Series dead space volume assessed as the mean value of a distribution function

Series dead space (VdS) is assumed to be represented by that volume exhaled until alveolar gas is observed. Phase II of the single breath CO2-diagram contains the (flow, concentration and sequence weighted) distribution off all stationary interfaces (SI) expired before phase III. We describe a new method to estimate the mean value of VdS based on the differentiation of phase II. This approximation of VdS is called the 'Pre Interface Expirate' (PIE) and is compared in this study with the integrative approach of Langley. Tidal volume (Vt) and PEEP were varied from 71 to 123% and from 0 to 6 cmH2O respectively. The estimation of VdS by differentiation of phase II (PIE) shows excellent reproducibility and depends only on phase II - not on phase III and IV as does VdS-Langley. PIE does not depend on Vt and PEEP per se but reflects the distension of convective airways due to elevated end-inspiratory airway pressure. Our results confirm the predictions of Paiva's model calculations in that the size of VdS is determined by the distension of airways rather than by the altered position of the SI.

Virilization without adrenal hyperplasia in 21-hydroxylase deficiency during fetal life

The characteristic excess production of androgens in the cortisol 21-hydroxylase defect is generally considered to be secondary to ACTH stimulation of alternate pathways. Whenever a morphological examination of the adrenals has been possible in this disorder, adrenocortical hyperplasia was a constant finding. The availability of methods for the prenatal diagnosis of the 21-hydroxylase defect has made it possible to examine some of the manifestations of this disorder during fetal life. We studied a severely virilized 20-week-old aborted female fetus with the 21-hydroxylase defect whose adrenals were neither grossly enlarged nor microscopically hyperplastic. In a pregnancy at risk for congenital adrenal hyperplasia due to a 21-hydroxylase deficiency, amniocentesis was performed in the 18th week of gestation. The 21-hydroxylase defect was established by HLA typing and highly elevated levels of 17-hydroxyprogesterone, testosterone, and androstendione in amniotic fluid. After counselling, the parents, who already had a girl with the salt-wasting form of 21-hydroxylase deficiency, wished termination of the pregnancy. The aborted 20-week-old fetus was within the normal range for gestational age in weight and height. The external genitalia were ambiguous and extremely virilized, with an enlarged clitoris and fused labioscrotal folds. A urogenital sinus opened at the base of the clitoris. The internal organs were female, with a normal uterus and ovaries. Both adrenals were normal in size and weight for their gestational age. Histological examination of the adrenals revealed no abnormalities, and no hyperplasia was detectable. Thus, the adrenals in the 21-hydroxylase defect during fetal life secrete excessive amounts of androgens and cause virilization in the absence of adrenocortical hyperplasia.

[Behavior of functional residual capacity in acute respiratory insufficiency]

Variations of functional residual capacity (FRC, estimated by the N2-washout technique) and oxygenation (PaO2/FIO2) were investigated in patients mechanically ventilated for acute respiratory failure (ARF, caused by pneumonia). The various ventilatory modes were compared. The results were as follows: 1. If FRC is reduced due to ARF, the reduction is diminished by PEEP. The quantitative amount of this effect cannot be predicted in the individual patients. 2. If CPPV is switched to IMV or CPAP with an equal PEEP value, FRC was not usually changed when the clinical course was favourable; however, FRC decreased if clinical signs of insufficient spontaneous respiration were present. The proportion of FRC reduction following such a change of respiratory mode was equal to the effect of removal of PEEP from 10 cm H2O to zero. 3. FRC and oxygenation do not undergo a parallel change in every situation. 4. Treatment and further research should focus not only on increasing reduced lung volume but mainly on diverting ventilation to perfused lung regions.

[The impossibility of direct flow measurements in lung function studies. Analysis of errors and compensation]

The authors demonstrate that the conditions for correct flow measurement are not fulfilled when a resistive flow transducer (Fleisch pneumotachograph, screen pneumotachograph etc.) is connected directly to the mouth or to the end of the endotracheal tube. This is because the composition, temperature and water content of the respiratory gas varies markedly within a respiratory cycle, the mechanically ventilated patient exhales with a huge expiratory initial peak flow, and laminar flow tends to switch over to turbulent flow in this system. Methods are proposed of continuously compensating the effects of changing gas composition, reducing expiratory peak flow without an increase in expiratory resistance, and preventing the occurrence of turbulent flow. The improvement of measuring accuracy to 2% makes the estimation of respiratory volumes more reliable. Secondly, the increased quality of primary data enables one to analyze these data in a more complex and sophisticated manner (N2-washout compartment analyses, VDS, investigation of complicated modes of ventilation such as IMV, etc.).

[Benign epithelial neoplasias of Vater's papilla]

Benign epithelial tumours of the papilla of Vater seem to be very rare. Since 1910, 75 cases have been published. 3 own cases were added. Diagnostic and therapeutic problems were discussed. Benign epithelial neoplasms of the papilla of Vater are precanceromatous. Many cases of carcinoma of the papilla may grow from benign adenomas. The treatment of choice is the local exzision of the adenoma, occasionally necessitating the reimplantation of bile and pancreatic ducts. The main problem is the treatment of adenomas with severe epithelial dysplasia. Metastatic deposits are possible but duodenopancreatectomy seems to be too aggressive an operation in such cases. In cases of severe epithelial dysplasia and focal invasion of the stroma duodenopancreatectomy should be performed. In cases of familial adenomatosis coli adenomas of the papilla should be thought of. In cases of adenomas of the papilla of Vater the colon should be examined to exclude a familial polyposis coli.

Composition of the major elements and trace elements of 10 methanogenic bacteria determined by inductively coupled plasma emission spectrometry

The elemental composition of 10 methanogenic species was determined by inductively coupled plasma emission spectrometry and by a C-H-N-analyzer. The 10 species were representative of all three orders of the methanogens and were cultivated under defined conditions. Special emphasis was given toMethanosarcina barkeri, represented by 5 strains and cultivated on various substrates. The following elements with the lowest and highest values in parentheses were determined: C (37-44%, w/w), H (5.5-6.5%), N (9.5-12,8%); Na (0.3-4.0%), K (0.13-5.0%), S (0.56-1.2%), P (0.5-2.8%), Ca (order I: 85-550 ppm; order II: 1000-4500 ppm), Mg (0.09-0.53%), Fe (0.07-0.28%), Ni (65-180 ppm), Co (10-120 ppm). Mo (10-70 ppm), Zn (50-630 ppm), Cu (<10-160 ppm), Mn (<5-25 ppm). The biggest variations were found with respect to N and K, which both seem to have important physiological functions. Although it is unknown whether zinc and copper are essential trace elements for methanogens, all investigated species contained remarkably high zinc contents, whereas copper seemed to be present only in some species.

A concept for breath by breath computing of lung compliance in the ventilated patient

A concept for calculating dynamic lung compliance (CL) by computer in ventilated supine patients is described. The primary signals are gas flow, airway pressure, esophageal pressure (PES) and ECG. Endinspiratory and endexpiratory PES is calculated as a mean value during an R/R interval's time just before the end of inspiration and expiration. Its main advantage is a reduction of the variability in computer calculated CL by reducing the influence of cardiac oscilliations on PES tracings, thus enabling evaluation of special ventilatory settings as intermittent mandatory ventilation or rapidly changing PEEP.

[Catheter epidural analgesia for treatment of postoperative and post-traumatic pain]

Postoperative epidural local anesthetics or opiates provide excellent analgesia but do not reduce the incidence of respiratory complications compared with systemic analgesics. Additional and sometimes lethal side effects reserve the routine use of epidural analgesia for highly selected patients. Thoracic epidural analgesia (TEA) may prevent ventilation in patients with serial rib fractures (SRF) without gross pulmonary parenchymal lesion. TEA results in fewer pulmonary complications, shorter hospital stay, and lower mortality than artificial respiration. Late global pulmonary tests after TEA for treatment of SRF show normal results within comparable groups without rib fractures.

Psychosocial and intellectual development in 12 patients with infantile nephropathic cystinosis

The psychosocial and intellectual development of 12 children with infantile nephropathic cystinosis was investigated longitudinally by use of biographical data, long-term behavioral observations and psychological assessment. Of the 12 patients, eleven suffered terminal renal failure and 7 of these were followed up after renal transplantation. In spite of the severe illness and the resulting unusual life conditions the patients showed normal intellectual capacity and most of them average school performance. The patients were socially adapted, their behavior was predominantly cooperative, shy and reserved, but depressive at times. After transplantation the children became more active and outgoing. However, growing discrepancies between their physical development and their emotional and social age may lead to adaptational problems at adolescence which may require psychological counselling.

[Monitoring of respiration: gas exchange and pulmonary hemodynamics]

The quantitative evaluation of pathological CO2 elimination and O2 uptake are discussed. CO2 elimination may be described by the concept of "functional dead space ventilation" (VD/VT) in a manner sufficient for clinical use. For this purpose it is necessary to measure PaCO2 and the concentration of CO2 in the mixed expired gas. For a quantitative definition of oxygen uptake it is necessary to relate PaO2 to inspiratory O2 concentration (F1O2), and this is best achieved using the "intrapulmonary right-to-left shunt". To calculate this ratio, mixed venous oxygen saturation as well as F1O2 and PaO2 have to be measured, which means that a pulmonary artery catheter has to be in place. A new interpretation of the N2 wash-out curve demonstrates that pathological changes of intrapulmonary gas diffusion may be responsible for difficulties in the interpretation of O2 uptake. Monitoring of pulmonary hemodynamics calls not only for a pulmonary artery thermodilution catheter but also monitoring of the course of body weight. However, recent work shows that the measurement of ventricular filling pressures must be related to the individual ventricular volumes in systole and diastole which are measurable today.

[Ocular myasthenia in sisters (author's transl)]

The case histories of two sisters with ocular infantile myasthenia are reported. The older girl has been suffering from the disease for 11 years now. Infantile myasthenia is clinically and genetically different from myasthenia gravis which occurs in older patients. The disease is probably due to a number of factors, a special genetical disposition which facilitates the specific effect of environmental factors. It cannot be ruled out, however, that in rare cases as for example in the family with parental consanguinity reported on here there is an autosomal recessive mode of transmission. The clinical and genetic heterogeneity of infantile myasthenia and the heredity of the disease are discussed.

Epidural analgesia or mechanical ventilation for multiple Rib fractures?

A protocol for treating thoracic trauma is proposed. Severe pulmonary lesion with increased venous admixture (e.g. contusio, atelectasis, aspiration) is treated by mechanical ventilation. Rib fractures with minor pulmonary lesion and therefore with only moderately abnormal gas exchange but with remarkably reduced vital capacity (even with flail chest) are controlled by thoracic epidural analgesia following vital capacity, tidal volume and respiratory rate. If both a severe pulmonary lesion and serial rib fractures are present, the patient is ventilated for 2-3 days and then extubated to breath spontaneously with epidural analgesia. The indication for a mechanical ventilation or for spontaneous breathing with thoracic epidural analgesia is therefore deducted more from functional variables than from morphological facts. The course of a consecutive series of 283 patients is presented. 155 patients were treated with primary ventilation and 112 patients with primary epidural analgesia, while 16 patients could be managed with general analgesia. The duration of treatment morbidity and mortality show this protocol to be very useful.

Nosocomial infections in intensive care wards: a multicenter prospective study

In a three-year prospective investigation, a total of 6,952 patients were investigated prospectively in nine intensive care wards and their rate of nosocomial infections was analysed. The frequency of the nosocomial infections varied between 3% and 27%. The most frequent nosocomial infections were urinary tract infections, sepsis, infections of the skin and of the subcutaneous tissue, pneumonia and wound infections. The most frequent causes of sepsis were ventilation pneumonia, venous catheters, wound infections and urinary tract infections. The pathogen spectrum was analysed. By specific control of infection with employment of an infection control nurse, the frequency of nosocomial infections on intensive care wards was lowered from 17.2% to 14.3% within one year in one of the hospitals.

Optimal endexpiratory airway pressure for ventilated patients

In patients ventilated for acute respiratory failure PEEP was changed either by gradual increase and decrease (5 cm H2O/min) or in steps of 5 cm H2O. The effects on gas exchange, pulmonary mechanics and pulmonary and systemic circulation were studied. Total compliance did not change uniformly and cardiac index decreased so much due to PEEP that the increase in PaO2 could not prevent the decrease of arterial oxygen transport. No variable was found helpful to predict the "best PEEP" in a clinical situation.

[Acute heart insufficiency of primarily non-cardiac origin after polytrauma]

The following approach is proposed for treatment of the hemodynamics resulting from severe trauma. Blood pressure and pulse frequency are measured whilst volume is added until peripheral circulation returns to normal or until CVP attains 13 mm Hg (under CPPV, PEEP 10 cm H2O). When CVP attains 13 mm Hg a pulmonary-arterial thermodilution catheter is introduced and transfusion continued, possibly up to a PCWP of 17 mm Hg. At this stage, 4 different haemodynamic groups may be distinguished and are described on the basis of the mean values recorded for 3 patients in each group: 1. SVRI increased, LVSWI and PVRI normal.

THERAPY

continued slow addition of volume. 2. SVRI and PVRI slightly elevated. LVSWI diminished. CI and VO2 adequate.

THERAPY

phentolamine. 3. PVRI slightly elevated, CI and VO2 too low, i.e. left cardiac insufficiency.

THERAPY

isuprel. 4. PVRI markedly elevated, CI and VO2 clearly diminished, i.e. biventricular cardiac insufficiency with pulmonary-vascular hypertension.

THERAPY

isuprel and phentolamine. Pharmacological therapy can be discontinued after a few days and hemodynamics remain normal. These observations show that "acute cardiac failure in fundamentally normal hearts" can occur after severe trauma and that treatment is possible.

Respiratory assistance on surgical wards with continuous positive airway pressure (Turbo-PEEP-Weaner)

Based on our own experience, we introduce a new continuous positive airway pressure device. The patient can breathe continuously positive airway pressure through a tight face mask, and thus the postoperative reduction in functional residual capacity is counteracted. This is shown by the well-documented clinical course of a 62 year old man who had respiratory insufficiency after proximal selective vagotomy.