Paediatric central venous catheter insertion.
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Catheterization, Central Venous↗
Biomedical subjects
R Stenz
Publications and source records attributed to R Stenz.
Latex allergy. A position paper of the British Society of Allergy and Clinical Immunology.
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Anesthesia↗
A new physiologically approached in vitro test for quick evaluation of the hemolytic activity of surfactants.
New physiologically approached in vitro assays are presented which allow rather quick and uncomplicated determinations of the hemolytic activity of surfactants, intended mainly to solubilize poorly soluble drugs in parenteral dosage forms. The extent and the rates of the hemoglobin release from erythrocytes during the incubation of blood with increasing additions of surfactants is thought to be a very suitable and realistic estimation of the membrane damaging side effects of amphiphilic substances. In this study the extent of free hemoglobin released into the plasma is determined by a spectrophotometric method, as well as by an enzymatic determination measuring the lactate dehydrogenase (LDH) activity. LDH is released in a similar way from damaged erythrocytes. The results of these two methods are compared. They correspond satisfactorily.
Adult↗
Pressure-time product and work of breathing during biphasic continuous positive airway pressure and assisted spontaneous breathing.
The pressure-time product (PTP) and work of breathing (W) were measured in 19 intubated patients during weaning from mechanical ventilation after aortocoronary bypass surgery. The patients were supported by two different ventilatory modes: biphasic continuous positive airway pressure (Biphasic CPAP; a ventilatory mode that permits spontaneous breathing at two different levels of airway pressure during inspiration and during expiration) and pressure-support ventilation (denominated as assisted spontaneous breathing, ASB). Our aim was to compare the energy cost of breathing imposed by both modes. The PTP was obtained by integrating the area enclosed by the esophageal and chest-wall static recoil pressure curves. The W performed by the patient (Wp) was calculated using Campbell's diagram method, based on the esophageal pressure curve and normalized per liter of ventilation. Two comparable support levels, corresponding to a high and a low degree of mechanical support, were studied for each ventilator mode. The levels of support were generally higher than that necessary to overcome inspiratory resistance. We found significantly higher PTP values during biphasic CPAP than during ASB (p < 0.01), whereas the Wp was the same with biphasic CPAP and ASB at both support levels. We conclude that because of the higher PTP values measured during biphasic CPAP, this mode of ventilation appears to have been more exhausting for our patients. The discrepancy between PTP and Wp is probably due to the different mechanisms of support given by the two ventilatory modes and the greater patient effort is related to those respiratory cycles that are not helped by the ventilator and which represent nearly half of the breaths during biphasic.
Aged↗
[Metabolic acidosis in the 32nd week of pregnancy--uncontrolled diabetes in pregnancy, dehydration or sequela of tocolysis?].
We describe a case of keto- and lactic acidosis in a 22 year old, healthy woman hospitalized for preterm labor at week 32 of gestation. One former pregnancy was normal. Blood glucose level at admission was 115 mg/dl after 8 mg of betamethasone. Continuous salbutamol infusion was used for management of preterm labour. 18 hours later, the patient complained about nausea and dyspnoea followed by tachypnoea and hyperventilation. Blood gas analysis showed severe metabolic acidosis (ph 7.25, BE-17.5, pO2 114 mm Hg, pCO2 15.5 mm Hg). At this moment blood glucose level was 178 mg/dl. Ketone bodies in urine were positive, serum lactate level was also elevated at 8.6 mmol/l. Cesarean section was performed because of prolonged fetal bradycardia. 6 months post partum type-I-diabetes could be excluded. We conclude that this case of acidosis was due to both, beta-2-adrenergic treatment and beginning gestational diabetes.
Acidosis, Lactic↗
[Surgical management of acute lateral ligament rupture of the upper ankle joint].
In a retrospective study carried out at the Department of Traumatology of the Hospital of Böblingen 169 patients with recent ruptures of the fibular ligament operated on from 1.1.1991 to 31.12.1992 were asked for a clinical examination with stress radiography. 110 patients underwent this follow-up examination, 7 sent back the questionnaire. 99% of the patients were content with the results of the operation. Most patients see the advantage of a short period in a cast and afterwards tape therapy.
Adolescent↗
[The elimination of carboxyhemoglobin--gender-specific and circadian effects].
We investigated sex-specific and circadian variations of carboxyhemoglobin (COHb) elimination in healthy volunteers. COHb elimination follows an exponential function with a baseline found in nonsmoking women at 1.72% and in nonsmoking men at 1.79% COHb saturation. During the day, the elimination half-life time (t1/2), determined by eleven hourly samples after stopping smoking was significantly (Wilcoxon-test, p less than .01) shorter in women (3.2 +/- .4 hours, mean +/- standard deviation, n = 7) than in men (4.5 +/- 0.4, n = 6). During the night, too, t1/2 calculated from 2-point measurements after the smoking halt was significantly (Wilcoxon-test, p less than .05) shorter in women (4.3 +/- 1.1, n = 4) than in men (8.0 +/- 1.6, n = 5). In men, t1/2 during the night was significantly longer (p less than .01, Wilcoxon-test) than during the day. The day/night difference may be caused by reduced alveolar ventilation during sleep. Less muscle mass and, therefore, less myoglobin as a depot for carbon monoxide may account for the shorter half-life time of carboxyhemoglobin in women. We conclude that these variations of COHb-elimination should be taken into account when a smoking halt is advised, for instance, preoperatively.
Carboxyhemoglobin↗
[Carboxyhemoglobin in smokers and a preoperative smoking cessation].
The proportion of carbon monoxide-haemoglobin (COHb) in blood was determined before elective surgery on 50 patients (12 women and 38 men; mean age 39.5 [21-68] years) who were smoking at least 20 cigarettes a day, at two moments: during ad lib smoking and after a smoking halt of more than nine hours. 50 nonsmokers (25 women and 25 men; mean age 29.5 [20-48] years) served as controls. COHb proportion before smoking halt averaged 6.9 +/- 1.8%, after halt it averaged 3.8 +/- 1.1% (P less than 0.001). Individual values over 6% were found even after abstinence. COHb proportion in nonsmokers was 1.8 +/- 0.2% (nonsmokers vs. smokers: P less than 0.001 with and P less than 0.01 without smoking halt). The results show that measures to improve oxygen transport capacity, such as blood transfusion or oxygen breathing, are indicated early, especially in an emergency, in smokers and those with uncertain smoking habits. Smoking halt of at least nine hours should be recommended to all heavy smokers before elective surgery.
Adult↗
[Carbomonoxyhemoglobin and methemoglobin in patients with and without a smoking history during ambulatory anesthesia. Consequences for the use of pulse oximetry].
Carboxyhemoglobin (COHb) and methemoglobin (MetHb) in venous blood were determined by oximetry in 1000 non-hospitalised preoperative patients. 370 of them were smokers (S), 630 non-smokers (NS). In addition, in five S we compared the oxygen saturation measured by pulse oximetry (SaO2, p) with that measured by in vitro oximetry (SaO2) and that calculated with reference to COHb (SaO2,korr). MetHb (0.66 +/- 0.21%, mean +/- standard deviation) was found to be of no relevance. COHb in S (5.12 +/- 2.25%, maximum 12.4%) was significantly higher than in NS (1.82 +/- 0.3%, range 0.9%-4.0%) and is therefore of importance in S for the oxygen transport and for the interpretation of SaO2, p, which overestimated SaO2 at a COHb level of 4.4 +/- 0.7% by 4.5 +/- 0.9%. The difference between SaO2, korr (calculated according to Forstner) differed from SaO2 by 0.66 +/- 0.5% only. We conclude that there is an indication for in vitro oximetry in non hospitalised smokers or cases of unknown smoking history. If oximetry is not available, both a reduction of O2-binding hemoglobin and an overestimation of SaO2 by pulse oximetry in an order of ten per cent should be taken into account. To compensate for dyshemoglobin fractions, pulse oximetry using more than two wavelengths is desirable.
Ambulatory Care↗
[Transvenous digital subtraction angiography of the thoracic aorta after surgical correction of isthmic stenosis].
25 patients (normotensive n = 19, hypertensive n = 6) underwent DSA control following corrective surgery of a coarctation of the thoracic aorta to exclude vascular complications. Simultaneously pressure gradients were determined between upper and lower extremities using the doppler-sonography. DSA was diagnostic in all patients. 2 cases showed a patch-dependent dilatation, in 1 case an anastomotic aneurysm could be demonstrated. In 6 patients with hypoplastic aortic arch and 2 patients with a slight reduction of the diameter in the anastomotic region a pathological pressure-gradient was measured. In these patients the ratio of aortic arch rsp. anastomosis/descending aorta was reduced in diameter (less than 0,66) and area (less than 44). Hypertension could not be related to pressure gradients or vascular disorders.
Adolescent↗