Emergencies in obstetric anaesthesia: a narrative review.

We conducted a narrative review in six areas of obstetric emergencies: category-1 caesarean section; difficult and failed airway; massive obstetric haemorrhage; hypertensive crisis; emergencies related to neuraxial anaesthesia; and maternal cardiac arrest. These areas represent significant research published within the last five years, with emphasis on large multicentre randomised trials, national or international practice guidelines and recommendations from major professional societies. Key topics discussed: prevention and management of failed neuraxial technique; role of high-flow nasal oxygenation and choice of neuromuscular drug in obstetric patients; prevention of accidental awareness during general anaesthesia; management of the difficult and failed obstetric airway; current perspectives on the use of tranexamic acid, fibrinogen concentrate and cell salvage; guidance on neuraxial placement in a thrombocytopenic obstetric patient; management of neuraxial drug errors, local anaesthetic systemic toxicity and unusually prolonged neuraxial block regression; and extracorporeal membrane oxygenation use in maternal cardiac arrest.

Fructose Metabolism and Cardiac Metabolic Stress.

Cardiovascular disease is one of the leading causes of mortality in diabetes. High fructose consumption has been linked with the development of diabetes and cardiovascular disease. Serum and cardiac tissue fructose levels are elevated in diabetic patients, and cardiac production of fructose via the intracellular polyol pathway is upregulated. The question of whether direct myocardial fructose exposure and upregulated fructose metabolism have potential to induce cardiac fructose toxicity in metabolic stress settings arises. Unlike tightly-regulated glucose metabolism, fructose bypasses the rate-limiting glycolytic enzyme, phosphofructokinase, and proceeds through glycolysis in an unregulated manner. In vivo rodent studies have shown that high dietary fructose induces cardiac metabolic stress and functional disturbance. In vitro, studies have demonstrated that cardiomyocytes cultured in high fructose exhibit lipid accumulation, inflammation, hypertrophy and low viability. Intracellular fructose mediates post-translational modification of proteins, and this activity provides an important mechanistic pathway for fructose-related cardiomyocyte signaling and functional effect. Additionally, fructose has been shown to provide a fuel source for the stressed myocardium. Elucidating the mechanisms of fructose toxicity in the heart may have important implications for understanding cardiac pathology in metabolic stress settings.

A review of the Turned-down Onto Pericapsular-tissue Hemisectioned Amputated Toe (TOPHAT) flap for wound coverage during ray amputations of the toes.

INTRODUCTION: Exposure of the adjacent Metatarsal-Phalangeal Joint (MTPJ) commonly occurs after application of Topical Negative Pressure Wound Therapy (TNPWT) for a ray amputation wound. This is due to mechanical soft tissue erosion or trauma to the adjacent digital artery from direct pressure effect. This results in toe gangrene requiring a ray amputation and ultimately a larger wound bed. We describe the use of the Turned-down Onto Pericapsular-tissue Hemisectioned Amputated Toe (TOPHAT) flap - a filleted toe flap to protect the adjacent MTPJ capsule combined with a novel Negative Pressure Wound Therapy with instillation and dwell-time (NPWTi-d) dressing technique. The flap protects the adjacent joint capsule and reduces the wound burden whilst allowing the wound to benefit from TNPWT, thereby accelerating wound healing. MATERIAL AND METHODS: A retrospective review was conducted of patients with toe gangrene requiring ray amputation that underwent the TOPHAT flap on in our institution from 2019 and 2020. Complications such as wound dehiscence, hematoma, flap necrosis and secondary infection were recorded. Other outcomes recorded were time taken to final skin grafting and time taken for complete wound epithelialization. RESULTS: 9 patients underwent treatment with the TOPHAT flap. 2 patients had flap necrosis. 7 patients progressed to definitive skin coverage with skin grafting. One patient subsequently had progressive arterial disease despite successful skin grafting and required above knee amputation. The mean time to final skin grafting and complete wound epithelialization was 49.5 days and 107.5 days respectively. All patients were satisfied with the outcomes and were able to return to their pre-morbid function. CONCLUSIONS: The TOPHAT flap has a consistent vascular supply that provides durable soft tissue coverage. It is a robust and easily reproducible technique to accelerate wound healing after ray amputations even in patients with peripheral vascular disease.

Impact of adherence goal awareness intervention on PDC in various settings: Does awareness help modify medication-taking behavior?

Background: Interventions to improve medication adherence in chronic conditions have shown limited success or sustainability. Previous data revealed that phone calls to patients regarding adherence goal awareness resulted in significant improvement in proportion of days covered (PDC). Objectives: The objective of this study was to explore specific pharmacist adherence interventions via phone in various practice settings. Methods: A prospective, randomized controlled study was conducted with patients who belonged to university-associated health care settings [ambulatory care, chain store, small health plan, and federally qualified health center (FQHC)]. At each site, patients with at least one chronic medication and a calculated PDC < 0.80 were randomized into control (n=115) and intervention (n=126) groups. Control groups (C) received usual pharmacy communication while intervention groups (X) were specifically called by a pharmacist to be informed of PDC goals and their commitment to adherence. PDC values were calculated 3 to 12 months for both groups the time of intervention, then compared with each patient's respective baseline/pre-PDC. Results: Data from a total of 241 patients were pooled to examine change in PDC. There was no significant difference between groups in baseline criteria or PDC. Comparing within groups, there were significant correlations between Pre- and Post-PDCs for the intervention group (X = 0.32 p < 0.05) alone. There were significant improvements from initial PDC to those calculated at the time of Post-intervention PDC within both groups, (C = 0.18 ± 0.28 p < 0.05) and (X = 0.16 ± 0.24, p < 0.05). Approximately 44% of all sampled patients reached their adherence goals (PDC ≥ 0.80) after 3-9 months. Conclusions: Results suggested that patient adherence behavior may improve after any call made by pharmacy staff. This communication and attention from the pharmacy may be enough for patients to consider their medication-taking habits without the need for discussing specific goals and importance of adherence.

The incidence of dry chlorhexidine gluconate transfer from skin to surgical gloves: a simulation and in vitro study.

BACKGROUND: To prevent alcohol-based chlorhexidine from reaching the cerebrospinal fluid, it is recommended that the antiseptic solution be allowed to dry before skin palpation or puncture. However, no guidelines specify a drying time interval. Manufacturers recommend 3 min of air drying, based upon the isopropyl alcohol component. Therefore, to fill this knowledge gap, we designed a simulation study to investigate the incidence of primary chlorhexidine transfer from skin to gloves following three drying time intervals. We also investigated the incidence of secondary chlorhexidine transfer from gloves to another surface following one drying time interval. METHODS: An alcohol-based chlorhexidine antiseptic solution with dye, ChloraPrep®, was applied to the skin of the lumbar region of 20 volunteers. Cotton-tipped applicators wrapped in material from gloves were taken from the application area at 3, 4, 5, and 10 min following application. Transfer of chlorhexidine from skin to gloves, and gloves to another medium, was assessed through a chemical assay that produced a color change when chlorhexidine was present on the sample. RESULTS: The incidence of primary chlorhexidine transfer from skin to gloves at 3, 4 and 10 min following application was 99.5%, 99.4%, and 99.6%, respectively. The incidence of secondary chlorhexidine transfer from gloves to another surface was 68.9%. CONCLUSION: Gloves are routinely contaminated with chlorhexidine during central neuraxial blockade. The high incidence of secondary transfer in our simulation suggests a pathway by which chlorhexidine may gain access to the neuraxial space.

Peripartum management of a parturient with type 1C (clearance) von Willebrand disease.

Peripartum replacement of factor VIII and von Willebrand factor is not usually required in type 1 von Willebrand disease, as the levels of endogenous factors tend to increase to within the normal range as a physiological change of pregnancy. However, there is wide heterogeneity of genotypes and phenotypes associated with type 1 von Willebrand disease. Here, we describe the anesthetic management of a parturient with type 1C von Willebrand disease, a subtype characterized by decreased plasma von Willebrand factor survival.

Determining the effective pre-oxygenation interval in obstetric patients using high-flow nasal oxygen and standard flow rate facemask: a biased-coin up-down sequential allocation trial.

Using biased-coin sequential allocation, we sought to determine the effective time interval in 90% of healthy parturients to achieve a target endpoint end-tidal oxygen of ≥ 90% using standard flow rate facemask and high-flow nasal oxygen. Eighty healthy parturients were randomly assigned to standard facemask (n = 40) or high-flow nasal oxygen (n = 40) groups; half of the parturients in the high-flow nasal oxygen group also used a simple no-flow facemask to minimise air entrainment. The effective time interval for 90% of parturients to achieve the target endpoint for standard facemask was 3.6 min (95%CI 3.3-6.7 min), but could not be estimated for the high-flow nasal oxygen groups with or without an additional simple facemask, as eight minutes was insufficient to achieve the target endpoint for 55% and 92% of parturients, respectively. Furthermore, after three minutes, the target endpoint was reached by 71% in the standard facemask group vs. 0% in the high-flow nasal oxygen groups. After four minutes, the target endpoint was reached by 100% in the standard facemask, 80% in the high-flow nasal oxygen with simple facemask and 67% in the high-flow nasal oxygen groups. Beyond four minutes, there was no improvement in pre-oxygenation success using high-flow nasal oxygen. In conclusion, under the conditions of our study, the effective time interval for 90% of parturients to achieve an end-tidal oxygen ≥ 90% for standard flow rate facemask was estimated to be 3.6 min, but could not be estimated for high-flow nasal oxygen groups even after eight minutes.

High-flow nasal oxygen vs. standard flow-rate facemask pre-oxygenation in pregnant patients: a randomised physiological study.

High-flow nasal oxygen has been shown to provide effective pre-oxygenation and prolong apnoeic time during intubation attempts in non-pregnant patients. We aimed to compare pre-oxygenation using high-flow nasal oxygen (30-70 l.min-1 oxygen flow) via nasal prongs with standard 15 l.min-1 oxygen breathing via a tight-fitting facemask. Forty healthy parturients were randomly allocated to these two groups, and furthermore each patient underwent the selected pre-oxygenation method with both 3-min tidal volume breathing and 30s tidal breathing followed by eight vital capacity breaths. With 3-min tidal volume breathing, the respective estimated marginal means for high-flow nasal oxygen and standard flow rate facemask pre-oxygenation were 87.4% (95%CI 85.5-89.2%) and 91.0% (95%CI 89.3-92.7%), p = 0.02; with eight vital capacity breaths the estimated marginal means were 85.9% (95%CI 84.1-87.7%) and 91.8% (95%CI 90.1-93.4%, p < 0.0001). Furthermore, high-flow nasal oxygen did not reliably achieve a mean end-tidal oxygen concentration ≥ 90% compared with the standard flow rate facemask. In this physiological study, high-flow nasal oxygen pre-oxygenation performed worse than standard flow rate facemask pre-oxygenation in healthy term parturients.

Sepsis in pregnancy and the puerperium.

Sepsis remains a leading cause of maternal morbidity and mortality. Recognition and treatment of maternal sepsis are often delayed due to the physiological adaptations of pregnancy and vague or absent signs and symptoms during its initial presentation. Over the past decade, our understanding of sepsis has evolved and maternal early warning systems have been developed in an effort to help providers promptly identify and stratify parturients who are at risk. In addition, new consensus definitions and care bundles have recently been published by the World Health Organization and the Surviving Sepsis Campaign to facilitate earlier recognition and timely management of sepsis. In this narrative review, we summarize the available evidence about sepsis and provide an overview of the research efforts focused on maternal sepsis to date. Controversies and challenges surrounding the anesthetic management of parturients with sepsis or at risk of developing sepsis during pregnancy or the puerperium will be highlighted.