Effect of sequential coronary artery bypass venous grafting on right ventricular functions assessed by tissue Doppler echocardiography

Background

Coronary artery bypass graft surgery is a well-known and proven method of treatment for coronary artery disease. A modification of this method is complete revascularisation of the right ventricle by sequential bypass grafting of the right coronary artery, the effects of which on ventricular function need to be clarified. We sought to determine the effect of the sequential bypass graft method on right ventricular (RV) function utilising tissue Doppler echocardiography.

Methods

A total of 35 coronary artery disease patients (group A: 20 sequential grafts; group B: 15 individual grafts) were enrolled. Patients were examined pre-operatively with tissue Doppler echocardiography for RV function, and again postoperatively after the first month.

Results

Pre-operatively, there were no significant differences with regard to demographics or basal echocardiographic findings. On the other hand, postoperative right ventricular diastolic function was found to have improved significantly as the right ventricular E wave and E/A increased (9.5 ± 1.6 vs 7.6 ± 2.7 cm/s, p = 0.009 and 1.4 ± 0.2 vs 0.9 ± 0.2, p ≤ 0.01, respectively), while the A wave and isovolumic relaxation times (6.8 ± 2.1 vs 8.3 ± 3.4 cm/s, p < 0.03 and 55.2 ± 11.9 vs 87.2 ± 16.2 ms, p < 0.001, respectively) decreased. Although the S-wave peak amplitude decreased in group A patients, it did not reach statistical significance.

Conclusions

Sequential, but not single, complete revascularisation of the right coronary artery appeared to improve the diastolic function of the right ventricle.

Theoretical investigations of α,α,α-trifluoro-3, -p and o-nitrotoluene by means of density functional theory

This study reports the optimized molecular structures, vibrational frequencies including Infrared intensities and Raman activities, corresponding vibrational assignments, (1)H and (13)C NMR chemical shifts, the magnitudes of the JCH and JCC coupling constants, Ultraviolet-visible (UV-vis) spectra, thermodynamic properties and atomic charges of the title compounds, α,α,α-trifluoro-3, -p and o-nitrotoluene, in the ground state by means of the density functional theory (DFT) with the standard B3LYP/6-311++G(d,p) method and basis set combination for the first time. Theoretical vibrational spectra were interpreted by normal coordinate analysis based on scaled density functional force field. The results show that the vibrational frequencies and chemical shifts calculated were obtained to be in good agreement with the experimental data. Based on the comparison between experimental results and theoretical data, the calculation level chosen is powerful approach for understanding the identification of all the molecules studied. In addition, not only were frontier molecular orbitals (HOMO and LUMO), molecular electrostatic potential (MEP) and electrostatic potential (ESP) simulated but also the dipole moment, softness, electronegativity, chemical hardness, electrophilicity index, transition state and energy band gap values were predicted. According to the investigations, all compounds were found to be useful to bond metallically and interact intermolecularly; however, the thermodynamic properties confirm that the α,α,α-trifluoro-p-nitrotoluene was more reactive and more polar than the others.

Testicular versus epididymal spermatozoa in intracytoplasmic sperm injection treatment cycles

BACKGROUND

Normal fertilization and ongoing pregnancy can be achieved using intracytoplasmic sperm injection (ICSI), even with severely immature spermatozoa. However, the published literature documents conflicting results as to the outcome of ICSI.

METHODS

Surgical extraction of spermatozoa in 111 ICSI treatment cycles performed over five years at the Assisted Conception Unit (ACU), University College Hospital (UCH), was retrospectively evaluated to compare the outcome of ICSI treatment using either testicular or epididymal spermatozoa.

RESULTS

A higher normal fertilization rate and lower abnormal fertilization rate was observed in the epididymal spermatozoa group than in the testicular spermatozoa group. Embryo development on day 3 after fertilization and implantation was significantly better in the epididymal spermatozoa group. Clinical and ongoing pregnancy rates were higher and the spontaneous miscarriage rate lower in the epididymal spermatozoa group, but only the clinical pregnancy rate reached statistical significance.

CONCLUSIONS

The origin of surgically extracted spermatozoa has an effect on the success of assisted reproduction using ICSI, and the immaturity of testicular spermatozoa may affect fertilization, embryo development, implantation and pregnancy.

Is there any relationship between serum and urine neopterin and serum interferon-gamma levels in the activity of Behcet's disease?

BACKGROUND

Behcet's disease (BD) is a chronic, inflammatory, multisystem vasculitic disorder. There is no reliable laboratory marker that indicates disease activity. Neopterin is an immunological marker of cellular immune activation, which is secreted by monocytes/macrophages as a result of interferon-gamma (IFN-gamma) secretion by activated T lymphocytes.

OBJECTIVE

We aimed to investigate serum and urine neopterin levels in BD patients.

METHODS

Forty-five patients who were diagnosed according to the criteria of the International Study Group for BD and 45 age- and sex-matched healthy controls were enrolled in the study. Disease activity was considered by clinical findings. Serum and urine neopterin levels and serum IFN-gamma levels were measured.

RESULTS

The mean values of serum and urine neopterin levels were 12.68 +/- 4.87 nmol/L and 167.53 +/- 148.73 micromol/mol creatinine, respectively, in BD patients (P = 0.000 and P = 0.008, respectively), which were statistically significantly different from the control group. However, there was no significant statistical difference between serum and urine neopterin levels of the clinically active and inactive patients. It was also found that the mean value of serum IFN-gamma levels was higher in healthy controls than in BD patients (P = 0.000).

CONCLUSIONS

We conclude that serum and urinary neopterin measurement can not be used as a reliable laboratory marker as the BD patients' serum and urinary neopterin levels do not increase in the active stage even though these levels increase when compared to healthy controls.

L-myc gene polymorphism and risk of thyroid cancer

L-myc gene polymorphism is a representative genetic trait responsible for an individual's susceptibility to several cancers. However, there have been no reports concerning the association between thyroid cancer and L-myc gene polymorphism.

AIM

To analyze the distribution of L-myc gene polymorphism in Turkish patients with thyroid disorders and thyroid cancers.

METHODS

We used a molecular genotyping method, polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP). We studied 138 patients of whom 47 had multinodular goiter, 13 had follicular cancer and 69 had papillar cancer, in comparison with control group of 109 healthy individuals.

RESULTS

No significant difference in the distribution of genotypes was observed between thyroid patients and controls. Carrying SS or LS genotype revealed a 1.96-fold (95% CI 0.573-6.706) risk for the occurrence of follicular cancer when compared with controls, and 3.11-fold (95% CI 0.952-10.216), when compared with multinodular goiter patients (p=0.04).

CONCLUSION

We suggest that L-myc genotype profiling together with other susceptibility factors, may be useful in the screening for thyroid nodular malignancy.

Pneumosinus dilatans of the ethmoid sinus presenting with exophthalmus: a case report and review of the literature

Pneumosinus dilatans (PSD) is a rare condition of unknown aetiology in which there is enlargement of the paranasal sinuses by air, where the affected sinus expands beyond the normal boundaries of bone without thinning of its bony walls. The case of a 28 year old male with PSD, who had gradually increasing exophthalmus and diplopia, is presented and characteristics of this condition are reviewed with literature data.

Rare clinical presentation of nonobstructive hypertrophic cardiomyopathy: Apical aneurysm with thrombus

Hypertrophic cardiomyopathy patients rarely have left ventricular apical aneurysms without coronary artery disease and the pathophysiological processes responsible for apical wall thinning and aneurysm formation are not known exactly today. Here we present a rare nonobstructive hypertrophic cardiomyopathy case with an apical thrombotic aneurysm.

Relationship between male reproductive hormones, sperm DNA damage and markers of oxidative stress in infertility

This study investigated the relationship between male reproductive hormones and sperm DNA damage and markers of oxidative stress in men undergoing infertility evaluation for male factor (n = 66) and non-male factor (n = 63) infertility. Semen samples were analysed for DNA fragmentation index (DFI). Serum samples were analysed for FSH, inhibin B, anti-Müllerian hormone (AMH), testosterone and total antioxidant capacity (TAC). Serum inhibin B was significantly lower in the male factor group compared with the non-male factor group. Inhibin B showed a positive correlation with sperm concentration and motility, and serum AMH showed a positive correlation with sperm concentration and semen volume. DFI was 3-fold higher in the male factor group and showed a negative correlation with sperm motility. Blood plasma TAC was negatively related to sperm concentration. The results confirm that AMH and inhibin B are markers of Sertoli cell function. Sperm DNA damage is moderately increased in male factor infertility, and is negatively associated with sperm motility. A negative association between antioxidant activity and sperm concentration suggests that even minimal oxidative stress may influence sperm concentration. However, there was no significant relationship between hormone concentrations, sperm DNA damage and total antioxidant capacity, suggesting other mechanisms for sperm dysfunction.

Unusual case of laryngeal tumor (capillary hemangioma) obturating the larynx

OBJECTIVES

Capillary hemangioma isolated to the free edge of the vocal fold is a rare clinical finding. We see many young patients, mostly infants under a year, who are having surgical intervention for laryngeal hemangiomas. A rapid proliferative phase occurs during the first 9 to 12 months of life; this followed by an involution phase that may be completed by 3 to 5 years of age, but can last up to 12 years.

MATERIAL AND METHODS

We report the case of a 15-year-old boy who had hoarseness for a two-year related to a laryngeal mass which growth pattern was unknown.

RESULTS

On endoscopic examination a polypoid mass, which was diagnosed as a capillary hemangioma later, appeared on the left vocal fold. The lesion was excised with cold-knife instrumentation by using mini-flap technique.

CONCLUSION

The clinical and histopathological features and therapeutic options are discussed.

Does topical lidocaine with adrenaline have an effect on morbidity in pediatric tonsillectomy?

OBJECTIVE

To evaluate the efficacy of lidocaine with adrenaline on post-operative morbidity in pediatric patients after tonsillectomy.

STUDY DESIGN

A double blind prospective randomized controlled clinical study.

METHODS

The study is consisting of two groups of pediatric patients following tonsillectomy performed in a university hospital. One group received lidocaine with adrenaline soaked swabs packed in their tonsillar fossae while the control group received saline-soaked swabs. Chi-square and two-tailed unpaired Student's t-tests were used to compare the two independent groups. p<0.05 was accepted as statistically significant.

RESULTS

No significant pain-relieving effect was seen in the lidocaine with adrenaline group (p>0.05) and also the other post-operative parameters such as nausea, fever, vomiting, odor, bleeding, otalgia and trismus were not statistically different between the two groups based on chi-square analysis (p>0.05). There were no complications associated with lidocaine and adrenaline.

CONCLUSION

We suggest that application of topical lidocaine with adrenaline seems to be a safe and easy medication for local anesthetic use. However, in our study, lidocaine with adrenaline offered no advantage over placebo in the control of post-operative pain and other morbidity related factors following pediatric tonsillectomy. We therefore do not recommend topical application of lidocaine with adrenaline for reducing morbidity in pediatric tonsil surgery.

Thermal decomposition of generation-4 polyamidoamine dendrimer films: decomposition catalyzed by dendrimer-encapsulated Pt particles

The thermal decomposition of hydroxyl-terminated generation-4 polyamidoamine dendrimer (G4OH) films deposited on Au surfaces has been compared with decomposition of the same dendrimer encapsulating an approximately 40-atom Pt particle (Pt-G4OH). Infrared absorption reflection spectroscopy studies showed that, when the films were heated in air to various temperatures up to 275 degrees C, the disappearance of the amide vibrational modes occurred at lower temperature for the Pt-G4OH film. Dendrimer decomposition was also investigated by thermogravimetric analysis (TGA) in both air and argon atmospheres. For the G4OH dendrimer, complete decomposition was achieved in air at 500 degrees C, while decomposition of the Pt-G4OH dendrimer was completed at 400 degrees C, leaving only platinum metal behind. In a nonoxidizing argon atmosphere, a greater fraction of the G4OH decomposed below 300 degrees C, but all of the dendrimer fragments were not removed until heating above 550 degrees C. In contrast, Pt-G4OH decomposition in argon was similar to that in air, except that decomposition occurred at temperatures approximately 15 degrees C higher. Thermal decomposition of the dendrimer films on Au surfaces was also studied by temperature programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS) under ultrahigh vacuum conditions. Heating the G4OH films to 250 degrees C during the TPD experiment induced the desorption of large dendrimer fragments at 55, 72, 84, 97, 127, 146, and 261 amu. For the Pt-G4OH films, mass fragments above 98 amu were not observed at any temperature, but much greater intensities for H(2) desorption were detected compared to that of the G4OH film. XPS studies of the G4OH films demonstrated that significant bond breaking in the dendrimer did not occur until temperatures above 250 degrees C and heating to 450 degrees C caused dissociation of C=O, C-O, and C-N bonds. For the Pt-G4OH dendrimer films, carbon-oxygen and carbon-nitrogen bond scission was observed at room temperature, and further decomposition to atomic species occurred after heating to 450 degrees C. All of these results are consistent with the fact that the Pt particles inside the G4OH dendrimer catalyze thermal decomposition, allowing dendrimer decomposition to occur at lower temperatures. However, the Pt particles also catalyze bond scission within the dendrimer fragments so that decomposition of the dendrimer to gaseous hydrogen is the dominant reaction pathway compared to desorption of the larger dendrimer fragments observed in the absence of Pt particles.

Semen quality before and after gonadotoxic treatment

BACKGROUND

The aim of this study was to analyse the semen quality of patients before and after gonadotoxic therapy.

PATIENTS AND METHODS

We evaluated semen quality in 314 patients over a 26 year period. The diagnostic categories were leukaemia (n = 13); lymphoma (n = 128); testicular cancer (n = 102); benign conditions (n = 13); and other malignant neoplasms (n = 58). The degree of azoospermia or oligozoospermia for each disease category was recorded. We then analysed the recovery in semen quality over time for each disease category.

RESULTS

The mean patient age was 27.9 years (range 13-65 years). A total of 1115 post-treatment semen samples were analysed from 314 patients. There was a significant reduction in the post-treatment sperm concentration, sperm motility and semen volume compared with pre-treatment levels (P < 0.05) in the entire cohort. However, the sperm movement and motility grade remained unaffected. Patients with testicular carcinoma had the lowest pre-treatment sperm concentrations but also the lowest incidence of azoospermia after cancer treatment. Patients with lymphoma and leukaemia had the highest incidence of post-treatment azoospermia and oligospermia. Patients having the largest reductions in their sperm concentration after treatment required the longest recovery period for spermatogenesis. The diagnostic category was the only significant predictor of post-treatment azoospermia.

CONCLUSION

Gonadotoxic treatment results in a significant reduction in sperm quality. The type of cancer or disease, and the pre-treatment sperm concentrations were found to be the most significant factors governing post-treatment semen quality and recovery of spermatogenesis. All categories of patients displayed varying degrees of azoospermia and oligozoospermia, and recovery of gonadal function from these states was not significant. This highlights the importance of ensuring sperm banking before treatment, including for patients with benign conditions. Several factors and associations are discussed further in order to give an insight into the pre- and post-gonadotoxic treatment effects.

Nasopharyngeal aerobic bacterial flora and Staphylococcus aureus nasal carriage in deaf children

OBJECTIVE

To determine the nasopharyngeal aerobic bacterial flora and Staphylococcus aureus nasal carriage in deaf children and the role of flora in deafness.

STUDY DESIGN

A prospective, controlled study.

METHODS

Nasopharyngeal and nasal swabs were collected from 87 deaf children with acquired etiology at Zonguldak primary school for the deaf and 56 healthy children. The children with genetic base (syndromic or nonsyndromic, familial or sporadic, AD, AR or X-linked recessive), and also with the history of drug exposure, head trauma, birth trauma, prematurity, hyperbilirubinemia and the viral diseases with high fever (like mumps and measles) were excluded from the study. Swabs were inoculated on to a variety of bacteriological culture media, which were then incubated in an appropriate atmosphere. Colonisation of Group A beta hemolytic streptococcus, Streptococcus pneumoniae, Haemophilus influenzae, Neisseria menengitidis, Moraxella catarrhalis and S. aureus in upper respiratory tract were investigated. Antimicrobial susceptibility testing of the isolates were determined according to National committee for clinical laboratory standards (NCCLS) guidelines.

RESULTS

Although, the rates of colonization of the nasopharyngeal aerobic bacteria and nasal S. aureus did not differ significantly between deaf children and normal healthy subjects, less colonization rates were found in deaf children than normal healthy subjects. S. aureus was isolated from 18 (20.7%) deaf children. All S. aureus isolates from deaf children were susceptible to oxacillin. Penicillin susceptibility rate was 22.2%.

CONCLUSION

It is considered that nasopharyngeal and nasal colonizations of deaf children with potentially pathogenic aerobic bacterial flora is not a significant risk factor for acquired infections when compared with healthy children.

Number of embryos for transfer following in-vitro fertilisation or intra-cytoplasmic sperm injection

BACKGROUND

The traditional reliance on the transfer of multiple embryos during in vitro fertilisation (IVF) in order to maximise the chance of pregnancy, has resulted in increasing rates of multiple pregnancies. Women undergoing IVF had a 20 - fold increased risk of twins and 400 - fold increased risk of higher order pregnancies (Martin 1998). The maternal and perinatal morbidity and mortality as well as national health service costs associated with multiple pregnancies is significantly high in comparison with singleton births (Luke 1992; Callahan 1994; Goldfarb 1996). Single embryo transfer is now being considered as an effective means of reducing this iatrogenic complication. This systematic review evaluates the effectiveness of elective two embryo transfer in comparison with single and more than two embryo transfer following IVF and ICSI (intra cytoplasmic sperm injection) treatment.

OBJECTIVES

The aim of this review is to determine, whether in couples who undergo IVF/ICSI: (1) the elective transfer of two embryos improves the probability of livebirth compared with: (a) Single embryo transfer, (b) Three embryo transfer or (c) Four embryo transfer.(2) the elective transfer of three embryos improves the probability of livebirth compared with: (a) Single embryo transfer, or (b) Four embryo transfer,

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders and Subfertility Group's trials register (searched June 2003), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 4, 2003), MEDLINE (1970 to 2003), EMBASE (1985 to 2003) and reference lists of articles. We also handsearched relevant conference proceedings and contacted researchers in the field.

SELECTION CRITERIA

Only randomised controlled trials were included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed eligibility and quality of trials.

MAIN RESULTS

We found no studies that compared a policy of transferring multiple embryos on one cycle versus a policy of cryo- preservation and transfer of a single embryo over multiple cycles. We also found no trials comparing transfer of two versus three embryos. Three small, poorly reported trials compared transfer of two versus one embryo in a single cycle, and one small, poorly reported trial compared transfer of two versus four embryos in a single cycle. The clinical pregnancy rate per woman/couple associated with two embryo transfer was significantly higher compared to single embryo transfer (OR 2.08, 95% CI 1.24 to 3.50; test for overall effect p = 0.006). The live birth rate per woman/couple associated with two embryo transfer was also significantly higher than that associated with single embryo transfer (OR 1.90, 95% CI 1.12 to 3.22, test for overall effect p=0.02). The multiple pregnancy rate was significantly lower in women who had single embryo transfer (OR 9.97, 95% CI 2.61 to 38.19; p = 0.0008). The effectiveness of double embryo transfer versus four embryo transfer was tested in a single trial. There was no statistically significant differences in the clinical pregnancy rate (OR 0.75, 95% CI 0.26 to 2.16; p=0.6), and multiple pregnancy rates (OR 0.44. 95% CI 0.10 to 1.97; p = 0.28) between the two groups. The livebirth rate in the four embryo transfer group was higher compared to the two embryo transfer group, but the results were not statistically significant (OR 0.35, 95% CI 0.11 to 1.05; p = 0.06).

REVIEWERS' CONCLUSIONS

The results of this systematic review suggest that live birth and pregnancy rates following single embryo transfer are lower than those following double embryo transfer as are the chances of multiple pregnancy including twins. As such, it is unlikely that the conclusions are robust enough to catalyse a change in clinical practice. The studies included are limited by their small sample size, so that even large differences might be hidden. Cumulative livebirth rates are seldom reported. The data were inadequate to draw conclusions about single embryo transfer and first frozen single embryo transfer (1FZET) or subsequent single frozen embryo transfers. Until more evidence is available single embryo transfer may not be the preferred choice for all patients undergoing IVF/ICSI. Clinicians may need to individualise protocols for couples based on their risks of multiple pregnancy. A definitive pragmatic, large multi centre randomised controlled trial comparing single embryo versus double embryo transfer in terms of clinical and cost effectiveness as well as acceptability is required. The primary outcome measured should be cumulative livebirth per woman/couple.

Can post-adenotonsillectomy morbidity be reduced by intravenous 24 h hydration in pediatric patients following adenotonsillectomy?

OBJECTIVE

To determine the benefit of 24 h intravenous hydration for pediatric postoperative adenotonsillectomy patients.

STUDY DESIGN

A prospective, randomized controlled clinical study.

METHODS

The study is consisting of two groups of pediatric patients following adenotonsillectomy performed in a university hospital. One group received 24 h IV hydration at hospital while the other did not have IV hydration. Chi-square and two-tailed unpaired Student's t-tests were used to compare the two independent groups. P < 0.05 was accepted as statistically significant.

RESULTS

Although the postoperative parameters such as nausea, fever, vomiting, odor, bleeding, otalgia and trismus were not statistically different between the two groups based on chi-square analysis (P > 0.05), a significant pain-relieving effect was seen in hydration group after the second day (P < 0.05). There were no complications associated with intravenous hydration.

CONCLUSION

Results of the current study suggest that 24 h IV hydration can reduce postoperative pain in late postoperative period following adenotonsillectomy in children but does not offer much advantage over without IV hydration therapy based on a number of other parameters. Furthermore, it seems to be cost effective, safe and easy and even these are encouraging for further studies in the future.

Novel PDE5 inhibitors for the treatment of male erectile dysfunction

Erectile dysfunction (ED) affects the lives of approximately 150 million men worldwide. ED may be a cause of male sub-fertility in a significant proportion of patients. There is now an expanding armamentarium for the management of ED, including oral agents such as phosphodiesterase type 5 (PDE5) inhibitors. PDE5 inhibitors may also be useful in situations of temporary ED in couples undergoing IVF. Two novel PDE5 inhibitors have been commercially launched in the European Union in the first quarter of 2003. This article reviews the pharmacology and clinical efficacy of these new agents and their potential role in treating patients with male sub-fertility.

Aspirin dilemma. Remodelling the hypothesis from a fertility perspective

Many clinical trials in obstetrics have failed to demonstrate improved outcomes with low-dose aspirin. This is not entirely surprising as prescribing aspirin for compromised tissue perfusion without insight into underlying pathology inevitably leads to suboptimal outcomes. We argue that a mismatch between the aspirin dose and the underlying pathology of altered tissue perfusion is the key factor to this failure. Based on this groundwork, we address the question of how best to optimize the dose of aspirin for use in fertility management, by providing examples from the assisted conception and recurrent miscarriage settings.

Fetal antecedents of male factor sub-fertility: how important is birthweight?

BACKGROUND

Severely reduced fetal growth has been linked to gonadal dysfunction. The aim of this study was to explore the link between birthweight and subsequent male infertility using the Aberdeen Maternity and Neonatal Databank (AMND).

METHODS AND RESULTS

Assuming 80% power at the 5% significance level, a minimum of 126 men (63 in each group) was required to show a mean difference of 0.5 (SD = 1) in the standardized birthweight scores between cases and controls. Men born locally with unexplained male factor infertility (n = 79) were identified from the infertility clinic database. Men with normal semen parameters, born in Aberdeen and attending the infertility clinic with their partners (n = 104), served as controls. The pregnancy records of these men's mothers were obtained from the AMND and a standard case-control analysis performed. In addition to standardized birthweight scores, the following variables were studied: crude birthweight, social class, maternal age, parity, obstetric history, antepartum and peripartum events.

CONCLUSIONS

No differences were found between the two groups, suggesting that low birthweight is unlikely to affect male fertility in later life.

Avoiding multiple pregnancies in ART: evaluation and implementation of new strategies

Strategies for reducing the multiple pregnancies which increase perinatal mortality and morbidity in women undergoing IVF are discussed. Elective single embryo transfer with the promise of subsequent transfer of frozen-thawed embryos would achieve the goal of a single healthy child as a result of IVF treatment. The urgent establishment of a definitive trial comparing elective single versus double embryo transfer is advocated.

Circulatory responses to maternal hyperoxaemia and hypoxaemia assessed non-invasively in fetal sheep at 0.3-0.5 gestation in acute experiments

OBJECTIVES

To determine fetal haemodynamic responses to hyperoxaemia and hypoxaemia in early pregnancy.

DESIGN

Repeated measurements in acute experiments.

SETTING

Experimental physiology laboratory.

METHODS

Non-invasive Doppler ultrasound of the umbilical vein, ductus venosus, umbilical and common carotid arteries of 12 fetal lambs (0.27-0.56 gestation) during maternal hyperoxaemia and hypoxaemia under ketamine anaesthesia. The effect of gestational age, hyperoxaemia, and hypoxaemia were assessed based on analysis of variance for dependent measurements and P < or = 0.05 was considered significant. Differences between groups were considered significant if the 95% confidence interval did not include zero.

RESULTS

Gestational age had a significant effect on the blood velocity in the umbilical vein and ductus venosus. There were no circulatory changes during hyperoxaemia, but a simultaneous increase of pCO2 was an important confounder. However, hypoxaemia caused significantly reduced heart rate, reduced maximum and weighted mean blood velocity, and augmented pulsation in the umbilical vein. Hypoxaemia also caused reduced velocities in the ductus venosus (peak velocity during systole and minimum during diastole, and time-averaged velocity) and augmented pulsation of the flow velocity. Additionally, the pulsatility of blood flow increased in the umbilical artery and was reduced in the common carotid artery.

CONCLUSIONS

Maternal hypoxaemia in early pregnancy causes similar fetal circulatory responses to those in late pregnancy: bradycardia, reduced venous flow velocities, augmented pulsatility in veins and a redistributional flow velocity pattern of the umbilical and common carotid arteries.

Amniotic gas values and acid-base status during acute maternal hyperoxemia and hypoxemia in the early fetal sheep

OBJECTIVE

This study was undertaken to determine amniotic fluid gas values and acid-base balance during maternal hyperoxemia and hypoxemia in early pregnancy.

STUDY DESIGN

Anesthetized sheep (n = 12) in early and mid pregnancy (0.3 to 0.5 gestation) were subjected to hyperoxemia followed by hypoxemia. Amniotic fluid PO (2), pH, PCO (2), bicarbonate concentration, and base excess were monitored continuously with a multiparameter Paratrend (Diametrics Medical Inc, St Paul, Minn) sensor and compared between 0.3 and 0.5 gestation.

RESULTS

During maternal normoxemia all parameters were constant. At all gestational ages maternal hyperoxemia caused no changes apart from a rapid increase in amniotic fluid PO (2) (P <.001). Maternal hypoxemia led to a reduced amniotic fluid PO (2) (P <.001), whereas the PCO (2) and the bicarbonate concentration increased (P <.001). Changes in amniotic fluid gas values and acid-base balance were more pronounced at 0.3 gestation than at 0.5 gestation. Amniotic fluid Po(2) responded earlier to maternal hyperoxemia than to hypoxemia (9. 5 vs 14.3 minutes; P <.001). During hypoxemia maternal PaCO (2) changed faster than did amniotic fluid PCO (2) (P <.001).

CONCLUSIONS

Acute maternal hypoxemia during early pregnancy was quickly reflected in amniotic fluid gas values and acid-base balance, whereas hyperoxygenation induced the quickest changes in amniotic fluid PO (2). The metabolic effects of maternal hyperoxemia and hypoxemia were also more pronounced during early pregnancy than at mid pregnancy.

In-vivo measurement of intrauterine gases and acid-base values early in human pregnancy

A new multiparameter sensor that combines electrochemical and fibre-optic technology was used for continuous in-vivo investigation of pH, carbon dioxide partial pressure (PCO(2)), oxygen partial pressure (PO(2)), bicarbonate concentration (HCO(3)(-)), base excess, and oxygen saturation (O(2)Sat) early in human pregnancy. The sensor was inserted into the amniotic cavity and the placental bed of 16 pregnancies at 10-15 weeks gestation, before termination under general anaesthesia. Amniotic fluid and retroplacental blood from the same site were also aspirated and analysed by means of cartridges and a portable blood gas analyser. Eleven series of measurements were obtained. The variation in measurements over the 5 min of monitoring was </=10% for all parameters. The sensor was damaged during insertion into the amniotic cavity in one case and in the placental bed in four cases. Measurements of PO(2) in both the amniotic cavity and the placental bed and of pH in the placental bed were higher using the cartridges than in vivo. The results indicated that in-vivo monitoring of fetoplacental gas and acid-base with a sensor is stable and accurate. Such technology will be helpful in improving our understanding of the fetoplacental metabolism in normal and complicated pregnancies.

Transesophageal echocardiography in cardiac surgical emergencies

The value and utility of transesophageal echocardiography (TEE) in unstable cardiac surgical patients have been assessed; 119 TEE studies were performed and evaluated in the emergency setting. The studies were performed in the cardiac surgical intensive care unit (n = 62) and in the operating room (n = 57). There were 81 men and 38 women with a mean age of 58.2 years. The indications for TEE were as follows: hypotension refractory to conventional treatment (n = 83); prosthetic or native valve dysfunction (n = 25); and suspected aortic dissection (n = 10). TEE provided valuable diagnostic information in 107 patients and was completely normal in 12 patients. Based on these results 22 patients had urgent surgical intervention without further studies. The average time to diagnosis was 11.2 minutes. No significant complications were noted. Our results suggest that TEE is highly diagnostic for most of the abnormalities responsible for hemodynamic instability in the perioperative period and facilitates decision making in cardiac surgical emergencies.