Forced-air warming and ultra-clean ventilation do not mix

Temperature Outcomes without heater cooler units in adult patients supported with extracorporeal membrane oxygenation: A retrospective cohort study

INTRODUCTION

Heater-cooler units (HCUs) are frequently incorporated into extracorporeal membrane oxygenation (ECMO) circuits to help maintain patient normothermia. However, these devices may be associated with increased cost and infection risk. This study describes our institution's experience managing adult ECMO patients without the routine use of in-circuit HCUs.

METHODS

We performed a retrospective analysis of adult patients treated with veno-venous (VV) or veno-arterial (VA) ECMO at our institution. The primary outcomes were rates of HCU use and the relative duration of the ECMO treatment course in which patients maintained normothermia (36-37.5°C), with and without HCUs. Secondary outcomes of mortality and ECMO-related complications were planned across HCU and non-HCU groups; exploratory analyses were performed across a 75% "ECMO time in normothermia" threshold.

RESULTS

Among a cohort of 71 patients, zero (0%) were managed with in-circuit HCUs. A majority of ECMO patient-hours were spent in the normothermic range. Median and mean percentages of ECMO normothermia time were 75% (IQR 49%-81%) and 62% (SD ± 27%). Twenty-nine patients (40%) met the threshold of 75% ECMO normothermia time, as used to evaluate secondary outcomes. At this threshold, mortality risk was significantly higher among the non-normothermic cohort; other ECMO-related complications did not vary significantly.

CONCLUSIONS

In the absence of HCU use, the majority of ECMO patient-hours were spent in normothermia. However, only a minority of patients achieved normothermia for at least 75% of their ECMO course. In-circuit HCUs may be required to maintain high percentages of normothermic time in adult EMCO patients.

Analysis of the airflow features and ventilation efficiency of an Ultra-Clean-Air operating theatre by qDNS simulations and experimental validation

Ultra-Clean-Air (UCA) operating theatres aim to minimise surgical instrument contamination and wound infection through high flow rates of ultra-clean air, reducing the presence of Microbe Carrying Particles (MCPs). This study investigates the airflow patterns and ventilation characteristics of a UCA operating theatre (OT) under standard ventilation system operating conditions, considering both empty and partially occupied scenarios. Utilising a precise computational model, quasi-Direct Numerical Simulations (qDNS) were conducted to delineate flow velocity profiles, energy spectra, distributions of turbulent kinetic energy, energy dissipation rate, local Kolmogorov scales, and pressure-based coherent structures. These results were also complemented by a tracer gas decay analysis following ASHRAE standard guidelines. Simulations showed that contrary to the intended laminar regime, the OT's geometry inherently fosters a predominantly turbulent airflow, sustained until evacuation through the exhaust vents, and facilitating recirculation zones irrespective of occupancy level. Notably, the occupied scenario demonstrated superior ventilation efficiency, a phenomenon attributed to enhanced kinetic energy induced by the additional obstructions. The findings underscore the critical role of UCA-OT design in mitigating MCP dissemination, highlighting the potential to augment the design to optimise airflow across a broader theatre spectrum, thereby diminishing recirculation zones and consequently reducing the propensity for Surgical Site Infections (SSIs). The study advocates for design refinements to harness the turbulent dynamics beneficially, steering towards a safer surgical environment.

A Warm Air Blanket is Superior to a Heated Mattress in Preventing Perioperative Hypothermia in Orthopedic Arthroplasties, a Time-Series Analyses

BACKGROUND

Hypothermia is a common perioperative problem that can lead to severe complications. We evaluated whether a heated mattress (HM) is superior to a warm air blanket (WA) in preventing perioperative hypothermia in patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA).

METHODS

A retrospective cohort study was performed in a teaching hospital and data were collected for all patients undergoing THA or TKA between January 1, 2015 and May 1, 2022. We used logistic and linear regressions to analyze hypothermia occurrence and important complications. Results were adjusted for confounders and time, and was present in all subgroups and after imputation of missing data.

RESULTS

In total, 4,683 of 5,497 patients had information on type of heating. We found more perioperative hypothermia in patients treated with an HM compared to a WA for both THA (odds ratio-adjusted 1.42 [1.0 to 1.6] P = .06) and TKA (odds ratio-adjusted 2.10 [1.5 to 3.0] P < .01). There was no difference in postoperative infections between groups (all between 0.5% and 1.3%). Patients who had an HM significantly stayed longer in the postoperative ward (a mean difference of 4 [TKA] to 6 [THA] minutes, P < .01), but there was no difference in hospital stay.

CONCLUSION

A WA is superior compared to an HM in preventing perioperative hypothermia, with no increased risk of complications. Patients who have an HM stayed longer at the postoperative ward, potentially because of higher hypothermia rates. Therefore, it is suggested to use a WA instead of an HM.

Analysis of the effects of intraoperative warming devices on surgical site infection in elective hip arthroplasty using a large nationwide database

INTRODUCTION

The aim of our study is to analyze the association of usage and type of warming device with the risk of surgical site infection (SSI) in patients who underwent hip arthroplasty, and to analyze the factors that increase the risk of SSI if the warming device is not used.

MATERIALS AND METHODS

This retrospective cross-sectional study identified subjects from data of "Evaluation of the Appropriate Use of Prophylactic Antibiotics". Included patients were defined as those who underwent elective unilateral hip hemiarthroplasty or total hip arthroplasty (THA). Patients were classified into no intraoperative warming device, forced air warming devices, and devices using conduction. Multiple logistic regression analysis was conducted to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs) to assess the association between warming devices and SSI.

RESULTS

A total of 3945 patients met the inclusion criteria. Compared to those who received an intraoperative warming device, the odds of developing SSI were 1.9 times higher in those who did not receive intraoperative warming devices (aOR 1.9; 95% CI 1.1-3.6). The risk of SSI was 2.2 times higher with forced air warming devices compared to devices using conduction but this difference was not statistically significant (aOR 2.2; 95% CI 0.7-6.8). The risk of SSI increased in males (aOR 2.8; 95% CI 1.1-7.2), in patients under 70 years of age (aOR 4.4; 95% CI 1.6-10.4), in patients with a Charlson`s comorbidity index of 2 or higher (aOR 3.3; 95% CI 1.3-8.7), and in patients who underwent THA (aOR 3.8; 95% CI 1.7-8.3) when intraoperative warming devices were not used.

CONCLUSIONS

The use of intraoperative active warming devices is highly recommended to prevent SSI during elective hip arthroplasty. In particular, male patients younger than 70 years, those with a high CCI, and those undergoing THA are at significantly increased risk of SSI if intraoperative active warming devices are not used. Intraoperative warming device using conduction is likely superior to forced air warming device, but further studies are needed to confirm this.

Outpatient-Based High-Volume Liposuction: A Retrospective Review of 310 Consecutive Patients

BACKGROUND

Currently, the definition of large-volume liposuction is the removal of 5 L or more of total aspirate. Higher volumes of lipoaspirate come into consideration with higher BMIs, because more than 5 L is often required to achieve a satisfactory aesthetic result. The boundaries of what lipoaspirate volume is considered safe are based on historical opinion and are constantly in question.

OBJECTIVES

Because to date there have been no scientific data available to support a specific safe maximum volume of lipoaspirate, the authors discuss necessary conditions for safe high-volume lipoaspirate extraction.

METHODS

This retrospective study included 310 patients who had liposuction of ≥5 L over a 30-month period. All patients had 360° liposuction alone or in combination with other procedures.

RESULTS

Patient ages ranged from 20 to 66 with a mean age of 38.5 (SD = 9.3). Average operative time was 202 minutes (SD = 83.1). Mean total aspirate was 7.5 L (SD = 1.9). An average of 1.84 L (SD = 0.69) of intravenous fluids and 8.99 L (SD = 1.47) of tumescent fluid were administered. Urine output was maintained above 0.5 mL/kg/hr. There were no major cardiopulmonary complications or cases requiring blood transfusion.

CONCLUSIONS

High-volume liposuction is safe if proper preoperative, intraoperative, and postoperative protocols and techniques are employed. The authors believe that this bias should be modified and that sharing their experience with high-volume liposuction may help guide other surgeons to incorporate this practice with confidence and safety for better patient outcomes.

LEVEL OF EVIDENCE: 3

Enhanced recovery after surgery (ERAS) protocols for total joint replacement surgery

The enhanced recovery after surgery (ERAS) protocols are a comprehensive therapeutic approach that prioritizes the well-being of patients. It encompasses several aspects such as providing sufficient nutritional support, effectively managing pain, ensuring appropriate fluid management and hydration, and promoting early mobilization after surgery. The advent of ERAS theory has led to a shift in focus within modern ERAS protocols. At present, ERAS protocols emphasize perioperative therapeutic strategies employed by surgeons and anesthesiologists, as well as place increased importance on preoperative patient education, interdisciplinary collaboration, and the enhancement of patient satisfaction and clinical outcomes. This editorial highlights the application of ERAS protocols in the current context of total joint replacement surgery.

Are Intra-operative Forced Air Warming Devices a Possible Source for Contamination During Hand Surgery?

Background Forced air warming (FAW) devices are routinely utilized in operating rooms for patient temperature control. However, there have been some controversy and conflicting evidence on whether they are a possible source of surgical site infections (SSIs) and contamination. Methods A total of 144 petri dishes were randomized to either a control or experimental group (72 in each group). Each trial consisted of six petri dishes in three locations (floor, table, and operative limb). Two dishes at each location were closed sequentially at one hour, two hours, and three hours. Two control and two experimental trials were performed in two separate operating suites with two different FAW devices. The petri dishes were then analyzed for growth for 48 hours. Two culture swabs from each FAW device hose were obtained and analyzed. Results None of the culture swabs analyzed showed any growth on blood or chocolate agar culture media. There was no significant difference in bacterial colony-forming units per cubic meter (CFU/m3) air between the trial and control groups in each location at one hour of exposure. At two hours of exposure, there was a significantly higher bacterial CFU/m3 air in the experimental group in the operative limb. At three hours of exposure, there was a significantly higher bacterial CFU/m3 air in the experimental group on the floor. However, overall, there was no difference in bacterial CFU/m3 air in both study groups at different times of exposure, incubation, or location. Conclusion Our study was unable to identify any statistically significant risk of contamination associated with the use of FAW devices. However, our study design was limited due to the absence of operating room staff during testing. For this reason, we recommend further research into this topic with the use of an active operating room, which includes simulated movement from the surgeon, anesthesia, scrub technician, nursing, and any other operating room staff who may be present during a real operation.

Key Elements of Enhanced Recovery after Total Joint Arthroplasty: A Reanalysis of the Enhanced Recovery after Surgery Guidelines

Recent guidelines have produced a consensus statement for perioperative care in hip and knee replacement. However, there is still a need for reanalysis of the evidence and recommendations. Therefore, we retrieved and reanalyzed the evidence of each recommended components of enhanced recovery after surgery (ERAS) based on the guidelines of total joint arthroplasty. For each one, we included for the highest levels of evidence and those systematic reviews and meta-analyses were preferred. The full texts were analyzed and the evidence of all components were summarized. We found that most of the recommended components of ERAS are supported by evidence, however, the implementation details of each recommended components need to be further optimized. Therefore, implementation of a full ERAS program may maximize the benefits of our clinical practice but this combined effect still needs to be further determined.

Innovation for infection prevention and control-revisiting Pasteur's vision

Louis Pasteur has long been heralded as one of the fathers of microbiology and immunology. Less known is Pasteur's vision on infection prevention and control (IPC) that drove current infection control, public health, and much of modern medicine and surgery. In this Review, we revisited Pasteur's pioneering works to assess progress and challenges in the process and technological innovation of IPC. We focused on Pasteur's far-sighted conceptualisation of the hospital as a reservoir of microorganisms and amplifier of transmission, aseptic technique in surgery, public health education, interdisciplinary working, and the protection of health services and patients. Examples from across the globe help inform future thinking for IPC innovation, adoption, scale up and sustained use.

The Utility of Perioperative Products for the Prevention of Surgical Site Infections in Total Knee Arthroplasty and Lower Extremity Arthroplasty: A Systematic Review

Surgical site infections (SSIs) are among the most prevalent and devastating complications following lower extremity total joint arthroplasty (TJA). Strategies to reduce the rates can be divided into preoperative, perioperatives, and postoperative measures. A multicenter trial is underway to evaluate the efficacy of implementing a bundled care program for SSI prevention in lower extremity TJA including: (1) nasal decolonization; (2) surgical skin antisepsis; (3) antimicrobial incise draping; (4) temperature management; and (5) negative-pressure wound therapy for selected high-risk patients. The purposes of this systematic review were to provide a background and then to summarize the available evidence pertaining to each of these SSI-reduction strategies with special emphasis on total knee arthroplasty. A systematic review of the literature was conducted in accordance with the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement guidelines. Five individual literature searches were performed to identify studies evaluating nasal decolonization temperature management, surgical skin antisepsis, antimicrobial incise draping, and negative-pressure wound therapy. The highest level of evidence reports was used in each product review, and if there were insufficient arthroplasty papers on the particular topic, then papers were further culled from the surgical specialties to form the basis for the review. There was sufficient literature to assess all of the various prophylactic and preventative techniques. All five products used in the bundled program were supported for use as prophylactic agents or for the direct reduction of SSIs in both level I and II studies. This systematic review showed that various pre-, intra-, and postoperative strategies are efficacious in decreasing the risks of SSIs following lower extremity TJA procedures. Thus, including them in the armamentarium for SSI-reduction strategies for hip and knee arthroplasty surgeons should decrease the incidence of infections. We expect that the combined use of these products in an upcoming study will support these findings and may further enhance the reduction of total knee arthroplasty SSIs in a synergistic manner.

Potential sources of operating room air contamination: a preliminary study

BACKGROUND

The Neptune® surgical suction system (NSSS) and the Bair Hugger® (BH) forced-air warmer both discharge filtered exhaust or heated air into the operating room (OR), often in close proximity to a surgical site.

AIM

To assess the effectiveness of this filtration, we examined the quantity and identity of microbial colonies emitted from their output ports compared with those obtained from circulating air entering the OR.

METHODS

Air samples were collected from each device using industry-standard sampling devices in which a measured volume of air is impacted on to a blood agar plate at a controlled flow rate. Twelve ORs were studied. Sample plates were incubated for one week per study protocol, then interpreted for colony counts and sent for species identification.

FINDINGS

The average colony count from the NSSS exhaust was not significantly different from that obtained from room air samples, however the average count from the BH output was significantly higher (P=0.0086) than room air. Genetic identification profiles revealed the presence of environmental or commensal organisms that differed depending on the source. High variability in colony counts from both devices suggests that certain NSSS and BH devices could be significant sources of OR air contamination.

CONCLUSIONS

Our study showed that the BH patient warming device could be a source of airborne microbial contamination in the OR and that individual BH and NSSS units exhibit a higher output of microbial cfu than would be expected compared with incoming room air. We make simple suggestions on ways to mitigate these risks.

Impact of air-conditioner outlet layout on the upward airflow induced by forced air warming in operating rooms

BACKGROUND

Previously, we found that an upward air current in the head area, induced by forced air warming (FAW), was completely counteracted by downward laminar airflow. However, this study did not include any consideration of the air-conditioner outlet layout (ACOL); hence, its impact remains unclear.

METHODS

This study was performed in 2 operating rooms (ORs)-ISO classes 5 and 6, which are denoted as OR-5 and OR-6, respectively. Both ORs have distinct ACOLs. The cleanliness, or the number or ratio of shifting artificial particles was evaluated.

RESULTS

During the first 5 minutes after particles generation, significantly more particles shifted into the surgical field in OR-5 when compared to OR-6 (13,587 [4,341-15,913] and 106 [41-338] particles/cubic foot, P < .0001). Notably, FAW did not increase the number of shifting particles in OR-6. The laminar airflow system fully counteracted the upward airflow caused by FAW in OR-6, where the ACOL covered the operating bed. However, this did not occur in OR-5, where the ACOL did not fully cover the operating bed.

CONCLUSIONS

Regardless of cleanliness ability of OR, an ACOL that fully covers the operating bed can prevent upward airflow in the head area and reduce the number of artificial particles shifting into the surgical field, which are typically caused by FAW.

Prevention of infection in primary THA and TKA

Rates of peri-prosthetic joint infection (PJI) in primary total hip and total knee arthroplasty range between 0.3% and 1.9%, and up to 10% in revision cases. Significant morbidity is associated with this devastating complication, the economic burden on our healthcare system is considerable, and the personal cost to the affected patient is immeasurable.

The risk of surgical site infection (SSI) and PJI is related to surgical factors and patient factors such as age, body mass index (BMI), co-morbidities, and lifestyle. Reducing the risk of SSI in primary hip and knee arthroplasty requires a multi-faceted strategy including pre-operative patient bacterial decolonization, screening and avoidance of anaemia, peri-operative patient warming, skin antisepsis, povidone-iodine wound lavage, and anti-bacterial coated sutures.

This article also considers newer concepts such as the influence of bearing surfaces on infection risk, as well as current controversies such as the potential effects of blood transfusion, laminar flow, and protective hoods and suits, on infection risk.

Cite this article: EFORT Open Rev 2020;5:604-613. DOI: 10.1302/2058-5241.5.200004

Sources of contamination in the operating room: A fluorescent particle powder study

This study utilized fluorescent particle powder to investigate 2 potential sources of sterile field contamination in the operating room (OR): forced-air warming blankets and OR light manipulation. In part 1, sterile draping for knee replacement surgery was performed on a mannequin in a sterile OR, comparing field contamination with the forced-air warming on versus off during draping. In part 2, OR lights coated with fluorescent powder were manipulated over a sterile field. Proper operation of these devices may reduce the particle burden on the surgical field.

Protocol-driven prevention of perioperative hypothermia in the pediatric neurosurgical population

OBJECTIVE

Perioperative hypothermia (PH) is a preventable, pathological, and iatrogenic state that has been shown to result in increased surgical blood loss, increased surgical site infections, increased hospital length of stay, and patient discomfort. Maintenance of normothermia is recommended by multiple surgical quality organizations; however, no group yet provides an ergonomic, evidence-based protocol to reduce PH for pediatric neurosurgery patients. The authors' aim was to evaluate the efficacy of a PH prevention protocol in the pediatric neurosurgery population.

METHODS

A prospective, nonrandomized study of 120 pediatric neurosurgery patients was performed. Thirty-eight patients received targeted warming interventions throughout their perioperative phases of care (warming group-WG). The remaining 82 patients received no extra warming care during their perioperative period (control group-CG). Patients were well matched for age, sex, and preparation time intraoperatively. Hypothermia was defined as < 36°C. The primary outcome of the study was maintenance of normothermia preoperatively, intraoperatively, and postoperatively.

RESULTS

WG patients were significantly warmer on arrival to the operating room (OR) and were 60% less likely to develop PH (p < 0.001). Preoperative forced air warmer use both reduced the risk of PH at time 0 intraoperatively and significantly reduced the risk of any PH intraoperatively (p < 0.001). All patients, regardless of group, experienced a drop in core temperature until a nadir occurred at 30 minutes intraoperatively for the WG and 45 minutes for the CG. At every time interval, from preoperatively to 120 minutes intraoperatively, CG patients were between 2 and 3 times more likely to experience PH (p < 0.001). All patients were warm on arrival to the postanesthesia care unit regardless of patient group.

CONCLUSIONS

Preoperative forced air warmer use significantly increases the average intraoperative time 0 temperature, helping to prevent a fall into PH at the intraoperative nadir. Intraoperatively, a strictly and consistently applied warming protocol made intraoperative hypothermia significantly less likely as well as less severe when it did occur. Implementation of a warming protocol necessitated only limited resources and an OR culture change, and was well tolerated by OR staff.

Editorial Commentary: Just Getting Warmed Up: Risks, Benefits, and Economics of Active Warming Devices

Efforts to maintain normothermia should be a part of every patient's perioperative care. Risks, benefits, and economic implications should be considered when deciding how to use active warming devices for orthopaedic surgery. The Centers for Medicare & Medicaid Services has implemented economic incentives and penalties driving hospitals to invest in active warming devices, including forced-air warmers and resistive heating devices. Even though forced-air warmers and resistive heating blankets are likely to statistically improve patient temperatures, they may not be worth the additional cost for shorter, less invasive, elective arthroscopic surgeries. In addition, recent research demonstrates minimal clinically significant differences between these 2 types of devices. Concern regarding possible increased risk of surgical-site contamination with forced-air warmers warrants further study but, again, is unlikely clinically relevant to arthroscopic cases, and proper staff training and warming equipment routine maintenance could minimize patient risk.

Consensus statement for perioperative care in total hip replacement and total knee replacement surgery: Enhanced Recovery After Surgery (ERAS®) Society recommendations

Background and purpose - There is a large volume of heterogeneous studies across all Enhanced Recovery After Surgery (ERAS®) components within total hip and total knee replacement surgery. This multidisciplinary consensus review summarizes the literature, and proposes recommendations for the perioperative care of patients undergoing total hip replacement and total knee replacement with an ERAS program.Methods - Studies were selected with particular attention being paid to meta-analyses, randomized controlled trials, and large prospective cohort studies that evaluated the efficacy of individual items of the perioperative treatment pathway to expedite the achievement of discharge criteria. A consensus recommendation was reached by the group after critical appraisal of the literature.Results - This consensus statement includes 17 topic areas. Best practice includes optimizing preoperative patient education, anesthetic technique, and transfusion strategy, in combination with an opioid-sparing multimodal analgesic approach and early mobilization. There is insufficient evidence to recommend that one surgical technique (type of approach, use of a minimally invasive technique, prosthesis choice, or use of computer-assisted surgery) over another will independently effect achievement of discharge criteria.Interpretation - Based on the evidence available for each element of perioperative care pathways, the ERAS® Society presents a comprehensive consensus review, for the perioperative care of patients undergoing total hip replacement and total knee replacement surgery within an ERAS® program. This unified protocol should now be further evaluated in order to refine the protocol and verify the strength of these recommendations.

Laminar flow does not affect risk of prosthetic joint infection after primary total knee replacement in Asian patients

BACKGROUND

The role of laminar flow (LAF) is contradictory with several studies failing to replicate risk reduction. The 2016 World Health Organization guidelines identified this lack of good comparative studies.

AIM

To analyse the use of LAF and the incidence of prosthetic joint infections (PJIs) in Asian patients undergoing total knee replacement (TKR).

METHODS

Patients who underwent standard cemented posterior-stabilized TKR from 2004 to 2014 were reviewed from a prospectively collected single-surgeon database. Revision, traumatic and/or inflammatory cases were excluded. The type of airflow used was identified. The technique and surgical protocol for all procedures were similar. Tourniquets and inserted drains were routinely used. Patellar resurfacing was not performed. Patients were followed up at the outpatient clinics at regular intervals up to two years. At each visit, the patient was assessed for the occurrence of PJI.

FINDINGS

Of the 1028 procedures, 453 (44.1%) were performed in an LAF operating theatre (OT) whereas 575 (55.9%) were performed in a non-LAF OT. There were no significant differences between the two groups in terms of age, gender, or side of procedure. The overall incidence of PJI was 0.6% (N = 6). Three (50%) occurred in an LAF OT whereas three (50%) occurred in a non-LAF OT. This was not statistically significant.

CONCLUSION

Laminar flow systems are costly to procure and maintain. With modern aseptic techniques, patient optimization, and use of prophylactic antibiotics, laminar flow does not appear to further reduce risk of PJI in Asian patients after TKR.

Comparing Forced-Air to Resistive-Polymer Warming for Perioperative Temperature Management: A Retrospective Study

PURPOSE

Compare perioperative temperature management between forced-air warming (FAW) and resistive-polymer heating blankets (RHBs).

DESIGN

A retrospective, quasi-experimental study.

METHODS

Retrospective data analysis of nonspine orthopedic cases (N = 426) over a one-year period including FAW (n = 119) and RHBs (n = 307).

FINDINGS

FAW was associated with a significantly higher final intraoperative temperature (P = .001, d = 0.46) than the RHB. The incidence of hypothermia was not found to be significantly different at the end (P = .102) or anytime throughout surgery (P = .270). Of all patients who started hypothermic, the FAW group had a lower incidence of hypothermia at the end of surgery (P = .023).

CONCLUSIONS

FAW was associated with higher final temperatures and a greater number of normothermic patients than RHBs. However, no causal relationship between a warming device and hypothermia incidence should be assumed.

Reducing Implant Infection in Orthopaedics (RIIiO): Results of a pilot study comparing the influence of forced air and resistive fabric warming technologies on postoperative infections following orthopaedic implant surgery

BACKGROUND

Active warming during surgery prevents perioperative hypothermia but the effectiveness and postoperative infection rates may differ between warming technologies.

AIM

To establish the recruitment and data management strategies needed for a full trial comparing postoperative infection rates associated with forced air warming (FAW) versus resistive fabric warming (RFW) in patients aged >65 years undergoing hemiarthroplasty following fractured neck of femur.

METHODS

Participants were randomized 1:1 in permuted blocks to FAW or RFW. Hypothermia was defined as a temperature of <36°C at the end of surgery. Primary outcomes were the number of participants recruited and the number with definitive deep surgical site infections.

FINDINGS

A total of 515 participants were randomized at six sites over a period of 18 months. Follow-up was completed for 70.1%. Thirty-seven participants were hypothermic (7.5% in the FAW group; 9.7% in the RFW group). The mean temperatures before anaesthesia and at the end of surgery were similar. For the primary clinical outcome, there were four deep surgical site infections in the FAW group and three in the RFW group. All participants who developed a postoperative infection had antibiotic prophylaxis, a cemented prosthesis, and were operated under laminar airflow; none was hypothermic. There were no serious adverse events related to warming.

CONCLUSION

Surgical site infections were identified in both groups. Progression from the pilot to the full trial is possible but will need to take account of the high attrition rate.

The effectiveness of air-free warming systems on perioperative hypothermia in total hip and knee arthroplasty: A systematic review and meta-analysis

BACKGROUND

Perioperative hypothermia is a common and serious complication during surgery. Different warming systems are used to prevent perioperative hypothermia. However, there have been no previous meta-analyses of the effectiveness of air-free warming systems on perioperative hypothermia in patients undergoing joint arthroplasty.

METHODS

We systematically searched PubMed, EMBASE, Cochrane Library, and China National Knowledge Infrastructure (CNKI) databases to collect randomized controlled trials (RCTs) from inception to August 2018. These RCTs compared the effects of air-free warming with forced-air (FA) warming system in patients undergoing joint arthroplasty. Postoperative temperature, core temperature during surgery, thermal comfort, blood loss and incidence of shivering and hypothermia were analyzed.

RESULTS

A total of 287 patients from 6 clinical studies were included in the analysis. In summary, there was no significant difference in the postoperative temperature (WMD -0.043, 95% CI -0.32 to 0.23, P = .758) between the air-free warming and FA warming groups. No statistical difference (WMD 0.058, 95% CI -0.10 to 0.22, P = .475) was found in core temperatures at 0 minutes during surgery between the air-free warming and FA warming groups. Furthermore, there was no statistical difference in thermal comfort, blood loss or incidence of shivering and hypothermia between the air-free warming and FA warming groups.

CONCLUSIONS

Air-free warming system was as effective as FA warming system in patients undergoing joint arthroplasty.

Association between perioperative hypothermia and surgical site infection: A meta-analysis

BACKGROUND

A majority of reports in the past decade have demonstrated that perioperative hypothermia increases susceptibility to surgical site infection (SSI). However, in recent years, an increasing number of studies did not find an association between hypothermia and the risk of SSI. These contradictory results have given rise to a conflicting issue on whether perioperative hypothermia is associated with SSI risk in surgical patients.

METHODS

We examined the association between perioperative hypothermia and SSI incidence and then integrated available evidence by searching the databases, such as PubMed, Web of Science, Embase, and Cochrane library for potential papers from inception to April 2018. We included studies that reported original data or odds ratio (OR) with 95% confidence intervals (CIs) of the associations. Using fixed-effects models combined the OR with 95% CIs, randomized controlled trials and observational studies were analyzed, respectively, and cohort studies were further analyzed. Sensitivity analyses were performed by omitting each study iteratively, and publication bias was detected using Begg's tests.

RESULTS

We screened 384 studies, and identified 8 eligible studies, including 2 randomized controlled trials and 6 observational studies (1 case-control study and 5 cohort studies). The pooled OR results in the randomized controlled studies showed that perioperative hypothermia could increase the risk of SSI without heterogeneity (OR, 1.60; 95% CI, 1.14-2.23; I = 0.0%, P = .845). The fixed-effect meta-analysis indicated no association between perioperative hypothermia and SSI risk in observational studies (OR, 0.98; 95% CI, 0.96-1.01; I = 53.2%, P = .058). Furthermore, cohort studies were performed to pool OR by using the fixed-effect model, and the incorporated results also suggested a similar relationship (OR, 1.13; 95% CI, 0.97-1.33; I = 46.4%, P = .113).

CONCLUSION

The meta-analysis suggests that perioperative hypothermia is not associated with SSI in surgical patients. However, the 8 eligible studies were mostly cohort studies. Thus, further randomized controlled trials are required to confirm this finding.

Laminar Air Flow Handling Systems in the Operating Room

BACKGROUND

Surgical site infection is associated with a substantial healthcare burden and remains one of the most challenging complications to treat. Airborne particles carrying contaminating micro-organisms are responsible for the majority of these infections.

METHODS

Various operating theater ventilatory systems have been developed to prevent direct airborne bacterial inoculation of the surgical wound. Laminar air flow uses positive pressure air currents through filtration units to direct air streams away from the operative field in order to create an ultraclean zone around the operative site.

DISCUSSION

Early studies reported lower infection rates with laminar air flow and therefore it became the accepted standard for implant-related surgery. However, more recent evidence has questioned its clinical importance. The purpose of this article is to review contemporary laminar air flow handling systems and the current evidence behind their use.

Forced-Air Warming and Resistive Heating Devices. Updated Perspectives on Safety and Surgical Site Infections

Introduction: Perioperative hypothermia is one of the most common phenomena seen among surgical patients, leading to numerous adverse outcomes such as intraoperative blood loss, cardiac events, coagulopathy, increased hospital stay and associated costs. Forced air warming (FAW) and resistive heating (RH) are the two most commonly used and widely studied devices to prevent perioperative hypothermia. The effect of FAW on operating room laminar flow and surgical site infection is unclear and we initiated an extensive literature search in order to get a scientific insight of this aspect.

Material and Methods: The literature search was conducted using the Medline search engine, PubMed, Cochrane review, google scholar, and OSU library.

Results: Out of 92 Articles considered initially for review we selected a total of 73 relevant references. Currently there is no robust evidence to support that FAW can increase SSIs. In addition, both of the two warming devices present safety problems.

Conclusion: As unbiased independent reviewers, we advise clinicians to weigh the risks and benefits when using either one of these devices; no change in the current practice is necessary until further data emerges.

Reducing Implant Infection in Orthopaedics (RIIiO): a pilot study for a randomised controlled trial comparing the influence of forced air versus resistive fabric warming technologies on postoperative infection rates following orthopaedic implant surgery in adults

Background

Approximately 70,000 to 75,000 proximal femoral fracture repairs take place in the UK each year. Hemiarthroplasty is the preferred treatment for adults aged over 60 years. Postoperative infection affects up to 3% of patients and is the single most common reason for early return to theatre. Ultraclean ventilation was introduced to help mitigate the risk of infection, but it may also contribute to inadvertent perioperative hypothermia, which itself is a risk for postoperative infection. To counter this, active intraoperative warming is used for all procedures that take 30 min or more. Forced air warming (FAW) and resistive fabric warming (RFW) are the two principal techniques used for this purpose; they are equally effective in prevention of inadvertent perioperative hypothermia, but it is not known which is associated with the lowest infection rates. Deep surgical site infection doubles operative costs, triples investigation costs and quadruples ward costs. The Reducing Implant Infection in Orthopaedics (RIIiO) study seeks to compare infection rates with FAW versus RFW after hemiarthroplasty for hip fracture. A cost-neutral intervention capable of reducing postoperative infection rates would likely lead to a change in practice, yield significant savings for the health economy, reduce overall exposure to antibiotics and improve outcomes following hip fracture in the elderly. The findings may be transferable to other orthopaedic implant procedures and to non-orthopaedic surgical specialties.

Methods

RIIiO is a parallel group, open label study randomising hip fracture patients over 60 years of age who are undergoing hemiarthroplasty to RFW or FAW. Participants are followed up for 3 months. Definitive deep surgical site infection within 90 days of surgery, the primary endpoint, is determined by a blinded endpoint committee.

Discussion

Hemiarthroplasty carries a risk of deep surgical site infection of approximately 3%. In order to provide 90% power to demonstrate an absolute risk reduction of 1%, using a 5% significance level, a full trial would need to recruit approximately 8630 participants. A pilot study is being conducted in the first instance to demonstrate that recruitment and data management strategies are appropriate and robust before embarking on a large multi-centre trial.

Trial registration

ISRCTN, ISRCTN74612906. Registered on 27 February 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-3011-y) contains supplementary material, which is available to authorized users.

High Efficiency Particulate Air Filters Do Not Affect Acute Infection Rates During Primary Total Joint Arthroplasty Using Forced Air Warmers

BACKGROUND

Studies have suggested that forced-air warmers (FAWs) increase contamination of the surgical site. In response, FAWs with high efficiency particulate air filters (FAW-HEPA) were introduced. This study compared infection rates following primary total joint arthroplasty (TJA) using FAW and FAW-HEPA.

METHODS

Primary TJA patients at a single healthcare system were retrospectively reviewed. A total of 5405 THA (n = 2419) and TKA (n = 2986) consecutive cases in 2013 and 2015 were identified. Patients in 2013 (n = 2792) had procedures using FAW, while FAW-HEPA was used in 2015 (n = 2613). The primary outcome was overall infection rate within 90-days. Sub-categorization of infections as periprosthetic joint infection (PJI) or surgical site infection (SSI) was also conducted. PJI was defined as reoperation with arthrotomy or meeting Musculoskeletal Infection Society (MSIS) criteria. SSI was defined as wound complications requiring antibiotics or irrigation/debridement.

RESULTS

The FAW and FAW-HEPA groups had similar rates of overall infection (1.65% [n = 46] vs 1.61% [n = 42], P > .99), SSI (1.18% [n = 33] vs 0.84% [n = 22], P = .27), and PJI (0.47% [n = 13] vs 0.77% [n = 20], P = .22). Regression models did not show FAW to be an independent risk factor for increased overall infection (odds ratio [OR] 1.00, 95% confidence interval [CI] 0.65-1.57, P = .97), SSI (OR 1.47, 95% CI 0.83-2.58, P = .18), or PJI (OR 0.53, 95% CI 0.25-1.13, P = .09).

CONCLUSION

FAW were not correlated with a higher risk of overall infection, SSI, or PJI during TJA when compared to FAW-HEPA devices.

What is the incidence of inadvertent hypothermia in elderly hip fracture patients and is this associated with increased readmissions and mortality?

Background

Globally the incidence of fragility hip fractures is rising with increasingly elderly and co-morbid patients. These injuries are associated with a high morbidity and mortality.

Aims

This clinical study's primary outcome is to establish the rate of operative inadvertent hypothermia (<36 °C) in elderly hip fracture patients (>65 years old). We also aimed to identify risk factors and outcomes in patients with inadvertent hypothermia.

Patients and Methods

A single centre, retrospective study of 929 hip fracture patients managed operatively between June 2015 and July 2017 was conducted. Patients' demographic, anaesthetic and surgical variables were analysed together with outcomes for length of stay (LoS), 30-day re-admissions, and 30-day mortality.

Results

Overall rates of inadvertent hypothermia in elderly hip fracture patients undergoing surgery were 10%, with increasing age (p = 0.006) and pre-operative hypothermia (p < 0.0001) as risk factors. Patient's hypothermic pre-operatively compared with normothermic patients were 1.9 times more likely to be <36 °C on leaving theatre. There was a trend towards a higher 30-day mortality (χ²(1) = 2.818, p = 0.093), and a significantly higher mortality in patients undergoing SHS (p = 0.03). No survival differences for LoS were observed between hypothermic and ≥36 °C patients (χ2(1) = 0.069, p = 0.79). 30-day re-admissions were higher in hypothermic patients (χ2(1) = 16.301, p < 0.0001).

Conclusion

Rates of inadvertent hypothermia are high in operatively managed hip fracture patients and are significantly associated with a higher 30-day readmission rate with a trend towards higher 30-day mortality.

Effect of heated-air blanket on the dispersion of squames in an operating room

High-fidelity, predictive fluid flow simulations of the interactions between the rising thermal plumes from forced air warming blower and the ultra-clean ventilation air in an operating room (OR) are conducted to explore whether this complex flow can impact the dispersion of squames to the surgical site. A large-eddy simulation, accurately capturing the spatiotemporal evolution of the flow in 3 dimensions together with the trajectories of squames, is performed for a realistic OR consisting of an operating table (OT), side tables, surgical lamps, medical staff, and a patient. Two cases are studied with blower-off and blower-on together with Lagrangian trajectories of 3 million squames initially placed on the floor surrounding the OT. The large-eddy simulation results show that with the blower-off, squames are quickly transported by the ventilation air away from the table and towards the exit grilles. In contrast, with the hot air blower turned on, the ventilation airflow above and below the OT is disrupted significantly. The rising thermal plumes from the hot air blower drag the squames above the OT and the side tables and then they are advected downwards toward the surgical site by the ventilation air from the ceiling. Temporal history of the number of squames reaching 4 imaginary boxes surrounding the side tables, the OT, and the patient's knee shows that several particles reach these boxes for the blower-on case.

Inadvertent hypothermia in hip and knee total joint arthroplasty

Background

This clinical study aims to establish rates of inadvertent hypothermia (IH) in both primary and revision total hip/knee arthroplasty (THA/TKA and rTHA/rTHA). We postulate differences exist between demographic, surgical and anesthetic variables and outcomes for IH and normothermic patients.

Methods

We conducted a single centre, retrospective study of 2431 total joint arthroplasty (TJA) patients having undergone THA (n = 1096), TKA (n = 1083), rTHA (n = 165) and rTKA (n = 87) from March 2013 to December 2016. Outcomes include length of stay (LOS), 31-day complication rates for thrombotic events and infection and 31-day readmission rates (RR).

Results

Overall rates of IH were 11.7%; with cohort analysis demonstrating rates of 13.2%, 11.2%, 8.3% and 3.9% in THA, TKA, rTHA and rTKA respectively. Patients with body mass index (BMI)<29 kg/m² and undergoing THA were at risk of IH. For all TJA, no difference was observed in 31-day complications (1.6% vs. 2.8%, p = 0.19), 31-day RR (3.3% vs. 4.5%, p = 0.50) or LOS (4.6 ± 2.9 vs. 5.1 ± 4.5, p = 0.11). IH was associated with higher RR for haematoma in TKA (2.9% vs. 0.4%, p = 0.021) and higher deep infection rates in rTHA (20% vs 0%, p = 0.006).

Conclusion

Our study demonstrates a 3.9% to 13.2% rate of IH in TJA, with lower BMI, THA and primary cases as risk factors. We recommend protective steps are taken to maintain patient normothermia in these groups.

Effectiveness of Early Warming With Self-Warming Blankets on Postoperative Hypothermia in Total Hip and Knee Arthroplasty

BACKGROUND

Hypothermia is an important complication in joint arthroplasty. Commonly, forced air warming (FAW) devices are used intraoperatively to maintain body temperature in patients undergoing surgery. However, it is believed that these convective warming systems could increase the risk of deep surgical site infections due to disruption of unidirectional downward laminar airflow. Conductive warming devices have no noticeable effect on ventilation airflow. Nevertheless, the effectiveness of the self-warming (SW) blanket, a novel conductive warming device, on postoperative hypothermia in elective joint arthroplasty is unknown.

PURPOSE

The purpose of this study was to evaluate the effectiveness of early warming with SW blankets in the prevention of postoperative hypothermia in elective total hip (THA) and knee arthroplasty (TKA) compared with FAW devices.

METHODS

Patients who underwent elective THA or TKA between May and June 2014 were assigned in the FAW or SW group. A total of 105 patients were enrolled into the study. In the FAW group, the FAW devices were applied after disinfection of the surgical site. In the SW group, the SW blankets were already applied in the orthopaedic department. The duration of warming with SW blankets before anesthetic induction was documented. The body temperature was measured preoperatively upon arrival in the orthopaedic department and postoperatively upon arrival in the postanesthesia care unit. The patient's body temperature was measured at the tympanic membrane, and hypothermia was defined as a body temperature of less than 35.5°C.

RESULTS

The SW blankets were applied for a median of 86.8 minutes (78.8-94.8) before anesthetic induction. Postoperative hypothermia was observed in 15 (31.3%) and eight (14.0%) patients in the FAW group and the SW group, respectively (p = .029). The median postoperative body temperature was 35.59°C (35.44-35.74) and 35.95°C (35.83-36.06) in the FAW group and the SW group, respectively (p < .001).

CONCLUSION

Early warming with SW blankets was more effective than FAW devices in the prevention of postoperative hypothermia in elective THA and TKA.

A novel thermal compression device for perioperative warming: a randomized trial for feasibility and efficacy

Background

Inadvertent perioperative hypothermia (IPH) leads to surgical complications and increases length of stay. IPH rates are high with the current standard of care, forced air warming (FAW). Our hypothesis is that a prototype thermal compression device that heats the popliteal fossa and soles of the feet, with lower leg compression, increases perioperative temperatures and reduces IPH compared to the current standard of care.

Methods

Thirty six female breast surgery patients, at a tertiary academic hospital, were randomized to the device or intraoperative FAW (stage I) with a further 18 patients randomized to the device with a single heating area only (stage II, popliteal fossa or sole of the feet). Stage I: 37 patients recruited (final 36). Stage II: 18 patients recruited (final 18). Inclusion criteria: general anesthesia with esophageal monitoring for over 30 min, legs available and able to fit the device and no contraindications to leg heating or compression. The intervention was: Stage I: Investigational prototype thermal compression device (full device group) or intraoperative FAW. Stage II: Device with only a single heating location. Primary outcomes were perioperative temperatures and incidence of IPH. Secondary outcomes were local skin temperature, general and thermal comfort scores and presence of perioperative complications, including blood loss.

Results

Mean temperatures in the full device group were significantly higher than the FAW group in the pre-operative (36.7 vs 36.4 °C, p < 0.001), early intraoperative (36.3 vs 35.9 °C, p < 0.001), intraoperative (36.6 vs 36.2 °C, p < 0.001) and postoperative periods (36.8 vs 36.5 °C, p < 0.001). The incidence of IPH in the device group was also significantly lower (16.7% vs 72.0%, p = 0.001). Thermal comfort scores were significantly higher in the full device group and hypothermia associated wound complications were higher in the FAW group.

Conclusions

The thermal compression device is feasible and has efficacy over the FAW. Further studies are recommended to investigate clinically significant outcomes.

Trial registration

clinicaltrials.gov (NCT02155400)

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-017-0395-2) contains supplementary material, which is available to authorized users.

The effect of operating lights on laminar flow

Aims

The interaction between surgical lighting and laminar airflow is poorly understood. We undertook an experiment to identify any effect contemporary surgical lights have on laminar flow and recommend practical strategies to limit any negative effects.

Materials and Methods

Neutrally buoyant bubbles were introduced into the surgical field of a simulated setup for a routine total knee arthroplasty in a laminar flow theatre. Patterns of airflow were observed and the number of bubbles remaining above the surgical field over time identified. Five different lighting configurations were assessed. Data were analysed using simple linear regression after logarithmic transformation.

Results

In the absence of surgical lights, laminar airflow was observed, bubbles were cleared rapidly and did not accumulate. If lights were placed above the surgical field laminar airflow was abolished and bubbles rose from the surgical field to the lights then circulated back to the surgical field. The value of the decay parameter (slope) of the two setups differed significantly; no light (b = -1.589) versus one light (b = -0.1273, p < 0.001). Two lights touching (b = -0.1191) above the surgical field had a similar effect to that of a single light (p = 0. 2719). Two lights positioned by arms outstretched had a similar effect (b = -0.1204) to two lights touching (p = 0.998) and one light (p = 0.444). When lights were separated widely (160 cm), laminar airflow was observed but the rate of clearance of the bubbles remained slower (b = -1.1165) than with no lights present (p = 0.004).

Conclusion

Surgical lights have a significantly negative effect on laminar airflow. Lights should be positioned as far away as practicable from the surgical field to limit this effect. Cite this article: Bone Joint J 2017;99-B:1061–6.

Prevention of Periprosthetic Joint Infection: Examining the Recent Guidelines

BACKGROUND

The global rise in infectious disease has led the Center for Disease Control and Prevention and the World Health Organization to release new guidelines for the prevention of surgical site infection.

METHODS

In this article, we summarize current recommendations based on level of evidence, review unresolved and unaddressed issues, and supplement them with new literature.

RESULTS

Although the guidelines discuss major issues in reducing surgical site infection, many questions remain unanswered.

CONCLUSION

These guidelines will hopefully help in setting a standard of care based on best evidence available and focus investigators on areas where evidence is lacking.

Normothermia in Arthroplasty

BACKGROUND

Since the initial design of surgical theatres, the thermal environment of the operating suite itself has been an area of concern and robust discussion. In the 1950s, correspondence in the British Medical Journal discussed the most suitable design for a surgeon's cap to prevent sweat from dripping onto the surgical field. These deliberations stimulated questions about the effects of sweat-provoking environments on the efficiency of the surgical team, not to mention the effects on the patient. Although these benefits translate to implant-based orthopedic surgery, they remain poorly understood and, at times, ignored.

METHODS

A review and synthesis of the body of literature on the topic of maintenance of normothermia was performed.

RESULTS

Maintenance of normothermia in orthopedic surgery has been proven to have broad implications from bench top to bedside. Normothermia has been shown to impact everything from nitrogen loss and catabolism after hip fracture surgery to infection rates after elective arthroplasty.

CONCLUSION

Given both the physiologic impact this has on patients, as well as a change in the medicolegal environment around this topic, a general understanding of these concepts should be invaluable to all surgeons.

Forced-Air Warming Discontinued: Periprosthetic Joint Infection Rates Drop

Several studies have shown that the waste heat from forced-air warming (FAW) escapes near the floor and warms the contaminated air resident near the floor. The waste heat then forms into convection currents that rise up and contaminate the sterile field above the surgical table. It has been shown that a single airborne bacterium can cause a periprosthetic joint infection (PJI) following joint replacement surgery. We retrospectively compared PJI rates during a period of FAW to a period of air-free conductive fabric electric warming (CFW) at three hospitals. Surgical and antibiotic protocols were held constant. The pooled multicenter data showed a decreased PJI rate of 78% following the discontinuation of FAW and a switch to air-free CFW (n=2034; P=0.002). The 78% reduction in joint implant infections observed when FAW was discontinued suggests that there is a link between the waste FAW heat and PJIs.

Heated wire humidification circuit attenuates the decrease of core temperature during general anesthesia in patients undergoing arthroscopic hip surgery

Background

Intraoperative hypothermia is common in patients undergoing general anesthesia during arthroscopic hip surgery. In the present study, we assessed the effect of heating and humidifying the airway with a heated wire humidification circuit (HHC) to attenuate the decrease of core temperature and prevent hypothermia in patients undergoing arthroscopic hip surgery under general anesthesia.

Methods

Fifty-six patients scheduled for arthroscopic hip surgery were randomly assigned to either a control group using a breathing circuit connected with a heat and moisture exchanger (HME) (n = 28) or an HHC group using a heated wire humidification circuit (n = 28). The decrease in core temperature was measured from anesthetic induction and every 15 minutes thereafter using an esophageal stethoscope.

Results

Decrease in core temperature from anesthetic induction to 120 minutes after induction was lower in the HHC group (–0.60 ± 0.27℃) compared to the control group (–0.86 ± 0.29℃) (P = 0.001). However, there was no statistically significant difference in the incidence of intraoperative hypothermia or the incidence of shivering in the postanesthetic care unit.

Conclusions

The use of HHC may be considered as a method to attenuate intraoperative decrease in core temperature during arthroscopic hip surgery performed under general anesthesia and exceeding 2 hours in duration.

Comparison of forced-air and water-circulating warming for prevention of hypothermia during transcatheter aortic valve replacement

Introduction

Transcatheter Aortic Valve Replacement (TAVR) procedures at our institution were complicated by perioperative hypothermia despite use of the standard of care forced-air convective warming device (the BairHugger, Augustine Medical Inc, Eden Prairie, MN, USA). To remedy this problem, we initiated a quality improvement process that investigated the use of a conductive warm water-circulating device (the Allon ThermoWrap, Menen Medical Corporation, Trevose, PA, USA), and hypothesized that it would decrease the incidence of perioperative hypothermia.

Methods

We compared two different intraoperative warming devices using a historic control. We retrospectively reviewed intraoperative records of 80 TAVRs between 6/2013 and 6/2015, 46 and 34 of which were done with the forced-air and water-circulating devices, respectively. Continuous temperature data obtained from pulmonary artery catheter, temperature upon arrival to cardiothoracic ICU (CTU), age, BSA, height, and BMI were compared.

Results

Patients warmed with both devices were similar in terms of demographic characteristics. First recorded intraoperative temperature (mean 36.26 ± SD 0.61 vs. 35.95 ± 0.46°C, p = 0.02), lowest intraoperative temperature (36.01 ± 0.58 vs. 34.89 ± 0.76°C, p<0.001), temperature at the end of the procedure (36.47 ± 0.51 vs. 35.17 ± 0.75°C, p<0.001), and temperature upon arrival to the CTU (36.35 ± 0.44 vs. 35.07 ± 0.78°C, p<0.001) were significantly higher in the water-circulating group as compared to the forced-air group.

Conclusion

A quality improvement process led to selection of a new warming device that virtually eliminated perioperative hypothermia at our institution. Patients warmed with the new device were significantly less likely to experience intraoperative hypothermia and were significantly more likely to be normothermic upon arrival to the CTU.

Safety and efficacy of resistive polymer versus forced air warming in total joint surgery

Background

Forced-air warming is used as a mechanism to prevent hypothermia and adverse outcomes associated with hypothermia among patients undergoing surgery. Patient safety in healthcare includes the use of devices and technology that minimize potential adverse events to patients. The present study sought to compare the capabilities of patient warming between two different devices that use different mechanisms of warming: forced-air warming and non-air warming.

Methods

One hundred twenty patients undergoing total hip or total knee arthroplasty received patient warming via a forced warming device or non-air warming fabric conductive material. The project was part of a quality improvement initiative to identify warming devices effective in maintaining normothermic patient core temperatures during orthopedic surgery.

Results

Forced-air warming and non-air warming achieved similar results in maintaining the core temperature of patients undergoing total knee or hip arthroplasty. No adverse events were reported in either group. Operating room staff observed that the non-air warming device was less noisy and appreciated the disposable covers that could be changed after each surgical case.

Conclusions

These findings demonstrate that hypothermia is achieved by both forced-air and non-forced air warming devices among total knee and hip arthroplasty patients. The potential for airflow disruption is present with the forced-air warming device and does not exist with the non-forced air device. The disruption of laminar airflow may be associated with surgical site infections. The disposable covers used to protect the device and patient have potential implications for surgical site infection. Quality improvement efforts aimed to enhance patient safety should include the implementation of healthcare equipment with the least known or suspected risk.

Prevention of periprosthetic joint infection: new guidelines

The World Health Organization (WHO) and the Centre for Disease Control and Prevention (CDC) recently published guidelines for the prevention of surgical site infection. The WHO guidelines, if implemented worldwide, could have an immense impact on our practices and those of the CDC have implications for healthcare policy in the United States. Our aim was to review the strategies for prevention of periprosthetic joint infection in light of these and other recent guidelines. Cite this article: Bone Joint J 2017;99-B(4 Supple B):3-10.

Airborne bacterial contamination during orthopedic surgery: A randomized controlled pilot trial

STUDY OBJECTIVE

Several factors such as lack of unidirectional, turbulent free laminar airflow, duration of surgery, patient warming system, or the number of health professionals in the OR have been shown or suspected to increase the number of airborne bacteria. The objective of this study was to perform a multivariate analysis of bacterial counts in the OR in patients during minor orthopedic surgery.

DESIGN

Prospective, randomized pilot study.

SETTING

Medical University of Vienna, Austria.

PATIENTS

Eighty patients undergoing minor orthopedic surgery were included in the study.

INTERVENTIONS

Surgery took place in ORs with and without a unidirectional turbulent free laminar airflow system, patients were randomized to warming with a forced air or an electric warming system.

MEASUREMENT

The number of airborne bacteria was measured using sedimentation agar plates and nitrocellulose membranes at 6 standardized locations in the OR.

MAIN RESULTS

The results of the multivariate analysis showed, that the absence of unidirectional turbulent free laminar airflow and longer duration of surgery increased bacterial counts significantly. The type of patient warming system and the number of health professionals had no significant influence on bacterial counts on any sampling site.

CONCLUSION

ORs with unidirectional turbulent free laminar airflow, and a reduction of surgery time decreased the number of viable airborne bacteria. These factors may be particularly important in critical patients with a high risk for the development of surgical site infections.