Mechanical active compression–decompression cardiopulmonary resuscitation (ACD-CPR) versus manual CPR according to pressure of end tidal carbon dioxide (PETCO2) during CPR in out-of-hospital cardiac arrest (OHCA)

AimIn animal and human studies, measuring the pressure of end tidal carbon dioxide (P_ETCO₂) has been shown to be a practical non-invasive method that correlates well with the pulmonary blood flow and cardiac output (CO) generated during cardiopulmonary resuscitation (CPR). This study aims to compare mechanical active compression–decompression (ACD) CPR with standard CPR according to P_ETCO₂ among patients with out-of-hospital cardiac arrest (OHCA), during CPR and with standardised ventilation.MethodsThis prospective, on a cluster level, pseudo-randomised pilot trial took place in the Municipality of Göteborg. During a 2-year period, all patients aged >18 years suffering an out-of-hospital cardiac arrest (OHCA) of presumed cardiac etiology were enrolled. The present analysis included only tracheally intubated patients in whom P_ETCO₂ was measured for 15 min or until the detection of a pulse-giving rhythm.ResultsIn all, 126 patients participated in the evaluation, 64 patients in the mechanical chest compression group and 62 patients in the control group. The group receiving mechanical ACD-CPR obtained the significantly highest P_ETCO₂ values according to the average (p = 0.04), initial (p = 0.01) and minimum (p = 0.01) values. We found no significant difference according to the maximum value between groups.ConclusionIn this hypothesis generating study mechanical ACD-CPR compared with manual CPR generated the highest initial, minimum and average value of P_ETCO₂. Whether these data can be repeated and furthermore be associated with an improved outcome after OHCA need to be confirmed in a large prospective randomised trial.     

Preoperative platelet-rich plasmapheresis and hemodilution with an autotransfusion device in total hip replacement surgery

The effectiveness of both preoperative autologous donation (PAD) and intraoperative autotransfusion (IAT) with an autotransfusion device has recently been questioned. Preoperative apheresis, with separation of concentrated platelet rich-plasma (c-PRP) and erythrocyte concentrate (ERC), represents an aggressive use of the autotransfusion device. Can such a procedure replace PAD in total hip replacement surgery (THR)? Eighty patients undergoing THR were investigated in a prospective and randomized study. Forty patients underwent PAD, and 2 units of ERC + plasma were retrieved within 4 weeks preoperatively. Another 40 patients underwent an immediately preoperative apheresis with a concomitant hemodilution with 4% albumin, retrieving c-PRP (30% of the platelet pool) and 2 units of ERC. Both groups used IAT up to 2 hours postoperatively, with 3% dextran-60 as a plasma substitute according to our standard of care. There were no differences in blood loss, B-hemoglobin or allogeneic transfusions between the groups: 85% of the patients did not receive allogeneic blood. Both apheresis and reinfusion of c-PRP had minor impact on the coagulation parameters. Platelet count increased slightly but significantly (P<0.05) from 154 to 179 x 10(9)/L after the c-PRP at wound closure. Preoperative apheresis with an autotransfusion device, separating platelet-rich plasma and erythrocyte concentrate, is a useful alternative for patients who are unable to utilize the PAD technique for either religious or practical reasons.     

Magnesium in drinking water in relation to morbidity and mortality from acute myocardial infarction

We investigated the importance of magnesium and calcium in drinking water in relation to morbidity and mortality from acute myocardial infarction. Cases were men and women 50-74 years of age living in 18 Swedish municipalities who had suffered an acute myocardial infarction some time between October 1, 1994, and June 30, 1996. Controls were randomly selected from the same study base. We interviewed the surviving cases (N = 823) and controls (N = 853), focusing on risk factors for acute myocardial infarction. We collected individual data on drinking water levels of magnesium and calcium. We classified subjects by quartile of water magnesium or calcium levels. The total number of cases was similar in the four quartiles. The risk of death was 7.6% (95% confidence interval = 2.1-13.1) lower in the quartile with high magnesium levels (> or = 8.3 mg/liter). The odds ratio for death from acute myocardial infarction in relation to water magnesium was 0.64 (95% confidence interval = 0.42-0.97) for the highest quartile relative to the three lower ones. Multivariate analyses showed that other risk factors were not important confounders. For calcium, this study was inconclusive. The data suggest that magnesium in drinking water is associated with lower mortality from acute myocardial infarction, but not with the total incidence.     

Screening for intrauterine growth retardation in late pregnancy

A prospective study was performed on an unselected area-based population in order to improve the antenatal diagnosis of intrauterine growth retardation (IUGR). The clinical importance of simple clinical tests to follow fetal growth (measurements of the symphysis-fundus (SF) distance and recordings of maternal pregnancy weight gain) was investigated. Risk factors for IUGR, appearing in late pregnancy (vaginal bleeding, non-proteinuric pregnancy hypertension and pre-eclampsia) were also studied.

A pathological SF curve (frequency 3.5%) was found to be valuable, but mainly as a screening instrument rather than a diagnostic tool for IUGR. Pre-eclampsia was the only risk factor appearing in late pregnancy that could be associated with IUGR.

Previously we have recommended early pregnancy screening for the following high risk factors for IUGR: smoking, previous birth of a low birth weight infant, low pre-pregnancy weight, renal disease and addiction. When also screening for preeclampsia, 22% of the population exhibited at least one screening factor.

Retrospectively we identified all severely growth-retarded infants (birth weight for gestational age - 2 S.D.) born in 1980 (n = 27). 23 of these infants were delivered to mothers exhibiting high-risk factors for IUGR or a pathological SF curve. In this way a high-risk group for IUGR can be identified, which should be monitored more carefully during the last period of pregnancy.     

Smoking, maternal age, and fetal growth

In a prospective clinical study from an unselected area-based population, the influence on birth weight for gestational age (standardized birth weight) was studied with special respect to risk factors for intrauterine growth retardation. Smoking was the most important risk factor: 16% of the mothers smoked at least ten cigarettes per day, and the influence of smoking on standardized birth weight was highly significant (P less than .001). Maternal age in itself had no effect on standardized birth weight. However, among smokers the reduction in standardized birth weight became more pronounced with increasing maternal age (P less than .001). Longterm smoking has been reported to increase the risk of severe placental complications. This study emphasizes that elderly smokers also must be considered to be at a higher risk than younger smokers for developing fetal growth disturbances.     

Changes in cochlear blood flow during acoustic stimulation as determined by 14C-iodoantipyrine autoradiography

Local blood flow was measured in the tissues of the cochlea using the [14C]iodoantipyrine autoradiographic technique. Flow observed without acoustic stimulation was compared with that seen during exposure to wide-band noise at 85 or 105 dB SPL. Compared with the unexposed cochlea, substantial increases in blood flow were observed during exposure to 85 dB SPL noise in the spiral ganglion, VIII nerve and spiral lamina. Little or no change was noted in external wall structures. These results are consistent with changes in cochlear metabolism which have been reported previously using similar techniques, suggesting that increases in blood flow may be linked to increases in local metabolism. No changes in blood flow were measured during exposure to 105 dB SPL noise. This result is similar to those of other investigators using potentially damaging intensities of acoustic stimulation.     

A prospective controlled five-year follow-up study of primiparas with gestational hypertension

Primiparas with hypertension first recognized in pregnancy and an age- and parity-matched control group, normotensive throughout pregnancy, were monitored during 5-6 years with blood pressure recordings performed in a standardized way. At the end of the study period, 21 out of 49 women with hypertension in pregnancy had developed hypertension requiring therapy or borderline hypertension, compared with 2 women in the control group who had developed borderline hypertension. Therapy was required in 7 of the women. Factors associated with increased risk of developing hypertension were gestational week at diagnosis of gestational hypertension, 1st diastolic blood pressure during follow-up, family history, smoking, and age.     

Anaphylaxis and angioedema due to rubber allergy in children

Delayed hypersensitivity to rubber chemicals is well known but there are an increasing number of case reports on an immediate type of hypersensitivity inducing contact urticaria and anaphylaxis in adults. We now report on three atopic children who developed angioedema, which in two of them progressed to anaphylaxis after exposure to natural rubber products. All three patients showed positive skin prick tests and one had a positive RAST test to latex from the rubber tree (Hevea brasiliensis). It is clear that sensitized subjects are at risk of developing anaphylaxis when exposed to natural rubber products, e.g. during medical examination or surgery when rubber gloves are used.     

Chylothorax as a complication after delivery

A 23-year old female who developed a chylothorax as a probable complication after delivery is described and a possible mechanism is proposed. Conservative treatment was unsuccessful and the surgical management was complicated by an anatomical variation with the thoracic duct presenting as a plexiform system instead of a single duct.