Implementation of Tenecteplase for Acute Ischemic Stroke Treatment

INTRODUCTION

Acute ischemic stroke is a neurologic emergency, requiring rapid recognition and treatment with intravenous thrombolysis. Since the publication of the 2019 American Heart Association/American Stroke Association Guidelines that recommend tenecteplase as an alternative agent, several centers across the United States are transitioning from alteplase to tenecteplase as the agent of choice for thrombolysis in acute ischemic stroke.

METHODS

Our health system transitioned to tenecteplase for the treatment of acute ischemic stroke in 2021 due to increasing evidence for efficacy and potential for improved door-to-needle time. Herein we describe our experience and provide guidance for other institutions to implement this change.

CONCLUSION

Emergency nurses are vital to the care of acute ischemic stroke patients. There are several pharmacologic and logistical differences between alteplase and tenecteplase for this indication. This paper outlines these key differences.

Comparison of nimodipine formulations and administration techniques via enteral feeding tubes in patients with aneurysmal subarachnoid hemorrhage: A multicenter retrospective cohort study

BACKGROUND

Nimodipine improves outcomes following aneurysmal subarachnoid hemorrhage (aSAH) and current guidelines suggest that patients with aSAH receive nimodipine for 21 days. Patients with no difficulty swallowing will swallow the whole capsules or tablets; otherwise, nimodipine liquid must be drawn from capsules, tablets need to be crushed, or the commercially available liquid product be used to facilitate administration through an enteral feeding tube (FT). It is not clear whether these techniques are equivalent. The goal of the study was to determine if different nimodipine formulations and administration techniques were associated with the safety and effectiveness of nimodipine in aSAH.

METHODS

This was a retrospective multicenter observational cohort study conducted in 21 hospitals across North America. Patients admitted with aSAH and received nimodipine by FT for ≥3 days were included. Patient demographics, disease severity, nimodipine administration, and study outcomes were collected. Safety end points included the prevalence of diarrhea and nimodipine dose reduction or discontinuation secondary to blood pressure reduction. Predictors of the study outcomes were analyzed using regression modeling.

RESULTS

A total of 727 patients were included. Administration of nimodipine liquid product was independently associated with higher prevalence of diarrhea compared to other administration techniques/formulations (Odds ratio [OR] 2.28, 95% confidence interval [CI] 1.41-3.67, p-value = 0.001, OR 2.76, 95% CI 1.37-5.55, p-value = 0.005, for old and new commercially available formulations, respectively). Bedside withdrawal of liquid from nimodipine capsules prior to administration was significantly associated with higher prevalence of nimodipine dose reduction or discontinuation secondary to hypotension (OR 2.82, 95% CI 1.57-5.06, p-value = 0.001). Tablet crushing and bedside withdrawal of liquid from capsules prior to administration were associated with increased odds of delayed cerebral ischemia (OR 6.66, 95% CI 3.48-12.74, p-value <0.0001 and OR 3.92, 95% CI 2.05-7.52, p-value <0.0001, respectively).

CONCLUSIONS

Our findings suggest that enteral nimodipine formulations and administration techniques might not be equivalent. This could be attributed to excipient differences, inconsistency and inaccuracy in medication administration, and altered nimodipine bioavailability. Further studies are needed.

Angle of progression measured using transperineal ultrasound for prediction of uncomplicated operative vaginal delivery: systematic review and meta-analysis

OBJECTIVE

To determine whether intrapartum transperineal ultrasound measurement of the angle of progression (AoP) during the second stage of labor can predict uncomplicated operative vaginal delivery (OVD) using vacuum or forceps extraction.

METHODS

A systematic search in PubMed, EMBASE, Scopus, Web of Science and Google Scholar was performed from inception to February 2021. Studies assessing the predictive accuracy of AoP, measured using intrapartum transperineal ultrasound, for uncomplicated OVD, defined as successful vaginal delivery within three pulls using forceps or no more than two detachments of the vacuum extractor cup, were included. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. Summary receiver-operating-characteristics (ROC) curves, pooled sensitivity and specificity, area under the ROC curve (AUC) and summary likelihood ratios (LRs) were calculated.

RESULTS

Seven studies reporting on a total of 782 patients undergoing OVD were included in this systematic review and meta-analysis. Second-stage AoP measured during maternal rest had a pooled sensitivity of 80% (95% CI, 59-92%) and specificity of 89% (95% CI, 76-95%), with a LR+ of 7.3 (95% CI, 3.1-15.8) for uncomplicated OVD. AoP measured during active pushing had a sensitivity of 91% (95% CI, 85-94%) and specificity of 83% (95% CI, 69-92%), with a LR+ of 5.4 (95% CI, 2.7-10.6) for uncomplicated OVD. The performance of AoP measured at rest was particularly high in nulliparous women, with a sensitivity of 87% (95% CI, 75-94%) and specificity of 90% (95% CI, 82-94%) for uncomplicated OVD.

CONCLUSION

AoP may be a reliable predictor for uncomplicated OVD when measured during the second stage of labor, especially in nulliparous women. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Fetal heart rate mirrors maternal temperature during posterior fossa craniotomy: a case report

While it is well known that maternal temperature affects fetal heart rate, the exact relationship is not well described. The circumstances accompanying most cases of maternal hypothermia and rewarming (e.g. a drowning event) have precluded a precise quantitative description of this relationship. We describe hypothermia and controlled rewarming during resection of a maternal brain stem tumor in the early third trimester. Continuous electronic fetal heart rate and core temperature monitoring demonstrated a near linear relationship during the development of hypothermia and rewarming. Recognition of the close relationship between maternal temperature and fetal heart rate can help safeguard maternal and fetal health, and prevent unnecessary delivery during non-obstetric surgery in pregnancy.

Stress-Related Gastrointestinal Bleeding in Patients with Aneurysmal Subarachnoid Hemorrhage: A Multicenter Retrospective Observational Study

BACKGROUND/OBJECTIVE

Stress-related mucosal bleeding (SRMB) occurs in approximately 2-4% of critically ill patients. Patients with aneurysmal subarachnoid hemorrhage (aSAH) have a (diffuse) space-occupying lesion, are critically ill, often require mechanical ventilation, and frequently receive anticoagulation or antiplatelet therapy after aneurysm embolization, all of which may be risk factors for SRMB. However, no studies have evaluated SRMB in patients with aSAH. Aims of the study were to determine the incidence of SRMB in aSAH patients, evaluate the effect of acid suppression on SRMB, and identify specific risk factors for SRMB.

METHODS

This was a multicenter, retrospective, observational study conducted across 17 centers. Each center reviewed up to 50 of the most recent cases of aSAH. Patients with length of stay (LOS) < 48 h or active GI bleeding on admission were excluded. Variables related to demographics, aSAH severity, gastrointestinal (GI) bleeding, provision of SRMB prophylaxis, adverse events, intensive care unit (ICU), and hospital LOS were collected for the first 21 days of admission or until hospital discharge, whichever came first. Descriptive statistics were used to analyze the data. A multivariate logistic regression modeling was utilized to examine the relationship between specific risk factors and the incidence of clinically important GI bleeding in patients with aSAH.

RESULTS

A total of 627 patients were included. The overall incidence of clinically important GI bleeding was 4.9%. Of the patients with clinically important GI bleeding, 19 (61%) received pharmacologic prophylaxis prior to evidence of GI bleeding, while 12 (39%) were not on pharmacologic prophylaxis at the onset of GI bleeding. Patients who received an acid suppressant agent were less likely to experience GI bleeding than patients who did not receive pharmacologic prophylaxis prior to evidence of bleeding (OR 0.39, 95% CI 0.18-0.83). The multivariate regression analysis identified any instance of elevated intracranial pressure, creatinine clearance < 60 ml/min and the incidence of cerebral vasospasm as specific risk factors associated with GI bleeding. Cerebral vasospasm has not previously been described as a risk for GI bleeding (OR 2.5 95% CI 1.09-5.79).

CONCLUSIONS

Clinically important GI bleeding occurred in 4.9% of patients with aSAH, similar to the general critical care population. Risk factors associated with GI bleeding were prolonged mechanical ventilation (> 48 h), creatinine clearance < 60 ml/min, presence of coagulopathy, elevation of intracranial pressure, and cerebral vasospasm. Further prospective research is needed to confirm this observation within this patient population.

Using First Principles to Link Silicone Oil/Formulation Interfacial Tension With Syringe Functionality in Pre-Filled Syringes Systems

Numerous interactions can arise at the interface between the glass barrel/silicone oil coating/aqueous formulation in pre-filled syringes that can affect the functionality of the medical device. In this study, the Young-Dupré equation was applied at these interfaces to correlate the interfacial tension between the silicone oil coating and aqueous formulation to the functionality of the syringe. It was shown that lower silicone oil/drug product formulation interfacial tension led to an increase in the glide force of the syringe. The relationship between glide force profiles and silicone oil thickness after injection was also investigated and the data revealed that the silicone oil was removed at the end of the syringe barrel when the formulation contains polysorbate 80.

Collaborative Management Strategies for Drug Shortages in Neurocritical Care

Drug shortages have become all too familiar in the health care environment, with over 200 drugs currently on shortage. In the wake of Hurricane Maria in September 2017, hospitals across the USA had to quickly and creatively adjust medication preparation and administration techniques in light of decreased availability of intravenous (IV) bags used for compounding a vast amount of medications. Amino acid preparations, essential for compounding parenteral nutrition, were also directly impacted by the hurricane. Upon realization of the impending drug shortages, hospitals resorted to alternative methods of drug administration, such as IV push routes, formulary substitutions, or alternative drug therapies in hopes of preserving the small supply of IV bags available and prioritizing them for them most critical needs. In some cases, alternative drug therapies were required, which increased the risk of medication errors due to the use of less-familiar treatment options. Clinical pharmacists rounding with medical teams provided essential, patient-specific drug regimen alternatives to help preserve a dwindling supply while ensuring use in the most critical cases. Drug shortages also frequently occur in the setting of manufacturing delays or discontinuation and drug recalls, with potential to negatively impact patient care. The seriousness of the drug shortage crisis reached public attention by December 2017, when political and pharmacy organizations called for response to the national drug shortage crisis. In this article, we review institutional mitigation strategies in response to drug shortages and discuss downstream effects of these shortages, focusing on medications commonly prescribed in neurocritical care patients.

Abstract P3-03-10: Pre-operative lymphoscintigraphy for sentinel lymph node localisation: Is it necessary?

Introduction

Sentinel lymph node biopsy (SLNB) has replaced lymph node clearance for staging of the axilla in patients with early invasive breast cancer and no evidence of lymph node involvement on ultrasound or needle biopsy. It is recommended that a dual technique, using isotope and blue dye, is used to locate the sentinel lymph node (SLN) intra-operatively. Often, at the time of radioisotope injection, a lymphoscintigram (nuclear medicine scan) is obtained to demonstrate the 'hot' sentinel lymph node with or without skin marking of its anatomical position.

Performing a lymphoscintigram adds time and cost to the localisation process. In our centre, this investigation costs £899-999 (˜US $1180-1300).

Aims

The aim of this study is to find out whether obtaining a pre-operative lymphoscintigram aids the surgeon in the localisation of the SLN or affects the number of sentinel lymph nodes biopsied in the axillary staging of patients with early invasive breast cancer.

Methods

We carried out a retrospective study of patients who underwent SLNB for breast cancer in our hospital Trust between March 2012 and November 2017. We identified those patients who had a lymphoscintigram performed pre-operatively for SLN localisation. We recorded the number of SLNs identified on imaging and compared this with the number of SLNs biopsied during the operation.

Results

349 patients underwent 354 SLNBs during the study period. One patient was male, the remainders were female. The mean age of patients was 57.2 years (range 25 to 98 years).

In 295 (83.3%) cases, a lymphoscintigram was obtained prior to SLNB for node localisation, and 268 (90.8%) of these scans were able to identify one or more SLNs. In 173 (58.6%) scans, a single SLN was identified. In 27 (9.1%) scans it was either unclear how many SLNs were demonstrated or no SLNs were seen (16/295 no SLN identified, 11/295 unclear how many SLNs).

In 102 (34.6%) cases, the number of SLNs biopsied matched the number of SLNs identified on imaging. Of those that did not match, 76.2% had more and 15.0% fewer SLNs excised than shown on imaging. In 8.8% it was unknown if the number of SLNs matched that seen on imaging due to lack of histopathology results.

Conclusion

Lymphoscintigraphy for SLN localisation is costly and time consuming. In a high proportion of cases, number of SLNs identified on imaging does not match the number biopsied and thus, we suggest, that it is not required prior to SLNB and should be removed from practice.

Citation Format: Clark SL, Yilmaz D, Arun K, Javadzadeh S, Saeed S, Ullah MZ. Pre-operative lymphoscintigraphy for sentinel lymph node localisation: Is it necessary? [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-10.

Bags versus flasks: a comparison of cell culture systems for the production of dendritic cell-based immunotherapies

In recent years, cell-based therapies targeting the immune system have emerged as promising strategies for cancer treatment. This review summarizes manufacturing challenges related to production of antigen presenting cells as a patient-tailored cancer therapy. Understanding cell-material interactions is essential because in vitro cell culture manipulations to obtain mature antigen-producing cells can significantly alter their in vivo performance. Traditional antigen-producing cell culture protocols often rely on cell adhesion to surface-treated hydrophilic polystyrene flasks. More recent commercial and investigational cancer immunotherapy products were manufactured using suspension cell culture in closed hydrophobic fluoropolymer bags. The shift to closed cell culture systems can decrease risks of contamination by individual operators, as well as facilitate scale-up and automation. Selecting closed cell culture bags over traditional open culture systems entails different handling procedures and processing controls, which can affect product quality. Changes in culture vessels also entail changes in vessel materials and geometry, which may alter the cell microenvironment and resulting cell fate decisions. Strategically designed culture systems will pave the way for the generation of more sophisticated and highly potent cell-based cancer vaccines. As an increasing number of cell-based therapies enter the clinic, the selection of appropriate cell culture vessels and materials becomes a critical consideration that can impact the therapeutic efficacy of the product, and hence clinical outcomes and patient quality of life.

Ultrafast Transient Absorption Spectroscopy of the Sunscreen Constituent Ethylhexyl Triazone

The ultrafast photoprotection mechanisms in operation in ethylhexyl triazone (EHT, octyl triazone), an approved ultraviolet-B (UV-B) chemical filter for commercial sunscreens, remain elusive, with a notable absence of ultrafast time-resolved measurements. These large organic molecules are of increasing interest as they are suspected to be less likely to penetrate the skin than some of the smaller approved filters, thereby reducing the possible adverse effects from sunscreen products. We apply femtosecond transient absorption spectroscopy with electronic structure calculations to unravel the complete photodeactivation mechanism that EHT undergoes after UV-B irradiation. We propose that this involves ultrafast internal conversion of the initially photoexcited n¹ππ* state that couples to the ground state via a 1¹ππ*/S₀ conical intersection, enabling multiple absorption and recovery cycles, as one would anticipate from a highly efficient filter. We also observe long-lived photoproducts which, based on previous studies along with present electronic structure calculations, we attribute to trapped excited populations in the S₁ and T₁ states.

IV fosphenytoin in obese patients: Dosing strategies, safety, and efficacy

Background

Previous studies evaluated the disposition of IV phenytoin loading doses and found that obese patients had increased drug distribution into excess body weight, larger volumes of distribution, and longer half-lives when compared to their nonobese counterparts. We assess the safety and efficacy of fosphenytoin loading doses in patients with different body mass indices (BMIs).

Methods

A retrospective chart review was conducted in 410 patients who received fosphenytoin. Patients were divided into 2 groups: BMI <30 (nonobese) and BMI ≥30 (obese). Patient demographics, fosphenytoin dose administered in mg/kg body weight, renal and liver function tests, fosphenytoin drug levels, and pre- and post-fosphenytoin administration vital signs were collected to assess for adverse events. Necessity of additional antiepileptic loading doses was used as a surrogate for clinical efficacy.

Results

The median dose of fosphenytoin administered was 19 mg/kg (interquartile range 15-20). The most frequently encountered adverse event was hypotension, which occurred in 39% of the cohort. Using a Bonferroni adjustment for multiple comparisons, there were no differences in adverse events between the 2 groups. The need for additional antiepileptic loading doses was not different between the 2 groups (p = 0.07).

Conclusions

The incidence of adverse events and the need for repeat loading antiepileptic medications was similar between the 2 groups. From our findings, the patients in our study did not receive empiric loading dose adjustments and the current method of loading fosphenytoin achieves similar outcomes, regardless of the patient's BMI.

Airway management for cesarean delivery performed under general anesthesia

BACKGROUND

With the increasing popularity of neuraxial anesthesia, there has been a decline in the use of general anesthesia for cesarean delivery. We sought to examine the incidence, outcome and characteristics associated with a failed airway in patients undergoing cesarean delivery under general anesthesia.

METHODS

A retrospective review of airway management in women undergoing cesarean delivery under general anesthesia over an eight-year period from 2006-2013 at an academic medical center was conducted.

RESULTS

During the study period, 10 077 cesarean deliveries were performed. Neuraxial anesthesia was used in 9382 (93%) women while general anesthesia was used in 695 (7%). Emergent cesarean delivery was the most common indication for general anesthesia. Failed intubation was encountered in only three (0.4%) women, who were successfully managed with a laryngeal mask airway. The overall incidence of failed intubation was 1 in 232 (95% CI 1:83 to 1:666) and general anesthesia was continued in all cases. There were no adverse maternal or fetal outcomes directly related to failed intubation.

CONCLUSION

Advances in adjunct airway equipment, availability of an experienced anesthesiologist and simulation-based teaching of failed airway management in obstetrics may have contributed to our improved maternal outcomes in patients undergoing cesarean delivery under general anesthesia.

A Case of Severe, Prolonged, Refractory Hypophosphatemia After Zoledronic Acid Administration

Zoledronic acid (ZA) administration has been associated with electrolyte abnormalities, including hypocalcemia, hypomagnesemia, hypokalemia, and hypophosphatemia. We describe a case of severe, refractory hypophosphatemia in a patient who received ZA for hypercalcemia of malignancy (HCM). Little data are available that describe the incidence or degree of severity of hypophosphatemia that can occur following ZA administration. In addition, no formal recommendations exist to guide monitoring for or management of electrolyte derangements in the setting of bisphosphonate use. Our patient required daily, high-dose phosphorus replacement beginning day 4 following ZA administration. The average daily dose of phosphorus, including both intravenous and enteral administration, was highest in the first 2 weeks after ZA, averaging 77 mmol/d days 4 through 15, and does not include sources of phosphorus from the patient’s nutrition support. Despite this high amount of supplementation, which was well beyond what meets normal daily requirements and the amount expected to treat “usual” hypophosphatemia, the patient did not achieve sustained normal serum phosphorus levels for over 30 days after ZA. ZA is a favorable option for treating HCM because of its longer duration of action, potent serum calcium-lowering effects, and favorable safety profile. The risk of hypophosphatemia with ZA use is reviewed.

Safety of intravenous immunoglobulin and plasma exchange in critically ill patients

OBJECTIVE

To assess the safety profile of intravenous immunoglobulin (IVIG) and plasma exchange (PLEX) when used to treat critically ill patients.

METHODS

We performed a retrospective analysis of consecutive patients who received IVIG or PLEX while admitted to our medical intensive care unit (ICU), neuroscience ICU or haematologic/oncologic ICU between 2007 and 2011.Patients who were transferred into an ICU while receiving therapy or who continued therapy after discharge from the ICU were included in the analysis.

RESULTS

A total of 118 consecutive patients were included in the study. Fifty-nine patients received IVIG. Twenty of these patients (34%) developed renal failure during the hospitalisation, including 15 (25.4%) in whom renal function worsened during or shortly after IVIG administration and 4 (6.8%) in whom IVIG was considered a possible cause. Transfusion reactions occurred in five patients (8%). Seven patients (12%) did not receive the full intended course of IVIG. Thirty-four patients (58%) who received IVIG died during their hospitalisation. Fifty-nine patients received PLEX. Hypotension requiring an intervention was noted with 39 sessions (8.5%) and led to discontinuation of the session in 11 (2.4%). Other adverse events included line-related infections (n = 4), pneumothorax (n = 4) and electrolyte abnormalities and transfusion reactions (n = 10). Six patients (10%) did not receive full intended treatment course of PLEX. Nineteen patients (32%) treated with PLEX died during their hospitalisation.

DISCUSSION

Intravenous immunoglobulin and PLEX are generally well tolerated by critically ill patients. Intravenous immunoglobulin was associated with worsening renal function in one-quarter of patients.

Cefepime neurotoxicity in the intensive care unit: a cause of severe, underappreciated encephalopathy

Introduction

Cefepime, a broad spectrum antibiotic, is commonly prescribed in intensive care units (ICU) and may be an overlooked cause of neurologic symptoms such as encephalopathy, myoclonus, seizures, and coma. We aimed to characterize cefepime neurotoxicity in the ICU.

Methods

We performed a retrospective study of adult ICU patients treated with intravenous cefepime for at least 3 days between January 1, 2009 and December 31, 2011. The primary outcome was the development of cefepime neurotoxicity, with the likelihood of causality ascribed via a modified Delphi method.

Results

This study included 100 patients. The mean age was 65.8 years (± 12.7 years). The median daily average dose of cefepime was 2.5 (IQR 2.0 to 3.5) grams. The median treatment duration was 6 (IQR 4 to 10) days. Renal failure in any form was present in 84 patients. Chronic kidney disease affected 40 patients, and 77 had acute kidney injury. Cefepime neurotoxicity occurred in 15 patients. Of these, seven were considered definite cases, three probable, and five possible. Neurotoxic symptoms included impaired consciousness (n = 13), myoclonus (n = 11), disorientation (n = 6), and nonconvulsive status epilepticus (n = 1). The dose of cefepime was appropriately adjusted for renal clearance in 64 patients (75.3%) without cefepime neurotoxicity and four patients (28.6%) with neurotoxicity (P = 0.001). Chronic kidney disease was present in 30 patients (35.3%) without neurotoxicity and in 10 (66.7%) of those with neurotoxicity (P = 0.04).

Conclusions

Critically ill patients with chronic kidney disease are particularly susceptible to cefepime neurotoxicity. Myoclonus and impaired consciousness are the predominant clinical manifestations. Neurotoxic symptoms occur more often when the cefepime dose is not adjusted for renal function, but can still occur despite those modifications.

Pharmacogenomic study of side-effects for antidepressant treatment options in STAR*D

BACKGROUND

Understanding individual differences in susceptibility to antidepressant therapy side-effects is essential to optimize the treatment of depression.

METHOD

We performed genome-wide association studies (GWAS) to search for genetic variation affecting the susceptibility to side-effects. The analysis sample consisted of 1439 depression patients, successfully genotyped for 421K single nucleotide polymorphisms (SNPs), from the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study. Outcomes included four indicators of side-effects: general side-effect burden, sexual side-effects, dizziness and vision/hearing-related side-effects. Our criterion for genome-wide significance was a prespecified threshold ensuring that, on average, only 10% of the significant findings are false discoveries.

RESULTS

Thirty-four SNPs satisfied this criterion. The top finding indicated that 10 SNPs in SACM1L mediated the effects of bupropion on sexual side-effects (p = 4.98 × 10(-7), q = 0.023). Suggestive findings were also found for SNPs in MAGI2, DTWD1, WDFY4 and CHL1.

CONCLUSIONS

Although our findings require replication and functional validation, this study demonstrates the potential of GWAS to discover genes and pathways that could mediate adverse effects of antidepressant medication.

Electrolyte orders in the neuroscience intensive care unit: worth the value or waste?

BACKGROUND

To assess the value of the practice of obtaining frequent electrolyte measurements in patients with extended stay in a neuroscience intensive care unit (NICU).

METHODS

We identified consecutive patients 18 years or older, admitted to the NICU between January 1 and July 31, 2009 with length of stay ≥ 5 days. We collected potassium, sodium, magnesium, ionized calcium, phosphorus laboratory measurements and hemoglobin levels, and recorded electrolyte replacement orders and red blood cell transfusions. Average laboratory costs were estimated.

RESULTS

93 patients were included in the study (54 men, mean age 54 years, range 18-85 years). Mean length of stay was 10.4 days (range 5-36 days). Sodium and potassium were the electrolytes most frequently measured (averages of 14.1 and 13.1 per patient, respectively). More than 75% of the results were within normal range for all electrolytes measured and critical values were extremely uncommon. The number of phlebotomies for electrolyte measurements was strongly associated with the degree of hemoglobin drop (P < 0.0001). Electrolyte panels were ordered much more often than individual electrolytes with average cost exceeding $2200 per patient. Replacing half of these electrolyte panels with single sodium or potassium orders would have resulted in savings greater than $100,000 in our population.

CONCLUSIONS

Electrolytes measurements are very frequent in the NICU, but results are most often normal and only exceptionally critical. The phlebotomies required for these tests significantly worsen hemoglobin levels. A more conservative use of electrolyte measurements can result in reduction of blood loss and substantial cost savings.

A report on dental anxiety levels in children undergoing nitrous oxide inhalation sedation and propofol target controlled infusion intravenous sedation

AIM

To report on two separate child sedation cohorts; one undergoing propofol intravenous sedation (IVS) and the other, nitrous oxide inhalation sedation (IS) in respect to changes in dental anxiety and subject characteristics.

STUDY DESIGN

The age, gender, level of social deprivation and amount of treatment performed and observed patient behaviour during treatment, using the Frankl and a VAS scale, were recorded for each subject. Anxiety questionnaires were completed before and after treatment. These were: - Modified Child Dental Anxiety Scale (MCDAS); Children's Fear Survey Schedule- Dental Subscale (CFSS-DS) and two Visual Analogue Scales (VAS).

RESULTS AND STATISTICS

Participants (36) attended for treatment under IS and 40 attended for treatment under propofol IVS. The IVS cohort was older (p<0.01), by between 1.9 and 4.1 years and had more treatment [p = 0.015, 95% confidence interval for the difference between the cohort medians was (0, 3) units]. The two cohorts were closely matched in respect to pre-operative anxiety as measured by the MCDAS and CFSS-DS scales. There were significant anxiety reductions within each cohort as measured by three of the scales: - MCDAS, CFSS-DS and VAS (1) (p< or = 0.001) but no significant change in the VAS (2) scores. When the two cohorts were compared, there was no significant difference in the reduction of the self-reported anxiety for any of the four scales (p>0.05). The observed behaviour was good for both cohorts.

CONCLUSION

Propofol target-controlled intravenous sedation and nitrous oxide inhalation sedation were similarly efficacious at anxiety reduction in referred dentally anxious children. Subjects undergoing propofol IVS were older than those undergoing IS. Propofol TCI may offer the opportunity for more treatment at each visit. Further propofol TCI conscious sedation studies are required.

Induction of intestinal rotavirus-specific antibodies in respiratory, but not gut, lymphoid tissues following mucosal immunization of mice with inactivated rotavirus

Intranasal (i.n.), but not oral, immunization of mice with inactivated rotavirus induces protection against challenge. To understand the mechanisms by which i.n. immunization with inactivated rotavirus evokes protective immunity, we examined the site of rotavirus-specific B cell activation and the origins of intestinal IgA-secreting B cells following i.n. inoculation of mice with inactivated rhesus rotavirus. We found that (1) i.n., but not oral, inoculation induced partial protection after challenge; (2) i.n., but not oral, inoculation induced production of rotavirus-specific IgM, IgA, and IgG by intestinal lymphoid tissues; and (3) after i.n. inoculation, nasal-associated lymphoid tissues (NALT) and bronchial lymph nodes (BLN) were the sites of initial production of rotavirus-specific antibodies. These studies indicate that after inoculation with inactivated rotavirus, virus-specific effector B cells may be more easily activated in respiratory, compared to intestinal, lymphoid tissues. Additional studies are needed to determine if these observations are due to fundamental differences in the microenvironment of NALT and BLN compared to Peyer's patches or are a function of the anatomic differences between the respiratory and the gastrointestinal tracts.

Tissue and cellular alterations in Asian clam (Potamocorbula amurensis) from San Francisco Bay: toxicological indicators of exposure and effect?

The US Geological Survey has reported the presence of a metal contamination gradient in clam tissues, decreased condition indices, and irregular reproductive patterns have been reported in the Asian clam, Potamocorbula amurensis, from San Francisco Bay. If metals are driving the observed patterns in the field, then biomarkers of exposure, and possibly deleterious effect, should show a corresponding gradient. In this study, biomarkers from sub-cellular to tissue levels of biological organization were assessed in P. amurensis collected from the Bay or exposed to cadmium in the laboratory. Cellular and tissue alterations were assessed using histopathology and enzyme histochemistry (EH). Alterations in the ovary, testis, kidney, and gill tissues were most common at the most contaminated station when data were averaged over a 12-month sampling period. EH analysis indicated decreased active transport, energy status, and glucose oxidation in kidney and digestive gland at the most contaminated site which may indicate a decreased potential for growth. Ovarian lesions observed in feral Asian clams were experimentally induced in healthy clams by cadmium exposure in laboratory exposures. Our results suggest a contaminant etiology for tissue alterations.

Coumarin derivatives and breast-feeding

Coumarin derivatives are the anticoagulants most widely used in the United States. These agents are relatively contraindicated during pregnancy, and the use of these drugs in breast-feeding women remains controversial. Much of the confusion regarding the passage of these agents into breast milk might stem from the fact that different agents possess significantly different chemical properties. A review of the chemical structure of different coumarin derivatives, as well as available clinical evidence, suggests that warfarin sodium is not excreted into breast milk, and can be safely given to women requiring therapeutic anticoagulation postpartum. For the rare patient who cannot tolerate warfarin sodium, the use of dicumarol, rather than anisindione, is preferred.

Is vaginal birth after cesarean less expensive than repeat cesarean delivery?

OBJECTIVE

This study was undertaken to compare total medical costs of trial of labor after cesarean with those of elective repeat cesarean without labor, with both short- and long-term neonatal costs associated with such procedures taken into account.

STUDY DESIGN

Costs associated with All Patient Refined diagnosis-related groups and Current Procedural Terminology for a large not-for-profit health care system were applied to an algorithm describing maternal and neonatal outcomes of trial of labor. Perinatal morbidity rates and cost estimates for long-term neurologic damage associated with uterine rupture were derived from published literature.

RESULTS

If a 70% vaginal birth rate for women undergoing a trial of labor and delivery in a tertiary center with a mean uterine rupture to delivery time of 13 minutes is assumed, the net cost differential ranged from a saving of $149 to a loss of $217, depending on morbidity assumptions. For vaginal birth after cesarean success rates <70%, trial of labor in the presence of two previous scars, and institutional factors increasing the perinatal morbidity rate by just 4% with respect to that seen in tertiary centers, trial of labor resulted in a net financial loss to the health care system regardless of all other assumptions made.

CONCLUSIONS

When costs as opposed to charges are considered and the cost of long-term care for neurologically injured infants is taken into account, trial of labor after previous cesarean is unlikely to be associated with a significant cost saving for the health care system. Recent government-mandated length-of-stay requirements are likely to make the economic benefit of vaginal birth after cesarean even less favorable. Factors other than cost must govern decisions regarding trial of labor or repeat cesarean.

Vibroacoustic and scalp stimulation

Both VAS and scalp stimulation are useful in the evaluation of fetal compromise by decreasing the number of falsely abnormal FHR tests and limiting the number of unnecessary interventions, thus improving the efficiency of antepartum and intrapartum FHR monitoring. As is true for all types of fetal assessment using FHR monitoring, VAS and scalp stimulation have limitations, and a lack of response to these methodologies does not necessarily indicate fetal acidemia. When either VAS or scalp stimulation is employed, one must take into consideration their respective predictive values (see Table 1). Fetal VAS or scalp stimulation should be considered as one facet of comprehensive fetal evaluation. When these techniques are used in this manner, the clinician evaluating the fetus in the antepartum or intrapartum period may prevent unnecessary intervention and improve maternal and neonatal outcome.

Migration of antigen-presenting B cells from peripheral to mucosal lymphoid tissues may induce intestinal antigen-specific IgA following parenteral immunization

Parenterally administered immunizations have long been used to induce protection from mucosal pathogens such as Bordetella pertussis and influenza virus. We previously found that i.m. inoculation of mice with the intestinal pathogen, rotavirus, induced virus-specific Ab production by intestinal lymphocytes. We have now used adoptive transfer studies to identify the cell types responsible for the generation of virus-specific Ab production by gut-associated lymphoid tissue (GALT) after i.m. immunization. Three days after i.m. immunization with rotavirus, cells obtained from the draining peripheral lymph nodes of donor mice were transferred into naive recipient mice. We found that intestinal lymphocytes produced rotavirus-specific Igs (IgM, IgA, and IgG) 2 wk after transfer of either unfractionated cells, or unfractionated cells rendered incapable of cellular division by mitomycin C treatment. Additional studies demonstrated that rotavirus-specific IgA, but not IgG, was produced by intestinal lymphocytes after transfer of purified B cells. Ig allotype analysis revealed that rotavirus-specific IgA was produced by intestinal B cells of recipient origin, suggesting that migration of Ag-presenting B cells from peripheral lymphoid tissues to GALT may contribute to the generation of mucosal IgA responses after parenteral immunization. Strategies that promote Ag uptake and presentation by B cells may enhance mucosal IgA production following parenteral immunization.

Maternal oxygen transport variables during the third trimester of normal pregnancy

OBJECTIVE

The aim of this study was to measure and calculate oxygen transport variables in uncomplicated term pregnancies.

STUDY DESIGN

Ten normotensive primiparous women between 36 and 38 weeks' gestation underwent pulmonary and radial arterial catheterization as part of a larger study. Seven women had studies repeated at approximately 12 weeks post partum. Measurements were made with patients in the left lateral recumbent position after a 30-minute stabilization period. Cardiac output was measured with the thermodilution technique. Blood samples were obtained simultaneously from the pulmonary and radial arteries and analyzed in duplicate for oxygen content with a blood gas analyzer.

RESULTS

The oxygen contents of both arterial and mixed venous blood are significantly lower (P <.05) in the third trimester of pregnancy (15.96 and 11.97 mL/dL, respectively) than in the postpartum period (18.00 and 13.54 mL/dL). The fall in oxygen content during pregnancy prevents any significant increase in oxygen delivery in the third trimester (867. 59 mL/min) relative to the postpartum period (806.50 mL/min, P not significant).

CONCLUSION

This is the first report of directly measured oxygen transport variables in healthy pregnant women.

Institutional influences on the primary cesarean section rate in Utah, 1992 to 1995

OBJECTIVES

Our purpose was to evaluate institutional and organizational influences on cesarean section rates in Utah and to adjust such rates for differences in patient acuity.

STUDY DESIGN

Data on cesarean section rates were derived from the Utah Hospital Discharge Database and adjusted for patient acuity by correcting raw cesarean rates for those patients undergoing cesarean section meeting regional gestational age transport criteria.

RESULTS

When analyzed by means of 1-way analysis of variance, the following factors had a significant negative correlation (P < .05) with cesarean section rate: presence of a newborn intensive care unit and maternal-fetal medicine subspecialists, presence on the medical staff of obstetrician-gynecologist(s) as opposed to family physicians only, delivery volume >1500/y, urban location, and 24-hour in-house anesthesiology. When cesarean rates were corrected for acuity, facilities with maternal-fetal medicine specialists and a newborn intensive care unit had significantly lower rates (P < .001) and more uniform rates than otherwise similar institutions.

CONCLUSIONS

More medically sophisticated physicians and institutions have lower cesarean rates when patient acuity is taken into account.

Videoconferencing: practical advice on implementation

Videoconferencing provides a useful tool for improving information flow, with clinical, educational and administrative uses being particularly relevant to rural and remote Australia. This paper describes the range of possible uses for computer-based videoconferencing and describes the authors' experience in delivering rural medical education in North Queensland via videoconference. Principles that ensure successful videoconferencing are outlined and are applicable to a variety of formats and uses. They include the need to keep it simple, the importance of thorough preparation, and ensuring that education drives technology, rather than the converse.

A prospective evaluation of fetal pericardial fluid in 506 second-trimester low-risk pregnancies

OBJECTIVE

To measure fetal pericardial fluid in low-risk second-trimester pregnancies and to evaluate outcome for those with measurements greater than 2 mm.

METHODS

Five hundred and six women were referred for sonography between 16 and 25 weeks' gestation for common obstetric indications (dating, fetal survey, and placental location) unrelated to an increased risk of anomalies. All cases were evaluated with two-dimensional and M-mode real-time ultrasonography with the use of a mechanical sector transducer. The maximum distance of the fetal hypoechoic cardiac rim was recorded. We reviewed maternal and infant charts for those with measurements greater than 2 mm.

RESULTS

Median (range) maternal age was 25 (15-42) years. Median gravidity and parity were two (1-14) and one (0-11), respectively. Median estimated gestational age was 20.4 (16.3-24.9) weeks. Fetal pericardial fluid was seen in 360 of 506 (71%) fetuses. Of these 360 fetuses, the mean distance (+/- 2 standard deviation) of the fetal hypoechoic cardiac rim was 1.20 mm +/- 0.91 mm (95% confidence interval 1.15, 1.25). Among the 506 cases, the maximum measurement was 3 mm. Ten of the 506 (2%) cases had measurements greater than 2 mm. None of these ten fetuses had a cardiac structural abnormality or arrhythmia, and perinatal outcome was unremarkable.

CONCLUSION

During second-trimester fetal ultrasonographic examination, visualization of pericardial fluid up to 2 mm in the fetus with current high-resolution technology is common and should not be regarded as pathologic.

Monitoring wound healing by odour

A pilot study using electronic aroma detection was performed over a six-month period to assess the aroma of chronic non-healing venous leg ulcers and the effect of appropriate antibiotic therapy on modification of the aroma. Deep infection with pathogenic organisms was found on biopsy culture in 13 out of 15 patients. Odour analysis was performed at weekly intervals on the ulcer dressings using an AromaScan instrument. Data points on the aroma maps moved from their pre-treatment presentation. Alterations in aroma data correlated well with the progress of the ulcers. Aroma analysis is shown to be a potential tool in monitoring the progress towards healing of chronic venous ulcers.

Current status of the multicenter randomized clinical trial on fetal oxygen saturation monitoring in the United States

Current clinical methods of intrapartum fetal assessment are sensitive but poorly specific in detecting fetal compromise during labor. These limitations have substantially contributed to the escalating cesarean section rate which occurred in the US during the last several decades. Experimental and clinical research efforts directed towards application of the oxygen saturation monitor (pulse oximeter) to intrapartum fetal assessment have produced encouraging results. If this new method of fetal assessment is to enter the clinical arena, safety and efficacy issues must first be properly evaluated via randomized clinical trials. The purpose of this report is to describe the design of a multicenter randomized clinical trial of intrapartum fetal oxygen saturation monitoring recently begun in the US. Specific aspects of the trial, including purpose, study design, sample size estimates, control and test groups, inclusion and exclusion criteria, fetal heart rate classification, definition of normal fetal arterial oxygen saturation (SpO2), clinical management protocol, and assessment of maternal-fetal outcomes will be addressed.

Prospective evaluation of the antenatal incidence and postnatal significance of the fetal echogenic cardiac focus: a case-control study

OBJECTIVE

We evaluated the antenatal incidence and postnatal significance of echogenic cardiac foci observed during antenatal ultrasonography.

STUDY DESIGN

During a 4-month period, all women undergoing dating ultrasonography between 16.0 and 24.9 weeks' gestation at one referral center were prospectively evaluated for an echogenic cardiac focus during an apical four-chamber view of the heart. Referrals for maternal or fetal complications were excluded. Postnatal echocardiography was performed for those identified with positive findings. Controls were selected from among normal subjects in the general group for comparison with the study group.

RESULTS

Five hundred six consecutive fetuses were evaluated at a mean +/- SD gestational age of 20.6 +/- 1.6 weeks. There were 25 (4.9%) fetuses found to have echogenic cardiac focus (left ventricle = 19, right ventricle = 6). Echocardiography was performed between 0.3 and 20.1 weeks postdelivery. After birth, 12 echogenic left ventricle papillary muscles and three echogenic left ventricle chordae were identified; there were no postnatal right ventricle findings. There were no cases of intracardiac tumor or myocardial dysfunction; one neonate had minor structural malformations. There were no significant differences in maternal age, gravidity, parity, gestational age at ultrasonography, gestational age at delivery, or 5-minute Apgar scores. A significant difference was observed in birth weight between the control (n = 50) and study (n = 25) groups (3465 +/- 501 gm vs 3124 +/- 589 gm; p = 0.002). This difference persisted after correcting for gestational age, although all infants in both groups born after 37.0 weeks weighed > 2500 gm.

CONCLUSIONS

The incidence of echogenic cardiac foci during routine midtrimester ultrasonography is 4.9%. As an isolated finding, the echogenic cardiac focus may be associated with a statistically significant but clinically insignificant decrease in birth weight. Because of these findings, we consider an isolated echogenic cardiac focus in a patient at low risk for cardiac abnormalities a variant of normal, which does not warrant follow-up clinical evaluation.

Very advanced maternal age: pregnancy after age 45

OBJECTIVE

Our purpose was to describe the maternal and fetal outcomes of pregnancies in women > or = 45 years old at delivery.

STUDY DESIGN

A retrospective review of in-hospital deliveries after 20 weeks of gestation was performed in four Utah tertiary care hospitals for the 10-year period between 1985 and 1994.

RESULTS

Seventy-nine cases were identified among 126,500 births, with an incidence of 0.63 per 1000 births. Maternal ages were 45 (n = 44), 46 (n = 21), and > or = 47 (n = 14) years. Three of the conceptions were assisted, including both twin gestations. Thirty-seven (46.8%) had obstetric complications during pregnancy; the most frequent complications were gestational diabetes (12.7%) and preeclampsia (10.1%). Median (range) gestational age at delivery was 39 (22.9 to 41.7) weeks; 12 (15.2%) deliveries occurred before 37 weeks. Eight (9.9%) karyotype abnormalities were diagnosed. The cesarean section rate was 31.7%; the most frequent indications were abnormal lie (n = 9), fetal distress (n = 5), and previous cesarean delivery (n = 5). There were no maternal deaths. Median (range) birth weight was 3466 (397 to 5085) gm; 14 (17.3%) were < 2500 gm and 16 (19.8%) were > 4000 gm. Twelve (14.8%) infants were admitted to the neonatal intensive care unit. The corrected perinatal mortality rate was 1.3% (1/78).

CONCLUSIONS

In women > 45 years old at delivery maternal and fetal outcomes were generally good, but there was a high incidence of pregestational (chronic hypertension, hypothyroidism) and gestational (karyotype abnormalities, gestational diabetes, cesarean section, macrosomia) complications. This information may be helpful for counseling women between 45 and 50 years old who are considering pregnancy.

The relationship between oxygen saturation and pH in umbilical blood: implications for intrapartum fetal oxygen saturation monitoring

OBJECTIVE

Our purpose was to evaluate the relationship between umbilical arterial blood oxygen saturation determined by hemoximetry (Sao2) and umbilical arterial blood pH and base excess determined by blood gas analysis to establish a "critical threshold" for fetal preductal arterial oxygen saturation determined by reflectance pulse oximetry (Spo2).

STUDY DESIGN

Umbilical artery and vein blood specimens were obtained at delivery. Blood gas analysis and hemoximetry were performed. Polynomial regression analysis and receiver-operator characteristic curves were calculated for umbilical arterial blood Sao2 and theoretic preductal arterial blood Sao2 versus umbilical arterial blood pH and base excess.

RESULTS

A total of 1101 paired umbilical artery and vein specimens were obtained. When the umbilical arterial blood Sao2 was > or = 30%, umbilical arterial blood pH was > or = 7.13 in 99.0% (388/392) of cases and < 7.13 in 1.0% (4/392) of cases. When umbilical arterial blood Sao2 was < 30%, umbilical arterial blood pH was > or = 7.13 in 91.4% (648/709) of cases and < 7.13 in 8.6% (61/709) of cases.

CONCLUSIONS

From these analyses, it appears that an Spo2 cutoff value of 30% would be reasonable in clinical trials of intrapartum fetal pulse oximetry.

The effects of maternal position and cardiac output on intrapulmonary shunt in normal third-trimester pregnancy

OBJECTIVE

To assess the effect of pregnancy, maternal position, and cardiac output on intrapulmonary shunting (Qs/Qt) in normotensive nulliparous women near term.

METHODS

Ten normotensive nulliparas between 36 and 38 weeks' gestation underwent pulmonary artery catheterization (via the subclavian route) and radial artery canalization. Baseline assessments were made with subjects in the left lateral recumbent position after a 30-minute stabilization period. Measurements were obtained sequentially in the left lateral, right lateral, supine, knee-chest, sitting, and standing positions. Each position change was followed by a 10-minute pre-measurement stabilization period. Cardiac output was measured via the thermodilution technique. Blood samples were obtained simultaneously from the pulmonary and radial arteries and analyzed in duplicate for oxygen content with a blood gas analyzer. Qs/Qt was calculated using the classic shunt equation. Statistical analysis was performed by analysis of variance of repeated measures of Qs/Qt and maternal position. The relationship of Qs/Qt to maternal cardiac output was evaluated by the correlation coefficient. Significance was defined as P < .05.

RESULTS

Directly measured Qs/Qt averaged 15.3% in left lateral, 15.2% in right lateral, 13.9% in supine, 12.8% in knee-chest, 13.8% in sitting, and 13.0% in standing positions. There was no statistically significant correlation between Qs/Qt and cardiac output (R2 = 0.11, not significant).

CONCLUSION

This is the first report of directly measured Qs/Qt in normal pregnant women in the third trimester. Qs/Qt values reported in pregnancy are higher than those reported in nonpregnant individuals.

Third-trimester arterial blood gas and acid base values in normal pregnancy at moderate altitude

OBJECTIVE

To report arterial blood gas and acid base values of normal nulliparous patients at moderate altitude for commonly used maternal positions.

METHODS

Ten normotensive nulliparous women between 36 and 38 weeks' gestation volunteered to undergo radial and pulmonary artery cannulation as part of a larger study. Following instrumentation, baseline assessments were made in the left lateral recumbent position after a 30-minute stabilization period. Sequential measurements were then obtained in the left lateral, right lateral, supine, knee-chest, sitting, and standing positions. Blood samples were analyzed in duplicate for oxygen content on a blood gas analyzer. Statistical analysis was performed by analysis of variance of repeated measures with significance defined at P < or = .05.

RESULTS

There was no significant difference in arterial blood gas or acid base values between any positions in this antepartum population of term healthy women. The composite mean values were as follows: pH 7.46, arterial carbon dioxide pressure (PaCO2) 26.6 mmHg, arterial oxygen pressure 88.3 mmHg, bicarbonate 18.2 mEq/L, saturated arterial hemoglobin level 0.96.

CONCLUSION

Arterial blood gas and acid base values are not altered by maternal position in the late third trimester of pregnancy. The PaO2 in these women studied at moderate altitude was lower than previously reported for healthy pregnant women studied at sea level. Appropriate interpretation of arterial blood specimens of pregnant women should take into account both the pregnancy and altitude at which the women reside.