History of blood pressure measurement in newborns and infants

The development of methods for measuring blood pressure (BP) in newborns and small children has a rich history. Methods for BP measuring in adults had to be adapted to this age group. For measuring BP in direct invasive way, a suitable approach had to be found to access the arterial circulation through the umbilical and later radialis artery. Currently, results obtained from direct invasive BP measurement are considered the "gold standard". The development of non-invasive methods for BP measuring in newborns and children began with the use of von Basch's sphygmomanometer (1880). In 1899, Gustav Gärtner constructed the device, which was the basis for the flush method. After the discovery of the palpation and auscultation methods, these methods were also used for BP measurement in newborns and children, however, the BP values obtained in these ways were typically underestimated using excessively wide cuffs. From the auscultation method, methods utilizing ultrasound and infrasound to detect arterial wall movement and blood flow were later developed. The oscillometric method for BP measurement was introduced by E. J. Marey so early as in 1876. In 1912, P. Balard used the oscillometric technique to measure blood pressure in a large group of newborns. Through different types of oscillometers using various methods for detecting vascular oscillations (such as xylol method, impedance and volume plethysmography, etc.), the development has continued to assessment of vascular oscillations by modern sensor technology and software. For continuous non-invasive blood pressure measurement, the volume-clamp method, first described by Jan Peňáz in 1968, was developed. After modification for use in newborns, application of the cuff to the wrist instead of the finger, it is primarily used in clinical physiological studies to evaluate beat-to-beat BP and heart rate pressure variability, such as in the determination of the baroreflex sensitivity.

Mechanisms of Cardiovascular Changes of Phototherapy in Newborns with Hyperbilirubinemia

During phototherapy of jaundiced newborns, vasodilation occurs in the skin circulation compensated by vasoconstriction in the renal and mesenteric circulation. Furthermore, there is a slight decrease in cardiac systolic volume, and blood pressure, as well as an increase in heart rate and discrete changes in the heart rate variability (HRV). The primary change during phototherapy is the skin vasodilation mediated by multiple mechanisms: 1) Passive vasodilation induced by direct skin heating effect of the body surface and subcutaneous blood vessels, modified by myogenic autoregulation. 2) Active vasodilation mediated via the mechanism provided by axon reflexes through nerve C-fibers and humoral mechanism via nitric oxide (NO) and endothelin 1 (ET-1). During and after phototherapy is a rise in the NO:ET-1 ratio. 3) Regulation of the skin circulation through the sympathetic nerves is unique, but their role in skin vasodilation during phototherapy was not studied. 4) Special mechanism is a photorelaxation independent of the skin heating. Melanopsin (opsin 4) - is thought to play a major role in systemic vascular photorelaxation. Signalling cascade of the photorelaxation is specific, independent of endothelium and NO. The increased skin blood flow during phototherapy is enabled by the restriction of blood flow in the renal and mesenteric circulation. An increase in heart rate indicates activation of the sympathetic system as is seen in the measures of the HRV. High-pressure, as well as low-pressure baroreflexes, may play important role in these adaptation responses. The integrated complex and specific mechanism responsible for the hemodynamic changes during phototherapy confirm adequate and functioning regulation of the neonatal cardiovascular system, including baroreflexes.

Investigation of association between genetic polymorphisms of MMP2, MMP8, MMP9 and TIMP2 and development of varicose veins in the Slovak Population - pilot study

Matrix metalloproteinases (MMPs) are a family of zinc-dependent metalloendopeptidases that degrades extracellular matrix (ECM) components. MMPs are associated with venous wall remodelling, proliferation, migration, phenotypic and functional transformation of vascular smooth muscle cells and ECM organization under the physiological and pathophysiological conditions. We investigated possible association of genetic promoter polymorphisms of MMP2 (rs243866), MMP8 (rs11225395), MMP9 (rs3918242) and TIMP2 (rs8179090) to varicose veins development in the Slovak population. Genomic DNA from 276 Slovak individuals (138 cases, 138 controls) was genotyped for selected SNPs (rs243866, rs11225395, rs3918242 and rs8179090) using the PCR-RFLP analysis. The data were analysed by chi-squared (chi2) test, logistic regression, and Mann-Whitney test. The risk of varicose veins development was evaluated in dominant, codominant and recessive genetic models. The statistical evaluation of selected polymorphisms in patients in all three genetic models has not shown a significant risk of varicose veins development. Our study has not shown the association between selected polymorphisms and increased risk of varicose veins development in Slovak population. More evidence with broaden sample size is needed.

Heart rate variability in adolescent major depression

Introduction

Impaired cardiac autonomic regulation is likely important contributor to a potential cardiac complications in major depression. The knowledge regarding the depression effect on cardiac regulation in adolescent age is limited. Aim was to study short-term heart rate variability (HRV) as an index of cardiac autonomic control in never-treated major depressive disorder (MDD) adolescent patients using linear and nonlinear methods related to depressive symptoms severity.

Methods

We have examined 20 MDD girls and 20 healthy age-matched girls at the age from 15 to 18 years. The ECG was recorded in three positions: supine - orthostasis - supine. The HRV was analyzed using linear (time and frequency analysis) and novel nonlinear (symbolic dynamics, time assymetry) methods. The severity of depressive symptoms was evaluated using the scales Montgomery-Asberg Depression Rating Scale (MADRS) and Children’s Depression Inventory (CDI).

Results

Several HRV linear and nonlinear parameters were significantly reduced in MDD group compared to controls in supine rest and during orthostasis. The HRV nonlinear analysis indices significantly correlated with depressive symptoms severity.

Conclusions

Linear and nonlinear analyses revealed reduced magnitude and complexity of the HRV indicating impaired neurocardiac regulation in adolescent major depression. In addition, new approach of HRV analysis using nonlinear methods provided important information about depressive symptoms severity and cardiac autonomic regulation relations.

Impact of early aggressive nutrition on retinal development in premature infants

The normal retinal development is interrupted by preterm birth and a retinopathy of prematurity (ROP) may develop as its consequence. ROP is characterized by aberrant vessel formation in the retina as a response to multiple risk factors influencing the process of retinal angiogenesis. Insulin-like growth factor I (IGF-1) and vascular endothelial growth factor (VEGF) play an important role in the process of normal retinal vascularization. Insufficient nutrition during the first 4 postnatal weeks results in low serum levels of IGF-1, which is essential for correct retinal vessels formation, ensuring survival of the newly formed endothelial cells. Low IGF-1 level results in stop of angiogenesis in the retina, leaving it avascular and prompting the onset of ROP. Keeping the newborns in a positive energetic balance by providing enough nutrients and energy has a beneficial impact on their growth, neurodevelopment and decreased incidence of ROP. The best way to achieve this is the early parenteral nutrition with the high content of nutrients combined with early enteral feeding by the own mother´s breast milk. Multiple studies confirmed the safety and efficacy of early aggressive nutrition but information about its long-term effects on the metabolism, growth and development is still needed.

Associations of CYP1A2 Polymorphisms with the Risk Haplotypes in Lung Cancer in the Slovak Population

Phase I enzymes, including cytochrome P450, family 1, subfamily A, and polypeptide 2 (CYP1A2), are involved in the activation of carcinogens to reactive intermediates that are capable of binding covalently to DNA to form DNA adducts, potentially initiating the carcinogenic process. The aim of present study was to investigate the association of CYP1A2 gene polymorphisms and haplotypes with lung cancer risk. A case-control study was carried out on 105 lung cancer patients and 189 controls. To investigate three CYP1A2 polymorphisms: rs2472299, rs2470890, rs11072508 we used a high resolution melting analysis. We found significant allele associations (rs2470890 and rs2422299) with lung cancer risk. We searched for meaningful associations for all variants in the dominant, recessive, and additive genetic models. Genotype associations in the recessive model were of marginal significance for the same single nucleotide polymorphisms. A haplotype analysis included five variants with the frequency higher than 1 %. The haplotype "acc", present with the highest frequency, was associated with increased lung cancer risk (38.7 % vs. 31.5 %; OR 1.38; 95 %CI 0.95-2.01). On the contrary, rare haplotype "gtc" was significantly associated with decreased lung cancer risk in the Slovak population. In conclusion, the present study identified the risk alleles and haploid genotype associations of the CYP1A2 gene in lung cancer.

Changes in Heart Rate Variability and Complexity in Young Patients with Type 1 Diabetes Mellitus after A 17 Month Follow-Up

The objective of this study was to investigate short-term changes in cardiovascular autonomic dysregulation in young patients with Type 1 diabetes mellitus (DM).

Repeated analysis of spontaneous heart rate oscillations (heart rate variability - HRV) was conducted at baseline and after a follow-up period of 17 month. R-R intervals were recorded over 1h in the supine position and heart rate signal was quantified using standard time and frequency domain and short-term complexity measures.

During the follow-up measurement the low frequency oscillations of heart rate were significantly elevated (p = 0.03) and sample entropy values reduced (p = 0.03) compared with the baseline measurement. HRV measures were significantly negatively correlated with the duration of DM.

In conclusion, the data indicate that cardiovascular autonomic neuropathy progresses in relatively short time frames and depends on the duration of DM. Its progression is associated with glycemic control. Complexity and variability analyses of heart rate provide a sensitive tool for the detection and follow-up of cardiovascular autonomic dysregulation in patients with Type 1 diabetes mellitus.

Diagnostic significance of a mild decrease of baroreflex sensitivity with respect to heart rate in type 1 diabetes mellitus

Decreased baroreflex sensitivity is an early sign of autonomic dysfunction in patients with type-1 diabetes mellitus. We evaluated the repeatability of a mild baroreflex sensitivity decrease in diabetics with respect to their heart rate. Finger blood pressure was continuously recorded in 14 young diabetics without clinical signs of autonomic dysfunction and in 14 age-matched controls for 42 min. The recordings were divided into 3-min segments, and the mean inter-beat interval (IBI), baroreflex sensitivity in ms/mm Hg (BRS) and mHz/mm Hg (BRSf) were determined in each segment. These values fluctuated in each subject within 42 min and therefore coefficients of repeatability were calculated for all subjects. Diabetics compared with controls had a decreased mean BRS (p=0.05), a tendency to a shortened IBI (p=0.08), and a decreased BRSf (p=0.17). IBI correlated with BRS in diabetics (p=0.03); this correlation was at p=0.12 in the controls. BRSf was IBI independent (controls: p=0.81, diabetics: p=0.29). We conclude that BRS is partially dependent on mean IBI. Thus, BRS reflects not only an impairment of the quick baroreflex responses of IBI to blood pressure changes, but also a change of the tonic sympathetic and parasympathetic heart rate control. This is of significance during mild changes of BRS. Therefore, an examination of the BRSf index is highly recommended, because this examination improves the diagnostic value of the measurement, particularly in cases of early signs of autonomic dysfunction.

Effects of acute normovolemic haemodilution on cardiorespiratory changes in hyperthermia and its physical treatment

As only one experimental study examining the effects of haemodilution on circulatory responses to hyperthermia has so far been published and there is no information on respiratory responses to hyperthermia during haemodilution or anaemia, this paper studied the effects of acute normovolemic haemodilution on cardiorespiratory changes during 42 degrees C hyperthermia and its recovery by body surface cooling in 16 anaesthetized adult rabbits. The animals were divided into two groups: haemodiluted group (Hct = 18.6 +/- 0.4%) and control group (Hct = 41.1 +/- 0.9%). In the haemodiluted group, acute normovolemic haemodilution was induced by 60% replacement of total blood volume with dextran. Haemodilution produced significant increases in minute volume (V(E), p < 0.02), heart rate (HR, p < 0.02) and central venous pressure (CVP, p < 0.02), but there was no significant change in mean arterial pressure (MAP). Hyperthermia caused significant increases in V(E) and HR in both the groups; however, V(E) and HR values were significantly higher in the haemodiluted group compared to the controls. CVP decreased (p < 0.05) during 42 degrees C hyperthermia only in the controls in the panting phase. MAP did not significantly change during over-heating in controls, but it significantly (p < 0.02) rose in the haemodiluted group. In the recovery phase, cooling led to significant decreases in HR and MAP in both the groups and to further increases in V(E) (p < 0.05) in controls, whereas V(E) decreased in the haemodiluted animals. There were found no significant cardiorespiratory differences between the two groups during cooling. Hyperthermia was accompanied by the higher values of minute volume and heart rate in the haemodiluted animals, indicating a greater activation of the respiratory and cardiovascular systems, which could result in diminished functional cardiorespiratory reserve and a higher risk of respiratory and circulatory failures in haemodiluted/anaemic animals during hyperthermia. In the phase of recovery of the body temperature there were no significant cardiorespiratory differences found between the two groups.

Cardio-respiratory interaction and autonomic dysfunction in obesity

We aimed to test whether the evaluation of the cardio-respiratory interaction using the analysis of heart rate and blood pressure variabilities and respiratory maneuvers can reveal cardiovagal dysfunction in obese adolescents 12-18 years old. The spectral power in high frequency band of the heart rate variability (HRV) reflecting respiratory sinus arrhythmia was used as an index of the cardiac vagal control, and the spectral power in high frequency band of the blood pressure variability (BPV) as an indicator of mechanical effects of respiration. The deep breathing test and Valsalva maneuver were applied. The obese group had a reduction in spectral power in high frequency band of the HRV. Differences in high frequency band spectral power of the BPV between the obese and control groups were not found. The finding of lower respiratory sinus arrhythmia, indicating a cardiovagal dysfunction in obese adolescents, can provide important diagnostic information about early subclinical autonomic dysfunction in obesity.

Effects of hypovolemia on hypercapnic ventilatory response in experimental hyperthermia

The present study was undertaken to evaluate the effects of hypercapnia on the cardiorespiratory control in normovolemic and hypovolemic rabbits during exogenous hyperthermia. Hypovolemia was induced by administration of furosemide, the body temperature (Tb) was gradually elevated to 42 degrees C by body surface heating. Subsequently, Tb was lowered back to the initial values by gradual cooling. Recordings were done at normothermia (TN=38 degrees C), during heating at 40 degrees C (TH1) and 42 degrees C (TH2), and in the course of Tb reverting toward the baseline values back at 40 degrees C (TC1), and finally after full return to the initial temperature value (TC2). The hypercapnic ventilatory response (HCVR) was estimated as the slope of minute volume (VE) on end-tidal CO2 (ETCO2) curves. We found that heating caused an increase in the VE slope in the normovolemic (NV), but not in hypovolemic (HV), rabbits. Between-group comparison revealed a significant increase in HCVR at TH2 and TC1 in NV vs. HV rabbits. Hypercapnia in hyperthermia (at TC2) was accompanied by a significant decrease in heart rate only in the hypovolemic group. Recovery of Tb was unaccompanied by appreciable changes in HCVR in either NV or HV groups. In the course of cooling, a decrease in heart rate during hypercapnic challenge was present in both group, in HV the drop was less prominent. We conclude that hypercapnia during heat stress in both normovolemic and hypovolemic rabbits is associated with altered cardiorespiratory responses. HCVR during exogenous hyperthermia is augmented in normovolemic, but not in hypovolemic, rabbits.

Cystic dysplasia of the rete testis. Case report

Cystic dysplasia of the rete testis (CDRT) is a very rare cause of a paediatric scrotal mass often associated with renal and other genitourinary tract anomalies. These complex malformations are probably due to a developmental defect of the mesometanephric system during embryogenesis. A case of asymptomatic scrotal swelling in a 4-year-old boy is presented. Ultrasonography, showed a cystic lesion of the left testis associated with absence of the left kidney. Orchiectomy was performed because of extensive gonad involvement. Pathologic examination revealed multiple, anastomosing, irregular cystic spaces of varying sizes and shapes predominantly located in the region of the rete testis. The cysts had spread irregularly, displacing the testicular parenchyma, which was subsequently compressed under the tunica albuginea. Preoperative diagnosis of CDRT is easy if age, precise localisation, characteristic ultrasonographic features and other genitourinary malformations are considered. Other paediatric cystic lesions should be included in the differential diagnosis. It is possible to cure CDRT by orchiectomy or by conservative treatment. Nowadays the later option is preferred, but diagnosis of CDRT must be precisely established and followed by careful monitoring.

Surfactant lung lavage using asymmetric high-frequency jet ventilation followed by conventional ventilation in rabbits with meconium aspiration

BACKGROUND

Severe impairment of lung functions in meconium aspiration syndrome (MAS) often needs the application of combined therapeutic approach. In our recent study, surfactant lung lavage during asymmetric high-frequency jet ventilation (HFJV) removed more meconium than surfactant lavage during conventional ventilation, however, after the lavage excessive CO2 elimination was observed during HFJV.

OBJECTIVES

We hypothesized that the combination of asymmetric HFJV during surfactant lung lavage and conventional ventilation in the post-lavage period may be of benefit in a rabbit model of MAS.

METHODS

Suspension of human meconium in saline (25 mg/ml, 4 ml/kg) was instilled into the tracheal tube of conventionally ventilated (frequency, f, 30/min, inspiration time, Ti, 50%) anesthetized rabbits to cause a respiratory failure. Animals were then lavaged (10 ml/kg in 3 portions) with diluted surfactant (Curosurf, 100 mg of phospholipids/ml) or saline during asymmetric HFJV (f, 300/min, Ti, 70%). After the lavage, animals were ventilated conventionally (f, 30/min, Ti, 50%) for next 1 hour.

RESULTS

Surfactant lung lavage during asymmetric HFJV removed more meconium pigments and solids than saline with HFJV (p < 0.05 or p < 0.01, respectively). Moreover, application of asymmetric HFJV facilitated the lavage fluid removal in both groups. In the post-lavage period, improved oxygenation, lung compliance, right-to-left pulmonary shunts, and reduced ventilatory requirements were found in the surfactant group (p < 0.05), while pCO2 was kept in the normal range.

CONCLUSIONS

Surfactant lung lavage by asymmetric HFJV followed by conventional ventilation is advantageous combination in rabbits with MAS and may be tested in neonatal MAS (Tab. 2, Fig. 2, Ref. 12).

Lung lavage using high-frequency jet ventilation in rabbits with meconium aspiration

AIM

To determine the efficacy of the expulsion effect of high-frequency jet ventilation (HFJV) on meconium clearance from the airways in comparison with conventional suctioning in adult rabbits with meconium aspiration.

METHODS

Experiments were carried out on tracheotomized, anaesthetized and paralysed adult rabbits. A suspension of human meconium in saline (25 mg ml(-1), 4 ml kg(-1)) was instilled into the tracheal cannula. When respiratory failure developed, saline lavage (10 ml kg(-1) in 3 portions) was performed during conventional ventilation or by means of the inpulsion and expulsion regime of HFJV. Animals were further ventilated for 2 h with either conventional ventilation or HFJV.

RESULTS

There was no significant difference between groups in the amount of meconium recovered by lavage. Compared to conventional ventilation, the application of HFJV enhanced the elimination of carbon dioxide, increased lung compliance and diminished right-to-left shunts after 30 min of ventilatory treatment. Oxygenation also improved during HFJV, although this was not a consistent finding during the ventilation period.

CONCLUSION

HFJV improved gas exchange, lung compliance and reduced right-to-left pulmonary shunts, but saline lung lavage by HFJV was not found to be more efficient than lavage during conventional ventilation in rabbits with meconium aspiration.

Do the oscillations of cardiovascular parameters persist during voluntary apnea in humans?

The aim of this study was to ascertain the persistence of heart rate and blood pressure oscillations at the onset of voluntary apnea in humans and to assess the dependence of the fluctuations parameters on the chemoreceptor activity. In 24 young subjects (10 males, 14 females, mean age 20.4 years) heart rate (represented by its reciprocal value--RR-intervals), systolic blood pressure (SBP) and diastolic blood pressure (DBP) during controlled breathing (CB) of atmospheric air and oxygen followed by apnea were recorded continuously. The cosine functions were then fitted by nonlinear regression analysis to the heart rate, SBP and DBP oscillations during CB and at the onset of apnea. The parameters of oscillations were different during atmospheric air breathing compared to oxygen breathing. During oxygen breathing there was an increase of the RR-interval oscillations--relative bradycardia and enhanced magnitude of respiratory sinus arythmia. During apnea, the base level of the blood pressure oscillations was higher after breathing of atmospheric air compared to oxygen breathing. At least one cosine-like wave oscillation was present at the onset of apnea in the heart rate, SBP and DBP and the second wave was present in all assessed parameters in at least 70% of recordings. The oscillations in RR-intervals are, to some extent, independent of blood pressure oscillations. No significant gender differences were found either in the duration of breath holding or in the RR and SBP oscillations parameters.

Heart rate recovery after exercise: relations to heart rate variability and complexity

Physical exercise is associated with parasympathetic withdrawal and increased sympathetic activity resulting in heart rate increase. The rate of post-exercise cardiodeceleration is used as an index of cardiac vagal reactivation. Analysis of heart rate variability (HRV) and complexity can provide useful information about autonomic control of the cardiovascular system. The aim of the present study was to ascertain the association between heart rate decrease after exercise and HRV parameters. Heart rate was monitored in 17 healthy male subjects (mean age: 20 years) during the pre-exercise phase (25 min supine, 5 min standing), during exercise (8 min of the step test with an ascending frequency corresponding to 70% of individual maximal power output) and during the recovery phase (30 min supine). HRV analysis in the time and frequency domains and evaluation of a newly developed complexity measure - sample entropy - were performed on selected segments of heart rate time series. During recovery, heart rate decreased gradually but did not attain pre-exercise values within 30 min after exercise. On the other hand, HRV gradually increased, but did not regain rest values during the study period. Heart rate complexity was slightly reduced after exercise and attained rest values after 30-min recovery. The rate of cardiodeceleration did not correlate with pre-exercise HRV parameters, but positively correlated with HRV measures and sample entropy obtained from the early phases of recovery. In conclusion, the cardiodeceleration rate is independent of HRV measures during the rest period but it is related to early post-exercise recovery HRV measures, confirming a parasympathetic contribution to this phase.

'Respiratory' oscillations of cardiovascular parameters during voluntary apnea

The aim of this study was to ascertain the persistence of heart rate and blood pressure oscillations at the onset of voluntary apnea in humans. In 24 young subjects (10 males, 14 females, mean age 20.4 years) RR intervals, systolic blood pressure (SBP) and diastolic blood pressure (DBP) during controlled breathing (CB) of atmospheric air followed by voluntary apnea on FRC level were recorded continuously. The cosine functions were then fitted by nonlinear regression analysis to heart rate, SBP and DBP oscillations during CB and at the onset of apnea. During apnea, the changes of base of RR intervals indicate primary tachycardic reaction followed by a decrease in heart rate. The base of the blood pressure oscillations was higher (hypertensive reaction) in apnea. At least one cosine-like wave oscillation was present at the onset of apnea in heart rate, SBP and DBP and the second wave was present in all assessed parameters at least in 70% of recordings. There were no significant gender differences neither in the duration of breath holding nor in the RR and SBP oscillations parameters.

[The autonomic nervous system and hypertension]

It was shown that dysregulation of the cardiovascular system plays an important role in the development of arterial hypertension. Sympathetic drive can be increased mainly in cases of borderline and essential hypertension. The rise in sympathetic activity is not well balanced by the adequate increase in parasympathetic activity, even the PS tone is diminished. Relative sympathotony can occur beside the absolute sympathotony due to the decrease in the PS tone with normal or quantitatively less diminished sympathetic drive. The cause of the ANS activity dysbalance remains unknown. Probably there exist disorders of generator and modulator activities in higher levels of CNS, baroreceptor regulation and other peripheral (humoral and other) mechanisms. Adequate and appropriate recording of different cardiovascular parameters mainly during activation of ANS by maneuvers (orthostasis, Valsalva, etc.) is necessary. Beat-to-beat registrations of blood pressure (e.g. by Penáz method FINAPRES), heart rate (RR intervals) are necessary for the evaluation of short term blood pressure and heart rate fluctuations. Important information about S/PS activities and the balance in heart rate regulation can be achieved by spectral and non-linear analysis of the HR variability. Regular physical aerobic exercise increases the parasympathetic tone and is beneficial for restoration of the disordered S/PS balance in young hypertonics. It can be used as non-pharmacological treatment of arterial hypertension.

[Diagnosis and treatment of functional disorders of the lower urinary tract in younger men]

BACKGROUND

Functional disorders of the lower urinary tract can manifest by different symptoms. This could be caused by inaccurate diagnosis and non-causal treatment in young men. Urodynamics is helpful in the differential diagnosis and treatment of such cases.

OBJECTIVES

Examination of lower urinary tract functions in young men and causal treatment of both bladder neck obstruction or impaired bladder.

METHODS

In a prospective study, a group of 38 young men were treated at mean age of 42 years (range 19-50 yrs). Chronic abacterial prostatitis was treated in all cases unsuccessfully. Patients with positive urinary infection, previous surgery of the lower urinary tract and neurogenic bladder were excluded. Urodynamics confirmed a bladder neck obstruction or impaired bladder, the symptom score revealed subjective difficulties (maximum 35 points). Patients with the obstruction underwent transurethral incision of the bladder neck. Patients with impaired bladder were administrated with distigmine bromid (Ubretid) 5 mg for 1 year, every other day. All patients were re-examined one year following the treatment.

RESULTS

Bladder neck obstruction occurred in 18 cases, and impaired bladder in 20 cases. Significant differences were found in relation to age (47 vs. 31 years, p < 0.01) and detrusor pressure at maximum flow (62 vs. 30 cmH2O, p < 0.01). There were no differences in peak flow rate (9 vs. 10 ml/s, p = 0.75), symptom score (19 vs. 18, p = 0.46), residual urine (45 vs. 100, p = 0.08) and maximum cystometric capacity (341 vs. 383 ml, p = 0.10). Transurethral bladder neck incision or distigmine administration improved the symptom score by 68.4% vs. 33.3%, peak flow rate 50.0% vs. 23.1% and residual urine 100% vs. 75%.

CONCLUSIONS

Treatment of lower urinary tract disorders is successful in causal treatment of bladder neck obstruction and impaired bladder. (Tab. 2, Fig. 2, Ref. 12.)

[Diagnosis of intrinsic urethral sphincter insufficiency in women]

OBJECTIVE

Evaluation of intrinsic sphincter deficiency (ISD) according to the urethral leak point pressure in female population with stress urinary incontinence.

DESIGN

Prospective clinical study.

SETTING

Department of Urology, Jessenius School of Medicine Comenius University Martin, Slovak Republic.

METHODS

Study population compromise of 204 females with lower urinary tract symptoms. Exclusion criteria were neurogenic bladder and unstable bladder. Valsalva leak point pressures were evaluated (VLPP). ISD was defined if VLPP below 65 cm H2O has been occurred. Pad weighing test (PWT) was positive after leakage of 2 g per hour and more.

RESULTS

Stress urinary incontinence was in 134 and continence in 70 cases (control group). The first stage of incontinence was in 83, the second stage in 45 and the third stage in 6 cases of incontinence group. ISD has been occurred in 14 cases (10.5%), 8 cases with the second stage and 6 cases with the third stage. The best correlation was between VLPP and PWT, symptoms of incontinence and age of patients. All ISD cases underwent antiincontinent surgery with urethral suspension, some years ago.

CONCLUSION

ISD has been risen in the second stage (6%) and the third stage (4.5%), also, in the female population with stress urinary incontinence.

[Evaluation of heart rate variability and its usefulness]

The article presents a review of the method of the evaluation of the heart rate variability using spectral analysis and of the cardiovascular regulation evaluation using cardiovascular tests. It refers about the application in physiological research. The importance of the heart rate variability examination will increase in the future according to the sensitivity, noninvasivity and precision.

Heart rate variability and cardiovascular tests in young patients with diabetes mellitus type 1

The aim of this study was to obtain information about parameters of heart rate variability (HRV) in three frequency bands (high frequency - HF, low frequency - LF and very low frequency - VLF), the sensitivity of cardiovascular tests, and subjective feelings depending on autonomic nervous system balance in a group of young patients with diabetes mellitus type 1 (IDDM). Sixty-four subjects were examined: 32 patients with diabetes with a mean age of 16.1 +/- 0.7 years and a mean duration of IDDM of 6.3 +/- 0.8 years, and 32 healthy controls matched for age, sex and BMI. Shorter R-R intervals and abnormal values reflecting HRV were found in the diabetic group. In particular, parameters of total power, and HF and LF bands were reduced. The ratio VLF/HF power revealed predominance of sympathetic tone in the diabetic subjects. Although relative power VLF was increased in the supine position, the reactive rise of the VLF band activity in orthostasis was lower in the IDDM group. Using cardiovascular tests (deep breathing, Valsalva, orthostasis), significant differences in reactions were found only in the deep breathing test. Evaluation of sympathetic:parasympathetic:indifferent subjective feelings by questionnaire did not reveal any differences between the diabetic and healthy groups.

Changes in parameters of mechanics of breathing during high-frequency jet ventilation: what is the cause?

In experiments on 51 healthy anaesthetized and paralyzed rabbits the changes in parameters of mechanics of breathing during high frequency jet ventilation (HFJV) were determined and the mechanisms responsible for these changes were investigated. In the first series of experiments with two groups of animals ventilated by HFJV with relative inspiratory time ti=0.5 and ti=0.7 airway resistance (Raw) after 5 h of HFJV in the ti=0.5 group increased from 1.14+/-0.05 to 2.31+/-0.09 kPal(-1) x s (P < or = 0.001), in the ti=0.7 group from 1.22+/-0.04 to 1.78+/-0.08 kPal(-1) x s (P < or = 0.01). Dynamic compliance (Cdyn) decreased in the ti=0.5 group from 0.041+/-0.004 to 0.017+/-0.001 l x kPa(-1) (P < or = 0.01) and in the ti=0.7 group from 0.034+/-0.003 to 0.022+/-0.002 l x kPa(-1) (P < or = 0.01). In the second series of experiments a group of animals was ventilated by HFJV after cervical vagotomy. The deterioration of Raw and Cdyn was significantly reduced in vagotomized rabbits in comparison to the controls without vagotomy. Finally, the study of phospholipid content in bronchoalveolar lavage fluid revealed no significant differences after 5 h of artificial ventilation or spontaneous breathing. These data indicate that HFJV results in changes in the parameters of mechanics of breathing in healthy lungs, which may be attenuated, but not fully eliminated, by bilateral cervical vagotomy. The decrease in Cdyn and increase in Raw are probably not due to changes in the pulmonary surfactant content.

[Pulmonary surfactant]

Study of the pulmonary surfactant system has brought important information about its composition, metabolism and functions in the last decades. Besides phospholipids an important role is played by surfactant proteins (SP-A, B, C, D). These proteins aid not only the reduction of the surface tension of the alveoli, but they are involved in regulation of surfactant synthesis, secretion and in local immune defense in the lungs. Impairment of surfactant was found not only in premature newborns (IRDS), but also in cases of meconium aspiration, pneumonia and in other lung diseases in adults. Therapy by stimulation of surfactant synthesis and secretion and by intrapulmonary application of exogenous surfactant was proved effective in therapy of surfactant-deficiencies.

[Cardiovascular and hemodynamic changes after artificial pulmonary ventilation]

The cardio-respiratory interactions include mechanical, reflex and humoral mechanisms. However, in the organism they mutually overlap, thus mating their separate investigation is problematic. Mechanical effects of conventional artificial ventilation (AV) and high frequency ventilation (HFV) are elicited by increased intrapulmonary pressure during lung inflation, as well as during application of positive end expiratory pressure (PEEP). The increase in intrapulmonary pressure compresses the pulmonary vessels and increases the pulmonary vascular resistance. These changes deteriorate the right ventricular function. Mechanical factors are responsible for the fall of the left ventricular (LV) filling, stroke volume and alteration of the LV preload and afterload. LV filling is decreased during artificial ventilation (AV) owing to the shifting of blood from the central to the peripheral circulation, and to the rise in pulmonary vascular resistance. Application of positive intrathoracic pressure during ventricular ejection phase can diminish LV afterload and increase the cardiac output. This effect is striking in LV failure. The reflex effects of artificial ventilation are due to the activation of baroreflexes and pulmo-vagally cardiac and vasoactive reflexes. Activation of these reflexes depends on the level and characteristic of the pressure in the airways, lungs, heart and vessels. Humoral effects of AV on the cardiovascular system and hemodynamics are triggered by lung expansion, circulatory changes, and they result in a release of vasoactive substances from lung parenchyma. (Fig. 5, Ref. 45.)

Contribution to occupational angiopathy diagnosis using special examination method

The authors presented 1642 cases of professional diseases caused by vibrations (VD) and 435 cases of extremity overload disease (EOD) diagnosed in the years 1974-1993. In addition to the standard rheoplethysmography there were evaluated the results of digital laser Doppler flowmetry (Moor instruments, UK) in 104 workers exposed to vibration (EV) and 25 controls with the age and smoking habit standardisation. In the selected subgroup were used continual measurements of digital blood pressure (Finapress, Ohmeda), digital LD flux and speed and the measuring of digital skin and central body temperature simultaneously. The records before and after 10 min of local cooling test (Rejsek method) and postocclusive hyperemic tests were summarized (computer evaluation, program STATGRAPHICS, T-test). Vasoconstriction to local cooling persisted in EV for longer time. The records of digital skin flux and speed, digital blood pressure reactions of EV were significantly different (EV/controls) also in the 10th min after cooling. Postocclusion hyperemic tests revealed good functional capacity also in EV. Advantages and disadvantages of methods were discussed. The results found by non-invasive methods in VD were in good relation to images obtained by means of radionuclides (clearance and cumulative tests). Cumulative tests (after 99m--pertechnetate i.v.) can be used in the selected differential diagnostic cases of angiopathies to help to distinguish degree of angiospastic and angioparalytic changes in the hands of VD, and also in special cases at angiopathies connected with EOD.

Cardiorespiratory parameters and respiratory reflexes in rabbits during hyperthermia

The effects of different body temperature (BT) on the respiratory and cardiovascular parameters and respiratory reflexes were studied in 33 anaesthetized adult rabbits. Hyperthermia elicited panting with mean panting respiratory rate 199 +/- 14 x min-1 in all anaesthetized rabbits. Significant correlations between BT and frequency of breathing (positive), heart rate (positive) or tidal volume (negative) were found. Cooling was accompanied by considerable arterial hypotension. Duration of the Hering-Breuer reflex (HB) was reduced by the rise of BT. Intensity of the reflex (assessed as the ratio of the apnoeic pause to the mean duration of the previous 5 breaths) was unchanged up to the body temperature eliciting panting (41.15 +/- 0.08 degrees C) when it was greatly diminished. Defensive airway reflexes were also changed in hyperthermia. The duration as well as the intensity of nasal apnoea (Kratschmer's reflex) and laryngeal chemoreflex apnoea were decreased. The intensities of respiratory efforts in sneezing and laryngeal coughing were reduced. The expulsive reactions evoked by mechanical stimulation of the larynx were replaced by very shortlasting inhibition of breathing during panting. The results indicate that reflex control of breathing via the Hering-Breuer reflex and the ability to eliminate irritants from the airways are diminished during hyperthermia and panting in anaesthetized rabbits.

Defensive reflexes of the respiratory system in anaesthetized rabbits during high frequency jet ventilation

The defensive airway reflexes during high frequency jet ventilation (HFJV) were studied in anaesthetized, non-vagotomized (n = 16) and vagotomized (n = 11) rabbits. The animals were ventilated by a high frequency jet ventilator. Sneezing and coughing were evoked by mechanical stimulation of the airways. During HFJV spontaneous breathing was inhibited only in the non-vagotomized rabbits. Mechanical stimulation of the airways during HFJV evoked sneezing and coughing, in which the inspiratory component was inhibited. This inhibition occurred not only in defensive reflexes evoked from the regions with increased pressure (trachea, bronchi), but also from the nose. Vagotomy diminished but did not fully eliminate the changes in sneezing accompanying HFJV. The intensity of maximum expiratory efforts was not significantly affected by HFJV in both subgroups.

[The pulmonary surfactant factor. Current knowledge, research trends and use in clinical practice]

Investigation of the composition and significance of individual components of the surfactant indicated that besides phospholipids an important role is played also by surfactant proteins. They aid not only the reduction of the surface tension of the lungs (SP-B, SP-C), but serve also in regulation of surfactant secretion (SP-A) and in local defense and immune responses in the lungs (SP-A and SP-D). Impairments of surfactant were discovered not only in RDS, but also in cases of meconium aspiration, congenital diaphragmatic hernia, pneumonia, pulmonary edema, idiopathic fibrosis of the lungs, alveolar proteinosis, pneumothorax, and bronchial asthma. Therapy by means of exogenous surfactant was proved effective in therapy of RDS. Occasional cases of exogenous surfactant therapy in other pulmonary diseases are auspicious, it is necessary, though, to develop and produce a sufficient amount of exogenous surfactant of high quality and at an acceptable price and to find an optimal manner of surfactant administration into the lungs. A significant perspective is anticipated to utilization of intrapulmonary administration of the exogenous surfactant as a carrier of further active substances for local administration into the lungs. (Ref. 36.)

[Mechanisms of thermoregulation in fetuses and children]

In the submitted review the authors discuss the problem of thermoregulation in foetuses and children. Attention is devoted in particular to the action of thermoregulating nervous and hormonal mechanisms.

[Use of high-frequency modulated continuous positive airway pressure in experimental respiratory distress syndrome and pulmonary edema]

The effect of high frequency (f = 300.min-1) modulated continuous positive airway pressure (CPAP) (0.49 kPa) was compared with that of CPAP without modulation (0.49 kPa) in 24 anesthetized rabbits in experimental respiratory distress syndrome (RDS) and pulmonary edema. RDS was induced by single excessive lavage of the lung on using the impulse and expulse effect of high frequency jet ventilation. Pulmonary edema was elicited by i.v. administration of a mixture of fatty acids. Decreased dynamic compliance of the lung and increased respiration work and rate were recorded both in experimental RDS and pulmonary edema. In RDS paO2 was reduced and paCO2 increased. In pulmonary edema, despite diminished respiration volume, ventilation was enhanced by the higher respiration rate and both paO2 and paCO2 were reduced. Application of CPAP resulted in normalization of blood gases. Modulated CPAP, compared to CPAP without modulation, further decreased paCO2 and increased paO2. The results obtained in experimental models of RDS and pulmonary edema in rabbits show the beneficial effect of high frequency modulated CPAP by pressure oscillation on values of blood gas tension.

[Does short-term high-frequency jet ventilation damage the tracheobronchial mucosa?]

In anesthetized rabbits, the occurrence of histopathological changes was studied above below and the level of the endotracheal tube opening after one-hour high-frequency jet ventilation (f = 150.min-1,Pin = 70-90 kPa, Ti = 0.5) with nonhumidified air and oxygen mixture (FiO2 = 0.6). The findings were compared with those obtained in intact rabbits and in rabbits which were inhaling nonhumidified air from the environment spontaneously via the endotracheal tube. Mechanical obstruction of the airways by mucus or necrosis of the mucous membrane was not observed. The major histopathological changes characteristic of inflammation and mechanical damage of the mucosa were recorded above the opening of the endotracheal tube. Towards the main bronchi the degree of the injury was decreasing. (Tab. 2, Fig. 2, Ref. 11.)

[The effect of postural changes on respiration and blood pressure in premature neonates]

Changes in respiratory rate, heart rate, and blood pressure in supine, orthostatic (45 degrees), and prone position were studied in 23 premature neonates of mean gestational age 34.5 weeks (30-36), mean birth weight 2100 g (1540-2480) and mean postnatal age 52 hours (12-72). The individual positions of the newborn were changed in 5-minute intervals. In the orthostatic position, the respiratory rate decreased, yet heart rate and blood pressure did not change. In pronation, respiration became more regular. In the preceding supine position, the coefficient of variation of the duration of respiratory cycles was 28.2 +/- 3.5%, while in the 1st minute of pronation it was 15.9 +/- 2.4% and in the 5th minute 14.3 +/- 1.9% (p < 0.001). In the 5th minute of pronation systemic blood pressure was increased. (Tab. 1, Fig. 4, Ref. 20).

[Changes in the parameters of respiratory mechanics after the aspiration reflex and asphyxia]

Parameters of respiration mechanics (dynamic compliance--Cdyn and total lung resistance--RL), ventilation, blood gases, and right-to-left pulmonary shunts were studied after aspiration reflex in experiments on 29 anesthetized cats. Attacks of aspiration reflex were induced without asphyxia (8 cats) and during two-minute asphyxia (9 cats). The control group consisted of 12 animals. A series of aspiration reflex attacks resulted in short-term improvement of the parameters of respiration mechanics with an increase in Cdyn and reduction of RL. A simultaneous elevation of PaO2 and a decrease of PaCO2 were recorded. In combination with asphyxia (hypoxemia and hyperkapnia), the aspiration reflex induced a reversed reaction, i.e. decreased Cdyn lasting till the end of experiment (3 hours) and an increase of functional alveolar right-to-left shunts. The results indicate that in cats impairment of respiration mechanics parameters is brought on only when deep inspiration is combined with asphyxia.

[New methods of artificial respiratory ventilation]

High frequency ventilation, a new nonconventional method, has been introduced into clinical practice also in Czechoslovakia, where mainly high frequency jet ventilation (HFJV) is being developed. The HFJ ventilator Best-2 (Konstrukta, Trencín) and Chirajet (Chirana, Stará Turá) which enable HFJV with a multijet generator are used. These equipments reduce inadvertent positive end expiratory pressure by means of an expiration jet and are so designed that Brychta's impulse and expulse regimen can be used to advantage at programmed lavage of the lungs and at selective ventilation of individual parts of the lungs. The paper presents the basic principles of HFJV as well as the author's experience in using this method of ventilation in experimental animals.

[Reversible cardiorespiratory failure induced by CO2 inhalation in cats]

Experiments on anesthetized cats showed that short-term inhalation of concentrated CO2 induced reversible asphyxia resulting in acute cardiorespiratory failure. The stage of hyperventilation was followed by apnea initially interrupted by primary gasps and by bradycardia and drop in systemic blood pressure. After termination of CO2 supply in the state of apnea or after onset of resuscitation the blood pressure started to increase, secondary gasps appeared and regular respiration was gradually restored. The rate and duration of gasps decreased but the inspiratory force and the achieved tidal volume and airflow were greater than at normal respiration. During reversible asphyxia induced by CO2 inhalation the ECG exhibited invariably severe arrhythmias, most frequently atrioventricular block of different degrees. Bilateral cervical vagotomy failed to prevent the occurrence of ECG changes. After administration of Indral, however, arrhythmias were recorded only exceptionally.

[The effect of trigeminal zone irritation on parameters of forced vital capacity in humans]

In 44 healthy males aged 18-21 years, the authors studied the effect of irritation of the trigeminal zone by ammonia vapors and by immersion of the face into water on parameters of forced vital capacity. Inhalation of ammonia immediately induced impairment of all the studied parameters of forced expiration. In the later time intervals (up to the 10th minute after inhalation) the air flow remained reduced over the whole forced expiration (FVC/FET), mainly at the expense of decreased air flow at the end of forced expiration (FEF75-85%). Inhalation of ammonia also resulted in abolition of the psychically induced higher heart rate and in its normalization. Immersion of the face into cold water caused reduction in the values of FVC, FEV1, FVC/FET, and FEF0-25%. After voluntary apnea in the air there was only a small reduction of FEF0-25%. In the light of these findings, the authors consider irritation of cold receptors of the face to be the main cause of the changes in functional parameters of the lungs during immersion reflex.

Heart rate and its variability in juvenile hypertonics during respiratory maneuvers

In 27 children (14 juvenile hypertonics and 13 healthy control children, with the mean age 14.7 +/- 0.4 y. or 15.2 +/- 0.5 y., respectively, P greater than 0.05) the changes of heart rate (HR), its variability (HRV) during deep inspiration and subsequent expiration, Valsalva's maneuver, doubled breathing frequency and the deepening of breathing were studied. The resting supine mean HR was significantly higher (P less than 0.001) in hypertonics than in controls. Deep inspiration was in both groups accompanied with the HR increase. However, the percentage increase in hypertonics was significantly lower than in normals (P less than 0.02). With subsequent expiration, the HR fell in both groups. There was no significant difference between the percentage decreases in both groups (P greater than 0.05). During the Valsalva's maneuver, in the first phase the tachycardic response occurred, which was in hypertonics significantly less pronounced. After the recovery of breathing a bradycardic reaction occurred which was equal in both groups (P greater than 0.05). Both, in juvenile hypertonics and in controls the doubled frequency of breathing increased the mean HR and decreased the HRV. During the deepened breathing there was an increase in mean HR in both groups, and only in the controls there was an increase in HRV. Heart rate variability in hypertonics was lower than in the controls under all the conditions.

Upper airway reflexes in newborns with respiratory distress syndrome

In 16 newborns with respiratory distress syndrome (RDS) not artificially ventilated, oesophageal pressure was recorded with an electromanometer and the reactions to mechanical stimulation of the upper airways by means of a nylon fibre were investigated. The results were compared with the values obtained in 16 newborns without cardiorespiratory disturbances. The reactions were evoked by mechanical stimulation of the airways. Mechanical stimulation of the nasal mucosa produced expulsive reactions only in 45% of cases in newborns with RDS as compared with 95% in healthy newborns (p less than 0.001). Stimulation of the oropharyngeal and laryngeal regions elicited expulsive reactions in 48% of cases in newborns with RDS, but 74% in healthy newborns (p less than 0.001). In other cases, inhibition of breathing or apnoea was the most common reaction. The expulsive component of responses such as sneezing, expiratory reaction and crying was weaker in newborns with RDS than in control infants. The inspiratory component of sneezing and coughing, on the contrary, was stronger in newborns with RDS. These results indicate that active elimination of irritants from the airways is reduced in newborns with RDS.