bluuebunny/crossref_metadata_2025 huggingface dataset:
Intestinal and hepatic perfusion and metabolism in hypodynamic endotoxic shock. Effects of nitric oxide synthase inhibition
Authors: Dahm P. L. , Thörne J. , Myhre E. , Grins E. , Mårtensson L. , Blomquist S.
Published: March 2003

Background: Inhibition of nitric oxide synthase (NOS) has been claimed to be beneficial in septic shock. We investigated the overall and regional effects of a NOS‐inhibitor on perfusion and metabolism during severe endotoxic shock.

Methods: Nineteen anaesthetised pigs were catheterised and ultrasonic flow‐probes were placed around the portal vein, the hepatic artery, and the superior mesenteric artery. Thirteen animals were given a 3‐h infusion of endotoxin; in 6 of these an infusion of NG‐nitro‐L‐arginine‐methyl‐ester (L‐NAME) was started an hour after the start of endotoxin while 7 animals served as controls and received endotoxin only. Six animals were sham operated with no further intervention.

Results: Endotoxin produced a hypodynamic shock with pulmonary hypertension. L‐NAME did not increase arterial blood pressure, but deepened the fall in cardiac output and enhanced the increase in systemic and pulmonary vascular resistance. The infusion of endotoxin caused a decrease in flows in all regions. The addition of L‐NAME induced a further decrease in the mesenteric artery flow only. L‐NAME had no additional effect on hepatic artery flow ratio, while a transient decrease was seen in mesenteric flow ratio. Portal flow ratio decreased in the control group only. Global as well as regional oxygen extraction increased in both groups, more so in the L‐NAME group. Lactate levels increased with no differences between the groups.

Conclusion: In hypodynamic endotoxic shock, L‐NAME infusion enhanced pulmonary vasoconstriction and increased left ventricular afterload. The resulting hypoperfusion caused an increase in mortality. The effects of L‐NAME on global and mesenteric blood flow and metabolism were similar, while L‐NAME had no additional effects on hepatic hypoperfusion or oxygen extraction. Thus, nitric oxide does not seem to be a major factor in the preservation of hepatic perfusion during unresuscitated endotoxic shock.
Segmental pulmonary vascular responses to changes in pH in rat lungs: role of nitric oxide
Authors: Gao Y. , Tassiopoulos A. K. , Mcgraw D. J. , Hauser M. C. , Camporesi E. M. , Hakim T. S.
Published: March 2003

Background: Respiratory or renal failure is associated with changes in blood pH. Changes in pH may have profound effects on vascular tone and reactivity. Site of action of acidosis in the pulmonary vasculature and the role of nitric oxide production remain unclear.

Methods: We utilized isolated rat lung preparation perfused with autologous blood (Hct=20%, flow rate=33 ml/min), and investigated the effect of acidosis and alkalosis (induced by ventilation with high and low inspired CO2) on vascular resistance and the role of nitric oxide during resting and elevated tone conditions. Changes in resistance were described in terms of small and large arteries and veins, using the vascular occlusion technique.

Results: Acidosis (PCO2=66.7±0.7 mmHg, pH=7.17±0.01, PO2=255±3 mmHg) caused vasoconstriction under resting and increased vascular tone conditions (U46619‐induced). The changes in resistance occurred primarily in the small arteries. In contrast, alkalosis (PCO2=20.1±0.3 mmHg, pH=7.61±0.01, PO2=244±3 mmHg) caused vasodilation only at elevated tone conditions. Nitrow‐L‐arginine (LNA), an inhibitor of nitric oxide synthase, increased vascular resistance slightly but did not modulate the responses to pH, suggesting that such responses are not nitric oxide dependent. During KCl‐induced contraction, the effects of pH were abolished.

Conclusions: We conclude that in rat lung, acidosis causes an increase in pulmonary vascular resistance at normal and elevated tone conditions. Furthermore, the response is limited primarily to the small arteries, and is not mediated by nitric oxide. Alkalosis tends to cause the opposite effects. The effects of acidosis and alkalosis were abolished when vascular tone was elevated with a low dose of KCl, suggesting that vascular response to pH may involve changes in membrane potential.
The direct effect of halothane on myocardial contraction in rat myocytes with poorly developed gap junctional intercellular communication
Authors: Kanaya N. , Kimura H. , Nakayama M. , Tsuchida H. , Ohshika H. , Namiki A.
Published: March 2003

Background: The gap junction channel plays an important role in synchronous beating in the heart, and the reduction in the amount of gap junctional intercellular communication (GJIC) is thought to be the main arrhythmogenic factor in diseased heart. However, the effect of halothane on myocardial contraction in heart tissue with less GJIC is not well known. The purpose of the present study is to examine the direct effect of halothane on myocardium with poorly expressed GJIC.

Methods: Ventricular myocytes were obtained from neonatal rats by enzymatic digestion with collagenase and then cultured for 3 or 7 d. We have previously reported that the number of gap junctions at 3 d is approximately 10% of that at 7 d (1). The myocytes were stabilized in serum‐free medium, and the spontaneous beating rate and amplitude were measured by a fiberoptic sensor.

Results: Heptanol (2 mM), an inhibitor of GJIC, abolished synchronized beating in myocytes cultured for 7 d. Halothane decreased the beating rate and amplitude in both groups of myocytes in a concentration‐dependent manner (P<0.05). Halothane at 1 and 2 MAC (adult rat MAC) decreased the beating rate more in myocytes cultured for 3 d than in myocytes cultured for 7 d (P<0.05). Halothane reduced beating amplitude equally in both groups. Asynchronous contraction developed more frequently among myocytes cultured for 3 d than for those at 7 d.

Conclusion: Halothane may block the GJIC channels, and when the number of these channels is reduced, exposure to halothane may cause asynchronous beating and decrease the beating rate. However, the halothane‐induced decrease in amplitude is probably not due to blockade of GJIC because reducing the number of GJIC channels did not alter halothane’s depressant effect.
Perioperative ST‐segment depression and troponin T release
Authors: Rapp H.‐J. , Rabethge S. , Luiz T. , Haux P.
Published: March 2003

Background: Patients undergoing major vascular surgery are at constant risk of developing perioperative myocardial complications, especially myocardial infarction. The following study was performed to answer the question whether ST segment changes, analysed by Holter monitoring and ST segment analysis, are accompanied by release of cardiac troponin T, a highly specific marker of myocardial damage.

Methods: Tventy patients undergoing elective aortic resection were studied by performing Holter ECG, including ST segment analysis, beginning on the evening before surgery until the third postoperative day. Within this period serum levels of cardiac troponin T were determined at 8 timepoints.

Results: A total of 8/20 of the patients (40%) showed significant ST depressions (range −0.17/−0.68 mV), without any clinical symptom, with a median of 9 episodes (range 2–24). In 3 of the 8 patients, each with repetitive periods of ST depression, elevated troponin T levels were found (0.45/0.52/1.69 μg/l). No troponin T release nor cardiac events were noticed in the remaining patients. No dependancy could be found between troponin T release and the magnitude of ST depression or the number of ST depression episodes.

Conclusion: Haemodynamic changes, oxygen imbalance and stress during major vascular surgery frequently lead to an ischaemic burden, which is indicated by ST segment changes during ECG ST analysis. Longlasting ST depression reaching an individual critical cut‐off limit followed by structural myocardial damage may be verified by elevated levels of cardiac troponin T. Prolonged periods of ST depression should be followed by determination of cardiac troponin T.
Neuroprotective properties of propofol and midazolam, but not pentobarbital, on neuronal damage induced by forebrain ischemia, based on the GABAA receptors
Authors: Ito H. , Watanabe Y. , Isshiki A. , Uchino H.
Published: March 2003

Background: The mechanism of the neuroprotective effects of propofol was compared to two other types of intravenous (i.v.) anesthetics (i.e., benzodiazepine; midazolam and barbiturate; pentobarbital) using Mongolian gerbils focusing on GABA receptor subtypes.

Methods: Neuronal injury was induced by a 4‐min occlusion of the common carotid arteries followed by reperfusion. One week after occlusion, animals were transcardially perfused for histochemistry. Neuronal death in four brain regions was evaluated by direct visual counting of acidophilic neurons.

Results: Seven days after this ischemic episode, severe neuronal injury was measured in the hippocampal CA1 area (>98% of total cells damaged) and parietal cortex (>35%). Also lateral thalamus and caudate putamen were damaged but to a lesser extent (about 10%). The neuronal injury in these areas was significantly attenuated by propofol, midazolam and the GABAA agonist, muscimol, intraperitoneally administered 15 min prior to ischemia. This neuroprotective property, however, was lacking with pentobarbital and GABAB agonist baclofen. Concomitant pretreatment with subthreshold doses of propofol and muscimol significantly reduced the amount of cell death induced by brain ischemia. On the other hand, pretreatment with the GABAA antagonist bicuculline significantly inhibited the neuroprotective effects of propofol. However, a GABAB antagonist, phaclofen, was without effect on neuronal damage and on neuronal protection of propofol.

Conclusion: These results indicate that activation of GABAA receptors, which include the specific binding subunits for propofol and midazolam, but not pentobarbital, plays a role in the inhibition of neuronal death induced by brain ischemia.
Attitudes of Swedish physicians and nurses towards the use of life‐sustaining treatment
Authors: Sjokvist P. , Berggren L. , Cook D. J.
Published: March 2003

Background: Withdrawal or withholding of life‐sustaining treatment have become accepted clinical practice within the intensive care unit (ICU). One important factor influencing these decisions is the attitudes of physicians and nurses.

Method: Questionnaire survey of physicians and nurses in ICUs in 12 Swedish university‐affiliated and/or tertiary referral hospitals.

Results: The response rate was 850 of 1081 (79%) potentially eligible health care workers. Respondents first rated the importance of 16 factors considered in the decision to withdraw life support. The most important factors were the patient’s likelihood of surviving the current episode, patient advance directives, patient age and likelihood of long‐time survival. Respondents also chose between five levels of care, ranging from comfort measures to full intensive care, in two of 12 different scenarios. Respondent characteristics affecting the level of care chosen were the number of years of ICU experience and the particular ICU in which the respondent worked.

Conclusion: Advance directives are believed by Swedish intensive care personnel to be very important in the decision to withdraw life support, contrary to several descriptive studies suggesting modest patient and family influence on these decisions. Attitudes towards the intensity of care vary between different centers, raising the possibility that levels of care for similar patients may differ across the country.
A review of recovery from sevoflurane anaesthesia: Comparisons with isoflurane and propofol includingmeta‐analysis
Authors: Robinson B. J. , Uhrich T. D. , Ebert T. J.
Published: March 2003

Background: Sevoflurane has a lower blood:gas partition coefficient than isoflurane and thus should be associated with a more rapid recovery from anaesthesia.

Methods: A review and meta‐analysis were employed to examine the recovery profiles of adult patients following anaesthesia, comparing sevoflurane to isoflurane and sevoflurane to propofol.

Results: There were significant differences in times to several recovery events that favoured sevoflurane to isoflurane anaesthesia, including time to emergence, response to commands, extubation, and orientation. Likewise, there were significant differences in times to the same recovery events following anaesthesia with sevoflurane versus propofol. There were no differences in time to recovery room discharge when comparing sevoflurane to isoflurane or propofol.

Conclusion: The observed differences between sevoflurane and isoflurane or propofol anaesthesia support the postulate that the use of sevoflurane is associated with a more rapid recovery from anaesthesia than either isoflurane or propofol.
Cost consciousness among anaesthetic staff
Authors: Schlünzen L. , Simonsen M. S. , Spangsberg N. L. M. , Carlsson P.
Published: March 2003

Background: Anaesthetists, like all other specialists, need to be aware of the costs of drugs, fluids and disposables commonly used in their clinical practice so that excessive costs and waste can be minimized without compromising patient care or safety. The present study describes cost consciousness among 120 anaesthetic staff members in two Danish anaesthetic departments.

Method: A prospective study questioning 120 anaesthetic staff members (69 anaesthetic nurses, 35 senior anaesthetists and 16 junior anaesthetists) about the costs of 29 drugs, fluids and disposable used in routine anaesthetic practice.

Results: After the study period 107 questionnaires (90%) were available for analysis. Thirty‐eight percent of all estimated costs were within 50% of the actual costs and 85% were within 100%. The costs of relatively expensive items such as isoflurane, enflurane, sevoflurane and hydroxyethyl starch were consistently underestimated, whereas cheaper items such as narcotic drugs, endotracheal tubes, intravenous tubing, plastic syringes and Quincke spinal needle were consistently overestimated. In general, the anaesthetic staff overestimated the costs by 69% (range −24% to 270%). The anaesthetic nursing group overestimated the costs by 49% (range −24% to 270%), junior anaesthetists by 94% (range 25% to 226%) and senior anaesthetists by 72% (range −14% to 135%).

Conclusion: This study shows that the overall consciousness of the costs of anaesthetic drugs, fluids and disposables has to be improved in order to permit the staff to optimize resources.
Prolonged dysequilibrium between blood and brain concentrations of propofol during infusions in sheep
Authors: Ludbrook G. L. , Upton R. N. , Grant C. , Martinez A.
Published: March 2003

Background: Previous work had shown dysequilibrium between the arterial blood and brain concentrations of the intravenous anaesthetic agent propofol following its rapid administration over 2 min to sheep. The extent of dysequilibrium was examined following slower administration as a constant rate 45‐min infusion (10 mg/min).

Methods: Six sheep were prepared with arterial and sagittal sinus (effluent from the brain) blood sampling catheters and a Doppler flow probe for measuring an index of cerebral blood flow. Propofol concentrations in arterial and sagittal sinus blood during and after the infusions were measured using high‐performance liquid chromatography with fluorescence detection. Brain concentrations were calculated from these concentrations and cerebral blood flow using direct mass balance methods.

Results: There was dysequilibrium between the arterial blood and brain concentrations until approximately 30 min after the start of the infusion, with marked hysteresis between the arterial blood and brain concentrations for the duration of the study. The equilibrium half‐life between the blood and the brain was 3.5 min, which is comparable to the value of 4.3 min derived from the earlier rapid administration data, suggesting there was no time dependency in the kinetics of cerebral uptake. The mass of propofol entering the brain via arterial blood was the same as the mass leaving the brain via sagittal sinus blood, suggesting minimal metabolism of propofol in the brain of sheep.

Conclusion: It is clear that pharmacokinetic analysis based on arterial blood concentrations alone cannot accurately account for the concentrations of propofol at its site of action in the brain.
Topical wound anaesthesia in children – a temporary postoperative pain relief
Authors: Kokinsky E. , Cassuto J. , Sinclair R. , Rubensson A. , Nilsson K. , Larsson L. E.
Published: March 2003

Background: Administration of local anaesthetics into the surgical wound may modulate pain at the peripheral level. A previous study in adults has shown good analgesic effects of topical lidocaine in wounds after herniorraphy.

Methods: Postoperative pain relief after topical administration of 10% lidocaine aerosol in the surgical wound was investigated in a randomised, double‐blind study in children undergoing inguinal hernia repair. Forty‐four patients aged between 9 months and 11 years were randomised into three groups. One group received active treatment with a lidocaine aerosol 2.5–4.7 mg kg −1, one group received a placebo aerosol and one control group was untreated. Postoperative pain was evaluated by nurse assessment, self‐assessment and wound palpation 0, 1, 4 and 12 h after arrival in the recovery room.

Results: After 1 h the incidence of pain, as estimated by behavioural assessment and self‐assessment, was significantly reduced in the lidocaine group in comparison to the placebo group, but not in comparison to the control group. The reaction on wound palpation was significantly reduced in the lidocaine group compared to both the placebo and control groups. At 0, 4 and 12 h no significant differences between the groups were observed. Plasma lidocaine concentrations were measured in six patients. Maximum individual concentrations were low, ranging from 0.17 to 0.86 μg ml−1.

Conclusion: A very short and clinically insignificant pain relief is obtained following the administration of a lidocaine aerosol in the surgical wound. A low pain level in this model may limit the possibility to detect an effect of lidocaine.
Continuous interscalene brachial plexus block for postoperative analgesia following shoulder surgery
Authors: Lehtipalo S. , Koskinen L‐O. D. , Johansson G. , Kolmodin J. , Biber B.
Published: March 2003

Background: Severe postoperative pain is a well‐known problem following shoulder surgery. This study evaluates the clinical efficacy of continuous interscalene brachial plexus block, patient‐controlled analgesia, and morphine (i.v. and i.m.) for postoperative analgesia in this setting.

Methods: Thirty patients, scheduled for acromioplasty during general anesthesia, were randomly allocated to one of three different postoperative pain management groups. Group MO received morphine (5 mg i.m. and 2 mg i.v.) when visual analogue pain score (VAS) >3, group PL received a continuous interscalene brachial plexus block with bupivacaine (1.25 mg kg−1+0.25 mg kg−1 h−1) and group PCA received patient‐controlled analgesia with morphine (bolus 1 mg). Postoperative pain relief was assessed (24 h) by VAS, circulatory and respiratory stress parameters (heart rate, systemic arterial pressure and respiratory rate) and stress metabolites (glucose, lactate, glycerol by abdominal subcutaneous microdialysis).

Results: Pain relief in the PL group was effective (VAS <3) and significantly more potent than in groups MO and PCA, except at 16 and 20 h. Lactate was significantly increased in the PL group, glucose was significantly increased in all groups, while glycerol showed a variable pattern. There were no significant stress metabolite differences among groups. VAS showed no statistical correlation with microdialysate, respiratory or circulatory data.

Conclusion: Successful continuous interscalene brachial plexus block provides very good pain relief following shoulder surgery and is superior to the other methods studied. However, we were unable to demonstrate a correlation between VAS pain scores and stress indicators in metabolic, circulatory and respiratory parameters.
Comparative effects of intravenous ketorolac and pethidine on perioperative analgesia and postoperative nausea and vomiting (PONV) for paediatric strabismus surgery
Authors: Shende D. , Das K.
Published: March 2003

Background: Corrective strabismus surgery is associated with moderate pain and a very high incidence of postoperative nausea and vomiting (PONV). Ketorolac tromethamine, a non‐steroidal anti‐inflammatory drug, is a popular analgesic in adults. There are only limited published data on the use of intravenous ketorolac for paediatric analgesia perioperatively. This study evaluated and compared the emetic and analgesic effect of ketorolac with pethidine and its suitability for this kind of surgery.

Methods: Following institutional ethics committee approval and parental consent, 52 ASA class I children of age 2.5 to 15 yr were randomised to receive either ketorolac 0.9 mg kg−1 or pethidine 0.5 mg kg−1 given intravenously (IV). A blinded observer assessed recovery by Steward’s method immediately after arrival at the post anaesthesia care unit (PACU), pain by validated Objective Pain Score (OPS) at 0 h, 1/2 h and 1 h after arrival at the PACU and PONV by Numeric Rank Score at specified time intervals.

Results: There were no differences in demographic data, anaesthesia time or surgery duration. Recovery scores, OPS and postoperative analgesic requirement were similar in both groups. PONV at various time intervals for the first 24 h, occurred more frequently in the pethidine group as compared to the ketorolac group (P<0.001) There were no side effects observed with either drug.

Conclusion: Ketorolac in a dose of 0.9 mg kg−1 IV at the induction of anaesthesia is as effective as pethidine 0.5 mg kg−1 IV as an analgesic and is associated with significantly less PONV.
Effect and placebo effect of acupressure (P6) on nausea and vomiting after outpatient gynaecological surgery
Authors: Alkaissi A. , Stålnert M. , Kalman S.
Published: March 2003

Background: Acupuncture and acupressure have previously been reported to possess antiemetic effect. We wanted to investigate the “true” and placebo effect of acupressure in prevention of postoperative nausea and vomiting (PONV).

Patients and methods: Sixty women undergoing outpatient minor gynaecological surgery were entered into a double‐blind and randomised study. One group received acupressure with bilateral stimulation of P6 (A), a second group received bilateral placebo stimulation (P) and a third group received no acupressure wrist band and served as a reference group (R). PONV was evaluated as number of patients with complete response (no PONV), nausea only or vomiting. In addition, the need for rescue antiemetic medication and nausea after 24 h was registered.

Results: Complete response was obtained in 11, 11 and 9 patients in groups, A, P and R, respectively. Nine, 7 and 6 patients had nausea before discharge home, and 1, 1 and 8 patients were nauseated (8 vs 1 patient: P<0.05 ) 24 h after operation in A, P and R groups, respectively. When compared to placebo acupressure (2 patients vomited and 5 needed rescue), significantly (P<0.05) fewer needed rescue antiemetic medication after acupressure at P6 (no vomiting or rescue medication). When compared to the observation group (5 vomited and 4 needed rescue antiemetics), significantly fewer vomited after acupressure (P<0.05)

Conclusion: In patients undergoing brief gynaecological surgery, placebo effect of acupressure decreased nausea after 24 h but vomiting and need of resuce antiemetics was reduced only by acupressure with the correct P6 point stimulation.
The role of nitric oxide in sepsis – an overview
Authors: Kirkebøen K. A. , Strand Ø. A.
Published: March 2003

Nitric oxide (NO) is normally produced in the endothelium by the constitutive isoform of the NO synthase. This physiological production of NO is important for blood pressure regulation and blood flow distribution. Several lines of evidence suggest that a hyperproduction of NO by the inducible form of NO synthase (iNOS) may contribute to the hypotension, cardiodepression and vascular hyporeactivity in septic shock. Lipopolysaccarides and cytokines, such as tumor necrosis factor, interleukin‐1 and interferon‐γ, have been shown to induce iNOS in the endothelium, vascular smooth muscle cells, macrophages and different parenchymal cells. Treatment with inhibitors of NO synthesis has been shown to improve hemodynamic variables and survival in several animal models of septic shock. In human septic shock, inhibition of NO synthesis has been shown to alter hemodynamic variables in short‐term studies, but it is uncertain whether this treatment has beneficial long‐term effects. The aim of this review is to give an overview of the physiological role of NO and to discuss the role of NO in sepsis and the potential therapeutic implications of NO as a target in treatment of human septic shock. A main new aspect of this review is a critical discussion of previous reports measuring plasma nitrite/nitrate during septic shock and an evaluation of the validity of interpreting these data as evidence for a hyperproduction of NO. This review also emphasizes that many septic patients have preexisting endothelial dysfunction and lung diseases, which may contribute to adverse effects by systemic inhibition of NO synthesis. Another new aspect of the present review is a focus on the lack of direct evidence of iNOS expression in human septic shock.
Production of nitrogen dioxide during nitric oxide therapy using the Servo Ventilator 300 during volume‐controlled ventilation
Authors: Lindberg L. , Rydgren G.
Published: March 2003

Background: Inhaled nitric oxide may be useful in the treatment of pulmonary hypertension and hypoxaemia. Nitric oxide is rapidly oxidized to nitrogen dioxide, which is toxic and may adversely affect the airways of the patient. The aim of the present investigation was to examine factors that may affect the concentration of nitrogen dioxide, using the Servo Ventilator 300 nitric oxide delivery system, where nitric oxide is flow‐proportionally mixed with the main ventilatory flow in the proximal part of the inspiratory limb.

Methods: In this experimental study nitric oxide and nitrogen dioxide levels were measured at the inspiratory site of a Y‐piece with a chemiluminescence analyzer and electrochemical fuel cells. The effects of different concentrations of nitric oxide and oxygen, minute volume, different tube lengths, a soda lime absorber, and a humidifier placed in the inspiratory limb were evaluated.

Results: The concentration of nitrogen dioxide was dependent on the concentrations and residence time of nitric oxide with oxygen and the minute volume ventilation used. A soda lime absorber reduced concentrations of nitrogen dioxide at the expense of almost corresponding reductions in inhaled concentrations of nitric oxide. A humidifier increased the concentration of nitrogen dioxide, to an extent depending on the water volume and temperature used.

Conclusion: Concentrations of nitric oxide and oxygen, minute volume ventilation, and residence time in the inspiratory part of the ventilatory circuit were factors that affected the generation of nitrogen dioxide. A soda lime absorber in this system is not recommended.
Positive end‐expiratory pressure prevents atelectasisduring general anaesthesia even in the presence of a high inspired oxygen concentration
Authors: Neumann P. , Rothen H. U. , Berglund J. E. , Valtysson J. , Magnusson A. , Hedenstierna G.
Published: March 2003

Background: General anaesthesia impairs the gas exchange in the lungs, and moderate desaturation (SaO2 86–90%) occurred in 50% of anaesthetised patients in a blinded pulse oximetry study. A high FiO2 might reduce the risk of hypoxaemia, but can also promote atelectasis. We hypothesised that a moderate positive end‐expiratory pressure (PEEP) level of 10 cmH2O can prevent atelectasis during ventilation with an FiO2=1.0.

Methods: Atelectasis was evaluated by computed tomography (CT) in 13 ASA I–II patients undergoing elective surgery. CT scans were obtained before and 15 min after induction of anaesthesia. Then, recruitment of collapsed lung tissue was performed as a “vital capacity manoeuvre” (VCM, inspiration with Paw=40 cmH2O for 15 s), and a CT scan was obtained at the end of the VCM. Thereafter, PEEP=0 cmH2O was applied in group 1, and PEEP=10 cmH2O in group 2. Additional CT scans were obtained after the VCM. Oxygenation was measured before and after the VCM.

Results: Atelectasis (>1 cm2) was present in 12 of the 13 patients after induction of anaesthesia. At 5 and 10 min after the VCM, atelectasis was significantly smaller in group 2 than group 1 (P<0.005). A significant inverse correlation was found between PaO2 and atelectasis.

Conclusions: PEEP=10 cmH2O reduced atelectasis formation after a VCM, when FiO2=1.0 was used. Thus, a VCM followed by PEEP=10 cmH2O should be considered when patients are ventilated with a high FiO2 and gas exchange is impaired.
Intraoperative glucose administration influences respiratory quotient during paediatric anaesthesia
Authors: Sandström K. , Larsson L. E. , Nilsson K. , Stenqvist O.
Published: March 2003

Background: Oxidation of carbohydrates and fat yields respiratory quotients (RQ) of 1.0 and 0.7 respectively. Maintained or increased blood glucose concentrations are usually seen during paediatric anaesthesia and surgery even without glucose administration. The aim of the present study was to evaluate whether an intraoperative glucose infusion influences the RQ as an indication of a different metabolic preference in comparison to a glucose‐free fluid regime.

Methods: Eighteen children between 0.5 and 24 months of age were studied during anaesthesia with controlled ventilation, oxygen in air, isoflurane, thiopentone, atracurium and fentanyl. Oxygen consumption and carbon dioxide production were measured using indirect calorimetry All children received Ringer acetate as needed; in addition, nine children were given glucose 10%, 3 ml  ·  kg−1  ·  h−1, corresponding to 300 mg  ·  kg−1  ·  h−1. Blood samples for analyses of glucose, lactate, free fatty acids and ketones were taken before and during surgery.

Results: RQ was significantly higher in the children given glucose 0.92±0.08, compared to 0.81±0.06 in the children without glucose (P<0.01). Oxygen consumption tended to be higher, although not significantly so, in patients without glucose infusion. Energy expenditure was 1.70±0.29 kcal  ·  kg−1  ·  h−1, without significant group differences. Higher blood glucose concentrations during surgery were found in the children given glucose.

Conclusions: Our results indicate a higher glucose oxidation rate in patients given glucose during surgery.
Single‐dose spinal anaesthesia versus incremental dosing for lower limb vascular surgery
Authors: Lundorff L. , Dich‐Nielsen J. O. , Laugesen H. , Jensen M. M.
Published: March 2003

Background: In patients scheduled for vascular surgery, atherosclerotic disease is highly prevalent. Haemodynamic reactions are often aggravated when spinal analgesia is used in this population. No randomized studies have been conducted comparing single shot (SS) with continuous spinal analgesia (CSA) for vascular patients. We did a prospective randomized study comparing haemodynamics when SS versus CSA was performed.

Methods: Sixty patients were randomized to have SS or CSA. The power of the study was 0.90. Patients in the SS group received 17.5 mg bupivacaine and in the CSA group 5 mg was given initially and incremental doses of 2.5 mg were given until an analgesic level of T‐11 was reached. Mean arterial pressures (MAP) were measured invasively. ST‐analysis was done continuously. Postoperatively, the patients were interviewed using a standardized questionnaire. Back pain, neurologic sequelae and post‐dural puncture headache (PDPH) were investigated.

Results: There was no significant difference between the analgesic levels (T‐7/T‐8), the decrease in MAP, the number of patients needing ephedrine and the total amount of ephedrine given in the two groups. The motor blockade was more pronounced in the SS group (P<0.001) and the total amount of bupivacaine used was 17.5 mg compared to 7.5 mg (5–17.5) in the CSA group (P<0.001). One patient suffered PDPH which was slight and responded to a nonsteroidal anti‐inflammatory drug. Two patients in each group had transient paraesthesias in the legs. There were technical problems with the spinal catheter in 4 patients, and these were excluded from the study.

Conclusion: In this study we found no difference in the haemodynamic response to SS or CSA in patients scheduled for vascular surgery of the legs. SS is easier to apply and is recommended when the duration of surgery allows for it.
The sevoflurane‐sparing effect of nitrous oxide: a clinical study
Authors: Jakobsson J. , Heidvall M. , Davidson S.
Published: March 2003

Background: We studied the sevoflurane‐sparing effect of nitrous oxide in a prospective randomised study.

Methods: Forty‐two ASA I–II patients scheduled for elective knee arthroscopy under general anaesthesia were randomly assigned to a fresh gas flow consisting of oxygen in air or oxygen in nitrous oxide 1:2. All patients received a standardised anaesthesia consisting of induction with fentanyl and propofol and maintenance with sevoflurane adjusted according to clinical signs. The sevoflurane consumption was studied by means of weighing the vaporiser before and after every anaesthesia.

Results: The mean sevoflurane consumption was reduced from 0.62 to 0.25 g/min, a 60% reduction, by the use of oxygen in nitrous oxide 1:2 in the fresh gas flow. The emergence was faster for the patients receiving nitrous oxide. No major differences were observed during recovery.

Conclusion: Nitrous oxide was found to be cost‐effective for use during short ambulatory knee arthroscopy.
Local vascular response during organ elevation
Authors: Kongstad L. , Grände P.‐O.
Published: March 2003

Background: Dural puncture can be followed by postural headache and, in patients with cerebral infections, by brain stem herniation. The present study evaluates whether these complications may be related to the changes in hydrostatic pressure generated by the spinal fluid column when the dural sac surrounding the cerebrospinal tissue has been punctured.

Method: An isolated cat skeletal muscle enclosed in a plethysmograph connected to a tube served as a model imitating the brain, the cranium and the spinal canal. We investigated effects of organ elevation on tissue pressure, venous collapse (venous outflow resistance) and tissue volume with closed “spinal” tube (intact dural sac) and open “spinal” tube (dural puncture), and effects of compliance of the draining veins.

Results: Organ elevation with closed “spinal” tube induced a decreased tissue pressure, whereas tissue pressure remained unchanged if arterial inflow pressure to the muscle was kept constant. Organ elevation with the “spinal” tube opened distally caused a significantly larger decrease in tissue pressure, venous dilation and disappearance of venous outflow resistance. Transcapillary filtration increased, and the filtration rate was higher with high than with low venous compliance.

Conclusion: If our results are applicable to the brain, changing to an upright position following a lumbar dural puncture may generate a negative hydrostatic force and a negative interstitial cerebral pressure, causing an increased transvascular pressure and dilation of the cerebral outflow veins. The corresponding increase in cerebral blood volume may induce post‐spinal headache, and the increased transcapillary pressure may cause increased fluid filtration and brain oedema if the blood‐brain barrier is disrupted.
Irrigation fluid absorption during transurethral resection of the prostate: Spinal vs. general anaesthesia
Authors: Gehring H. , Nahm W. , Baerwald J. , Fornara P. , Schneeweiss A. , Roth‐Isigkeit A. , Schmucker P.
Published: March 2003

Background: The absorption of irrigation fluid during transurethral resection of the prostate (TURP) is determined primarily by hydrostatic pressure in the bladder and prostatic venous pressure. In comparison to spontaneously breathing patients, patients undergoing mechanical ventilation with positive pressure have a raised central venous pressure and a reduced venous return, both of which can influence intravascular absorption. The purpose of the prospective study was to compare the effects of general (GA) and spinal anaesthetic (SA) techniques on the perioperative absorption of irrigating fluid in patients undergoing TURP.

Methods: Forty patients undergoing TURP were randomised and assigned either to group GA or SA. Irrigating fluid absorption was traced by adding 1.5% (w/v) ethanol to the irrigating fluid. Perioperative blood ethanol concentration (BEC), haemoglobin concentration, haematocrit, serum sodium concentration and central venous pressure (CVP) were measured at 10‐min intervals during TURP and at 30‐min intervals while patients were recovering. Absorption routes were indexed by the BEC and changes in serum sodium concentrations. Where the BEC was greater than 0.05 mg · mL−1, absorption of irrigating fluid was assumed. For assessing the volume of irrigating fluid absorbed, the maximum BEC, the absorption rate, the area under the BEC curve (AUC), and the volumes calculated according to the Hahn nomogram (Volin) for each patient were taken into consideration.

Results: There were 15 cases of irrigating fluid absorption in patients receiving GA (75%), and 11 in those receiving SA (55%). CVP was significantly lower in spontaneously breathing patients with SA as compared to those with GA (P<0.05). In patients with irrigating fluid absorption the maximum BEC (P<0.02), as well as the rate of irrigant fluid absorption (P<0.01), were significantly higher amongst patients receiving SA. In this group, the calculated area under the curve and the absorbed fluid volumes determined with the nomogram were significantly increased (P<0.05).

Conclusion: The absorption of irrigation fluid during the TURP is significantly more marked amongst spontaneously breathing patients with regional anaesthesia in comparison to patients undergoing general anaesthesia with positive pressure ventilation. The markedly lower central venous pressure before the start of irrigation should be considered as a possible cause of this effect.
A comparison of the monitors INVOS 3100 and NIRO 500 in detecting changes in cerebral oxygenation
Authors: Grubhofer G. , Tonninger W. , Keznickl P. , Skyllouriotis P. , Ehrlich M. , Hiesmayr M. , Lassnigg A.
Published: March 2003

Background: Measurements of cerebral haemoglobin oxygenation of 2 near‐infrared spectroscopy devices (INVOS 3100 and NIRO 500) were compared during and after hypocapnia.

Methods: Fifteen awake, healthy volunteers, who hyperventilated to obtain end‐tidal CO2 (EtCO2) values of approximately 20 mmHg, were studied. During hyperventilation and 8 min thereafter, EtCO2, INVOS 3100 (RSO2=regional cerebral oxygenation) and NIRO 500 recordings (HbO2=oxyhaemoglobin, Hb=deoxyhaemoglobin, Hb‐diff=HbO2–Hb, CtO2=oxidised cytochrome oxidase aa3) were analysed.

Results: Hyperventilation induced a significant decline in EtCO2 from 30.5 to 14.7 mmHg (P<0.001) and RSO2 from 67.1% to 62.7% (P=0.025). At hypocapnia, only Hb (+1.61±0.48 μmol/L; P<0.001) and Hb‐diff (−3.01±2.0 μmol/L; P<0.001) indicated a decline in cerebral haemoglobin oxygenation. Within 8 min after hyperventilation, both EtCO2 and RSO2 normalised to values insignificantly different from baseline. In contrast, Hb and Hb‐diff remained significantly different (Hb: +2.52±1.28 μmol/l; P<0.001, Hb‐diff: −4.31±4.0 μmol/L; P<0.001). A correlation with EtCO2 was found for RSO2 (R=0.35; P<0.001) and CtO2 (R=0.42; P<0.001). All volunteers were continuously awake and none presented clinical symptoms of cerebral hypoxia.

Conclusion: Changes in cerebral haemoglobin oxygenation state were reflected more accurately by INVOS 3100 than NIRO 500. The cause may be the different technology of the monitors, since INVOS 3100 eliminates the contribution of extracranial oxygenation.
Methemoglobinemia after axillary block with bupivacaine and additional injection of lidocaine in the operative field
Authors: Schroeder T. H. , Dieterich H.‐J. , Mühlbauer B.
Published: March 2003

Methemoglobinemia may occur after the administration of various drugs, including some local anesthetics. We report a patient with chronic renal failure and ischemic heart disease who developed clinically significant methemoglobinemia after an axillary block with bupivacaine and additional injection of lidocaine in the operative field. Although the two local anesthetics usually do not cause methemoglobinemia, we suspect that the displacement of lidocaine from protein binding by bupivacaine, in combination with metabolic acidosis and treatment with other oxidants, was the reason for the development of methemoglobinemia.
Effect of prostaglandin E1 and nitroglycerin on portal venous flow during hypothermic extracorporeal circulation: Assessment by transesophageal echography
Authors: Iribe G. , Ohnishi Y. , Hayashi Y. , Kuro M.
Published: March 2003

Background: Although several vasodilators are used to control vascular resistance during cardiac surgery, their effects on splanchnic circulation during extracorporeal circulation are unknown. We designed the present noninvasive study to evaluate the effect of prostaglandin E1 and nitroglycerin on portal venous flow during extracorporeal circulation using transesophageal echography.

Methods: We included 26 patients undergoing cardiac surgery with moderate hypothermic extracorporeal circulation in this study. After obtaining hemodynamic stability under extracorporeal circulation, we measured portal venous diameter, mean flow velocity and the velocity time integral using transesophageal echography and calculated portal venous flow. The patients were assigned to two groups where either prostaglandin E1 (N=13) or nitroglycerin (N=13) was administered intravenously to maintain perfusion pressure at the level of 70 mmHg. We measured the same parameters 20 and 40 min following administration of the drug.

Results: Visualization of the portal vein was obtained by transesophageal echography in anesthetized patients. Calculated portal venous flow significantly increased in the prostaglandin E1 group, while it did not alter in the nitroglycerin group.

Conclusion: The present results indicate that transesophageal echography may be a feasible tool to assess portal venous flow, and that prostaglandin E1 may improve the blood distribution to the splanchnic area and the liver during hypothermic extracorporeal circulation.
Sevoflurane causes more postoperative agitation in children than does halothane
Authors: Beskow A. , Westrin P.
Published: March 2003

Background: An agitated recovery may occur after inhalation anesthesia. The aim of the present study was to assess the recovery quality after mask anesthesia with either halothane or sevoflurane in children.

Methods: Sixty‐two children, 8 months to 18 years of age, scheduled for minor surgery, were randomly assigned to receive either halothane or sevoflurane. The patients were premedicated with midazolam and anesthesia was induced iv with propofol or by inhalation and maintained with halothane or sevoflurane in N2O/O2 via face mask. Recovery was assessed by a “blinded” observer using a postanesthetic recovery score. Agitation and pain were judged using a visual analog scale. The incidence of vomiting was noted. The day after anesthesia older children and parents of younger children were interviewed about their experience of the anesthesia and recovery period.

Results: There were no differences between groups in respect of age, weight, length, or duration of surgery or inhalational gas exposure. Median time from end of administration of inhalational agent to spontaneous eye opening was less after sevoflurane (25 min) than after halothane (48 min), (P<0.01). Likewise, recovery was faster after sevoflurane anesthesia (P<0.05). Agitation, but not pain, occurred more frequently after sevoflurane than after halothane (P<0.05) and agitation was significantly more common in younger children. There was no difference in duration of hospital stay between day‐care patients in the two groups.

Conclusion: Early postanesthetic agitation and recovery was faster after mask anesthesia with sevoflurane than after halothane. There was a higher incidence of agitation in younger children, without correlation to pain.
Continuous epidural administration of midazolam and bupivacaine for postoperative analgesia
Authors: Nishiyama T. , Matsukawa T. , Hanaoka K.
Published: March 2003

Background: Midazolam has been reported to have a spinally mediated analgesic effect. Clinically, single‐shot epidural or spinal administration of midazolam has been shown to have an analgesic effect on perioperative pain. In this study, we investigated the analgesic effect of continuous epidural administration of midazolam with bupivacaine on postoperative pain.

Methods: Four groups of 20 patients who underwent gastrectomy or cholecystectomy were studied. Continuous epidural infusion of bupivacaine 100 mg (Group C), bupivacaine 100 mg+midazolam 10 mg (Group M10), or bupivacaine 100 mg+midazolam 20 mg (Group M20) in 40 ml per 12 h was started after surgery using the balloon infuser. Group I received intermittent epidural bupivacaine (2.5 mg  ·  ml−1) 6 ml every 2 h. When necessary, an indomethacin suppository and then a single epidural shot of bupivacaine (2.5 mg  ·  ml−1) 6 ml was administered. Blood pressure, heart rate, respiratory rate, analgesic area, analgesia score, and sedation score were monitored for 12 h postoperatively. Memory and frequencies of supplemental analgesia (indomethacin suppositories and epidural bupivacaine) were also checked.

Results: Group M20 showed a significantly wider area of pinprick analgesia and better analgesia scores than other groups. The need for rescue analgesics were significantly less in Group M20. Sedation and amnesia were more pronounced in Group M20 than the other groups.

Conclusion: Adding midazolam (10 to 20 mg per 12 h) to continuous epidural infusion of bupivacaine for postoperative pain can provide a better analgesia, amnesia and sedation than bupivacaine alone.
Infiltration block for caesarean section in a morbidly obese parturient
Authors: Gautam P. L. , Kathuria S. , Kaul T. K.
Published: March 2003

We report a case of a morbidly obese parturient (150 kg and 150 cm) for emergency lower segment caesarean section for dead foetus. Her pregnancy had been unsupervised. She presented with severe pre‐eclampsia, generalized oedema and acute respiratory failure. Caesarean section was performed under infiltration block using lidocaine 0.5–1.0%. Her status improved postoperatively with aggressive physiotherapy, nursing in a semirecumbent position and oxygen supplementation.