Effectiveness of uterine tamponade devices for refractory postpartum haemorrhage after vaginal birth: a systematic review.

OBJECTIVES: To evaluate uterine tamponade devices' effectiveness for atonic refractory postpartum haemorrhage (PPH) after vaginal birth and the effect of including them in institutional protocols. SEARCH STRATEGY: PubMed, EMBASE, CINAHL, LILACS, POPLINE, from inception to January 2021. STUDY SELECTION: Randomised and non-randomised comparative studies. OUTCOMES: Composite outcome including surgical interventions (artery ligations, compressive sutures or hysterectomy) or maternal death, and hysterectomy. RESULTS: All included studies were at high risk of bias. The certainty of the evidence was rated as very low to low. One randomised study measured the effect of the condom-catheter balloon compared with standard care and found unclear results for the composite outcome (relative risk [RR] 2.33, 95% CI 0.76-7.14) and hysterectomy (RR 4.14, 95% CI 0.48-35.93). Three comparative studies assessed the effect of including uterine balloon tamponade in institutional protocols. A stepped wedge cluster randomised controlled trial suggested an increase in the composite outcome (RR 4.08, 95% CI 1.07-15.58) and unclear results for hysterectomy (RR 4.38, 95% CI 0.47-41.09) with the use of the condom-catheter or surgical glove balloon. One non-randomised study showed unclear effects on the composite outcome (RR 0.33, 95% CI 0.11-1.03) and hysterectomy (RR 0.49, 95% CI 0.04-5.38) after the inclusion of the Bakri balloon. The second non-randomised study found unclear effects on the composite outcome (RR 0.95, 95% CI 0.32-2.81) and hysterectomy (RR 1.84, 95% CI 0.44-7.69) after the inclusion of Ebb or Bakri balloon. CONCLUSIONS: The effect of uterine tamponade devices for the management of atonic refractory PPH after vaginal delivery is unclear, as is the role of the type of device and the setting. TWEETABLE ABSTRACT: Unclear effects of uterine tamponade devices and their inclusion in institutional protocols for atonic refractory PPH after vaginal delivery.

Maternal characteristics and causes associated with refractory postpartum haemorrhage after vaginal birth: a secondary analysis of the WHO CHAMPION trial data.

OBJECTIVE: To assess the maternal characteristics and causes associated with refractory postpartum haemorrhage (PPH). DESIGN: Secondary analysis of the WHO CHAMPION trial data. SETTING: Twenty-three hospitals in ten countries. POPULATION: Women from the CHAMPION trial who received uterotonics as first-line treatment of PPH. METHODS: We assessed the association between sociodemographic, pregnancy and childbirth factors and refractory PPH, and compared the causes of PPH between women with refractory PPH and women responsive to first-line PPH treatment. MAIN OUTCOME MEASURES: Maternal characteristics; causes of PPH. RESULTS: Women with labour induced or augmented with uterotonics (adjusted odds ratio [aOR] 1.35; 95% CI 1.07-1.72), with episiotomy or tears requiring suturing (aOR 1.82; 95% CI 1.34-2.48) and who had babies with birthweights ≥3500 g (aOR 1.33; 95% CI 1.04-1.69) showed significantly higher odds of refractory PPH compared with the reference categories in the multivariate analysis adjusted by centre and trial arm. While atony was the sole PPH cause in 53.2% (116/218) of the women in the responsive PPH group, it accounted for only 31.5% (45/143) of the causes in the refractory PPH group. Conversely, tears were the sole cause in 12.8% (28/218) and 28% (40/143) of the responsive PPH and refractory PPH groups, respectively. Placental problems were the sole cause in 11 and 5.6% in the responsive and refractory PPH groups, respectively. CONCLUSION: Women with refractory PPH showed a different pattern of maternal characteristics and PPH causes compared with those with first-line treatment responsive PPH. TWEETABLE ABSTRACT: Women with refractory postpartum haemorrhage are different from those with first-line treatment responsive PPH.

Quality of oxytocin available in low- and middle-income countries: a systematic review of the literature.

BACKGROUND: Oxytocin is the drug of choice for preventing and treating postpartum haemorrhage, an important cause of maternal death. Oxytocin is widely available in low and middle-income countries (LMIC) but there are concerns about its quality. OBJECTIVE: To identify, critically appraise and synthesise the findings of studies on the quality of oxytocin available in LMIC. SEARCH STRATEGY: We searched seven electronic databases, without language restriction. SELECTION CRITERIA: Studies reporting results of tests to assess quality of oxytocin samples from LMIC. DATA COLLECTION AND ANALYSIS: Study selection, data extraction and quality assessment were performed in duplicate. Results are presented descriptively. MAIN RESULTS: The search identified 2611 unique citations; eight studies, assessing 559 samples from 15 different countries were included. Most samples were collected from facility level settings (n = 509) and from the private sector (n = 321). The median prevalence of oxytocin samples that failed quality tests was 45.6% (range 0-80%), mostly due to insufficient amounts of active pharmacological ingredient. Over one-third of the samples (n = 204) had low (<90%) oxytocin content indicating substandard medicine; two samples had no active ingredient, suggesting possible counterfeit drugs. The proportion of low fails was higher in samples collected in Africa than in Asia or Latin America (57.5% versus 22.3% versus 0%, respectively, P < 0.0001), in private than in public sectors (34.0% versus 25.3%, P = 0.032) and in facilities than in central distributors (37.9% versus 22.0%, P = 0.030). CONCLUSION: There is a high prevalence of poor-quality oxytocin samples in LMIC countries, mainly due to inadequate amounts of active ingredient. TWEETABLE ABSTRACT: Systematic review points to problems with quality of oxytocin samples from low- and middle-income countries.

Pre-eclampsia, eclampsia and adverse maternal and perinatal outcomes: a secondary analysis of the World Health Organization Multicountry Survey on Maternal and Newborn Health.

OBJECTIVE: To assess the incidence of hypertensive disorders of pregnancy and related severe complications, identify other associated factors and compare maternal and perinatal outcomes in women with and without these conditions. DESIGN: Secondary analysis of the World Health Organization Multicountry Survey on Maternal and Newborn Health (WHOMCS) database. SETTING: Cross-sectional study implemented at 357 health facilities conducting 1000 or more deliveries annually in 29 countries from Africa, Asia, Latin America and the Middle East. POPULATION: All women suffering from any hypertensive disorder during pregnancy, the intrapartum or early postpartum period in the participating hospitals during the study period. METHODS: We calculated the proportion of the pre-specified outcomes in the study population and their distribution according to hypertensive disorders' severity. We estimated the association between them and maternal deaths, near-miss cases, and severe maternal complications using a multilevel logit model. MAIN OUTCOME MEASURES: Hypertensive disorders of pregnancy. Potentially life-threatening conditions among maternal near-miss cases, maternal deaths and cases without severe maternal outcomes. RESULTS: Overall, 8542 (2.73%) women suffered from hypertensive disorders. Incidences of pre-eclampsia, eclampsia and chronic hypertension were 2.16%, 0.28% and 0.29%, respectively. Maternal near-miss cases were eight times more frequent in women with pre-eclampsia, and increased to up to 60 times more frequent in women with eclampsia, when compared with women without these conditions. CONCLUSIONS: The analysis of this large database provides estimates of the global distribution of the incidence of hypertensive disorders of pregnancy. The information on the most frequent complications related to pre-eclampsia and eclampsia could be of interest to inform policies for health systems organisation.

Improved method robustness and ruggedness in liquid chromatography-mass spectrometry by increasing the acid content of the mobile phase.

A routine multiresidue method developed for the detection and quantification of veterinary drug residues in animal-based food was used to analyze sheep (ovine) liver. Unlike when working with previously validated matrices (e.g., bovine liver), some of the analytes of interest chromatographed in the form of split- or even fully baseline separated peaks. In other cases a significantly longer retention times (tR) was observed. A detailed investigation led to the elucidation of taurocholic acid as the causative agent. This compound is present in sheep liver at significantly higher concentrations than in most other animal tissues. Taurocholic acid is a zwitterionic compound and likely acts as an ion pairing agent, which modifies the selectivity of the stationary phase in a highly spatial and dynamic way. Injecting smaller volumes of matrix extract or the use of a significantly higher formic acid concentration in the mobile phase reduced or even completely eliminated the peak splitting. A more detailed examination led to the observation that the problem is not restricted to this particular matrix and extraction procedure or the used stationary phase. In fact, a higher formic acid concentration (e.g., 1.0 % versus 0.1 %) significantly improves the peak shape of many analytes present in fortified matrix samples as well as in pure standard solutions. In addition, analytical column aging was observed as being slower with a higher formic acid concentration. Finally the peak shape of analytes interacting with the metallic parts along the flow path of the liquid chromatograph was also significantly improved. Use of 0.1 % acid in mobile phases is often taken for granted in LC-MS. Regardless of the stationary phase, a higher ionic strength better stabilizes the pH and reduces unwanted interactions, which ultimately improves the method robustness. Flow injection experiments often show that 0.1 % acid concentrations produce the highest analyte signals. Yet, the use of 1 % acid in the mobile phase often leads to narrower and therefore taller chromatographic peaks, which may lead to lower detection limits for many analytes and to an improved separation efficiency.

A modified DRIL procedure by flow reversal of an aborted distal cephalic vein for critical hand ischaemia.

Treatment of dialysis access-related hand ischaemia with preservation of the access remains an issue. We report the case of a patient presenting critical hand ischaemia 2 years after proximalisation of a distal radio-cephalic fistula with preservation of the original access. After valvulotomy, the distal cephalic vein was used as in situ bypass and directly anastomosed to the distal brachial artery, providing a direct flow to the hand. This procedure relieved the hand ischaemia without sacrificing the functioning fistula. Six months later, the fistula and bypass were still patent, showing that flow reversal of a previous fistula can be an efficient strategy to correct dialysis access-related hand ischaemia in selected cases.

Repair of ruptured abdominal aortic aneurysm in octogenarians.

OBJECTIVE: To determine whether advanced age was independently associated with prohibitive surgical risks or impaired long-term prognosis after ruptured aortic aneurysm repair. DESIGN: Post-hoc analysis of prospective cohort. MATERIALS: Consecutive patients undergoing ruptured aneurysm repair between January 2001 and December 2010 at a tertiary referral centre. METHODS: Surgical mortality (i.e., <30 days) was compared between octogenarians and younger patients using logistic regression modelling to adjust for suspected confounders and to identify prognostic factors. Long-term survival was compared with matched national populations. RESULTS: Sixty of 248 involved patients were octogenarians (24%) and almost all were offered open repair (n = 237). Surgical mortality of octogenarians was 26.7% (adjusted odds ratio (OR) 2.1; 95% confidence interval (CI), 0.9-5.2) and confounded by cardiac disease. Hypovolaemic shock predicted perioperative death of octogenarians best (OR 5.1; 95%CI, 1.1-23.4; P = 0.037). After successful repair, annual mortality of octogenarians averaged 13.7% vs. 5.2% for younger patients. At 2 years, octogenarian survival was at 94% of the expected 'normal' survival in the general population (vs. 96% for younger patients). CONCLUSIONS: Surgical mortality of ruptured aneurysm repair was not independently related to advanced age but mainly driven by cardiac disease and manifest hypovolaemic shock. An almost normal long-term prognosis of aged patients after successful repair justifies even attempts of open repair, particularly in carefully selected patients.

[Utilization rates of lower extremity prostheses in Germany and Switzerland: A comparison of the years 2005-2008]. / Verwendungsraten von Prothesen der unteren Extremität in Deutschland und der Schweiz: Ein Vergleich der Jahre 2005-2008.

BACKGROUND: In the United States the use of total hip arthroplasty (THA) has substantially increased over the last decade. It is not known, however, if this trend can be applied to other countries as well. The aim of the current study was therefore a detailed comparison of hip, knee, and ankle arthroplasty utilization rates in Germany and Switzerland in the years 2005-2008 and a secondary comparison with the United States. PATIENTS AND METHODS: Based on datasets from the national statistical offices the number of inhabitants, gender and age distributions and the number of primary and revision surgeries were determined. These figures served for calculating primary, revision and overall surgical volumes, revision burden, primary and revision rates per 100,000 inhabitants, gender and age-specific primary and revision rates. A comparably smaller dataset was provided for the respective US analyses. RESULTS: In Germany, Switzerland and the US the number of implanted total and partial hip arthroplasties per 100,000 inhabitants rose from 235.8, 238.2 and 116.8 in 2005 to 254.7, 262.7 and 127.3 in 2008, respectively. For total and partial knee arthroplasty the rates were 156.3, 140.1 and 178.2 implantations in 2005 and 188.3, 176.8 and 213.6 in 2008, respectively. With 13.6% the revision burden in Germany was 3.6% higher than in Switzerland and accounted for 11.2% in the US. In 2008 it was 15.1% in Germany, was hence 4.6% higher than in Switzerland and remained stable at 11.2% in the US. For knee replacements the 2005 German revision burden was 11.1% which was 3.5% higher than in Switzerland and was 7.4% in the US. In 2008 it was 12.8% in Germany and 4.2% lower in Switzerland and in the US it accounted for 8.9%. In all three countries the revision burden for knee arthroplasty was constantly lower than for hip arthroplasty. CONCLUSION: In all three countries the primary rates for hip and knee replacements rose over the years but those for knee arthroplasty to a higher extent. The 2008 revision burden was highest in Germany for both types of arthroplasty. In Switzerland there was a transient revision burden decrease with a new increase from the year 2007 onwards. The US hip replacement utilization rates per 100,000 inhabitants were considerably lower than those in Germany and Switzerland and for knee replacements they were slightly higher.

Allogeneic and xenogeneic response in mixed leukocyte cultures.

The mixed lymphocyte culture (MLC) test has been regarded as an in vitro model of the recognition or sensitization phase of the homograft or graft-versus-host reaction. It has been suggested that the graft-versus-host response in vivo is less in xenogeneic combinations than in allogeneic ones and that there is a similar quantitative relationship in MLC responses. Given the above interpretation of the MLC test, this could suggest that the lesser reactivity in xenogeneic combinations may be due to a lesser recognition of the stimulus. We have done nine experiments testing allogeneic and xenogeneic combinations in MLC, largely in combinatorial fashion. The results indicate that the response in xenogeneic MLC may be as great as that in allogeneic MLC and that, as in different allogeneic mixtures, there is great variation in the extent to which xenogeneic mixtures may respond.

Interleukin 7 enhances cytolytic T lymphocyte generation and induces lymphokine-activated killer cells from human peripheral blood.

The effects of purified recombinant interleukin 7 (IL-7) on the generation of cytolytic T lymphocytes (CTL) in mixed lymphocyte culture (MLC) and on the induction of lymphokine-activated killer (LAK) cells in autologous cultures of human peripheral blood mononuclear cells were investigated. IL-7 was found to induce the generation of both CTL and LAK cells in bulk cultures. The appearance of peak CTL activity in MLC established with exogenous IL-7 was delayed in comparison with replicate cultures containing exogenous IL-2, but both cytokines stimulated quantitatively similar levels of antigen-specific lytic activity. An IL-2-neutralizing antiserum inhibited substantially, but not completely, the effect of IL-7 on CTL generation, implying the existence of both an indirect component of IL-7 activity via IL-2 utilization, as well as an IL-2-independent component. Cell surface phenotypic analysis of IL-2- or IL-7-generated CTL effector cells revealed that CD8+ cells were responsible for the vast majority of lytic activity. Limiting dilution analysis (LDA) revealed that essentially identical frequencies of CTL precursors (CTL-P) were capable of clonal expansion and/or differentiation in the presence of exogenous IL-2, IL-4, or IL-7, supporting the concept that all three of these cytokines are capable of exerting a major influence on T cell growth and differentiation. Approximately half of the CTL-P that responded in IL-7-supplemented LDA cultures did so in an IL-2-independent manner. IL-7 stimulated the development of LAK cells in autologous bulk cultures, but only weakly in comparison with IL-2. In contrast to its effects on CTL generation, the induction of LAK cells by IL-7 was virtually independent of IL-2. LAK cells induced by IL-7, like those induced by IL-2, were phenotypically heterogeneous and included CD8+, CD56+, and gamma/delta+ cells. Limiting dilution analysis indicated that IL-2 stimulated fivefold more LAK-P than IL-7 and 220-fold more than IL-4. Collectively, these data suggest that IL-7 has potent regulatory effects on human cytolytic cell populations and, either alone or in combination with other cytokines, could be important for the in vitro expansion of cells for adoptive immunotherapy.

Serologically defined and lymphocyte-defined components of the major histocompatibility complex in the mouse.

The mixed leukocyte culture (MLC) test is an in vitro model of the recognition phase of the homograft response. For the most part, activation in MLC is dependent on differences of the major histocompatibility complex (MHC). Our present studies in the mouse suggest that activation is primarily associated with differences of genetic regions of the MHC other than those which control the serologically defined (H-2) antigens. These differences do not lead to cytotoxic or agglutinating antibody formation despite extensive immunization; we have called these differences lymphocyte-defined (LD) differences. The strongest stimulation in MLC is associated with differences of the Ir region. It is possible that the Ir product is the T cell receptor and that it is this same molecule which can act as the stimulatory agent in MLC. Other possibilities are discussed.

Responsiveness of germfree mice in mixed leukocyte culture. Reexamining the nature of the responding unit.

Conventional (cv) and germfree (gf) mice are able to give a good proliferative response to allogeneic cells in the mixed leukocyte culture (MLC) test, while the response to xenogeneic stimulating cells has been in question. Previous studies by others have suggested only a low MLC response in cv animals and none in gf ones. We have found that both cv and gf animals can give a good MLC response to xenogeneic as well as allogeneic cells. These findings are of importance for our understanding of both MLC stimulation and response.

Regulation of cytolytic cell populations from human peripheral blood by B cell stimulatory factor 1 (interleukin 4).

The effects of B cell stimulatory factor 1 (BSF-1) on the generation of human CTL and lymphokine-activated killer (LAK) cells in vitro were investigated. Both L-2 and BSF-1 were potent helper factors for the generation of antigen-specific CTL in MLC; detection of optimal BSF-1-induced CTL activity in this system occurred when BSF-1 was added to cultures after an initial period of activation during which exogenous BSF-1 was not present. In contrast to IL-2, BSF-1 failed to induce an LAK cell population, as detected with Daudi tumor targets, in cultures that had not been allosensitized. Furthermore, when both lymphokines were added together at culture initiation, BSF-1 inhibited the IL-2-driven generation of cytolytic cells. The differential ability of BSF-1 to promote the generation of CTL but not LAK could have important implications for lymphokine-mediated immunotherapy.

Human interleukin 4 receptor confers biological responsiveness and defines a novel receptor superfamily.

IL-4, a pleiotropic cytokine produced by T lymphocytes, plays an important role in immune responsiveness by regulating proliferation and differentiation of a variety of lymphoid and myeloid cells via binding to high affinity receptors. In this report we describe the isolation and functional expression of a human IL-4-R cDNA. When transfected into COS-7 cells, the cDNA encodes a 140-kD cell-surface protein. After transfection into a murine T cell line, the cDNA encodes a protein that binds human IL-4 with high affinity and can confer responsiveness to human IL-4. The predicted extracellular domain of the IL-4-R exhibits significant amino acid sequence homology with the beta subunit of the IL-2-R (p75), and the receptors for IL-6, erythropoietin, and prolactin. These receptors comprise a novel superfamily with extracellular domains characterized by four conserved cysteine residues and a double tryptophan-serine (WSXWS) motif located proximal to the transmembrane region.

Post-interface signal suppression, a phenomenon observed in a single-stage Orbitrap mass spectrometer coupled to an electrospray interfaced liquid chromatograph.

Signal suppression is a common issue when analyzing compounds by liquid chromatography coupled to mass spectrometry (LC/MS/MS). Suppression of signals is caused by co-eluting matrix compounds and is thought to take place in the interface. This paper reports strong signal suppression effects which were observed when using a single-stage Orbitrap instrument which was coupled by an electrospray interface to a liquid chromatograph. This type of signal suppression (often the complete loss of certain analyte signal) is observed in addition to signal suppression originating in the electrospray interface. The location of where this phenomenon occurs was shown to be clearly beyond the interface region. It was suspected that not the Orbitrap cell itself, but the C-trap, which is an integral part within the Orbitrap instrument, was the probable location. Such post-interface signal suppression was observed--and could be experimentally induced--when multiply charged ions (e.g. electrospray protonated proteins) were co-eluting with the analytes. High concentrations of proteins, yet not exceeding the maximum ion capacity of the trap, can cause a complete loss of all low m/z masses. This paper describes the practical implication when analyzing heavy matrix samples and discusses strategies to reduce such detrimental effects.

Prevention of rupture of abdominal aortic aneurysm.

BACKGROUND AND AIMS: Two thirds of patients with an abdominal aortic aneurysm (AAA) have relevant coronary artery disease (CAD). AAAs are prevalent in up to 16% of smokers with CAD. General screening of AAA is controversial. Aim was to assess the potential of finding AAA prior to rupture among patients with known CAD. Main endpoint was whether AAA could have been found during follow-up by sonography or at other time of cardiovascular evaluation. MATERIAL AND METHODS: Retrospective study. 213 consecutive, formerly unknown emergently operated AAAs, treated emergently for symptoms (n = 91) or rupture (n = 122) (rAAA) between January 1998 and June 2005. Patient charts were analysed and primary care physicians contacted. RESULTS: At presentation, mean age was 71 (+/-9) years, twenty (9%) were female. AAA had a mean diameter of 7.6 cm. Two thirds (143) were clinically obese (BMI 27 +/-5). 137 (64%) were active smokers, 32 (15%) had diabetes, 151 (71%) were hypertensive, and 80 (38%) received statin treatment. CAD had been diagnosed in 95 (45%) 9 years earlier and followed up. Thirty-five (16%) had had myocardial infarction. Echocardiography had been performed in 52 (24%). Thirty day mortality after open surgery was 25 (21%). CONCLUSION: All patients with rAAA had been seen by a GP or cardiologist within a year prior to presentation. The cost effectiveness of selective AAA screening should be evaluated in a larger study.

Determinants of haemodialysis access survival.

BACKGROUND: Vascular access patency is of vital importance for patients requiring haemodialysis. This analysis validates potential risk factors and benefits in patients undergoing vascular access procedures. PATIENTS AND METHODS: Vascular access procedures performed over a two-year period were retrospectively analysed. Clinical data and concomitant medication were retrieved from files as were surgical data following a standardized data capture sheet. Outcome parameters were primary (PP) and secondary patency (SP) as well as freedom from repeated revascularization. Minimal follow-up with functioning access was 679 days. RESULTS: During the observation period, 244 patients (mean age 62.2 +/- 0.9 years, 60.7 % male patients, 36.1 % pre-emptive, 31.1 % late referral) underwent vascular accesses procedures. PP and SP were 35.6 % and 45.6 %, respectively, at 540 days. Presence of diabetes mellitus was associated with decreased PP (OR: 0.6, 95 %-CI: 0.3 - 1.0) and SP (OR: 0.4, 95 %-CI: 0.2 - 0.7), whereas female gender was associated with lower SP (OR: 0.6, 95 %-CI: 0.3 - 0.9) and freedom from repeated revascularization rates (OR: 0.6, 95 %-CI: 0.3 - 1.0). In contrast, presence of hyperparathyreoidism was associated with higher SP (OR: 1.7, 95 %-CI: 1.0 - 3.0) and freedom from repeated revascularization (OR: 1.7, 95 %-CI: 1.0 - 3.0) rates. CONCLUSIONS: Haemodialysis access performs worst in patients with diabetes mellitus and in women. The benefit of hyperparathyroidism should be interpreted as hypothesis generating.

Optimized multimatrix calibration concept for liquid chromatography mass spectrometry-based bioanalysis methods.

In this paper, a calibration procedure for LC/MS-based bioanalysis methods, termed "A/B fortification", is proposed. The concept relies on the post-extraction fortification (B-spike) of an aliquot of the injection-ready sample extract for the determination and compensation of specific signal suppression or enhancement effects compared to matrix-free extract prepared in buffer or mobile phase. Conventional analyte recovery, observed due to the incomplete extraction of analytes from the sample or losses during a cleanup, is determined by the conventional pre-extraction fortification (A-spike) of a blank sample that belongs to the same type of matrix as the sample with the unknown analyte concentration. This approach permits a higher throughput than conventional sample fortification strategies. The results obtained by utilizing the A/B fortification concept were extensively compared against conventional methods (representative bank matrix fortification, sample fortification and internal standard). The proposed concept (based on the pre-fortification of a reference matrix and post-fortification of the sample) was found to be significantly less biased than internal standard-based techniques. The A/B fortification indicated a better accuracy than the sample fortification or representative blank matrix fortification approach and, most importantly, produced significantly fewer outliers. This was linked to the fact that in the case of the A/B fortification, the uncertainty of the subtraction of two peak areas (fortified minus unfortified sample) is reduced, because fortifications are not made prior to the extraction step but are made into the final injection-ready sample extract. Fortification into an injection-ready aliquot eliminates all sample processing-related differences (procedural errors), which can affect conventional sample fortification-based quantifications.

Does the ion mobility resolving power as provided by commercially available ion mobility quadrupole time-of-flight mass spectrometry instruments permit the unambiguous identification of small molecules in complex matrices?

Quadrupole based mass spectrometry based detection has experienced enormous improvements in terms of sensitivity over the last centuries. This development has not been equally matched with improvements in selectivity. Hence, the use of unit mass based MS/MS transitions or high resolution (HRMS) based extracted ion chromatograms is gradually becoming insufficient in the field of high sensitivity multi-residue analysis (e.g. pesticides in food). As a consequence, commercial instruments hyphenating ion mobility (IMS) with low or high resolution mass spectrometry based detection have appeared. The use of such an additional (frequently claimed to be orthogonal) dimension is intended to increase selectivity. In addition, IMS derived collision cross section (CCS) has been proposed to be used as an additional identification point for the unambiguous identification of trace compounds in complex matrices. It is the topic of this paper to investigate the benefit of using such a hyphenated technique for trace analysis of small molecules in complex matrices. The potential of CCS to serve as additional identification point has been critically evaluated. Discussed are the effect of CCS data on false detects and missing detects of analytes present at trace levels. This involves the investigation of the physical resolving power provided by HRMS, IMS and chromatography as well as the correlation among these parameters (orthogonality). It is the conclusion that currently commercially available travelling wave and linear drift tube based IMS devices with a resolving power of up to 50 permit a reduction of false detects, yet this comes at the price of a higher likelihood of missing detects. The reduction of missing detects and the use of CCS as potential confirmatory information would require IMS resolving powers above 100.