Risk factors for recurrence of post-dural puncture headache following an epidural blood patch: a retrospective cohort study.

INTRODUCTION: Post-dural puncture headache (PDPH) occurs in 0.38-6.3% of neuraxial procedures in obstetrics. Epidural blood patch (EBP) is the standard treatment but fails to provide full symptom relief in 4-29% of cases. Knowledge of the risk factors for EBP failure is limited and controversial. This study aimed to identify these risk factors. METHODS: We performed a retrospective cohort study using electronic records of 47920 patients who underwent a neuraxial procedure between 2001 and 2018 in a large maternity hospital in Switzerland. The absence of full symptom relief and the need for further treatment was defined as an EBP failure. We performed univariate and multivariate analyses to compare patients with a successful or failed EBP. RESULTS: We identified 212 patients requiring an EBP. Of these, 55 (25.9%) had a failed EBP. Signs and symptoms of PDPH did not differ between groups. While needle size and multiple pregnancies were risk factors in the univariate analysis, mostly those related to the performance of the EBP remained significant following adjustment. The risk of failure increased when the epidural space was deeper than 5.5 cm (OR 3.08, 95% CI 1.26 to 7.49) and decreased when the time interval between the initial dural puncture and the EBP was >48 h (OR 0.20, 95% CI 0.05 to 0.83). CONCLUSION: Persistence of PDPH following a first EBP is not unusual. Close attention should be given to patients having their EBP performed <48 h following injury and having an epidural space located >5.5 cm depth, as these factors are associated with a failed EBP.

Data-driven nonlinear model reduction to spectral submanifolds in mechanical systems.

While data-driven model reduction techniques are well-established for linearizable mechanical systems, general approaches to reducing nonlinearizable systems with multiple coexisting steady states have been unavailable. In this paper, we review such a data-driven nonlinear model reduction methodology based on spectral submanifolds. As input, this approach takes observations of unforced nonlinear oscillations to construct normal forms of the dynamics reduced to very low-dimensional invariant manifolds. These normal forms capture amplitude-dependent properties and are accurate enough to provide predictions for nonlinearizable system response under the additions of external forcing. We illustrate these results on examples from structural vibrations, featuring both synthetic and experimental data. This article is part of the theme issue 'Data-driven prediction in dynamical systems'.

Adverse side effects and route of administration of opioids in combined spinal-epidural analgesia for labour: a meta-analysis of randomised trials.

BACKGROUND: Studies report an increased risk of maternal and fetal adverse side effects when combined spinal-epidural, rather than standard epidural, analgesia is provided for labour and delivery. Intrathecal opioids used with local anaesthetic in combined spinal-epidural analgesia may be a cause. It is not known whether this is due to the addition of opioid to local anaesthetic in the intrathecal space only or due to concomitant administration into the intrathecal and epidural spaces. METHODS: We searched for randomised trials comparing maternal, obstetrical and neonatal outcomes in parturients having combined spinal-epidural or standard epidural analgesia, and compared subgroups of patients according to the route of administration of opioids in combined spinal-epidural techniques. Studies were evaluated for eligibility and quality. Fixed and random-effects models were used for pooled data analysis and outcomes were compared using relative risk (RR) or mean difference with 95% confidence intervals (CI). RESULTS: We identified 1658 reports and 41 fully published randomised controlled trials. In patients who received combined spinal-epidural techniques, an increased risk of nausea/vomiting (RR 1.31, CI 1.0 to 1.72), pruritus (RR 4.26, CI 2.59 to 7.0) and fetal bradycardia (RR 2.38, CI 1.57 to 3.62) was observed regardless of the route of administration. In contrast, hypotension occurred more frequently after combined intrathecal and epidural opioid (RR 1.54, 1.22 to 1.93; P-value 0.02 for subgroup difference). CONCLUSION: For combined spinal-epidural techniques, the administration of opioids in combination with local anaesthetic, particularly when used in both the intrathecal and epidural space, should be carefully considered.

Coherent Lagrangian swirls among submesoscale motions.

The emergence of coherent Lagrangian swirls (CLSs) among submesoscale motions in the ocean is illustrated. This is done by applying recent nonlinear dynamics tools for Lagrangian coherence detection on a surface flow realization produced by a data-assimilative submesoscale-permitting ocean general circulation model simulation of the Gulf of Mexico. Both mesoscale and submesoscale CLSs are extracted. These extractions prove the relevance of coherent Lagrangian eddies detected in satellite-altimetry-based geostrophic flow data for the arguably more realistic ageostrophic multiscale flow.

Risk factors for post-dural puncture headache following injury of the dural membrane: a root-cause analysis and nested case-control study.

BACKGROUND: Post-dural puncture headache following trauma to the dural membrane during neuraxial anaesthesia occurs in 0.13-6.5% of pregnant patients. Identifying factors beyond individual performance that contribute to this adverse event is crucial to developing improvement strategies. METHODS: We used a root cause analysis framework, in a nested case-control study, to identify associated factors. Cases were all patients who had a post-dural puncture headache requiring an epidural blood patch. These patients were matched to a random group of control patients without post-dural puncture headache or known dural injury. Mixed logistic modelling was used. RESULTS: Within a dataset of 35 763 patients, we selected all 154 patients with post-dural puncture headache and compared them with 616 controls. Migraine (odds ratio [OR] 10.60, 95% CI 2.74 to 41.05), obstetric and perinatal pathology (OR 10.85, 95% CI 4.29 to 21.42), and multiple insertion attempts (OR 11.48, 95% CI 6.29 to 20.94), increased the risk of post-dural puncture headache. In contrast, training >3 years (OR 0.20, 95% CI 0.55 to 0.76) and a nurse anaesthetist present during the procedure (OR 0.05, 95% CI 0.01 to 0.29) decreased the risk. The anaesthetist's identity, the size of the labour room, the timing of the procedure or workload did not modify the risk. CONCLUSION: Post-dural puncture headache in this setting is not the result of the individual anaesthetist's characteristics alone. Additional factors including team composition, the presence of obstetrical perinatal pathology, and associated patient's conditions, are also associated with this event. Improvement strategies should consider all these factors.

Perioperative structure and process quality and safety indicators: a systematic review.

BACKGROUND: Clinical indicators assess healthcare structures, processes, and outcomes. While used widely, the exact number and level of scientific evidence of these indicators remains unclear. The aim of this study was to evaluate the number, type, and evidence base of clinical process and structure indicators currently available for quality and safety measurement in perioperative care. METHODS: We performed a systematic review searching Medline, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane, Google Scholar, and System for Information in Grey Literature in Europe databases for English language human studies in adults (age >18) published in the past 10 years (January 2005-January 2016). We also included professional and governmental body publications and guidelines describing the development, validation, and use of structure and process indicators in perioperative care. RESULTS: We identified 43 860 journal articles and 43 relevant indicator program publications. From these, we identified a total of 1282 clinical indicators, split into structure (36%, n=463) and process indicators (64%, n=819). The dimensions of quality most frequently addressed were effectiveness (38%, n=475) and patient safety (29%, n=363). The majority of indicators (53%, n=675) did not have a level of evidence ascribed in their literature. Patient-centred metrics accounted for the fewest published clinical indicators. CONCLUSIONS: Despite widespread use, the majority of clinical indicators are not based on a strong level of scientific evidence. There may be scope in setting standards for the development and validation process of clinical indicators. Most indicators focus on the effectiveness, safety, and efficiency of care. PROSPERO DATABASE: CRD4201501277.

Intrathecal clonidine as an adjuvant for neuraxial anaesthesia during caesarean delivery: a systematic review and meta-analysis of randomised trials.

BACKGROUND: Clonidine is used as adjuvant to local anaesthetics for spinal anaesthesia. Its potential harm and benefits have not been systematically reviewed in obstetrics, and medical regulatory authorities do not recommend its intrathecal administration. The aim of this study was to assess the safety and efficacy of intrathecal clonidine for caesarean delivery. METHODS: We conducted a systematic literature search in Medline, Embase, the Cochrane Library databases and trial registries for randomised trials assessing intrathecal clonidine as an adjuvant to local anaesthetics in patients undergoing caesarean delivery. Studies were assessed for quality, and data were extracted on study characteristics, safety and efficacy. Pooled data analysis using random-effects models was performed. Relative risk (RR) or mean difference with 95% confidence intervals (CI) were used to analyse outcomes. RESULTS: Of 201 reports screened, 12 relevant clinical trials were included. Clonidine prolonged the duration of sensory block by 128.2min (95% CI 81.7 to 174.8) and motor block by 44.7min (95% CI 8.7 to 80.7). Clonidine increased sedation, RR 3.92 (95% CI 1.17 to 13.14), but did not increase the risk of hypotension, pruritus or postoperative nausea and vomiting. Apgar scores at 1 or 5min were not influenced by the addition of intrathecal clonidine. CONCLUSION: Clonidine is an effective and safe adjuvant to local anaesthetics for spinal anaesthesia for caesarean delivery. This opens the debate as to whether intrathecal clonidine as an "off label" prescription should be reconsidered by medical regulatory authorities.

Risk factors for peripheral nerve injuries following neuraxial labour analgesia: a nested case-control study.

BACKGROUND: Post-partum lower extremity motor and sensory dysfunctions occur in 0.1-9.2‰ of deliveries. While macrosomia, lithotomy position and forceps use are well-identified causes of peripheral nerve injuries, additional contributors such as patient condition and anaesthesia care may also have to be considered. METHODS: We performed a case-control study nested in a cohort of 19,840 patients having neuraxial anaesthesia for childbirth. Cases were all patients who developed motor or sensory dysfunction of lower extremities in the post-partum period. These were compared, using Chi-square, Fisher's exact test, logistic regression and time series, to a random sample of controls without any neurological symptoms or injury. RESULTS: We identified 19 (0.96‰) patients with peripheral nerve injuries of which 15 (0.76‰) were likely associated with obstetrical care. In four additional cases (0.20‰), a nerve root injury due to the Tuohy needle was suspected. Univariate risk factors were: a gestational age ≥ 41 weeks, Odds Ratio (OR) 3.8; 95% CI: 1.1-13.1, late initiation of neuraxial anaesthesia OR 8.2; 95% CI: 1.8-37.9, a repeated anaesthetic procedure OR 2.8; 95% CI: 1.0-7.8, assisted delivery with forceps OR 9.8; 95% CI: 1.2-114.1 and newborn birth weight > 3.5 kg with an OR 6.8; 95% CI: 2.0-22.5. CONCLUSION: Obstetrical related factors are the most prominent risk associated with peripheral nerve injuries. This study highlights however that patient and anaesthesia-related factors may also contribute to peripheral nerve injuries.

Post-traumatic stress disorder in parturients delivering by caesarean section and the implication of anaesthesia: a prospective cohort study.

BACKGROUND: Post-traumatic stress disorder (PTSD) occurs in 1-7% of women following childbirth. While having a caesarean section (C-section) is known to be a significant risk factor for postpartum PTSD, it is currently unknown whether coexisting anaesthesia-related factors are also associated to the disorder. The aim of this study was to assess anaesthesia-linked factors in the development of acute postpartum PTSD. METHODS: We performed a prospective cohort study on women having a C-section in a tertiary hospital in Switzerland. Patients were followed up six weeks postpartum. Patient and procedure characteristics, past morbidity or traumatic events, psychosocial status and stressful perinatal events were measured. Outcome was divided into two categories: full PTSD disease and PTSD profile. This was based on the number of DSM-IV criteria of the Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM-IV) present. The PTSD Checklist Scale and the Clinician Administered PTSD Scale were used for measurement. RESULTS: Of the 280 patients included, 217 (77.5%) answered the questionnaires and 175 (62.5%) answered to an additional phone interview. Twenty (9.2%) had a PTSD profile and six (2.7%) a PTSD. When a full predictive model of risk factors for PTSD profile was built using logistic regression, maternal prepartum and intrapartum complications, anaesthetic complications and dissociative experiences during C-section were found to be the significant predictors for PTSD profile. CONCLUSION: This is the first study to show in parturients having a C-section that an anaesthesia complication is an independent risk factor for postpartum PTSD and PTSD profile development, in addition to known perinatal and maternal risk factors.

Meta-analysis of two-arm studies: Modeling the intervention effect from survival probabilities.

Pooling the hazard ratios is not always feasible in meta-analyses of two-arm survival studies, because the measure of the intervention effect is not systematically reported. An alternative approach proposed by Moodie et al. is to use the survival probabilities of the included studies, all collected at a single point in time: the intervention effect is then summarised as the pooled ratio of the logarithm of survival probabilities (which is an estimator of the hazard ratios when hazards are proportional). In this article, we propose a generalization of this method. By using survival probabilities at several points in time, this generalization allows a flexible modeling of the intervention over time. The method is applicable to partially proportional hazards models, with the advantage of not requiring the specification of the baseline survival. As in Moodie et al.'s method, the study-level factors modifying the survival functions can be ignored as long as they do not modify the intervention effect. The procedures of estimation are presented for fixed and random effects models. Two illustrative examples are presented.

Quantitative flow analysis of swimming dynamics with coherent Lagrangian vortices.

Undulatory swimmers flex their bodies to displace water, and in turn, the flow feeds back into the dynamics of the swimmer. At moderate Reynolds number, the resulting flow structures are characterized by unsteady separation and alternating vortices in the wake. We use the flow field from simulations of a two-dimensional, incompressible viscous flow of an undulatory, self-propelled swimmer and detect the coherent Lagrangian vortices in the wake to dissect the driving momentum transfer mechanisms. The detected material vortex boundary encloses a Lagrangian control volume that serves to track back the vortex fluid and record its circulation and momentum history. We consider two swimming modes: the C-start escape and steady anguilliform swimming. The backward advection of the coherent Lagrangian vortices elucidates the geometry of the vorticity field and allows for monitoring the gain and decay of circulation and momentum transfer in the flow field. For steady swimming, momentum oscillations of the fish can largely be attributed to the momentum exchange with the vortex fluid. For the C-start, an additionally defined jet fluid region turns out to balance the high momentum change of the fish during the rapid start.

Atypical headache following dural puncture in obstetrics.

BACKGROUND: In obstetrics, post-dural puncture headache is a well-recognised complication. Typical symptoms include fronto-temporal or occipital headache, worsening with ambulation and improving in the decubitus position. Occasionally, patients present with non-postural headache, although relatively little is known about this atypical presentation. The purpose of this study was to determine the incidence, associated signs and risk factors for this atypical manifestation of post-dural puncture headache. METHODS: We analysed a series of 27 064 parturients having a neuraxial procedure between January 2001 and December 2010. Using data from electronic anaesthesia patient records, medical charts and a postpartum quality audit, we identified all parturients with atypical post-dural puncture headache. We assessed the incidence and used uni- and multivariate analysis to identify associated risk factors. RESULTS: Amongst 142 parturients with post-dural puncture headache, eight (5.6%, 95% CI 1.7-9.4%) had atypical non-postural headache. Associated symptoms were stiffness and pain in the cervical, thoracic or lumbar vertebral area, visual disturbances and vertigo. Significant risk factors for developing atypical signs were previous migraine, odds ratio 6.1 (95% CI 1.2-28.7), a more cephalad level of needle insertion, odds ratio 17.2 (95% CI 1.4-210.1) and identification of dural puncture by aspiration of cerebrospinal fluid from the epidural catheter, odds ratio 5.5 (95% CI 1.2-24.4). Following multivariate analysis, recognition of dural puncture by aspiration of cerebrospinal fluid from the epidural catheter was the most significant predictor of non-orthostatic postdural puncture headache. CONCLUSION: Anaesthetists should be aware of this atypical clinical presentation, particularly if there is a past history of migraine, a more cephalad level of needle insertion or identification of dural puncture by aspiration of cerebrospinal fluid from the epidural catheter.

[Quality improvement initiatives in hospitals: which one to choose]. / Démarches qualité à l'hôpital: laquelle choisir?

The number of quality improvement initiatives in hospitals has been steadily increasing in the last decades. Most of these initiatives are inspired by three quality control and improvement models developed in the manufacturing industry: the final inspection, the quality assurance and the total quality management. The purpose of this review is to describe how these methods have been implemented in healthcare organizations and to assess their effectiveness and acceptability by healthcare professionals. This review should help quality managers and healthcare professionals to choose a model that is best adapted to their needs and expected goals.

Observation of two-neutrino double-beta decay in 136Xe with the EXO-200 detector.

We report the observation of two-neutrino double-beta decay in (136)Xe with T(1/2) = 2.11 ± 0.04(stat) ± 0.21(syst) × 10(21) yr. This second-order process, predicted by the standard model, has been observed for several nuclei but not for (136)Xe. The observed decay rate provides new input to matrix element calculations and to the search for the more interesting neutrinoless double-beta decay, the most sensitive probe for the existence of Majorana particles and the measurement of the neutrino mass scale.

[Undesirable events during the perioperative period and communication deficiencies]. / Évènements indésirables et problèmes de communication en périopératoire.

In recent decades, anaesthesia and surgery have undergone major scientific and technical developments. However, these improvements have not solved a recurring problem, communication deficiencies within teams in charge of surgical patients. Current figures show that 21% to 65% of accidents and errors in patient management during the perioperative period are related to communication problems. These problems occur when gaps arise in the continuity and coordination of care within teams. Some of the contributing factors to these gaps are emergency status of patients, staff shifts and handovers following patient transfers. To minimize the impact of these phenomena, it is important to improve standardization of information flow within operating theatres and to improve teamwork between anaesthetists and surgeons. This can be done through crew resource management training programs or simulation. This should ultimately contribute to minimise medical error and improve the overall quality of care provided to patients in operating theatres and during all the perioperative period.