Renal effects of hypotensive anaesthesia in combination with acute normovolaemic haemodilution with hydroxyethyl starch 130/0.4 or isotonic saline.

BACKGROUND: Hypotensive anaesthesia (HA) and acute normovolaemic haemodilution (ANH) are used separately to decrease per-operative blood loss. Reducing blood viscosity by adding ANH to HA may appear profitable in a situation with lowered perfusion pressure and concern about organ ischemia. The aim of this study was to clarify the influence of HA in combination with ANH using crystalloid or colloid as replacement fluid on renal function. METHODS: Hypotensive anaesthesia was induced in 11 patients referred to major spine surgery using sevoflurane in combination with fentanyl/remifentanil. Acute normovolaemic haemodilution was carried out by drawing venous blood into standard blood bags and replacing it by isotonic saline 0.9% (Group S) or HES 130/0.4 (Group V). Renal function was evaluated before, during and up to 8 h after hypotension as the glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) by means of 51Cr-EDTA and 125I-Hippuran clearances. RESULTS: Lowering mean arterial blood pressure decreased GFR and ERPF in both groups. During hypotension ERPF was lower in Group S (n = 5) than Group V (n = 6). Renal function was normalized postoperatively. We found a positive but non-significant correlation between the relative GFR change and the duration of hypotension. CONCLUSION: In conclusion, our study demonstrated that renal function, assessed by GFR and ERPF, is transiently reduced during the combination of hypotensive anaesthesia and acute normovolaemic haemodilution. A colloid-based fluid regime (HES 130/0.4) used for haemodilution may preserve renal function to a greater extent than a crystalloid-based regime (0.9% saline).

Thrombelastographic whole blood clot formation after ex vivo addition of plasma substitutes: improvements of the induced coagulopathy with fibrinogen concentrate.

BACKGROUND: Plasma substitutes such as hydroxyethyl starch (HES) and various dextrans may compromise the haemostatic system, thereby causing potentially dangerous bleeding. Whilst several mechanisms have been advanced to explain the nature of the coagulopathy induced by this colloid, there has been comparably little interest in devising ways to optimize haemostasis after a relative colloid overdose. METHODS: Real-time whole blood (WB) clot formation profiles were recorded using a thrombelastographic method employing activation with tissue factor. The coagulation tracings were transformed into dynamic velocity profiles of WB clot formation. WB from healthy individuals (n=20) was exposed to haemodilution of approximately 55% with isotonic saline, HES 200/0.5, HES 130/0.4, and dextran 70, respectively. Possible modalities for improvement of the induced coagulopathy were explored, in particular ex vivo addition of a fibrinogen concentrate. RESULTS: WB coagulation profiles changed significantly with decreased clot strength, and a compromised propagation phase of clot formation. The duration of the initiation phase of WB coagulation was unchanged. No statistical differences were detected amongst the HES solutions and dextran 70. However, dextran 70 returned a more suppressed clot development and strength compared with the HES solutions. Ex vivo haemostatic addition of washed platelets (75 x 10(9) litre(-1)) and factor VIII (0.6 IU ml(-1)) produced insignificant changes in clot initiation, propagation, and in the clot strength. In contrast, ex vivo addition of a fibrinogen concentrate (1 g litre(-1)) improved the coagulopathy induced by all of the three individual plasma expanders tested. CONCLUSION: Coagulopathy induced by haemodilution with either HES 200/0.5, HES 130/0.4, and dextran 70 may be improved by fibrinogen supplementation.

The value of continuous blockade of the lumbar plexus as an adjunct to acetylsalicyclic acid for pain relief after surgery for femoral neck fractures.

In a randomized, double-blind investigation the analgesic effect of continuous blockade of the lumbar plexus as an adjunct to acetylsalicyclic acid by suppository after surgery for femoral neck fractures under spinal anaesthesia was examined in 20 patients. Before surgery, a catheter was inserted into the femoral nerve sheath. The patients were allocated randomly to receive bupivacaine or saline by bolus and then continuous infusion, started immediately after the operation. No statistically significant differences in additional morphine requirements, visual analogue pain scores or adverse effects were observed between the two treatment groups. It is concluded that continuous blockade of the lumbar plexus as an adjunct to rectal acetylsalicyclic acid offers no major additional pain relief after surgery for femoral neck fractures under spinal anaesthesia.

Healthcare workers' risk of contact with body fluids in a hospital: the effect of complying with the universal precautions policy.

OBJECTIVE: To test whether healthcare workers' knowledge of and compliance with the basic principle of the Universal Precautions policy (i.e., that all patients should be treated equally regarding contact with body fluids) influenced the rate of contact with patient blood. DESIGN: Survey based on anonymous questionnaires. SETTING: A 380-bed secondary and tertiary care hospital receiving emergency and elective patients. PARTICIPANTS: All employees having any contact with patients. Nine hundred one of 1,308 (69%) of the questionnaires were returned. RESULTS: Twelve percent of the respondents (95% confidence interval [CI95] = 10.0%-14.4%) had experienced any contact with patient blood in the week preceding their answer. Physicians had the highest rate of contact with blood followed by nurses. In the five groups--physicians, nurses, laboratory technicians and phlebotomists, nursing aides, and student nurses--contact with blood was less frequent in the subgroup that did know and comply with the basic principle of the Universal Precautions policy, compared with the subgroup that did not. When adding the results for the 5 groups, contact with blood was experienced by 91 of 571 (15.9%, CI95 = 13%-19%) of the personnel who did not know and comply with Universal Precautions. The personnel who did know and comply with Universal Precautions had a significantly lower (9 of 111 [8.1%], p < .05, CI95 = 3.8%-15%) rate of contact with blood. CONCLUSIONS: The healthcare workers who knew and complied with Universal Precautions had a significant lower rate of contact with patient blood than those who did not.

Increased urinary loss of uric acid in adults with acute respiratory failure requiring mechanical ventilation.

INTRODUCTION: The purpose of this study was to test a hypothesis of increased urinary excretion of uric acid as an indicator of adenosine triphosphate (ATP) degradation in adult patients with acute respiratory failure, and to look for a correlation to the clinical outcome. STUDY DESIGN: Prospectively 31 patients with acute respiratory failure were studied. The patients were divided into two groups according to the clinical outcome: the need for solely supplemental oxygen (group 1), death or mechanical ventilation (group 2). METHODS: Uric acid was determined by spectrophotometry. RESULTS: Mean uric acid excretion was 39 mumol/kg (range, 7 to 92 mumol/kg) body weight/per 24 h in group 1 (16 patients) compared with 65 mumol/kg/24 h (range, 8 to 253 mumol/kg/24 h) in group 2 (13 patients were mechanically ventilated, and two patients died). The difference was highly significant (p less than 0.0001). CONCLUSION: Increased amount of urinary uric acid was related to the severity of acute respiratory failure in adults.

[Continuous positive airway pressure (CPAP)--does the equipment live up to its name?]. / Continuous positive airway pressure (CPAP)--lever apparaturet op til navnet?

The purpose of this study was to evaluate the in- and expiratory pressures achieved by the use of different continuous positive airway pressure (CPAP) delivery systems. The study was performed on ten healthy adults breathing spontaneously with: 1) "simple CPAP", consisting of a fresh gas flow around 40 l/min and reservoir balloons of 2, 6 and 10 l and expiration against a water column, 2) a high-flow system CR60 CPAP, designed for home treatment and 3) another high-flow system Down's CPAP. Both high-flow systems used a venturi device (Downs Flow Generator, Vital Signs) giving flows around 90 and 170 l/min in our set-up, and the same PEEP valves (Vital signs) were used. All systems were tested with expiratory pressures set at 5, 10 and 20 cm H2O. Individual responses were found, but in general the simple CPAP with a 10 l latex balloon reservoir gave optimal CPAP. The high-flow systems were not found to provide better CPAP, however, CR60 CPAP was found also to be optimal with 5 and 10 cm H2O. Down's CPAP provided 3-5 cm higher expiratory pressure than the intended CPAP level. We recommend measurement of the pressure during the CPAP treatment to ensure that the intended CPAP is achieved.

[Continuous spinal analgesia. A review]. / Kontinuerlig spinal analgesi. En oversigt.

Continuous spinal analgesia is a recognized method of analgesia for surgical interventions which was originally described in 1907. A brief historical review is presented with a description of the current technique. Emphasis is laid on comparison with other regional techniques, particularly single-shot analgesia and epidural analgesia. A review is presented of the current knowledge about technique, particularly the equipment, analgesic agents, advantages and disadvantages and indications and contraindications. it is concluded that continuous spinal analgesia probably offers certain advantages, particularly cardiovascular stability. However, the lack of randomized comparisons of the various techniques make further clinically controlled investigations necessary to illustrate this.

Variation in spinal analgesia with plain bupivacaine 0.5% when repeated in the same patient.

The study was done to see if it was possible to predict the level of analgesia in repeated spinal blocks with our routine technique where the patient is seated during injection of plain 0.5% bupivacaine 3.5 ml at the L3-L4 interspace and placed in the lithotomy position after 0.5 min. Thirty patients with tumour of the bladder had two spinal blocks during a 13-month period. The segmental spread of sensory loss was tested with the pin-prick technique. A wide range of height of blocks was found, increasing with age. Regression analysis on maximum cephalad spread of the second spinal analgesia against the first had a slope of 0.48 (P less than 0.01 for the hypothesis that the slope is zero). A significant correlation between the time for maximal cephalad spread was found, while the correlation between duration of thoracal analgesia was non-significant.

Hypoalgesia following intrathecal morphine: a segmental dependent effect.

The onset phase of hypoalgesia, following intrathecal morphine, was assessed by experimental argon laser-induced pain. A dose of 0.4 mg morphine was injected pre-operatively at the L3-L4 level into nine patients. The thresholds to laser-induced pain and pain-evoked brain potentials were monitored for 2 h at the S1, L1, and C7 dermatomes. Hypoalgesia was detected at the S1 and L1 dermatomes after 5 and 15 min, respectively. No hypoalgesic effect was found at C7. This indicates that hypoalgesia was caused predominantly by segmental spinal mechanisms during the onset phase, and not by a general widespread effect. No latency changes (conduction delay) of the brain potentials evoked from the hypoalgesic dermatomes were found. Cutaneous pain, induced experimentally by laser stimulation, has the advantage of being quantitative and is useful to assess the onset and the segmental spread of hypoalgesia.

Subhypnotic doses of thiopentone and propofol cause analgesia to experimentally induced acute pain.

Subhypnotic doses of thiopentone are considered to have a hyperalgesic effect, while propofol has a hypoalgesic effect. We investigated the effect of these drugs on the nociceptive system by measuring the pain threshold to laser stimulation and the pain evoked potential (power and latency). Nineteen patients (ASA group I) participated. Twelve patients received thiopentone 0.5 mg kg-1 and propofol 0.25 mg kg-1 in random order separated by an interval of 14 h, and seven patients received saline. Immediately after the injection of both agents, the pain threshold was increased significantly (P less than 0.001) and the amplitude of the evoked potential was reduced significantly (P less than 0.05), while the latency of the evoked potential remained constant. It is concluded that, in subhypnotic doses, both thiopentone and propofol decrease the acute pain evoked by argon laser stimulation.

Postoperative pain treatment after open knee surgery: continuous lumbar plexus block with bupivacaine versus epidural morphine.

The anesthetic and side effects of a continuous lumbar plexus block ("3-in-1" block) were compared with that of epidurally administered morphine after open knee surgery. Twenty-two patients were randomized into two groups in this prospective, double-blind study. At the end of surgery, catheters were inserted for all the patients into both the femoral nerve sheath and the epidural space. Pain treatment was given as either bupivacaine in the femoral catheter or morphine in the epidural catheter, with saline in the other catheter. All treatments were given as a bolus dose followed by continuous infusion. If the patients had pain, they were given morphine intramuscularly on demand. The pain scores and supplemental morphine consumption were low in both groups and did not differ significantly. Lumbar plexus block produced a statistically significant a lower incidence of nausea, vomiting, pruritus and urinary retention. Although no significant differences in pain relief were shown between the two methods, we conclude that postoperative lumbar plexus block is preferable for postoperative pain relief because there is a lower frequency of side effects.

[The quality of a manual method for the identification of the lumbar vertebrae]. / Undersøgelse af kvaliteten af en manuel metode til bestemmelse af lumbalhvirvler.

In order to identify the spinous processes in the lumbar region, we employ the following rule: that "the line between the iliac crests passes through the spinous process of L4 or the intervertebral space between the 4th and 5th lumbar vertebrae". Three anaesthetists (two junior staff and one consultant) identified a spinous process marked by lead-shot in 33 patients prior to radiological examination. No significant differences were found between the estimates made by the junior staff and the consultant and none of the following factors were of significance for the estimates: height, weight, weight index, sex or age of the patients. When the patients were subdivided according to the radiographic degree of pathological findings in the lumbar spine, only 48% of the estimates were found to be correct while where no or slight changes were present, 71% of the estimates were correct. The differences were significant. It is concluded that 40% of the estimates were incorrect but never by more than one segment. The method may be employed where unreliability of one segment is acceptable.

Onset phase of spinal bupivacaine analgesia assessed quantitatively by laser stimulation.

Analgesia was assessed quantitatively at various dermatomes (C7, T8, T10, T12, L1, L3, S1) for the first 30 min after subarachnoid administration of 0.5% bupivacaine 3.5 ml. Stimulation with 10 needles and laser stimulation could evoke pain in dermatomes with adequate analgesia to single needle stimulation. Analgesia was assessed by thresholds (sensory and pain) and by pain-related brain potentials (amplitude and latency) to laser stimulation. Little analgesia was found at T10, but it increased gradually towards caudal segments. The dermatome related to the site of the injection (L3) was not blocked to a greater extent than the surrounding dermatomes. Conduction time (the latency of the evoked brain potential) was increased relatively more from the S1 dermatome compared with L1.

Continuous blockade of the lumbar plexus after knee surgery: a comparison of the plasma concentrations and analgesic effect of bupivacaine 0.250% and 0.125%.

In 20 patients a continuous block of the lumbar plexus was administered after knee-joint surgery, and the analgesic effect of two different concentrations of bupivacaine was compared. The same volume of bupivacaine was given to both groups of patients: a bolus dose of 0.4 ml/kg, 0.5% or 0.25%, followed by infusion of 0.14 ml/kg/h, 0.25% or 0.125%, respectively, via a catheter placed in the neurovascular fascial sheath of the femoral nerve according to the "3-in-1 block" technique. The median morphine consumption during the first 16 h postoperatively was 6.0 mg when bupivacaine 0.5/0.25% was used and 9.5 mg when 0.25/0.125% was used. This difference is not significant. The visual analogue pain scores were also similar in the two groups (P greater than 0.05). All plasma concentrations were below 4 micrograms/ml, the highest concentration measured being 3.6 micrograms/ml. It is concluded that when used for a continuous block of the lumbar plexus after knee-joint surgery, bupivacaine in a concentration of 0.125% offers the same pain relief as a concentration of 0.25%, and the risk of toxic reactions is reduced.

[Inguinal paravascular block (3-in-1 block)]. / Den ingvinale paravaskulaere blokade ("3-i-1" blok).

The three main nerves from the lumbar plexus may be blocked by injection of local anesthetic into the facial envelope of the femoral nerve ("three-in-one block"). The femoral nerve may be localized by obtaining paresthesia, by employing a nerve stimulator or by the loss of resistance technique. We prefer the use of a nerve stimulator. The "three-in-one block" may be employed for immediately pain relief of pain and for treatment of postoperative pain from fractures in the hip, femur and knee. Introduction of a catheter into the femoral nerve sheath is recommended to provide continuous block of the lumbar plexus for relief of postoperative pain.

Spinal anaesthesia in young patients using a 29-gauge needle: technical considerations and an evaluation of postoperative complaints compared with general anaesthesia.

One hundred patients aged 18-49 yr, undergoing elective arthroscopy of the knee joint, were allocated randomly to either spinal anaesthesia using a 29-gauge spinal needle or general anaesthesia. Dural puncture was considered difficult in 18% of the patients receiving spinal anaesthesia. In three patients (6%) it was necessary to supplement the spinal anaesthetic with general anaesthesia. Spinal and general anaesthesia were otherwise uneventful in all patients. The incidence of postoperative headache was similar in the two groups. One patient developed post dural puncture headache following spinal anaesthesia. This headache was of short duration and disappeared without treatment. Spinal anaesthesia caused more backache than general anaesthesia, otherwise the frequency of postoperative complaints was the same or lower. Ninety-six percent of the patients receiving spinal anaesthesia would prefer the same anaesthetic for a similar procedure in the future.

[Calculation of the amount of thiopental used in induction of anesthesia]. / Opgørelse af tiopentalforbruget ved anaestesi-indledning.

A retrospective investigation was undertaken of the amount of thiopental employed in induction of anaesthesia. This revealed that only three factors were of significance for the dosage employed: age, weight and cardiac disease. In patients over the age of 70 years, the dosage could be reduced by 30%. In patients of more than 10% overweight, the dosage could be reduced by 7% and in patients who were 10% underweight, the dosage was increased by 10%. In cases of heart disease the dosage was reduced by 20% in the proportion of 5 mg thiopental per kg body-weight.

[Transdermal scopolamine to prevent postoperative nausea and vomiting after uterine curettage and termination of pregnancy. A double-blind clinically controlled study with placebo]. / Transdermal skopolamin som profylakse mod postoperativ kvalme ved abrasio uteri og abortus provocatus. En dobbeltblind klinisk kontrolleret undersøgelse med placebo.

A randomized double-blind clinically controlled investigation with a placebo was undertaken to investigate the prophylactic effect of transdermal scopolamine on postoperative nausea and vomiting after dilatation and curettage and termination of pregnancy. No significant difference was found between the placebo and transdermal scopolamine. On the other hand, the patients in the scopolamine group had significantly more postoperative discomforts which were attributable to the anticholinergic effect of scopolamine. Transdermal scopolamine cannot be recommended for the prophylaxis of postoperative nausea and vomiting following uterine curettage and termination of pregnancy.

[CT study of brain atrophy--the value of various study methods]. / CT-Untersuchung von Hirnatrophie--Wert verschiedener Untersuchungsmethoden.

55 rather young patients suspected of dementia were examined via CT to assess the comparative value of various CT examination methods to determine cerebral atrophy. The patients were assessed clinically and classified as normal (24), slightly demented (21) and moderately demented (10). There were no severely demented patients. The parameters measured consisted of several diameters and indexes as well as the volume of the ventricular system and of the subarachnoidal space. The atrophy level was also determined visually. With the exception of the breadth of the third ventricle there was no correlation between internal cerebral atrophy and the level of dementia. Neither the mean breadths of four external sulci nor the volume of the subarachnoidal space (both being representative of external atrophy) showed any significant correlation with the degree of dementia of the patients on the levels 0.005 or 0.025, respectively. However, the results were not better than those obtained by visual assessment of external atrophy. Reasons are discussed why objective measurements do not yield reliable results.