The incidence of potentially serious complications during non-obstetric anaesthetic practice in the United Kingdom: an analysis from the 7th National Audit Project (NAP7) activity survey

Complications and critical incidents arising during anaesthesia due to patient, surgical or anaesthetic factors, may cause harm themselves or progress to more severe events, including cardiac arrest or death. As part of the 7th National Audit Project of the Royal College of Anaesthetists, we studied a prospective national cohort of unselected patients. Anaesthetists recorded anonymous details of all cases undertaken over 4 days at their site through an online survey. Of 416 hospital sites invited to participate, 352 (85%) completed the survey. Among 24,172 cases, 1922 discrete potentially serious complications were reported during 1337 (6%) cases. Obstetric cases had a high reported major haemorrhage rate and were excluded from further analysis. Of 20,996 non-obstetric cases, 1705 complications were reported during 1150 (5%) cases. Circulatory events accounted for most complications (616, 36%), followed by airway (418, 25%), metabolic (264, 15%), breathing (259, 15%), and neurological (41, 2%) events. A single complication was reported in 851 (4%) cases, two complications in 166 (1%) cases and three or more complications in 133 (1%) cases. In non-obstetric elective surgery, all complications were 'uncommon' (10-100 per 10,000 cases). Emergency (urgent and immediate priority) surgery accounted for 3454 (16%) of non-obstetric cases but 714 (42%) of complications with severe hypotension, major haemorrhage, severe arrhythmias, septic shock, significant acidosis and electrolyte disturbances all being 'common' (100-1000 per 10,000 cases). Based on univariate analysis, complications were associated with: younger age; higher ASA physical status; male sex; increased frailty; urgency and extent of surgery; day of the week; and time of day. These data represent the rates of potentially serious complications during routine anaesthesia care and may be valuable for risk assessment and patient consent.

Peri-operative cardiac arrest: epidemiology and clinical features of patients analysed in the 7th National Audit Project of the Royal College of Anaesthetists

The 7th National Audit Project of the Royal College of Anaesthetists studied peri-operative cardiac arrest in the UK, a topic of importance to patients, anaesthetists and surgeons. Here we report the results of the 12-month registry, from 16 June 2021 to 15 June 2022, focusing on epidemiology and clinical features. We reviewed 881 cases of peri-operative cardiac arrest, giving an incidence of 3 in 10,000 anaesthetics (95%CI 3.0-3.5 per 10,000). Incidence varied with patient and surgical factors. Compared with denominator survey activity, patients with cardiac arrest: included more males (56% vs. 42%); were older (median (IQR) age 60.5 (40.5-80.5) vs. 50.5 (30.5-70.5) y), although the age distribution was bimodal, with infants and patients aged > 66 y overrepresented; and were notably more comorbid (73% ASA physical status 3-5 vs. 27% ASA physical status 1-2). The surgical case-mix included more weekend (14% vs. 11%), out-of-hours (19% vs. 10%), non-elective (65% vs. 30%) and major/complex cases (60% vs. 28%). Cardiac arrest was most prevalent in orthopaedic trauma (12%), lower gastrointestinal surgery (10%), cardiac surgery (9%), vascular surgery (8%) and interventional cardiology (6%). Specialities with the highest proportion of cases relative to denominator activity were: cardiac surgery (9% vs. 1%); cardiology (8% vs. 1%); and vascular surgery (8% vs. 2%). The most common causes of cardiac arrest were: major haemorrhage (17%); bradyarrhythmia (9%); and cardiac ischaemia (7%). Patient factors were judged a key cause of cardiac arrest in 82% of cases, anaesthesia in 40% and surgery in 35%.

Peri-operative cardiac arrest: management and outcomes of patients analysed in the 7th National Audit Project of the Royal College of Anaesthetists

The 7th National Audit Project of the Royal College of Anaesthetists studied peri-operative cardiac arrest in the UK, a topic of importance to patients, anaesthetists and surgeons. We report the results of the 12-month registry phase, from 16 June 2021 to 15 June 2022, focusing on management and outcomes. Among 881 cases of peri-operative cardiac arrest, the initial rhythm was non-shockable in 723 (82%) cases, most commonly pulseless electrical activity. There were 665 (75%) patients who survived the initial event and 384 (52%) who survived to hospital discharge. A favourable functional outcome (based on modified Rankin Scale score) was reported for 249 (88%) survivors. Outcomes varied according to arrest rhythm. The highest rates of survival were seen for bradycardic cardiac arrests with 111 (86%) patients surviving the initial event and 77 (60%) patients surviving the hospital episode. The lowest survival rates were seen for patients with pulseless electrical activity, with 312 (68%) surviving the initial episode and 156 (34%) surviving to hospital discharge. Survival to hospital discharge was worse in patients at the extremes of age with 76 (40%) patients aged > 75 y and 9 (45%) neonates surviving. Hospital survival was also associated with surgical priority, with 175 (88%) elective patients and 176 (37%) non-elective patients surviving to discharge. Outcomes varied with the cause of cardiac arrest, with lower initial survival rates for pulmonary embolism (5, 31%) and bone cement implantation syndrome (9, 45%), and hospital survival of < 25% for pulmonary embolism (0), septic shock (13, 24%) and significant hyperkalaemia (1, 20%). Overall care was rated good in 464 (53%) cases, and 18 (2%) cases had overall care rated as poor. Poor care elements were present in a further 245 (28%) cases. Care before cardiac arrest was the phase most frequently rated as poor (92, 11%) with elements of poor care identified in another 186 (21%) cases. These results describe the management and outcomes of peri-operative cardiac arrest in UK practice for the first time.

Organisation of UK hospitals and anaesthetic departments in the treatment of peri-operative cardiac arrest: an analysis from the 7th National Audit Project (NAP7) local co-ordinator baseline survey

We report the results of the Royal College of Anaesthetists' 7th National Audit Project organisational baseline survey sent to every NHS anaesthetic department in the UK to assess preparedness for treating peri-operative cardiac arrest. We received 199 responses from 277 UK anaesthetic departments, representing a 72% response rate. Adult and paediatric anaesthetic care was provided by 188 (95%) and 165 (84%) hospitals, respectively. There was no paediatric intensive care unit on-site in 144 (87%) hospitals caring for children, meaning transfer of critically ill children is required. Remote site anaesthesia is provided in 182 (92%) departments. There was a departmental resuscitation lead in 113 (58%) departments, wellbeing lead in 106 (54%) and departmental staff wellbeing policy in 81 (42%). A defibrillator was present in every operating theatre suite and in all paediatric anaesthesia locations in 193 (99%) and 149 (97%) departments, respectively. Advanced airway equipment was not available in: every theatre suite in 13 (7%) departments; all remote locations in 103 (57%) departments; and all paediatric anaesthesia locations in 23 (15%) departments. Anaesthetic rooms were the default location for induction of anaesthesia in adults and children in 148 (79%) and 121 (79%) departments, respectively. Annual updates in chest compressions and in defibrillation were available in 149 (76%) and 130 (67%) departments, respectively. Following a peri-operative cardiac arrest, debriefing and peer support programmes were available in 154 (79%) and 57 (29%) departments, respectively. While it is likely many UK hospitals are very well prepared to treat anaesthetic emergencies including cardiac arrest, the survey suggests this is not universal.

The 7th National Audit Project (NAP7) baseline survey of individual anaesthetists: preparedness for and experiences of peri-operative cardiac arrest

The Royal College of Anaesthetists' 7th National Audit Project baseline survey assessed knowledge, attitudes, practices and experiences of peri-operative cardiac arrests among UK anaesthetists and Anaesthesia Associates. We received 10,746 responses, representing a 71% response rate. In-date training in adult and paediatric advanced life support was reported by 9646 (90%) and 7125 (66%) anaesthetists, respectively. There were 8994 (84%) respondents who were confident in leading a peri-operative cardiac arrest, with males more confident than females, but only 5985 (56%) were confident in leading a debrief and 7340 (68%) communicating with next of kin. In the previous two years, 4806 (46%) respondents had managed at least one peri-operative cardiac arrest, of which 321 (7%) and 189 (4%) of these events involved a child or an obstetric patient, respectively. Respondents estimated the most common causes of peri-operative cardiac arrest to be hypovolaemia, hypoxaemia and cardiac ischaemia, with haemorrhage coming fifth. However, the most common reported causes for the most recently attended peri-operative cardiac arrest were haemorrhage; (927, 20%); anaphylaxis (474, 10%); and cardiac ischaemia (397, 9%). Operating lists or shifts were paused or stopped after 1330 (39%) cardiac arrests and 1693 (38%) respondents attended a debrief, with 'hot' debriefs most common. Informal wellbeing support was relatively common (2458, 56%) and formal support was uncommon (472, 11%). An impact on future care delivery was reported by 196 (4%) anaesthetists, most commonly a negative psychological impact. Management of a peri-operative cardiac arrest during their career was reported by 8654 (85%) respondents. The overall impact on professional life was more often judged positive (2630, 30%) than negative (1961, 23%), but impact on personal life was more often negative.

Patient characteristics, anaesthetic workload and techniques in the UK: an analysis from the 7th National Audit Project (NAP7) activity survey

Detailed contemporary knowledge of the characteristics of the surgical population, national anaesthetic workload, anaesthetic techniques and behaviours are essential to monitor productivity, inform policy and direct research themes. Every 3-4 years, the Royal College of Anaesthetists, as part of its National Audit Projects (NAP), performs a snapshot activity survey in all UK hospitals delivering anaesthesia, collecting patient-level encounter data from all cases under the care of an anaesthetist. During November 2021, as part of NAP7, anaesthetists recorded details of all cases undertaken over 4 days at their site through an online survey capturing anonymous patient characteristics and anaesthetic details. Of 416 hospital sites invited to participate, 352 (85%) completed the activity survey. From these, 24,177 reports were returned, of which 24,172 (99%) were included in the final dataset. The work patterns by day of the week, time of day and surgical specialty were similar to previous NAP activity surveys. However, in non-obstetric patients, between NAP5 (2013) and NAP7 (2021) activity surveys, the estimated median age of patients increased by 2.3 years from median (IQR) of 50.5 (28.4-69.1) to 52.8 (32.1-69.2) years. The median (IQR) BMI increased from 24.9 (21.5-29.5) to 26.7 (22.3-31.7) kg.m^-2 . The proportion of patients who scored as ASA physical status 1 decreased from 37% in NAP5 to 24% in NAP7. The use of total intravenous anaesthesia increased from 8% of general anaesthesia cases to 26% between NAP5 and NAP7. Some changes may reflect the impact of the COVID-19 pandemic on the anaesthetic population, though patients with confirmed COVID-19 accounted for only 149 (1%) cases. These data show a rising burden of age, obesity and comorbidity in patients requiring anaesthesia care, likely to impact UK peri-operative services significantly.

Identification of the Language Network from Resting-State fMRI in Patients with Brain Tumors: How Accurate Are Experts?

BACKGROUND AND PURPOSE

Resting-state fMRI helps identify neural networks in presurgical patients who may be limited in their ability to undergo task-fMRI. The purpose of this study was to determine the accuracy of identifying the language network from resting-state-fMRI independent component analysis (ICA) maps.

MATERIALS AND METHODS

Through retrospective analysis, patients who underwent both resting-state-fMRI and task-fMRI were compared by identifying the language network from the resting-state-fMRI data by 3 reviewers. Blinded to task-fMRI maps, these investigators independently reviewed resting-state-fMRI ICA maps to potentially identify the language network. Reviewers ranked up to 3 top choices for the candidate resting-state-fMRI language map. We evaluated associations between the probability of correct identification of the language network and some potential factors.

RESULTS

Patients included 29 men and 14 women with a mean age of 41 years. Reviewer 1 (with 17 years' experience) demonstrated the highest overall accuracy with 72%; reviewers 2 and 3 (with 2 and 7 years' experience, respectively) had a similar percentage of correct responses (50% and 55%). The highest accuracy used ICA50 and the top 3 choices (81%, 65%, and 60% for reviewers 1, 2, and 3, respectively). The lowest accuracy used ICA50, limiting each reviewer to the top choice (58%, 35%, and 42%).

CONCLUSIONS

We demonstrate variability in the accuracy of blinded identification of resting-state-fMRI language networks across reviewers with different years of experience.

Major haemorrhage: past, present and future

Major haemorrhage is a leading cause of morbidity and mortality worldwide. Successful treatment requires early recognition, planned responses, readily available resources (such as blood products) and rapid access to surgery or interventional radiology. Major haemorrhage is often accompanied by volume loss, haemodilution, acidaemia, hypothermia and coagulopathy (factor consumption and fibrinolysis). Management of major haemorrhage over the past decade has evolved to now deliver a 'package' of haemostatic resuscitation including: surgical or radiological control of bleeding; regular monitoring of haemostasis; advanced critical care support; and avoidance of the lethal triad of hypothermia, acidaemia and coagulopathy. Recent trial data advocate for a more personalised approach depending on the clinical scenario. Fresh frozen plasma should be given as early as possible in major trauma in a 1:1 ratio with red blood cells until the results of coagulation tests are available. Tranexamic acid is a cheap, life-saving drug and is advocated in major trauma, postpartum haemorrhage and surgery, but not in patients with gastrointestinal bleeding. Fibrinogen levels should be maintained > 2 g.l^-1 in postpartum haemorrhage and > 1.5 g.l^-1 in other haemorrhage. Improving outcomes after major traumatic haemorrhage is now driving research to include extending blood-product resuscitation into prehospital care.

Methods of the 7th National Audit Project (NAP7) of the Royal College of Anaesthetists: peri-operative cardiac arrest

Cardiac arrest in the peri-operative period is rare but associated with significant morbidity and mortality. Current reporting systems do not capture many such events, so there is an incomplete understanding of incidence and outcomes. As peri-operative cardiac arrest is rare, many hospitals may only see a small number of cases over long periods, and anaesthetists may not be involved in such cases for years. Therefore, a large-scale prospective cohort is needed to gain a deep understanding of events leading up to cardiac arrest, management of the arrest itself and patient outcomes. Consequently, the Royal College of Anaesthetists chose peri-operative cardiac arrest as the 7th National Audit Project topic. The study was open to all UK hospitals offering anaesthetic services and had a three-part design. First, baseline surveys of all anaesthetic departments and anaesthetists in the UK, examining respondents' prior peri-operative cardiac arrest experience, resuscitation training and local departmental preparedness. Second, an activity survey to record anonymised details of all anaesthetic activity in each site over 4 days, enabling national estimates of annual anaesthetic activity, complexity and complication rates. Third, a case registry of all instances of peri-operative cardiac arrest in the UK, reported confidentially and anonymously, over 1 year starting 16 June 2021, followed by expert review using a structured process to minimise bias. The definition of peri-operative cardiac arrest was the delivery of five or more chest compressions and/or defibrillation in a patient having a procedure under the care of an anaesthetist. The peri-operative period began with the World Health Organization 'sign-in' checklist or first hands-on contact with the patient and ended either 24 h after the patient handover (e.g. to the recovery room or intensive care unit) or at discharge if this occured earlier than 24 h. These components described the epidemiology of peri-operative cardiac arrest in the UK and provide a basis for developing guidelines and interventional studies.

Downregulation of thrombomodulin-thrombin-activated protein C pathway as a mechanism for SARS-CoV-2 induced endotheliopathy and microvascular thrombosis

There is emerging evidence of microvascular thrombosis and thrombotic microangiopathy (TMA) induced by COVID-19, presumably from endothelial injury. Thrombomodulin (TM) is an endothelial glycoprotein that plays a dual role in maintaining healthy endothelium-as a natural anticoagulant by binding thrombin to activate protein C (APC) and a negative regulator of the alternate complement pathway (AP). TM is shed into the plasma as soluble TM (sTM) during endothelial injury. We hypothesize that SARS-CoV-2 spike proteins cause direct microvascular endothelial injury, leading to TM shedding, decreased activation of PC, and consequently, microvascular thrombosis in COVID-19. We conducted this study twofold: 1) in vivo, we assessed endothelial injury (by measuring sTM) and AP activation by quantifying Ba (cleavage product of AP component Factor B) in a cohort of critically ill COVID-19 pediatric patients and the implications on clinical outcomes; and 2)in vitro, we investigated endothelial injury (TM shedding) by SARS-COV-2 spike proteins and the subsequent functional consequence in activated PC (APC) levels and Ba levels. sTM and Ba in plasma samples from SARS-CoV-2 positive patients admitted to Texas Children's Hospital Pediatric Intensive Care Unit (n = 33) and from healthy controls (n = 38) were measured by ELISA. In vitro, confluent glomerular microvascular endothelial cells (GMVECs) were incubated for 48 h in the presence or absence (control) of purified SARS-CoV-2 spike proteins, S1 and S2. TM from the cell lysates while Ba and APC from the cell supernatants were measured by ELISA. sTM and Ba levels were significantly higher in the COVID-19 pediatric patients compared to healthy controls (p < 0.01 and p < 0.001, respectively). Among the COVID-19 patients, elevated sTM was associated with increased vasopressor use (p = 0.01) and elevated Ba was associated with increased duration of mechanical ventilation (p = 0.04). In vitro, surface bound TM and soluble APC were significantly lower in GMVECs after addition of spike proteins (p < 0.05), while Ba was undetectable in both control and spike proteins exposed GMVECs. In conclusion, we provide evidence of endothelial injury in COVID-19 pediatric patients and demonstrate a potential pathway of SARS-CoV-2 induced thrombosis. Decreased surface-bound TM results in lower amount of thrombin-TM complex, hence lesser activation of PC, likely leading to a pro-thrombotic state. These findings in GMVECs could explain the vulnerability of kidneys to COVID-19-induced TMA.

AB0516 IN-HOSPITAL MORTALITY IN YOUNG PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) AND ASSOCIATED CLINICAL FEATURES

Background

Patients with systemic lupus erythematosus (SLE) are three times more likely to die from any cause as compared to patients without SLE.1 This is largely driven by cardiovascular disease, malignancy, and an increased risk of infection. Alarmingly, recent studies have shown that younger patients with SLE are particularly vulnerable to all-cause mortality.1 However, there is a paucity in knowledge about patient characteristics and specific etiologies of mortality in this population that needs to be described in order to implement strategies to improve outcomes in younger patients with SLE.

Objectives

To identify disease characteristics and etiologies of mortality in young patients with SLE that died while hospitalized.

Methods

A retrospective chart review of a multi-institutional publicly funded health system in Texas, USA was performed. Deceased patients aged 18-49 with a 2019 EULAR/ACR diagnosis of SLE were identified from 2012 to 2021. Patients with mixed connective tissue disease, missing records, or cardiac arrest in the emergency room that did not have a clear etiology of death were excluded. Data was extracted from the electronic medical records by two independent reviewers to determine the most likely cause of death. If there was any discrepancy between the reviewers, this would be resolved by a third-party reviewer. Baseline demographics, disease activity by the SLE disease activity index (SLEDAI), medications, and reasons for prednisone administration were collected.

Results

Twenty- six patients with SLE (age range 22 to 48) that died in the hospital were identified. The most common cause of death was infection (58%) followed by lupus activity (15%). Of those that died of infection, all but one was on a two-month average dose of prednisone ≥10mg. Furthermore, the majority of patients (71%) that were on prednisone doses of ≥10mg had not undergone a prednisone taper within two months (i.e. were on a consistent dose). This was because of either persistent disease activity or poor follow-up.

Conclusion

To our knowledge, this is the first study to describe characteristics of young patients with SLE that died during hospitalization. Our findings show that young patients with SLE primarily die from infection while on increased doses of corticosteroids that have not been tapered. Further research is warranted to determine association and causality of these findings with mortality. Practitioners should remain vigilant and continue to taper steroids as able as this may be a potential source of mortality in young patients with SLE.

References

[1]Tselios K, Gladman DD, Sheane BJ, Su J, Urowitz M. All-cause, cause-specific and age-specific standardised mortality ratios of patients with systemic lupus erythematosus in Ontario, Canada over 43 years (1971-2013). Ann Rheum Dis 2019;78:802-6.

Table 1.

Baseline characteristics of SLE patients that experienced in-hospital mortality.

SLE Cases(n = 26)Female, n (%)20 (77)Age, range in years22 to 48Race and Ethnicity, n (%)Black6 (23)Hispanic19 (73)Asian1 (4)Disease manifestationsLupus nephritis18 (69)End-stage renal disease3 (12)SLEDAI before admission (median, IQR)7 (4 to 11)SLEDAI on admission (median, IQR)6 (2 to 11)MedicationsPrednisone25 (96)Hydroxychloroquine19 (73)Mycophenolate9 (35)Cyclophosphamide7 (27)Belimumab1 (4)Cause of deathInfection15 (58)Lupus activity4 (15)Cardiogenic shock2 (8)Cancer2 (8)Other3 (12)

IQR = Interquartile range

Acknowledgements

I have no acknowledgements to declare.

Disclosure of Interests

None declared

AB0488 THE UTILITY OF ERYTHROCYTE SEDIMENTATION RATE, C-REACTIVE PROTEIN, AND PROCALCITONIN IN DETECTING INFECTIONS IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS: A DIAGNOSTIC TEST ACCURACY REVIEW

Background

Patients with systemic lupus erythematosus (SLE) are at an increased risk of hospitalization for flares or infections. In practice, diagnosing SLE flares versus infection can be challenging as both present with similar signs and symptoms. Strategies are needed to help differentiate between infections and SLE flares in hospitalized patients. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and procalcitonin (PCT) are commonly used to aid in the diagnosis of infection in hospitalized patients, however, their utility in SLE is unclear.

Objectives

To summarize the evidence about accuracy of ESR, CRP, and PCT in diagnosing infection in hospitalized patients with SLE.

Methods

We searched five databases until April 2021. We included studies published in English investigating levels of ESR, CRP, or PCT on adults hospitalized with a diagnosis of SLE comparing infection versus non-infection. We excluded studies with no clinical data, inadequate data to perform analysis, different conditions, and not relevant study types (such as case reports, other reviews). We also excluded studies with overlapping data (e.g., abstracts that are later published as full-text articles). We used the Quality Assessment of Diagnostic Studies to assess for bias and applicability. We obtained pooled sensitivities and specificities from studies that used similar cut-offs. We also generated mean differences for ESR, CRP, and PCT in infection versus non-infection hospitalized SLE patients.

Results

We included 26 studies in our analysis. Most studies had an unclear or high risk of bias. Most patients from both infection and non-infection groups were women aged from 27-40 years. The definitions for infection were heterogenous but mainly included positive culture or biochemical testing, suggestive imaging, response to antibiotics, or obvious signs/symptoms (such as purulence). The CRP had a pooled sensitivity of 0.75 (95%CI 0.57-0.94) and specificity of 0.72 (0.59-0.85), PCT had a pooled sensitivity of 0.68 (95% CI 0.0.59-0.77) and specificity of 0.75 (0.59-0.90), and for ESR pooled estimates were not calculated due to insufficient data but sensitivity ranged from 50 to 69.8 and specificity from 38.5 to 55.6. Modifying cut-offs improved sensitivities and specificities (see Table 1). The ESR, CRP, and PCT mean differences were all greater in infection groups versus non-infection (10.1, 95% CI 3.2-17.0; 46.8, 95% CI 36.5-57.0; 0.53, 95% CI 0.26-0.80; respectively).

Table 1.

Pooled sensitivity and specificities of CRP and PCT

Studies(n)Sensitivity(95% CI)Specificity(95% CI)CRPCRP < 1030.68 (0.48-0.89)0.70 (0.62-0.77)CRP > 1020.91 (0.86-0.97)0.87 (0.81-0.93)Overall50.75 (0.57-0.94)0.72 (0.59-0.85)ProcalcitoninPCT > 0.230.66 (0.50-0.81)0.84 (0.76-0.92)PCT < 0.230.70 (0.61-0.80)0.61 (0.53-0.69)Overall60.68 (0.59-0.77)0.75 (0.59-0.90)

Conclusion

Our study showed that although ESR, CRP, and PCT mean values are increased in hospitalized infected SLE patients compared to patients with no infection, the included studies used varying cut-offs for sensitivities and specificities and definitions for infection decreasing the uncertainty on the results and making the clinical usefulness of these biomarkers unclear. Our findings at this time do not support the widespread use of these biochemical markers in SLE patients and highlight the need that more research is needed to investigate the use of these markers in this patient population.

Disclosure of Interests

None declared

Gap Statistics for Confined Particles with Power-Law Interactions

We consider the N particle classical Riesz gas confined in a one-dimensional external harmonic potential with power-law interaction of the form 1/r^{k}, where r is the separation between particles. As special limits it contains several systems such as Dyson's log-gas (k→0^{+}), the Calogero-Moser model (k=2), the 1D one-component plasma (k=-1), and the hard-rod gas (k→∞). Despite its growing importance, only large-N field theory and average density profile are known for general k. In this Letter, we study the fluctuations in the system by looking at the statistics of the gap between successive particles. This quantity is analogous to the well-known level-spacing statistics which is ubiquitous in several branches of physics. We show that the variance goes as N^{-b_{k}} and we find the k dependence of b_{k} via direct Monte Carlo simulations. We provide supporting arguments based on microscopic Hessian calculation and a quadratic field theory approach. We compute the gap distribution and study its system size scaling. Except in the range -1<k<0, we find scaling for all k>-2 with both Gaussian and non-Gaussian scaling forms.

Life-saving transfusion in autoimmune hemolytic anemia: a case report and procedure review of the dilution method

A woman with autoimmune hemolytic anemia (AIHA) presented in the emergency department with life-threatening anemia (hemoglobin 3 g/dL). Exaggeration of preexisting chronic anemia to severe anemia after a recent red blood cell (RBC) transfusion led to suspicion of delayed hemolytic transfusion reaction. Given the urgency for transfusion along with a stronger suspicion for coexistence of an alloantibody, the dilution method proposed by Lawrence Petz and George Garratty was used to find an RBC unit for transfusion. An alloantibody with Fy^b specificity was identified, which was masked by the coexistent autoantibody. This method is based on the assumption that the titers of an alloantibody are higher than that of autoantibody. Diluting the autoantibody would reveal the alloantibody and, for this purpose, a serial doubling dilution of serum is performed. This method has an important limitation of missing any alloantibodies with titers less than that of the autoantibody. In spite of this, this method may be of use at a resource-poor setting, where trained personnel and other reagents intended for advanced immunohematology methods are unavailable.