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Biomedical subjects

B Brismar

Publications and source records attributed to B Brismar.

At least 109 records · Page 6Linked to original sources

Densities in dependent lung regions during anaesthesia: atelectasis or fluid accumulation?

In previous studied with computed tomography (CT) prior to and during general anaesthesia, we found that densities developed in dependent parts of the lungs immediately after induction of anaesthesia in all examined patients. It was suggested that the densities were atelectases created by compression of lung tissue but an alternative explanation could be accumulation of extravascular fluid in the lung tissue and/or in the pleural space. In the present study the nature of the densities was analysed in further detail. Injections of contrast medium into the pleural space revealed that the densities were located in the lung tissue and not in the pleural space. By injecting contrast medium intravenously and repeating the CT scanning over a 2-min period the passage of contrast through the major vessels and the lung densities could be studied. The transit time of the contrast medium was of the same magnitude in the densities and the major lung vessels. This indicates that there were no regions with an increased amount of extravascular fluid to delay the contrast passage. These findings oppose the idea of fluid accumulation as the cause of the densities, while atelectasis remains the most plausible explanation.

Adult↗

Splanchnic blood flow during halothane-relaxant anaesthesia in elderly patients.

We have previously found that halothane-relaxant anaesthesia in elderly patients causes a change towards a hyperkinetic circulation, with a decrease in the arterial-mixed venous oxygen content difference. This could be attributed to vasodilation. In the present study the splanchnic contribution to these changes was investigated. Nine patients were studied during halothane-relaxant anaesthesia prior to surgery. During anaesthesia splanchnic blood flow was markedly reduced, while splanchnic oxygen uptake decreased only moderately compared with the awake level. This resulted in an increase in splanchnic oxygen extraction. It is concluded that the splanchnic vascular bed does not contribute to the "hyperkinetic" circulation during halothane anaesthesia.

Aged↗

Stomach rupture following ingestion of sodium bicarbonate.

Spontaneous rupture of the stomach is an uncommon condition with a usually poor prognosis. The rupture occurs as a result of a closed loop obstruction with increased pressure against the stomach wall. A case of stomach rupture occurring after hyperdistention of the stomach following ingestion of sodium bicarbonate is described and the pathophysiological mechanism is discussed.

Adult↗

The significance of bacteriological findings at cholecystectomy.

The value of routine bacterial culture and gram staining of bile intraoperatively was investigated in 84 patients undergoing cholecystectomy. A positive bile culture was found in five of eight patients with an acute cholecystitis and in three of five patients with stones in the common bile duct, but in only nine of 66 patients with chronic cholecystitis without a common duct stone (14%). None of the patients with a normal gallbladder wall or cholesterolosis were bacteria-positive. Immediate microscopy of bile showed positive results in eight of 17 culture-positive bile specimens. As the majority of strains isolated from bile were aerobes sensitive to ampicillin and trimethoprim-sulphamethoxazole, any of these antibiotics can safely be administered intraoperatively to patients belonging to the risk group (acute cholecystitis, common bile duct stone). Immediate microscopy of bile is an unrealiable method of limited value and is not recommended for routine use.

Adult↗

The catecholamine concentration in central veins of hypertensive patients--an aid not without problems in locating phaeochromocytoma.

The concentrations of adrenaline, noradrenaline and cortisol in blood sampled at routine attempts at catheterization of the adrenal and renal veins, the inferior vena cava and the azygos and hepatic veins were measured in six patients with a phaeochromocytoma and six patients with hypertension due to other causes. In the non-tumour patients the adrenaline and noradrenaline concentrations, compared with normal values for peripheral venous blood, were abnormally high in five out of seven samples from the site of the left adrenal vein but in only one out of seven from the right side. In all the adrenal vein samples with an abnormally high catecholamine concentration the cortisol level was also elevated, and it was at least 100 per cent higher than in samples from the inferior vena cava. This suggests that a high catecholamine concentration linked with an elevated cortisol level is merely an indication of correct adrenal vein sampling and is not necessarily evidence of a tumour. In successful attempts of sampling adrenal venous blood (cortisol levels increased), concentrations of adrenaline and noradrenaline of up to 100 and 20 nmol/l, respectively, can be regarded as normal. From a retrospective analysis of catecholamine levels in the six tumour patients it is clear that owing to the variability of venous drainage from the right adrenal gland, the technique of adrenal venous blood sampling may be unreliable and even misleading in attempts to locate a phaeochromocytoma. This is also true in patients with generally elevated catecholamine levels.

Adrenal Gland Neoplasms↗

The ambulance helicopter is a prerequisite for centralised emergency care.

During the summer seasons of 1978-1983 (56 weeks), trial activity with a physician-manned ambulance helicopter was carried out in the County of Stockholm (population 1.5 million). The area includes an extensive archipelago. Within the region there are 11 large general hospitals, three of which are supplied with a helicopter pad. During the trial period 1 246 helicopter missions were undertaken, of which 943 resulted in emergency transportation of the patient (83% by helicopter, 17% by ambulance). The number of missions per day varied from 0-11, with a mean number of 3.2. The turn-out time from receipt of the call to arrival at the scene of the accident or illness was less than 30 minutes in 75% of the cases. Of the emergency calls, 57% involved cases of illness and 43% accidents. Therapeutic intervention by doctors at the scene was considered to have been of vital importance in 22% of the cases, desirable in 28% and unnecessary in 50%. This intervention was regarded as life-saving in 18 cases (2%). By special training of emergency call operators, the number of unnecessary helicopter missions could be minimised (9% of all missions). To continuing specialisation and centralisation of emergency care with extended catchment areas, demands an advanced transport system. This trial has shown that through the use of a physician-manned ambulance helicopter the emergency care within the region can be centralised with retention of adequate turn-out times.

Aircraft↗

Impact of cefbuperazone on the colonic microflora in patients undergoing colorectal surgery.

Cefbuperazone was given intravenously in a dose of 1 g at induction of anaesthesia, followed by a subsequent dose of 1 g 12 h after the first dose, to 10 patients undergoing colorectal surgery. A series of serum and faecal specimens were taken for analysis of cefbuperazone concentrations. Tissue samples from the gut wall were taken at surgery. The maximum serum concentrations (mean value 98.6 +/- 9.1 mg/l) during surgery were reached 30 min after cefbuperazone administration. The cefbuperazone concentration in the tissue samples varied between 7.3 and 40.5 mg/kg and the concentration in the faecal samples between 0 and 27.0 mg/kg. Faecal samples were also collected during the investigation period for cultivation of aerobic and anaerobic bacteria. The aerobic bacteria--streptococci, enterococci and enterobacteria--were suppressed significantly during the prophylaxis period. Among the anaerobic bacteria, cocci, bifidobacteria, eubacteria, lactobacilli, clostridia, fusobacteria and bacteroides decreased markedly during the same period. After four weeks the microflora was normalized in all patients. No postoperative infections occurred.

Adult↗

Functional residual capacity, thoracoabdominal dimensions, and central blood volume during general anesthesia with muscle paralysis and mechanical ventilation.

Functional residual capacity (FRC), rib cage and abdominal dimensions (rc-ab), central blood volume (CBV), and extra vascular lung water (EVLW) were measured in six lung-healthy subjects awake and during halothane anesthesia, muscle paralysis, and mechanical ventilation. FRC was assessed by multiple breath nitrogen washout, rc-ab dimensions by computerized tomography, and CBV and EVLW by a double-indicator dilution technique (thermo-dye). During anesthesia, FRC decreased by 0.5 1 (17%). The cross-sectional chest area was reduced by 12-20 cm2, causing an approximate reduction in thoracic volume by 0.3 1. Concomitantly, the diaphragm was moved cranially by an average of 1.9 cm, diminishing the thoracic volume a further 0.5 1. The abdominal cross-sectional area did not alter significantly, despite the shift of the diaphragm. CBV decreased by 0.3 1. EVLW did not change significantly. It is concluded that the thoracic volume is reduced during halothane anesthesia, muscle paralysis, and mechanical ventilation as a result of cranial shift of the diaphragm and reduction in transverse area. The decrease in thoracic volume is accompanied by a reduction in FRC and a displacement of blood from the thorax to the abdomen, the transverse area of the latter thus being maintained despite the shift of the diaphragm.

Abdomen↗

Pulmonary densities during anesthesia with muscular relaxation--a proposal of atelectasis.

Twenty patients (23-76 yr) were studied with regard to lung tissue changes prior to and following induction of general anesthesia with muscular relaxation, and another four subjects were studied for a longer period awake. The transverse thoracic area and the structure of the lung tissue were determined by computerized tomography. No abnormalities in the lung tissue were noted before anesthesia. Within 5 min after induction, including muscular relaxation, all subjects had developed crest-shaped changes of increased density in the dependent regions of both lungs. They were largest in the most caudal segment (4.8 +/- 0.8% of the transverse lung area, mean +/- SE) and smaller in the cephalad exposures (3.4 +/- 0.7% of the transverse area). The size of the densities showed no correlation to age. The densities did not increase after a further 20 min of anesthesia and were not affected by the inspiratory oxygen fraction. When the subjects were moved from the supine to the lateral position, the crest-shaped densities disappeared in the nondependent lung and remained in the dorsal part of the dependent lung. The application of positive end-expiratory pressure of 10 cmH2O eliminated or reduced the densities. The four awake subjects showed no lung densities after 90 min in the supine position. It is suggested that these crest-shaped densities represent atelectases, which develop by compression of lung tissue rather than by resorption of gas.

Adult↗

Halothane-relaxant anaesthesia in elderly patients.

Twenty-three elderly patients, scheduled for elective cholecystectomy, were studied during halothane-relaxant anaesthesia. Anaesthesia was induced with thiopentone and maintained with halothane in 12 patients, six of whom had also received premedication. Eleven patients were anaesthetized with halothane, without thiopentone induction and with no premedication. Measurements of central haemodynamics were performed awake and during anaesthesia at end-tidal halothane concentrations of 0.5 and 1.0%; at the lower concentration, measurements were also made after addition of nitrous oxide. Premedication and thiopentone had no influence on the subsequent halothane anaesthesia. Halothane caused reductions of cardiac index, mean arterial blood pressure and oxygen uptake. However, neither right atrial nor pulmonary capillary venous pressure increased and the arterio-venous oxygen content difference decreased. These findings differ from those made by others in younger subjects and are probably attributable to a dose-dependent reduction in systemic vascular resistance. The addition of nitrous oxide had only minor effects on central circulation. The results suggest that the age of the patients influences their reaction to halothane anaesthesia.

Aged↗

New aspects on atelectasis during anaesthesia.

Sixteen subjects were studied with regard to lung tissue changes during general anaesthesia. The transverse area and the structure of the lung tissue were studied by computerized tomography. No abnormalities were noted in the lung tissue before anaesthesia, but within five minutes after induction, all subjects had developed crest-shaped dependent changes of an increased density in both lungs. They correspond to 4 - 5 per cent of the total transverse area. The size of the densities could not be correlated to the age of the subjects, or time of the anaesthesia, and they were not affected by the inspiratory oxygen fraction. They could be rotated by turning the patient, and the application of a positive end-expiratory pressure eliminated or reduced the densities. It is suggested that the densities are atelectases, which develop by compression of lung tissue, and not by gas resorption.

Aging↗

What causes the lowered FRC during anaesthesia?

Functional residual capacity (FRC) by means of body plethysmography chest-abdomen dimensions by whole body computerized tomography, central blood volume (CBV) by double-indicator dilution technique and extremity (peripheral) blood volume (PBV) by segmental thigh and upper arm plethysmography, were assessed in lung-healthy patients who were to undergo general anaesthesia and elective surgery. Anaesthesia was induced by thiopentone and was maintained either by a continuous drip of thiopentone or by inhalation of halothane. Muscle relaxation was obtained by pancuronium bromide. Anaesthesia caused a reduction of the total thoracic volume by an average of 0.75 1. This followed from a cranial shift of the diaphragm and to less extent by a reduced transversal chest area. FRC was concomitantly reduced by an average of 0.5 1 and the CBV, mainly thoracic blood, was reduced by 0.25 - 0.3 1. PBV was slightly reduced by 0.1 1, and it is concluded that these fractions of CBV and TBV must have been pooled in the abdomen. This pooling resulted in more or less maintained transversal abdomen area despite the cranial shift of the diaphragm.

Anesthesia, General↗

Ambulance utilization in Sweden: analysis of emergency ambulance missions in urban and rural areas.

Data concerning ambulance utilization in a rural and an urban region were registered in a computer. In both regions approximately 30% of missions were emergencies. In the urban area, 20% of the emergency missions were due to trauma, compared with 10% in the rural area (P less than .01). The major symptoms were unconsciousness (34%) and shortness of breath (24%) in the rural region, while in the urban region pain (32%) was the dominating symptom. The response time in emergency missions, used as a measure of the service level of the emergency medical system, was shorter in the urban area than in the rural area (P less than .01): less than 15 minutes in 93% of emergencies in the urban area (mean time, 8.1 minutes) and in 78% of emergencies in the rural area (mean time, 10.2 minutes). Ambulance utilization was higher (P less than .01) in the urban region (0.37 missions/ambulance/hour) than in the rural region (0.22 missions/ambulance/hour). The study indicates that there are great differences between urban and rural areas with respect to the incidence and character of ambulance missions. This difference must be considered when analyzing the cost effectiveness of emergency medical services.

Ambulances↗

Training of emergency dispatch-center personnel in Sweden.

The ability to recognize symptoms, to make priority decisions, to dispatch suitable ambulance transport and inform the crews, and finally, to initiate first aid via the caller is essential for optimum care of severely injured or ill patients outside the hospital. In Sweden, a special job-related course trains dispatch-center personnel to think in terms of symptoms and evolution of the victim's status, and to assess the level of seriousness.

Allied Health Personnel↗

Oxygen uptake and central circulation during ketamine anaesthesia.

Cardiac output, oxygen uptake and plasma catecholamines were studied in patients when awake and during ketamine anaesthesia prior to and during upper abdominal surgery. Oxygen uptake was determined by using a masspectrometer and cardiac output was measured according to the Fick principle. Plasma catecholamines were analysed by high performance liquid chromatography. Stroke volume had fallen by 27% while heart rate had increased after 15 min of anaesthesia, maintaining cardiac output at the awake level. Concomitantly, the oxygen uptake had fallen by 18%. During the succeeding hour of anaesthesia and surgery, cardiac output displayed a transient decrease and oxygen uptake returned to the awake value. The plasma adrenaline concentration fell during the initial phase of anaesthesia and then returned to the awake level. The noradrenaline concentration was increased during the whole anesthetic period. The data suggest a relationship between oxygen uptake and cardiac output during ketamine anaesthesia, similar to that seen during neurolept-nitrous oxide and halothane anaesthesia, except for the initial hyperkinetic period following the induction. No relationship could be shown between catecholamine concentrations in plasma and the central haemodynamics.

Abdomen↗

Postoperative lymphoedema after treatment of breast cancer.

A clinical study was made of the occurrence of lymphoedema of the arm following radical mastectomy and modified radical mastectomy for curable breast cancer. The relation between this incidence and the occurrence of axillary node metastases and subsequent radiation to the axilla was examined. Both radical surgery and radiation increased the risk of postoperative arm lymphoedema. By changing the surgical approach towards less extensive operations this risk has been substantially reduced while radiation therapy still implies a high risk for persistent lymphoedema.

Arm↗

Head injury and intoxication: a diagnostic and therapeutic dilemma.

One hundred patients admitted to a surgical clinic with a diagnosis of concussion of the brain were studied regarding the abuse of alcohol and narcotic drugs. 58% of the patients were assessed as intoxicated on admission. Psychiatric evaluation revealed a history of alcohol dependence in 43 of the patients and experience of narcotic drugs in 25. Forty-six of the patients reported recurrent defects of memory and nine suffered from epilepsy. Amnesia therefore seems to be a factor of limited diagnostic value in concussion of the brain. Because of diagnostic difficulties, in patients with alcohol intoxication a more liberal attitude towards cranial X-ray and CT-scanning will be justified. Blood ethanol determination, measurement of blood gamma glutamyl transpeptidase and the mean blood corpuscular volume are clinically important to elucidate the etiology in patients with head injury. Active rehabilitative measures should be initiated in collaboration between the surgeon, psychiatrist and social worker to prevent post-concussional syndromes.

Adult↗