Effect of Smoking on the Central Circulation at Rest and during Exercise as Studied by Radiocardiography

The pulmonary vessels are the first target of tobacco smoke in the circulatory system, but the functional changes occurring in the pulmonary circulation are poorly understood. Hence 46 volunteers were studied by radiocardiography under the following conditions: 1. At rest before and after smoking 2 cigarettes (15 men); 2. After repeated ergometer exercise (5 min, 100 W) with and without smoking (13 men); and 3. Control experiments under the corresponding conditions without smoking (18 subjects). A significant increase occurred in heart rate, cardiac output and systolic arterial blood pressure after smoking when at rest, but an almost significant decrease in pulmonary dispersion volume, whereas the heart rate and pulmonary capillary pressure attained significantly higher values after than before smoking in the exercise tests, with a significant decrease observed in stroke volume, pulmonary blood volume and pulmonary dispersion volume. It is concluded that smoking impairs physical performance, increases pulmonary capillary pressure and reduces pulmonary blood volume and probably the number of open capillaries.

Use of hecate-chorionic gonadotropin beta conjugate in therapy of lutenizing hormone receptor expressing gonadal somatic cell tumors

Improvement of cancer treatment is a major challenge of medical research. Despite the immense efforts made in the improvement of diagnosis and treatment, cancer remains a major concern and cause of morbidity and mortality. Most of the modern anti-neoplastic therapies have severe side effects, and tumor cells often develop drug resistance. There is promise in the new generation of treatments (gene therapy, immunotherapy, vaccines, etc.) that are under development, but the efficacies and side effects of such therapies have so far been disappointing. Receptor-based therapies are not new, but many normal cells also present the same receptors reducing the specificity of such approaches. Several lytic peptides have been investigated because of they appear to kill cancer cells due to changes of their membrane potential. Thus, linking receptor-specific ligands to lytic peptides is expected to augment the specificity of targeting and decrease the toxicity of lytic peptides on normal cells. One such polypeptide is hecate (an analogue to the bee venom main component, melittin) that preferentially kills cancer cells at low doses. When this peptide is fused with the 81-95 amino acid fragment of chorionic gonadotropin-beta (CGbeta) subunit (hecate-CGbeta), it targets cells expressing luteinizing hormone receptor (LHR), even at very low doses, or when LHR is expressed at low level. Our recent data showed that this peptide conjugate is efficient in destroying LHR-positive cells in xenografts and more importantly in transgenic mouse models developing LHR-positive somatic cell tumors in gonads. The mechanism of action of hecate-CGbeta after binding to LHR is destruction of cell membranes resulting in rapid cell death by necrosis with minimal side effects. This review summarizes our findings on the action of this novel peptide and considers the future potential of this family of targeting peptides in the treatment of neoplasias.

Factors associated with post-operative myocardial ischaemia in elderly patients undergoing major non-cardiac surgery

Forty patients (> 65 years) undergoing hip arthroplasty or peripheral vascular surgery both associated with high risk for post-operative myocardial ischaemia were randomized to receive either spinal or general anaesthesia. Ambulatory ECG recording (Holter) until the third post-operative morning, a daily 12-lead ECG and serum creatine kinase and troponine concentraItions were obtained. The number of ischaemic episodes, total duration of ischaemia and ischaemic minutes per hour were noted for each patient peri-operatively. Sixteen of the patients (40%) had post-operative myocardial ischaemia. An intra-operative increase in the plasma concentration of norepinephrine but not epinephrine was detected in the patients who later developed post-operative myocardial ischaemia. The increase in plasma norepinIephrine concentrations correlated with the decrease in core temperature. The type of anaesthesia had no effect on the incidence of myocardial ischaemia during or after surgery. Our results suggests that intra-operatively decreased core temperature and the increase in plasma concentration of norepinephrine probably caused peripheral vasoconstriction leading to latent cardiac dysfunction. These events should be avoided in the patients at risk of post-operative cardiac ischaemia.

Efficacy and side effects of tramadol versus oxycodone for patient-controlled analgesia after maxillofacial surgery

Tramadol, a weak opioid mu-receptor agonist, may have a favourable potency and side effect profile for intravenous patient-controlled analgesia (PCA). In a prospective, double-blind, randomized study involving 54 patients, tramadol was compared with oxycodone in PCA after maxillofacial surgery. All the patients were given diclofenac sodium 1 mg kg-1 intramuscularly and dexamethasone 8 mg twice a day. Post-operatively patients received tramadol or oxycodone by a PCA apparatus (lockout 5 min, tramadol 0.3 mg kg-1 bolus, oxycodone 0.03 mg kg-1 bolus). During the immediate recovery period, opioid was administered i.v. in a double-blind fashion, either tramadol 10 mg or oxycodone 1 mg increments until the pain control was judged to be satisfactory by the patient. Pain was assessed at rest and during activity (mouth opening) before and after loading, at 2 h after commencing the PCA, as well as at 21.00 and at 09.00 hours on the following morning. Side effects were recorded. The potency ratio of tramadol to oxycodone was found to be approximately 8:1. There was no significant difference between the groups in the VAS scores for pain. No respiratory depression was identified. Tramadol was found to provide adequate analgesia after maxillofacial surgery without risk of respiratory depression. However, the incidence of nausea was slightly greater in the tramadol group than in the oxycodone group (44% vs. 28%, NS).

Changes in heart rate variability in elderly patients undergoing major noncardiac surgery under spinal or general anesthesia

BACKGROUND AND OBJECTIVES

Heart rate variability (HRV), widely used as an indicator of activity of the autonomic nervous system, has been reported to decrease during and after both spinal and general anesthesia in patients without cardiovascular disease. We evaluated the changes in HRV bands in 40 patients with a high risk of ischemic heart disease.

METHODS

The patients were randomly assigned to receive either spinal (SA) or general anesthesia (GA) for elective total hip arthroplasty or peripheral vascular surgery. Anesthetic techniques and perioperative fluid administration were standardized. Holter monitoring was started preoperatively and continued until the third postoperative day. Three HRV frequency bands were analyzed.

RESULTS

A significant decrease was seen in very low frequency (VLF) and low frequency (LF) bands during GA but not during SA. Also the LF/high frequency (HF) ratio decreased during GA but not during SA. A decrease in all HRV frequency bands was seen after both types of anesthesia. None of the frequency bands returned back to the preoperative level during the 3-day trial. Postoperatively circadian variation was found only in the VLF band after SA.

CONCLUSIONS

The sympathovagal balance (LF/HF) is more stable during SA than during GA in patients with a high risk of ischemic heart disease. The postoperative decrease in HRV bands, however, is independent of the anesthetic technique.

Comparison of intrathecal morphine and continuous femoral 3-in-1 block for pain after major knee surgery under spinal anaesthesia

Major knee surgery is associated with moderate or severe post-operative pain. Intrathecal morphine and continuous femoral 3-in-1 block were compared prospectively in 40 patients for pain after major knee surgery under spinal anaesthesia, with 4 mL isobaric 0.5% bupivacaine. In a random order, 20 patients received preservative free morphine 0.3 mg mixed with spinal bupivacaine. In 20 patients, following spinal anaesthesia with only bupivacaine, femoral 3-in-1 block was performed post-operatively with 0.5% bupivacaine 2 mg kg-1. The block was continued via a catheter with 0.25% bupivacaine 0.1 mL h-1 kg-1 until the next morning (24 h after induction of spinal anaesthesia). Intramuscular oxycodone was given as a rescue analgesic in all patients. Two patients from the femoral group were excluded due to technical failure. Three patients in the morphine group and one patient in the femoral group did not need any additional oxycodone. In the morphine group on average 2.8 (range 0-7) and in the femoral group 3.2 (0-5) additional doses of oxycodone were needed during the 24 h observation period. The mean pain scores were significantly lower in the morphine group at 9 and 12 h into the 24-h trial. Itching was seen only in the morphine group (40% of the patients). Other side effects were similar in the two groups. All patients were satisfied with their pain therapy. Both intrathecal morphine and femoral 3-in-1 block alone were insufficient for the treatment of severe pain after major knee surgery.

Comparison of double-hole and single-hole pencil-point needles for spinal anesthesia with hyperbaric bupivacaine

BACKGROUND AND OBJECTIVES

The use of thin single-hole pencil-point (SHPP) spinal needles may be a reason for subarachnoid maldistribution of local anesthetic. A new double-hole pencil-point (DHPP) needle may be preferable because of a theoretic more uniform initial distribution of local anesthetic.

METHODS

This was a prospective, double-blinded study of 50 patients randomly selected to have spinal anesthesia using either single-hole 27-gauge (B. Braun, Melsungen, Germany) or double-hole 26-gauge (A.L.B. Medical Inc., U.S.A.) pencil-point needles. The former were inserted with the side port directed caudally and the latter with openings in both caudal and cranial direction. Two milliliters of hyperbaric 0.5% bupivacaine were injected in 1 minute, and sensory and motor block were studied at regular intervals during spinal anesthesia. All patients were interviewed on the first (personal) and the seventh (mailed questionnaire) postoperative day. Furthermore, microscopic inspection of the spinal needles was performed.

RESULTS

There were no statistically significant differences in sensory or motor block levels between the two needle types at any time during spinal anesthesia. Likewise, there was no difference in the duration of spinal block. The postanesthetic side effects (headache, backache, pricking, numbness, weakness) were similar in both groups. Light and electron microscopic examination showed resistance of the SHPP needles to tip damage. On the other hand, the DHPP needle tips seemed to be distorted quite frequently, and, even in unused needles, the tip was blunt and asymmetric.

CONCLUSION

There was no difference between the spread of analgesia using either SHPP or DHPP spinal needles. The DHPP needles appear to be vulnerable to tip damage from mechanical contact.

Satisfaction with dental care among elderly Finnish men

To study satisfaction with dental care among elderly Finnish men and to estimate the role of different factors affecting it, a questionnaire was sent to a systematic sample of 2043 elderly Finnish men (mean age 73 years). Acceptably filled-out questionnaires were returned by 1561, a participation rate of 76.4%. The questionnaire included 44 questions concerning dental and denture services and a modified 14-item Dental Satisfaction Questionnaire. The subjects were asked to express how strongly they agreed or disagreed with each of the 14 statements. These were later transformed and recoded to indicate level of satisfaction from +2 (very satisfied) to -2 (very dissatisfied). Overall satisfaction was estimated by summing up all the 14 scores. Dentate subjects were significantly (P<0.01) more satisfied than the edentulous. Subjects were least satisfied with dental care fees and most satisfied with accessibility and availability of services. Dentate subjects viewed almost all 14 items significantly more favorably than did the edentulous. Economics was seen to have a strong influence on dissatisfaction with dental care fees, which was related to income level. Maintaining the remaining dentition and supporting the dentition with fixed or removable dentures seem to be the means to increase satisfaction among the dentate. The benefits of belonging to a clinic's recall system should be explained thoroughly to the elderly.

Comparison of respiratory effects of tramadol and pethidine

Tramadol is a centrally acting opioid with a low affinity for mu-opioid receptors, which has been claimed not to depress respiration as do the classic opioids. The respiratory effects of intravenous (i.v.) pethidine (0.6 mg kg-1) and tramadol (0.6 mg kg-1) were compared in 36 ASA Grade I-II patients in a placebo-controlled double-blind study. After induction of anaesthesia with propofol followed by suxamethonium-facilitated endotracheal intubation, the patients spontaneously breathed halothane in 70% nitrous oxide and oxygen via a non-rebreathing valve. Inspiratory and expiratory oxygen, and end-tidal carbon dioxide concentrations (PETCO2), tidal volume (VT), minute volume of ventilation (MV) and respiratory rate were monitored by a side-stream spirometry at an end-tidal halothane of 0.3%. The recordings were collected before surgery. Pethidine caused significant respiratory depression seen as an increase in fractional inspiratory-expiratory oxygen difference and PETCO2 and as a decrease in MV and respiratory rate. However, the effects of tramadol were similar to those of a placebo. Tidal volume was not affected by any study drug. In conclusion, tramadol 0.6 mg kg-1 was shown not to be associated with respiratory depression, unlike equipotent dose of pethidine in this setting.

Comparison of intrathecal morphine and continuous femoral 3-in-1 block for pain after major knee surgery under spinal anaesthesia

Major knee surgery is associated with moderate or severe post-operative pain. Intrathecal morphine and continuous femoral 3-in-1 block were compared prospectively in 40 patients for pain after major knee surgery under spinal anaesthesia, with 4 mL isobaric 0.5% bupivacaine. In a random order, 20 patients received preservative free morphine 0.3 mg mixed with spinal bupivacaine. In 20 patients, following spinal anaesthesia with only bupivacaine, femoral 3-in-1 block was performed post-operatively with 0.5% bupivacaine 2 mg kg-1. The block was continued via a catheter with 0.25% bupivacaine 0.1 mL h-1 kg-1 until the next morning (24 h after induction of spinal anaesthesia). Intramuscular oxycodone was given as a rescue analgesic in all patients. Two patients from the femoral group were excluded due to technical failure. Three patients in the morphine group and one patient in the femoral group did not need any additional oxycodone. In the morphine group on average 2.8 (range 0-7) and in the femoral group 3.2 (0-5) additional doses of oxycodone were needed during the 24 h observation period. The mean pain scores were significantly lower in the morphine group at 9 and 12 h into the 24-h trial. Itching was seen only in the morphine group (40% of the patients). Other side effects were similar in the two groups. All patients were satisfied with their pain therapy. Both intrathecal morphine and femoral 3-in-1 block alone were insufficient for the treatment of severe pain after major knee surgery.

Home-readiness after spinal anaesthesia with small doses of hyperbaric 0.5% bupivacaine

Fifty-four patients were studied prospectively to evaluate home-readiness after a small dose (1 or 2 ml) of subarachnoid hyperbaric 0.5% bupivacaine. The block regressed significantly earlier in the 1 ml group than in the 2 ml group (p < 0.05). The patients were also able to walk significantly earlier in the 1 ml group (median 161 min and 231 min in the 1 ml and 2 ml groups, respectively) (p < 0.05). However, there were no significant differences between the groups in time of ability to void. We conclude that adequate surgical anaesthesia can be achieved with small doses of hyperbaric bupivacaine used for spinal anaesthesia. Although the sensory and motor block after 1 or 2 ml hyperbaric bupivacaine recovered within a reasonable time for day-case surgery, in some patients recovery of the ability to void was delayed to an undesirable extent.

Comparison of respiratory effects of tramadol and oxycodone

STUDY OBJECTIVE

To compare the respiratory effects of tramadol and oxycodone.

DESIGN

Placebo-controlled, double-blind randomized study.

SETTING

IV Department of Surgery, Helsinki University Central Hospital.

PATIENTS

36 ASA physical status I and II patients undergoing minor surgery with general anesthesia.

INTERVENTIONS

The respiratory effects of intravenous (i.v.) tramadol 0.6 mg/kg and oxycodone 0.04 mg/kg were compared after induction of anesthesia with propofol and succinylcholine-facilitated endotracheal intubation. Patients spontaneously breathed halothane in 70% nitrous oxide and oxygen via a nonrebreathing valve. The trial drugs or placebo were given after recovery from neuromuscular block.

MEASUREMENTS AND MAIN RESULTS

Inspiratory and expiratory oxygen and end-tidal carbon dioxide concentrations (ETCO2), tidal volume (VT) minute volume of ventilation (VE), and respiratory rate (RR) were recorded by side-stream spirometry with end-tidal halothane of 0.3% for 30 minutes before surgery. Oxycodone caused a significant respiratory depression seen as an increase in the inspiratory-expiratory oxygen difference and ETCO2 and as a decrease in VE and RR. On the contrary, the effect of tramadol were similar to those of placebo. VT was not affected by any study drug.

CONCLUSION

Tramadol was not associated with respiratory depression in the present setting.

Intravenous ketorolac vs diclofenac for analgesia after maxillofacial surgery

PURPOSE

To compare the efficacy of the non-steroidal antiinflammatory drugs (NSAID), ketorolac and diclofenac in prevention of pain after maxillofacial surgery.

METHODS

Sixty ASA I-II patients (30 in each group) received randomly, and double blindly either ketorolac 0.4 mg.kg-1 or diclofenac 1.0 mg.kg-1 iv after general anaesthesia induction, before surgical incision. In the ketorolac group, the same dose was repeated iv three times at six hour intervals. The diclofenac group patients received diclofenac 1.0 mg.kg-1 after 12 hr iv. Rescue analgesic medication consisting of oxycodone 0.03 mg.kg-1 iv, was administered by a patient controlled analgesia apparatus.

RESULTS

Two patients in the ketorolac and three patients in the diclofenac group did not need oxycodone during the study period. On average, 12 and 11 doses of oxycodone were needed in the ketorolac and the diclofenac groups, respectively (NS). Side-effects were similar in both groups. All patients except one were satisfied with the pain therapy.

CONCLUSION

Parenteral ketorolac (0.4 mg.kg-1 four times in 24 hr) and diclofenac (1 mg.kg-1 twice in 24 hr) were similar, but insufficient alone, for analgesia after maxillofacial surgery.

Growth and type-II collagen expression in the glenoid fossa of the temporomandibular joint during altered loading: a study in the rat

The aim of this study was to measure changes in growth of the glenoid fossa and its articular eminence after decreased loading. A further aim was to evaluate the role of mechanical forces in relation to the existence of a cartilage layer, by determining type-II collagen secretion. A total of 99 Wistar rats were used: 48 animals were fed whole pellets and 51 were fed ground pellets. At age 21 days, after weaning, the upper and lower incisors of the soft-diet group were shortened by cutting them, twice a week. Ten animals fed whole pellets and 10 fed ground pellets were injected i. p. with Alizarin red (200 mg/kg) at ages 22, 30 and 40 days, and killed at ages 30, 40 and 50 days respectively. The heads were freed from the soft tissue and the zygomatic process cut sagittally at the deepest point of the greatest transversal concavity of the eminence. Bone apposition was measured. The other animals were used for studies involving collagen II immunostaining. Bone growth decreased in the group fed ground pellets except in the anterior-most part of the glenoid fossa at 50 days. Immunohistochemical analysis revealed larger areas of anti-collagen II staining in the group fed whole pellets, most markedly in the posterior part of the glenoid fossa. Growth of the articulationg surface of the temporal component of the temporomandibular joint appears to depend on mechanical factors, such as the condyle. The underlying mechanics seem likely to be different. The presence of type-II collagen is obviously not regulated only by compressive forces but probably also by tension loading.

Effect of reduced articular function on deposition of type I and type II collagens in the mandibular condylar cartilage of the rat

A group of rats was fed a soft diet after weaning and the incisors shortened regularly to keep them out of occlusion. The controls were fed a hard diet. Immunohistochemical techniques and image analysis were employed to investigate deposition of pro-type I collagen and type II collagen, and the thickness of articular cartilage layers in the mandibular condyle. The immunostaining against pro-type I collagen was most intense intracellularly in the fibrous and upper chondroblast layers in 30- and 50-day-old rats fed a hard diet. In the rats fed a soft diet, marked intra- and extracellular staining against pro-type I collagen was visible in the upper chondroblast and upper hypertrophic layers but also in the lower hypertrophic layer. The intensity of staining against type II collagen was weak in animals on a soft diet, while in the animals fed a hard diet the staining was intense in the superior layers of mature chondroblasts. The total number of chondroblasts recorded was reduced by 35 percent at the age of 50 days in the soft-diet compared to the hard-diet animals. The results show that the deposition of type I and II collagens, the thickness of the cartilage cell layers and the number of chondrocytes are sensitive to alterations in loading.

Transient radicular irritation after bupivacaine spinal anesthesia

BACKGROUND AND OBJECTIVES

Transient radicular irritation (TRI) has been described to occur following spinal anesthesia with hyperbaric 5% lidocaine. The authors recently used only isobaric or hyperbaric 0.5% bupivacaine for spinal anesthesia. All patients who had spinal anesthesia for various kinds of surgery were interviewed after the operation to discover the possibility of TRI following bupivacaine spinal anesthesia.

METHODS

The study included 226 patients. Isobaric 0.5% bupivacaine was given to 116 patients and hyperbaric 0.5% bupivacaine to 110. The local anesthetic was chosen according to the expected duration of surgery. All patients were interviewed by an anesthesiologist 24 hours after spinal anesthesia, and after 1 week the patients were asked to return a written questionnaire. If pain not associated with operation was noted, the patients were interviewed by phone.

RESULTS

One 48-year-old woman reported TRI after spinal anesthesia (saddle block) with hyperbaric 0.5% bupivacaine in the 24-hour interview. Her spinal anesthetic was performed in a sitting position and the anal surgery in a lithotomy position. In the 1-week questionnaire (response rate 92%), none of the other patients fulfilled our criteria for TRI.

CONCLUSIONS

In spite of one case of TRI, the authors consider bupivacaine to be safe for spinal anesthesia. The association of the sitting and lithotomy positions to the restricted distribution of hyperbaric solution and consequent TRI warrants further studies.

Premedication with promethazine and transdermal scopolamine reduces the incidence of nausea and vomiting after intrathecal morphine

Intrathecal morphine provides effective postoperative pain relief in major orthopaedic surgery. In use, however, is associated with unpleasant side effects like nausea and vomiting. The effect of different premedications on postoperative emetic sequelae induced by intrathecal morphine was studied in a prospective, double blind study. Sixty patients scheduled for arthroplasty surgery of the lower extremity were anaesthetized with spinal anaesthesia with a combination of isobaric bupivacaine 20 mg and morphine 0.3 mg. For premedication the patients were randomised to three groups of equal size. They received either oral diazepam (5-15 mg), oral promethazine (10 mg) or a combination of promethazine and transdermal scopolamine (1.5 mg). Sixty percent of the patients with both promethazine and transdermal scopolamine were totally free from postoperative nausea and vomiting (PONV) symptoms compared to those premedicated with diazepam (40%) or promethazine alone (30%). Promethazine together with transdermal scopolamine reduced significantly the number of patients with vomiting (to 25%) and also vomiting episodes. This combination was also more efficient in reducing the incidence of nausea (to 25%) and nausea episodes than promethazine along (P < 0.05). Combination also reduced the requests for additional pain relief (P < 0.05). PONV occurred in a majority of patients during the first 12 hours of the 24 hour study period and the need for additional analgesics thereafter. The incidence of itching (50-65%) and urinary catheterisation (55-70%) was similar in all groups. In conclusion, the combination of oral promethazine and transdermal scopolamine was most effective in reducing PONV symptoms and also reduced the need for postoperative pain treatment.

Anaphylactoid skin reactions after intravenous regional anaesthesia using 0.5% prilocaine with or without preservative--a double-blind study

Methylparaben, the preservative of various local anaesthetic solutions, is a potential allergen. In a double-blind study, 0.5% prilocaine with (Citanest, n = 100) or without (n = 100) methylparaben were compared for the occurrence of skin reactions after intravenous regional anaesthesia of the arm in surgical patients. Skin reactions were registered after the deflation of the tourniquet cuff, and intradermal tests were performed with 0.5% prilocaine, 0.1% methylparaben and saline in all patients. Seventeen patients in the Citanest group and four patients in the methylparaben-free prilocaine group developed erythematous skin reactions in the exposed arm after deflation of the tourniquet cuff (P < 0.05, between the groups). The skin symptoms disappeared within an hour and were always restricted to the region which had been anaesthetised. None of the affected patients had positive intradermal tests. The observed skin reactions are probably non-IgE-mediated anaphylactoid reactions in which the presence of methylparaben in the local anaesthetic solution plays a major role.

Effect of unilateral masticatory function on craniofacial growth in the rabbit

In this study the main purpose was to investigate the effect of altered masticatory function on the shape and inclination of the articular surface of the glenoid fossa, and on the growth of the mandible in the rabbit. The maxillary and mandibular molars of 14, 10-d-old rabbits were ground down to the gingiva on the right side twice a week; 9 were controls. At age 50 d all rabbits were killed, soft tissue of the heads was removed, and the measurements were made. The inclination of the articular surface of the glenoid fossa was shallower on both sides in the experimental group than in the controls; the difference was greater on the right side. There were dimensional and angular differences between right and left sides of the mandible and maxilla in the experimental animals. In conclusion, unilateral masticatory function was found to cause an asymmetric craniofacial growth. Furthermore, function has an effect on the shape of the glenoid fossa, especially on the balancing side, in conjunction with asymmetric function.

Transient radicular irritation after spinal anaesthesia with hyperbaric 5% lignocaine

We have studied prospectively 600 patients who had spinal anaesthesia for minor surgery, to evaluate the incidence of transient radicular irritation after the block. The anaesthetic agent (hyperbaric 5% lignocaine, hyperbaric 0.5% bupivacaine or plain 0.5% bupivacaine) was chosen according to the anticipated duration of surgery. We obtained information after operation from 537 patients (282 by telephone, 255 by letter). Ten percent of patients anaesthetized with hyperbaric 5% lignocaine (27 patients) had transient bilateral radiating pain in the lower extremities, buttocks, or both. Typically the pain started within 24 h after spinal anaesthesia, lasted less than 2 days and was described as mild. Lignocaine was the only variable that correlated with this pain. Two patients complained of symptoms after hyperbaric 0.5% bupivacaine but these were atypical compared with pain after lignocaine. None of the patients anaesthetized with plain bupivacaine had similar complaints. We conclude that the use of 5% hyperbaric lignocaine for spinal anaesthesia should be reconsidered.

Comparison of parenteral diclofenac and ketoprofen for postoperative pain relief after maxillofacial surgery

Non-steroidal anti-inflammatory drugs (NSAID) effectively reduce the need for opioid analgesia after various types of surgery. The efficacy of diclofenac and ketoprofen to relieve pain after maxillofacial surgery was compared in the present study. In a randomized and double-blind fashion, 90 ASA I-II patients (16-60 yrs) were studied, divided into three groups: Thirty patients received 1.0 mg.kg-1 diclofenac i.v. after general anaesthesia induction, before surgical incision, and four hours later the same dose was given i.m. Thirty patients received ketoprofen 1.35 mg.kg-1 i.v. and i.m., as above, and a third group of 30 patients received a comparable volume of saline i.v. and i.m. The patients received supplemental analgesia using a patient controlled analgesia apparatus; the rescue medication consisted of 0.03 mg.kg-1 oxycodone i.v. (four-hour maximum dose was 0.4 mg.kg-1) during the 24-hour follow-up. The three groups were comparable regarding the type of maxillofacial surgery (osteotomies vs. soft tissue surgery). Overall, there was a lower need for i.v. oxycodone during the 24-hour period in the diclofenac group (269 doses) than in the ketoprofen group and in the saline group (388 doses, each) (P < 0.01). The significantly lower number of oxycodone administrations in the diclofenac group was a result of a distinguishable difference, particularly during the first four hours after surgery. There was no statistically significant difference in the incidence of side effects of the analgesic therapy between the three groups.

Auditory disturbance associated with interscalene brachial plexus block

We performed an audiometric study in 20 patients who underwent surgery of the shoulder region under an interscalene brachial plexus block (IBPB). Bupivacaine 0.75% with adrenaline was given followed by a 24-hr continuous infusion of 0.25% bupivacaine. Three audiometric threshold measurements (0.25-18 kHz) were made: the first before IBPB, the second 2-6 h after surgery and the third on the first day after operation. In four patients hearing impairment on the side of the block was demonstrated after operation, in three measurements on the day of surgery and in one on the following day. The frequencies at which the impairment occurred varied between patients; in one only low frequencies (0.25-0.5 kHz) were involved. The maximum change in threshold was 35 dB at 6 kHz measured at the end of the continuous infusion of bupivacaine. This patient had hearing threshold changes (15-20 dB) at 6-10 kHz on the opposite side also. IBPB may cause transient auditory dysfunction in the ipsilateral ear, possibly via an effect on sympathetic innervation.

Technical problems and side effects associated with continuous intrathecal or epidural post-operative analgesia in patients undergoing hip arthroplasty

Fifty-five patients undergoing hip arthroplasty under spinal anaesthesia (4 ml of 0.5% plain bupivacaine) were randomized to receive post-operative analgesia either using an intrathecal or an epidural catheter. Associated technical problems and side effects were studied. In both groups per-operative analgesia was achieved with intrathecal 0.5% plain bupivacaine, 4 ml. In the intrathecal infusion group a bolus dose of 100 micrograms morphine was injected through a spinal 28 gauge catheter followed by a 24 h infusion of 200 micrograms morphine (8.3 micrograms h-1). In the epidural infusion group a bolus dose of 2 mg of morphine was injected before the epidural 24 h infusion was started (morphine 200 micrograms h-1 + 0.25% bupivacaine 4 ml h-1). There were 10 catheter failures (two could not be inserted) in the intrathecal group and one in the epidural group. Three epidural catheter infusions failed due to other technical problems. The number of side effects was 21 in the remaining spinal group (n = 20) and 18 in the 20 epidural group patients with successful infusions. One patient in the spinal catheter group developed postdural puncture headache. For post-operative pain relief the patients in the epidural group needed less supplementary intramuscular oxycodone (five doses/four patients) than the spinal group (17 doses/nine patients) (P < 0.05).

Relative value of dental procedures

This study was conducted to develop a relative value method for dental procedures, and to evaluate the differences in values assigned by private and public sector dentists. Samples of 90 general practitioners and 120 clinical specialists were systematically drawn to represent all actively working Finnish dentists. The dentists were asked to assess the required time and know-how for performing various procedures compared to performing a two-surface amalgam filling (AF2). At the end, the dentists were asked to divide the value of 200 between time and know-how for the reference procedure (AF2). These figures were then utilized to calculate the average relative value for each procedure. Private practitioners' weighted relative values were 55.3% higher than the prices, and among public sector dentists they were 27.9% higher. Overall, know-how constituted more of the total value of the procedures than did time. Private practitioners' time assessments correlated well (r = 0.72-0.95) with the recommended prices. However, significant differences were often observed both in time and know-how assessments of individual procedures. Both time and know-how seem to be important factors when determining values for dental services. For evaluation of the value of output in the private sector, the use of prices is justified. However, when the productivity of non-profit dental offices is evaluated, a value system which is not based on market prices is needed.

Effects of sub-hypnotic doses of propofol on the side effects of intrathecal morphine

We have studied the effect of propofol on the side effects associated with intrathecal morphine in 40 patients undergoing major arthroplasty. Patients received spinal anaesthesia with plain 0.5% bupivacaine 20 mg mixed with preservative-free morphine 0.3 mg. Before injection of the local anaesthetic, the patients were allocated randomly to receive either a bolus dose of propofol 10 mg followed by an infusion of 30 mg/24 h or equal volumes of 10% Intralipid (control group). The number of patients without postoperative nausea and vomiting (PONV) was similar in both groups. However, the incidence of nausea and vomiting was lower in the propofol (13 and 22, respectively) than in the control (34 and 36) group (P < 0.01 and P < 0.05, respectively). Severe vomiting episodes were less frequent in the propofol group (1 vs 11; P < 0.05). Four patients in the propofol group and 12 patients in the control group had itching (P < 0.05). The incidence of urinary retention was similar in both groups. There was no additional sedation attributable to propofol. In conclusion, sub-hypnotic doses of propofol protected significantly against itching and had a modest effect on PONV after intrathecal morphine.

Effect of altered loading on condylar growth in the rat

The aim of this investigation was to ascertain whether lessening of function by feeding rats a soft diet and cutting their incisors can change the growth of the condyle. Sixty Wistar rats were divided into two groups; a control group fed whole pellets and a soft-diet group fed ground pellets. At the age of 21 days the upper and lower incisors of the soft-diet group were shortened by cutting with a wire cutter twice a week. Ten control rats and 10 soft-diet rats were injected with alizarin red (200 mg/kg) intraperitoneally at the age of 22, 30, or 40 days and killed at the age of 30, 40, or 50 days, respectively. The heads were freed of soft tissues, and the growth of the condylar process and the mandible was measured. The height growth of the condylar process was significantly greater in the soft-diet group by 30 and 40 days, and its length growth was greater in the soft-diet group by 50 days. It is concluded that the change in the amount of chewing force and the place of articulation of the condyle alters the growth of the condylar process. Lessening of the load increases condylar growth until a new balance is achieved.

Effect of mechanical forces on chondrocyte maturation and differentiation in the mandibular condyle of the rat

The effects of mechanical factors on the growth of the mandibular condyle were studied by monitoring the maturation of the mesenchymal cells in 55 rats. Thirty-five animals were fed normal pellet food, and 20 were fed a soft diet and their incisors were cut regularly. 3H-thymidine was injected intraperitoneally three days before death at 18, 23, or 33 days. Histologic sections showed the most advanced 3H-thymidine-labeled cells to occur deep in the cartilage, in the lower hypertrophic cell layer in anterior and posterior regions of the condyle, and in the upper hypertrophic cell layer in the superior region at the age of 18 days. A distinct difference in the maturation state of the labeled cells could also be observed between these regions. In animals fed a soft diet, maturation was slower in the superior region of the condyle and faster in the posterior region than in the normal rats. The rate at which cells stepped out of the proliferating cell pool was measured by use of monoclonal antibodies against proliferating cell nuclear antigen. The ratio between labeled cells in the proliferating cell layer and the number of labeled cells beneath it was greater in control animals than in the soft-diet animals. The rate of differentiation and maturation of mesenchymal cells into chondrocytes seems to be controlled by mechanical factors.

Intraarticular morphine for pain relief after knee arthroscopy performed under regional anaesthesia

Eighty patients scheduled to undergo knee arthroscopy were studied in random and double blind fashion. Spinal anaesthesia with hyperbaric 0.5% bupivacaine was selected for 40 overnight-in-patients. At the end of arthroscopy, 1 mg morphine or saline was injected intraarticularly. Local anaesthesia with 1% lidocaine plus adrenaline, was selected for another 40 out-patients. At the end of the arthroscopy either 1 mg morphine or saline was injected intraarticularly. As a rescue medication the spinal anaesthesia patients received oxycodone 0.14 mg kg-1 i.m. or ketoprofen 100 mg p.o. and the local anaesthesia patients received ketoprofen 100 mg p.o. The need for additional postoperative analgesic was almost similar in both spinal anaesthesia groups. The patients having local anaesthesia and given intraarticular morphine needed fewer doses of ketoprofen (22 doses) postoperatively than the control group (39 doses) (P < 0.05). Duration of analgesia was slightly longer after morphine than in the control group (ns). There was no difference between the morphine patients and the control patients in the two studies regarding the incidence of side effects. We conclude that postoperative analgesia in patients undergoing knee arthroscopy under local anaesthesia, but not under bupivacaine spinal anaesthesia, can be improved with a single intraarticular injection of 1 mg morphine.

Ocular complications in young adults with insulin-dependent diabetes mellitus since childhood

A cross-sectional study in 80 insulin-dependent diabetic patients born 1963-1968 who experienced the onset of diabetes before 15 years of age showed that at a mean age of 21.6 (range 17-25) years and after a mean duration of diabetes of 13.3 (range 6-24) years, 80% of the patients had retinopathy: 70% had background and 10% proliferative changes. Retinopathy correlated with the duration of the diabetes and poor glucose control at 15 years of age but not with the actual level of glycated haemoglobin. The severity of retinopathy was worse in women than in men. One patient (1.2%) was blind. Two patients had had cataract operations and 66% had myopic refraction in one or both eyes. In 61 patients a further period of ophthalmological follow-up of 3-4 years was included. After 20 years of diabetes, all had retinopathy and 29% had proliferative changes: 33% had received laser treatment after 8-27 (mean 16.1) years of diabetes. Altogether, 2 patients (2.5% of the original series) were blind. For prevention of diabetic retinopathy and blindness, good glucose control from puberty and careful ophthalmological follow-up after transfer of the patient from paediatric to adult diabetes care play major roles.

Articular disc and eminence modeling after experimental relocation of the glenoid fossa in growing rabbits

The articular surface of the glenoid fossa shows some analogy to the mandibular condyle, since the surface is covered by secondary cartilage, which makes the process more elastic than purely bony structures. The condylar cartilage has been shown to be responsive to alterations in load pressures, and this secondary type of cartilage is also able to increase its proliferative activity to a limited extent when the load pressure is altered. The aim here was to measure changes in proliferative activity and type II collagen secretion in the articular surface of the glenoid fossa after steady experimental posterior relocation of the fossa in the rabbit without actively interfering with normal masticatory action. The shape of the articular disc and interrelations of the joint components were measured macroscopically. Twenty-four five-day-old rabbits underwent gluing of the interparietal, temporoparietal, and lambdoidal sutures. Three experimental and 3 control rabbits were injected with tritiated thymidine at 10, 15, 20, and 30 days and were killed after 2 h for histological, autoradiographic, and immunohistochemical examination. The total number of labeled cells in the proliferative layer near the articular eminence was higher in the experimental group, the difference being greatest in the 15- and 20-day-old rabbits. Immunohistochemical examination revealed less staining for type II collagen on the postero-inferior side of the eminence in the experimental group. The articular disc was flattened in the experimental group, and the elastic tissue bundle connecting the articular eminence and the anterior border of the disc was significantly narrower and longer.

Glycosaminoglycan synthesis in the mandibular condyle during growth adaptation

Condylar growth was studied after an operation simulating functional orthodontic appliances. Twenty-five rabbits underwent a surgical operation for the induction of premature synostosis to displace the glenoid fossa posteriorly during growth. Twenty-five control rabbits underwent sham operations. At the age of 15 days, 10 experimental and 10 control animals and, at the age of 20 days, 5 experimental and 5 control animals were killed. Their mandibular condyles were organ-cultured for 3 h in the presence of radiolabelled sulphur. The condyles were used for autoradiographic purposes. Digital image analysis of autoradiograms of histological sections showed synthesis of glycosaminoglycans to have increased from the anterior to the posterior direction. This increase was more marked in experimental animals than in the condyles of control animals. Ten experimental and 10 control animals were killed at the age of 15 days, and mandibular condyles were organ-cultured for 1, 4 and 7 days. Differentiation of proliferating prechondroblasts into hypertrophied chondrocytes continued under organ culture conditions. A marked decrease in the proliferating cell layer was noticed, especially in control condyles. Hypertrophy was faster and came closer to the surface of the condyle in the anterior region of the condyle. This was most marked in the condyles of experimental animals. The results indicate that a procedure carried out on the glenoid fossa with the same effect as functional appliances increases the synthesis of extracellular matrix in the posterosuperior region of the mandibular condyle.

Effect of late posture change on the level of spinal anaesthesia with plain bupivacaine

We studied 40 patients, 18-60 yr, undergoing orthopaedic surgery of the lower limb under spinal anaesthesia. A midline lumbar puncture was performed in the L3-4 interspace using a 27-gauge needle with the patient in the lateral horizontal position. Plain bupivacaine 3 ml at room temperature was injected. The cephalad level of analgesia was assessed by pinprick 60 min after injection of local anaesthetic, at the end of surgery and again after the patient was moved into bed. All patients had a segmental level of the block of L1-T5 at the beginning of the study. The upper half of the patient's body was then tilted to a 30 degrees head-up position. Segmental spread was subsequently assessed by pinprick at 5-min intervals for 30 min. In six of the 40 patients (15%), increased cephalad spread of spinal analgesia occurred. The mean time from induction of spinal anaesthesia was shorter in these six patients (mean 92 min, range 80-115 min) than in the patients whose block did not change or was decreasing during the 30-min test (mean 119 min, range 83-210 min) (P < 0.05). We conclude that the patient should remain in the supine horizontal position until recovery from the spinal block.

Efficacy of epidural blood patch for postdural puncture headache

This prospective investigation was conducted to evaluate the efficacy of different volumes of epidural blood patch (EBP) for treatment of postdural puncture headache (PDPH) in 81 consecutive patients. In the first part of the investigation (Study part I), 10 ml of blood was injected for EBP in 28 patients. In the second randomized part of the investigation (Study part II), the patients were allocated to receive for EBP either 10 ml (27 patients) or 10-15 ml (26 patients), according to the height of the patient. The procedure was considered initially successful if PDPH disappeared completely during the 2-h recovery room follow-up. To evaluate the long-term success, a questionnaire was mailed to all patients. The EBP performed 3.7 +/- 2.9 days following the dural puncture was initially successful in 88-96% of the patients in the different study groups. In the questionnaire, only 50-68% of the patients reported that PDPH had disappeared immediately without recurrence. In 16-36% of the patients the PDPH returned at lesser intensity and in 14-17% PDPH was reported to have continued, disappearing gradually in all patients. Despite this, 87% of all patients were satisfied with the EBP treatment. There were no statistically significant differences between the groups. The results indicate that a larger, height-adjusted volume of blood for EBP in adults does not produce a better effect on PDPH compared to a standard 10-ml volume. Despite the excellent initial effect (91%) seen in our patients, a permanent effect of the blood patch was only achieved in 61%.

Increased condylar growth after experimental relocation of the glenoid fossa

Attempts to increase mandibular growth by the stimulation of condylar proliferative activity, either experimentally or with functional appliances in humans, have led to controversial results. The aim of this study was to measure changes in proliferative activity in the mandibular condyle after steady experimental posterior relocation of the glenoid fossa in the rabbit without actively interfering with normal masticatory action. The method differed from most previous experimental procedures, which force the mandible anteriorly to stimulate functional appliance therapy. Twelve 5-day-old rabbits underwent gluing of the interparietal, temporoparietal, and lambdoidal sutures. Three experimental and three control rabbits were injected with tritiated thymidine at 10, 15, 20, and 30 days and were killed after 2 h for histological and autoradiographic examination. The total number of labeled cells in the prechondroblastic layer was higher in the experimental group, the difference being greatest in the 20-day-old rabbits. The highest proliferative activity in the experimental group was found in the area immediately posterior to the articular contact surface. There was a tendency for the cartilage layers to be thicker in the experimental group, especially in the extreme anterior segments of the condyle.

Effect of food consistency on the shape of the articular eminence and the mandible. An experimental study on the rabbit

The aim of this investigation was to ascertain what changes masticatory function could elicit in the shape of the articulating surface and the growth of the mandible in a growing rabbit. Forty-seven rabbits were divided into two groups, a control group fed whole pellets and a 'soft' group fed softened pellets and having their incisors shortened once a week. All the rabbits were killed at the age of 50 days and roentgenographed, after which the heads were freed of soft tissues, and the shape of the articulating eminence, the dimensions of the mandible and the maxilla, and intermaxillary relations were measured. The articulating surface of the glenoid fossa was steeper in the soft group, the lower border of the articulating eminence was located more inferiorly, and the mandible was more retrognathic. It is concluded that the difference in functional stress affects the shape of the articular eminence and the intermaxillary relationship. When the condyle is functioning more on the eminence, the latter becomes flatter, and the mandible moves forwards.

Clinical and radiological comparison of perivascular and transarterial techniques of axillary brachial plexus block

The perivascular technique of axillary brachial plexus block results in incomplete block of radial and musculocutaneous nerves in 10-20% of patients. With the transarterial technique and a large dose of mepivacaine, success rates of 99% have been reported. We have compared the clinical efficacy of these techniques in 50 patients using 1% mepivacaine 45 ml with adrenaline. If required, the block was supplemented with additional blocks of single nerves or i.v. alfentanil. Additionally, eight patients in each group were studied with computed tomography after contrast medium was added to 0.5% bupivacaine 40 ml. There were no statistically significant differences in sensory or motor block between the groups at 20 min or in the plasma concentrations of mepivacaine measured 0-45 min after injection. In the CT scans, both proximal and distal spread of the contrast medium were more common after perivascular than after transarterial block. The distribution of the contrast medium was not related to the efficacy of the block.

Technical and light microscopic comparison of four different small-diameter catheters used for continuous spinal anesthesia

BACKGROUND AND OBJECTIVES

Recently several manufacturers developed ultra-thin catheters for continuous spinal anesthesia. Their use may be associated with technical problems.

METHODS

Four spinal catheters [Preferred Medical 28-gauge and 32-gauge (polyurethane), Kendall CoSpan 28-gauge (nylon), and Microspinal 32-gauge (polyimide)] were compared in 41 patients who underwent knee or hip operations. Difficulties in using the catheters were recorded, and after their removal, the catheters were examined by light microscopy.

RESULTS

The insertion of the 28-gauge catheters was always successful. However, five of 11 of the 32-gauge polyurethane and one of ten of the 32-gauge polyimide catheters could not be inserted. Plain 0.5% bupivacaine (2-6.5 ml) was administered, and the median pinprick analgesia level varied between T4 (28-gauge nylon) and T7 (other groups). During removal, one of ten of the 28-gauge nylon, four of ten of the 28-gauge polyurethane, and all six 32-gauge polyurethane catheters stretched. Two of six of the 32-gauge polyurethane catheters broke, but no fragment remained in any patient. Microscopic examination revealed deposits of fibrinous material on the tips of all polyurethane and polyimide catheters and on one nylon catheter. One polyimide catheter ruptured 15 cm from the tip. No signs of tearing or lost pieces of catheter material were observed by light microscopy.

CONCLUSION

The use of the 32-gauge polyurethane catheter was associated with problems that limit its clinical usefulness. Nylon and polyimide catheters with stainless steel stylets were more resistant to stretching. The nylon catheter was most resistant to adhesion of fibrinous material.

Haemodynamic changes during spinal anaesthesia with slow continuous infusion or single dose of plain bupivacaine

Forty elderly patients, scheduled for orthopaedic surgery of the hip or knee were studied. Twenty patients received a single-dose spinal anaesthesia with 3 ml of plain 0.5% bupivacaine (SDSA group). Twenty patients received continuous spinal anaesthesia using a 32- or 22-gauge catheter. A bolus of 1.0 ml of plain 0.5% bupivacaine was given to ten patients and 0.5 ml to another ten, continued by an infusion at a rate of 2 ml/h. The spread of analgesia and haemodynamic changes (central venous pressure, arterial pressures, need for sympathomimetic medication) were registered. The mean dose of bupivacaine was 2.9 ml (range 1.5-5 ml) in the CSA group (3.0 ml in the SDSA group). Eight patients in the CSA group needed medication for pain during surgery compared to five patients in the SDSA group (n.s.). The median level of pinprick analgesia at 60 min was T11 in the CSA and T6.5 in the SDSA group (P less than 0.01). The mean maximum decreases in CVP and MAP were quite similar in the CSA and SDSA group (2.1 vs 2.8 mmHg (0.3 vs 0.4 kPa) and 17 vs 21 mmHg (2.3 vs 2.8 kPa), respectively) (n.s.). Six patients in the SDSA group and four patients in the CSA group needed sympathomimetic medication. It is concluded that titration of bupivacaine for spinal anaesthesia caused only minor haemodynamic changes which were similar to those after single-dose spinal bupivacaine.

Effect of speed of injection of 0.5% plain bupivacaine on the spread of spinal anaesthesia

We have studied the influence of two different speeds of injection on the spread of spinal anaesthesia of bupivacaine in 40 orthopaedic patients. In a random order, 0.5% plain bupivacaine 3 ml was administered in 10 or 180 s into the subarachnoid space using a 27-gauge needle with the patients in a lateral horizontal position. The slower speed produced a higher spread of spinal anaesthesia (median difference 2.5 segments, P < 0.05).

Tooth surface loss and associated factors among factory workers in Finland and Tanzania

The relative importance of various factors in the occurrence of tooth surface loss was explored in a, cross-sectional study using blind dental examinations. Two samples were drawn; one from Finland, comprising 186 workers from four factories and another from Tanzania of 180 workers from two factories. Among the 326 dentate individuals who participated, 164 were exposed to acid fumes and 162 were not. In Finland, people with tooth surface loss were older and smoked cigarettes less frequently. In Tanzania, those with tooth surface loss were also older and the proportion of subjects with the condition was significantly higher among people not using a commercial toothbrush and those exposed to acids. Among the Tanzanians, exposure to acids increased the probability of tooth surface loss to a high level of significance, and increasing age increased its probability, both among the Finns and the Tanzanians. Both anterior and posterior teeth were affected. It can be concluded that if the exposure to acids from the air breathed is high, the probability of tooth surface loss will increase. It seems that explanatory factors for tooth surface loss from one society cannot be extrapolated to another.

Technical problems associated with the use of 32-gauge and 22-gauge spinal catheters

Interest in the use of continuous spinal anaesthesia (CSA) has recently increased because of the availability of new, extremely thin catheters. In this study the use of 32-gauge (G) catheters was compared with 22-G catheters in operations on the lower limb and for the administration of intrathecal morphine in the postoperative period in 42 elderly patients. CSA succeeded in 34 cases and 8 patients were anaesthetised with a single-shot spinal method. No general anaesthesia was needed. Technical problems with the subarachnoid puncture with the 19-G needle caused two failures in the 22-G group. In a group of 20 patients, there were five failures with the 32-G catheter, as opposed to one failure with the 22-G catheter in a group of 20 patients. Associated with morphine injection through the 32-G catheter, the syringe or connector was inadvertently disconnected in four cases and a tear of the catheter wall was observed in one case. Such problems did not occur with the 22-G catheter. Postdural puncture headache did not occur, and there was no difference in the incidence of patient-reported postoperative complications between the two groups. It is concluded that both the insertion and maintenance of the thin (32-G) subarachnoid catheters are associated with more technical problems than the 22-G catheter.

Prediction of the spread of repeated spinal anaesthesia with bupivacaine

We have studied in 56 patients the predictability of spread of repeated spinal anaesthesia in the same patient on the basis of a previous block. With plain 0.5% bupivacaine, prediction of the second block was accurate. A significantly higher or lower spread of analgesia than in the previous block was achieved when plain 0.5% bupivacaine was administered using a modified technique--sitting position or lower interspace, respectively. When hyperbaric 0.5% bupivacaine was injected instead of plain solution for the second block using a similar technique, no baricity-related correlation was found between the first and second blocks. Change in technique did not reduce interindividual variation in the spread of analgesia. We conclude that individual anatomical properties may play a more important role than, for example, baricity in subarachnoid distribution of a local anaesthetic solution.

Weaning and the histology of the mandibular condyle in the rat

Eighty-eight Long Evans/Turku rats were used in the study. The effect of the articulatory function on the mandibular condyle was observed histologically during normal growth, when the rat is changing its diet from milk to whole pellets as a part of weaning. Six animals each were killed at the age of 10, 15, 20, 25, 30, 35, 40 and 50 days for histological tissue processing. For further information, 30 animals were fed a soft diet (6 animals each were killed at the age of 25, 30, 35, 40 and 50 days), and 10 animals were fed hardened pellets (2 animals each were killed at the ages of 25, 30, 35, 40 and 50 days). An even and regular transition from mesenchymal cells via immature chondroblasts into mature chondroblasts and hypertrophied chondrocytes was found at 10, 15 and 20 days during normal growth and also at 25, 30, 35, 40 and 50 days when animals were fed a soft diet. This maturing process appeared to be disturbed at the age of 25, 30, 35 and 40 days in the superior aspect of the condyle in animals fed ordinary pellets. The density of the mesenchymal cell layer was decreased, and the amount of intercellular matrix seemed to be evaluated in mesenchymal and intermediate cell layers. These features were later manifest deeper in the cartilage as acellular regions and as cell clusters. The changes were similar but more severe when the animals were fed hardened pellets.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of continuous interscalene brachial plexus block on diaphragm motion and on ventilatory function

Interscalene block may cause phrenic nerve block and decreased diaphragmatic motion. We evaluated the effect of continuous interscalene block on ventilatory function and diaphragmatic motion. We studied ten patients scheduled for surgery or manipulation of the shoulder. Preoperatively, the patients underwent spirometry and double-exposure chest radiography. They received an interscalene block with 0.75% bupivacaine. Thereafter, 0.25% bupivacaine was infused into the interscalene space for 24 h. Spirometry was repeated three times and double-exposure radiography twice. The maximal inspiratory and expiratory pressures were measured repeatedly. Haemoglobin oxygen saturation (SPO2) was monitored with pulse oximetry. The block provided adequate anaesthesia for surgery or manipulation. All patients had a marked ipsilateral paresis of the diaphragm in the radiographs 3 h after the initial block. Twenty-one hours later five patients had diaphragmatic motility comparable to the situation before the block. In the other five patients, the amplitude of diaphragmatic motility on the side of the block was only 4-37% of the values before the block. All patients had a clear reduction in forced vital capacity (FVC), forced expiratory volume in 1s (FEV1) and peak expiratory flow (PEF) 3 and 8 h after the block without signs of dyspnoea. In conclusion, in all our patients interscalene block caused an ipsilateral hemidiaphragm paresis, which in five of ten patients persisted until the end of the continuous block.