Biomedical subjects

F O Mertzlufft

Publications and source records attributed to F O Mertzlufft.

5 recordsLinked to original sources

PubMed1989

Arterial and mixed venous blood gas status during apnoea of intubation--proof of the Christiansen-Douglas-Haldane effect in vivo.

The Christiansen-Douglas-Haldane effect, in short the Haldane effect, describes the dependence of the CO2 binding of blood on the degree of oxygenation of haemoglobin. Under the physiological conditions of an 'open' system between blood and alveoli the partial pressure of arterial CO2 (PaCO2), must be less than that of mixed venous blood (PvCO2). During the unphysiological conditions of a 'closed' system, e.g. hyperoxic apnoea, i.e. continuous oxygen uptake without CO2 delivery by the lungs, the PaCO2 will not only approximate the PvCO2 but will even exceed it. Without the Haldane effect, rapid adjustment of PaCO2 to PvCO2 would be expected during apnoea due to the lack of CO2 excretion. If, however, as undertaken in this study, ongoing oxygenation (high alveolar PO2 (PACO2) with concomitant lack of CO2 delivery (apnoea, i.e. the CO2 concentration remains constant) lead to a continuing sufficient oxygenation of blood during its passage through the lung capillaries, then this leads to a rightwards shift of the CO2 binding curve--the Haldane effect. The resulting increase in PCO2 as shown here actually leads to an arterial-mixed venous CO2 partial pressure difference (avDPCO2) of 2.8 +/- 1.8 mmHg. The results described substantiate for the first time the existence of the Haldane effect under clinical conditions.

Apnea↗

PubMed1989

[The use of pulse oximetry in detecting disorders of the arterial oxygen status in the immediate postoperative phase exemplified by combination anesthesia with isoflurane].

Adequate respiratory monitoring should immediately indicate deteriorations of arterial oxygen status, e.g. hypoxia (paO2-decrease [mmHg]), hypoxaemia (caO2-decrease [ml/dl]) and hypoxygenation (saO2-decrease [%]). These alterations have been detected in the early postanaesthetic period only by the classical clinical criterias cyanosis and tachycardia. Therefore, O2-application often is recommended for the first 10 min postoperatively. Nevertheless oxygen therapy as well as discharge from the recovery room both are dependent on the anaesthetist's judgement. It was the aim of this study to evaluate incidence and criterias of postanaesthetic hypoxygenation following balanced anaesthesia with isoflurane and to estimate both the actually most valid parameter (psO2) and the monitoring of choice (pulse oximetry). Postoperative hypoxygenation (psO2 less than 90%) occurred in 36% within the total of 50 patients. A correlation between hypoxygenation and sex, age, smoking habits and ASA-classification (groups I and II) could not be detected. In conclusion postanaesthetic hypoxygenation must be considered as being influenced by a widespread number of different factors. It's occurrence therefore, seems to be unpredictable. Hypoxygenation can easily be avoided by application of O2 (31/min) over at least 40 min. Cyanosis and tachycardia are not suitable for recognition of hypoxaemia caused by periodically occurring hypoxygenations. With respect to the limitations of the method (measurement of arterial O2-saturation in peripheral circulation using pulse wave as an inflow indicator of arterial blood into the capillary bed; increased Hb-derivative concentrations, e.g. COHb), pulse oximetry for estimation of partial O2-saturation (psO2) seems to be the respiratory monitoring of choice in the early postoperative period. In that sense it is superior to pO2 but inferior to saO2 and caO2.

Adult↗

PubMed1989

[Monitoring critically ill patients during transport by helicopter using a patient with abdomen apertum as an example].

Noninvasive continuous monitoring systems are newly emerging as an important means of monitoring during transports in emergency care, e.g. transportation by helicopter. While automatic oscillometric blood pressure monitors have been used in the perioperative area for some time, a similar development can be observed in the field of emergency care and transportation with the availability of light, portable and battery operated systems. For monitoring adequate oxygenation, pulse oximeters have recently been brought into discussion for both the perioperative period and the transport of critically ill patients. In contrast to well-established monitoring techniques during helicopter transports (ECG, inspection, manually measured blood pressure (BP), pulse oximetry reveals an oxygen deficiency due to respiratory and cardiocirculatory problems, enabling precious time to be saved. This concept is illustrated during the helicopter transport of a critically ill patient with abdomen apertum caused by Clostridium perfringens infection. Even with a critical look at the already described mishaps of this method--e.g. overestimation of true O2 saturation (sO2) and additional overestimation caused by Hb-derivatives--pulse oximetry was found to be superior to the established monitoring techniques. Furthermore, oscillometric blood pressure detection was very satisfactory during the 30-min helicopter transport. Based on our results, we believe pulse oximetry and automatic oscillometric BP-measurement to be useful for monitoring during transports in helicopters, thus improving patient safety.

Abdomen↗

PubMed1988

[In vivo detection of the Christiansen-Douglas-Haldane effect in clinical conditions].

The Christiansen-Douglas-Haldane effect, also termed Haldane effect, describes the dependence of CO2 absorption by blood on the degree of hemoglobin oxygenation. Under the physiological condition of an "open" system between blood and alveolus, the arterial partial pressure of CO2 (paCO2; mmHg) must range below the mixed-venous (pvCO2; mmHg) value. During the nonphysiological situation of a "closed" system, e.g. hyperoxic apnea after adequate pre-oxygenation (O2 uptake with lack of CO2 delivery), paCO2 can assimilate to pvCO2 and even exceed it. The remainder has often been termed a "paradoxical phenomenon". It was the aim of this study to prove the Haldane effect in vivo in the "closed" system of hyperoxic apnea. Eighty patients (ASA II-IV, NYHA II-III) scheduled for coronary surgery gave written informed consent and were examined. Following the preparations for induction (venous and arterial cannulas, pulmonary artery catheter), they were pre-oxygenated with 6 l O2/min until induction of anesthesia was achieved. Pre-oxygenation was maintained actively/passively until intubation. At the onset and the end of intubation the arterial (a) and mixed-venous (v) blood gas status (pHa, pHv, saO2 and svO2 (%), paO2 and pvO2, paCO2 and pvCO2 were determined using the Corning 170 pH/blood gas analyzer and the Corning 2500 CO-oximeter. Statistical analysis of the data was based on Student's t-test for paired samples. Periods of apnoea ranged between 60 and 180 s. The data were allocated to three groups, depending on the duration of apnea: Group I: 60-100 s; Group II: 101-140 s; Group III: 141-180 s.(ABSTRACT TRUNCATED AT 250 WORDS)

Apnea↗

PubMed1987

Correlation coefficients in human skulls: significant sexual differences.

This study of 500 male and female skulls proves: significant differences of correlation coefficients (p less than or equal to 0.01) occur between the two sexes. The combined variables are: 1. bizygomatic breadth (45)/skull base length (5) 2. bizygomatic breadth (45)/foramen magnum length (7) 3. bizygomatic breadth (45)/foramen magnum breadth (16) 4. bizygomatic breadth (45)/basion-bregma height (17) 5. foramen magnum breadth (16)/skull base length (5) Female skulls have generally higher correlation coefficients values than males which is interpreted as an indication of homogeneous growth.

Cephalometry↗