Should families be present during resuscitation?

Weigh the pros and cons of family presence during a crisis, then tell us what you think.     

Is thrombolytic therapy safe during active menstruation?

A 39-year-old female presented to the Emergency Department during the fourth day of menstruation and within 2 hours of the onset of chest pain associated with dyspnea, diaphoresis, and emesis. An electrocardiogram showed acute inferior myocardial infarction and serial CPK enzyme levels peaked at 958 IU/L with 9% MB fraction. Along with aspirin and intravenous nitroglycerin, the patient was given thrombolytic therapy consisting of tPA with an initial bolus of 35 units, followed by 65 units infused within 60 minutes together with heparin 5000 units intravenous bolus, and 1000 units/hour maintenance infusion for 5 days. The menses were prolonged 1 day longer than her usual 5 days; however, there was no increase in the amount of bleeding during any day. The hemoglobin dropped from 12.5 G/dl to 11.3 G/dl in the first 6 hours, but remained stable thereafter. This initial drop in hemoglobin was considered a dilutional effect of 1.5 L of normal saline the patient received intravenously during that period. Although no available guidelines exist regarding the safety of thrombolytic agents during active menstruation, this case report and a few others reported in the literature suggest that normal menstruation is not a contraindication to thrombolytic therapy during acute myocardial infarction.     

Is family presence practical during emergency resuscitation?

When family members ask to be present during the resuscitation of their loved ones, should health care providers grant their requests?     

Does perfluorocarbon deoxygenate during partial liquid ventilation?

Perfluorocarbons accumulate in the dependent regions of the lungs, which may result in regional hypoxia if ventilation with oxygen is insufficient to oxygenate the dependent perfluorocarbon-filled alveoli. In this issue of Critical Care, Max et al present data that demonstrate a decrease in arterial oxygen tension (PaO₂) at 30 min compared to that observed at 5min after administration of FC 3280. These data suggest failure of on-going attributed to the oxygen ventilation/oxygenation to support the initial increase in PaO₂dissolved in the administered perfluorocarbon. Studies such as this one demonstrate that development of the optimal partial liquid ventilation (PLV) technique is ongoing.     

Chemotherapy for gynecological malignancies--a contraindication during pregnancy?

Even though a malignant tumor during pregnancy is very rare it occurs in 0.02-0.1%. With the tendency in society to postpone childbirth to an older age, there will be more cancers diagnosed during pregnancy. The coincidence of malignant disease with pregnancy leads to an enormous emotional burden to the patient, the couple and the medical staff. Surgery for malignant tumors during pregnancy seems to be save. Radiotherapy on the other hand should be avoided. Chemotherapy is regarded to be save during the second and third trimester but it should not be applied during the first trimester because of its teratogenic effects. The most frequent malignant disorders during pregnancy are cervical cancer, breast cancer, melanoma and Hodgkin lymphoma. We discuss possible treatment options for breast cancer and gynecological tumors during pregnancy. Ovarian Cancer is a rare event during pregnancy. Because of frequent prenatal visits most of them are diagnosed at an early stage, with good prognosis. In case of advanced stage of ovarian cancer chemotherapy besides surgery is necessary. The former usually is preferred as monotherapy during pregnancy. To treat breast cancer during pregnancy a mastectomy with axillary lymphonodectomy is necessary to avoid radiotherapy. Indications for chemotherapy are the same as for not pregnant patients. Usually AC with and without 5-FU is used. For invasive cervical cancer surgery or radiotherapy +/- chemotherapy is indicated after induced abortion or cesarean section. Early termination of pregnancy is of no survival benefit to the mother in case of breast cancer and ovarian cancer. In these cases systemic therapy during pregnancy and delivery at 34 weeks is recommended.     

Variability is adaptability…also during weaning!

Heart rate variability in the frequency domain can now be obtained at the bedside in the ICU. Promising data suggest that it may help to characterize a patient response to a spontaneous breathing trial. Refinement of the analysis could even help to predict the outcome of extubation or at least help to detect early patients at risk of failure. It is possible that combining this type of analysis, the breathing pattern variability, and other objective indices could help clinicians in the decision-making process of weaning and extubation.A study by Huang and colleagues [1] in the previous issue of Critical Care suggests that monitoring heart rate variability may be useful during weaning from mechanical ventilation. In ICUs, a spontaneous breathing trial (SBT) is today the recommended test to appreciate whether a patient under mechanical ventilation will tolerate extubation. It is an important step incorporated in the decision-making process for weaning and extubation [2]. During an SBT, the patient is placed in a situation that, for a relatively short period, best simulates what the patient will experience after extubation in terms of the work of breathing [3]. The period of this test constitutes a quasi-‘experimental’ situation during which a careful observation can help clinicians to make the best decision. The test can determine relatively well whether the patient can breathe without ventilatory support, but seems less effective at predicting what will happen after removal of the endotracheal tube. Despite careful approaches, around 15% to 20% of extubated patients will still need to be reintubated in the 72 hours after extubation. These patients have a considerably worse prognosis than those successfully extubated [4].Huang and colleagues proposed an innovative approach to try to take advantage of the natural response of heart rate variability in situations of stress to better predict the risk of extubation failure [1]. Organ function variability seems to be a natural mechanism reflecting the adaptability of the system. In situations of stress, some elements of this variability could reflect the response of the system to constraints and the margins for adaptation. Heart rate and respiratory variability have been studied in many situations but their exact meaning is still far from being fully understood. An index derived from heart rate and from a continuous electrocardiogram analysis would be extremely appealing because this monitoring is available for every patient in the ICU. Analysis of heart rate variability can now be done in terms of frequency domain, which requires fast Fourier transform. Patients with arrhythmias need to be excluded, and the influence of diverse medications interfering with the autonomous system, the sympathovagal balance, or cardiac function is not well known. In different domains, including infections, analysis of heart rate variability has been shown to be a good predictor of the response to stress [5]. In endotoxinemia, this response is independent of fever, for instance [6]. Application of this analysis to weaning is thus attractive. In a carefully performed single-center study, the authors prospectively studied 101 patients submitted to a T-piece trial and measured classic respiratory and cardiovascular indices as well as heart rate variability: 24 patients failed their SBT, and, among the 77 who were extubated, 13 (17%) required reintubation within 72 hours. Variability in terms of very low frequency and total power spectrum were the most interesting pmeters in regard to the analysis of heart rate variability. Their data suggest that (a) a reduced variability in the frequency domain is associated with failure of SBT and (b) in extubated patients, only those with successful extubation are able to increase this heart rate variability after extubation. At the time of the SBT, however, it is not possible to differentiate patients who will ultimately fail extubation among those who tolerate the SBT. These data are promising because they indicate the possibility of an early detection of patients failing the extubation process, independently of any subjective assessment, but are still insufficient at the present time to predict the outcome of extubation. Potentially, such indices could be used to test the potential for adaptation to further stress but this would need further studies.Breathing pattern variability has been similarly explored during weaning from mechanical ventilation, and, interestingly, compble results have already been described [7]. Variability indices were shown to be sufficient to septe success from failure cases during weaning, breathing variability being greater in patients successfully septed from the ventilator and the endotracheal tube. Complex analysis of the breathing pattern suggests that the degree of variability, of autocorrelation between breaths, or of the random fraction of variational activity indicates a different response of the breathing controller to stress and respiratory constraints [8]. During exercise, the patterns of change in heart rate variability, respiratory rate variability, and combined cardiorespiratory variability have been studied simultaneously. Measures of heart rate variability were found to be more frequently able to detect the presence of exercise, with more consistent changes across their metrics compared with breathing variables [9]. However, it is possible that, during a specific situation such as weaning from mechanical ventilation, heart rate variability and breathing pattern variability could be combined in the future to better describe the global response of the cardiorespiratory system and help the clinician in a difficult decision-making process.     

Is enteral feeding tolerated during therapeutic hypothermia?

Objective

To determine whether patients undergoing therapeutic hypothermia following cardiac arrest tolerate early enteral nutrition.

Methods

We undertook a single-centre longitudinal cohort analysis of the tolerance of enteral feeding by 55 patients treated with therapeutic hypothermia following resuscitation from cardiac arrest. The observation period was divided into three phases: (1) 24 h at target temperature (32–34 °C); (2) 24 h rewarming to 36.5 °C; and (3) 24 h maintained at a core temperature below 37.5 °C.

Results

During period 1, patients tolerated a median of 72% (interquartile range (IQR) 68.7%; range 31.3–100%) of administered feed. During period 2 (rewarming phase), a median of 95% (IQR 66.2%; range 33.77–100%) of administered feed was tolerated. During period 3 (normothermia) a median of 100% (IQR 4.75%; range 95.25–100%) of administered feed was tolerated. The highest incidence of vomiting or regurgitation of feed (19% of patients) occurred between 24 and 48 h of therapy.

Conclusions

Patients undergoing therapeutic hypothermia following cardiac arrest may be able to tolerate a substantial proportion of their daily nutritional requirements. It is possible that routine use of prokinetic drugs during this period may increase the success of feed delivery enterally and this could usefully be explored.     

Is ondansetron safe for use during pregnancy?

Question While I usually prescribe doxylamine-pyridoxine for morning sickness, some of my patients with severe nausea and vomiting of pregnancy (NVP) receive ondansetron in hospital. I have read some new precautions recommended by the US Food and Drug Administration (FDA). Is ondansetron safe to use during pregnancy?Answer During the past decade ondansetron has been increasingly used in the United States for NVP, owing to the lack of an FDA-approved drug for this condition. While fetal safety data for doxylamine-pyridoxine are based on more than a quarter of a million pregnancies, the fetal safety data for ondansetron are based on fewer than 200 births. Moreover, a recent case-control study suggested there was an increased risk of cleft palate associated with ondansetron. Recently, the FDA issued a warning about potentially serious QT prolongation and torsade de pointes associated with ondansetron use; the warning included a list of precautions and tests that must be followed. The drug is not labeled for use in NVP in either the United States or Canada. Based on the data available today, ondansetron use cannot be assumed to be safe during pregnancy.     

Heart–lung interactions during neurally adjusted ventilatory assist

Introduction

Assist in unison to the patient’s inspiratory neural effort and feedback-controlled limitation of lung distension with neurally adjusted ventilatory assist (NAVA) may reduce the negative effects of mechanical ventilation on right ventricular function.

Methods

Heart–lung interaction was evaluated in 10 intubated patients with impaired cardiac function using esophageal balloons, pulmonary artery catheters and echocardiography. Adequate NAVA level identified by a titration procedure to breathing pattern (NAVAal), 50% NAVAal, and 200% NAVAal and adequate pressure support (PSVal, defined clinically), 50% PSVal, and 150% PSVal were implemented at constant positive end-expiratory pressure for 20 minutes each.

Results

NAVAal was 3.1 ± 1.1cmH₂O/μV and PSVal was 17 ± 2 cmH₂0. For all NAVA levels negative esophageal pressure deflections were observed during inspiration whereas this pattern was reversed during PSVal and PSVhigh. As compared to expiration, inspiratory right ventricular outflow tract velocity time integral (surrogating stroke volume) was 103 ± 4%, 109 ± 5%, and 100 ± 4% for NAVAlow, NAVAal, and NAVAhigh and 101 ± 3%, 89 ± 6%, and 83 ± 9% for PSVlow, PSVal, and PSVhigh, respectively (p < 0.001 level-mode interaction, ANOVA). Right ventricular systolic isovolumetric pressure increased from 11.0 ± 4.6 mmHg at PSVlow to 14.0 ± 4.6 mmHg at PSVhigh but remained unchanged (11.5 ± 4.7 mmHg (NAVAlow) and 10.8 ± 4.2 mmHg (NAVAhigh), level-mode interaction p = 0.005). Both indicate progressive right ventricular outflow impedance with increasing pressure support ventilation (PSV), but no change with increasing NAVA level.

Conclusions

Right ventricular performance is less impaired during NAVA compared to PSV as used in this study. Proposed mechanisms are preservation of cyclic intrathoracic pressure changes characteristic of spontaneous breathing and limitation of right-ventricular outflow impedance during inspiration, regardless of the NAVA level.

Trial registration

Clinicaltrials.gov Identifier: {"type":"clinical-trial","attrs":{"text":"NCT00647361","term_id":"NCT00647361"}}NCT00647361, registered 19 March 2008

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-014-0499-8) contains supplementary material, which is available to authorized users.     

Beta‐globin mRNA increases rapidly during erythropoietin treatment

Recombinant human erythropoietin (r‐HuEpo) has an important role in the treatment of anaemic patients. Because of the high cost of r‐HuEpo treatment, an early indicator of whether a patient is responding to the therapy would be valuable. Although measurement of gene expression is a promising new tool, it has not yet been established in clinical practice. The response pattern of a possible new marker, β‐globin mRNA, is compared with reticulocyte count, levels of haemoglobin, transferrin receptor and ferritin after r‐HuEpo treatment. Eight healthy volunteers were stimulated with erythropoietin three times a week for four weeks and compared with five untreated control subjects. Blood samples were collected before each erythropoietin injection. Quantitative measurement of β‐globin mRNA was performed by poly(A) selection onto a manifold plastic support, coated with oligo(dT). The mRNA was reverse transcribed, followed by quantitative analysis using PCR via the 5′ nuclease assay. The individuals treated with rHuEpo showed a more distinct increase in β‐globin mRNA levels than all other laboratory measurements. β‐globin mRNA levels are therefore promising as a marker for the response to treatment with Epo.