widely used in other surgical settings, however, supported by a growing body of literature demonstrating efficacy [35,48–53]. It is hypothesized that if hypothermia can be prevented in patients with major burns, so can its sequelae, a relationship outlined in previous research from this burn centre [32]. The interventions were not thought to pose any risk to patients. The source of the warmed air is a mobile unit, which is easily and effectively cleaned between uses. Nurses are familiar with the ‘Bair Hugger’TM, the modality in use in this unit, and it takes only a few minutes to apply correctly. Additional documentation required would be minimal. There was no external source of funding, nor any perceived or real conflict of interest identified.
3.
Results
Fifty-three patients (9 females and 42 males) were admitted with burn injuries over 15% TBSA in the one year period from 1 November 2016 to 31 October 2017. Their mean age was 50.3 years, and their mean body surface area involved was 34.83% (range 15–99%). Thirteen of these patients were excluded from investigation: comfort care measures were applied for twelve patients owing to the extent of injuries, their modified Baux Score, and the wishes of their next-of-kin. One other patient was excluded from consideration owing to the patient’s demise prior to surgery. Only one surgical patient died during her hospital stay. Forty patients (7 females and 33 males) were therefore considered for inclusion in this quality improvement initiative. Their mean age was 48.23 years, with a mean TBSA of 27.65% (range 15–66%). Eight of these patients had bronchoscopic evidence of inhalation injury and all but one sustained flame burn injuries. The mean hospital stay was 31.2days (range 9–114 days). 127 operations were undertaken over the period with a mean of 3.18 per patient (range 1–13). Patient demographic, clinical and treatment details are demonstrated in Table 1. Over the course of the intervention period, special cause variation was observed in the incidence of the primary outcome measure, inadvertent intraoperative hypothermia, with the proportion of cases was reduced to 13.7% (n=14/102) (Fig. 2). The percentage of hypothermic cases evaluated prior to the preoperative warming intervention was 24% (n=6/25), which was in keeping with historical control data [32]. The similar proportion of hypothermic cases observed during the baseline period and the historical control suggested that there was a stable baseline status quo to which a novel strategy could be introduced and tested reliably. It was noted that in only 32% (n=35) of cases was the final recorded intraoperative temperature in fact the lowest temperature. The distribution of lowest intraoperative temperature was evenly distributed between the three time periods, namely 0–1h, 1–3h, and more than 3h after the beginning of surgery. The proportion of eligible cases where the intervention was applied correctly increased from 28.6% during February 2017 to
85.7% during July, with a mean of 69% during the intervention period. Patients with core temperatures greater than 37.5 C were not eligible for the pre-warming intervention for the operation where they were hyperthermic, but were still followed throughout their perioperative course (and all subsequent ones), as they still were still susceptible to hypothermia, and other interventions, if applied correctly or timeously, may have influenced its development. The operating room temperature was correctly adjusted to 32 C, and an intraoperative ‘Bair Hugger’TM was placed correctly in over 70% of cases from March 2017. Temperature was specifically discussed in the WHO checklist in over 60% of cases evaluated. During the course of the intervention, in-service training sessions were iteratively introduced to reinforce the fact that normothermic patients (those with a temperature between 36.5 C and 37.5 C) are amongst the patients most likely to benefit from this one hour preoperative warming intervention. Cleaning staff were also engaged to desist from reducing the ambient operating room temperature and leaving the operating room door ajar during cleaning between cases, a practice intended to improve their comfort and efficiency. Staff survey evaluations revealed minimal additional burden of work to apply the pre-warming device. For the first surgical case of the day, which usually required patient transfer to the operating room between 7.45 and 8 am, night-shift nurses preferred to apply the ‘Bair Hugger’TM well before 7 am, to avoid placement interfering with final charting and hand-off to day-shift nurses between 7 and 7.30 am.
4.
Discussion
The proposed pathophysiology by which hypothermia inflicts its deleterious effects are widely published in the surgical and anaesthetic literature [19–32]. Hypothermia has a potent capacity to increase bleeding, by impairing platelet function by reducing thromboxane B2 levels, by compromising temperature dependent enzyme and cytokine function in the coagulation cascade, and by enhancing fibrinolysis, thereby destabilizing clot [20–24]. Even mild hypothermia predisposed patients undergoing total hip arthroplasty to greater blood loss and increased requirement for autologous blood transfusions [21]. Hypothermic patients undergoing elective abdominal aortic aneurysm repairs have been found to have greater fluid requirements, more blood transfusions, a greater need for inotropic agents and vasopressors, more frequent organ dysfunction, higher mortality rates and significantly prolonged hospital stays [25]. Cold also results in a shift in the oxyhaemoglobin dissociation curve, and increases in plasma catecholamine levels (with reductions in diastolic filling times), which together compromise tissue oxygen supply. The likelihood of wound and systemic complications is further exacerbated because humoral immunity is compromised by direct neutrophil dysfunction, vasoconstriction and hypoxia [21,23,26]. As a result, the risk of life-threatening infections, delayed healing and dehiscence is increased significantly [26–29], with as much as a threefold increase in surgical site infections described in hypothermic patients undergoing elective colorectal surgery [29]. In addition to the adverse effects already mentioned, hypothermia prolongs drug and toxin metabolism and
Please cite this article in press as: A.D. Rogers, et al., A quality improvement project incorporating preoperative warming to prevent perioperative hypothermia in major burns, Burns (2018), https://doi.org/10.1016/j.burns.2018.02.012
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Table 1 – Demographic and clinical details of patients who underwent surgery for burn injuries over 15% TBSA. Patient no. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Mean Range
Age TBSA Baux Number of Length (years) (%) Score procedures of stay (LOS) 53 46 38 56 57 27 31 29 38 29 61 36 42 61 62 76 45 44 26 63 48 43 53 58 76 27 53 49 25 24 50 54 56 62 71 70 47 70 24 49 48.23 24–76
18 50 45 25 20 15 20 43 18 25 20 24 15 65 16 18 17 25 66 50 65 56 26 15 15 24 19 18 38 23 29 17 19 15 22 22 30 17 25 16 27.65 15–66
71 96 83 81 77 42 51 72 56 54 81 60 57 126 78 94 62 69 92 113 113 99 79 73 91 51 72 67 63 47 79 71 75 77 93 92 77 87 49 65 75.88 42–113
1 5 7 7 1 1 2 4 3 2 7 2 3 10 2 1 2 1 13 7 3 6 2 1 2 1 1 2 5 2 1 1 3 1 3 2 5 1 3 1 3.18 1–13
16 41 41 53 13 11 17 34 18 17 65 19 27 102 18 28 21 18 114 87 15 60 16 24 24 14 14 18 51 20 13 20 52 9 54 34 21 16 34 17 31.2 9–114
LOS/ TBSA
Perioperative hypothermia (T<36) yes/no
0.89 0.82 0.91 2.12 0.65 0.73 0.85 0.79 1 0.68 3.25 0.79 1.8 1.57 1.13 1.56 1.26 0.72 1.73 1.74 N/A (died) 1.11 0.62 1.6 1.6 0.58 0.74 1 1.34 0.87 0.48 1.18 2.74 0.6 2.45 1.54 0.7 0.94 1.36 1.06 1.19
Y N Y Y N N Y N N Y N N Y Y Y N Y Y Y Y Y N Y Y N N Y N Y N Y N N N N Y N Y N N
Complications
C.Diff colitis/sepsis/pneumonia VAP/surgical site infection/skin graft loss AKI/mild stroke
ARDS/VAP Postoperative bleed Skin graft loss Surgical site infection Sepsis/VAP Upper GI bleed
Elbow joint and ulnar nerve exposure/VAP/sepsis VAP/CAUTI/sepsis/sacral pressure injury VAP/sepsis/died VAP/sepsis/lower GI bleed Surgical site infection
Cardiac arrest/VAP/surgical site infection Surgical site infection Surgical site infection Skin graft loss/sacral pressure injury
VAP/sepsis/CAUTI
TBSA — Total Body Surface Area. LOS/TBSA — length of hospital stay per percentage burn. CAUTI — catheter associated urinary tract infection. VAP — ventilator associated pneumonia. ARDS — acute respiratory distress syndrome.
clearance, resulting in delayed recovery from anaesthesia and increased drug side-effects. In patients undergoing microsurgical head and neck reconstruction, increased rates of partial and complete flap loss, dehiscence and seroma were more prevalent in those who were hypothermic intraoperatively [30,31]. As far as we are aware, ‘pre-warming’, an inexpensive and easily applicable strategy, has not been broadly applied in the burn surgery context [12,32,50–52]. This quality improvement initiative has suggested that it might contribute to reducing the incidence of inadvertent intraoperative hypothermia in patients with major burn injuries. This may in turn contribute to reduced complications, inter alia morbid cardiovascular
events, pneumonia, wound infections, delays in definitive closure of the burn wound, and deaths. Preoperative warming is intuitively most effective when intraoperative strategies are also standardized to prevent hypothermia, and within a culture where all relevant health care workers are cognisant of hypothermia’s potential impact. There is an increasing body of literature demonstrating the efficacy of preoperative warming in several elective and emergency surgical settings. This includes a clinical practice guideline developed with representation from five surgical specialties, as well as a systematic review of 14 trials [53,54], which suggest that forced air warming systems ameliorate the
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Fig. 2 – A statistical process control chart of all operative cases during a one year period showing the lowest recorded intraoperative temperature. Iterative changes are identified on the chart. Special cause variation is highlighted in red. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
inevitable drop in core temperature with induction of general anaesthesia. Tjoakarfa advocated for at least 30min of prewarming, and showed that intraoperative normothermia could then be maintained using reflective blankets rather than forced air warming devices [54]. We elected to apply at least one hour of preoperative warming at 43 C, given the unique susceptibility of patients with burn injuries. It is unclear whether one hour is the optimal time to apply prewarming in the context of burn surgery, and prospective studies may help to elucidate this further. Although we had inclusion criteria, we did not specifically aim for patients to reach a specific core temperature. As there are no detrimental effects of preoperative warming identified in the literature, there is no reason to restrict its application to patients with only major burn injuries, and next steps would include applying it to those with less extensive burn injuries and complex wounds. As protocols and eligibility criteria are adapted, in keeping with QI initiatives, it remains critically important to continue to engage with interdisciplinary stakeholders. It is obligatory in many institutions internationally, for all involved in surgical operations to attend and contribute to the World Health Organisation Surgical checklist, so that surgeries are executed in the most expeditious manner possible, but few routinely discuss the very tangible risk of hypothermia, how to prevent it, and how to address it timeously [32,46]. At our centre, based on this work, we intend to specifically document discussion of the temperature after fixed durations intraoperatively, rather than just at the start and end as advocated by the checklist [46]. Many intraoperative strategies are utilized, in this centre and others, to prevent or manage perioperative hypothermia in burn surgery. These include the pre-emptive adjustment of operating room ambient temperature, the use of intraoperative warming blankets, conductive warming pads and fluid warmers, measures to dry or replace soiled moist drapes, the routine
coverage of prepared and draped operative sites not being operated at that time, and the reduction of operating time (via staged surgeries and two team approaches [12,32,43–45]. It is unclear whether the severity of hypothermia (e.g. 34 C, 35 C or 36 C) or the duration, or both, is more virulent a risk factor, and further investigation is also warranted in this area. Patient comorbidities are also fundamentally important; age, body mass index and cardiorespiratory risk factors are likely the most consequential [32]. Because the burn centre is a self-contained facility with a core group of about 30 nursing staff and four burn surgeons, it is an ideal environment to introduce a change idea, and for this reason, it is often selected as the pilot for several hospital-wide quality improvement initiatives. Patients with major burns are presented at weekly rounds, attended by all the staff surgeons and senior members of the inter-disciplinary team, where there are opportunities to discuss the treatment course of each patient. Preoperative warming was also the topic of discussion at the burn centre steering committee meetings, on ward rounds, during research meetings, as well as during the burn centre’s re-verification by the American Burn Association which prioritizes quality improvement processes. Unfortunately, as noted in the process measures, some eligible patients did not have the preoperative warming device applied timeously or at all during the initial intervention period. This suggests that while a clear benefit overall was demonstrable in terms of reducing the incidence of perioperative hypothermia, additional benefit could have been forthcoming. The intervention initially required formal written prescription by physicians for it to be carried out. Greater adherence to preoperative warming for all eligible patients will likely be sustained by the introduction of a preoperative warming order (medical directive) in the admission order sets. Limitations of this quality improvement intervention include the inability to draw direct conclusions regarding
Please cite this article in press as: A.D. Rogers, et al., A quality improvement project incorporating preoperative warming to prevent perioperative hypothermia in major burns, Burns (2018), https://doi.org/10.1016/j.burns.2018.02.012
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the impact of pre-warming on reducing morbidity and mortality (as might be observed via ‘traditional research’ methodologies like a prospective randomized trial); this QI initiative focuses specifically on creating a culture which prioritizes the prevention of inadvertent hypothermia. Burn associations are increasingly embracing QI as essential to stimulate meaningful and sustainable change in burn centres; QI is also increasingly incorporated as part of verification criteria. The Model for Improvement methodology, utilized here, is an approach to continuous quality improvement where changes are tested in small cycles that involve planning, doing, studying and acting. Each cycle starts with theories and facilitates their evolution into knowledge that can inform action, and, ultimately result in sustainable positive results.
5.
Conclusion
Hypothermia is associated with a host of life-threatening consequences in the context of major burn surgery. This quality improvement initiative motivates for the widespread application of preoperative warming, which, when part of a consistently applied intraoperative protocol, can contribute to the maintenance of normothermia during the perioperative period.
Conflict of interest The authors have no conflict of interest to declare.
Funding No funding or financial support was received to undertake this project.
Acknowledgements We acknowledge the burn surgeons, the anaesthetists, the operating room and burn centre nursing staff of the Ross Tilley Burn Centre for their support and contribution to the execution of this quality improvement initiative. REFERENCES
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Please cite this article in press as: A.D. Rogers, et al., A quality improvement project incorporating preoperative warming to prevent perioperative hypothermia in major burns, Burns (2018), https://doi.org/10.1016/j.burns.2018.02.012