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J Hobbhahn

Publications and source records attributed to J Hobbhahn.

At least 37 records · Page 2Linked to original sources
PubMed1998

Waste gas exposure during desflurane and isoflurane anaesthesia.

BACKGROUND: Currently, there are no data available concerning the occupational exposure to desflurane during general anaesthesia. This prospective, randomized study reports on occupational exposure to desflurane, compared to isoflurane, in a modern operation theatre (OT). METHODS: The study was performed in an OT equipped with a modern air-conditioning system and with a low-leakage anaesthesia machine connected to a central scavenging system. Trace concentrations of the anaesthetics were measured continuously by means of a photoacoustic infrared spectrometer during general anaesthesia in 30 patients undergoing eye surgery. Values were obtained within the breathing zone of the anaesthetist, the surgeon, the auxiliary nurse and at the mouth of the patient. RESULTS: Desflurane and isoflurane were administered with median (range) endtidal concentrations of 4.7 (3.8-10.3) vol% and 0.9 (0.6-1.4) vol%, respectively. The personnel-related median values of the average trace concentrations of desflurane and isoflurane were 0.5 (0.01-7.5) ppm and 0.2 (0.01-1.6) ppm, respectively. CONCLUSIONS: Occupational exposure to desflurane is low in the environment of a modern OT, even though it has to be administered in approximately 5-fold higher concentrations compared to isoflurane.

Air Conditioning↗
PubMed1998

[Biological monitoring during exposure to the anesthetics isoflurane and sevoflurane].

Exposure to traces of inhaled anaesthetic agents may impair the health of the operating theatre personnel. Although no cause-effect relationship has been found, most public health authorities recommend various occupational exposure standards to minimize possible health risks. If metabolites of the substances are known, biological monitoring is an alternative to the monitoring of the operating theatre's air. The new anaesthetic agent Sevoflurane is considerably more transformed to fluoride than Isoflurane. Concerning fluoride there exist Biological Tolerance Values of 4.0-7.0 mg fluoride (F-) per gram creatinine (Crea). The aim of our study was to compare the fluoride excretion under the occupational exposure to sevoflurane and isoflurane. By the means of a direct-reading instrument trace concentrations of sevoflurane, isoflurane, and nitrous oxide were measured during 40 anaesthetic procedures. Urine samples were collected before (Z1) and after the workshift (Z2), and in the morning of the next day (Z3). The analysis was done by the means of an ionselective electrode. The personnel-related concentrations (median, range) were 0.50 (0.16-7.04) ppm isoflurance and 27.36 (5.87-467.10) ppm nitrous oxide, and 0.79 (0.15-1.95) ppm sevoflurane and 17.74 (2.45-84.20) ppm nitrous oxide. The resulting fluoride values presented at Z1, Z2, and Z3 as median (range) during exposure to isoflurane were 0.15 (0.11-0.53), 0.19 (0.11-0.53), 0.20 (0.11-0.31) mg F-/g Crea, and 0.15 (0.10-0.46), 0.22 (0.13-0.44), 0.23 (0.15-0.69) mg F-/g Crea during exposure to sevoflurance, respectively. The trace concentrations were clearly under 10 ppm for the volatile substances and 100 ppm for nitrous oxide. The values are comparable to data recorded under similar working conditions. The measured fluoride values were low and remained under the legal tolerance values. Under the described conditions potential health risks were low.

Air Pollution, Indoor↗
PubMed1998

Intra-operative evaluation of a continuous versus intermittent bolus thermodilution technique of cardiac output measurement in cardiac surgical patients.

The purpose of this study was to analyse the clinical agreement between cardiac output measurements, obtained using a newly available continuous thermodilution technique, and the conventional intermittent bolus technique. Twenty-four cardiac surgical patients were intra-operatively monitored using both techniques. Additionally, two different averaging modes for the continuous thermodilution technique, either the previous 6 min (group 1) or 3 min (group 2) were compared. The mean difference between the continuous thermodilution technique and the intermittent bolus technique (bias), were calculated at eight selected time points. These ranged from -0.09 to 0.42 litres min-1 in group 1 and from -0.02 to 0.18 litres min-1 in group 2. There were significant differences at any time point between the groups. The relative error between continuous thermodilution and intermittent bolus techniques was < 15% for the majority of measurements and was significantly higher in group 1 compared with group 2 just prior to cardiopulmonary bypass. Thus, the continuous thermodilution technique produced a clinically acceptable level of accuracy compared with the intermittent bolus technique measurements, especially when using an averaging mode for the previous 3 min.

Aged↗
PubMed1997

Nitric oxide synthase isoform III gene expression in rat liver is up-regulated by lipopolysaccharide and lipoteichoic acid.

This study was done to investigate the influence of Gram-negative and Gram-positive sepsis on the expression of the three isoforms of nitric oxide synthase (NOS) gene in rat liver and kidney. Male Sprague-Dawley rats were treated with lipopolysaccharide (LPS, 10 mg/kg i.v.) as an in vivo model for Gram-negative sepsis or lipoteichoic acid (LTA, 10 mg/kg i.v.) as an in vivo model for Gram-positive sepsis. Animals were killed 12 h and 24 h after i.v. treatment. NOS mRNA of the three isoforms was determined by RNase protection assay. NOS II gene expression was strongly induced after LPS or LTA treatment in rat liver and kidney, indicating the efficacy of this treatment to induce sepsis. We found no change of NOS I gene expression after LPS or LTA injection in rat liver and kidney. NOS III gene expression was increased about 8-fold 12 h and about 5-fold 24 h after induction of sepsis in the rat liver whereas in the kidney there was no significant increase in NOS III gene expression. After correction for length NOS III mRNA was about 4- and 40-fold more abundant 12 h and 24 h after LPS treatment than NOS II mRNA in the liver, respectively. Twelve and 24 h after LTA treatment NOS III mRNA was about 18- and 140-fold more abundant than NOS II in the liver. These findings suggest that NOS III is an even more potent source of NO than NOS II in the liver after stimulation with LPS or LTA.

Animals↗
PubMed1997

Occupational exposure to sevoflurane and nitrous oxide in operating room personnel.

OBJECT: To quantify the exposure of operating room personnel to sevoflurane and nitrous oxide. DESIGN: Prospective study at a university hospital. METHODS: In 25 patients undergoing elective surgical procedures, anaesthesia was induced with thiopentone/etomidate, vecuronium and fentanyl and maintained with fentanyl, sevoflurance in 35% oxygen and 65% nitrous oxide (N2O). Occupational exposure to sevoflurane and N2O was measured in the breathing zone of one representative of each of three personnel groups (anaesthetist, surgeon, auxiliary nurse) by means of a direct reading instrument using photoacoustic infrared spectrometry. RESULTS: The mean trace concentrations of sevoflurane for the single anaesthetic procedures exceeded the 0.5 ppm level in more than 50% of the measurements. The 2 ppm level was not exceeded in the case of the anaesthetist and the surgeon, but was exceeded in 16% of the measurements for the auxiliary nurse. The level of 25 ppm N2O were exceeded in 28% of the measurements for the anaesthetist and in 16% of these for the surgeon and for the auxiliary nurse. CONCLUSIONS: To keep exposure low, sevoflurane and N2O were used in a modern working environment: a low-leakage anaesthesia machine, high room ventilation rates, scavenging system, no intermittent mask ventilation, low to medium concentrations of sevoflurane, and strict control of the cuff pressure. Nevertheless, exposure could not be kept under NIOSH threshold values in all cases.

Air Pollutants, Occupational↗
PubMed1997

Effects of desflurane and isoflurane on systemic vascular resistance during hypothermic cardiopulmonary bypass.

OBJECTIVE: The objective of this study was to examine the dose-related effects of desflurane and isoflurane on systemic vascular resistance during hypothermic cardiopulmonary bypass. DESIGN: Randomized, prospective trial. SETTING: University hospital. PARTICIPANTS: Sixty consenting patients, 65 years of age or older, scheduled for elective coronary artery surgery. INTERVENTIONS: Patients were randomly allocated to one of five groups to receive 0.5 or 1.0 minimum alveolar concentration (MAC) (exhaust gas concentration) desflurane or 0.5 or 1.0 MAC isoflurane during hypothermic (32 degrees to 33 degrees C) nonpulsatile cardiopulmonary bypass or to a control group that did not receive any anesthetic agent. Systemic vascular resistance index was recorded at baseline, every 2 minutes for the first 10 minutes during initial administration and every 5 minutes for another 15 minutes during maintenance of anesthesia. MEASUREMENTS AND MAIN RESULTS: In patients receiving 0.5 MAC desflurane and isoflurane, there were significant differences in systemic vascular resistance index only at 20 and 25 minutes compared with control values. In the desflurane 1.0 MAC group, significant decreases were observed at 15, 20, and 25 minutes compared with controls. In the 1 MAC isoflurane group, the 10-, 15-, 20-, and 25-minute value differed significantly from the control. There were significant decreases in systemic vascular resistance index in the 1.0 MAC groups at 20 and 25 minutes compared with 0.5 MAC values, as well. CONCLUSIONS: Equi-MAC concentrations of desflurane and isoflurane had similar effects on systemic vascular resistance; 0.5 MAC maintained systemic vascular resistance; 1.0 MAC decreased systemic vascular resistance during hypothermic cardiopulmonary bypass.

Aged↗
PubMed1997

Occupational exposure to desflurane and isoflurane during cardiopulmonary bypass: is the gas outlet of the membrane oxygenator an operating theatre pollution hazard?

We have compared occupational exposure to isoflurane and desflurane during cardiopulmonary bypass, with and without a scavenging system at the membrane oxygenator outlet. Trace concentrations of volatile anaesthetics were measured by a direct reading instrument in 40 elective heart surgery procedures. Measurements were obtained in the breathing zones of the anaesthetist and perfusionist. When a scavenging system was used, median desflurane values were less than 0.3 ppm and isoflurane values less than 0.2 ppm. Without a scavenging system values were, in general, three- (isoflurane) to five- (desflurane) fold higher. We conclude that the use of a scavenging system at the membrane oxygenator outlet can reduce occupational exposure to volatile anaesthetics. We therefore recommend routine use of scavenging devices during cardiopulmonary bypass.

Adult↗
PubMed1997

Laryngeal mask airway and uncuffed tracheal tubes are equally effective for low flow or closed system anaesthesia in children.

Low flow and closed system anaesthesia have considerable advantages in economy, limited atmospheric pollution, and maintenance of humidification and temperature. To benefit from these techniques leakage from the breathing system should be as low as possible. The sealing of the airway is crucial to ensure this. Therefore, we have investigated in 30 children, aged 2-6 yr, the effectiveness of the laryngeal mask airway (LMA) and the uncuffed tracheal tube (TT) for closed system paediatric anaesthesia, during positive pressure ventilation, in a prospective, randomized study. Ventilation was adequate in all cases with both devices. Loss of gas from the breathing system was less than 100 ml min-1 in 13 (87%) patients in the LMA and in 12 (80%) patients in the TT group, with a maximum of approximately 700 ml min-1 in the TT and approximately 350 ml min-1 in the LMA group. We conclude that the airway sealing with both devices was tight enough to perform low flow or closed system anaesthesia in paediatric patients aged 2-6 yr.

Anesthesia, Closed-Circuit↗
PubMed1997

Effects of rapid increases of desflurane and sevoflurane to concentrations of 1.5 MAC on systemic vascular resistance and catecholamine response during cardiopulmonary bypass.

BACKGROUND: Airway irritation was hypothesized to trigger the transient cardiovascular stimulation associated with desflurane. The authors administered desflurane during cardiopulmonary bypass (CPB), thus avoiding airway contact, and compared the effects of rapid increases of desflurane to 1.5 MAC on systemic vascular resistance index (SVRI) and catecholamine response to those of 1.5 MAC sevoflurane. METHODS: Forty-eight patients, undergoing elective coronary bypass surgery, were randomly allocated to receive either desflurane or sevoflurane during hypothermic (32-33 degrees C) nonpulsatile CPB at exhaust gas concentrations of 1.5 MAC for 15 min. SVRI was calculated at baseline, 1, 2, 3, 4, 5, 7, 9, 12, and 15 min after starting volatile anesthetics' delivery. Plasma catecholamine concentrations were determined in 12 desflurane-treated patients and 12 sevoflurane-treated patients at baseline, 5, and 15 min. RESULTS: The time-course of deltaSVRI, (changes in SVRI from baseline), from baseline to 5 min was significantly different between desflurane- and sevoflurane-treated patients, whereas there was no difference from 7 to 15 min. In the desflurane group, SVRI from 1 to 7 min remained unchanged to baseline level, thereafter declining to significantly lower values at 9, 12, and 15 min compared with values from 0 to 5 min, whereas sevoflurane produced an immediate and significant reduction in SVRI. With desflurane, catecholamine concentrations remained unchanged to baseline level at 5 and 15 min; with sevoflurane, they decreased with time. CONCLUSIONS: The authors' results indicate that desflurane is associated with a different hemodynamic and catecholamine response compared with sevoflurane when administered into the oxygenator's gas supply line during CPB.

Aged↗
PubMed1997

Occupational exposure to sevoflurane, halothane and nitrous oxide during paediatric anaesthesia. Waste gas exposure during paediatric anaesthesia.

We report the findings of a study on exposure of operating room staff to sevoflurane, halothane and nitrous oxide during induction and maintenance of anaesthesia in children. Concentrations of anaesthetic agents in the operating theatre were measured directly by highly sensitive, photoacoustic infrared spectrometer during 20 anaesthetics. Samples were taken from the breathing zones of the anaesthetist and the circulating nurse. The operating theatre was of modern design with an air conditioning system providing 20 changes of air each hour. The threshold values of 100 ppm N2O, 50 ppm isoflurane and 10 ppm halothane recommended by the United Kingdom Committee for Occupational Safety and Health (COSH) were exceeded in several cases for a short time during mask induction. After tracheal intubation, trace concentrations of sevoflurane, halothane and N2O were mostly under the recommended levels and comparable to levels measured during adult anaesthesia.

Adult↗
PubMed1996

[Sevoflurane or halothane in inhalational anesthesia induction in childhood. Anesthesia quality and fluoride level].

UNLABELLED: Due to its low blood:gas partition coefficient (0.69) and its neutral odor, sevoflurane (S) is suitable for inhalational induction of anaesthesia. At the moment halothane (H) is preferentially used for this purpose due to its non-irritating odor and the smoothness of anaesthetic action. However, experience is limited with the use of S in children, and concern exists about potential renal toxicity of its metabolite, i.e. fluoride. Therefore, we compared S and H in an open, randomized phase III trial. MATERIAL AND METHODS: With approval of the ethics committee and written informed parental consent, 40 children (age 1-10, mean 5.3 years, ASA class I and II) had anaesthesia induced without premedication (fresh gas flow 6 l/min, N2O/O2 = 65/35). Concentration of volatile anaesthetics was increased every 3-5 breaths (S: 0.8...3.2 vol%, H: 0.4...1.6 Vol%). The ciliary reflex was tested until it disappeared. Airway reflexes and excitation were quantified using a score. Upon venipuncture, relaxation and intubation, anaesthesia was maintained with S (Fi: 2.4 vol%) or H (Fi: 1.2 vol%) in N2O/O2 (3 l/min, etCO2 35-38 mm HG). Alfentanil was supplemented in repeated doses of 20 micrograms/kg. ECG, NIBP, SpO2, Fi and Fet of CO2 and volatile anaesthetics were continuously recorded. At the end of surgery anaesthetics were terminated abruptly and fresh gas flow was increased to 6 l/min O2. Time to the first purposeful movement was registered. Serum fluoride levels were determined immediately after venipuncture, at the end of surgery and 70 min later. Time to possible discharge from the PACU was quantified using a modified Aldrete score. Data were analysed with descriptive methods, Student's t-test or non-parametric tests as appropriate. RESULTS: Groups did not differ with respect to age, weight, sex, or type of surgery. Total dose of anaesthetics was 1.60 MACxh for S and 1.77 MACxh for H (p = 0.68). Table 6 shows the essential data. Mean arterial blood pressures and heart rate remained within +/- 20% of age-related normal values (Table 7). Mean serum fluoride level was 23.1 +/- 1.2 mumol/l at the end of surgery and decreased to 18.6 +/- 0.970 min later (Fig. 3). CONCLUSIONS: Sevoflurane is an alternative to halothane in pediatric inhalational anaesthesia, with a comparable, low incidence of airway irritation and smoothness of induction. Because of the significantly faster induction and recovery it seems superior to halothane. With the fluoride levels measured, an impairment of renal function is unlikely.

Anesthesia Recovery Period↗
PubMed1996

[Serum fluoride concentrations and exocrine kidney function with sevoflurane and enflurane. An open, randomized, comparative phase III study of patients with healthy kidneys].

UNLABELLED: Sevoflurane is a "new" volatile inhaled anaesthetic. Owing to its lower blood-gas solubility coefficient, emergence from anaesthesia is faster with sevoflurane than with isoflurane, enflurane, or halothane. Sevoflurane undergoes metabolic biodegradation, releasing inorganic fluoride ions that could produce nephrotoxicity. In this study, we compared serum inorganic fluoride concentrations (IFCs) in patients receiving either sevoflurane or enflurane. Furthermore, indices of renal function were evaluated until the 3rd postoperative day. METHODS: Thirty patients with no history of renal or hepatic disease and with an anticipated duration of anaesthesia of at least 3 h were studied in an open, prospective, randomised clinical trial. Anaesthesia was induced with fentanyl, thiopentone, and vecuronium for facilitating endotracheal intubation. Anaesthesia was maintained with sevoflurane or enflurane, 60% nitrous oxide in oxygen, and additional doses of fentanyl. Blood samples for serum IFCs were obtained preoperatively and 2 and, if possible, 4 and 6 h after starting sevoflurane or enflurane, at the end of anaesthesia, and 1, 2, 4, 8, 12, 24, 48 and 72 h post-anaesthesia. Fluoride analysis was performed using an ion-selective electrode. Indices of renal function (serum sodium, osmolality, creatinine, urea, and uric acid, urine specific gravity, osmolality, and pH) were evaluated preoperatively, at the end of anaesthesia, and 24, 48, and 72 h post-anaesthesia. RESULTS: The duration of anaesthetic exposure was approximately 1.65 MAC-h for both inhaled anaesthetics. Peak serum IFCs were higher with sevoflurane (34.5 mumol/l) than with enflurane (19.4 mumol/l). Fluoride levels decreased more rapidly with sevoflurane: 24 h post-anaesthesia there was no difference between sevoflurane and enflurane (Fig. 1). The area under the curve (AUC) was greater with sevoflurane (688 mumol/l.h) than with enflurane (591 mumol/l.h). For both groups correlation coefficients were higher for MAC-h and AUC than for MAC-h and peak serum IFC (Figs. 2 and 3). Indices of renal function did not change in either group. DISCUSSION: In our study 1.69 MAC-h sevoflurane produced peak serum IFCs of 34.5 mumol/l. This is in accordance with the investigation of Frink et al. [4], who reported approximately 30 mumol/l after 1.4 MAC-h sevoflurane. Peak serum IFCs with sevoflurane were twice those with enflurane. Within the first 24 h post-anaesthesia, fluoride levels decreased more rapidly after sevoflurane. AUC may be more important than peak serum IFC in evaluating patients who are at risk for renal concentrating defects. In our study there was no evidence of renal dysfunction in either group.

Adult↗
PubMed1996

[Exposure of operating room personnel to anesthetic gases during ENT interventions].

During ENT surgical procedures under general anesthesia contamination of the operating room air through waste anesthetic gases seems unavoidable. A resulting chronic low-level exposure to anesthetic gases in subanesthetic concentrations (m1/m3 = ppm) may cause various negative health effects. The aim of this study was to quantify possible side effects on operating room personnel. By using a highly sensitive, direct reading instrument for determining contamination leakage from a patient's mouth and resulting concentrations in the breathing zone of the surgeon and anesthetist, levels of isoflurane and nitrous oxide were measured at 2-min intervals during 20 ENT surgical procedures performed under usual workplace conditions. Despite high concentrations of anesthetic at the mouth of each patient, personnel-related mean values remained under recommended threshold values (TLV) of 10 ppm isoflurane. A TLV of 100 ppm nitrous oxide was exceeded in 20% of the operations. Furthermore, a safe TLV for pregnant staff was 25 ppm nitrous oxide. This value was exceeded during nearly all operations (93%) for the group "surgeon". High leakages at the patient's mouth led to an undesirably high contamination of operating room personnel by nitrous oxide. Although threshold values were mostly not exceeded in available working conditions (i.e., adequate air conditioning and intubation cuff pressure control), present health and safety regulations concerning pregnant women showed that the values of nitrous oxide were still too high to allow such women to work safely in operating rooms during surgery. However, exposure to isoflurane was too slight to classify.

Adult↗
PubMed1996

A phase III, multicenter, open-label, randomized, comparative study evaluating the effect of sevoflurane versus isoflurane on the maintenance of anesthesia in adult ASA class I, II, and III inpatients.

STUDY OBJECTIVE: To compare the clinical efficacy and safety of sevoflurane and isoflurane when used for the maintenance of anesthesia in adult ASA I, II, and III inpatients undergoing surgical procedures of at least 1 hour's duration. DESIGN: Phase III, randomized, open-label clinical trial. SETTING: 12 international surgical units. PATIENTS: 555 consenting inpatients undergoing surgeries of intermediate duration. INTERVENTIONS: Subjects received either sevoflurane (n = 272) or isoflurane (n = 283) as their primary anesthetic drug, each administered in nitrous oxide (N2O) (up to 70%) and oxygen (O2) after an intravenous induction using thiopental and low-dose fentanyl. The concentration of volatile drug was kept relatively constant but some titration in response to clinical variable was permitted. Comparison of efficacy was based on observations made of the rapidly and ease of recovery from anesthesia and the frequency of untoward effects for the duration of anesthesia in the return of orientation. Safety was evaluated by monitoring adverse experiences, hematologic and non-laboratory testing, and physical assessments. In 25% of patients (all patients 171 both treatment groups at selected investigational sites), plasma inorganic fluoride concentrations were determined preoperatively, every 2 hours during maintenance, at the end of anesthesia, and at 1, 2, 4, 8, 12, 24, 48, and 72 hours postoperatively. MEASUREMENTS AND MAIN RESULTS: Emergence, response to commands, orientation, and the first request for postoperative analgesia were all more rapid following discontinuation of sevoflurane than following discontinuation of isoflurane (sevoflurane, 11.0 +/- 0.6, 12.8 +/- 0.7, 17.2 +/- 0.9, 46.1 +/- 3.0 minutes, respectively, versus isoflurane, 16.4 +/- 0.6, 18.4 +/- 0.7, 24.7 +/- 0.9, 55.4 +/- 3.2 minutes). The incidence of adverse experiences was similar for sevoflurane and isoflurane patients. Forty-eight percent of patients on the sevoflurane group had no untoward effect versus 39% in the isoflurane group. Three patients who received sevoflurane had serum inorganic fluoride levels 50 microM/I. or greater though standard tests indicated no evidence of associated renal dysfunction. CONCLUSION: Sevoflurane anesthesia, as compared with isoflurane, may be advantageous in providing a smoother clinical course with a more rapid recover.

Adult↗
PubMed1996

Evaluation of mixed venous oxygen saturation in chronic severe mitral regurgitation.

OBJECTIVE: The objective of this study was to evaluate whether chronic severe mitral regurgitation leads to an artifactual elevation of mixed venous oxygen saturation. DESIGN: Prospective study. SETTING: University hospital setting. PARTICIPANTS: Thirty patients with chronic severe mitral regurgitation undergoing surgery on the mitral valve and 25 patients without mitral regurgitation scheduled for elective coronary artery surgery. INTERVENTIONS: Blood samples were simultaneously withdrawn from the distal port and the paceport of a pulmonary artery catheter. MEASUREMENTS AND MAIN RESULTS: During steady-state-anesthesia, oxygen saturation and hemoglobin concentration were measured. There was no difference between mean oxygen saturation in blood from the pulmonary artery and the right ventricle in patients with mitral regurgitation, no matter whether large v waves were present, and in patients without mitral regurgitation. The distribution of individual differences between mixed venous and right ventricular oxygen saturation did not differ between groups. CONCLUSIONS: Because mixed venous oxygen saturation is not affected by chronic severe mitral regurgitation, it can be used in patients with mitral regurgitation just as in patients without mitral regurgitation.

Adult↗
PubMed1996

A comparison of the use of transoesophageal Doppler and thermodilution techniques for cardiac output determination.

Doppler cardiac output (CO) determination is discussed as a non-invasive alternative to CO estimation by thermodilution. This study was designed to compare the accuracy of a new transoesophageal Doppler device with the thermodilution technique. In 24 patients undergoing coronary artery bypass surgery, CO was determined simultaneously by the oesophageal Doppler (OD) and thermodilution (TD) method in triplicate for three sample episodes: after induction of anaesthesia during clinical steady-state conditions (A), after start of surgery (B), and after sternotomy (C). The agreement between ODCO and TDCO estimations was assessed by analysing the mean difference, indicating the systematic error, and analysing the distribution of differences between the two methods. The bias between ODCO and TDCO estimations was 0.38 (-0.06 to +0.81) L min-1 (mean and 95% confidence interval) for sample episode A, 0.48 (-0.11 to +1.1) L min-1 for sample episode B, and 0.69 (+0.08 to +1.3) L min-1 (P < 0.05 vs. zero) for sample episode C. Bias analysis of the log-transformed data revealed that 95% of the ODCO values differed from TDCO values by 43% below to 50% above for sample episode A, by 39% below to 95% above for sample episode B, and by 32% below to 96% above for sample episode C. Analysis of the changes in CO from sample episode A to B and from sample episode B to C, expressed as percentage values, showed a non-significant bias between the methods, but the 2 SD limits were +/-44% and +/-36% respectively. Our findings suggest that CO estimation by OD cannot replace estimation by the TD method.

Adult↗
PubMed1996

Thiopentone and propofol, but not methohexitone nor midazolam, inhibit neutrophil oxidative responses to the bacterial peptide FMLP.

The effects of different anaesthetics on the neutrophil oxidative response in vitro are compared. Neutrophils were stimulated with small amounts of the bacterial peptide N-formyl-L-methionyl-L-leucyl-phenylalanine as a physiological, receptor-dependent stimulus. A new flow cytometry-based method capable of detecting the small amounts of H2O2 generated by neutrophils in a heterogeneous all-or-none response following submaximal stimulation with N-formyl-L-methionyl-L-leucyl-phenylalanine was used. Propofol and thiopentone suppressed the respiratory burst significantly (P < 0.05 and P < 0.01) in therapeutic concentrations, while midazolam and methohexitone inhibited significantly (P < 0.01) only at concentrations greater than the therapeutic range. Impairment of the neutrophil response was primarily because of a reduction in the number of neutrophils participating in the respiratory burst and not of a proportional decrease of the fluorescence of all neutrophils.

Adult↗