Physiological responses in female rescuers during 30 minutes sustained CPR with feedback: a comparison between medicine and physical education students

OBJECTIVES

Since fatigue seems related to poorer physical fitness rather than to gender, we analyzed the physiological responses in female medicine and physical education students during a 30 minutes sustained cardiopulmonary resuscitation (CPR) sequence.

METHODS

Handgrip strength and maximal aerobic power (V02 max) determined strength and endurance. Twenty-three medicine (M) and 27 physical education (PE) female students performed 30 minutes CPR. Compression quality and ECG were continuously monitored, heart rate and non-invasive blood pressure (NIBP) every 2 minutes. Capillary pH, PcCO2, lactate, potassium and sodium bicarbonate were analyzed every 10 minutes.

RESULTS

Handgrip strength (PE 37 kg vs. M 35 kg; p<0.05) and V02 max (PE 50 ml/kg/min vs. M 44 ml/ kg/min; p<0.05) revealed a better strength and endurance in PE students. Six medicine and 1 PE student did not complete the entire 30 minutes of CPR. Percentage compressions >5 cm was comparable in both groups (PE 80%; M 79%; p=0.67). Mean heart rate during CPR was higher in the M group (148 bpm) compared to the PE group (132 bpm; p<0.05). No intergroup differences in NIBP, pH, PcCO2, potassium and sodium bicarbonate were observed. Mean lactate during CPR was higher in the M group: 3.5 mmol/l (SD 1.4) compared to the PE group: 2.5 mmol/I (SD 0.7) (p<0.05).

CONCLUSION

A high quality sustained CPR effort was well tolerated by all female rescuers. Poorer physical condition (M group) resulted in more drop out after 10 and 20 minutes and in a higher heart rate and blood lactate over time. Improving physical condition may result in less physiological strain and lower perceived exertion.

Investigation of urinary excretion of hydroxyethyl starch and dextran by uhplc-hrms in different acquisition modes

Plasma volume expanders (PVEs) such as hydroxyethyl starch (HES) and dextran are misused in sports because they can prevent dehydration and reduce haematocrit values to mask erythropoietin abuse. Endogenous hydrolysis generates multiple HES and dextran oligosaccharides which are excreted in urine. Composition of the urinary metabolic profiles of PVEs varies depending on post-administration time and can have an impact on their detectability. In this work, different mass spectrometry data acquisition modes (full scan with and without in-source collision-induced dissociation) were used to study urinary excretion profiles of HES and dextran, particularly by investigating time-dependent detectability of HES and dextran urinary oligosaccharide metabolites in post-administration samples. In-source fragmentation yielded the best results in terms of limit of detection (LOD) and detection times, whereas detection of HES and dextran metabolites in full scan mode with no in-source fragmentation is related to recent administration (< 24 hours). Urinary excretion studies showed detection windows for HES and dextran respectively of 72 and 48 hours after administration. Dextran concentrations were above the previously proposed threshold of 500 µg · mL(-1) for 12 hours. A "dilute-and-shoot" method for the detection of HES and dextran in human urine by ultra-high-pressure liquid chromatography-electrospray ionization-high resolution Orbitrap™ mass spectrometry was developed for this study. Validation of the method showed an LOD in the range of 10-500 µg · mL(-1) for the most significant HES and dextran metabolites in the different modes. The method allows retrospective data analysis and can be implemented in existing high-resolution mass spectrometry-based doping control screening analysis.

Medication in the perioperative period: stop or continue? A review

Preoperative evaluation of medication is important as part of the anesthetic plan. The aim of this manuscript is to evaluate and compare through literature review the existing evidence to support optimal perioperative medication management.

Comparison of contemporary EEG derived depth of anesthesia monitors with a 5 step validation process

During the last decennium, a growing number of depth of anesthesia monitors, extracting information from the spontaneous electroencephalogram (EEG) have been developed and commercialized. The growing interest in depth of anesthesia monitoring resulted in an intensified technological progress. Innovations on both hardware and mathematical algorithms were introduced for improving the extraction of data. Because of the abundance of monitors now commercially available, it becomes increasingly important to develop a standardized reproducible methodology for comparing depth of anesthesia monitors. In this review, the authors present a strategy to compare monitors of the hypnotic component of anesthesia, based on the available literature and their own experience with validation studies. They also discuss the level of validation of the most commonly used EEG derived depth of anesthesia monitors.

The peri-operative use of intra-articular local anesthetics: a review

Acute and chronic pain are of major concern after orthopedic surgery. The increasing trend toward day case surgery induced the development of different techniques in postoperative pain control. One commonly used strategy in pain management after knee and shoulder joint surgery is the intra-articular (IA) use of local anesthetics (LA). Recent attention has been drawn to the possible toxicity on chondrocytes of local anesthetics. The aim of this manuscript is to evaluate and compare through literature review the existing evidence on the clinical use and possible adverse effects of intra-articular injection of local anesthetics peri-operatively.

Myasthenia gravis and thymectomy: an anaesthetic approach

In this paper, we discuss the case of a 48 year old patient with newly diagnosed myasthenia gravis, who is scheduled for a thymectomy. The patient's history showed an undocumented difficult intubation, which led to the approach of an awake intubation after sevoflurane induction. We used a slightly modified non-muscle relaxant technique, allowing induction and maintanance of anesthesia under safe and excellent conditions.

Latex allergy: a challenge for anaesthetists

First reported in 1979, anaesthetists now encounter more and more patients with latex allergy. Several risk groups prone to develop this allergy have been identified. A thorough preoperative interview is necessary to detect high-risk patients. For them, the perioperative period is very dangerous because of the many possibilities of contact with latex-containing materials. There is no cure for latex allergy. Absolute avoidance of contact with latex is the only safe way to treat those who belong to a risk group or who are already allergic. The diagnosis of latex allergy must be kept in mind in every case of perioperative anaphylaxis, even if the patient does not belong to a risk group. In the future, desensitization will probably be useful in helping patients with latex allergy.

Comparative efficacy and safety of remifentanil and fentanyl in 'fast track' coronary artery bypass graft surgery: a randomized, double-blind study

This multi-centre, parallel group, randomized, double-blind study compared the efficacy and safety of high-dose remifentanil administered by continuous infusion with an intermittent bolus fentanyl regimen, when given in combination with propofol for general anaesthesia in 321 patients undergoing elective coronary artery bypass graft surgery. A significantly lower proportion of the patients who received remifentanil had responses to maximal sternal spread (the primary efficacy endpoint) compared with those who received fentanyl (11% vs 52%; P<0.001). More patients who received remifentanil responded to tracheal intubation compared with those who received fentanyl (24% vs 9%; P<0.001). However, fewer patients who received remifentanil responded to sternal skin incision (11% vs 36%; P<0.001) and sternotomy (14% vs 60%; P <0.001). Median time to extubation was longer in the subjects who received remifentanil than for those who received fentanyl (5.1 vs 4.2 h; P=0.006). There were no statistically significant differences between the two groups in the times for transfer from intensive care unit or hospital discharge but time to extubation was significantly longer in the remifentanil group. Overall, the incidence of adverse events was similar but greater in the remifentanil group with respect to shivering (P<0.049) and hypertension (P<0.001). Significantly more drug-related adverse events were reported in the remifentanil group (P=0.016). There were no drug-related adverse cardiac outcomes and no deaths from cardiac causes before hospital discharge in either treatment group.

Interventional neuroradiology--anesthetic management

Interventional Neuroradiology is a rather young department, that asks for an appropriate anesthesia management. This article highlights mainly the practical approach, with special directions for a thorough premedication, monitoring and patient positioning and extra attention to heparinisation and allergic reactions. Different anesthetic techniques are dealt with, namely conscious sedation and general anesthesia, as well as directives concerning potential complications.

Therapeutic coma or neuroprotection by anaesthetics

Some surgical patients are at an increased risk for developing cerebral ischaemia. A subset of these patients is believed to benefit from putative cerebroprotective effects of anaesthetic agents. Therefore, in this setting these drugs could have therapeutic modalities, besides their auxiliary functions to make surgery possible. However, both animal and especially human data are very disappointing. Only the barbiturates and isoflurane have an experimental record warranting further research to delineate proper indications for their use as neuroprotective agents in surgical patients.

Effect of nitric oxide predilution on inhaled nitrogen dioxide concentrations

We examined the possibility that predilution of a concentrated nitric oxide (NO) source with nitrogen, before contact with oxygen, can reduce the inspired nitrogen dioxide (NO2) concentration during administration of nitric oxide. A Manley Blease and a Siemens Servo 900 C ventilator delivered 10, 20, 40, 60 and 80 parts per million (ppm) NO using an NO source of 1000, 400 and 200 ppm. With the Manley Blease system, predilution from 1000 to 200 ppm NO reduced the inhaled NO2 concentration from 0.14 to 0.05 ppm (p < 0.01) at 10 ppm inhaled NO, and from 1.20 to 1.00 ppm (p < 0.01) at 40 ppm inhaled NO. With the Siemens Servo 900 C ventilator, inspiratory NO2 concentrations decreased from 0.21 to 0.11 ppm (p < 0.01) at 10 ppm inhaled NO, and from 1.49 to 1.16 ppm (p < 0.01) at 40 ppm NO. Predilution from 1000 to 400 ppm NO reduced the inspired NO2 concentrations by < 3% using either ventilator when the inspirated NO concentration was 80 ppm. Predilution of NO with nitrogen significantly reduced the inspired NO2 concentrations for nitric oxide concentrations between 10 and 40 ppm, but offered no clinically relevant advantage at higher NO concentrations.

Influence of anaesthesia on defibrillation threshold

Internal cardioverter-defibrillator implantation can be performed under local or general anaesthesia. Whether the technique of general anaesthesia influences the defibrillation threshold remains a matter of debate. We therefore compared, in a prospective, randomised clinical study, the effect of intravenous anaesthesia using propofol with inhalational anaesthesia using isoflurane on the defibrillation threshold in 68 patients scheduled for transvenous single-lead internal cardioverter-defibrillator implantation. Defibrillation threshold was measured at implantation and at device testing 1 week and 1 month after implantation. Patients acted as their own controls. Neither the anaesthetic technique nor the duration of anaesthesia was associated with significant changes in the defibrillation threshold. We conclude that in this group of high-risk patients, both types of anaesthesia are acceptable techniques for internal cardioverter-defibrillator implantation and testing.

In vitro evaluation of the effect of profound haemodilution with hydroxyethyl starch 6%, modified fluid gelatin 4% and dextran 40 10% on coagulation profile measured by thromboelastography

Synthetic colloids have been implicated as a cause of coagulopathy when administered in large quantities. The effect of profound haemodilution (50%) on coagulation profile was measured in vitro by thromboelastography. Blood samples were taken from 11 ASA grade 1 patients prior to induction of anaesthesia for elective surgery. Each sample was simultaneously tested in four different preparations: undiluted blood (control sample); blood diluted with hydroxyethyl starch 6%; blood diluted with modified fluid gelatin 4%; blood diluted with dextran 40 10%. There was a significant decrease in reaction time in the preparations treated with hydroxyethyl starch 6% and modified fluid gelatin 4%, reflecting activation of initial fibrin formation. A significant increase in clot formation time was noted in the hydroxyethyl starch 6%-treated preparations. There was also a significant decrease in clot formation rate and maximum amplitude in the hydroxyethyl starch 6% group. Clot formation time, clot formation rate and maximum amplitude did not change in the modified fluid gelatin 4% group. Profound haemodilution with dextran 40 10% exerted extreme effects on the measured variables, very often resulting in a straight line on the thromboelastography profile.

Limited intentional normovolemic hemodilution: ST-segment changes and use of homologous blood products in patients with left main coronary artery stenosis

OBJECTIVE

To assess and compare the effects of limited intentional normovolemic hemodilution (LINH) on ST-segment changes and to evaluate the need for homologous blood products.

DESIGN

Prospective, randomized study.

SETTING

University hospital.

PARTICIPANTS

Seventy-one patients with left main stenosis scheduled for semi-urgent coronary artery bypass grafting.

INTERVENTIONS

Patients in group A (n = 39) underwent LINH during the prebypass period until a hematocrit of 34% was obtained. Simultaneously, succinyl-linked gelatin was infused. In group B (n = 32), no hemodilution was performed. Mean arterial pressure and central venous pressure were kept as constant as possible. During the postbypass period, autologous blood was retransfused. The need for homologous blood products was noted intraoperatively and postoperatively.

MEASUREMENTS AND MAIN RESULTS

ST-segment analysis of lead II and chest lead was continuously performed in all patients. An ST-segment change was defined as a decrease from baseline of 1.0 mm (-0.1 mV). The appearance and degree of ST-segment depression were comparable in both groups (group A: 7 patients -0.1 mV, 1 patient -0.2 mV; group B: 5 patients -0.1 mV; 3 patients -0.2 mV). In group A, ST-segment depression occurred during and after the blood exchange. However, the mean duration of the ST-segment depression (group A: 33 +/- 18 minutes; group B: 20 +/- 10 minutes) was comparable between groups. In group A, a mean of 750 mL +/- 245 mL of blood was obtained. Total blood loss was significantly higher in group B (p < 0.052); 25 patients in group A (64%) and 12 patients in group B (38%) did not require homologous blood products (p < 0.03). Intraoperatively, only the need for packed red cells was greater in group B (p < 0.04). Postoperatively, the use of homologous blood products is higher than intraoperatively (p < 0.02).

CONCLUSIONS

LINH performed in patients with left main stenosis, scheduled for semi-urgent coronary bypass, is not associated with increases in frequency, degree, or duration of ST-segment changes. This procedure allowed a reduction in the number of patients who received homologous blood products.

Comparison of computer-controlled administration of propofol with two manually controlled infusion techniques

Ninety women were studied in order to compare dose requirements and quality of anaesthesia between target-controlled infusion and two manually controlled infusion schemes for propofol administration: group I received target-controlled infusion for induction (4 micrograms.ml-1 target blood concentration, increased by 2 micrograms.ml-1 after 3 min of consciousness not lost), groups II and III received an induction bolus of propofol at infusion rates of 1200 or 600 ml.h-1, respectively, until loss of consciousness. Anaesthesia was maintained with propofol target-controlled infusion in group 1 or by constant rate infusion in the other two groups. Computer simulations were used to calculate blood and effect-site propofol concentrations. Mean induction times (SD) were 78 (65)s in group I versus 51 (10)s and 62 (12)s in groups II and III, respectively (p < 0.05 between groups II and III). Mean induction doses were: 1.31 (0.44), 2.74 (0.56) and 1.77 (0.43) mg.kg-1 and mean maintenance doses were 13.4 (3.55), 9.32 (1.72) and 9.97 (1.53) mg.kg-1 h-1 in groups I, II and III, respectively (p < 0.05 between all groups). There was a lower incidence of apnoea in group I than in groups II and III. There were no significant differences between the groups in other objective parameters of anaesthetic quality studied. Computer simulations showed an "overshoot' in propofol blood and effect-site concentration with manual induction and significantly higher maintenance levels with target-controlled infusion.

Transoesophageal echocardiographic evaluation of ventricular function during transvenous defibrillator implantation

BACKGROUND

Intraoperative testing and defibrillation threshold determination may jeopardise patients, scheduled for implantation of a cardioverter-defibrillator (ICD). The purpose of this study was the assessment of the influence of consecutive defibrillation attempts on left ventricular systolic and diastolic function by means of transoesophageal echocardiography (TEE).

METHODS

Eighteen patients with malignant ventricular arrhythmias that were resistant to antiarrhythmic drugs were monitored with TEE before, during and after implantation of a cardioverter-defibrillator. Left ventricular fractional area contraction as a measure of ejection fraction was assessed before and after each defibrillation attempt. Transmitral and right upper pulmonary venous flow parameters were evaluated before and after the whole implantation procedure.

RESULTS

Adequate data were available in 14 patients during 4 consecutive attempts. No major alterations were observed in heart rate or fractional area contraction, measured at 30 s and 3 min after defibrillation. Overall, the ratio of early-to-late transmitral filling decreased significantly after the implantation procedure (from 0.91 +/- 0.12 to 0.82 +/- 0.14; P < 0.05). Systolic pulmonary venous flow velocity decreased from 0.49 +/- 0.11 to 0.41 +/- 0.10 m/s (P = 0.04); this decrease was observed in both groups. A significant increase of the atrial contraction wave (from 0.25 +/- 0.06 to 0.34 +/- 0.07 m/s; P < 0.03) was seen. Subdividing patients related to their precperative ejection fraction, a significant decrease of the early-to-late transmitral filling of the LV was revealed in patients with ejection fraction less than 35% (group 1). Also, a significantly lower systolic fraction of the pulmonary venous flow after ICD implantation in conjunction with a significantly longer diastolic flow time was shown in this patient group in comparison with patients with a preoperative ejection fraction of more than 35% (group 2).

CONCLUSION

Defibrillation threshold testing of the ICD system changes LV inflow characteristics and impedes diastolic function of the left ventricle and may thus precipitate heart failure by this mechanism. No deleterious effects of threshold testing were observed with respect to fractional area contraction nor any deterioration of LV function was found in a clinically significant amount due to consecutive defibrillation attempts.

Removal of endocardial defibrillation leads

Two patients, each with an endocardial defibrillation lead system (Endotak O62), required lead removal; one because of chronic lead infection and the second because of spurious shocks caused by lead insulation damage. Neither lead could be removed by simple traction. The defective lead was removed by a combination of catheterization techniques including a steerable ablation catheter and traction, both under general anesthesia. The lead with the insulation defect was rapidly removed with a locking stylet, suggesting that endocardial lead defibrillating leads can be removed similarly to pacemaker leads, thus avoid thoracotomy.

Comparative study of limited intentional normovolaemic haemodilution in patients with left main coronary artery stenosis

Intentional normovolaemic haemodilution is a blood saving technique which can be performed when major blood loss is expected. Severe coronary artery disease and particularly left main stenosis are considered a contraindication for intentional normovolaemic haemodilution. The effects and complications of limited intentional normovolaemic haemodilution in patients with left main coronary artery stenosis scheduled for coronary artery bypass grafting were evaluated. Patients were randomly allocated to two groups: group A (n = 15) underwent limited intentional normovolaemic haemodilution to a haematocrit of 34%; group B (n = 15), no intentional normovolaemic haemodilution was performed. In both groups succinyl-linked gelatin was used to maintain normovolaemia. Haemodynamic parameters were kept as constant as possible. In group A, a mean (SD) volume of 785 (250) ml of blood was withdrawn [range 500-1200 ml]. ST segment changes occurred on the ECG in three patients in each group. There were no statistically significant differences for frequency, maximum deflection and duration of ST-segment changes. Limited intentional normovolaemic haemodilution can be performed safely in patients with left main coronary artery stenosis. In this study it was not associated with increased frequency, severity or duration of ST-segment changes, or with arrhythmias or haemodynamic instability.

Awareness during anaesthesia for implantable cardioverter defibrillator implantation. Recall of defibrillation shocks

Implantable cardioverter defibrillator implantation is performed under general anaesthesia. This report describes awareness or recall in two of 33 patients scheduled for implantation. After induction, anaesthesia was maintained using continuous infusions of propofol and atracurium and intermittent boluses of alfentanil. Propofol was given in the same arm as the implantation side. In these two patients propofol flowed out of the bleeding central venous access. To minimise the possibility of awareness, we advise that continuous infusions should be administered intravenously on the contralateral side to the implantation and that neuromuscular blocking agent be given by intermittent bolus injections.

A new transvenous internal cardioverter-defibrillator: implantation technique, complications, and short-term follow-up

Twenty-four patients with ventricular fibrillation or sustained ventricular tachycardia underwent implantation of a new transvenous defibrillator. All patients had a device implanted without thoracotomy. High placement of a shock lead in the anonymous vein and inversion of the shock-wave polarity allowed avoidance of placement of subcutaneous patches. Implantation time decreased from 138 minutes for the first 12 patients to 82 minutes for the last 12 patients, with 4 and 11 subpectoral pockets, respectively. Three patients required a minor reintervention. No bleeding or infection occurred. One episode of pulmonary edema and one pulmonary embolism were seen in the postoperative course. No postoperative deaths were observed. During a mean follow-up period of 4.12 months, 58% of the 24 patients had symptomatic arrhythmic episodes, with shocks in 50% of the 24. Inappropriate shocks were delivered in three cases (atrial fibrillation and T-wave sensing). One episode was not terminated even with four internal shocks. One patient had ventricular fibrillation because of a sensing problem. By reprogramming of sensitivity, back-up pacing, and adjustment of drug therapy these arrhythmic complications could be prevented. Pectoral implantation of a cardioverter-defibrillator is easy and can be performed by cardiologists experienced in pacemaker implantation. Careful postoperative observation, reprogramming after the first spontaneous event, and prehospital discharge induction of ventricular fibrillation will prevent arrhythmic complications.

Haemodynamic effects of R 80122 immediately after cardiopulmonary bypass; preliminary results

R 80122 is a new short-acting phosphodiesterase type III inhibitor. In a preliminary investigation, three patients, scheduled for coronary artery bypass surgery, were given R 80122 after weaning from cardiopulmonary bypass. Two patients received 10 micrograms.kg-1.min-1 for 10 min as a loading infusion followed by a 5 micrograms.kg-1.min-1 maintenance dose. One patient received a 20 micrograms.kg-1.min-1 for 10 min loading infusion followed by a 10 micrograms.kg-1.min-1 maintenance infusion. After weaning from cardiopulmonary bypass and during the administration period, no arrhythmias or cardiac ischaemia were detected. The administration of R 80122 improved the haemodynamic profile with an increase in cardiac output, a decrease in systemic vascular resistance and a stable heart rate and mean arterial blood pressure. These preliminary results indicate that R 80122 possesses positive inotropic activity in combination with vasodilating properties.

Experience of cardioverter-defibrillators inserted without thoracotomy: evaluation of transvenously inserted intracardiac leads alone or with a subcutaneous axillary patch

OBJECTIVES

To compare the efficacy of a purely transvenous cardioverter-defibrillator (ICD) system with that of a system with a supplementary subcutaneous patch. To evaluate clinical follow up of these lead arrangements that do not require thoracotomy.

DESIGN

A simplified defibrillation protocol to test two different lead arrangements during implantation, with routine clinical follow up after implantation.

SETTING

Tertiary referral centre for treatment of arrhythmia.

PATIENTS

22 consecutive patients selected for implantation of an ICD because of life-threatening ventricular arrhythmias (ventricular fibrillation or sustained ventricular tachycardia) of whom 20 entered the test protocol.

INTERVENTION

Implantation of an ICD with transvenously inserted intracardiac leads and a subcutaneous patch and assessment of effective defibrillation followed by testing of the purely transvenous approach.

MAIN OUTCOME MEASURES

Reproducible conversion of ventricular fibrillation to sinus rhythm at a certain energy level, providing a safety margin of at least 10 J for both lead arrangements. Confirmation of efficacy during clinical follow up (mean 6 months).

RESULTS

A transvenous lead system combined with a subcutaneous axillary patch was implanted in 20/22 patients and it provided adequate and acceptable energy levels. In 10/20 tested patients a purely transvenous lead configuration provided an acceptable safety margin as well. Nine patients had clinical recurrences: all these arrhythmias were successfully converted.

CONCLUSION

A transvenous lead system was sufficient in 50% of the patients at the time of implantation. Data on long-term clinical follow up of this arrangement are not available. The approach without thoracotomy with a subcutaneous patch is feasible and effective in most patients selected for ICD treatment.

[Hemodynamic changes with sufentanil-oxygen anesthesia for open heart surgery--a comparison of patients with beta-blocking medication or without it]

We investigated hemodynamic changes in patients undergoing coronary artery bypass grafting (CABG) and valve replacement. The former had been medicated with beta-blocking agent until the morning of operative day. On the other hand, the latter received no medication. We measured systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), heart rate, and rate pressure product (RPP) at the following five points; before induction of anesthesia, immediately before intubation, immediately after intubation, one minute after skin incision and one minute after sternotomy. In both groups, SAP and DAP decreased significantly after induction; heart rate did not change during our study; and RPP decreased significantly after skin incision. There were no significant differences between the group with beta-blocking agent and the group without it. These results suggest that beta-blocking agents exert no influence in our study, and sufentanil-oxygen anesthesia produce hemodynamic stability for open heart surgery.

[Comparison of sufentanil and fentanyl anesthesia for coronary artery bypass grafting--changes in stress hormones]

We compared the changes in hemodynamics and stress hormones in 30 patients who received for CABG operation either sufentanil-oxygen or fentanyl-oxygen anesthesia. The mean doses of fentanyl and sufentanil for intubation were 1.66 +/- 0.69 mg and 0.35 +/- 0.14 mg respectively and mean total doses were 6.91 +/- 1.14 mg and 1.68 +/- 0.38 mg, or 21.4 micrograms.kg-1.hr-1 and 4.5 micrograms.kg-1.hr-1 respectively. SAP decreased significantly immediately before intubation in both groups. Immediately after intubation, a significant intergroup difference (P less than 0.05) was noted. The changes in DAP and MAP were almost similar to those of SAP. This study demonstrates that sufentanil-oxygen anesthesia gave more stable hemodynamic parameters before and after intubation. Especially no significant changes in heart rate occurred immediately after intubation and with CABG operation, thus preventing the increase in rate pressure product during procedure. Sufentanil anesthesia did attenuate more effectively the stress hormones release than high dose fentanyl anesthesia, but neither sufentanil nor fentanyl anesthesia could prevent the increases in these hormones postoperatively.

Anaesthetic management of systemic mastocytosis

Systemic mastocytosis is an uncommon disorder of mast cell proliferation in connective tissues. Mast cell degranulation may occur on exposure to various stimuli and drugs. The release of histamine, heparin and vasoactive substances such as prostaglandin D2 may cause severe hypotension and other anaphylactoid manifestations. Anaesthetic management should include perioperative stabilization of mast cells and avoidance of the use of histamine-releasing drugs. Intradermal skin testing is useful in predicting the sensitivity to drugs that may be used during anaesthesia. We present a patient with systemic mastocytosis who underwent uneventful cholecystectomy.

[A comparison of hemodynamic changes with sufentanil-O2 and fentanyl-O2 anesthesia for coronary bypass grafting]

Hemodynamic changes were investigated in twenty patients undergoing coronary artery bypass grafting. Thirteen patients received sufentanil-O2 anesthesia and seven patients had fentanyl-O2 anesthesia. Systolic, diastolic, as well as mean arterial blood pressures, heart rate and rate pressure product (RPP) were measured before and after intubation, one minute after skin incision, and one minute after sternotomy. The sufentanil group received 3-5 micrograms.kg-1 of sufentanil for induction and a continuous infusion of 2.5-5.0 micrograms.kg-1.hour-1. The fentanyl group received 10 to 20 micrograms.kg-1 for induction and a continuous infusion of 12.5 micrograms.kg-1.hour-1. In sufentanil group, a decrease of systolic as well as mean arterial pressure, heart rate and RPP was observed following induction. These results showed effective blocking of the sympathetic reflex by sufentanil. In the fentanyl group, immediately after intubation, an increase in systolic pressure, mean pressure, heart rate and RPP was observed. Particularly RPP increased to more than 12000 at this moment. Diastolic pressure was not significantly changed in each group. Stable hemodynamic parameters with no ST-T change were noticed during surgical procedure in each group. We conclude that sufentanil is a superior narcotic agent than fentanyl for the patients undergoing CABG, and it effectively blocks sympathetic reflex activity.

EEG and SEMG monitoring during induction and maintenance of anesthesia with propofol

Propofol has been used as IV induction (2 mg/kg) and maintenance agent (150 micrograms/kg/min and 100 micrograms/kg/min after 30 min), combined with N2O/O2 in 16 premedicated (atropine 0.5 mg, Thalamonal 2 ml IM) and mechanically ventilated patients, having ear surgery or arthroscopy. Cranial biopotentials were analysed by 2 different techniques: 1. The Anesthesia and Brain Activity Monitor (ABM Datex) providing the zero crossing frequency (ZXF) as a value for the mean frequency of the EEG signal during a considered time interval, the mean integrated voltage (MIV) as a mean value of the amplitude of the same EEG signal and the spontaneous electromyography of the frontal muscle (SEMG). 2. The EEG trend monitor (rough signal, spectral analysis (S.A.), procentual display). The EEG changes, recorded during propofol anesthesia, are comparable with both techniques. Induction is characterised by a decrease in ZXF, caused by a procentual increase in the low frequency bands (the delta band represents more than 80% of the total power). During the perfusion period an increase in the power of the alpha band (10% to 40%) and a decrease in the delta band is noticed. The ZXF regains its original value. At the end of the procedure the ZXF increases (beta band to more than 30%). A correlation was looked for between the EEG changes and the propofol blood concentrations. The higher the propofol blood concentrations, the more pronounced the low frequency bands. The appearance of beta waves or a ZXF greater than 10 Hz indicates pending arrousal.

Propofol for arthroscopy in outpatients. Comparison of three anaesthetic techniques

Sixty unpremedicated adult patients, undergoing arthroscopy, received propofol 2 mg kg-1 for induction of anaesthesia, before random allocation to three groups receiving one of the following: a continuous infusion of propofol supplemented with nitrous oxide in oxygen (group I); isoflurane and nitrous oxide in oxygen (group II); a continuous infusion of propofol in combination with repeated bolus doses of alfentanil (group III). The results showed no major differences in cardiovascular variables between the groups. Ventilation rate was highest in group II. Early recovery was less smooth and showed slight impairment in group III compared with the other groups. The data suggest that induction of anaesthesia with propofol followed by maintenance with isoflurane or continuous infusion of propofol is preferable for this procedure.

Effect of propofol on elevated intracranial pressure. Preliminary results

The effects of a bolus injection of propofol on mean intracranial pressure were studied in six adult, comatose patients who had severe head injuries. Propofol 2 mg/kg was given intravenously over 90 seconds when the mean intracranial pressure reached or exceeded 25 mmHg. Arterial blood gas values, heart rate and central venous pressure remained stable at all measurements. Arterial blood pressure decreased statistically significantly (p less than 0.05) within one minute after propofol administration. The mean (SEM) intracranial pressure decreased statistically significantly (p less than 0.05) at 30 seconds and at 1 and 2 minutes, from 25 (3) to 11 (4) mmHg. The cerebral perfusion pressure decreased statistically significantly from 92 (8) mmHg at all measurements (p less than 0.05). The lowest value at 3 minutes was 50 (7) mmHg but in four patients at that time the perfusion pressure was below 50 mmHg.

Propofol combined with nitrous oxide-oxygen for induction and maintenance of anaesthesia

After a bolus of 2 mg/kg, propofol was given by continuous infusion (150 micrograms/kg/minute for 30 minutes and then 100 micrograms/kg/minute) supplemented with nitrous oxide for anaesthesia during ear surgery in 12 patients. Cardiovascular changes were not significant except for a decrease in heart rate after 60 minutes. Acid-base balance was unaffected by the amount of fatty emulsion. Cortisol levels showed a nonsignificant decrease during the prolonged administration of propofol but had recovered completely by one hour following anaesthesia. Mean blood concentrations of propofol were 10.5 micrograms/ml (SEM 1.2) at the onset of unconsciousness, between 3.4 and 4.5 micrograms/ml during continuous infusion and 2.9 micrograms/ml (SEM 0.3) on awakening. Patients opened their eyes 6 minutes (SEM 1) after discontinuation of the infusion, and were responsive at 7.5 minutes (SEM 0.5), which suggests that propofol infusion can be used safely for surgery of 2 hours' duration.

Anesthesia for foreign bodies in the tracheo-bronchial tree in children

The authors present the anesthetic and ventilation techniques, used in 106 children, who were suspected of foreign body aspiration in the respiratory tract. In 62 children a foreign body was found. The youngest child was 8 months old and the oldest 13 years, with an age distribution peak in the 1 to 2 years age group. A predominance for the male sex (60%) was present. Foreign bodies of organic nature were found most frequently (80%), 39 of them consisting of peanuts. The bronchi were involved more often than the trachea and the foreign body was located more frequently at the right bronchus (38 pt). The children were ventilated initially with an intermittent oxygen jet injection technique, using a home made apparatus, but since 1978 with HFPPV, using the AGA Bronchovent. Induction of anesthesia was done with halothane and maintenance with etomidate infusion (10-20 micrograms/kg/min.) or thiopental increments (2 to 3 mg/kg). The technique so far used, proved to be satisfactory, specially since HFPPV is used. Few complications occurred. One child died during the bronchoscopic procedure and in an other child a tracheostomy had to be performed for extraction of the foreign body.