Postoperative analgesia with “3-in-1” femoral nerve block after prosthetic hip surgery

Purpose

To evaluate the efficacy of a single shot “3-in-1” femoral nerve block for prosthetic hip surgery in association with general anaesthesia on post-operative analgesia.

Methods

Forty patients, ASA 1 to 3, received sham block or “3-in-1” femoral nerve block, following Winnie’s landmarks with a nerve stimulator, and 40 ml bupivacaine 0.5% with epinephrine were injected after induction of anaesthesia. Vecuronium, 0.1 mg· kg^?1, was added after performing the block and anaesthesia was maintained with isoflurane, oxygen 40% and nitrous oxide 60%. Fentanyl, 1.5 μg· kg^?1, was administered before incision to all patients. Heart rate, blood pressure, fentanyl requirements and F_ETiso were measured throughout surgery. During the post-operative period, 75 mg diclofenacim and/or 0.1 mg· kg^?1 morphine sc were administered when pain score was > 3/10 and repeated when necessary. Pain scores at first analgesic intervention, at 24 hr and 48 hr as well as diclofenac and morphine requirements after surgery were recorded.

Results

There was no difference in anaesthetic requirements during surgery. The time from performance of sham or “3-in-1” femoral nerve block to the first analgesic intervention (261 ± 49 min versus 492 ± 40 min,P < 0.05) and time from extubation to the first analgesic intervention (61 ± 44 minvs 298 ± 39 min,P < 0.05) were prolonged in the study group. However, pain scores and the analgesic requirements in the postoperative periods (24 and 48 hr) were similar.

Conclusion

There is a short-term benefit during the first few postoperative hours in using a single shot “3-in-1” femoral nerve block to complement general anaesthesia for elective hip surgery.     

Interleukin-10 and Interleukin-1 receptor antagonists increase during cardiac surgery

Background

It has been reported that inflammatory cytokines such as interleukin-8 and 6 (IL-8, IL-6) increase during cardiac surgery and cause postoperative cardiac dysfunction. Therefore, it is important to investigate changes of suppressive cytokines such as IL-10, interleukin-4 (IL-4) and interleukin-1 receptor antagonist (IL-1 ra) dunng cardiac surgery.

Method

Serum levels of cytokines and IL-1 ra were measured in 10 patients during cardiac surgery with cardiopulmonary bypass. Six blood samples were drawn after inducing anaesthesia. In each sample, serum IL-10, IL-4, IL-8, IL-6 and IL-1 ra were measured by enzyme linked immunosorbent assay.

Results

Serum IL-6 and IL-8 concentration (19.1 ±8.8 pg · ml^?1, and 13.4±5.2 pg · ml^?1, preoperatively) increased to 227.5± 191 pg · ml^?1 and 81.0±56 pg · ml^?1 at 60 min after declamping the aorta (P< 0.01, respectively). Serum IL-10 concentration increased at 60 min after dedamping the aorta compared with the preoperative value (from 1.0±0 pg · ml^?1 to 552.0± 158 pg · ml^?1 P< 0.001]). Similarly, serum IL-1 ra concentration increased from the preoperative value of 1331±896 pg · ml^?1 to 43353±12812 pg · ml^?1 at 60 min after dedamping the aorta (P< 0.00l). Positive correlations were obtained between IL-10 and IL-8. and between IL-10 and IL-6 (γ=0.7, γ=0.8, P< 0.001, respectively).

Conclusion

These findings demonstrate that pro-and anti-inflammatory cytokines increase to maintain their balance during cardiac surgery.     

Neuromuscular blocking effects of rocuronium during desflurane, isoflurane, and sevoflurane anaesthesia

Purpose

To determine the magnitude of the potentiation of rocuronium by desflurane, isoflurane and sevoflurane 1.5 MAC anaesthesia.

Methods

In a prospective, randomised, study in 80 patients, the cumulative dose-effect curves for rocuronium were determined during anaesthesia with desflurane, sevoflurane and isoflurane (with N₂O 70%, 15 min steady state) or total intravenous anaesthesia (TIVA) using propofol/fentanyl. Neuromuscular block was assessed by acceleromyography (TOF-Guard®) after train-of-four (TOF) stimulation of the ulnar nerve (2Hz every 12sec, 200 μsec duration), Rocuronium was administered in increments of 100 μg·kg^?1 until first twitch (T₁) depression > 95%.

Results

Rocuronium led to more pronounced T₁ depression with desflurane or sevoflurane anaesthesia than with TIVA. The ED₅₀ and ED₉₅ were lower during desflurane (95 ± 25 and 190 ± 80 μg·kg^?1) and sevoflurane (120 ±30 and 210 ± 40 μg·kg^?1) than with TIVA (150 ± 40 and 310 ± 90 μg·kg^?1) (P < .01), while the difference was not significant for isoflurane (130 ± 40 and 250 ± 90 μg·kg^?1). Following equi-effective dosing (T₁ > 95%) the duration to 25% T₁ recovery, recovery index (25/75), and TOF_0.70 was: 13.2 ± 1.8, 12.7 ± 3.4, and 26.9 ± 5.7 min during anaesthesia with desflurane; 15.5 ± 5.0, 11.4 ± 3.8, and 31.0 ± 6.0 min with sevoflurane; 13.9 ± 4.7, 10.7 ± 3.3, and 26.3 ± 8.9 min with isoflurane; and 13.9 ± 3.9, 11.3 ± 5.7, and 27.5 ± 8,2 min with TIVA anaesthesia (P: NS).

Conclusion

Interaction of rocuronium and volatile anaesthetics resulted in augmentation of the intensity of neuromuscular block but did not result in significant effects on duration of or recovery from the block.     

40 Hz Auditory steady-state response and EEG spectral edge frequency during sufentanil anaesthesia

Purpose

The auditory steady-state evoked response (ASSR) is an evoked potential which provides a sensitive measure of the effects of general anaesthetics on the brain. We used pharmacokinetic-pharmacodynamic (PK-PD) modelling to compare the effects of sufentanil on the amplitude of the ASSR with its effect on spectral edge frequency (SEF) of the electroencephalogram.

Methods

Nine patients scheduled for elective cardiac surgery participated. Midazolam (70 μg·kg^?1 im) was given 60 min before entering the operating room. Anaesthesia was induced with 5 μg·kg^?1 sufentanil at a rate of 0.83 μg·kg^?1·min^?1. The ASSR, SEF and plasma sufentanil concentrations were measured for 30 min ater induction of anaesthesia before surgery. The half-life between the central and effect site compartments (t_1/2K_eo), the 50% inhibitory concentration (IC₅₀) and the slope factor (gamma) were computed.

Results

The amplitude of the ASSR increased during the first three minutes of infusion of sufentanil by up to 40%. This was followed by a rapid decrease between the fourth and fifth minutes to 16% of baseline. The SEF decreased progressively during the first five minutes of infusion to 18% of baseline. Both measures subsequently showed modest recovery. The parameters gamma, IC₅₀ and t_1/2K_eofor ASSR were (mean ±SD) 6,0 ±3.7, 2.1 ±1,2 ng·ml^?1 and 7.3 ±2.4 min. For SEF the values were 5.9 ±5.2, 1.4 ±0.7 ng·ml^?1 (P < 0.05 compared with ASSR) and 6.8 ±2,4 min.

Conclusion

The sensitivity of ASSR to sufentanil is less than that of the SEF.     

Prolonged mivacurium infusion in young and elderly adults

Purpose

This study was designed to evaluate phanmacodynamically and phamnacokinetically if the cis-cis isomer of mivacurium contributed to neuromuscular block during prolonged infusions lasting more than four hours in young adult and elderly (> 60 yr) patients.

Methods

The mechanomyogramic neuromuscular response of the adductor pollicis was recorded in 32 adults 18–59 yr. and 19 elderly (> 60 yr.) patients dunng N₂O:O₂:opioid anaesthesia. The mivacurium infusion rate was adjusted to maintain single twitch depression at 95 ± 4% of control. Blood samples were taken every 30 min to determine the plasma concentration of cis-cis isomer of mivacurium. At the end of the surgical procedure, patients were allowed to recover spontaneously to at least 25% of control twitch response.

Results

The mean mivacurium infusion requirement to maintain 97 ± 1 (mean ± SD)% depression of the twitch response was 6.0 ± 0.4 μg· kg^?1· min^?1 in young adults, and 4.3 ± 0.3 μg· kg^?1· min^?1 in elderly patients (P < 0.001). The infusion requirement in patients with low plasma cholinesterase activity was the lowest 2.4 ± 1.2 μg· kg^?1· min^?1. Plasma cis-cis isomer concentrations reached peak levels within one-two hours and remained relatively constant throughout the duration of infusion even in patients with tow cholinesterase activity. There was no relationship between duration of infusion, plasma concentrations of cis-cis isomer and the early recovery indices of mivacurium (up to 25%). Neuromuscular transmission recovered adequately with or without antagonism in all patients.

Conclusion

When the mivacurium infusion was titrated to maintain 95 ± 4% twitch depression, the plasma concentration of the cis-cis isomer did not increase during prolonged infusions (four hours) and neuromuscular transmission recovers satisfactorily.     

Continuous oesophageal aortic blood flow echo-Doppler measurement during general anaesthesia in infants

Purpose

Invasive haemodynamic monitoring during general anaesthesia in infants is usually limited to very high risk operations, such as cardiac surgery Nevertheless, different surgical procedures and/or anaesthetic techniques justify additional monitoring for children, as for adults. The aim of this preliminary study was to evaluate the feasibility of using a new echo-Doppler device (Dynemo 3000®) capable of measuring continuous aortic blood flow during general anaesthesia in infants.

Methods

Aortic blood flow (ABF) was measured with a small oesophageal probe designed for newborns and infants. The aortic flowmeter was connected with satellite devices to visualise the haemodynamic profile which included ABE pre-ejection period (PEPi), left ventricular ejection time (LVETi), mean artenal pressure, heart rate, stroke volume and systemic vascular resistance. Twelve infants, aged 8–26 mo, undergoing surgery under general anaesthesia were successively included in the evaluation of this device. Isoflurane (1 % end-expired concentration) was introduced to maintain anaesthesia after induction with halothane, midazolam, fentanyl and atracurium.

Results

Correct positioning of the probe was easily obtained in all cases and the recording quality was excellent, whatever the operative position. Recordings of haemodynamic data showed some myocardial depression from isoflurane: decreased ABF (indexed to body surface area) and lengthened PEP/LVET (2.24 ± 0.53 L · min^?1 · m^?2 and 0.32 ± 0.05 respectively, before introduction of isoflurane and 1.71 ± 0.53 L · min^?1 · m^?2 (P = 0.027) and 0.39 ± 0.06 (P ± 0.007) with isoflurane).

Conclusion

These preliminary results suggest that this continuous ABF echo Doppler device may be valuable for pen anaesthetic monitonng in infants.     

Smoking increases the requirement for rocuronium

Purpose

To compare the potency of rocuronium in non-smokers and smokers during general anaesthesia.

Methods

In a randomized, open clinical study, 40 patients, 17–62 yr of age, were anaesthetized with propofol, alfentanil and nitrous oxide in oxygen. After obtaining individual dose-response curves for rocuronium, bolus doses of rocuronium were given to maintain neuromuscular block at 90–99% for 60 min. Evoked adductor pollicis electromyography (EMG) was used to monitor neuromuscular block.

Results

The ED₉₅ values (± SEM) for rocuronium were 460.5 ± 28.9 and 471.5 ± 22.1 μg·kg^?1 for nonsmokers and smokers, respectively (P:NS). However, doses of rocuronium to maintain 90–99% neuromuscular block (± SEM) were 620.1 ± 46.7 and 747.4 ± 56.0 μg·kg^?1·hr^?1 for non-smokers and smokers, respectively (P = 0.0504).

Conclusion

The results may indicate increased metabolism of rocuronium in smokers rather than increased requirement of rocuronium at the receptor site.     

Pharmacokinetics of doxacurium during normothermic and hypothermic cardiopulmonary bypass surgery

Purpose

To compare the pharmacokinetic behaviour of doxacurium in patients undergoing normothermic or hypothermic cardiopulmonary bypass (CPB) for coronary artery bypass graft surgery.

Methods

Twenty patients in two equal groups were studied. Anaesthesia was induced with sufentanil and midazolam after a standard premedication. Doxacurium was administered at 3 × ED₉₅ (80μ·kg^?1), and anaesthesia was maintained with 0.5 μg·kg^?1 hr^?1 sufentanil, 0.05 mg·kg^?1 midazolam and isoflurane 0.5–1%. Systemic temperature for patients in the normothermic and hypothermic groups was maintained at 33–36C and 26–30C respectively. Timed blood and urine samples were collected and pharmacokinetic parameters were estimated using a non-compartmental approach.

Results

For the normothermic and hypothermie groups, terminal elimination half-life (t_1/2B) was 100.1 ± 28 and 183.8 ± 60 min (P < 0.05) respectively, elimination half-life during the CPB phase (T_1/2 CPB) 114.5 ± 10 and 183.8 ± 60 min (P < 0.05), mean residence time 108.8 ± 25 and 164.8 ± 34 min (P < 0.05) and apparent volume of distribution at steady state 0.20 ± 0.03 and 0.26 ± 0.04 L·kg^?1 (P < 0.05). Compared with the hypothermie group, the normothermic group had a higher rate of renal clearance (1.40 ± 0.4 vs 0.93 ± 0.3 ml·min^?1·kg^?1;P < 0.05) and a higher value for renal clearance as a percentage of the total clearance (76.2 ± 10 vs 58.3 ± 20%).

Conclusion

The elimination rate of doxacurium during normothermic CPB is faster than that in hypothermic CPB.     

Validation of the DeLiT Trial intravenous insulin infusion algorithm for intraoperative glucose control in noncardiac surgery: a randomized controlled trial

Purpose

A safe and effective insulin infusion algorithm that achieves rigorous intraoperative glycemic control in noncardiac surgery has yet to be formally characterized and evaluated. We therefore report the validation of the DeLit Trial insulin infusion algorithm.

Methods

Patients scheduled for major noncardiac surgery were randomized to a target intraoperative blood glucose concentration of 4.4-6.1 mmoL·L^?1 (80-110 mg·dL^?1) intensive group or 10-11.1 mmoL·L^?1 (180-200 mg·dL^?1) conventional group. Glucose was managed with a dynamic intravenous insulin infusion algorithm. We compared the randomized groups on glucose time-weighted average (TWA), proportion of time spent within target, number of severe (< 2.2 mmoL·L^?1 or < 40 mg·dL^?1) or moderate (< 2.8 mmoL·L^?1or < 50 mg·dL^?1) hypoglycemic episodes, and within-patient variability in glucose concentrations expressed as standard deviation from the patient mean.

Results

One hundred eighty-seven patients were assigned to intensive glucose control, and 177 patients were assigned to conventional glucose control. Median (lower quartile value [Q1], upper quartile value [Q3]) of intraoperative TWA for the intensive vs conventional groups was 6 [5.6, 6.7] mmoL·L^?1 vs 7.7 [6.9, 9.2] mmoL·L^?1, respectively; P < 0.001. The intensive group spent 49% (29, 71) of the time within target, substantially more time than the conventional group spent either within the intensive target or within its own target (both P < 0.001). The intensive group had slightly lower within-patient glucose variability than the conventional group (0.9 [0.7, 1.3] mmoL·L^?1 vs 1.3 [0.8, 1.8] mmoL·L^?1, respectively; P < 0.001). Three patients had moderate hypoglycemia (intensive group), but none experienced severe episodes.

Conclusion

Tight intraoperative glucose control in noncardiac surgery can be maintained successfully without serious hypoglycemic episodes. (ClinicalTrials.gov number, NCT00433251).     

Physostigmine increases the dose of propofol required to induce anaesthesia

Purpose

This prospective, randomized, double-blind study was performed to determine the effect of administration of physostigmine on the dose of propofol required to produce loss of consciousness.

Methods

Forty female unpremedicated patients were assigned in a random blind design to receive either 2 mg physostigmine or equal volume of normal salineiv, five minutes before induction of anaesthesia with propofol. All patients received general anaesthesia for breast surgery. Propofol was infused at a constant rate of 200 ml · hr^?1 while patients were breathing oxygen 100% via a face mask. In each patient the dose of propofol required to produce loss of the ability to grasp a 20 ml synnge was recorded as the end-point of loss of consciousness. At this point the protocol was terminated and, after intubation of the trachea, anaesthesia was maintained with a nitrous oxide-isoflurane or sevoflurane mixture in oxygen, increments of an opioid and a muscle relaxant. Doses of anaesthetic drugs and duration of anaesthesia vaned and depended on the type of breast surgery, determined by frozen section.

Results

The mean ± SD dose of propofol required to produce loss of consciousness was 2.4 ± 0.6 mg · kg^?1 and 2.0 ± 0.4 mg · kg^?1 in the physostigmine and in the normal saline groups respectively (P = 0.014).

Conclusion

Physostigmine pretreatment increases the dose of propofol required to produce loss of consciousness.     

Optimal dose of thiamylal in combination with midazolam for induction of anaesthesia

Purpose

The optimal dose range of thiamylal, combined with midazolam, in the induction of anaesthesia was evaluated using haemodynamic variables.

Methods

The 200 patients, aged 30 to 70 yr, were randomly divided into five groups by midazolam dosage. Anaesthesia was induced with midazolam 0.05, 0.075, 0.10, 0.15, or 0.20 mg · kg^?1. Two minutes later, 50 mg thiamylal was administered followed by 25 mg increments until verbal response and eyelash reflex disappeared and blood pressure decreased to a level less than that of preinduction. Tracheal intubation was performed with 0.15 mg · kg^?1 vecuronium. Blood pressure and heart rate were monitored during induction. Optimal induction was defined as a systolic blood pressure one minute after intubation within ±20% of that before induction.

Results

There were 164 patients whose systolic blood pressure were within these criteria. Blood pressure decreased two minutes after induction and 3 to 15 min after intubation in all groups. Heart rate increased one minute after intubation in 0.05 mg · kg^?1, 0.075 mg · kg^?1 and 0.10 mg · kg^?1 midazolam groups. The optimal range of thiamylal was 4.0 ± 1.1 (mean + SD), 3.1 ± 1.2, 2.8 ± 1.1, 2.3 ± 1.2, and 1.7 ± 1.0 mg · kg^?1 in combination with midazolam 0.05, 0.075, 0.10, 0.15, and 0.20 mg · kg^?1, respectively.

Conclusion

The optimal dose range, to maintain haemodynamic stability, for thiamylal induction of anaesthesia in combination with midazolam, 0.05-0.2 mg · kg^?1 was found to range from 4.0 to 1.7 mg · kg^?1.     

Cigarette smoking does not affect thiopentone pharmacodynamic or pharmacokinetic behaviour

Purpose

Smoking affects the pharmacodynamic and pharmacokinetic behaviour of several drugs. In smokers, induction of anaesthesia is often stormy. In this study we have determined whether cigarette smoking affected thiopentone pharmacodynamic or pharmacokinetic behaviour during induction of anaesthesia.

Methods

Fifteen smokers and 15 non-smokers, scheduled for elective surgery, were studied. Heart rate, invasive arterial pressures and middle latency auditory evoked potentials were recorded awake and during thiopentone induction (9 mg·kg^?1 lean body mass), before and after tracheal intubation. Blood was sampled up to 24 hr after induction to measure thiopentone plasma concentrations and to calculate pharmacokinetic parameters.

Results

Anaesthesia was adequate in all patients, although haemodynamic intubation response was not blunted. Latencies or amplitudes of middle latency auditory evoked potentials (MLAEP) did not differ between the groups. The postintubation latencies of Nb waves were 48.9 ± 8.1 msec (mean ± SD) in smokers and 48.1 ± 8.5 msec in nonsmokers. Pharmacokinetic data showed no differences between smokers and non-smokers. Clearance of thiopentone was 2.9 ± 1.1 ml·min^?1 ·kg^?1 in smokers and 3.3 ± 1.0 ml·min^?1 ·kg^?1 in non-smokers and elimination half life of thiopentone was 12.5 ± 6.3 hr in smokers and 10.7 ± 3.1 hr in non-smokers, respectively. The haemodynamic response after the induction dose of thiopentone and after tracheal intubation were similar in smokers and non-smokers. Mean postintubation systolic arterial pressures were 192 ± 35 vs 189 ± 20 mmHg and mean postintubation heart rates were 103 ± 12 vs 102 ± 17 beat per minute (bpm) in smokers and non-smokers, respectively.

Conclusion

We conclude, that cigarette smoking does not affect the pharmacodynamic or pharmacokinetic behaviour of thiopentone.     

Densities of cerebrospinal fluid and spinal anaesthetic solutions in surgical patients at body temperature

Purpose

To determine the densities of cerebrospinal fluid (CSF) in patients for surgery under spinal anaesthesia. The densities of the CSF were compared with the densities of local anaesthestic solutions and their mixtures with commonly used spinal opioids.

Method

One ml of CSF was collected from 131 consecutive patients that consented to the study at the time of spinal anaesthesia. Densities were measured at 37°C in a Density Meter that displayed density to the fourth decimal point and was accurate to 0.00003 g·ml^?1 The densities of a selection of spinal anaesthetic drugs were also measured.

Results

The mean CSF density in the study population was 1.00059 ± SD 0.00020. In men of all ages, the mean CSF density was 1.00067 ± 0.0001 8 g·ml^?1; in postmenopausal women 1.00060 ± 0.00015 g·ml^?1; in premenopausal non-pregnant women 1.00047 ± 0.00076 g·ml^?1; and in pregnant women 1.00033 ± 0.00010 g·ml^?1 There were differences between the CSF densities in pregnant women compared with men (P = 0.0001), postmenopausal women (P = 0.0001) and non-pregnant premenopausal women (P = 0.03). Local anaesthetic solutions that contain sugar (glucose or dextrose) were all hyperbaric. In the absence of sugar, all local anaesthetic solutions were hypobaric except for lidocaine CO₂ which was slightly hyperbaric. Opioids were all hypobaric except meperidine which was hyperbaric.

Conclusion

Pregnant women have slightly lower CSF densities than do men and postmenopausal women, and non-pregnant premanopausal women. In the absence of sugar all spinal anaesthetic solutions measured were hypobaric except for lidocaine CO₂ and meperidine, both of which were hyperbaric.     

Continuous caudal anaesthesia with chloroprocaine as an adjunct to general anaesthesia in neonates

Purpose

The authors prospectively evaluated the use of a continuous caudal epidural infusion of chloroprocaine as an adjunct to genera! anaesthesia during intra-abdominal surgery in neonates.

Clinical features

The technique was used in 25 neonates ranging in age from 1 to 28 days and in weight from 2.2 to 4.9 kg. Following anaesthetic induction and tracheal intubation, an initial bolus dose of chloroprocaine 3% (1 or 1.5 ml · kg^?1) was followed by a continuous infusion of 1 or 1.5 ml · kg^?1 · hr^?1 administered through a caudal epidural catheter. No parenteral opioids were administered. The duration of the surgical procedures varied from one hour five minutes to three hours 15 min. The first three neonates received a bolus dose of 1.0 ml kg^?1 followed by an infusion of 1.0 ml · kg^?1 · hr^?1 chloroprocaine 3%. These three neonates required an additional bolus dose followed by an increase in the infusion to 1.5 ml · kg^?1 · hr^?1 to provide surgical anaesthesia. Adequate intraoperative anaesthesia was achieved in all 25 neonates with an infusion of 1.5 ml · kg^?1· hr^?1 of chloroprocaine 3%. This was evidenced by a lack of haemodynamic response to surgical manipulation. No neonate required more than 0.2% isoflurane or 70% nitrous oxide in oxygen. No episodes of haemodynamic instability (decreased blood pressure/bradycardia) related to the caudal epidural anaesthesia were noted. Twenty-three of 25 of the neonates’ tracheas were extubated immediately (within 10 minutes) following the surgical procedure.

Conclusions

Caudal anaesthesia with a continuous infusion of chloroprocaine can be used as an adjunct to general anaesthesia during abdominal surgery in neonates. Our initial experience suggests that the combined technique may eliminate the need for parenteral opioids and limit the intraoperative requirements for inhalational anaesthetic agents.     

Lower oesophageal sphincter tone increases after induction of anaesthesia in pigs with full stomach

Purpose

The lower oesophageal sphincter (LOS) is the main mechanism that prevents gastro-oesophageal regurgitation during anaesthesia. The aim of this study was to assess the effect on lower oesophageal sphincter pressure (LOSP) of rapid sequence induction in pigs with full stomachs.

Methods

Lower oesophageal sphincter pressure and oesophageal barrier pressure (BrP = LOSP minus gastric pressure) were measured using a water-perfused manometric catheter method in 12 pigs after gastric filling with 500 ml of liquid nutrient mixture. Six pigs were randomly allocated to receive 5 mg · kg^?1 propofol and 3 mg · kg^?1 succinylcholineiv, and six pigs received 8 mg · kg^?1 thiopentone and 3 mg · kg^?1 succinylcholineiv.

Results

After induction, mean LOSP increased during the period with fasciculations from 19 ± 4 mmHg to 28 ± 5 mmHg in the propofol-succinylcholine group and from 23 ± 6 mmHg to 36 ± 7 mmHg in the thiopentone-succinylcholine group. The LOSP remained elevated after the fasciculations. LOSP and BrP were not different between the groups.

Conclusions

Induction of anaesthesia with propofol-succinylcholine or thiopentone-succinylcholine increases LOSP and, consequently, BrP in pigs with a full stomach. This increase begins before fasciculations and remains elevated for the period when intubation would occur.     

Vomiting after strabismus surgery in children: ondansetronvs propofol

Purpose

To compare the antiemetic efficacy and costs associated with two anaesthetic regimens in children undergoing strabismus surgery. One regimen contained halothane, nitrous oxide and ondansetron, while the other contained propofol and nitrous oxide.

Methods

Three hundred children aged 2–14 yr undergoing strabismus surgery were enrolled into this single-blind, randomized, stratified, blocked study with a balanced design. Anaesthesia was induced by inhalation with halothane/N₂O/O₂ (Group O) or with 2.5–3.5 mg·kg¹ propofol + 0.5 mg·kg^?1 lidocaineiv (Group P). Group O patients were administered 0.15 mg·kg^?1 ondansetron (maximum dose 8 mg)iv and all patients received atropine 20 μg·kg^?1 iv immediately after induction of anaesthesia. Anaesthesia was maintained with N₂O and halothane (Group O) or N₂O and propofol (Group P). Patients were followed for 24 hr after their operation primarily to assess the incidence of postoperative vomiting. For each case, the costs of the anaesthetic drugs administered and their associated intravenous administration tubing were determined. Drug costs were those prevailing at the study site at the time of the investigation. Fixed costs, such as the cost of the anaesthetic equipment were not assessed.

Results

Groups were similar with respect to demographic data. The incidence of vomiting in both groups was 11 % while in-hospital and 23% after discharge. Each episode of in-hospital vomiting prolonged discharge by 17 ± 4 min, P < 0.001. Mean cost per case for anaesthetic drugs was less in Group 0. 18 ± 8vs 21 ± 10 CDN$. mean ± SD. P < 0.01.

Conclusion

The two methods of antiemetic prophylaxis were equally effective. Propofol-based anaesthesia was more expensive.     

Preoperative ketorolac increases bleeding after tonsillectomy in children

Purpose

To compare the incidence of vomiting following codeine or ketorolac for tonsillectomy in children.

Methods

We had planned to enrol 240 patients, aged 2–12 yr undergoing elective tonsillectomy into a randomized, single-blind study in University Children’s Hospital. The study was terminated, after 64 patients because interim analysis of the data by a blinded non-study scientist concluded that the patients were at undue risk of excessive perioperative bleeding. After induction of anaesthesia by inhalation with N₂O/halothane or with propofol 2.5?3.5 mg· kg^?1 iv, the children were administered 150 μg· kg^?1 ondansetron and 50 μg · kg^?1 midazolam. Maintenance of anaesthesia was with N₂O and halothane in O₂. Subjects were administered either 1.5 mg · kg^?1 codeine im or 1 mg· kg^?1 ketorolac iv before the commencement of surgery. Intraoperative blood loss was measured with a Baxter Medi-Vac® Universal Critical Measurement Unit. Postoperative management of vomiting and pain was standardized. Vomiting was recorded for 24 hr after anaesthesia. Data were compared with ANOVA, Chi-Square analysis and Fisher Exact Test.

Results

Thirty-five subjects received ketorolac. Demographic data were similar. The incidence of vomiting during the postoperative period was 31% in the codeine-group and 40% in the ketorolac-group. Intraoperative blood losses was 1.3 ± 0.8 ml · kg^?1 after codeine and 2.2 ± 1.9 ml · kg^?1 after ketorolac (mean ± SD) P < 0.05. Five ketorolac-treated patients had bleeding which led to unscheduled admission to hospital, P < 0.05, Exact Test.

Conclusion

Preoperative ketorolac increases perioperative bleeding among children undergoing tonsillectomy without beneficial effects.     

Ulinastatin reduces elevation of cytokines and soluble adhesion molecules during cardiac surgery

Purpose

To investigate whether ulinastatin pretreatment (6000 U · kg^?1 before CPB and before declamping of aorta) influenced the production of cytokines and adhesion molecules in the peripheral circulation.

Methods

This prospective randomized study was performed in 22 patients undergoing cardiac surgery. They were divided into two groups. Patients in Group I were untreated and in Group II treated with ulinastatin. The soluble intercellular adhesion molecule-1 (S-ICAM-1), soluble endothelial leukocyte adhesion molecule-1 (S-ELAM-1), interleukin8 and 6 (IL-8, 6) were measured using ELISA kits.

Results

Serum S-ICAM-1 concentration in Group I increased from the preoperative value of 297 ± 27 ng · kg^?1 to 418 ± 106 ng · kg^?1 at 60 min after declamping of the aorta (P < 0.01) but did not change in Group II. Serum S-ELAM-1 concentration did not change in either group. Serum concentration of IL-8 and IL-6 in Group I (37 ± 44 pg · kg^?1, and 59 ± 59 pg · kg^?1, preoperatively) increased to 169 ± 86 pg · kg^?1 and 436 ± 143 pg · kg^?1 at 60 min after declamping of the aorta (P < 0.001, P < 0.001). The increases were greater than those from 25 ± 6 pg · kg^?1 and 30 ± 26 pg · kg^?1 to 56 ± 36 pg · kg^?1 and 132 ± 78 pg · kg^?1 in Group II (P < 0.001, P < 0.001). The levels of S-ICAM-1 correlated with those of IL-8 (r = 0.5, P < 0.001).

Conclusion

These results suggest that ulinastatin may suppress the increase in IL-8 production and the expression of ICAM-1 during cardiac surgery.     

Surgical stress attenuates reflex heart rate response to hypotension

Purpose

The baroreflex-mediated increase in heart rate (HR) in response to acute reduction of systolic blood pressure (SBP) was studied in order to assess whether the changes in arterial baroreflex sensitivity depend on the intensity of surgical stress, and location of visceral and somatic stimulation during surgery.

Methods

Patients were divided into visceral stimulation groups [upper (n = 30) and lower (n = 30) abdominal surgery] and somatic stimulation groups [upper (n = 25) and lower (n = 25) limbs, and chest wall (n = 25) surgery]. Acute hypotension as a baroreflex depressor test was induced by prostaglandin E₁ (PGE₁) 10 min before surgical incision (control) and during surgical manipulation under isoflurane-N₂O anaesthesia or isoflurane-N₂O-fentanyl anaesthesia. Plasma level of ACTH was measured in an additional 40 patients who underwent upper abdominal surgery.

Results

During upper abdominal surgery, the heart rate baroreflex sensitivity (ΔHR/ΔSBP) was depressed from-0.47 ± 0.05 (control) to -0.01 ± 0.04 (P < 0.05). The reflex heart rate baroreflex sensitivity remained unchanged and was similar among the remaining groups of patients. The concentration of ACTH increased from 12.5 ± 1.0 (control) to 343 ± 78.6 pg·ml^?1 (P < 0.05) with isoflurane-N₂O anaesthesia but did not change with isoflurane-N₂O-fentanyl anaesthesia during upper abdominal surgery.

Conclusion

Upper abdominal surgery is associated with the most stressful stimulation to attenuate heart rate baroreflex sensitivity. Integrity of the baroreflex can be preserved by adding opioids to supplement inhalation anaesthesia.     

Accelerated Gastric Emptying but No Carbohydrate Malabsorption 1 Year After Gastric Bypass Surgery (GBP)

Background

Following gastric bypass surgery (GBP), there is a post-prandial rise of incretin and satiety gut peptides. The mechanisms of enhanced incretin release in response to nutrients after GBP is not elucidated and may be in relation to altered nutrient transit time and/or malabsorption.

Methods

Seven morbidly obese subjects (BMI?=?44.5?±?2.8?kg/m²) were studied before and 1?year after GBP with a d-xylose test. After ingestion of 25?g of d-xylose in 200?mL of non-carbonated water, blood samples were collected at frequent time intervals to determine gastric emptying (time to appearance of d-xylose) and carbohydrate absorption using standard criteria.

Results

One year after GBP, subjects lost 45.0?±?9.7?kg and had a BMI of 27.1?±?4.7?kg/m². Gastric emptying was more rapid after GBP. The mean time to appearance of d-xylose in serum decreased from 18.6?±?6.9?min prior to GBP to 7.9?±?2.7?min after GBP (p?=?0.006). There was no significant difference in absorption before (serum d-xylose concentrations?=?35.6?±?12.6?mg/dL at 60?min and 33.9?±?9.1?mg/dL at 180?min) or 1?year after GBP (serum d-xylose?=?31.5?±?18.1?mg/dL at 60?min and 27.2?±?11.9?mg/dL at 180?min).

Conclusions

These data confirm the acceleration of gastric emptying for liquid and the absence of carbohydrate malabsorption 1?year after GBP. Rapid gastric emptying may play a role in incretin response after GBP and the resulting improved glucose homeostasis.