Corrigendum: Iatrogenic air embolism: pathoanatomy, thromboinflammation, endotheliopathy, and therapies

[This corrects the article DOI: 10.3389/fimmu.2023.1230049.].

Iatrogenic air embolism: pathoanatomy, thromboinflammation, endotheliopathy, and therapies

Iatrogenic vascular air embolism is a relatively infrequent event but is associated with significant morbidity and mortality. These emboli can arise in many clinical settings such as neurosurgery, cardiac surgery, and liver transplantation, but more recently, endoscopy, hemodialysis, thoracentesis, tissue biopsy, angiography, and central and peripheral venous access and removal have overtaken surgery and trauma as significant causes of vascular air embolism. The true incidence may be greater since many of these air emboli are asymptomatic and frequently go undiagnosed or unreported. Due to the rarity of vascular air embolism and because of the many manifestations, diagnoses can be difficult and require immediate therapeutic intervention. An iatrogenic air embolism can result in both venous and arterial emboli whose anatomic locations dictate the clinical course. Most clinically significant iatrogenic air emboli are caused by arterial obstruction of small vessels because the pulmonary gas exchange filters the more frequent, smaller volume bubbles that gain access to the venous circulation. However, there is a subset of patients with venous air emboli caused by larger volumes of air who present with more protean manifestations. There have been significant gains in the understanding of the interactions of fluid dynamics, hemostasis, and inflammation caused by air emboli due to in vitro and in vivo studies on flow dynamics of bubbles in small vessels. Intensive research regarding the thromboinflammatory changes at the level of the endothelium has been described recently. The obstruction of vessels by air emboli causes immediate pathoanatomic and immunologic and thromboinflammatory responses at the level of the endothelium. In this review, we describe those immunologic and thromboinflammatory responses at the level of the endothelium as well as evaluate traditional and novel forms of therapy for this rare and often unrecognized clinical condition.

Venous Air Embolism Activates Complement C3 Without Corresponding C5 Activation and Trigger Thromboinflammation in Pigs

Introduction

Air embolism may complicate invasive medical procedures. Bubbles trigger complement C3-mediated cytokine release, coagulation, and platelet activation in vitro in human whole blood. Since these findings have not been verified in vivo, we aimed to examine the effects of air embolism in pigs on thromboinflammation.

Methods

Forty-five landrace pigs, average 17 kg (range 8.5-30), underwent intravenous air infusion for 300 or 360 minutes (n=29) or served as sham (n=14). Fourteen pigs were excluded due to e.g. infections or persistent foramen ovale. Blood was analyzed for white blood cells (WBC), complement activation (C3a and terminal C5b-9 complement complex [TCC]), cytokines, and hemostatic parameters including thrombin-antithrombin (TAT) using immunoassays and rotational thromboelastometry (ROTEM). Lung tissue was analyzed for complement and cytokines using qPCR and immunoassays. Results are presented as medians with interquartile range.

Results

In 24 pigs receiving air infusion, WBC increased from 17×10⁹/L (10-24) to 28 (16-42) (p<0.001). C3a increased from 21 ng/mL (15-46) to 67 (39-84) (p<0.001), whereas TCC increased only modestly (p=0.02). TAT increased from 35 µg/mL (28-42) to 51 (38-89) (p=0.002). ROTEM changed during first 120 minutes: Clotting time decreased from 613 seconds (531-677) to 538 (399-620) (p=0.006), clot formation time decreased from 161 seconds (122-195) to 124 (83-162) (p=0.02) and α-angle increased from 62 degrees (57-68) to 68 (62-74) (p=0.02). In lungs from pigs receiving air compared to sham animals, C3a was 34 ng/mL (14-50) versus 4.1 (2.4-5.7) (p<0.001), whereas TCC was 0.3 CAU/mL (0.2-0.3) versus 0.2 (0.1-0.2) (p=0.02). Lung cytokines in pigs receiving air compared to sham animals were: IL-1β 302 pg/mL (190-437) versus 107 (66-120), IL-6 644 pg/mL (358-1094) versus 25 (23-30), IL-8 203 pg/mL (81-377) versus 21 (20-35), and TNF 113 pg/mL (96-147) versus 16 (13-22) (all p<0.001). Cytokine mRNA in lung tissue from pigs receiving air compared to sham animals increased 12-fold for IL-1β, 121-fold for IL-6, and 17-fold for IL-8 (all p<0.001).

Conclusion

Venous air embolism in pigs activated C3 without a corresponding C5 activation and triggered thromboinflammation, consistent with a C3-dependent mechanism. C3-inhibition might represent a therapeutic approach to attenuate this response.

Air Bubbles Activate Complement and Trigger Hemostasis and C3-Dependent Cytokine Release Ex Vivo in Human Whole Blood

Air bubbles trigger a C3-driven thromboinflammation in human whole blood.

Blocking C3, but not C5, attenuates the air-induced inflammation.

Avoiding ambient air in test tubes attenuates thromboinflammation.

Venous air embolism, which may complicate medical and surgical procedures, activates complement and triggers thromboinflammation. In lepirudin-anticoagulated human whole blood, we examined the effect of air bubbles on complement and its role in thromboinflammation. Whole blood from 16 donors was incubated with air bubbles without or with inhibitors of C3, C5, C5aR1, or CD14. Complement activation, hemostasis, and cytokine release were measured using ELISA and quantitative PCR. Compared with no air, incubating blood with air bubbles increased, on average, C3a 6.5-fold, C3bc 6-fold, C3bBbP 3.7-fold, C5a 4.6-fold, terminal complement complex sC5b9 3.6-fold, prothrombin fragments 1+2 (PTF1+2) 25-fold, tissue factor mRNA (TF-mRNA) 26-fold, microparticle tissue factor 6.1-fold, β-thromboglobulin 26-fold (all p < 0.05), and 25 cytokines 11-fold (range, 1.5–78-fold; all p < 0.0001). C3 inhibition attenuated complement and reduced PTF1+2 2-fold, TF-mRNA 5.4-fold, microparticle tissue factor 2-fold, and the 25 cytokines 2.7-fold (range, 1.4–4.9-fold; all p < 0.05). C5 inhibition reduced PTF1+2 2-fold and TF-mRNA 12-fold (all p < 0.05). C5 or CD14 inhibition alone reduced three cytokines, including IL-1β (p = 0.02 and p = 0.03). Combined C3 and CD14 inhibition reduced all cytokines 3.9-fold (range, 1.3–9.5-fold; p < 0.003) and was most pronounced for IL-1β (3.2- versus 6.4-fold), IL-6 (2.5- versus 9.3-fold), IL-8 (4.9- versus 8.6-fold), and IFN-γ (5- versus 9.5-fold). Antifoam activated complement and was avoided. PTF1+2 was generated in whole blood but not in plasma. In summary, air bubbles activated complement and triggered a C3-driven thromboinflammation. C3 inhibition reduced all mediators, whereas C5 inhibition reduced only TF-mRNA. Combined C5 and CD14 inhibition reduced IL-1β release. These data have implications for future mechanistic studies and possible pharmacological interventions in patients with air embolism.

Open chest and pericardium facilitate transpulmonary passage of venous air emboli

BACKGROUND

Transpulmonary passage of air emboli can lead to fatal brain- and myocardial infarctions. We studied whether pigs with open chest and pericardium had a greater transpulmonary passage of venous air emboli than pigs with closed thorax.

METHODS

We allocated pigs with verified closed foramen ovale to venous air infusion with either open chest with sternotomy and opening of the pleura and pericardium (n = 8) or closed thorax (n = 16). All pigs received a five-hour intravenous infusion of ambient air, starting at 4-6 mL/kg/h and increased by 2 mL/kg/h each hour. We assessed transpulmonary air passage by transesophageal M-mode echocardiography and present the results as median with inter-quartile range (IQR).

RESULTS

Transpulmonary air passage occurred in all pigs with open chest and pericardium and in nine pigs with closed thorax (56%). Compared to pigs with closed thorax, pigs with open chest and pericardium had a shorter to air passage (10 minutes (5-16) vs. 120 minutes (44-212), P < .0001), a smaller volume of infused air at the time of transpulmonary passage (12 mL (10-23) vs.170 mL (107-494), P < .0001), shorter time to death (122 minutes (48-185) vs 263 minutes (248-300, P = .0005) and a smaller volume of infused air at the time of death (264 mL (53-466) vs 727 mL (564-968), P = .001). In pigs with open chest and, infused air and time to death correlated strongly (r = 0.95, P = .001).

CONCLUSION

Open chest and pericardium facilitated the transpulmonary passage of intravenously infused air in pigs.

A successful new method for single left lobe recruitment

Any gas will flow down the path of least resistance and highest compliance. This is a problem in the treatment of severe unilateral lung disease in the intensive care unit (ICU). Deep sedation interferes with the diaphragm's ability to distribute air into the lower lung. Spontaneous breathing in a conscious patient, in combination with mechanical ventilation via an endotracheal tube inserted into the left main stem bronchus, can recruit collapsed alveoli.

Staphylococcus aureus-induced complement activation promotes tissue factor-mediated coagulation

Essentials Complement, Toll-like receptors and coagulation cross-talk in the process of thromboinflammation. This is explored in a unique human whole-blood model of S. aureus bacteremia. Coagulation is here shown as a downstream event of C5a-induced tissue factor (TF) production. Combined inhibition of C5 and CD14 efficiently attenuated TF and coagulation.

SUMMARY

Background There is extensive cross-talk between the complement system, the Toll-like receptors (TLRs), and hemostasis. Consumptive coagulopathy is a hallmark of sepsis, and is often mediated through increased tissue factor (TF) expression. Objectives To study the relative roles of complement, TLRs and TF in Staphylococcus aureus-induced coagulation. Methods Lepirudin-anticoagulated human whole blood was incubated with the three S. aureus strains Cowan, Wood, and Newman. C3 was inhibited with compstatin, C5 with eculizumab, C5a receptor 1 (C5aR1) and activated factor XII with peptide inhibitors, CD14, TLR2 and TF with neutralizing antibodies, and TLR4 with eritoran. Complement activation was measured by ELISA. Coagulation was measured according to prothrombin fragment 1 + 2 (PTF1 + 2 ) determined with ELISA, and TF mRNA, monocyte surface expression and functional activity were measured with quantitative PCR, flow cytometry, and ELISA, respectively. Results All three strains generated substantial and statistically significant amounts of C5a, terminal complement complex, PTF1 + 2 , and TF mRNA, and showed substantial TF surface expression on monocytes and TF functional activity. Inhibition of C5 cleavage most efficiently and significantly inhibited all six markers in strains Cowan and Wood, and five markers in Newman. The effect of complement inhibition was shown to be completely dependent on C5aR1. The C5 blocking effect was equally potentiated when combined with blocking of CD14 or TLR2, but not TLR4. TF blocking significantly reduced PTF1 + 2 levels to baseline levels. Conclusions S. aureus-induced coagulation in human whole blood was mainly attributable to C5a-induced mRNA upregulation, monocyte TF expression, and plasma TF activity, thus underscoring complement as a key player in S. aureus-induced coagulation.

Gas Embolism During Hysteroscopic Surgery?: Three Cases and a Literature Review

During a period of 1 month, 3 episodes of probable or actual venous air embolism occurred during hysteroscopic surgery. All patients developed the same symptoms of ventilatory and hemodynamic decompensation, beginning with a reduction in end-tidal carbon dioxide, arterial desaturation, and cyanosis on the upper trunk, and rapidly progressed to hypotension and 2 cardiac arrests. While entrainment of some air is common during hysteroscopy, life-threatening embolism is a rare but serious complication for which an anesthetist needs to be vigilant and prepared. If even a small drop in end-tidal carbon dioxide occurs, venous air embolism should be suspected and the operation should be discontinued.

Combined inhibition of C5 and CD14 efficiently attenuated the inflammatory response in a porcine model of meningococcal sepsis

Background

Fulminant meningococcal sepsis, characterized by overwhelming innate immune activation, mostly affects young people and causes high mortality. This study aimed to investigate the effect of targeting two key molecules of innate immunity, complement component C5, and co-receptor CD14 in the Toll-like receptor system, on the inflammatory response in meningococcal sepsis.

Methods

Meningococcal sepsis was simulated by continuous intravenous infusion of an escalating dose of heat-inactivated Neisseria meningitidis administered over 3 h. The piglets were randomized, blinded to the investigators, to a positive control group (n = 12) receiving saline and to an interventional group (n = 12) receiving a recombinant anti-CD14 monoclonal antibody together with the C5 inhibitor coversin.

Results

A substantial increase in plasma complement activation in the untreated group was completely abolished in the treatment group (p = 0.006). The following inflammatory mediators were substantially reduced in plasma in the treatment group: Interferon-γ by 75% (p = 0.0001), tumor necrosis factor by 50% (p = 0.01), Interleukin (IL)-8 by 50% (p = 0.03), IL-10 by 40% (p = 0.04), IL-12p40 by 50% (p = 0.03), and granulocyte CD11b (CR3) expression by 20% (p = 0.01).

Conclusion

Inhibition of C5 and CD14 may be beneficial in attenuating the detrimental effects of complement activation and modulating the cytokine storm in patients with fulminant meningococcal sepsis.

Systemic inflammation in acute intermittent porphyria: a case-control study

This study aimed to examine whether acute intermittent porphyria (AIP) is associated with systemic inflammation and whether the inflammation correlates with disease activity. A case-control study with 50 AIP cases and age-, sex- and place of residence-matched controls was performed. Plasma cytokines, insulin and C-peptide were analysed after an overnight fast using multiplex assay. Long pentraxin-3 (PTX3) and complement activation products (C3bc and TCC) were analysed using enzyme-linked immunosorbent assay (ELISA). Urine porphobilinogen ratio (U-PBG, µmol/mmol creatinine), haematological and biochemical tests were performed using routine methods. Questionnaires were used to register AIP symptoms, medication and other diseases. All 27 cytokines, chemokines and growth factors investigated were increased significantly in symptomatic AIP cases compared with controls (P < 0·0004). Hierarchical cluster analyses revealed a cluster with high visfatin levels and several highly expressed cytokines including interleukin (IL)-17, suggesting a T helper type 17 (Th17) inflammatory response in a group of AIP cases. C3bc (P = 0·002) and serum immunoglobulin (Ig)G levels (P = 0·03) were increased significantly in cases with AIP. The U-PBG ratio correlated positively with PTX3 (r = 0·38, P = 0·006), and with terminal complement complex (TCC) levels (r = 0·33, P = 0·02). PTX3 was a significant predictor of the biochemical disease activity marker U-PBG in AIP cases after adjustment for potential confounders in multiple linear regression analyses (P = 0·032). Prealbumin, C-peptide, insulin and kidney function were all decreased in the symptomatic AIP cases, but not in the asymptomatic cases. These results indicate that AIP is associated with systemic inflammation. Decreased C-peptide levels in symptomatic AIP cases indicate that reduced insulin release is associated with enhanced disease activity and reduced kidney function.

Combined inhibition of complement and CD14 improved outcome in porcine polymicrobial sepsis

Introduction

Sepsis is an exaggerated and dysfunctional immune response to infection. Activation of innate immunity recognition systems including complement and the Toll-like receptor family initiate this disproportionate inflammatory response. The aim of this study was to explore the effect of combined inhibition of the complement component C5 and the Toll-like receptor co-factor CD14 on survival, hemodynamic parameters and systemic inflammation including complement activation in a clinically relevant porcine model of polymicrobial sepsis.

Methods

Norwegian landrace piglets (4 ± 0.5 kg) were blindly randomized to a treatment group (n = 12) receiving the C5 inhibitor coversin (OmCI) and anti-CD14 or to a positive control group (n = 12) receiving saline. Under anesthesia, sepsis was induced by a 2 cm cecal incision and the piglets were monitored in standard intensive care for 8 hours. Three sham piglets had a laparotomy without cecal incision or treatment. Complement activation was measured as sC5b-9 using enzyme immunoassay. Cytokines were measured with multiplex technology.

Results

Combined C5 and CD14 inhibition significantly improved survival (p = 0.03). Nine piglets survived in the treatment group and four in the control group. The treatment group had significantly lower pulmonary artery pressure (p = 0.04) and ratio of pulmonary artery pressure to systemic artery pressure (p < 0.001). Plasma sC5b-9 levels were significantly lower in the treatment group (p < 0.001) and correlated significantly with mortality (p = 0.006). IL-8 and IL-10 were significantly (p < 0.05) lower in the treatment group.

Conclusions

Combined inhibition of C5 and CD14 significantly improved survival, hemodynamic parameters and inflammation in a blinded, randomized trial of porcine polymicrobial sepsis.

The key roles of complement and tissue factor in Escherichia coli-induced coagulation in human whole blood

The complement system and the Toll-like (TLR) co-receptor CD14 play important roles in innate immunity and sepsis. Tissue factor (TF) is a key initiating component in intravascular coagulation in sepsis, and long pentraxin 3 (PTX3) enhances the lipopolysaccharide (LPS)-induced transcription of TF. The aim of this study was to study the mechanism by which complement and CD14 affects LPS- and Escherichia coli (E. coli)-induced coagulation in human blood. Fresh whole blood was anti-coagulated with lepirudin, and incubated with ultra-purified LPS (100 ng/ml) or with E. coli (1 × 10(7) /ml). Inhibitors and controls included the C3 blocking peptide compstatin, an anti-CD14 F(ab')2 antibody and a control F(ab')2 . TF mRNA was measured using quantitative polymerase chain reaction (qPCR) and monocyte TF surface expression by flow cytometry. TF functional activity in plasma microparticles was measured using an amidolytic assay. Prothrombin fragment F 1+2 (PTF1.2) and PTX3 were measured by enzyme-linked immunosorbent assay (ELISA). The effect of TF was examined using an anti-TF blocking antibody. E. coli increased plasma PTF1.2 and PTX3 levels markedly. This increase was reduced by 84->99% with compstatin, 55-97% with anti-CD14 and > 99% with combined inhibition (P < 0·05 for all). The combined inhibition was significantly (P < 0·05) more efficient than compstatin and anti-CD14 alone. The LPS- and E. coli-induced TF mRNA levels, monocyte TF surface expression and TF functional activity were reduced by > 99% (P < 0·05) with combined C3 and CD14 inhibition. LPS- and E. coli-induced PTF1.2 was reduced by 76-81% (P < 0·05) with anti-TF antibody. LPS and E. coli activated the coagulation system by a complement- and CD14-dependent up-regulation of TF, leading subsequently to prothrombin activation.

Soluble CD14 is associated with markers of vascular dysfunction in bariatric surgery patients

BACKGROUND

Chronic endotoxemia has been proposed to contribute to obesity-related complications. We aimed to investigate the potential impact of lipopolysaccharide (LPS) and subsequent monocyte activation measured as soluble CD14 (sCD14) on markers of vascular dysfunction in obese subjects undergoing bariatric surgery.

METHODS

This was a prospective study of 49 obese patients and 17 controls, assessed by plasma levels of LPS, sCD14, asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA).

RESULTS

Levels of ADMA were increased in obese subjects compared to controls, but were not significantly reduced after bariatric surgery. In obese subjects at baseline, there was a significant trend to increasing levels of ADMA and SDMA through tertiles of sCD14 and decreasing levels of both markers through tertiles of LPS. In models adjusting for age and gender, sCD14 but not LPS remained independently associated with ADMA and SDMA. For every 10% age- and gender-adjusted increase in sCD14, ADMA increased 0.031 μM (5.6%), whereas SDMA increased 0.039 μM (10.8%).

CONCLUSIONS

Our results suggest that monocyte activation as measured by sCD14 is associated with obesity-related vascular dysfunction, whereas potential upstream triggers including microbial products should be investigated in future studies.

Combined inhibition of complement and CD14 efficiently attenuated the inflammatory response induced by Staphylococcus aureus in a human whole blood model

The complement and TLR systems are activated in sepsis, contributing to an unfavorable inflammatory "storm." Combined inhibition of these systems has been documented to efficiently attenuate the inflammatory responses induced by Gram-negative bacteria. In this study, we hypothesized that the combined inhibition would attenuate the inflammatory responses induced by Gram-positive bacteria. Staphylococcus aureus bacteria (strains Cowan and Wood), as well as S. aureus cell wall lipoteichoic acid (LTA), were incubated in thrombin-inhibited human whole blood. Complement was inhibited at the level of C3 and C5, and the TLRs by inhibiting CD14 and TLR2. Thirty-four inflammatory markers were measured by multiplex technology and flow cytometry. Thirteen markers increased significantly in response to Cowan and Wood, and 12 in response to LTA. Combined inhibition with the C3 inhibitor compstatin and the anti-CD14 Ab 18D11 significantly reduced 92 (Cowan, LTA) and 85% (Wood) of these markers. Compstatin alone significantly reduced 54 (Cowan), 38 (Wood), and 83% (LTA), whereas anti-CD14 alone significantly reduced 23, 15, and 67%, respectively. Further experiments showed that the effects of complement inhibition were mainly due to inhibition of C5a interaction with the C5a receptor. The effects on inhibiting CD14 and TLR2 were similar. The combined regimen was more efficient toward the bacterial effects than either complement or anti-CD14 inhibition alone. Complement was responsible for activation of and phagocytosis by both granulocytes and monocytes. Disrupting upstream recognition by inhibiting complement and CD14 efficiently attenuated S. aureus-induced inflammation and might be a promising treatment in both Gram-negative and Gram-positive sepsis.

Bradykinin analysis revived--a validated method for determination of its stable metabolite in whole blood by LC-MS/MS

Investigation of bradykinin involvement in diseases like hereditary angioedema has been greatly hindered by its rapid metabolism and generation, induced by sampling. Because of this, reliable measurements of bradykinin have yet to be introduced in clinical practice. Prevention of bradykinin generation during sampling, and determination of the in vivo generated stable metabolite BK1-5, should allow a reliable indirect measure of bradykinin involvement. An LC-MS/MS method has been developed to determine BK1-5 in human whole blood. The method inactivates metabolizing enzymes with ethanol, followed by solid phase extraction (C18), separation (C8) and detection (linear ion trap) through the transitions 287.25→320.20 (y3, quantifier), 408.20 (b4, qualifier) for BK1-5, and 292.17→330.20 (y3, quantifier), 408.20 (b4, qualifier) for the heavy labelled internal standard. The method showed acceptable linearity (n=3, r(2)=0.994), intra-run precision (CV<15%), inter-run precision (CV<15%) and accuracy (CV<14%), without matrix effects. LLOQ was 265.5 pmol L(-1) and LOD was 35.4 pmol L(-1). The method was used on blood samples from patients with hereditary angioedema, where BK1-5 was measured during attacks and in remision. The samples showed elevated concentrations (up to 1.7 nmol L(-1) during attacks and 265.5 pmol L(-1) in remission) compared to healthy volunteers (<35.4 pmol L(-1)). This is the first time BK1-5 in hereditary angioedema patients has been measured.

Plasma lipopolysaccharide is closely associated with glycemic control and abdominal obesity: evidence from bariatric surgery

OBJECTIVE

It is of vital importance to elucidate the triggering factors of obesity and type 2 diabetes to improve patient care. Bariatric surgery has been shown to prevent and even cure diabetes, but the mechanism is unknown. Elevated levels of lipopolysaccharide (LPS) predict incident diabetes, but the sources of LPS are not clarified. The objective of the current study was to evaluate the potential impact of plasma LPS on abdominal obesity and glycemic control in subjects undergoing bariatric surgery.

RESEARCH DESIGN AND METHODS

This was a prospective observational study involving a consecutive sample of 49 obese subjects undergoing bariatric surgery and 17 controls. Main assessments were plasma LPS, HbA1c, adipose tissue volumes (computed tomography), and quantified bacterial DNA in adipose tissue compartments.

RESULTS

Plasma levels of LPS were elevated in obese individuals compared with controls (P < 0.001) and were reduced after bariatric surgery (P = 0.010). LPS levels were closely correlated with HbA1c (r = 0.56; P = 0.001) and intra-abdominal fat volumes (r = 0.61; P < 0.001), but only moderately correlated with subcutaneous fat volumes (r = 0.33; P = 0.038). Moreover, there was a decreasing gradient (twofold) in bacterial DNA levels going from mesenteric via omental to subcutaneous adipose tissue compartments (P = 0.041). Finally, reduced LPS levels after bariatric surgery were directly correlated with a reduction in HbA1c (r = 0.85; P < 0.001).

CONCLUSIONS

Our findings support a hypothesis of translocated gut bacteria as a potential trigger of obesity and diabetes, and suggest that the antidiabetic effects of bariatric surgery might be mechanistically linked to, and even the result of, a reduction in plasma levels of LPS.

C1-inhibitor efficiently inhibits Escherichia coli-induced tissue factor mRNA up-regulation, monocyte tissue factor expression and coagulation activation in human whole blood

Both the complement system and tissue factor (TF), a key initiating component of coagulation, are activated in sepsis, and cross-talk occurs between the complement and coagulation systems. C1-inhibitor (C1-INH) can act as a regulator in both systems. Our aim in this study was to examine this cross-talk by investigating the effects of C1-INH on Escherichia coli-induced haemostasis and inflammation. Fresh human whole blood collected in lepirudin was incubated with E. coli or ultrapurified E. coli lipopolysaccharide (LPS) in the absence or presence of C1-INH or protease-inactivated C1-INH. C3 activation was blocked by compstatin, a specific C3 convertase inhibitor. TF mRNA was measured using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and TF surface expression was measured by flow cytometry. In plasma, the terminal complement complex, prothrombin F1·2 (PTF1·2) and long pentraxin 3 (PTX3) were measured by enzyme-linked immunosorbent assay (ELISA). Cytokines were analysed using a multiplex kit. C1-INH (1·25-5 mg/ml) reduced both LPS- and E. coli-induced coagulation, measured as a reduction of PTF1·2 in plasma, efficiently and dose-dependently (P < 0·05). Both LPS and E. coli induced marked up-regulation of TF mRNA levels and surface expression on whole blood monocytes. This up-regulation was reduced efficiently by treatment with C1-INH (P < 0·05). C1-INH reduced the release of PTX3 (P < 0·05) and virtually all cytokines measured (P < 0·05). Complement activation was inhibited more efficiently with compstatin than with C1-INH. C1-INH inhibited most of the other readouts more efficiently, consistent with additional non-complement-dependent effects. These results indicate that complement plays a role in activating coagulation during sepsis and that C1-INH is a broad-spectrum attenuator of the inflammatory and haemostatic responses.

The effects of selective complement and CD14 inhibition on the E. coli-induced tissue factor mRNA upregulation, monocyte tissue factor expression, and tissue factor functional activity in human whole blood

BACKGROUND

The complement pathway and CD14 play essential roles in inflammation, but little is known about the relative roles of complement and CD14 in E. coli-induced tissue factor (TF) mRNA upregulation, expression by monocytes, and functional activity in human whole blood.

METHODS

Whole E. coli bacteria were incubated for up to 4 h in human whole blood containing the anticoagulant lepirudin, which does not affect complement activation. TF mRNA levels were analyzed using reverse transcription, quantitative real-time PCR (RT-qPCR), and the expression of TF on the cell surface was analyzed using flow cytometry. Complement was selectively inhibited using the C3 convertase inhibitor compstatin or a C5a receptor antagonist (C5aRa), while CD14 was blocked by an anti-CD14 F(ab')2 monoclonal antibody.

RESULTS

The E. coli-induced TF mRNA upregulation was reduced to virtually background levels by compstatin, whereas anti-CD14 had no effect. Monocyte TF expression and TF activity in plasma microparticles were significantly reduced by C5aRa. Anti-CD14 alone only slightly reduced E. coli-induced monocyte TF expression but showed a modest additive effect when combined with the complement inhibitors. Inhibiting complement and CD14 efficiently reduced the expression of the E. coli-induced cytokines IL-1beta, IL-6, IL-8, and platelet-derived growth factor bb.

CONCLUSION

Our results indicate that E. coli-induced TF mRNA upregulation is mainly dependent on complement activation, while CDI4 plays a modest role in monocyte TF expression and the plasma TF activity in human whole blood.

"Fighting the system": families caring for ventilator-dependent children and adults with complex health care needs at home

Background

An increasing number of individuals with complex health care needs now receive life-long and life-prolonging ventilatory support at home. Family members often take on the role of primary caregivers. The aim of this study was to explore the experiences of families giving advanced care to family members dependent on home mechanical ventilation.

Methods

Using qualitative research methods, a Grounded Theory influenced approach was used to explore the families' experiences. A total of 15 family members with 11 ventilator-dependent individuals (three children and eight adults) were recruited for 10 in-depth interviews.

Results

The core category, "fighting the system," became the central theme as family members were asked to describe their experiences. In addition, we identified three subcategories, "lack of competence and continuity", "being indispensable" and "worth fighting for". This study revealed no major differences in the families' experiences that were dependent on whether the ventilator-dependent individual was a child or an adult.

Conclusions

These findings show that there is a large gap between family members' expectations and what the community health care services are able to provide, even when almost unlimited resources are available. A number of measures are needed to reduce the burden on these family members and to make hospital care at home possible. In the future, the gap between what the health care can potentially provide and what they can provide in real life will rapidly increase. New proposals to limit the extremely costly provision of home mechanical ventilation in Norway will trigger new ethical dilemmas that should be studied further.

Home mechanical ventilation and specialised health care in the community: Between a rock and a hard place

Background

Home mechanical ventilation probably represents the most advanced and complicated type of medical treatment provisioned outside a hospital setting. The aim of this study was both to explore the challenges experienced by health care professionals in community health care services when caring for patients dependent on home mechanical ventilation, continual care and highly advanced technology, and their proposed solutions to these challenges.

Methods

Using qualitative research methods, a grounded theory influenced approach was used to explore the respondents' experiences and proposed solutions. A total of 34 multidisciplinary respondents from five different communities in Norway were recruited for five focus groups.

Results

The core category in our findings was what health care professionals in community health care services experience as "between a rock and a hard place," when working with hospitals, family members, and patients. We further identified four subcategories, "to be a guest in the patient's home," "to be accepted or not," "who decides," and "how much can we take." The main background for these challenges seems to stem from patients living and receiving care in their private homes, which often leads to conflicts with family members. These challenges can have a negative effect on both the community health caregivers' work environment and the community health service's provision of professional care.

Conclusions

This study has identified that care of individuals with complex needs and dependent on home mechanical ventilation presents a wide range of immense challenges for community health care services. The results of this study point towards a need to define the roles of family caregivers and health care professionals and also to find solutions to improve their collaboration. The need to improve the work environment for caregivers directly involved in home-care also exists. The study also shows the need for more dialogue concerning eligibility requirements, rights, and limitations of patients in the provision and use of ventilatory support in private homes.

2010 International consensus algorithm for the diagnosis, therapy and management of hereditary angioedema

BACKGROUND

We published the Canadian 2003 International Consensus Algorithm for the Diagnosis, Therapy, and Management of Hereditary Angioedema (HAE; C1 inhibitor [C1-INH] deficiency) and updated this as Hereditary angioedema: a current state-of-the-art review: Canadian Hungarian 2007 International Consensus Algorithm for the Diagnosis, Therapy, and Management of Hereditary Angioedema.

OBJECTIVE

To update the International Consensus Algorithm for the Diagnosis, Therapy and Management of Hereditary Angioedema (circa 2010).

METHODS

The Canadian Hereditary Angioedema Network (CHAEN)/Réseau Canadien d'angioédème héréditaire (RCAH) http://www.haecanada.com and cosponsors University of Calgary and the Canadian Society of Allergy and Clinical Immunology (with an unrestricted educational grant from CSL Behring) held our third Conference May 15th to 16th, 2010 in Toronto Canada to update our consensus approach. The Consensus document was reviewed at the meeting and then circulated for review.

RESULTS

This manuscript is the 2010 International Consensus Algorithm for the Diagnosis, Therapy and Management of Hereditary Angioedema that resulted from that conference.

CONCLUSIONS

Consensus approach is only an interim guide to a complex disorder such as HAE and should be replaced as soon as possible with large phase III and IV clinical trials, meta analyses, and using data base registry validation of approaches including quality of life and cost benefit analyses, followed by large head-to-head clinical trials and then evidence-based guidelines and standards for HAE disease management.

Disease expression in women with hereditary angioedema

OBJECTIVE

Fluctuations in sex hormones can trigger angioedema attacks in women with hereditary angioedema. Combined oral contraceptive therapies, as well as pregnancy, can induce severe attacks. The course of angioedema may be very variable in different women.

STUDY DESIGN

Within the PREHAEAT project launched by the European Union, data on 150 postpubertal women with hereditary angioedema were collected in 8 countries, using a patient-based questionnaire.

RESULTS

Puberty worsened the disease for 62%. Combined oral contraceptives worsened the disease for 79%, whereas progestogen-only pills improved it for 64%. During pregnancies, 38% of women had more attacks, but 30% had fewer attacks. Vaginal delivery was usually uncomplicated. Attacks occurred within 48 hours in only 6% of cases. Those more severely affected during menses had more symptoms during pregnancies, suggesting a hormone-sensitive phenotype for some patients.

CONCLUSION

The course of angioedema in women with C1 inhibitor deficiency is affected by physiologic hormonal changes; consequently, physicians should take these into account when advising on management.

A young man with acute dilated cardiomyopathy associated with methylphenidate

An 18-year-old obese man with a body mass index of 40, diagnosed with attention-deficit hyperactivity disorder and treated with methylphenidate (Concerta^®) was acutely admitted to hospital with hypoxia and dyspnoea. On investigation signs of liver-, renal-, and heart-failure were found. Noradrenalin infusion was started. Echocardiography showed dilated left ventricle and an ejection fraction (EF) of 25%. Liver function improved, noradrenalin and dobutamine were tapered, but three days after admission a new echocardiography showed an EF of 10%. The patient was transferred to the National Hospital (Rikshospitalet, Oslo), where intensified treatment including intra aortic balloon pump (IABP) was instituted. Cardiac function improved, and 3 weeks later the IABP was disconnected. EF at this point was 15%. The patient was denied heart transplantation due to various cofactors. The investigation concluded with a probable relationship between his cardiomyopathy and the use of methylphenidate (Concerta).

Tryptase levels after suxamethonium administration and defibrillation

BACKGROUND

A more than threefold increase in tryptase, when comparing with the control sample, strengthens the diagnosis of anaphylaxis. Trauma, coronary ischaemia and non-IgE-mediated reactions to several medications have been shown to cause more than threefold rise in tryptase levels. The aim of our study was to examine whether suxamethonium or defibrillation could lead to a more than threefold increase in tryptase in the absence of signs of anaphylaxis.

METHODS

S-tryptase was measured in 50 patients who had general anaesthesia with either pentothal and suxamethonium before electro convulsive therapy (ECT) to treat depression (n=31) or propofol before electro conversion to treat atrial fibrillation (n=19). Blood samples were collected minutes before and 1 h after the procedures.

RESULTS

Tryptase values did not differ significantly before and after the procedures.

CONCLUSION

Tryptase levels do not increase in patients undergoing elective defibrillation or ECT with the administration of suxamethonium, in absence of symptoms of anaphylaxis.

New biomarkers in an acute model of live Escherichia coli-induced sepsis in pigs

We developed a live Escherichia coli model of acute sepsis in pigs with emphasize on biomarkers reflecting the early inflammatory response of sepsis. Healthy pigs, 25-35 kg, were challenged intravenously (IV) (n = 12) or intrapulmonary (n = 6) with live E. coli and observed for 3 and 5 h respectively. Control pigs received culture medium (n = 6 + 3). Haemodynamic parameters and a broad panel of inflammatory mediators were measured. The dose of bacteria was carefully titrated to obtain a condition resembling the early phase of human septic shock. The IV group displayed a pro-inflammatory response [significant increase in tumour necrosis factor-alpha, interleukin (IL)-6 and IL-8] and an early anti-inflammatory response (significant increase in IL-10). For the first time, we demonstrate a significant increase in IL-12 and matrix metalloproteinase-9 (MMP) early in pig sepsis. Coagulation was activated (significant increase in thrombin-antithrombin complexes) and there was a significant decrease in the serum proteins suggesting capillary leakage. Haemodynamic parameters reflected a septic condition with significant decrease in systemic blood pressure, increases in heart rate, pulmonary artery pressure and base deficit. None of these changes was observed in the control group. Interleukin-1beta and vascular endothelial growth factor increased in both groups. Nitric oxide measurements suggested an initial pulmonary vascular endothelial inflammatory response. The intrapulmonary group, which did not resemble septic condition, showed a substantial increase in MMP-9. In this porcine model of sepsis, IL-12 and MMP-9 were detected for the first time. These biomarkers may have an impact in the understanding and future treatment of sepsis.

Hereditary angiodema: a current state-of-the-art review, VII: Canadian Hungarian 2007 International Consensus Algorithm for the Diagnosis, Therapy, and Management of Hereditary Angioedema

BACKGROUND

We published the Canadian 2003 International Consensus Algorithm for the Diagnosis, Therapy, and Management of Hereditary Angioedema (HAE; C1 inhibitor [C1-INH] deficiency) in 2004.

OBJECTIVE

To ensure that this consensus remains current.

METHODS

In collaboration with the Canadian Network of Rare Blood Disorder Organizations, we held the second Canadian Consensus discussion with our international colleagues in Toronto, Ontario, on February 3, 2006, and reviewed its content at the Fifth C1 Inhibitor Deficiency Workshop in Budapest on June 2, 2007. Papers were presented by international investigators, and this consensus algorithm approach resulted.

RESULTS

This consensus algorithm outlines the approach recommended for the diagnosis, therapy, and management of HAE, which was agreed on by the authors of this report. This document is only a consensus algorithm approach and continues to require validation. As such, participants agreed to make this a living 2007 algorithm, a work in progress, and to review its content at future international HAE meetings.

CONCLUSIONS

There is a paucity of double-blind, placebo-controlled trials on the treatment of HAE, making levels of evidence to support the algorithm less than optimal. Controlled trials currently under way will provide further insight into the management of HAE. As with our Canadian 2003 Consensus, this 2007 International Consensus Algorithm for the Diagnosis, Therapy, and Management of HAE was formed through the meeting and agreement of patient care professionals along with patient group representatives and individual patients.

Angioedema from angiotensin-converting enzyme (ACE) inhibitor treated with complement 1 (C1) inhibitor concentrate

BACKGROUND

Up to seven in every 1000 patients experience angioedema from angiotensin-converting enzyme (ACE) inhibitors, even after many years of use. In 2003, every 20th Norwegian used an ACE inhibitor.

CASE REPORT

A 61-year-old woman with chronic obstructive pulmonary disease and a past acute myocardial infarction had used 7.5 mg of ramipril daily for the past 7 years. She also used acetylsalicylic acid, simvastatin, theophylline and salmeterol. One night she woke up with edema of the tongue. On hospital arrival, 250 mg of hydrocortisone and 5 mg of dexchlorpheniramine were given intravenously (i.v.) and 0.3 mg of epinephrine was given subcutaneously (s.c.). The edema of the tongue progressed over the next 8 h and made the tongue protrude. Fiberscopy revealed glassy edema of the arytenoids. Inspiratory stridor was heard and the patient could not speak. She became increasingly uneasy and restless. Berinert complement 1 (C1) inhibitor concentrate (1500 units) was administered i.v. Over the following 20 min, stridor gradually subsided, the patient calmed and she was able to talk.

DISCUSSION

ACE inhibitor-provoked angioedema shares many clinical features with hereditary angioedema (HAE), including a limited effect of steroids, antihistamines and epinephrine. HAE, caused by excess bradykinin formation as a result of C1 inhibitor deficiency, usually has its laryngeal edema effectively reversed by C1 inhibitor in less than 0.5 h. Although patients experiencing ACE inhibitor-provoked angioedema have normal C1 inhibitor values, as in our patient, excess bradykinin is probably important as ACE breaks down bradykinin. It is unknown why ACE inhibitor-provoked angioedema appears in some and sometimes after many years of use.

CONCLUSION

We believe that C1 inhibitor was effective in reversing the ACE inhibitor-induced angioedema in our patient.

Hypotensive shock and angio-oedema from angiotensin II receptor blocker: a class effect in spite of tripled tryptase values

In adverse reactions with shock, tripled tryptase values can support a diagnosis of anaphylaxis. A 51-year old physically fit woman experienced angio-oedema and hypotensive shock after irbesartan ingestion requiring noradrenaline infusion. Serum tryptase rose to three times the normal value. Total immunoglobulin E and skin prick tests were normal, however. As nonallergic increases in tryptase have been observed, e.g. during angio-oedema from angiotensin-converting enzyme inhibitors, and bradykinin itself can degranulate mast cells acutely, we interpret the reaction as a class effect. To our knowledge, our report is one of the first on shock and angio-oedema from irbesartan.

Neuroleptic malignant syndrome with severe liver failure

A schizophrenic patient on long-time neuroleptic medication was admitted with ileus. Secondarily, a high fever, rigidity, mental confusion, tachycardia and hypotension developed. After bromocriptine was given, the temperature dropped by 2 degrees C and the patient improved markedly. A diagnosis of neuroleptic malignant syndrome was made. Five years later she was re-admitted with similar symptoms and also severe liver failure. Meanwhile the discontinued neuroleptic medication had been reinstituted. Again bromocriptine reduced the temperature of approximately 2 degrees C, and was paralleled by a normalization of liver function. To our knowledge this is the second report on severe liver failure in conjunction with neuroleptic malignant syndrome. The efficacy of bromocriptine in the treatment of this syndrome is underlined.

Mechanism of complement activation and its role in the inflammatory response after thoracoabdominal aortic aneurysm repair

BACKGROUND

Complement activation contributes to ischemia-reperfusion injury. Patients undergoing thoracoabdominal aortic aneurysm (TAAA) repair suffer extensive ischemia-reperfusion and considerable systemic inflammation.

METHODS AND RESULTS

The degree and mechanism of complement activation and its role in inflammation were investigated in 19 patients undergoing TAAA repair. Patients undergoing open infrarenal aortic surgery (n=5) or endovascular descending aortic aneurysm repair (n=6) served as control subjects. Substantial complement activation was seen in TAAA patients but not in controls. C1rs-C1-inhibitor complexes increased moderately, whereas C4bc, C3bBbP, C3bc, and the terminal SC5b-9 complex (TCC) increased markedly after reperfusion, reaching a maximum 8 hours after reperfusion. Interleukin (IL)-1beta, tumor necrosis factor alpha (TNF-alpha), and IL-8 increased significantly in TAAA patients but not in controls, peaking at 24 hours postoperatively and correlating closely with the degree of complement activation. IL-6 and IL-10 increased to a maximum 8 hours after reperfusion in the TAAA patients, were not correlated with complement activation, and increased moderately in the control subjects. Myeloperoxidase and lactoferrin increased markedly before reperfusion in all groups, whereas sICAM-1, sP-selectin, and sE-selectin were unchanged. No increase was observed in complement activation products, IL-1beta, TNF-alpha, or IL-8 in a mannose-binding lectin (MBL)-deficient TAAA patient, whereas IL-6, IL-10, myeloperoxidase, and lactoferrin increased as in the controls. Two other MBL-deficient TAAA patients receiving plasma attained significant MBL levels and showed complement and cytokine patterns identical to the MBL-sufficient TAAA patients.

CONCLUSIONS

The data suggest that complement activation during TAAA repair is MBL mediated, amplified through the alternative pathway, and responsible in part for the inflammatory response.

C1-inhibitor reduces the ischaemia-reperfusion injury of skeletal muscles in mice after aortic cross-clamping

BACKGROUND

Both C1-inhibitor (C1-INH) and antibodies against the CD18 adhesion molecule have been shown to reduce ischaemia-reperfusion injuries. The objective of this study was to investigate the effect of increased ischaemia times and to determine whether inhibiting C1 or blocking the CD18 function was protective in skeletal muscle ischaemia-reperfusion injury after aortic cross-clamping.

MATERIALS AND METHODS

BALB/c mice were subjected to aortic cross-clamping below the renal artery for 60, 75 or 105 min, followed by 3 h of reperfusion. Two-thirds of a total dose of anti-CD18 antibody (40 mg/kg) or human C1-INH (1,000 IU/kg) was given by intraperitoneal injection before ischaemia and one-third immediately after the clamping. Creatine kinase (CK) in the plasma was used as an indicator of muscle injury severity.

RESULTS

There was a consistent rise in the plasma CK concentration proportional to the length of ischaemia (P < 0.0005). C1-INH treatment significantly (P = 0.012) reduced the plasma CK for the ischaemia times of 75 and 105 min. The anti-CD18 antibody did not have any effect, as demonstrated by the CK values that were similar to controls (P = 0.836).

CONCLUSION

The data support a beneficial role for C1-INH in the treatment of ischaemia-reperfusion injuries of skeletal muscles.

When is an anesthesiologist needed in a helicopter emergency medical service in northern Norway?

BACKGROUND

A national air ambulance service, including helicopters and airplanes, was implemented in Norway in 1988. The main intention was to offer advanced medical services when needed. All helicopters are manned by anesthesiologists. Catchment areas for the 11 helicopters span from cities to scarcely populated areas, particularly in the north. Our aim was to assess what proportion of ambulance missions carried out by the rescue helicopter in Bodø, northern Norway, delivered advanced medical treatment needing the skills of an anesthesiologist.

METHODS

Flight and ambulance records (n = 2078) from 1988 and 1990-98 (10 years) were analyzed retrospectively. Inter-hospital transfers (n = 147) and search- and rescue missions (n = 332) were not included. According to the level of medical treatment given missions were categorized into three groups (A, B and C). Treatment in groups A and B would not require an anesthesiologist.

RESULTS

Two thousand and seventy-eight ambulance missions carried 2166 patients (114 per 100 000 per year). Median take-off and on-scene times were 29 and 55 min, respectively. Seven hundred and fifty-five patients (35%) suffered from cardiovascular disease, 495 (23%) were injured and 250 (12%) were parturients. One hundred and seven patients (5.0%) received advanced prehospital emergency treatment requiring an anesthesiologist. Forty-five of the 107 patients survived to discharge from hospital, amongst whom 28 had received intravenous nitroglycerin for angina or suspected myocardial infarction.

CONCLUSION

In our rural area, with a widely scattered population, 95% of patients received medical treatment not requiring an anesthesiologist. A selective use of the anesthesiologist seems indicated.

Expression of active human C1 inhibitor serpin domain in Escherichia coli

Human C1 inhibitor is a highly glycosylated serine protease inhibitor of the serpin family. The protein contains two disulfide bonds. In this study, an N-terminally truncated form of recombinant C1 inhibitor was overexpressed in Escherichia coli strains BL21(DE3) and AD494(DE3), the latter enabling the formation of disulfide bonds within the cytoplasm. With both strains, a major fraction of the recombinant protein produced appeared to be insoluble. However, the soluble fraction of lysates from strain AD494(DE3) inhibited the C1s target protease in functional assays. Recombinant C1 inhibitor produced in this strain also displayed the ability to complex with C1s in vitro. In contrast, lysates from strain BL21(DE3) displayed no C1 inhibitor activity. These data support the notion that glycosylation is not important, whereas disulfide bond formation appears to be essential for the production of an active recombinant C1 inhibitor. Thus, bacterial strains that permit the formation of disulfide bonds may represent a reliable system for the production of recombinant C1 inhibitor. However, a major obstacle to large-scale production will be to produce the protein in a soluble form. Attempts to increase the yield of soluble protein by coexpression of the GroEL/ES chaperonins resulted in an increase in solubility.

[Coronary angiography in a county hospital]

BACKGROUND

At a county hospital in northern Norway, coronary angiographies have been performed for more than 25 years. We wanted to compare our complication rates with results from larger hospitals.

MATERIAL AND METHODS

Data concerning indication for angiography, findings and complications were collected retrospectively from the files of 837 patients who underwent coronary angiography at our hospital during the last ten years. The number of procedures per year has varied from 30 to 125.

RESULTS

50% of the patients had three-vessel and/or left main coronary artery stenosis. Less than 10% of the patients had no significant coronary stenosis or valvular disease at angiography. The total complication rate was 4.8%. Nine patients (1.1%) had myocardial infarction or stroke with sequelae; three patients died (0.4%).

INTERPRETATION

Our complication rates are higher than those from other larger hospitals in Norway and internationally, but they have decreased over time. The high percentage of serious coronary pathology among our patients may have contributed significantly to the complication rate. In addition, the annual number of exams may have been too low to give sufficient operator training. The results require a continuing evaluation of our practice.

[Coronary angiography in a county hospital]

BACKGROUND

At a county hospital in northern Norway, coronary angiographies have been performed for more than 25 years. We wanted to compare our complication rates with results from larger hospitals.

MATERIAL AND METHODS

Data concerning indication for angiography, findings and complications were collected retrospectively from the files of 837 patients who underwent coronary angiography at our hospital during the last ten years. The number of procedures per year has varied from 30 to 125.

RESULTS

50% of the patients had three-vessel and/or left main coronary artery stenosis. Less than 10% of the patients had no significant coronary stenosis or valvular disease at angiography. The total complication rate was 4.8%. Nine patients (1.1%) had myocardial infarction or stroke with sequelae; three patients died (0.4%).

INTERPRETATION

Our complication rates are higher than those from other larger hospitals in Norway and internationally, but they have decreased over time. The high percentage of serious coronary pathology among our patients may have contributed significantly to the complication rate. In addition, the annual number of exams may have been too low to give sufficient operator training. The results require a continuing evaluation of our practice.

[Check list for the use of thrombolytics and other drugs in acute myocardial infarction]

MATERIALS AND METHODS

Data on all patients with acute myocardial infarction who were treated in Nordland County Hospital in a six-month period in 1996 were analyzed retrospectively (137 patients). After the introduction of checklists for the treatment of such patients, we did a prospective six-month registration in 1997 (111 patients) in order to find out whether treatment and delay times had improved.

RESULTS

The proportion of patients who received thrombolytic treatment did not change (28% in 1996 as compared to 25% in 1997). The in-hospital delay time before treatment did not differ before and after the introduction of a check-list (approximately 40 minutes in both periods). There was an increase in the use of intravenous beta blockers and aspirin.

INTERPRETATION

The percentage of patients with acute myocardial infarction receiving thrombolytics in our hospital does not differ substantially from that of other hospitals in Norway.

Complement activation in patients with systemic lupus erythematosus without nephritis

OBJECTIVE

To study the association between disease activity and complement activation prospectively in patients with systemic lupus erythematosus (SLE).

PATIENTS AND METHODS

Twenty-one SLE patients were examined monthly for 1 yr. Disease activity, autoantibodies, conventional complement tests and the following complement activation products were investigated: C1rs-C1inh complexes, C4bc, Bb, C3a, C3bc, C5a and the terminal SC5b-9 complement complex (TCC).

RESULTS

Modest variation in disease activity was noted. None of the patients had nephritis. Flare was observed at 27 visits. Four patients had anti-C1q antibodies in conjunction with modestly low C1q concentrations. The complement parameters were rather constant during the observation period. Slightly to moderately decreased C4 (0.05-0.10 g/l) was found in 10 patients and severely decreased C4 (<0.05 g/l) in seven patients. Decreased C4 was not associated with increased complement activation. Complement activation products were either normal or slightly elevated. TCC was the only activation product correlating significantly with score for disease activity at flare. None of the variables tested predicted flares.

CONCLUSION

Complement tests are of limited importance in routine examination of SLE without nephritis, although TCC is suggested to be one of the most sensitive markers for disease activity.

C1-inhibitor attenuates hyperacute rejection and inhibits complement, leukocyte and platelet activation in an ex vivo pig-to-human perfusion model

Xenotransplantation may be a future alternative due to increased shortage of organs. Classical complement activation is central in hyperacute rejection in pig-to-human combinations. We investigated the effects of C1-inhibitor (C1-INH), a regulator of the complement and contact systems, on hyperacute rejection. Pig kidneys were perfused with fresh human blood to which either C1-INH (n = 6) or human serum albumin (n = 6) was added. The survival of the C1-INH perfused kidneys (mean 327 min) was significantly longer (p < 0.00001) than the controls (79 min). C1-INH substantially inhibited complement activation (C1rs-C1-INH complexes, C4bc, C3bc and terminal complement complex) (p < 0.001 for all) compared with the marked complement activation in the controls. No contact activation was found. Leukocytes and platelets were substantially activated (counts, myeloperoxidase, beta-thromboglobulin, thrombospondin, soluble P-selectin) in the control group, and this activation was markedly reduced by C1-INH (p < 0.02 for all). Immunohistochemistry showed less C1q, C3, TCC, IgG and fibrin deposition in the C1-INH group. C1-INH may be useful to attenuate hyperacute rejection, probably through inhibition of complement. The reduced activation of neutrophils and platelets may mainly be secondary to inhibition of complement.

[Hereditary exostoses--presentation of a family case]

In this article we present a Norwegian family with hereditary multiple exostoses and a review of relevant literature. 21 family members were examined; ten males and six females had multiple exostoses, the youngest from six months of age. The exostoses had led to compression of nerves, disturbance of bone growth with shortening and bowing of the forearm bones, and valgus deformity of the knee and ankle. Physical function and quality of life was generally well preserved. Contrary to most reports, nearly half of the patients had allegedly noticed growth or debut of exostoses in adulthood. Almost half of the patients had had the exostoses removed surgically twice, (median value). Malignant transformation of exostoses has not been observed in the family.

High-dose intravenous immunoglobulin treatment activates complement in vivo

Several complement modulating effects of high-dose intravenous immunoglobulins (IVIG) have been proposed from in vitro studies and experimental animal models. However, the in vivo effects of IVIG on plasma complement in humans are yet not known. We have investigated the in vivo effects of IVIG on complement in seven women with unexplained recurrent spontaneous abortion who were without evidence of autoimmune disease. Samples were obtained before and after the very first infusion of IVIG. There was a marked increase in immunoglobulin G (IgG) from (median and range) 12.4 (9.4-15.9) to 26.8 (22.4-30.0) g/l but no change in immunoglobulin A (IgA) or immunoglobulin M (IgM). A significantly increased complement activation was demonstrated using neoepitope-specific enzyme immunoassays to the activation products C3bc (median increased from 9.8 to 31.2 AU/ml), Bb (0.66-1.66 g/ml), C5a (10.5-12.7 ng/ml), and TCC (0.81-2.19 AU/ml) (P = 0.015 for all). There were no changes in antigenic concentrations of individual complement components or regulators (C1q, C4, C3, C1-inhibitor, C4b-binding protein) and no decrease in complement haemolytic activity (classical and alternative CH50), which were all within the normal range. The classical pathway activation products C1rs/C1-inhibitor complexes, C4bc and C4d were elevated in all patients before IVIG treatment and did not change significantly during treatment. In conclusion, IVIG induced a significant activation of complement in vivo.

[Blood pressure measurements using three different cuff sizes]

The use of blood pressure cuffs containing bladders of appropriate size for the arm is a known prerequisite for correct blood pressure measurements. The Tricuff, containing three inflatable bladders of varying dimensions, one of which is automatically selected to fit the arm circumference, was compared to a standard cuff (12 x 35 cm) in 137 persons. In persons with large arms (circumference > or = 32 cm) measurement with the Tricuff showed on average 19.2 mm Hg lower systolic pressure and 12.9 mm Hg lower diastolic pressure than with the standard cuff. In persons with small arms (< 32 cm) the corresponding differences were 9.0 mm Hg and 7.5 mm Hg. Compared to the Tricuff, the standard cuff overestimates blood pressure in people with a large arm circumference. Overestimation may also be caused by the rubber bladder bulging more from below the standard soft nylon cuff than what the firmer texture of the Tricuff allows, resulting in falsely high values even in persons with normal arm circumference.

[Reflexes in brain-dead patients]

We report on a patient who suffered an acute, extensive intracerebral haemorrhage, leading to symptoms of cerebral herniation within a few hours. The clinical diagnosis of brain death was made based on a neurological examination, and an apnoea test eight hours after the haemorrhage. A few hours later the diagnosis was changed, as several reflexes reappeared. After six days mechanical ventilation was withdrawn, as the brain damage was considered so serious as to render further therapy futile. It was considered unethical to sustain therapy for a possible organ donation at a later date. A review of relevant the literature, however, shows that brain-dead patients may exhibit such varying degrees of autonomic and spinal reflexes as to cause confusion, thus delaying the physician in making a diagnosis. Often, an opportunity for organ donation is lost. Based on this review, we believe that our patient was indeed brain dead when the first diagnosis was made, and that a cerebral angiography should have been performed. Because organ donation is an important issue, the diagnosis of brain death must be definitive.