Ambulatory pressure gradient in the veins of the lower extremity.

BACKGROUND: Neovascularization is an important cause of venous reflux recurrence after high ligation of the long saphenous vein. The pathogenesis of this phenomenon is so far obscure. It is possible that a hemodynamic factor--a pressure gradient between the femoral vein and the residual long saphenous vein--could be the trigger initiating the process of neovascularization. PATIENTS AND METHODS: Venous pressure measurements on eight patients with primary varicose veins were performed in the erect position in the insufficient long saphenous vein on the thigh. Mean pressures in the quiet standing position and ambulatory pressures were considered. By interrupting the saphenous reflux either distally or proximally to the point of measurement the pressure conditions either in the femoral or in the crural veins were simulated. RESULTS: With the tourniquet placed distally to the point of measurement, the venous pressure in the upper interrupted segment of the long saphenous vein (equivalent to the pressure in the femoral vein) remained uninfluenced during ambulation. In contrast, by interrupting the reflux proximally to the point of measurement, a marked decrease of the ambulatory pressure in the lower part of the long saphenous vein (equivalent to the pressure in the crural veins) was noted. CONCLUSIONS: A pressure difference occurs between the veins of the thigh and the lower leg during the activation of the muscle venous pump. This fact may explain the tendency of recurrencies of varicose veins after high ligation of the long saphenous vein as well as the initiation of reflux.

Operations on patients deemed "unfit for operation and anaesthesia": what are the consequences?

BACKGROUND: The decision "patient unfit for anaesthesia and operation" is likely to cause a delay of the scheduled operation. This retrospective evaluation was done: 1) to determine the correctness of preoperative tentative diagnoses of coexisting diseases making anaesthesia and operation excessively risky in relation to the physician's training status; 2) to examine the question of whether preoperative medical management modified according to the anaesthesiologist's suggestions had a positive impact on the perioperative course. METHODS: The medical records of patients scheduled for elective non-cardiac surgery who were rated "unfit for operation and anaesthesia" were evaluated. The accuracy of the tentative diagnoses was examined for relation to the training status of the anaesthesiologists. The preoperative management was tested for its impact on postoperative outcome. RESULTS: During the observation period 16,122 patients underwent preoperative anaesthesiological assessment; 1021 (6.3%) were initially considered to be unfit for operation and anaesthesia. The records of 807 patients were available for review. The accuracy of the tentative diagnoses was 70%, and was not significantly affected by the training status of the physicians (P = 0.022). Four hundred and seventeen patients were excluded from the second part of the investigation (discharged without operation, underwent operation using local anaesthesia or tentative diagnosis not confirmed). Three hundred and ninety patients were operated under general anaesthesia. Group I (n = 216) was managed according to the anaesthesiologist's suggestions and was found to have a significantly lower complication rate (18.1%) than group II (n = 174) in which the suggestions from the preoperative assessment were ignored (32.2%; P < 0.05). The perioperative mortality rate in group I was 2.3% compared with 5.2% in group II (n.s.; P > 0.05). CONCLUSIONS: We conclude that the anaesthesiology decision "patient unfit for operation and anaesthesia" has a high accuracy, independent of the anaesthesiologist's training status, and that preoperative medical management significantly reduces complications.

A comparison of the end-tidal-CO2 documented by capnometry and the arterial pCO2 in emergency patients.

Satisfactory artificial ventilation is defined as sufficient oxygenation and normo- or slight arterial hypocarbia. Monitoring end tidal CO2 values with non-invasive capnometry is a routine procedure in anaesthesia, emergency medicine and intensive care. In anaesthesia the ventilation volume is adjusted to the capnometric end tidal CO2 (ETCO2), taking into account a normal variation from the pACO2 of 3-8 mmHg. We evaluated the usefulness and practicability of using ETCO2 for correctly adjusting ventilation parameters in prehospital emergency care, by comparing arterial pCO2 and ETCO2 of 27 intubated and ventilated patients. We used the side-stream capnometry module of the Defigard 2000 (Bruker, ChemoMedica Austria) and a portable blood gas analyzer (OPTI 1, AVL Graz, Austria). Evaluation of the group of patients as a whole showed that there was no correlation whatsoever between the end expiratory and arterial CO2. Dividing the patients into three subgroups (1, During CPR; II, respiratory disturbances of pulmonary and cardiac origin; III, extrapulmonary respiratory disturbances), we found that only patients without primary cardiorespiratory damage showed a slight, but not statistically significant, correlation. This can be explained by the fact that almost any degree of cardiorespiratory failure causes changes of the ventilation-perfusion ratio, impairing pulmonary CO2 elimination. We conclude, that the ventilation of emergency patients can only be correctly adjusted according to values derived from an arterial blood gas analysis and ETCO2 measurements cannot be absolutely relied upon for accuracy except, perhaps, in patients without primary cardiorespiratory dysfunction.

Prehospital point of care testing of blood gases and electrolytes - an evaluation of IRMA.

BACKGROUND: This study evaluated the feasibility of blood gas analysis and electrolyte measurements during emergency transport prior to hospital admission. RESULTS: A portable, battery-powered blood analyzer was used on patients in life threatening conditions to determine pH, pCO2, pO2, sodium, potassium and ionized calcium. Arterial blood was used for blood gas analysis and electrolyte measurements. Venous blood was used for electrolyte measurement alone. During the observation period of 4 months, 32 analyses were attempted on 25 patients. Eleven measurements (34%) could not be performed due to technical failure. Overall, 25 samples taken from 21 patients were evaluated. The emergency physicians (all anesthesiologists) considered the knowledge of blood gases and/or electrolytes to be helpful in 72% of cases. This knowledge led to immediate therapeutic consequences in 52% of all cases. After a short training and familiarization session the handling of the device was found to be problem free. CONCLUSIONS: We concluded that knowledge of the patients' pH, pCO2 and pO2 in life threatening situations yields more objective information about oxygenation, carbon dioxide and acid-base regulation than pulse oximetry and/or capnometry alone. Additionally, it enables physicians to correct severe hypokalemia or hypocalcemia in cases of cardiac failure or malignant arrhythmia.