Showing papers in "Acta Anaesthesiologica Scandinavica in 1989"
TL;DR: Provided local anaesthetic potency data can be extrapolated from the isolated nerve preparation to regional anaesthesia in humans, ropivacaine appears to provide a greater margin of safety than bupvacaine, if inadvertently injected into the venous circulation.
Abstract: Anaesthetically equipotent doses of lidocaine, bupivacaine and a new bupivacaine-like local anaesthetic agent, ropivacaine, were injected into the left anterior descending coronary artery of pentobarbital-anaesthetized pigs. The aim was to study the cardiotoxicity of ropivacaine in relation to the two other drugs. A random, crossover, dose response study design was used. The following doses of the drugs were administered: lidocaine (L): 1,2,4,8 and 16 mg, bupivacaine (B): 0.25, 0.5, 1,2 and 4 mg and ropivacaine (R): 0.33, 0.66 1.33, 2.66 and 5.33 mg. Systemic haemodynamics, left ventricular dP/dT and a 12-lead electrocardiogram were recorded continuously during the study period. The drugs depressed cardiac contractility in relation to their local anaesthetic potency on the isolated nerve-4:3:1 (B:R:L). The prolongation of the ECG QRS-interval was regarded as a measure of electrophysiologic toxicity. Comparable prolongation of the QRS-interval was recorded after 2 mg of bupivacaine, 4.5 mg of ropivacaine and 30 mg of lidocaine. Thus, the electrophysiological toxicity ratio was 15:6.7:1 (B:R:L). Provided local anaesthetic potency data can be extrapolated from the isolated nerve preparation to regional anaesthesia in humans, ropivacaine appears to provide a greater margin of safety than bupivacaine, if inadvertently injected into the venous circulation.
240 citations
TL;DR: The haemodynamic differences between the two groups were small compared to the effects of the laparoscopy procedures, and SI and CI did not reach the pre–insufflation values after return to the horizontal position and CO2–exsufflation.
Abstract: Sixteen women were studied during elective diagnostic laparoscopy with CO2-insufflation to an intraabdominal pressure (IAP) of 2 kPa and Trendelenburg tilt to 30 degrees. They were allocated to either a halothane (Group I) or a balanced (Group II) anaesthesia with relaxation and controlled ventilation. Heart rate (HR), arterial pressure, stroke volume, CO2-elimination, end-tidal CO2 vol.% and total respiratory compliance (TRC) were the parameters measured, and mean arterial pressure (MAP), total peripheral resistance (TPR), stroke index (SI) and cardiac index (CI) were calculated. At maximum haemodynamic strain, SI and CI were on average reduced by 42% in both groups, without significant changes in HR and MAP. TPR increased by 50% in Group I and 100% in Group II. The reduction in SI was related to the changes in TRC. A small increment in CO2-elimination after CO2-insufflation was most pronounced in Group II. SI and CI did not reach the pre-insufflation values after return to the horizontal position and CO2-exsufflation. The haemodynamic differences between the two groups were small compared to the effects of the laparoscopy procedures.
149 citations
TL;DR: The efficacy of lignocaine mixed with prop ofol in reducing pain on injection with propofol was studied in 40 children undergoing elective surgery in a double–blind, randomized comparison with glucose.
Abstract: The efficacy of lignocaine (1%) mixed with propofol in reducing pain on injection with propofol was studied in 40 children undergoing elective surgery in a double-blind, randomized comparison with glucose (5%). The pharmacokinetics of propofol in a single dose of 2.5 mg/kg was also studied in eight children participating in the same study. Lignocaine (1 mg) significantly reduced pain on injection compared to the control group (P less than 0.001). The induction characteristics of propofol were not affected by the lignocaine, and no undesirable interaction was found between the two drugs. The first-stage elimination half-life (t1/2 beta) of propofol in children was shorter (mean 9.3 +/- 3.8 (s.d.) min) than the values found in adults. This pharmacokinetic alteration may have clinical significance following repeated administration or continuous infusion of propofol.
108 citations
TL;DR: A clear–cut interaction exists between spinal noradrenergic and cholinergic systems for antinociception in rats, and several possible mechanisms may be considered, including cholinomimetic effects produced by clonidine, and the presence of muscarinic receptors in the dorsal horn of the spinal cord.
Abstract: Antinociceptive effects have been demonstrated after systemic and spinal administration of the adrenoceptor agonist clonidine and cholinomimetic drugs in animals and human. The present investigation was undertaken in rats to study the possible interactions between spinal noradrenergic and cholinergic mechanisms in modulating the reaction to nociceptive stimuli. Using the tail immersion test, an additive antinociceptive effect was found between intrathecal (IT) clonidine (10 micrograms) and physostigmine (15 micrograms, IT). The effect of clonidine was attenuated by atropine (15 micrograms, IT). Physostigmine (15 micrograms, IT) antinociception, which was of short duration was abolished by atropine (15 micrograms, IT) and attenuated by phentolamine (20 micrograms, IT). Neostigmine (5 micrograms, IT) produced a prolonged antinociceptive response. In animals pretreated with 6-hydroxydopamine IT, leading to a selective depletion of spinal cord noradrenaline, physostigmine (15 micrograms, IT) was ineffective in altering the nociceptive test response. Neither clonidine, nor physostigmine produced changes in latency times in the hot plate test (58 degrees C) in the doses employed. In conclusion, a clear-cut interaction exists between spinal noradrenergic and cholinergic systems for antinociception. To explain the interactions, several possible mechanisms may be considered, including cholinomimetic effects produced by clonidine, and the presence of muscarinic receptors in the dorsal horn of the spinal cord.
107 citations
TL;DR: Right ventricular ejection fraction dysfunction is common during septic shock, is directly related to its severity, and can easily be recognized in patients monitored with a PA catheter.
Abstract: Right ventricular ejection fraction (RVEF) was measured by the thermodilution technique in a series of 127 consecutive critically ill patients monitored with a modified pulmonary artery (PA) catheter equipped with a fast response thermistor. Thermodilution RVEF was significantly lower in septic shock (23.8 +/- 8.2%, 93 measurements) than in sepsis without shock (30.3 +/- 10.1%, 118 measurements) or in the absence of sepsis or cardiopulmonary impairment (32.5 +/- 7.1%, 62 measurements). Both myocardial depression and pulmonary hypertension could account for this impairment of RV function. RVEF decreased from 35.1 +/- 9.8 to 24.2 +/- 10.4% (P less than 0.01) during development of septic shock and increased from 25.0 +/- 7.6 to 29.8 +/- 8.5% (P less than 0.05) during recovery (14 patients). Initial RVEF in septic shock was 27.8 +/- 8.6% in 11 patients who survived but only 20.9 +/- 6.7% (P less than 0.02) in the 23 patients who eventually died. Thus, RV dysfunction is common during septic shock, is directly related to its severity, and can easily be recognized in patients monitored with a PA catheter.
103 citations
TL;DR: The rise in α1–acid glycoprotein (AAG) in plasma rose during the 24–h period, probably increases binding of bupivacaine to plasma proteins, diminishing the risk of systemic toxicity.
Abstract: Continuous interscalene brachial plexus block with a single dose of 0.5% bupivacaine 1.25 mg/kg, continued with an infusion of 0.25% bupivacaine 0.25 mg/kg/h, was performed on 24 patients to provide analgesia during shoulder surgery and in the postoperative period. The drugs for general anaesthesia included glycopyrrolate, thiopentone, vecuronium, enflurane and N2O/O2. All patients had signs of regional analgesia 30 min after the block without haemodynamic problems. The infusion of local anaesthetic was interrupted in six patients because of a failure in catheter function. Of the remaining 18 patients, nine needed no complementary analgesics and nine patients received, on average, 1.6 doses of oxycodone (0.15 mg/kg/dose) during a 24-h period. Displacement of the interscalene catheters could be prevented by a fixation suture to the skin. Two patients noted a metallic taste during the bupivacaine infusion. The most common complaints were numbness of the hand (n = 15) and hoarseness (n = 5). The mean (+/- s.e.mean) plasma concentrations of bupivacaine at 30, 60, 180 min and 24 h were 0.68 +/- 0.06, 0.62 +/- 0.05, 0.52 +/- 0.04 and 0.76 +/- 0.01 micrograms/ml, respectively. During the 24-h period, the alpha 1-acid glycoprotein (AAG) concentration (mean +/- s.e.mean) in plasma rose from 0.41 +/- 0.04 g/l to 0.54 +/- 0.04 g/l (P less than 0.001). The concentration of free bupivacaine was below detectable levels (less than 0.01 micrograms/ml) after the 24-h infusion. The rise in AAG probably increases binding of bupivacaine to plasma proteins, diminishing the risk of systemic toxicity.
95 citations
TL;DR: The results of the study indicate that 1% ethanol is a suitable marker for monitoring irrigant absorption by means of the expired breath test in routine transurethral surgery, at this concentration the sensitivity of the test is adequate for detecting absorption, while the ethanol is less toxic than the irrigant fluid itself.
Abstract: The ethanol concentration in the expired breath (EB–ethanol), the volumetric fluid balance and the serum sodium concentration were measured in the course of 60 transurethral resections of the prostate in which the irrigating fluid was 1.5% glycine + 1% ethanol. Measurement of EB–ethanol indicated absorption of irrigant at a rate of more than 150 ml in 10 min, as measured volumetrically. There was a significant direct linear relationship between EB–ethanol and the cumulative volume of irrigant absorbed (R2 = 0.83); this correlation was stronger when the duration of absorption was taken into account (R2 = 0.90). EB–ethanol was inversely related to the overall change in the serum sodium concentration during the operation (R2 = 0.88). Symptoms that are recognized components of the TUR syndrome developed in 8 of the 13 patients absorbing more than 1 1 of irrigant, while the ethanol exerted no adverse effects. The results of the study indicate that 1% ethanol is a suitable marker for monitoring irrigant absorption by means of the expired breath test in routine transurethral surgery. At this concentration the sensitivity of the test is adequate for detecting absorption, while the ethanol is less toxic than the irrigant fluid itself.
93 citations
TL;DR: It is concluded that small doses of midazolam do not prevent, but may attenuate, FITR and that the appearance of rigidity causes alterations of haemodynamic and respiratory variables during induction.
Abstract: In a double-blind randomised study, we examined if pretreatment with small doses of midazolam, given before anaesthesia induction with fentanyl, influences the occurrence of fentanyl-induced thoracic rigidity (FITR). At the same time, the effect of rigidity on the cardiovascular and respiratory system was assessed. Sixteen patients undergoing coronary artery bypass surgery were divided into two groups. The midazolam group (M) received 0.075 mg/kg midazolam i.v. and the placebo group (P) NaCl 0.9% 3 min before the start of fentanyl induction. During the induction period, FITR was assessed clinically on a 3-point scale. Haemodynamic and respiratory variables were collected before anaesthesia induction, at the end of the fentanyl infusion and 3 min after intubation. The incidence of FITR was high in both groups: 63% in Group M and 75% in Group P (n.s.); however, its severity was less in Group M. The appearance of rigidity affected the cardiovascular and the respiratory system: central venous and pulmonary capillary wedge pressures showed a sharp increase in patients with FITR accompanied by CO2 retention, due to an inability to ventilate these patients adequately. We conclude that small doses of midazolam do not prevent, but may attenuate, FITR and that the appearance of rigidity causes alterations of haemodynamic and respiratory variables during induction.
87 citations
TL;DR: A prospective randomised study of the effect when the patient remained sitting for 2 or 60 min before being put in the supine horizontal position, was evaluated in patients and given a spinal anesthesia with 4 ml 0.5% bupivacaine in 8% glucose (hyperbaric).
Abstract: A prospective randomised study of the effect when the patient remained sitting for 2 (Group-2) or 60 min (Group-60) before being put in the supine horizontal position, was evaluated in 12 patients, aged 39-67 years and given a spinal anesthesia with 4 ml 0.5% bupivacaine in 8% glucose (hyperbaric). The maximal cephalad spread of analgesia was obtained after 12.5 min (median) in Group-2 and 75 min in Group-60 (P less than 0.01). The spread of sensory analgesia went to T-6 (Group-2) and L3 (Group-60) after 60 min (P less than 0.01). After 90 min the spread went to T6.5 in Group-60, the difference being statistically significant (P less than 0.001). Given as median and range the maximum cephalad spread in Group-2 was T6(T3-T10) and in Group-60 T6.5 (T2-T10).
85 citations
TL;DR: The amount of morphine transferred by nursing is, even at the peak concentration of 500 ng/ml milk, small and will hardly cause respiratory depression or drowsiness in the child.
Abstract: Five lactating women who underwent surgery and were treated with morphine epidurally or IV/IM in the postoperative phase were included in the study. The morphine concentrations in plasma and breast milk were determined 0, 15, 30, 45, 60, 90, 120, 240, 360 and 480 min after drug administration by means of a specific radioimmunoassay for morphine. The milk-to-plasma ratio was 2.45 +/- 0.8 (mean +/- s.d.). The amount of morphine transferred by nursing is, even at the peak concentration of 500 ng/ml milk, small and will hardly cause respiratory depression or drowsiness in the child.
72 citations
TL;DR: The duration of postoperative ileus after hysterectomy is shorter when epidural bupivacaine is given for postoperative pain relief than when this is achieved by epidural morphine.
Abstract: A comparison was made of the effects of continuous epidural analgesia with bupivacaine and intermittent epidural morphine on bowel function after abdominal hysterectomy. The duration of postoperative ileus was assessed as the time from the end of operation to the first postoperative passage of flatus and feces. Twenty-two patients were randomly allocated to two equal groups. An "epidural morphine" group received general anesthesia and epidural morphine for postoperative pain relief, and an "epidural bupivacaine" group was given combined general anesthesia and epidural anesthesia with 0.5% bupivacaine intraoperatively and epidural analgesia with 0.25% bupivacaine postoperatively. Epidural morphine or bupivacaine was given for 42 h postoperatively. Pain intensity (visual analog scale) was low in both groups, but lower (P less than 0.05) in the epidural bupivacaine group. The time to first passage of flatus was 22 +/- 16 h in the epidural bupivacaine group and 56 +/- 22 h in the epidural morphine group (P less than 0.001). The time to first postoperative passage of feces was shorter (P less than 0.05) in the former than in the latter 57 +/- 44 h vs 92 +/- 22 h). The patients of the epidural bupivacaine group started intake of oral fluids earlier (P less than 0.01) and to a greater extent (P less than 0.05) than those in the epidural morphine group. It is concluded that the duration of postoperative ileus after hysterectomy is shorter when epidural bupivacaine is given for postoperative pain relief than when this is achieved by epidural morphine.
TL;DR: The results of this study indicate that intravenous short‐acting narcotics like fentanyl or sufentanil should be considered as an alternative premedicant for anxious patients who are scheduled for outpatient surgery.
Abstract: One hundred adult female patients scheduled for outpatient laparoscopic procedures were studied. Each patient received intravenous premedication about 30 min before induction of anaesthesia. The premedications were given in a double-blind random order and were either a placebo, morphine (0.04 mg/kg), meperidine (0.35 mg/kg), fentanyl (0.75 microgram/kg) or sufentanil (0.15 microgram/kg). All patients received a standard anaesthetic regimen. Transient light-headedness was common following narcotic injections. Overall, sufentanil was superior to the placebo and to other narcotics in its ability to reduce preoperative anxiety and to provide more satisfactory induction, maintenance and recovery from anaesthesia. The incidence of postoperative nausea, vomiting and other side effects was not higher and discharge times were not longer after sufentanil compared to the placebo group. Complete recovery as assessed by telephone interview 24-48 h after the operation revealed no difference between the sufentanil and the other groups. The results of this study indicate that intravenous short-acting narcotics like fentanyl or sufentanil should be considered as an alternative premedicant for anxious patients who are scheduled for outpatient surgery.
TL;DR: The influence of indomethacin on the need for postoperative analgesics was investigated in a double‐blind study of 41 patients scheduled for abdominal hysterectomy and seems to offer few advantages compared to a purely postoperative regime and may increase the risk of bleeding complications.
Abstract: The influence of indomethacin on the need for postoperative analgesics was investigated in a double-blind study of 41 patients scheduled for abdominal hysterectomy. The incidence of side effects was evaluated. The patients were randomly allocated to treatment with either indomethacin, 0.8 mg/kg i.v. preoperatively, followed by 100 mg rectally 8-hourly for 3 days (Group I), or placebo (Group P), in both cases supplemented with nicomorphine as needed. Thiopentone was used for induction of anaesthesia, followed by nitrous oxide, enflurane, suxamethonium, and pancuronium. The average nicomorphine requirement during the study was 14.0 mg/24 h lower in Group I than in Group P. The pain score values were slightly lower in Group I when resting, but similar on movement. A significant increase in perioperative blood loss was found in Group I. Beginning the indomethacin treatment with a preoperative i.v. bolus seems to offer few advantages compared to a purely postoperative regime and may increase the risk of bleeding complications.
TL;DR: It is concluded that the faster recovery gives propofol an advantage over thiopental and etomidate in outpatient anesthesia.
Abstract: Propofol, thiopental and etomidate, with 20 patients in each group, were compared for anesthesia of short duration in women undergoing termination of pregnancy, with respect to: 1: pain on injection (equally often after propofol and etomidate, but more rarely after thiopental); 2: apnea following induction (no difference); 3: involuntary muscular movements more frequent after etomidate); 4: blood pressure (larger drop after propofol); 5: heart rate (greater increase after thiopental); 6: time to eye opening on command (longer after propofol); 7: Steward score on eye opening (no difference); 8: coin counting after 15, 30 and 60 min (performance better after propofol at 15 and 30 min, producing even shorter times than preoperatively at 60 min); 9: reaction time after 15, 30 and 60 min (performance better after propofol, producing even shorter times than preoperatively at 60 min. It is concluded that the faster recovery gives propofol an advantage over thiopental and etomidate in outpatient anesthesia.
TL;DR: The findings suggest that besides prompt collapse of lung tissue during induction of anaesthesia, absorption of gas from closed‐off or poorly ventilated regions takes place and further increases the atelectatic area.
Abstract: The development of atelectasis and effects on gas exchange during enflurane anaesthesia in nitrogen/oxygen or nitrous oxide/oxygen (inspired oxygen fraction 0.4) were studied in 16 lung-healthy patients (mean age 49 years). Awake, no subject displayed atelectasis as assessed by computed x-ray tomography of the thorax. Pulmonary gas exchange, studied by multiple inert gas elimination technique, and blood gases were normal. After 10 min of enflurane anaesthesia in nitrogen/oxygen, 14 of 16 subjects had developed atelectasis. After 30 min of enflurane anaesthesia in nitrogen/oxygen or nitrous oxide/oxygen, all patients had developed atelectasis, and a further increase was observed after 90 min of anaesthesia to approximately 5% of the intrathoracic area. There was no difference between the two anaesthesia groups. In the nitrogen group, shunt rose to a maximum of 5.8% at 30 min of enflurane anaesthesia, with a significant reduction to the initial anaesthesia level after 90 min of anaesthesia (3.4%). Perfusion of poorly ventilated lung regions (low VA/Q) averaged 4-5% and did not vary significantly during the anaesthesia. In the nitrous oxide group, shunt increased to 6.3% after 90 min of anaesthesia, and there was a parallel decrease in perfusion of low VA/Q regions. The findings suggest that besides prompt collapse of lung tissue during induction of anaesthesia, absorption of gas from closed-off or poorly ventilated regions takes place and further increases the atelectatic area.
TL;DR: New ventilator strategies are now possible that could not be attempted safely with previous equipment, but whether to use these new ventilators to achieve the lowest possible mean and peak airway pressures, or an optimal alveolar volume is decided.
Abstract: High frequency ventilators (HFV) transport CO2 out of the lung with much smaller pressure and volume cycles than are required during conventional mechanical ventilation (CMV). With HFVs of the active expiration type (i.e. oscillators), the efficiency of this C 0 2 elimination is relatively independent of mean lung volume ( 1 ) . New ventilator strategies are now possible that could not be attempted safely with previous equipment. In particular, we must now decide whether to use these new ventilators to achieve the lowest possible mean and peak airway pressures, or an optimal alveolar volume (Fig. 1) . Both options are possible, but they are mutually exclusive because of the intrinsic pressure-volume characteristics of the lung. Since the earliest days of HFV research, it has been assumed that any likely advantage of these new techniques would arise from their use to support gas exchange at the lowest possible peak and mean intrapulmonary pressure (2, 3). When dealing with established barotrauma, such an approach is both logical and effective (3-5). However one cannot assume that a “low pressure” strategy is also optimal for other kinds of pathophysiology. In the atelectasis-prone lung, evidence is mounting that ongoing atelectasis in itself augments the pathological processes that result in structural lung damage (6-10).
TL;DR: It is concluded that the outcome of intensive care can be evaluated by studying only the survival, since the survival rate is correlated to changes in health status among survivors in the different admission groups.
Abstract: In order to evaluate intensive care, all adult patients (980) admitted to a multidisciplinary intensive care unit (ICU) during 1 year were followed prospectively. The ICU mortality was 9,6%. One year after admission the survival was 73.6%. By that time the surviving patients had a further survival that was 96% of that of the general population. Of the 1–year survivors, 22.3% had deteriorated in health status compared to 3 months before the stay in ICU. In the admission groups with high mortality the survivors had a more pronounced deterioration in health status. Increased age and length of stay in the ICU were associated with higher mortality but not with changes in health status. We conclude that the outcome of intensive care can be evaluated by studying only the survival, since the survival rate is correlated to changes in health status among survivors in the different admission groups. One year after admission most of the surviving patients had regained their previous health status and their further survival was almost the same as that of the general population.
TL;DR: The results of a single, large–volume injection of bupivacaine 0.5% in the thoracic paravertebral space are presented, achieving pain relief over several Thoracic dermatomes in patients with respiratory compromise secondary toThoracic or upper abdominal injury.
Abstract: The adverse effects of pain on acutely ill or traumatized patients are well documented. A variety of pain-relieving techniques are now available to meet the varied requirements for pain relief. This paper presents the results of a single, large-volume injection of bupivacaine 0.5% in the thoracic paravertebral space, achieving pain relief over several thoracic dermatomes in patients with respiratory compromise secondary to thoracic or upper abdominal injury. The block proved quick and simple to perform, with excellent clinical results of long duration and virtually no complications. Although not previously described, this single, large-volume injection approach to achieving an extensive thoracic paravertebral block may well become an important pain management technique in appropriate patients.
TL;DR: The current therapeutic modalities available to reduce the incidence of postoperative respiratory failure, as well as related morbidity and mortality are analyzed.
Abstract: This review covers the physiological and clinical implications of lung function during anesthesia and respiratory insufficiency in the postoperative period. We have divided it into 3 main sections: 1) lung function changes induced by anesthesia and surgery, in which the impact on pulmonary mechanics, ventilation/perfusion changes and gas exchange are examined; 2) physiological implications of postoperative respiratory function secondary to decreased alveolar ventilation, development of atelectasis, and interstitial lung edema; and 3) clinical implications of postoperative respiratory failure. In this last section we analyze the current therapeutic modalities available to reduce the incidence of postoperative respiratory failure, as well as related morbidity and mortality.
TL;DR: The most relevant finding was that AT III was equally depressed immediately after surgery in all groups, but returned to normal significantly faster in the epidural group, which could be one of the mechanisms responsible for the beneficial effect of this technique on the prevention of thromboembolic complications.
Abstract: Eighty patients undergoing total hip replacement (THR) were randomly allocated to three groups. Group I (n = 29) received general anaesthesia, Group II (n = 29) epidural anaesthesia and Group III (n = 22) the same epidural as Group II and the same general anaesthesia as Group I but with a lower isoflurane concentration. Prothrombin time (PT), activated thromboplastin time (APTT), fibrinogen (FG), plasminogen (PG), antithrombin III (AT III), protein C (Proc C), alpha-2-antiplasmin (alpha 2AP), Factor VIII coagulating activity (F VIII:C), von Willebrand factor antigen (vWF:Ag), von Willebrand ristocetin cofactor (vWF:Rcof), tissue plasminogen activator (tPA) as antigen and activity were measured before induction (A), at the end of surgery (B), on the first postoperative morning (C) and 7 days postoperatively (D). The most relevant finding was that AT III was equally depressed immediately after surgery in all groups, but returned to normal significantly faster in the epidural group (mean values at C: 96.2% in Group I, 104.1% in Group II, 92.7% in Group III). The faster return to normal of AT III after epidural anaesthesia could be one of the mechanisms responsible for the beneficial effect of this technique on the prevention of thromboembolic complications.
TL;DR: The continuous paravertebral bupivacaine infusion used here was insufficient as the only analgesic after cholecystectomy, in contrast, epidural blockade with combined bupvacaine and low dose morphine produced total pain relief in six of ten patients.
Abstract: Twenty patients undergoing elective cholecystectomy via a subcostal incision were randomized in a double-blind study to either thoracic paravertebral blockade with bupivacaine 0.5% (15 ml followed by 5 ml/h) or thoracic epidural blockade with bupivacaine 7 ml 0.5% + morphine 2 mg followed by 5 ml/h + 0.2 mg/h, respectively for 8 h postoperatively. Mean initial spread of sensory analgesia on the right side was the same (Th3,4-Th11 versus Th2,6-Th11), but decreased (P less than 0.05) postoperatively in the paravertebral group. All patients in the epidural group had bilateral blockade, compared with three patients in the paravertebral group. In both groups only minor insignificant changes in blood pressure and pulse rate were seen postoperatively. Pain scores were significantly higher in the paravertebral group, as was the need for systemic morphine (P less than 0.05). Pulmonary function estimated by forced vital capacity, forced expiratory volume and peak expiratory flow rate decreased about 50% postoperatively in both groups. In conclusion, the continuous paravertebral bupivacaine infusion used here was insufficient as the only analgesic after cholecystectomy. In contrast, epidural blockade with combined bupivacaine and low dose morphine produced total pain relief in six of ten patients.
TL;DR: The RRA method proved to be quite useful in evaluating the kinetics of glycopyrrolate and its relationship to various clinical effects, indicating that the oral route of drug administration is of no value as a routine premedication.
Abstract: In the present study, a sensitive and reproducible radioreceptor assay (RRA) was used to evaluate the basic pharmacokinetic properties of glycopyrrolate, a quaternary amine with peripheral antimuscarinic activity. Based on the plasma levels after a single intravenous injection, 6 micrograms/kg (n = 6), the distribution phase half-life (2.22 +/- 1.26 s.d. min) and the elimination phase half-life (0.83 +/- 0.29 h) of glycopyrrolate were short due to the low distribution volume during the elimination phase (0.64 +/- 0.29 l/kg) and to the respectively high total plasma clearance value (0.54 +/- 0.14 l/kg/h). An intramuscular injection, 8 micrograms/kg (n = 6), was followed by a fast and predictable systemic drug absorption and clinical effects (heart rate increase, dry mouth). In this group the time to maximum plasma concentration (tmax) was 27.48 +/- 6.12 min and the maximum plasma concentration (Cmax) was 3.47 +/- 1.48 micrograms/l. After oral drug intake, 4 mg (n = 6), an apparently low and variable gastrointestinal absorption was found (tmax = 300.0 +/- 197.2 min, Cmax = 0.76 +/- 0.35 microgram/l), thus indicating that the oral route of drug administration is of no value as a routine premedication. The correlation between the plasma concentration of glycopyrrolate and the drug effects appears to be variable. Because of its sensitivity, the RRA method proved to be quite useful in evaluating the kinetics of glycopyrrolate and its relationship to various clinical effects.
TL;DR: The response to halothane and caffeine exposure of skeletal muscle from NMS and control subjects was the same and significantly different from that of muscle from patients susceptible to MH.
Abstract: The neuroleptic malignant syndrome (NMS) is an uncommon but dangerous complication of treatment with neuroleptic drugs. A primary defect in skeletal muscle has been suggested in view of similarities in the clinical presentations of NMS and anaesthetic-induced malignant hyperthermia (MH). The in vitro halothane-caffeine contracture tests are the most reliable method of identifying individuals susceptible to MH. The aim of this study was to define if a relationship exists between NMS and MH susceptibility. Hence, the in vitro halothane and caffeine contracture tests were performed on muscle tissue obtained from eight NMS, ten MH-susceptible and ten control patients. The results, which are expressed in accordance with the criteria of the European MH Group, defined the eight NMS subjects as MH non-susceptible. The response to halothane and caffeine exposure of skeletal muscle from NMS and control subjects was the same and significantly different from that of muscle from patients susceptible to MH. Furthermore, muscle from subjects in NMS and control group responded similarly to increasing concentrations of chlorpromazine. These results do not point towards an association between NMS and MH.
TL;DR: No correlations were found between sedation or fear and the level of any of the hormones or metabolites in patients undergoing orthopaedic surgery under spinal anaesthesia or before the spinal block.
Abstract: Forty–two healthy male patients (aged 19–40 years), undergoing orthopaedic surgery under spinal anaesthesia (3 ml isobaric 0.5% bupivacaine), were given clonidine 4.5 μg kg–1 orally either 2 (Group I, n= 10) or 4 (Group II, n=10) hours before the operation, diazepam 0.15 mg kg–1 orally (Group III, n=10) or a placebo tablet (Group IV, n= 12) 2 h before the operation. Plasma concentrations of Cortisol, noradrenaline (NA), adrenaline (A), 3,4–dihydroxyphenylglycol (DHPG) and dihydroxyphenylacetic acid (DOPAC) were assayed from venous blood samples just before premedication and just before the spinal block. Cerebrospinal fluid (CSF) concentrations of Cortisol, tryptophan, 5–hydroxyindoleacetic acid and catecholamine metabolites were assayed from a sample taken before the spinal block. The plasma NA concentrations of the patients in the groups receiving clonidine decreased clearly compared with the other groups (P < 0.05). The NA metabolite DHPG was also lower in Groups I and II than in Group III (P < 0.05) after premedication. Plasma A concentrations were lower in Groups I and III than in Group IV (P < 0.05). The CSF concentrations of the different substances were similar in all groups. In Group I the sensory blockade lasted significantly longer than in Group III (P<0.05) and the mean duration of motor blockade was longer in Group I than in Groups III and IV (P < 0.05). Two patients in both clonidine groups developed bradycardia (heart rate <45 min–1) requiring atropine treatment. The mean lowest heart rate was lower in Group I than in Groups III and IV (P < 0.05). The patients in Group II were more sedated than those in Group IV (P < 0.05), but the degree of fear was similar in all groups. No correlations were found between sedation or fear and the level of any of the hormones or metabolites.
TL;DR: This group of patients experienced an extremely high cardiac mortality over the first 6 months following resuscitation, and adjustment of these and other covariates increased the significance of difference between ECG groups.
Abstract: In a prospective multi-center study, 262 patients were given general intensive care therapy following cardiopulmonary resuscitation if they were still comatose and unresponsive to pain 10 min after restored spontaneous circulation. Mortality (mainly cardiac) was 53.4% over the first 10 days, and 49% of the remaining survivors died between 10 days and 6 months. In the subsequent 6 months few patients died. Presenting electrocardiograms (ECG) showed ventricular fibrillation (VF) in 54.2%, asystole in 29.8% and electromechanical dissociation (EMD) in 9.2% of the patients. One-year survival, 14.1% for asystole, 4.2% for EMD and 26.0% for VF and VT (ventricular tachycardia), differed significantly (P less than 0.01). VF/VT patients were older and had more cardiovascular disease. Adjustments of these and other covariates increased the significance of difference between ECG groups. Successful resuscitations from asystole or EMD appeared to be more common than has previously been reported, but this group of patients experienced an extremely high cardiac mortality over the first 6 months following resuscitation.
TL;DR: The results underscore the significance of capnometry for rapid detection of inadvertent oesophageal intubation and remind us that high–resolution pulse oximetry is a valuable supplement but not a substitute for capNometry.
Abstract: The aim of our retrospective study was to evaluate the efficacy of routine pulse oximetry and capnometry for detection of oesophageal tube misplacement. Patients undergoing ENT interventions at our hospital are routinely monitored by ECG, arterial blood pressure by cuff, capnography, and pulse oximetry. Beat-to-beat values of Sao2 and CO2 waveform were recorded by a graphic printer connected to a microcomputer, ASA I patients were routinely preventilated with FIO2 = 0.3, and ASA II-III patients with FIO2 = 1.0. Anaesthesia was performed by junior anaesthesiologists under the close supervision of a resident. During a 16-month period, 1372 patients were anaesthetized. The records of 21 patients with accidental oesophageal tube misplacement were available for retrospective evaluation. Nine patients were preventilated with FIO2 = 0.3 (ASA I), 12 patients with FIO2 = 1.0 (ASA II-III). Rapid detection of oesophageal tube position as early as the first ventilation is possible by capnometry, because of the highly significant difference in end-tidal CO2 (0.2 +/- 0.2 vol%; tracheal intubation: 3.7 +/- 0.9 vol.%; P less than 0.0001). The present advanced pulse oximetry method does not permit differentiation between oesophageal and tracheal tube position within 30 s in patients preventilated with FIO2 = 1.0. Oesophageal misplacement was detectable within 7.5 +/- 0.9 s in patients preventilated with FIO2 = 0.3 due to a 2.1 +/- 0.8% decrease in Sao2 (P less than 0.001). Our results underscore the significance of capnometry for rapid detection of inadvertent oesophageal intubation. High-resolution pulse oximetry is a valuable supplement but not a substitute for capnometry.
TL;DR: Clinically, there was some pain relief after the intrapleural bupivacaine, and the VAS and PQ scores 30 min after bupvacaine instillations diminished to an extent similar to that after oxycodone treatment, while the need for analgesics during the day of operation was less in the bupavacaine group than in the control group (P < 0.001).
Abstract: The effect of intrapleural bupivacaine in the treatment of post-thoracotomy pain was evaluated. Bupivacaine, 0.5% 20 ml, with adrenaline (5 micrograms/ml) was given through an indwelling intrapleural catheter, at 4-h intervals four times daily for 2 days. No pleural suction was applied during and 10 min after each injection. A control group received intramuscular oxycodone on request. A visual analogue scale (VAS), a pain questionnaire (PQ) and registration of the need for supplementary analgesics were used for the assessment of postoperative analgesia. Blood-gas analyses showed elevated PaCO2 values in both groups on the day of operation and on the first postoperative day, without differences between the groups. Plasma concentrations of bupivacaine did not reach toxic values, and no symptoms of central nervous toxicity or any other untoward reactions were found during the study period. Clinically, there was some pain relief after the intrapleural bupivacaine. The VAS and PQ scores 30 min after bupivacaine instillations diminished to an extent similar to that after oxycodone treatment. The need for analgesics during the day of operation was less in the bupivacaine group than in the control group (P less than 0.001). The number of oxycodone supplementation doses during 48 h postoperatively was, however, not smaller in the bupivacaine group than in the control group.
TL;DR: It is concluded that intravenous verapamil is effective in reducing pressor responses during endotracheal intubation, especially in hypertensive patients.
Abstract: This study was undertaken in surgical patients in order to evaluate the effects of intravenous verapamil on the circulatory responses to laryngoscopy and tracheal intubation. Laryngoscopy for tracheal intubation was initiated 1 min after thiamylal 5 mg.kg-1 and succinylcholine 1.5 mg.kg-1 in the control group (n = 21). The verapamil group (n = 23) received intravenous verapamil 0.1 mg.kg-1 immediately after thiamylal-succinylcholine administration. The resulting changes in mean arterial pressure (MAP) and heart rate (HR) were continuously measured. Compared with the control group, MAP increased less in response to laryngoscopy and tracheal intubation (56 +/- 13% versus 25 +/- 15% above baselines, P less than 0.01) and returned toward baseline sooner in patients receiving verapamil. For hypertensive patients, MAP increases from baseline after intubation were 18 +/- 9% in the verapamil group, and 53 +/- 14% in the control group, respectively (P less than 0.001). Increases in HR response to laryngoscopy for intubation were comparable in both groups. We conclude that intravenous verapamil is effective in reducing pressor responses during endotracheal intubation, especially in hypertensive patients.
TL;DR: Infiltration of local anesthetic with epinephrine can thus safely protect against potentially dangerous increases in arterial pressure when the Mayfield holder is used.
Abstract: A marked hypertensive response is often seen when the Mayfield skull-pin device is applied to stabilize the head of the anesthetized patient for neurosurgery. In a prospective, blinded and randomized trial, 10 patients received an infiltration block of 0.5% mepivacaine with epinephrine 5 micrograms/ml (3 ml at each pin site) 1 min before the Mayfield holder was applied. Ten patients received normal saline and served as controls. All patients were under general anesthesia induced with sodium pentothal, fentanyl and pancuronium, and maintained with isoflurane in nitrous oxide/oxygen and increments of fentanyl. In the control group, there were significant increases in mean arterial pressure (mean increase 43%, P less than 0.001) and heart rate (15%, P less than 0.01) at 0.5, 1 and 2 min after application. In the mepivacaine group, no significant changes occurred. Infiltration of local anesthetic with epinephrine can thus safely protect against potentially dangerous increases in arterial pressure when the Mayfield holder is used.
TL;DR: Early use of HFOV at a high Paw favorably alters the course of HMD, and this strategy results in lung overinflation which may adversely affect venous return and cardiac output.
Abstract: To assess the efficacy of high frequency oscillatory ventilation (HFOV) in the management of infants with hyaline membrane disease (HMD), we compared two HFOV strategies with conventional positive pressure ventilation with positive end expiratory pressure (PPV) for 24 h in premature baboons (140 d gestation). Three out of 14 PPV, five out of five HFOV-E (begun at birth; 15 Hz; I:E 1:2), and none of 10 HFOV-L (begun after 3 h PPV; 10 Hz; I:E 1:2) were killed at 24 h for morphologic examination. Physiologic (Paw, Pa/AO2, IO2, B.P., pulse, blood gases) data on all animals in each group were assessed at each 3 h interval and over time. Intergroup differences in radiographs at 0 and 24 h and in morphology were quantitatively assessed by comparison with a panel of standards. All animals had radiographic HMD. Initial Paw was set higher with HFOV-E (16.8) than PPV or HFOV-L (14.1, 14.1). PPV baboons required increasing Paw to maintain constant Pa/AO2. Six out of 14 PPV animals developed airleak and three out of three had morphologic HMD. In contrast Pa/AO2 was higher in both HFOV groups at lower Paw by 24 h. None of 15 HFOV animals developed airleak. HFOV-E lungs had dramatic differences in morphology with uniform saccular opening and decreased edema and hyaline membranes compared to PPV. HFOV-L had less dramatic effects because of lower Paw and delayed application. Early use of HFOV at a high Paw favorably alters the course of HMD. Unless closely monitored, this strategy results in lung overinflation which may adversely affect venous return and cardiac output.