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Biomedical subjects

C Lennmarken

Publications and source records attributed to C Lennmarken.

At least 55 records · Page 3Linked to original sources
PubMed1990

Nitrogen requirements in severely injured patients.

The study was designed to evaluate nitrogen needs in severely injured patients during the first week after trauma. Thirty-nine patients aged from 18 to 65 years with a burn or fractures of more than two long bones were studied. Energy requirements were given parenterally as fat and glucose in isocaloric amounts. The patients were randomized into five groups receiving different amounts of nitrogen from zero to 0.3 g kg body-weight-1 24 h-1. Daily and cumulative nitrogen balance, urinary 3-methylhistidine excretion and nitrogen retention were calculated on days 2-8 after trauma. With no nitrogen, the mean(s.e.m.) daily nitrogen balance after the trauma was -13.8(0.5) gN. The balance improved markedly in groups with a nitrogen intake of up to 0.2 g kg body-weight-1 (P less than 0.001) compared with the no-nitrogen group. The 3-methylhistidine excretion increased because of the trauma in all groups with no statistically significant difference between the groups. Nitrogen retention decreased with increase in nitrogen supply and with time after injury. It is suggested that a nitrogen supply of 0.20 kg bodyweight-1 24 h-1 is optimal for severely injured patients during the first week after trauma.

Adolescent↗
PubMed1990

Assessment of peripheral blood flow using a pulse oximeter.

We investigated the bar graph on a pulse oximeter as an indicator of peripheral blood flow. Because blood flow is known to increase in the lower extremities during spinal analgesia, we chose patients receiving spinal analgesia as the experimental model. Although they are indirect indicators, we used laser Doppler readings and skin temperature to reflect peripheral blood flow. These measurements were made from each patient's foot and hand before and after spinal analgesia and were compared with the deflection on the pulse oximeter bar graph. After subarachnoid injection of bupivacaine, laser Doppler readings from the foot increased to 620 +/- 120% (P less than 0.05) of the control reading. The pulse oximeter signal amplitude increased from 5.2 +/- 0.4 to 9.4 +/- 0.3 bars (P less than 0.05) and mean skin temperature increased from 24.6 +/- 0.5 to 31.2 +/- 0.8 degrees C (P less than 0.05). No changes were noted in readings obtained from the hand. A Nellcor N-200 pulse oximeter may be used to evaluate the effect of sympathetic nerve block as indicated by an increase in peripheral blood flow.

Adult↗
PubMed1990

Effect of starvation on work capacity and voluntary skeletal muscle function in man.

Post-operative fatigue is a well-known clinical problem even after uncomplicated surgery. In the multifaceted post-operative state, several factors other then the surgical trauma may influence muscular function, such as an insufficient nutritional intake. The aim of this study was to investigate the effect of fasting on work capacity and voluntary skeletal muscle function. Eight healthy lean volunteers, age range 25-43 years, were studied the day before starvation, at the end of the fasting period of 5 days, and after another 3-4 days on a normal diet. Hand grip strength was assessed as maximum voluntary contraction (MVC) and physical working capacity was investigated with successively increased work load on a cycle ergometer until near exhaustion. After 5 days of total starvation, MVC remained unchanged but physical working capacity was reduced from 220 +/- 18 watt to 199 +/- 22 watt (p < 0.05). Corresponding heart rate, estimated effort and leg tiredness were not changed. A poor nutritional intake per se may therefore be a less important factor causing post-operative muscle fatigue than the operation itself.

Journal Article↗
PubMed1990

Use of post-tetanic count in assessment of a repetitive vecuronium-induced neuromuscular block.

In order to evaluate the use of the post-tetanic count (PTC) method during repetitive administration of vecuronium, we studied 20 patients allocated randomly to one of two groups: 10 patients received droperidol-fentanyl anaesthesia (control group); 10 other patients were given droperidol-fentanyl anaesthesia modified subsequently by addition of 0.5% isoflurane (isoflurane group). Before tracheal intubation, a bolus dose of vecuronium 0.08 mg kg-1 was given i.v. followed by repeated doses of 0.03 mg kg-1. The twitch response of adductor pollicis was recorded after supramaximal stimulation of the ulnar nerve at the wrist using a Myograph 2000 neuromuscular transmission analyser. In the control group, a close correlation was found between PTC and time to first reaction to train-of-four (TOF) nerve stimulation. This relationship was unchanged when comparing the bolus dose and each of eight consecutive maintenance doses. Further, the degree and the duration of intense block were unchanged after each of the eight maintenance doses. In the isoflurane group, the relationship between PTC and time to first reaction to TOF stimulation remained unchanged after addition of isoflurane. However, isoflurane caused a significant prolongation of the duration of intense block and a corresponding lower PTC in all patients. We conclude that PTC is a reliable method to evaluate intense neuromuscular block caused by vecuronium, even after repetitive administration of the drug and in combination with 0.5% isoflurane.

Adult↗
PubMed1990

Anaesthesia for cardioversion. A comparison between propofol, thiopentone and midazolam.

This study compares the induction and recovery characteristics, haemodynamic changes and side effects of propofol, thiopentone and midazolam when used as the anaesthetic agents for cardioversion. Recovery after midazolam was significantly longer (p less than 0.05) than with either thiopentone or propofol. There was no difference in the recovery times between thiopentone and propofol. There was a significant decrease in mean arterial pressure 2 minutes after induction with propofol and midazolam. Three patients each in the thiopentone and propofol groups needed assisted ventilation because of apneoea, and four patients each in the propofol and midazolam groups had low Spo2 values (less than 95%). Flumazenil was used to reverse the effects of midazolam in eight patients and five of these were still drowsy 4 hours after the procedure. This study indicates that thiopentone is the most satisfactory agent for anaesthesia for cardioversion.

Aged↗
PubMed1990

The influence of 10 mg and 20 mg of bambuterol on the duration of succinylcholine-induced neuromuscular blockade.

Bambuterol is an inactive prodrug which is enzymatically cleaved by plasma cholinesterase to yield the active compound, terbutaline. This catalytic process is accompanied by a selective inhibition of plasma-cholinesterase, the enzyme also necessary for the break-down of succinylcholine. We therefore studied the possible effect of bambuterol on succinylcholine-induced neuromuscular blockade in a double-blind fashion in patients undergoing surgery under general anaesthesia. Of the 39 patients studied, 13 patients had 10 mg of bambuterol, 12 had 20 mg and 14 were given placebo 10-16 h prior to anaesthesia. Succinylcholine 1 mg.kg-1 bw was administered after induction of anaesthesia. Following supramaximal train-of-four stimulation of the ulnar nerve, the tension developed in the adductor pollicis muscle was measured. Onset time and the durations of action (times to 10%, 25%, 75% and 90% recovery of the first twitch of the train-of four response) were recorded. The mean recovery times were prolonged 30-50% in patients who had received 10 or 20 mg of bambuterol as compared with placebo. It is concluded that a prolonged duration of action of succinylcholine can be expected in patients being treated with bambuterol.

Adult↗
PubMed1990

The clinical value of the haemoglobin concentration analysis (g/L) and the calculation of oxyhaemoglobin saturation (%) in an automatic blood gas analyser (ABL2, Radiometer A/S, Denmark).

This study was aimed to evaluate the accuracy and thereby the clinical value of the haemoglobin concentration (g/L) analysis and of the calculation of oxyhaemoglobin saturation (%) in a commonly used automatic blood gas analyser (ABL2, Radiometer A/S, Denmark). The measured and calculated values (ABL2) were compared to the readings obtained in a last generation haemoximeter (OSM3, Radiometer A/S, Denmark), which served as reference. The haemoglobin concentration measurements performed in the ABL2 apparatus showed an increasing underestimation of the true haemoglobin value at larger haemoglobin concentration values. This together with a poor correlation makes the analysis unsuitable for clinical use. The oxyhaemoglobin saturation values (%) obtained using the ABL2, however, had a good correlation to the corresponding values measured in the OSM3. It is suggested that the oxyhaemoglobin saturation value obtained in the ABL2 can be used clinically, e.g., for invasive control of pulsoximeters.

Arteries↗
PubMed1989

The effect of a fat emulsion on some common clinical chemical analyses.

During infusion of fat emulsion serum becomes turbid. Turbidity interferes in various photometric serum analyses delaying urgent therapeutic decisions. Small laboratories may lack access to an ultracentrifuge to clear turbid samples. To identify the analyses mostly disturbed we collected serum samples containing various concentrations of the compounds or activities commonly requested by the intensive care unit (ICU) and spiked the samples with Intralipid (Kabi Vitrum, Sweden). Glycerol measurements were used as estimate of the amount of Intralipid prevailing in turbid serum. Applying the common instruments Astra 8 (Beckman) and RA 1000 (Technicon) sodium, potassium, phosphate, calcium, creatinine, urea, total bilirubin, amylase, lactate dehydrogenase and albumin were not sensitive to interference. Magnesium and creatinine were slightly lowered whereas glucose was increased. Aspartate amino transferase was not measurable. We suggest (a), that ICU contact the clinical chemistry laboratory to clarify what analyses will be hampered by turbidity in the inhouse instruments; and (b), that high serum glycerol values may be indicative of erroneous results in these analyses; and (c) that charts with confidence limits be established to aid recognition of the magnitude and direction of the errors.

Journal Article↗
PubMed1989

The influence of 0.5% isoflurane on a vecuronium-induced neuromuscular blockade.

The influence of adding 0.5% isoflurane to a narcotic-based anaesthesia on the duration of effect and recovery time after repetitive administration of vecuronium was studied in ten healthy patients. The twitch response in the adductor pollicis muscle was recorded after supramaximal train-of-four (TOF) stimulation of the ulnar nerve at the wrist. Prior to endotracheal intubation a bolus dose of vecuronium (0.08 mg/kg b.w.) was given. During surgery repeated injections of vecuronium (0.02 mg/kg b.w.) were administered at a TOF ratio of 0.25. Hand-skin temperature, systolic blood pressure, end-tidal CO2 and isoflurane concentrations were continuously monitored. Before and after 90 min administration of isoflurane, the duration of effect was 21 +/- 4 and 24 +/- 5 min (mean +/- s.d., P less than 0.05) respectively. Corresponding recovery times were 270 +/- 60 and 280 +/- 70 s (n.s.). Skin temperature remained unchanged and systolic blood pressure showed only minor variations. The addition of 0.5% isoflurane to a narcotic-based anaesthesia causes a moderate increase in duration of effect but no change in recovery time from a repetitive vecuronium-induced neuromuscular blockade of 0.02 mg/kg.

Adolescent↗
PubMed1989

Clinical experience with atracurium during prolonged anaesthesia.

The pharmacodynamic properties of repeated injections of atracurium were studied in twenty-two patients. A control group received narcotic-based anaesthesia while another group received the same narcotic-based anaesthesia subsequently modified by the addition of 0.5% isoflurane. The twitch response of the adductor pollicis muscle was recorded after train-of-four (TOF) stimulation of the ulnar nerve at the wrist. Duration of effect and recovery time were measured. A bolus dose of atracurium (0.5 mg/kg b.w.) was given for tracheal intubation and maintenance doses of 0.2 mg/kg b.w. were given during anaesthesia at a TOF ratio of 0.25. Mean duration of anaesthesia was 7.5 hours (range 3-19). In the control group mean duration of effect and mean recovery time remained unchanged (six doses studied). A noteworthy inter-individual variation was found. In the isoflurane group mean duration of effect increased from 36.1 (SD 6.3) minutes to 42.2 (SD 8.1) minutes (P less than 0.05) following the addition of isoflurane. Corresponding recovery times remained unchanged. We conclude that during repeated administration of atracurium during narcotic-based anaesthesia, each patient shows a constant interval between requirements for maintenance doses of atracurium of 0.2 mg/kg b.w. Addition of 0.5% isoflurane causes a moderate prolongation of the duration of effect, but recovery time remains unchanged.

Adult↗
PubMed1988

Pulse oximetry during extradural analgesia for extracorporeal shock wave lithotripsy.

Exracorporeal shock wave lithotripsy (ESWL) may require immersion of the patient in water and extradural blockade for analgesia, which may both affect pulmonary and cardiovascular function and increase the likelihood of hypoxaemia. Twenty-four patients (ASA I-III) with extradural blockade and six healthy subjects were studied by pulse oximetry during immersion. Oxygen saturation (SaO2) tended to decrease after induction of extradural analgesia. Immersion decreased SaO2 further, by up to 2% in healthy volunteers (P less than 0.05) and 3% in patients (P less than 0.05). In two patients with arteriosclerosis, an SaO2 of 92% was accompanied by arrhythmias which resolved after administration of oxygen.

Adult↗
PubMed1988

Experience of multiple supplementary doses of vecuronium. Case report.

Seventy-one supplementary doses of vecuronium were used for muscle relaxation during a 22-h-long NLA II anaesthesia. For assessment of neuromuscular blockade, train-of-four stimulation was used to measure the twitch force of the adductor pollicis after electrical stimulation of the ulnar nerve. No cumulative effect of vecuronium could be demonstrated, measured under strictly controlled conditions. Adding isoflurane 0.5% (end tidal) only slightly prolonged the neuromuscular blocking effect.

Adolescent↗
PubMed1988

Should oxygen be administered after laparoscopy in healthy patients?

This study aimed to assess the oxygen flow necessary to maintain satisfactory oxygen saturation when administered via a nasopharyngeal catheter. Oxygen saturation was displayed by a pulse oximeter and/or measured in arterial blood samples. Thirty-six healthy women scheduled for elective diagnostic laparoscopy were anaesthetized using thiopentone, fentanyl and O2/N2O. Atracurium was used as relaxant which was reversed with atropine and neostigmine. Arterial samples were obtained prior to anaesthesia, on arrival in the postoperative ward and 1 h postoperatively. Oxygen saturation was monitored postoperatively using a pulse oximeter. The patients were randomly divided into three groups which received either no oxygen, 2 l O2/min or 4 l O2/min. On arrival in the postoperative ward 15% of the patients were below the normal limit of O2 saturation (94%). In patients receiving 2 l or 4 l O2, oxygen saturation was well above normal values. In patients receiving no oxygen, two had low oxygen saturation (92% and 93%). Comparing saturation values obtained in arterial samples with values measured with pulse oximetry gave r = 0.79. It is concluded that all patients should be given oxygen in the immediate postoperative period. Increasing oxygen flow from 2 to 4 l/min had no major effect on oxygen saturation. These results were obtained in healthy patients following minor abdominal surgery.

Adult↗
PubMed1988

Experience with vecuronium during long-lasting surgery.

Our knowledge of the possible cumulative properties of vecuronium is limited. Previous studies have shown a tendency towards an increased duration of effect, a slightly prolonged recovery time, as well as an increased variation in duration of effect. We have studied 15 patients scheduled for middle-ear surgery. During i.v. N2O-O2 anaesthesia the twitch response of the adductor pollicis muscle was recorded after supramaximal stimulation of the ulnar nerve at the wrist. Prior to tracheal intubation a bolus dose of vecuronium was given (0.08 mg/kg body weight). During surgery supplementary doses of 0.02 mg/kg body weight were given at a train-of-four (TOF) ratio of 0.25. The duration of effect (DUR-IT-25) and recovery time from a TOF ratio of 0.10 to 0.25 (Recovery-IT-10-25) were recorded. When comparing 10 iteration doses, the mean DUR-IT-25 in the 15 patients studied showed only minor variations (n.s.). Each patient had a near constant interval between the iteration doses; however, a noteworthy variation between individuals was found. Recovery-IT-10-25 was 250 +/- 80 (mean +/- s.d.) 240 +/- 80 and 260 +/- 80 s comparing the second, sixth and tenth iteration doses, respectively. In conclusion, the duration of effect varied considerably between patients. Each patient showed, however, a near constant iteration interval and a recovery time with only small variations. This indicates that cumulation is unlikely to exist following repetitive administration of vecuronium of 0.02 mg/kg body weight.

Adolescent↗
PubMed1988

Skeletal muscle function in primary fibromyalgia. Effect of regional sympathetic blockade with guanethidine.

Muscle fatigue is the most disabling symptom in primary fibromyalgia (PF), which in addition is characterized by generalised pain and muscle stiffness. In order to assess whether the fatigue is of central and/or peripheral origin, skeletal muscle function was studied by measuring maximum voluntary hand grip strength, and by measuring various contraction characteristics in the adductor pollicis muscle after electrical stimulation of the ulnar nerve. The PF-patients were also studied after a regional sympathetic blockade of the forearm with guanethidine. A lower hand grip strength was found in the PF-patients compared to the controls, before as well as during the sympathetic blockade. The developed force, measured during electrical stimulation, did not differ between patients and controls. A lower muscle relaxation rate was found in the PF-patients. The relaxation rate increased in the PF-patients during the sympathetic blockade. The results indicate both a central and a peripheral cause of muscle dysfunction. Activity in the muscle sympathetic system may be one link in the chain of events that leads to muscular symptoms in PF.

Action Potentials↗
PubMed1988

Skeletal muscle contraction characteristics in vivo in malignant hyperthermia susceptible subjects.

Ten malignant hyperthermia susceptible (MHS) subjects were investigated, all of them positive in in vitro tests. As a control group 12 healthy subjects were investigated. The investigation was done in a blind fashion during strictly standardized conditions. Electromechanical delay of contraction and half contraction time to tetanus were faster (P less than 0.05) while half relaxation time was shorter in the MHS subjects (P less than 0.05). Skin and intramuscular temperature were significantly higher in the MHS subjects (P less than 0.05). This indicates that MHS subjects differ in various skeletal muscle characteristics during "normal" conditions. Further studies to define the temperature level at which the test of muscle function is most discriminating are needed before it can be used for diagnostic purposes.

Adolescent↗
PubMed1987

Abnormal relaxation rates in subjects susceptible to malignant hyperthermia.

The acute malignant hyperthermia crisis appears to be mediated by a sudden and sustained rise in the concentration of sarcoplasmic calcium, leading to a prolonged muscle contraction. It is not known whether calcium metabolism in skeletal muscle is abnormal in malignant hyperthermia susceptible (MHS) subjects under normal conditions. A hypermetabolic state in skeletal muscle can be assessed in vivo by measuring relaxation rate. In the present study the relaxation rate was measured in the adductor pollicis muscle after electrical stimulation of the ulnar nerve. Ten MHS subjects with no clinical symptoms of muscle disease were investigated. Relaxation rates were found to be significantly higher in the MH-susceptible subjects compared with controls even under normal conditions (p less than 0.001). Determination of relaxation rate could thus be considered a possible addition to those methods currently available for the diagnosis of MHS.

Adolescent↗