Showing papers in "Acta Anaesthesiologica Scandinavica in 1985"

Epidural morphine for postoperative pain: experience with 1085 patients.

Abstract: A prospective study of the effect and side-effects of epidural morphine for pain relief in 1085 patients after thoracic, abdominal, urologic, or orthopaedic surgery was performed. Morphine chloride was diluted in saline or bupivacaine and administered through an epidural catheter placed at a segmental level appropriate for the type of surgery. The initial dose was 4 or 6 mg morphine and supplementary doses were given when needed to obtain complete freedom from pain during deep breathing or nursing care. The total dose of epidural morphine from end of surgery until the next morning varied from 4 to 18 mg. 97% of hip arthroplasty patients, 91% of prostatectomy patients and thoracotomy patients, 90% of patients after major lower extremity surgery and 88% of patients after laparotomy were completely satisfied with the postoperative course. For hip arthroplasty and major extremity surgery, an initial dose of 4 mg of epidural morphine was as effective as 6 mg. After prostatectomy, laparotomy, and thoracotomy, an initial dose of 6 mg gave significantly better effect than 4 mg. Pruritus occurred in 11%, nausea or vomiting in 34%, and respiratory depression in 0.9% of the total patient population. Urinary retention occurred in 42% of patients not having urinary catheters in place. Postoperative nausea or vomiting was more frequent in women than in men (P less than 0.001). There was a higher incidence of nausea or vomiting in men experiencing pain than in men who were completely pain-free after abdominal surgery (P less than 0.001). Respiratory depression was rare and occurred as a gradually decreasing respiratory rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential effects of epidural morphine in the treatment of cancer-related pain.

Abstract: Fifty-five patients with pain associated with cancer were selected for long-term treatment with epidural morphine. Patients who had more than one type of pain within the same region were specially analysed concerning differential analgesic effects of the treatment, i.e. the patients served as their own control. Twenty-eight of the 55 patients became pain free. In 21 patients alleviation of pain was complete only for one or two of several types of pain within the same area with a certain dose of epidural morphine. In six patients the treatment failed. An analysis revealed that the best response was obtained when the pain was continuous and originated from deep somatic structures. In co-existing continuous visceral pain or intermittent somatic pain originating e.g. from a pathological fracture, the outcome of the treatment was variable. Cutaneous pain, pain classified as neurogenic, and intermittent pain due to intestinal obstruction was only occasionally relieved. Ten of the patients had co-existing pain of non-malignant origin and none of them was helped for that pain. The variable response to epidural morphine may indicate that different types of pain-producing stimuli engage different kinds of receptors which differ in affinity to morphine in the spinal fluid; it is also possible that some pain-mediating systems are non-responsive to opiates.

A Controlled Study on the Effect of Epidural Analgesia with Local Anaesthetics and Morphine on Morbidity after Abdominal Surgery

Abstract: A hundred patients scheduled for elective abdominal surgery were randomized to either general anaesthesia (low-dose fentanyl) and systemic morphine for postoperative pain or combined general anaesthesia and epidural analgesia with etidocaine 1.5% intraoperatively (T4-S5) and bupivacaine 0.5% 5 ml/4 h for 24 h and morphine 4 mg/12 h for 72 h. Postoperative pain was better controlled by the epidural regimen (P less than 0.0001). We found no significant reduction in postoperative mortality (6% to 2%), pneumonia (28% to 20%), cardiac dysrhythmia (10% to 5%) and wound complications (14% to 11%) by the epidural analgesic regimen. The incidence of deep venous thrombosis (125I-fibrinogen scan) was 32% after general anaesthesia and low-dose heparin and 34% after epidural analgesia with no prophylactic antithrombotic treatment (P greater than 0.9). Postoperative weight loss and decrease in serum-albumin and serum-transferrin, as well as the reduction in haemoglobin and the need for postoperative transfusions, were similar in the two groups. Convalescence, as assessed by postoperative fatigue, restoration of bowel function (flatus, bowel movement and food intake) and the time until the patients were self-aided at their preoperative level, was not reduced by epidural analgesia. Since 50% of the patients in each group suffered from one or more of the above-mentioned postoperative complications, this epidural regimen was not effective in reducing postoperative morbidity after major abdominal surgery despite the achievement of adequate pain relief.

Methemoglobinemia associated with a prilocaine-lidocaine cream and trimetoprim-sulphamethoxazole. A case report.

Abstract: A case of moderate methemoglobinemia in an infant treated with trimetoprim-sulphamethoxazole and a topical mixture of lidocaine and prilocaine is described. The possibility of an additive interaction between sulphamethoxazole and prilocaine is discussed, as well as the mechanism and therapy of methemoglobinemia.

Evaluation of central venous catheter thrombogenicity.

Abstract: Four studies were performed to evaluate the thrombogenicity of different central venous catheter materials. Two of these studies consisted of evaluating the amount of platelet deposition on different catheter materials, firstly in vitro and then in vivo using dogs. In these studies, 51-chromium was used to label the platelets. In the following study, the volume of clot and the degree of fibrin sheath were determined by placing catheters in both arteries and veins of dogs for two to four weeks before removing the vessels and performing a quantitative analysis. For the fourth study, indium labelled platelet deposition with scintillation counting was performed on six dogs in whom catheters had been placed in the femoral and carotid arteries. The vessels in three of these animals were removed 48 hours after imaging was completed to correlate the scintigraphic findings with a quantitative analysis of the clot and fibrin sheath on each catheter. There was a high degree of correlation between all these studies. The most consistently thrombogenic catheter material was polyurethane, and the least thrombogenic catheter material was polyurethane coated with hydromer. Silicone was the next least thrombogenic material examined.

Potential Anti‐Thrombotic Effects of Local Anaesthetics due to their Inhibition of Platelet Aggregation

Abstract: The aim was to study the possible anti-aggregating effects of local anaesthetics on platelets stimulated by physiological doses of adenosine-diphosphate and collagen. Platelet-rich plasma was therefore incubated in an aggregometer with lidocaine, bupivacaine or tocainide in various concentrations and for different incubation times. It was found that of the local anaesthetics tested, lidocaine was the most effective anti-aggregating compound. Furthermore, the longer the incubation time with the different local anaesthetics, the more efficient the anti-aggregating effect. These results may have clinical implications, and they may be one of the explanations for the lower incidence of thromboembolism in patients operated on under lumbar epidural anaesthesia.

Effects of adjuvants to local anaesthetics on their duration. III: Experimental studies of hyaluronic acid

Abstract: The effects of addition of hyaluronic acid (sodium hyaluronate, Healon) to different local anaesthetics of the amide type on the duration of sensory or motor blocks following various regional anaesthetic procedures were studied in animal experiments. In the rat infra-orbital nerve block model, the addition of 0.1-0.5% hyaluronic acid (HA) to 2% prilocaine increased the duration of sensory block of varying degrees in a dose-dependent way by up to 500% of values obtained with plain prilocaine. The duration of degree 5 blocks produced by 0.5% etidocaine and 0.5% bupivacaine was also significantly prolonged when 0.4% HA was included to 206% and 282% of control, respectively, while blocks induced by 2% lidocaine were prolonged to 123% of control. The duration of motor block following spinal anaesthesia in the mouse was prolonged in a dose-dependent way when HA was added to prilocaine, bupivacaine and etidocaine. For solutions containing 0.4% HA, prolongations to 254%, 166% and 134% of control, respectively, were obtained. A concomitant increase of latency to onset of block and failure rate occurred with increasing concentrations of HA. The duration of corneal anaesthesia in the rabbit increased by 57% and 44% when 0.3% HA was added to prilocaine and bupivacaine, respectively. The duration of infiltration anaesthesia was not affected by the addition of HA to the local anaesthetic solutions. Addition of HA had no effect on the onset, depth and duration of prilocaine-induced block of the nervous transmission in vitro. The duration of infra-orbital nerve block and spinal anaesthesia shows a significant relation to the relative viscosity of the local anaesthetic solution.

Analysis of 13800 Subclavian Vein Catheterizations

Abstract: During the period 1974-1983, 13 857 subclavian or internal jugular vein catheterizations were analysed in the same hospital. The data on the catheterizations have been collected prospectively in the hospital computer. In 93% of the cases, catheterization was subclavian vein cannulation performed through the infraclavicular route. In 15% of the cases the catheter position was not ideal, verified with x-ray; e.g. the catheter tip was turned into the internal jugular vein. Of the catheters 70% were kept in place for less than 7 days, and only 6% for over 2 weeks. More than one catheterization was required in 26% of the cases during the same hospitalization. Recatheterization is an important prophylactic measure for preventing septic complications, if suspicion of infection arises. In 5% of the cases, some complications occurred, but they were mostly minor, such as haematoma at the puncture site. More serious complications were 19 pneumothoraces (0.1%). The results suggest that subclavian vein catheterization is a fairly safe method for large-scale use in a hospital, if only a limited group of physicians perform it. Certain precautions should, however, be taken.

Circulatory changes during high thoracic epidural anaesthesia--influence of sympathetic block and of systemic effect of the local anaesthetic.

Abstract: Circulatory changes during high thoracic epidural anaesthesia (TEA) were studied in nine healthy volunteers by means of echocardiography and systolic time intervals. The subjects also underwent a physical work test with bicycle ergometry. To evaluate the systemic effect of the local anaesthetic (bupivacaine), the same subjects were investigated 3 weeks later when a corresponding dose of the local anaesthetic was injected intramuscularly instead of epidurally. On the first occasion, after baseline measurements an epidural catheter was inserted at T4 level and 5 ml of 0.5% bupivacaine were injected. This volume led to sensory block within dermatomes T1-T5. On the second occasion all subjects received 8 ml of 0.5% bupivacaine intramuscularly. Heart rate (HR) and systolic blood pressure decreased during TEA, both at rest and during exercise. Following i. m. injection, HR decreased at rest but remained unchanged during exercise. The systolic blood pressure was not affected but the diastolic blood pressure increased during the exercise test. After administration of TEA, stroke volume (SV) decreased 22% and cardiac output (CO) 33%. Following i. m. injection of bupivacaine, SV decreased 8% and CO 20%. The pre-ejection period/left ventricular ejection time ratio increased 23% during TEA and 16% after i. m. injection. The results indicate that the circulatory changes did not seem to be caused entirely by the cardiac sympathetic block, but were due partly to the systemic effect of bupivacaine.

Bladder function in spinal anaesthesia.

Abstract: Spinal anaesthesia with bupivacaine (22.5 mg) or with a glucose-containing solution of bupivacaine (20 mg) or tetracaine (15 mg) was given to 21 patients allocated randomly to these three groups. A urodynamic study was performed by CO2 cystometry. It consisted of recording of first sensation of bladder filling, sensation of full bladder, strength of maximal detrusor contraction, bladder capacity and urethral pressure. At the same time, using a quantitative method for measuring muscle strength, the motor block was evaluated for three separate movements--hip flexion, knee extension and plantar flexion of the big toe. After the spinal injection, the micturition reflex was rapidly blocked. One minute after the injection, eight patients experienced no strong desire to void when the bladder was overfilled, and 5 min after the injection bladder paralysis was present in most patients. The length of time from spinal injection to complete recovery of detrusor strength was 7-8 h and did not differ significantly between the three groups. The level of analgesia lay at or caudal to L5 when the detrusor strength returned. On the average, sensibility (pin-prick) in the sacral segments returned simultaneously with or somewhat earlier than complete recovery of detrusor strength. The muscle strength in the lower limbs was fully restored 40-140 min, on average, before the detrusor strength had completely recovered. There was good correlation between the time of full restoration of hip flexion and detrusor strength in the bupivacaine groups. Urethral pressure was reduced by a mean of 48% and returned to normal either at the same time as or slightly before complete recovery of detrusor strength.(ABSTRACT TRUNCATED AT 250 WORDS)

Pain on i.v. injection of propofol (ICI 35 868) in emulsion formulation. Short communication.

Abstract: Pain on injection of three anaesthetic induction agents, thiopentone, methohexitone and propofol (diisopropyl phenol), administered into a vein on the dorsum of the hand or wrist, was studied in 32 premedicated patients undergoing elective surgery. The pain was rated as none, mild or severe. A 1% emulsion formulation of propofol (ICI 35 868) (2 mg kg-1) and methohexitone (2 mg kg-1) induced pain significantly more often, in 100% and 80% of patients, respectively, than thiopentone (4 mg kg-1), 0%. The pain was rated as severe more often in patients receiving propofol (67%, P less than 0.01 vs thiopentone) than in those anaesthetized with methohexitone (20%) or thiopentone (0%). It is concluded that the fat emulsion form of propofol, when injected into a peripheral vein, frequently induces severe pain.

HLA antigens in patients with unexplained hepatitis following halothane anesthesia.

Abstract: We examined HLA-A,B,C and DR locus antigens in 38 Japanese patients who had recovered from halothane hepatitis. The patients were divided into two subgroups, i.e. jaundice and non-jaundice groups, because the clinical features were quite different in each. DR2 was positive in 14 (58.3%) of 24 patients with jaundice, compared with 281 (33.6%) of the 837 Japanese healthy controls (chi-square with Yates' correction = 5.30, relative risk = 2.77, P less than 0.025). Conversely, Bw44 was increased in non-jaundice patients (50.0%), compared with 157 (12.7%) of the 1234 Japanese healthy controls (chi-square with Yates' correction = 13.75, relative risk = 6.86, P less than 0.001). The haplotype frequency (Hf) of Aw24-Bw52-DR2 was high in the patients with jaundice (Hf = 0.2362), while it was zero in the patients without jaundice (P less than 0.0042). These data suggest that the two groups of halothane hepatitis have different genetic backgrounds.

Inhibition of human leukocyte metabolism and random mobility by local anaesthesia.

Abstract: Hexose-monophosphate shunt (HMS) activity, myelo-peroxidase-(MPO)-mediated iodination and random mobility in human polymorphonuclear leukocytes (PMNs) were studied in the presence of lignocaine. Incubating the PMNs with 0.1% lignocaine during phagocytosis inhibited the 14CO2 produced from glucose-1-14-C via the HMS shunt by 33%. On increasing the concentration of lignocaine, a dose-dependent inhibition was noted. The MPO-mediated iodination was inhibited by 73% in the presence of 0.1% lignocaine, and complete inhibition took place when the concentration was increased to 0.5%. The random mobility of leukocytes was studied by an opto-electronic technique. In the presence of 0.5% lignocaine, all leukocytes examined were completely immobilized; in the presence of 0.1% lignocaine immobilization took place within 45-65 min.

Caudal or dorsal nerve block? A comparison of two local anaesthetic techniques for postoperative analgesia following day case circumcision.

Abstract: Fifty boys presenting for day case circumcision were allocated randomly to receive either caudal analgesia or dorsal nerve block (DNB) to provide postoperative pain relief. Analgesia was assessed by a single, unbiased observer utilising a three-point scale. Subsequently, parents completed a simple questionnaire. Subjects in the DNB group micturated earlier (P less than 0.05) and stood unaided earlier (P less than 0.025) than patients in the caudal group. The incidence of vomiting was significantly lower in the DNB group (P less than 0.05). There was no significant difference in the duration of analgesia, although that produced in the DNB group tended to wane sooner. It is concluded that DNB provides satisfactory analgesia following circumcision and has specific advantages when compared with caudal analgesia.

Precurarization with Vecuronium and Pancuronium in Awake, Healthy Volunteers: The Influence on Neuromuscular Transmission and Pulmonary Function

Abstract: The influence of pretreatment with pancuronium and vecuronium on the neuromuscular transmission was compared in 24 healthy, awake, non-premedicated volunteers using train-of-four (TOF) nerve stimulation and measurement of respiratory frequency, vital capacity, inspiratory force and peak expiratory flow (PEF). The subjects were randomly allocated to one of three groups. Each subject received one dose of pancuronium and one dose of vecuronium: Group I pancuronium 0.01 mg/kg and vecuronium 0.005 mg/kg; Group II pancuronium 0.01 mg/kg and vecuronium 0.01 mg/kg and Group III pancuronium 0.01 mg/kg and vecuronium 0.015 mg/kg intravenously. The median TOF ratio decreased significantly in Groups I and II following both pancuronium and vecuronium. The TOF ratio following vecuronium in Group II was significantly lower compared to the TOF ratio following vecuronium in Group I. Only PEF decreased significantly in Group I following pancuronium and in Group II following both pancuronium and vecuronium. There was no significant difference between Group I and Group II regarding the number of subjects with signs or symptoms of partial neuromuscular blockade. Following vecuronium 0.005 mg/kg, one subject was unable to swallow and the twitch height decreased to 0.25. In Group II one subject was unable to lift her head and had difficulty in swallowing following pancuronium 0.01 mg/kg. Only four subjects entered Group III because of an unacceptably high frequency of signs and symptoms of partial neuromuscular blockade and a decrease in median TOF ratio to 0.64 following vecuronium. The subjects felt it difficult to swallow, and one subject could just sustain head lift for 10 s following vecuronium 0.015 mg/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Reduction of the slow inward current of isolated rat ventricular cells by thiamylal and halothane.

Abstract: The barbiturates and halothane exert a negative inotropic effect on the myocardium. A reduction in the slow inward current, carried mainly by calcium ions, is an important factor for the underlying mechanism because the calcium current during the action potential provides the calcium ions for accompanying contraction, supplies Ca ions to the sarcoplasmic reticulum for subsequent contractions, and induces Ca release from the store site. It has been suggested that reduction in the slow inward current caused by anesthetics is indicated by depression of the slow action potential of the partially depolarized myocardium. In order to assess directly the effect of anesthetics on the slow inward current, we carried out voltage clamp experiments with single isolated rat ventricular cells obtained by an enzymatic dissociation method. Thiamylal (10(-4) mol . l-1) and halothane (1%) decreased the slow inward current to 60 +/- 5% (mean +/- s.d., n = 8) and to 65 +/- 10% (mean +/- s.d., n = 8) of the control value, respectively, without changing the configuration of the current-voltage curve. The results provide further evidence for anesthetic reduction of the slow inward current of the myocardium, and suggest that the negative inotropic effect is at least partly due to the reduction in that current.

Effects of adjuvants to local anaesthetics on their duration. IV. Effect of hyaluronic acid added to bupivacaine or prilocaine on the duration of nerve blockade in man.

Abstract: A randomized study of the duration of ulnar nerve blockade induced with 2% prilocaine or 0.5% bupivacaine with and without 0.4% hyaluronic acid was performed in volunteers. In contrast to results in experimental animals, the addition of hyaluronic acid to the local anaesthetic solution did not affect the duration of sensory nerve block.

Sciatic nerve block: a new lateral approach.

Abstract: The currently available methods for local anaesthetic block of the sciatic nerve are difficult to perform. Here we describe a new and easier technique for the block. The sciatic nerve is approached from the lateral side of the thigh with the patient lying supine and is identified by simple anatomical landmarks with the help of a nerve stimulator. The technique was found to be safe and effective in over 100 cases. It can be learnt quickly and is easily remembered.

Skin conductance responses during spinal analgesia.

Abstract: Skin conductance responses (SCR, "sympatho-galvanic reflex") were measured before and during spinal analgesia in 17 patients scheduled for transurethral surgery. Responses were provoked by standardized electrical stimulation over the clavicle opposite to the recording side; alternatively, a short deep breath, pinching, verbal stimuli or sharp sounds were used. Measuring sites (two electrodes 6 cm apart) were the hand, levels T5, T9, T12-L1 and the foot. Spinal analgesia reached a median cephalad level of T4 (mean T4, range +/- 3 segments) 20-25 min after injection. SCR was markedly depressed in the foot in 15 of 17 patients, at T12-L1 in 12 of 17, at T9 in 10 of 17, at T5 in 9 of 16 and in the hand in 6 of 17. Total abolition of the SCR in the foot was accomplished in only seven cases and sympathetic activity reappeared long before regression of analgesia or motor blockade was observed. In four cases of five with an analgesic level T1-T2, the SCR was preserved in the hand. No consistent correlation between blood pressure change and SCR-change was seen. The conclusion from this study is that preganglionic sympathetic B-fibres are more difficult to block than A-fibres during spinal analgesia. The duration of sympathetic blockade was far shorter than analgesia and motor blockade. Thus, sympathetic blockade during spinal analgesia seems to be far less extensive than that described in the literature.

Comparison of Adrenaline and Phenylephrine in Out‐of‐Hospital Cardiopulmonary Resuscitation: A Double‐Blind Study

Abstract: Phenylephrine, a strong alpha-adrenergic receptor-stimulating agent, was compared with adrenaline in 65 patients with out-of-hospital cardiac arrest, in a double-blind study. The resuscitation was performed by the physician-staffed Prehospital Emergency Care Unit of Helsinki University Central Hospital. The patients received either 1.0 mg of phenylephrine or 0.5 mg of adrenaline i.v. in the treatment of fine ventricular fibrillation, asystole or electromechanical dissociation. If two doses of either drug did not restore circulation, 0.5 mg of known 0.01% adrenaline was given i.v., maximally twice. In the adrenaline group, which consisted of 36 patients with a mean age of 61 years, 10 patients (28%) were successfully resuscitated. The phenylephrine group consisted of 29 patients with a mean age of 62 years. In this group nine patients (31%) were successfully resuscitated. The two groups were comparable regarding their apnoea-times, and there was no difference in the need for extra adrenaline between the groups. No adverse effects, such as hypertension or bradycardia, were noted in the patients treated with either adrenaline or phenylephrine, nor did the overall rate of successful resuscitation fall during the test period. It is concluded that phenylephrine seems as effective as adrenaline in the treatment of cardiac arrest, but further studies seem warranted.

Effects of Three Anaesthesia Methods on Haemodynamic Responses Connected with the Use of Thigh Tourniquet in Orthopaedic Patients

Abstract: Haemodynamic changes were studied in 51 patients undergoing orthopaedic surgery of the lower extremity, including exsanguination and thigh tourniquet for longer than 60 min. The patients were randomly divided into three anaesthesia groups: general anaesthesia (including enflurane), epidural anaesthesia (20 ml 0.5% bupivacaine) and spinal anaesthesia (3 ml 0.5% bupivacaine). During the study, five epidural and one spinal patient excluded from haemodynamic comparison required general anaesthesia because of pain from the surgery or ischaemia. In the general anaesthesia group, there was a rise in either systolic or diastolic arterial pressure of over 30% of the control value in 8/15 patients. In the spinal anaesthesia patients, there was a transient rise above 30% in only one patient out of 15 and no rise in the 15 epidural group patients. On the other hand, 11/15 of the epidural patients needed additional analgesics and/or sedation for pain or restlessness. The mean rise in the haemodynamic parameters including CVP was small on inflation of the tourniquet cuff; on deflation there was a mean decrease in CVP of 1-3 cmH2 (0.1-0.3 kPa), the maximum decrease being 8 cmH2O (0.8 kPa). The mean decrease in systolic arterial blood pressure ranged from 2 to 14 mmHg (0.27 to 1.87 kPa) when the cuff was deflated.

Hypoxic pulmonary vasoconstriction in the human lung: the effect of prolonged unilateral hypoxic challenge during anaesthesia.

Abstract: The influence of time on the pulmonary vasoconstrictor response to hypoxia was studied in six subjects during general anaesthesia and artificial ventilation prior to elective surgery. The lungs were intubated separately with a double-lumen bronchial catheter. After preoxygenation of both lungs for 30 min, the test lung was rendered hypoxic for 60 min by ventilation with 5% O2 in N2, with the control lung still being ventilated with 100% O2. Cardiac output was determined by thermodilution, and the distribution of blood flow between the lungs was assessed from the excretion of a continuously infused poorly soluble gas (SF6). The fractional perfusion of the test lung decreased from 53% to 25% of cardiac output within the first 15 min of unilateral hypoxia. The pulmonary artery mean pressure increased by 14% and the pulmonary vascular resistance (PVR) of the test lung increased by 54%. Venous admixture increased from 21% to 39% of cardiac output, while the "true" shunt was maintained at about 15%. Arterial oxygen tension (Pao2) fell from 45 kPa to 12 kPa. Prolonging the unilateral hypoxic challenge caused no further change in the redistribution of the pulmonary blood flow, but cardiac output and pulmonary artery mean pressure continued to increase to 40%-50% above control values after 1 h of hypoxia. The PVR of the test lung remained unchanged. The findings suggest that there is an immediate vasoconstrictor response to hypoxia in the human lung and that there is no further potentiation or diminution, of the response during a 60-min period of hypoxia.

Influence of Pre-operative Treatment with Phenoxybenzamine on the Incidence of Adverse Cardiovascular Reactions during Anaesthesia and Surgery for Phaeochromocytoma

Abstract: The influence of pre-operative treatment with the alpha-adrenoceptor blocking agent, phenoxybenzamine, on the incidence of adverse cardiovascular reactions during anaesthesia and surgery for phaeochromocytoma was evaluated in a series of 62 patients. Fifty-one of them received pre-operative treatment with phenoxybenzamine and eight of these were also treated with beta-adrenoceptor blocking agents. The median final daily dose of phenoxybenzamine was 160 mg and the median period of treatment 23 days. The evening before surgery and in the early morning on the day of surgery, intravenous infusion of phenoxybenzamine was given to 42 of the patients. Eleven patients operated on between 1956 and 1963 received no specific pre-operative treatment and served as a reference group. The alpha-adrenoceptor blocking treatment resulted in a considerably smoother peroperative course, as evidenced by a statistically significant reduction in the incidence of excessive blood-pressure variations. The blockade was not complete since 69% of the patients had systolic peaks greater than 175 mmHg during surgery. Pre-operative blood transfusions did not significantly affect the incidence of hypotensive episodes. Pre-operative beta-adrenoceptor blockade did not reduce the incidence of peroperative arrhythmia. On the basis of our experience, we recommend that all phaeochromocytoma patients be treated pre-operatively with alpha-adrenoceptor blocking agents.

A Porcine Model of Early Adult Respiratory Distress Syndrome Induced by Endotoxaemia

Abstract: To study the pathophysiology of early adult respiratory distress syndrome (ARDS) induced by sepsis, spontaneously breathing pigs under ketamine anaesthesia were investigated. Twenty animals were infused i.v. with E. coli endotoxin (10 micrograms . h-1 . kg-1) over 6 h, and ten control animals received physiological saline. In the controls, cardiac output (Qt) and O2 delivery decreased slightly. There were no changes in pulmonary gas exchange, pulmonary haemodynamics or extravascular lung water (EVLW). The polymorphonuclear (PMN) leucocyte count gradually increased, while the platelet count decreased slightly. Endotoxin infusion caused profound deterioration of pulmonary gas exchange, a marked rise in pulmonary vascular resistance (PVR) and a moderate increase in EVLW. The pulmonary dysfunction was not attributable to the pulmonary oedema per se, whereas a "dry" ventilation/perfusion inequality played an important role. The "responders" (peak venous admixture greater than 20%; n = 14) were characterized by higher Qt and lower PVR than the "non-responders". Qt declined progressively, especially in non-survivors. O2 delivery decreased considerably. Metabolic acidosis probably indicated oxygen deficit. Eleven of 20 animals died during the observation period. Mortality was related more to the imbalance between O2 delivery and oxygen demand than to the deterioration in pulmonary gas exchange. The PMN count decreased markedly while the gradual decline in platelet count was similar to that in the controls. Lung microscopy revealed PMN accumulation in the microvasculature, moderate interstitial oedema and microvascular blood stasis. Our porcine model, which closely mimics early ARDS in man, will be useful in further studies of the pathophysiological pathways and the treatment of this syndrome.

A Method for Epiduroscopy and Spinaloscopy Presentation of Preliminary Results

Abstract: A method for endoscopic observation of the epidural space, epiduroscopy, and the subarachnoid space, spinaloscopy, in the lumbar region is described using the Olympus Selfoscope SES 1711 S. The preliminary results of 30 consecutive attempts at epiduroscopy on randomly chosen autopsy cases, with 28 successes, are presented. Five spinaloscopies were performed on the same material. The results justify the conclusion that epiduroscopy and spinaloscopy are methods that can be used for study of individual variation of the contents of the lumbar epidural and subarachnoid spaces.

Spinal cord and cerebral blood flow responses to subarachnoid injection of local anesthetics with and without epinephrine.

Abstract: Subarachnoid anesthesia with lidocaine, mepivacaine, or tetracaine with and without added epinephrine (1:100 000) produced no demonstrable changes in average cerebral (CBF) or segmental spinal cord blood flow (SCBF) in 38 cats anesthetized with pentobarbital. Blood flow was measured by the injection of radioactive microspheres. Seven groups of cats received either lidocaine 15 mg, lidocaine 15 mg with epinephrine, mepivacaine 10 mg, mepivacaine 10 mg with epinephrine, tetracaine 5 mg, tetracaine 5 mg with epinephrine, or saline with epinephrine 1:100 000. Mean arterial pressure (MAP) decreased significantly (P less than 0.05) in Groups I-VI. Added epinephrine had no effect on the decrease in MAP. Amplitude of the somatosensory cortical evoked response decreased significantly in Groups I-VI, but did not change from control in Group VII. No significant change in CBF or SCBF was demonstrated in any group at any time. Plasma lidocaine and mepivacaine levels were significantly less at 5 min after subarachnoid injection in the groups receiving epinephrine compared to those not receiving epinephrine (P less than 0.05). The data appear to support the hypothesis of a vasoconstrictive reduction in systemic absorption of intrathecal local anesthetics, but suggest that significant segmental spinal cord ischemia does not occur. Maintenance of total flow in the face of a decrease in MAP suggests that autoregulation in brain and spinal cord may be maintained. Changes in regional SCBF or CBF may have been present but were not examined in this study. Further studies of brain and spinal cord blood flow dynamics, regional flow changes, and regulation of flow after intrathecal agents are necessary.

Effects of epidural analgesia on plasma catecholamines and cortisol in parturition.

Abstract: To assess the effect of epidural block on plasma catecholamines and cortisol during labour and delivery, plasma epinephrine, norepinephrine and cortisol levels were determined in 26 healthy parturients, all of whom delivered vaginally (18 received an epidural block, eight had meperidine 50 mg intramuscularly). We found a significant drop of plasma epinephrine and cortisol and no significant reduction of plasma norepinephrine 1 h after administration of epidural block compared to preblock values. Observing the data during the whole course of labour in correlation with cervical dilatation, in the control group, where the parturients received meperidine, all hormones rose progressively up to the moment of delivery. One hour after delivery the catecholamines returned to normal levels; cortisol returned more slowly. In the epidural group the increase of plasma epinephrine and cortisol was significantly inhibited but not that of norepinephrine.

Tolerance to nitrous oxide in volunteers.

Abstract: Nociception and loss of awareness during exposure to anaesthetic concentration of nitrous oxide (N2O) were studied in eight male medical students. The cold water nociception test, where a hand is immersed in 0 degree C stirred water, was used for measurement of nociception. At irregular intervals an auditory command was given to oppose two fingers, and this served to monitor consciousness. The selected inspiratory concentration of N2O used per individual was sufficient to induce a loss of consciousness for more than 2.5 min, within 10 min of exposure to N2O. This concentration of N2O varied from 60% to 80%. The experimental exposure to N2O lasted 3 h. In all volunteers significant antinociception was observed within 2 min of exposure to N2O. The maximal analgesic effect was observed between 20 and 30 min of exposure to N2O. The analgesic effect of N2O gradually decreased and was absent in all eight volunteers within 150 min. Two volunteers regained consciousness at 77 and 91 min of exposure, whilst still breathing 60 and 80% N2O. These results show that tolerance to antinociceptive effects of N2O in man rapidly develops and that awareness may occur in some volunteers during prolonged exposure to N2O.

CBF and CMRO2 during Continuous Etomidate Infusion Supplemented with N2O and Fentanyl in Patients with Supratentorial Cerebral Tumour. A Dose‐Response Study

Abstract: In 14 patients with supratentorial cerebral tumours with midline shift below 10 mm, CBF and CMRO2 were measured (Kety & Schmidt) during craniotomy. The anaesthesia was continuous etomidate infusion supplemented with nitrous oxide and fentanyl. The patients were divided into two groups. In Group 1 etomidate infusion of 30 micrograms kg-1 min-1 was used throughout the anaesthesia, and CBF and CMRO2 were measured twice. In this group CMRO2 (means +/- s.d.) averaged 2.31 +/- 0.43 ml O2 100 g-1 min-1 70 min after induction and 2.21 +/- 0.38 ml O2 100 g-1 min-1 130 min after induction. In Group 2 the etomidate infusion was increased from 30 to 60 micrograms kg-1 min-1 after the first study and a significant fall in CMRO2 from 2.52 +/- 0.56 to 1.76 +/- 0.40 ml O2 100 g-1 min-1 was found. Simultaneously, a significant fall in CBF was observed. The CO2 reactivity was preserved during anaesthesia.

Postoperative respiratory complications in non-idiopathic scoliosis.

Abstract: The medical records of 303 patients undergoing fusions for scoliosis correction were retrospectively reviewed. The frequency and type of postoperative respiratory complications were compared in idiopathic versus non-idiopathic scoliosis patients in relation to age, type of spinal fusion procedure, pulmonary function test (PFT) results and preoperative diagnoses. The following factors were found to increase the incidence of problems in the postoperative period: a non-idiopathic type of scoliosis, mental retardation, anterior spinal fusion procedures, age of 20 or more years, a relative arterial hypoxemia and an obstructive component to the PFT's. Topics for further investigation are suggested.