Central venous catheter placement: comparison of the intravascular guidewire and the fluid column electrocardiograms.

BACKGROUND AND OBJECTIVE: Placement of central venous catheters in patients is associated with several risks including endocardial lesions and dysrhythmias. Correct positioning of central venous catheters in the superior vena cava is essential for immediate use. The objective of a first study was to evaluate the signal quality of an intravascular electrocardiogram (ECG) during position control using a guidewire compared with the customary fluid column-based ECG system, and to assess its efficacy of correct placement of the central venous catheter. A second study tested if dysrhythmias can be avoided by intravascular ECG monitoring during catheter and guidewire advancement. METHODS: The jugular or subclavian vein of 40 patients undergoing heart surgery or who were being treated in the intensive care unit was cannulated. Intravascular ECGs were recorded during position control, and guidewire and water column lead were compared in the same patient with regard to the quality of the ECG reading and P-wave enhancement. In another 40 patients, the guidewire was inserted only 10 cm and the central venous catheter advanced under guidewire ECG control. Correct position of all the central venous catheters was confirmed by chest radiography. RESULTS: All central venous catheters were correctly positioned in the superior vena cava. For the same catheter position, the P-wave was significantly larger in the guidewire ECG than in the fluid column system. No changes in the quality of the ECG were detected when the guidewire was advanced or withdrawn by 1 cm relative to the catheter tip. Cardiac dysrhythmias were not seen during ECG-monitored advancement of the guidewire. CONCLUSIONS: ECG quality using a guidewire lead is superior to the water column-based system. Furthermore, it is independent from the exact position of the guidewire as related to the tip of the catheter. Using intravascular guidewire ECG during advancement can prevent induction of dysrhythmias.

[Experimental principles and general practice of intraoperative autotransfusion with blood irradiation in tumor operation]. / Experimentelle Grundlagen und Praxis der intraoperativen Autotransfusion mit Blutbestrahlung bei Tumoroperationen.

Clinical studies fail to verify or to exclude the lethal risk of tumor spread after intraoperative autotransfusion in tumor surgery. An alternative approach is the development of methods for the elimination of tumor cells in the salvaged blood. The radiosensitivity of tumor cells especially in oxygenated single cell suspensions is well known, while the non-nucleated red blood cells are radioresistant. With 50 Gy a 12 log reduction in proliferating cells is expected. This we have tested experimentally and put into clinical practice. The suppression of colony formation in cell culture by irradiation with 50 Gy was tested with tumor cells from established cell lines or from solid tumors after admixture in high cell number to red blood cells from volunteer blood donations. DNA metabolism was tested by incorporation of bromodesoxyuridine (BrdUrd) and staining with mcab-anti-BrdUrd. Colony formation and DNA metabolism was absent in all samples of cell lines or tumor cells in blood after irradiation with 50 Gy, reflecting a 10 log, or 7 log reduction, respectively. In clinical practice the method of intraoperative blood salvage during tumor surgery with blood irradiation showed its practicability and efficacy in reducing homologous transfusions.

[Irradiation of wound blood from tumor surgery for retransfusion]. / Die Bestrahlung von Wundblut aus Tumoroperationen zur Retransfusion.

Intraoperative autotransfusion is contraindicated in tumor surgery because of the danger of tumor cell dissemination. We have tested the elimination of tumor cells in blood by irradiation for safe retransfusion. Tumor cells of various origin were mixed to washed red blood cells from volunteer blood donations. The blood was irradiated with 50 Gy. After isolation of the tumor cells by density gradient centrifugation they were tested for colony formation. While with different tumor cell lines (n = 12) 10 cells were sufficient to yield several colonies, as many as 10(10) cells did not result in any colony after irradiation of the blood. Similar results were obtained with cells cultured from blood salvaged during tumor surgery (n = 3), and with tumor cells prepared from various carcinomas (n = 10). Flow cytometric DNA analysis showed the irradiated cells in mitotic arrest. None of these cells had residual DNA metabolism expressed as incorporation of BrdUrd. We were able to demonstrate a rate of reduction in dividing cells of up to 10(9). With the typical irradiation sensitivity of tumor cells, with D0 values between 1 and 2 Gy, a dose of 50 Gy results in an effective log 12 reduction, sufficient for safe elimination of tumor cells found in shed blood. No adverse effects of the gamma-irradiation on the blood cells are to be expected, especially since the blood is retransfused without storage.

[The rate of injection of succinylcholine and onset of neuromuscular action, serum potassium or myoglobin levels. Studies in men during halothane anesthesia]. / Injektionsgeschwindigkeit von Succinylcholin und neuromuskulärer Wirkungseintritt, Serumkalium- bzw. -myoglobinkonzentration. Untersuchungen bei Männern in Halothannarkose.

Succinylcholine was injected at different speeds to 60 men in halothane anesthesia, to see whether the rate of injection influenced the effects. METHODS. Sixty men (ASA I and II, mean age 28.6 years) undergoing surgery without muscle trauma were studied. They were treated uniformly with respect to premedication, anesthesia, venipuncture (cubital), and concentration (1%) and dosage (1 mg/kg) of succinylcholine (SCh). The only difference lay in the speed of injection of the relaxant: 20 mg/s, 8 mg/s, 4 mg/s, 2 mg/s and 1 mg/s, 12 patients being randomly allocated to each. The injection rate was controlled by a preprogrammed microprocessor pump system (XD 5500, HC Ulrich, D-7900 Ulm, Donau). The neuromuscular transmission was monitored by the adductor pollicis twitch technique using indirect supramaximal stimulation (Accelograph, biometer, DK-5120 Odense). The recorded twitch response allowed determination of the total onset time (TOT) from the beginning of the injection to the maximal twitch depression, its components, latent and manifest onset times (LOT and MOT), and the twitch depression factor ki. Blood samples for measurement of potassium and myoglobin levels (RIA, sensitive to 5 ng/ml) were taken before and 5, 15, and 30 min after SCh administration. For determination of the course (difference between two values before and after SCh), the maximum level up to 30 min was recorded. RESULTS. The twitch depression amounted to 100% in 57 patients and to 93% or 98% in the remaining 3. Reducing the speed of injection led to significant prolongation of TOT and LOT (Table 3) and significant differences in the onset characteristic in regard to twitch depression factor ki (Table 4). No significant influence on the increase in potassium (Table 7) and myoglobin (Table 8) was observed. CONCLUSION. These findings give no cause to inject SCh more slowly than usual in healthy adults.