Laminar flow reduces cases of surgical site infections in vascular patients

From basic research to clinical practice: The impact of laminar airflow filters on surgical site infection in vascular surgery

BACKGROUND

Laminar airflow filters have been suggested as a potential preventive factor for surgical site infections, given their ability to reduce the airborne microbiological load. However, their role is still unclear, and evidence regarding vascular surgery patients is scarce. Our aim was to assess the impact of laminar-airflow filters on surgical site infections.

METHODS

This single-centre retrospective cohort study was conducted with vascular surgery patients who underwent arterial vascular intervention through a groin incision between July 2018 and July 2019 (turbulent airflow cohort) and July 2020 and July 2021 (laminar airflow cohort). Data were prospectively collected from electronic medical files. We estimated the cumulative incidence of surgical site infections and its 95% confident interval (95%CI). A propensity score matching analysis was performed.

RESULTS

We included 200 patients, 78 in the turbulent airflow cohort and 122 in the laminar airflow cohort. The cumulative incidence was 15.4% (12/78; 95%CI: 9.0-25.0%) in the turbulent-airflow cohort and 14.8% (18/122; 95%CI: 9.5 -22.1%) in the laminar-airflow cohort (p-value: 1.00). The propensity score matching yielded a cumulative incidence of surgical site infection of 13.9% (10/72) with turbulent airflow and 12.5% (9/72) with laminar airflow (p-value: 1.00). Risk factors associated with infection were chronic kidney disease (OR 2.70; 95%CI: 1.14-6.21) and a greater body mass index (OR 1.47; 95%CI: 1.01-2.14).

CONCLUSION

Laminar airflow filters were associated with a non-significant reduction of surgical site infections. Further research is needed to determine its usefulness and cost-effectiveness. Surgical site infection incidence was associated with chronic kidney disease and a greater body mass index. Hence, efforts should be made to optimize the body mass index before surgery and prevent chronic kidney disease in patients with known arterial disease.

Effect of unidirectional airflow ventilation on surgical site infection in cardiac surgery: environmental impact as a factor in the choice for turbulent mixed air flow

BACKGROUND

Surgical site infection (SSI) in the form of postoperative deep sternal wound infection (DSWI) after cardiac surgery is a rare, but potentially fatal, complication. In addressing this, the focus is on preventive measures, as most risk factors for SSI are not controllable. Therefore, operating rooms are equipped with heating, ventilation and air conditioning (HVAC) systems to prevent airborne contamination of the wound, either through turbulent mixed air flow (TMA) or unidirectional air flow (UDAF).

AIM

To investigate if the risk for SSI after cardiac surgery was decreased after changing from TMA to UDAF.

METHODS

This observational retrospective single-centre cohort study collected data from 1288 patients who underwent open heart surgery over 2 years. During the two study periods, institutional SSI preventive measures remained the same, with the exception of the type of HVAC system that was used.

FINDINGS

Using multi-variable logistic regression analysis that considered confounding factors (diabetes, obesity, duration of surgery, and re-operation), the hypothesis that TMA is an independent risk factor for SSI was rejected (odds ratio 0.9, 95% confidence interval 0.4-1.8; P>0.05). It was not possible to demonstrate the preventive effect of UDAF on the incidence of SSI in patients undergoing open heart surgery when compared with TMA.

CONCLUSION

Based on these results, the use of UDAF in open heart surgery should be weighed against its low cost-effectiveness and negative environmental impact due to high electricity consumption. Reducing energy overuse by utilizing TMA for cardiac surgery can diminish the carbon footprint of operating rooms, and their contribution to climate-related health hazards.

Laminar airflow ventilation systems in orthopaedic operating room do not prevent surgical site infections: a systematic review and meta-analysis

BACKGROUND

Laminar airflow (LAF) technologies minimize infectious microorganisms to enhance air quality and surgical site infections (SSIs). LAF lowers SSIs in some clinical studies but not others. This study analyzes laminar airflow ventilation's capacity to reduce orthopaedic surgery-related SSIs.

METHODS

The PRISMA-compliant keywords were utilized to conduct a search for pertinent articles in various databases including PubMed, MEDLINE, CENTRAL, Web of Sciences, and the Cochrane databases. Observational studies, including retrospective, prospective, and cohort designs, satisfy the PICOS criteria for research methodology. The assessment of quality was conducted utilizing the Robvis software, while the meta-analysis was performed using the RevMan application. The study's results were assessed based on effect sizes of odds ratio (OR) and risk ratio (RR).

RESULTS

From 2000 to 2022, 10 randomized controlled clinical trials with 10,06,587 orthopaedic surgery patients met the inclusion criteria. The primary outcomes were: (1) Risk of SSI, (2) Bacterial count in sampled air and (3) Reduction in SSIs. The overall pooled OR of all included studies was 1.70 (95% CI 1.10-2.64), and the overall pooled RR was 1.27 (95% CI 1.02-1.59) with p < 0.05. LAF is ineffective at preventing SSIs in orthopaedic procedures due to its high-risk ratio and odds ratio.

CONCLUSIONS

The present meta-analysis has determined that the implementation of LAF systems does not result in a significant reduction in the incidence of surgical site infections (SSIs), bacterial count in the air, or SSIs occurrence in orthopaedic operating rooms. Consequently, the installation of said equipment in operating rooms has been found to be both expensive and inefficient.

The application value of operating room ventilation with laminar airflow for surgical site infection: A protocol for a systematic review and meta-analysis

BACKGROUND

The presence of biological particles in the air inside operating theatres has the potential to cause severe surgical site infections. Recently, laminar airflow systems have been regarded as a means to reducing surgical site infections using airborne microbes. Still, other publications have argued the benefits of laminar airflow systems, stating the likelihood of adverse effects. Therefore, we will conduct this systematic study to evaluate the applicational value of adopting laminar airflow systems in operating theatres to minimize surgical site infections.

METHODS

Reporting of this study adheres to the guidelines of Preferred Reporting Items for Systematic Review and Meta-analysis Protocols. The authors will perform a systematic search on MEDLINE, Web of Science, EMBASE, the China national knowledge infrastructure, and the Cochrane Library from their commencement until June 2021. The search will identify relevant randomized and non-randomized controlled trials that evaluates the applicational value of using laminar airflow ventilation in surgical theatres to minimize surgical site infections. There are no restrictions on language. Two authors will independently screen the identified studies, perform data extraction, and use an appropriate method to evaluate the bias risk in the included studies.

RESULTS

The work done in the present study will enhance the existing literature on the applicational value of laminar airflow ventilation in surgical theatre to reduce surgical site infections.

CONCLUSION

The outcomes are a reference for healthcare practitioners and patients when making informed decisions regarding care during surgeries.

The possible effect of different types of ventilation on reducing operation theatre infections: a meta-analysis

INTRODUCTION

The relation between type of ventilation used in the operating theatre and surgical site infection has drawn considerable attention. It has been reported that there is a possible relationship between the type of ventilation used in the operation theatre and surgical site infection. This meta-analysis was performed to evaluate this relationship.

METHODS

Through a systematic literature search up to May 2020, 14 studies describing 590,121 operations, 328,183 were performed under laminar airflow ventilation and 2,611,938 were performed under conventional ventilation. Studies were identified that reported relationships between type of ventilation with its different categories and surgical site infection (10 studies were related to surgical site infection in total hip replacement, 7 in total knee arthroplasties and 3 in different abdominal and open vascular surgery). Odds ratios with 95% confidence intervals were calculated comparing surgical site infection prevalence and type of theatre ventilation using the dichotomous method with a random or fixed-effect model.

FINDINGS

No significant difference was found between surgery performed under laminar airflow ventilation and conventional ventilation in total hip replacement (OR 1.23; 95% CI 0.97-1.56, p = 0.09), total knee arthroplasties (OR 1.14; 95% CI 0.62-2.09, p = 0.67) or different abdominal and open vascular surgery (OR 0.75; 95% CI 0.43-1.33, p = 0.33). The impact of the type of theatre ventilation may have no influence on surgical site infection as a tool for decreasing its occurrence.

CONCLUSIONS

Based on this meta-analysis, operating under laminar airflow or conventional ventilation may have no independent relationship with the risk of surgical site infection. This relationship forces us not to recommend the use of laminar airflow ventilation since it has a much higher cost compared with conventional ventilation.

The effect of type of ventilation used in the operating room and surgical site infection: A meta-analysis

BACKGROUND

The relation between type of ventilation used in the operating room and surgical site infection has drawn considerable attention with its conflicting results. A possible relationship between the type of ventilation used in the operating room and surgical site infection has been reported. This meta-analysis was performed to evaluate this relationship.

METHODS

A systematic literature search up to May 2020 identified 14 studies with 590,121 operations, 328,183 operations of which were performed under laminar airflow ventilation and 261,938 of which were performed operations under conventional ventilation. These articles reported relationships between type of operating-room ventilation with its different categories and surgical site infection: 10 studies were related to surgical site infection in the total hip replacement; 7 studies in total knee arthroplasties; and 3 studies in different abdominal and open vascular surgery. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated comparing surgical site infection prevalence and type of operating room ventilation using the dichotomous method with a random-effects or fixed-effects model.

RESULTS

No significant difference was found between operation performed under laminar airflow ventilation and conventional ventilation in total hip replacement (OR, 1.23; 95% CI, 0.97-1.56, P = .09), in total knee arthroplasties (OR, 1.14; 95% CI, 0.62-2.09; P = .67), and in different abdominal and open vascular surgery (OR, 0.75; 95% CI, 0.43-1.33; P = .33). The impact of the type of operating room ventilation may have no influence on surgical site infection as a tool for decreasing its occurrence.

CONCLUSIONS

Based on this meta-analysis, operating under laminar airflow or conventional ventilation may have no independent relationship with the risk of surgical site infection. This relationship forces us not to recommend the use of laminar airflow ventilation because it has a much higher cost compared to conventional ventilation.

Effects of forced air warming systems on the airflow and sanitation quality of operating rooms with non-laminar airflow systems

Background

: Previous studies have demonstrated that forced air warming (FAW) can be used safely in operating rooms with laminar airflow (LAF) ventilation systems. However, the effects of FAW on the airflow at surgical sites under non-LAF (nLAF) ventilation systems remain unclear, as nLAF systems generate outlet-to-inlet multidirectional airflows of the air conditioning system. Here, we evaluate the effects of FAW on the airflow and sanitation quality in surgical fields with nLAF ventilation systems.

Methods

: The airflow speed and direction were measured using a three-dimensional ultrasonic anemometer. Sanitation quality was evaluated by measuring the amount of dust particles after the activation of air conditioning.

Results

: FAW caused no meaningful airflow (> 10 cm/sec) and did not diminish the sanitation quality in the surgical field separated by the anesthesia screen. Above the head area, the upward FAW airflow was not counteracted by nLAF, which caused an upward airflow at the edges of the operating table, originating from outside of the operating table and the floor.

Conclusions

: Sanitation quality was kept under FAW working even in an nLAF-equipped OR. According to the inlet/outlet layouts of nLAF, the upward FAW-induced airflow in the head area was not counteracted, and the upward airflow from the floor induced by the air conditioner outlet could be detected.

Surgical site infection prevention measures in General Surgery: Position statement by the Surgical Infections Division of the Spanish Association of Surgery

Surgical site infection is associated with prolonged hospital stay and increased morbidity, mortality and healthcare costs, as well as a poorer patient quality of life. Many hospitals have adopted scientifically-validated guidelines for the prevention of surgical site infection. Most of these protocols have resulted in improved postoperative results. The Surgical Infection Division of the Spanish Association of Surgery conducted a critical review of the scientific evidence and the most recent international guidelines in order to select measures with the highest degree of evidence to be applied in Spanish surgical services. The best measures are: no removal or clipping of hair from the surgical field, skin decontamination with alcohol solutions, adequate systemic antibiotic prophylaxis (administration within 30-60minutes before the incision in a single preoperative dose; intraoperative re-dosing when indicated), maintenance of normothermia and perioperative maintenance of glucose levels.

Cutibacterium acnes Infection in Orthopedics: Microbiology, Clinical Findings, Diagnostic Strategies, and Management

Cutibacterium (formerly called Propionibacterium) acnes is a human skin flora often implicated in orthopedic infections. The unique characteristics of this microorganism make the diagnosis of infection difficult. The diagnosis often is made based on clinical evidence, radiographic signs, and laboratory and/or surgical findings combined. Treatment often involves both pharmacologic and surgical methods. In addition, formation of biofilms and increased resistance to drugs exhibited by the microorganism can require combined antimicrobial therapy. Prophylactic measures are particularly important, but no single method has been shown to fully eliminate the risk of C acnes infections. Previous reports have focused on C acnes infections involving surgical implants or after certain orthopedic procedures, particularly in the shoulder and spine. This article reviews current clinical, diagnostic, and treatment principles for C acnes in orthopedics in general. [Orthopedics. 2020; 43(1):52-61.].

Air quality in the operating room: Surgical site infections, HVAC systems and discipline - position paper of the German Society of Hospital Hygiene (DGKH)

In recent years, there has been an ongoing discussion about the value of laminar airflow (LAF=low turbulence displacement ventilation) in the operating room for prevention of surgical site infections (SSI). Some publications, e.g., from the WHO, issued the demand to no longer build LAF ceilings in operating rooms. The present statement deals critically with this position and justifies the use of LAF ceilings in different ways: Many of the papers cited by the WHO and others for the case against LAF do not provide reliable data.The remaining studies which might be used for answering the question give quite different results, also in favor of LAF.The size of the LAF ceiling in many studies is not given or mostly too small in comparison to actual technical requirements.LAF in different countries can mean quite different techniques (e.g., the US in comparison to Germany) so that the results of studies that do not take this into account may not be comparable.LAF has positive effects in terms of reducing particulate and bacterial load, associated with increased airflow in the surgical working area. A reduction of carcinogenic substances in the air may also be assumed, which would increase workers' safety. Thus, this paper recommends building LAF ceilings in the future as well, depending on the operations intended. Further, this paper gives an overview of possible reasons for surgical site infections and highlights the importance of discipline in the operating theatre.

Variation in timing and type of groin wound complications highlights the need for uniform reporting standards

BACKGROUND

Groin wound infections represent a substantial source of patients' morbidity and resource utilization. Definitions and reporting times of groin infections are poorly standardized, which limits our understanding of the true scope of the problem and potentially leads to event under-reporting. Our objective was to investigate the timing and variation of groin wound complications after vascular surgery.

METHODS

We reviewed all patients who underwent vascular surgery with a groin incision at our institution during 2013 (N = 256; 32% female; mean age, 68.8 years). We analyzed patient- and procedure-level variables. Our primary outcome was any groin complication within 180 days. We classified groin-related events as major (hospital readmission or reoperation for groin wound) or minor (wound opened in clinic, initiation of antibiotics specifically for a groin wound, or new groin hematoma or wound drainage).

RESULTS

The Kaplan-Meier estimated rate of groin complications at 180 days was 23% (n = 53/256); 29 (54%) were major and 24 (46%) were minor. The Kaplan-Meier 30-day event rate was 13% for any complication and only 3% for major complications, indicating that most events occurring within the first 30 days did not require readmission or reoperation. By 180 days, the overall complication rate rose to 23% and the major event rate to 14%, indicating that nearly all complications occurring after 30 days required readmission or reoperation. Those with a groin complication more commonly had tissue loss (23% vs 12%; P = .05), underwent infrainguinal bypass (42% vs 22%; P=.004), had a redo incision (32% vs 18%; P = .03), and had a longer operation (77% vs 65% surgery >200 minutes; P = .07). There were no significant differences in patients' comorbidities, skin closure, dressing type, prosthetic implants, hemostatic agents, or discharge status.

CONCLUSIONS

Whereas >20% of patients suffered a groin complication, nearly half of these events occurred after 30 days. Standardized reporting measures limited to 30-day events or infection definitions that are limited to the need for antibiotic use may misrepresent the true infection rate and thus highlight the need for uniform reporting standards.

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.

Effect of laminar airflow ventilation on surgical site infections: a systematic review and meta-analysis

BACKGROUND

The role of the operating room's ventilation system in the prevention of surgical site infections (SSIs) is widely discussed, and existing guidelines do not reflect current evidence. In this context, laminar airflow ventilation was compared with conventional ventilation to assess their effectiveness in reducing the risk of SSIs.

METHODS

We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and WHO regional medical databases from Jan 1, 1990, to Jan 31, 2014. We updated the search for MEDLINE for the period between Feb 1, 2014, and May 25, 2016. We included studies most relevant to our predefined question: is the use of laminar airflow in the operating room associated with the reduction of overall or deep SSI as outcomes in patients of any age undergoing surgical operations? We excluded studies not relevant to the study question, studies not in the selected languages, studies published before Jan 1, 1990, or after May 25, 2016, meeting or conference abstracts, and studies of which the full text was not available. Data were extracted by two independent investigators, with disagreements resolved through further discussion. Authors were contacted if the full-text article was not available, or if important data or information on the paper's content was absent. Studies were assessed for publication bias. Grading of recommendations assessment, development, and evaluation was used to assess the quality of the identified evidence. Meta-analyses were done with RevMan (version 5.3).

FINDINGS

We identified 1947 records of which 12 observational studies were comparing laminar airflow ventilation with conventional turbulent ventilation in orthopaedic, abdominal, and vascular surgery. The meta-analysis of eight cohort studies showed no difference in risk for deep SSIs following total hip arthroplasty (330 146 procedures, odds ratio [OR] 1·29, 95% CI 0·98-1·71; p=0·07, I²=83%). For total knee arthroplasty, the meta-analysis of six cohort studies showed no difference in risk for deep SSIs (134 368 procedures, OR 1·08, 95% CI 0·77-1·52; p=0·65, I²=71%). For abdominal and open vascular surgery, the meta-analysis of three cohort studies found no difference in risk for overall SSIs (63 472 procedures, OR 0·75, 95% CI 0·43-1·33; p=0·33, I²=95%).

INTERPRETATION

The available evidence shows no benefit for laminar airflow compared with conventional turbulent ventilation of the operating room in reducing the risk of SSIs in total hip and knee arthroplasties, and abdominal surgery. Decision makers, medical and administrative, should not regard laminar airflow as a preventive measure to reduce the risk of SSIs. Consequently, this equipment should not be installed in new operating rooms.

FUNDING

None.

A comparison of airborne bacterial fallout between orthopaedic and vascular surgery

INTRODUCTION The objective of the study was to compare bacterial fallout during vascular prosthesis insertion and orthopaedic major joint replacement performed in conventional and laminar flow ventilation, respectively. MATERIALS AND METHODS A prospective single-centre case control study of 21 consecutive elective vascular procedures involving prosthetic graft insertion and 24 consecutive elective orthopaedic major joint replacements were tested for degree of bacterial fallout using agar settle plates. Preparation time, waiting time and total procedure duration were collected at the time of surgery, and bacterial colony counts on the agar settle plates from airborne bacterial fallout were counted after an incubation period. RESULTS Bacterial fallout count in vascular prosthetic graft insertion was 15-fold greater than in orthopaedic prosthetic joint insertion (15, (IQR 15) vs 1, (IQR 3) respectively, P < 0.0001, Wilcoxon). Waiting time and patient transfer did not significantly increase bacterial fallout counts during the procedure (P = 0.9). CONCLUSIONS Vascular surgical theatres have significantly higher bacterial fallout compared with orthopaedic theatres. This may be partly explained by orthopaedic surgery being routinely performed in laminar flow ventilation, a practice which has not been widely adopted for vascular surgery, in which prosthetic infection may also result in significant mortality and morbidity.

New WHO recommendations on intraoperative and postoperative measures for surgical site infection prevention: an evidence-based global perspective

Surgical site infections (SSIs) are the most common health-care-associated infections in developing countries, but they also represent a substantial epidemiological burden in high-income countries. The prevention of these infections is complex and requires the integration of a range of preventive measures before, during, and after surgery. No international guidelines are available and inconsistencies in the interpretation of evidence and recommendations in national guidelines have been identified. Considering the prevention of SSIs as a priority for patient safety, WHO has developed evidence-based and expert consensus-based recommendations on the basis of an extensive list of preventive measures. We present in this Review 16 recommendations specific to the intraoperative and postoperative periods. The WHO recommendations were developed with a global perspective and they take into account the balance between benefits and harms, the evidence quality level, cost and resource use implications, and patient values and preferences.

Transmission of Mycobacterium chimaera from Heater-Cooler Units during Cardiac Surgery despite an Ultraclean Air Ventilation System

All such units should be separated from air that can gain access to sterile areas.

Heater–cooler units (HCUs) were recently identified as a source of Mycobacterium chimaera causing surgical site infections. We investigated transmission of this bacterium from HCUs to the surgical field by using a thermic anemometer and particle counter, videotape of an operating room equipped with an ultraclean laminar airflow ventilation system, and bacterial culture sedimentation plates in a nonventilated room. Smoke from the HCU reached the surgical field in 23 s by merging with ultraclean air. The HCU produced on average 5.2, 139, and 14.8 particles/min in the surgical field at positions Off, On/oriented toward, and On/oriented away, respectively. Culture plates were positive for M. chimaera<5 m from the HCU in the test room. These experiments confirm airborne transmission of M. chimaera aerosols from a contaminated HCU to an open surgical field despite ultraclean air ventilation. Efforts to mitigate infectious risks during surgery should consider contamination from water sources and airflow-generating devices.

Using a novel laminar flow unit provided effective total body hypothermia for neonatal hypoxic encephalopathy

AIM

This was a clinical observational trial on a laminar flow device that provides total body hypothermia for infants with hypoxic ischaemic encephalopathy (HIE).

METHODS

We enrolled infants born at up to 35 weeks of gestation, who presented with HIE within six hours of birth. Total body cooling was achieved using the neonatal laminar flow unit for 72 hours, with continuous rectal temperature servo control, isolation and humidification. Outcome measures were cerebral palsy, a Bayley II Mental Development Index score <70, hearing loss or blindness. We compared findings with previously published studies.

RESULTS

We included 26 newborn infants (69% male) with a birthweight of 3.341 ± 1658 g and gestational age of 38.2 ± 3.2 weeks. The majority (62.6%) had a Sarnat HIE score of three and 38.4% had a score of two. Total body cooling (33-34°C) was achieved in 70 minutes and maintained with servo control, showing very little variability until rewarming. At 18-24 months of age, two of the 18 survivors were diagnosed with cerebral palsy and one was diagnosed with impaired hearing.

CONCLUSION

The laminar flow unit proved effective in maintaining moderate total body hypothermia under well-controlled conditions, and our results were very similar to other studies.

The appropriate use of neurostimulation of the spinal cord and peripheral nervous system for the treatment of chronic pain and ischemic diseases: the Neuromodulation Appropriateness Consensus Committee

INTRODUCTION

The Neuromodulation Appropriateness Consensus Committee (NACC) of the International Neuromodulation Society (INS) evaluated evidence regarding the safety and efficacy of neurostimulation to treat chronic pain, chronic critical limb ischemia, and refractory angina and recommended appropriate clinical applications.

METHODS

The NACC used literature reviews, expert opinion, clinical experience, and individual research. Authors consulted the Practice Parameters for the Use of Spinal Cord Stimulation in the Treatment of Neuropathic Pain (2006), systematic reviews (1984 to 2013), and prospective and randomized controlled trials (2005 to 2013) identified through PubMed, EMBASE, and Google Scholar.

RESULTS

Neurostimulation is relatively safe because of its minimally invasive and reversible characteristics. Comparison with medical management is difficult, as patients considered for neurostimulation have failed conservative management. Unlike alternative therapies, neurostimulation is not associated with medication-related side effects and has enduring effect. Device-related complications are not uncommon; however, the incidence is becoming less frequent as technology progresses and surgical skills improve. Randomized controlled studies support the efficacy of spinal cord stimulation in treating failed back surgery syndrome and complex regional pain syndrome. Similar studies of neurostimulation for peripheral neuropathic pain, postamputation pain, postherpetic neuralgia, and other causes of nerve injury are needed. International guidelines recommend spinal cord stimulation to treat refractory angina; other indications, such as congestive heart failure, are being investigated.

CONCLUSIONS

Appropriate neurostimulation is safe and effective in some chronic pain conditions. Technological refinements and clinical evidence will continue to expand its use. The NACC seeks to facilitate the efficacy and safety of neurostimulation.

The effect of strict infection control policies on the rate of infection after elective foot and ankle surgery

The rate of surgical site infection after elective foot and ankle surgery is higher than that after other elective orthopaedic procedures.

Since December 2005, we have prospectively collected data on the rate of post-operative infection for 1737 patients who have undergone elective foot and ankle surgery. In March 2008, additional infection control policies, focused on surgical and environmental risk factors, were introduced in our department.

We saw a 50% reduction in the rate of surgical site infection after the introduction of these measures. We are, however, aware that the observed decrease may not be entirely attributable to these measures alone given the number of factors that predispose to post-operative wound infection.

Cite this article: Bone Joint J 2015;97-B:516–19.

Laminar airflow and the prevention of surgical site infection. More harm than good?

INTRODUCTION

Laminar airflow (LAF) systems are thought to minimise contamination of the surgical field with airborne microbes and thus to contribute to reducing surgical site infections (SSI). However recent publications have questioned whether LAF ventilation confers any significant benefit and may indeed be harmful.

METHODS

A detailed literature review was undertaken through www.Pubmed.com and Google scholar (http://scholar.google.com). Search terms used included "laminar flow". "laminar airflow", "surgical site infection prevention", "theatre ventilation" and "operating room ventilation", "orthopaedic theatre" and "ultra-clean ventilation". Peer-reviewed publications in the English language over the last 50 years were included, up to and including March 2014.

RESULTS

Laminar airflow systems are predominantly used in clean prosthetic implant surgery. Several studies have demonstrated decreased air bacterial contamination with LAF using bacterial sedimentation plates placed in key areas of the operating room. However, apart from the initial Medical Research Council study, there are few clinical studies demonstrating a convincing correlation between decreased SSI rates and LAF. Moreover, recent analyses suggest increased post-operative SSI rates.

CONCLUSION

It is premature to dispense with LAF as a measure to improve air quality in operating rooms where prosthetic joint surgery is being carried out. However, new multi-centre trials to assess this or the use of national prospective surveillance systems to explore other variables that might explain these findings such as poor operating room discipline are needed, to resolve this important surgical issue.

A laminar flow unit for the care of critically ill newborn infants

INTRODUCTION

Medical and nursing care of newborns is predicated on the delicate control and balance of several vital parameters. Closed incubators and open radiant warmers are the most widely used devices for the care of neonates in intensive care; however, several well-known limitations of these devises have not been resolved. The use of laminar flow is widely used in many fields of medicine, and may have applications in neonatal care.

OBJECTIVE

To describe the neonatal laminar flow unit, a new equipment we designed for care of ill newborns.

METHODS

The idea, design, and development of this device was completed in Sao Paulo, Brazil. The unit is an open mobile bed designed with the objective of maintaining the advantages of the incubator and radiant warmer, while overcoming some of their inherent shortcomings; these shortcomings include noise, magnetic fields and acrylic barriers in incubators, and lack of isolation and water loss through skin in radiant warmers. The unit has a pump that aspirates environmental air which is warmed by electrical resistance and decontaminated with High Efficiency Particulate Air Filter (HEPA) filters (laminar flow). The flow is directed by an air flow directioner. The unit has an embedded humidifier to increase humidity in the infant's microenvironment and a servo control mechanism for regulation of skin temperature.

RESULTS

The laminar flow unit is open and facilitates access of care providers and family, which is not the case in incubators. It provides warming by convection at an air velocity of 0.45 m/s, much faster than an incubator (0.1 m/s). The system provides isolation 1000 class (less than 1,000 particles higher than 0.3 micron per cubic feet at all times). This is much more protection than an incubator provides and more than radiant warmers, which have no isolation whatsoever. Additionally, it provides humidification of the newborn's microenvironment (about 60% relative humidity), which is impossible with a radiant warmer, which produces high water body loss. It has no mechanical barriers like acrylic walls, its magnetic field is lower than an incubator (0.25 μt versus 1.2 μt), and the noise is minimal compared to incubators. The unit is also able to provide controlled total body hypothermia, which is not possible with either of the other two units.

CONCLUSION

The laminar flow unit for neonatal care is a novel device which we recently developed. The introduction of laminar flow technology represents a real innovation in the neonatal field. We have described the various components of the unit and the potential advantages for management of ill neonates. This will hopefully lead to improved clinical outcomes and more effective neonatal management and safety.