Summary

Background and objective: We evaluated the validity of a newly developed pulse dye densitometer for indigo carmine for measuring cardiac output and circulating blood volume.

Methods: Measurements of cardiac output and circulating blood volume were performed with the indigo carmine densitometer during normovolaemia, hypovolaemia and hypervolaemia in nine mongrel dogs under general anaesthesia. The validity was evaluated by comparison of the values of cardiac output and circulating blood volume obtained by the thermodilution technique and the 51Cr-labelled red blood cell method, respectively. We also examined indigo carmine removal by continuous veno-venous haemofiltration after indigo carmine injection.

Results: There was good agreement between dye densitometer- and thermodilution-derived cardiac output (r = 0.885, P < 0.001). The bias and limits of agreement of these values were 0.09 and ± 1.07L min−1 (2 SD, n = 22), respectively. The dye-densitometer-derived circulating blood volume was greater than that of the 51Cr-labelled red blood cell method, and both values showed weak agreement (r = 0.587, P < 0.027). The sieving coefficient of indigo carmine through continuous veno-venous haemofiltration was 0.34 ± 0.06.

Conclusions: These data indicate that indigo carmine densitometry is a reliable method for cardiac output determination, but it overestimates circulating blood volume, probably due to the transition of indigo carmine into the extravascular space in the systemic circulation.

Megaoesophagus resulting from achalasia is a rare but serious cause of airway obstruction. The exact aetiology remains unclear. Although 29 cases have previously been reported, the potential need for urgent treatment has not been suf®ciently emphasized. Some forms of treatment with drugs or decompression with a ®ne tube have been advocated but emergency tracheal intubation may become necessary. A 90-year-old lady had a bolus of food lodged in her oesophagus but with no respiratory symptoms.

A 90-year-old lady had a bolus of food lodged in her oesophagus but with no respiratory symptoms. The bolus was removed under anaesthesia. Six weeks later she suffered similar symptoms after eating but developed severe airway obstruction over 10 min. Emergency intubation of the trachea was necessary before removing the food bolus under general anaesthesia. This case demonstrates the urgency with which these patients may need to be treated. The condition can rapidly worsen due to swallowing of air and saliva.

It is assumed that diabetic patients with uraemia have more complications at renal transplantation than those who are not diabetic. We compared the preoperative ECGs, and invasive perioperative haemodynamic and oxygenation parameters in 15 diabetic and 15 non-diabetic uraemic patients undergoing renal transplantation. The number of patients with increased QT dispersion in the ECG was higher in diabetic than in non-diabetic patients (P < 0.05). Before anaesthesia, heart rate and mean arterial pressure were higher (P <0.05) in the diabetic than in the non-diabetic group. After preanaesthetic volume loading all patients showed a hyperdynamic circulation, which subsided during anaesthesia. However, stroke volume index remained unchanged. Four patients in the diabetic group and six in the non-diabetic group needed additional oxygen therapy after surgery. No cardiac dysrhythmias were noted. However, the increased QT dispersion in diabetic patients calls for an adequate perioperative ECG monitoring for dysrhythmias. The diabetic and non-diabetic uraemic patients performed equally well at renal transplantation. In conclusion, renal transplantation for diabetics is justified.

The haemodynamic effects of anaesthesia with gamma-hydroxybutyrate (GHB)/sufentanil for elective coronary artery bypass grafting (CABG) were investigated and compared in patients with unimpaired left ventricular function (ejection fraction ≥45%, left ventricular end diastolic pressure ≤16 mmHg) and patients with impaired left ventricular function. In 38 consecutive patients scheduled for CABG (21 with unimpaired and 17 with impaired left ventricular function), anaesthesia was induced with etomidate, sufentanil and pancuronium. After tracheal intubation, the lungs were normoventilated (end tidal Pco2 4.9−5.6 kPa) with an oxygen-air mixture (Fio2 0.5). Total intravenous anaesthesia was maintained with GHB (20 mg kg−1 h−1after a ‘priming dose’ of 40 mg kg−1) and sufentanil (2 μg kg−1 h−1). Haemodynamic measurements were made after induction of anaesthesia and at various times in the prebypass period. Patients in both groups showed similar haemodynamic trends. Mean arterial pressure showed a maximum reduction of 10%, whereas heart rate and right- and left-sided filling pressures remained unchanged within the groups after the induction of anaesthesia. Cardiac index remained unchanged in both groups, although values differed between the groups. A total of 14 out of 21 patients (67%) with unimpaired and 10 out of 17 patients (59%) with impaired ventricular function required supplementary administration of opioids to control temporary hypertension after sternotomy. No episodes of myocardial ischaemia were detected during the study period using ST segment analysis (leads II and V5). The results of this study suggest that GHB provides adequate haemodynamic conditions in the prebypass period and may be a suitable agent for TIVA also in patients with impaired left ventricular function undergoing CABG.

Summary

Sepsis is associated with a profound intravascular fluid deficit due to vasodilatation, venous pooling and capillary leakage. Fluid therapy is aimed at restoration of intravascular volume status, haemodynamic stability and organ perfusion. Circulatory stability following fluid resuscitation is usually achieved in the septic patient at the expense of tissue oedema formation that may significantly influence vital organ function. The type of fluid therapy, crystalloid or colloid, in sepsis with capillary leakage remains an area of intensive and controversial discussion. The current understanding of the physiology of increased microvascular permeability in health and sepsis is incomplete. Furthermore, there is a lack of appropriate clinical study end-points for fluid resuscitation. This review considers critically the clinical and experimental data analysing the assessment of capillary leakage in sepsis and investigating the effects of different fluid types on increased microvascular permeability in sepsis.

Prolongation of the QT interval may produce potentially hazardous arrhythmias. The effects of midazolam or propofol, followed by suxamethonium on the QT interval have been investigated. Thirty patients, ASA I or II, without cardiovascular disease, electrolyte abnormalities or receiving any medication were studied. All patients were premedicated with midazolam 0.08 mg kg−1 i.m., 30–60 min prior to surgery. Anaesthesia was induced with either midazolam 0.4 mg kg−1 i.v., (15 patients) or propofol 1 mg kg−1 i.v. bolus, followed by a continuous infusion (15 patients). ECG, heart rate and arterial pressure were measured before induction of anaesthesia and at 1 and 3 min after the bolus of midazolam or propofol. Further recordings were obtained at 1 and 3 min after a bolus of suxamethonium 1.5 mg kg−1 i.v. and also immediately after tracheal intubation and 1 min later. Neither midazolam nor propofol had any significant effect on QTc interval. Prolongation of QTc was observed in both groups after suxamethonium and this was further prolonged following intubation. Heart rate and arterial pressure were also increased significantly in both groups following intubation.

As is often the case in medicine, the risk to benefit ratio of blood transfusion requires careful examination. The decision to transfuse a patient cannot be based only on the haemoglobin or the haematocrit concentration. In a given clinical situation, tolerance to anaemia will depend on the ability of the patient to recruit his compensatory mechanisms in accordance with his metabolic demand. Maintenance of circulating volume is of paramount importance. In the absence of a universal transfusion trigger, decision to transfuse a patient with an haemoglobin concentration between 7.0 and 10.0 g dL−1 depends primarily on clinical judgement. With the exception of emergency situations, blood transfusion will be realized on a unit-by-unit basis, and the efficacy of treatment should be evaluated after each transfused unit.

Background and objective: The aim of this prospective, randomized study was to compare the preparation and discharge times, the side-effects and patient satisfaction after gynaecological outpatient procedures performed using either spinal block or total intravenous anaesthesia with propofol and remifentanil.

Methods: With Ethics Committee approval and written informed consent, 40 healthy females scheduled for hysteroscopic ablation of endometrial neoplasm were randomly allocated to receive either a spinal block with bupivacaine 0.5% hyperbaric solution 10 mg (n = 20) or total intravenous anaesthesia with propofol and remifentanil (n = 20). Preparation and discharge times, as well as occurrence of untoward events and anaesthesiarelated costs, were recorded.

Results: The median (range) preparation time was 7 (7–10) min with general anaesthesia, and 11 (7–21) min with spinal block (P = 0.00005). No differences in discharge time from the postanaesthesia care unit and incidence of hypotension or bradycardia, or both, were reported between the two groups. Hospital discharge times were 156 (101–345) min after general anaesthesia and 296 (195–720) min after spinal anaesthesia (P = 0.0005). Acceptance of the anaesthesia technique was better after general (100%) than after spinal anaesthesia (75%) (P = 0.04). No differences in total costs were reported between spinal block (€155 (€117–€224)) and propofol-remifentanil general anaesthesia (€143 (€124–€203) (P = 0.125)).

Conclusions: Accurate titration of short-acting intravenous anaesthetic drugs such as propofol and remifentanil results in shorter preparation times and earlier home discharge after outpatient gynaecological procedures compared with spinal anaesthesia with hyperbaric bupivacaine 10 mg, with better patient acceptance and no increased costs.

Background and aim This study determines whether epidural fentanyl given before incision decreases the requirements for opioid analgesia postoperatively, compared with the same dose of epidural fentanyl given after the surgery.

Methods Forty patients scheduled to undergo elective abdominal surgery were randomly allocated between two groups according to the time of administered of fentanyl. None of the patients in either group received premedica-tion. Prior to induction of general anaesthesia an epidural catheter was inserted at the L2–3 interspace and flushed with 0.9% NaCI. Patients then received 100μg fentanyl in 10mL 0.9% NaCI through this catheter either 15min before awaking at the end of the operation (group I), or else the same dose given at an estimated time of 15 min before the start of surgery (group II). Postoperative analgesia consisted of patient-controlled intravenous fentanyl. The amount of fentanyl used by the patients was noted at 2, 4, 8, 12 and 24 h after surgery. Pain scores and sedation scores were assessed at 0, 2, 4, 8, 12 and 24 h postoperatively.

Results The consumption of fentanyl was similar in both groups in all studied periods postoperatively. The mean pain score was lower for patients in group I than group II immediately after operation. There were no statistically significant differences between the mean pain scores of groups at 2, 4, 8, 12 and 24 h after operation. Mean sedation scores were similar in both groups at all times postoperatively.

Conclusion This study showed that the dose of fentanyl administered epidurally prior to surgical incision did not produce any clinically useful pre-emptive analgesic effect.

Summary

Background and objective: μ-agonistic opioids cause concentration-dependent hypoventilation and increased irregularity of breathing. The aim was to quantify opioid-induced irregularity of breathing and to investigate its time-course during and after an opioid infusion, and its ability to predict the severity of respiratory depression.

Methods: Twenty-three patients breathing spontaneously via a continuous positive airway pressure (CPAP) mask received an intravenous (i.v.) infusion of alfentanil (2.3 μg kg−1 min−1, 14 patients) or pirinitramide (piritramide) (17.9 μg kg−1 min−1, nine patients) until either a cumulative dose of 70 μg kg−1 for alfentanil or 500 μg kg−1 for pirinitramide had been achieved or the infusion had to be stopped for safety reasons. Tidal volumes (VT) and minute ventilation were measured with an anaesthesia workstation. For every 20 breaths, the quartile coefficient was calculated (Qeff20VT).

Results: Both the decrease of minute volume and the increase of Qeff20VT during and after opioid infusion were highly significant (P < 0.001, ANOVA). Patients in which the alfentanil infusion had to be terminated prematurely had lower minute volumes (P = 0.002, t-test) and higher Qeff20VT (P = 0.034, t-test) than those who received the complete dose. Changes in the regularity of breathing measured as Qeff20VT parallel those of minute ventilation during and after opioid infusion.

Conclusions: Opioids cause a more complicated disturbance of the control of respiration than a mere resetting to higher PCO2. Furthermore, Qeff20VT appears to predict the severity of opioid-induced respiratory depression.

Both the numbers of children undergoing day case surgery and the type of procedures performed in this way are increasing. This expansion will only be beneficial if anaesthesia and surgery are provided with minimal postoperative morbidity e.g. postoperative delirium or nausea and vomiting. The choice of anaesthetic technique is considered critical to optimizing the service provided to patients and for this reason much research has addressed this question. This review considers the effect of anaesthetic technique on postoperative outcome in paediatric day case surgery. The outcome measures reviewed by this article are induction of anaesthesia, effects on the cardiovascular system, recovery from anaesthesia and postoperative nausea and vomiting. In each section both quantitative and qualitative outcome measures are discussed. Comparisons are made between sevoflurane and halothane, sevoflurane and propofol, propofol and halothane, desflurane and halothane and the presence or absence of nitrous oxide.

Summary

Background and objective: The development of acute renal failure (ARF) in critically ill patients is associated with an increase in hospital mortality. Recently, it was shown that starting renal replacement therapy early and using high-filtrate flow rates can improve the outcome, but this could not be confirmed in later investigations. Studying selected patient subgroups could provide a useful basis for patient selection in future trials evaluating the outcome of renal replacement therapies. We, therefore, investigated the impact of the underlying disease on the outcome of patients with ARF.

Methods: We retrospectively analysed 306 patients with ARF who were treated with renal replacement therapy. Patients were classified according to six initial diagnosis groups: haemorrhagic shock, post-cardiac surgery, post-liver transplantation, trauma, severe sepsis and miscellaneous. Univariate and multivariate multiple logistic regression analysis was used to determine which factors influenced the outcome.

Results: Underlying disease proved to be the only independent risk factor for mortality that was present at intensive care unit (ICU) admission (P = 0.047). Patients with severe sepsis had a significantly higher mortality rate (68%) than ARF patients as a whole (51%) (P = 0.02). Length of stay in the ICU, the use of catecholamines, the delay before ARF onset, and the correlation between APACHE II score and ICU length of stay proved to be additional independent predictors of outcome.

Conclusions: Patient selection and subgroup definition according to the underlying disease could augment the usefulness of future trials evaluating the outcome of ARF.

Serious neurological complications of abdominal aortic vascular surgery are rare but devastating for all involved. When epidural blockade is part of the anaesthetic technique such compliscations may be attributed to needles, catheters or drugs. We present a patient who developed paraplegia following an elective abdominal aortic aneurysm repair. Continuous epidural blockade was part of the anaesthetic technique and postoperative analgesia. In this case the spinal cord damage was explained by ischaemia caused by the aortic surgery. This event has made us aware of a rare complication associated with abdominal aortic surgery and highlighted safety aspects of epidural anaesthesia in such patients.

Summary

Background and objective: We have evaluated the effects of propofol and its relationship with K+ channels on human isolated umbilical vessels. Methods: Umbilical vessel rings were suspended in isolated organ baths containing Krebs–Ringer solution. In the first series of experiments the effect of propofol (10−9–10−4M) was examined in a concentration-dependent manner on umbilical vessels precontracted with KCl (60 mmol). In the second series, these effects were studied in the presence of tetraethylammonium. Results: A mild contraction was produced by low dose propofol in both precontracted umbilical artery and umbilical vein segments. 10−4M propofol caused significant relaxation in both umbilical artery and umbilical vein. The relaxation response was significantly reduced by the addition of 10−1 M tetraethylammonium. Conclusion: These results suggested that the responses of propofol on KCl-induced contractions of both umbilical artery and vein were dose dependent, and this effect involved Ca2+ activated K+ channels.

Summary

Background and objectives: Apoptosis occurs after thermal injury and may result from either ischaemic intestinal insult or inflammatory mediators released after burn injury. The aim of the study was to investigate the effects of propofol and ketamine on gut epithelium apoptosis after burn injury. Methods: Sixty male Wistar Albino rats were randomly assigned into four groups. Anaesthesia was induced and maintained with propofol in Groups 1 and 2, and ketamine in Groups 3 and 4 over 12 h. Groups 2 and 4 received 30% total body surface area burn. Groups 1 and 3 had no burn injury. Mean arterial pressure was maintained within 10% of baseline levels in all animals. At 12 h postburn, animals were sacrificed and tissue samples were taken from small intestine for determination of lipid peroxidation, apoptosis and proliferation. Also blood samples were taken for measurement of serum tumor necrosis factor-alpha (TNF-α) levels. Results: Ileal malondialdehyde (MDA) concentration (extent of lipid peroxidation) increased significantly in Group 4 (112.4 ± 10.2 nmol g−1) compared to Group 3 (48.4 ± 5.6 nmol g−1) and Group 2 (59.8 ± 3.2 nmol g−1). The mean TNF-α level in Group 4 (118.9 ± 10.5 pg mL−1) at 12 h postburn was significantly higher than the mean in Group 2 (56.4 ± 4.3 pg mL−1). Group 4 had the highest mean TUNEL index (terminal deoxyuridine nick-end labelling – an index of extent of apoptosis) of all the groups (265/10). Also the mean TUNEL index value in Group 2 (53/10) was higher than that of Group 1 (3/10) and Group 3 (5/10). The proliferating cell nuclear antigen index (extent of proliferation) remained unchanged among groups. Conclusions: Propofol could offer a protection against apoptosis of enterocytes with a stable tissue MDA and serum TNF-α level compared to ketamine anaesthesia in an animal model of burn injury.