Development and validation of a comprehensive model to predict complications after hepatectomy

OBJECTIVE: Despite advances in perioperative care, hepatectomy remains associated with morbidity rates of up to 40%. Currently, available nomograms for predicting severe post-hepatectomy complications do not include early postoperative data. This retrospective observational study aimed to determine whether the parameters routinely measured in patients admitted to the Intensive Care Unit (ICU) after hepatectomy could represent risk factors for severe morbidity and to propose a nomogram scoring system to predict severe postoperative complications. PATIENTS AND METHODS: 411 adult patients who underwent elective hepatectomy at a high-volume tertiary care center for hepatic surgery from December 2016 to June 2022 were enrolled. The primary outcome was the assessment of predictors of 30-day severe postoperative complications following hepatectomy, defined as Clavien-Dindo grade 3a or higher. As a secondary outcome, we aimed to develop an easy-to-use scoring system to estimate the risk of severe postoperative complications. RESULTS: Severe complications occurred in 78 patients (19%). The final model included body mass index, preoperative bilirubin level, and ICU data (i.e., pH, lactate clearance, arterial lactate concentration 12 hours after ICU admission, need for packed red blood cell transfusions, and length of stay). Notably, the latter three variables were proven to be independent predictors of the outcomes. The model showed an overall good fit (C-index=0.754, corrected Dxy=0.692). A calibration plot using bootstrap internal validity resampling confirmed the stability of the model (mean absolute error=0.017, root mean square error of approximation=0.00051). CONCLUSIONS: We developed an accurate and practical scoring system based on preoperative and early postoperative data to predict poor outcomes after hepatectomy. Further external validation on larger series could lead to the integration of such a tool in the routine clinical practice to support patients' management and early warning during ICU stay.

Graphical Abstract

https://www.europeanreview.org/wp/wp-content/uploads/Graphical-Abstract-NEW-2.pdf.

High intraoperative blood product requirements in liver transplantation: risk factors and impact on the outcome

OBJECTIVE

Liver transplantation (LT) is associated with a significant bleeding and the high transfusion requirements (HTR) negatively affect the outcome of LT patients. Our primary aim was to identify potential predictors of intraoperative transfusion requirements. Secondarily, we investigated, the effect of transfusion requirements on different clinical outcomes, including short-term morbidity and mortality.

PATIENTS AND METHODS

Data collected in 219 adult LT from a deceased donor, grouped according to HTR (defined as the need of 5 or more red blood cell units), were compared.

RESULTS

We found that previous portal vein thromboses (p=0.0156), hemoglobin (Hb) (p<0.0001), International Normalized Ratio (INR) (p=0.0010) at transplant and veno-venous by-pass (p=0.0048) independently predicted HTR. HTR was always associated with poorer outcomes, including higher simplified acute physiology II score at Intensive Care Unit admission (p=0.0005), higher rates of pulmonary infections (p=0.0015) and early rejection (p=0.0176), longer requirement of mechanical ventilation, (p<0.0001), more frequent need for hemodialysis after transplantation (p=0.0036), overall survival (p=0.0010) and rate of day-90 survival (p=0.0016).

CONCLUSIONS

This study identified specific risk factors for HTR and confirmed the negative impact exerted by HTR on clinical outcomes, including recipient survival. Prospective investigations are worth to assess whether correcting pre-transplant Hb and INR levels may effectively reduce blood product need and improve prognosis.

Effects of remifentanil on human C20 microglial pro-inflammatory activation

OBJECTIVE

Remifentanil (RF) is a potent short-acting μ-opioid receptor agonist. Although preferred for its unique pharmacokinetics, the clinical use may be limited by hyperalgesia. Preclinical studies have shown a potential role of microglia on the development of hyperalgesia, with limited and conflicting evidence on RF. Considering the role of microglia in the initiation and maintenance of brain inflammation and their different responses among species, we aimed at characterizing RF effects on human adult microglia in vitro.

MATERIALS AND METHODS

RF was tested at clinically relevant concentrations on the human microglial C20 cell line. Expression and release of interleukin-6 (IL-6) and brain derived neurotrophic factor (BDNF) were assessed under basal and inflammatory conditions.

RESULTS

The expression and secretion of IL-6 significantly increased in C20 cells in response to pro-inflammatory cytokines. RF did not modify this response neither under basal nor under inflammatory conditions. No toxicity due to RF was detected. The drug displayed a modest stimulatory effect on the production of BDNF.

CONCLUSIONS

Although RF does not exert direct pro-inflammatory actions on human adult microglia, its effects on BDNF, a crucial mediator of pain transmission, suggest a possible role on neuroinflammation and pain perception.

Hyperthermic intrathoracic chemotherapy combined to iterative cytoreductive surgery to treat a pleural carcinosis from psudomixoma peritonei. A case report

Pseudomyxoma peritonei (PMP) is an uncommon disease with locally-invasive attitude. Intrathoracic spread is rarely reported and its management extremely challenging. A 51-year-old Caucasian female presented with left pleural carcinosis 9-months after two sequential abdominal surgical procedures combined with HIPEC for low-grade PMP. Cytoreductive surgery (pleurectomy/decortication) was followed by 60-minutes hyperthermic intrathoracic chemotherapy mitomycin-C (215 mg/m2) infusing at same temperature (42°C) and intrapleural pression (2-4 mmH2O). No intra-operative complication occurred, the post-op stay was uneventful and no sign of recurrence was observed 9-months after surgery. Cytoreductive thoracic surgery and hyperthermic chemotherapy (HITHOC) could be a feasible therapeutic option in very selected cases.

Psychological, emotional and social impairments are associated with adherence and healthcare spending in type 2 diabetic patients: an observational study

OBJECTIVE

The aim of the present study was to assess the association among anxiety, depression, stress, social support and emotional abilities with adherence and healthcare spending in type 2 diabetic patients.

PATIENTS AND METHODS

Sixty-four patients were enrolled and completed: Interpersonal Processes of Care (IPC), 20-item Toronto Alexithymia Scale (TAS-20), Rapid Stress Assessment Scale (RSAS), Morisky Medication Adherence Scale (MMAS-4), International Physical Activity Questionnaire (IPAQ)-Short Form and a socio-anamnestic questionnaire regarding also the healthcare spending.

RESULTS

Mathematical linear regressions models were performed showing the predictive effects of: anxiety and social support scores (RSAS) on adherence levels (respectively p =. 019; p =. 016); adherence levels on anxiolytic use (p =.04); aggressiveness scores (RSAS) on the number of general check-ups (p =.031); TAS-20 and physician-patient communication (IPC) on the number of hospitalization days (respectively p=.001; p=.008); physician patient decision making (IPC) scores on physical activity (IPAQ) levels (p=.025); physical activity (IPAQ) on the number of medical examinations (p=.039).

CONCLUSIONS

An association among psychosocial impairment, adherence and healthcare spending was found. Future studies should investigate the effect of a brief psychological intervention in increasing adherence levels and reducing the healthcare spending in this clinical population.

Socio-emotional ability, temperament and coping strategies associated with different use of Internet in Internet addiction

OBJECTIVE

The aim of the present study was to compare socio-emotional patterns, temperamental traits, and coping strategies, between a group of Internet addiction (IA) patients and a control group.

PATIENTS AND METHODS

Twenty-five IA patients and twenty-six healthy matched subjects were tested on IA, temperament, coping strategies, alexithymia and attachment dimensions. Participants reported their prevalent Internet use (online pornography, social networks, online games).

RESULTS

The IA patients using Internet for gaming online showed a greater attitude to novelty seeking and a lower tendency to use socio-emotional support and self-distraction compared to patients using Internet for social networking. Moreover, they showed a lower level of acceptance than patients using Internet for pornography. In the control group, the participants using Internet for online gaming showed higher levels of IA, emotional impairments and social alienation compared to social-networks and pornography users.

CONCLUSIONS

Findings showed a higher psychological impairment in gaming online users compared to social networking and online pornography users.

Role of surgical setting and patients-related factors in predicting the occurrence of postoperative pulmonary complications after abdominal surgery

OBJECTIVE

The aim of this retrospective study was to evaluate the role of surgical setting (urgent vs. elective) and approach (open vs. laparoscopic) in affecting postoperative pulmonary complications (PPCs) prevalence in patients undergoing abdominal surgery.

PATIENTS AND METHODS

After local Ethical Committee approval, 409 patients who had undergone abdominal surgery between January and December 2014 were included in the final analysis. PPCs were defined as the development of one of the following new findings: respiratory failure, pulmonary infection, aspiration pneumonia, pleural effusion, pneumothorax, atelectasis on chest X-ray, bronchospasm or un-planned urgent re-intubation.

RESULTS

PPCs prevalence was greater in urgent (33%) vs. elective setting (7%) (χ2 with Yates correction: 44; p=0.0001) and in open (6%) vs. laparoscopic approach (1.9%) (χ2 with Yates correction: 12; p=0.0006). PPCs occurrence was positively correlated with in-hospital mortality (Biserial Correlation r=0.37; p=0.0001). Logistic regression showed that urgent setting (p=0.000), Ariscat (Assess Respiratory Risk in Surgical Patients in Catalonia) score (p=0.004), and age (p=0.01) were predictors of PPCs. A cut-off of 23 for Ariscat score was also identified as determining factor for PPCs occurrence with 94% sensitivity and 29% specificity.

CONCLUSIONS

Patients undergoing abdominal surgery in an urgent setting were exposed to a higher risk of PPCs compared to patients scheduled for elective procedures. Ariscat score fitted with PPCs prevalence and older patients were exposed to a higher risk of PPCs. Prospective studies are needed to confirm these results.

Relationship between blood remifentanil concentration and stress hormone levels during pneumoperitoneum in patients undergoing laparoscopic cholecystectomy

OBJECTIVE

The effect of remifentanil on stress response to surgery is unclear. However, there are not clinical studies investigating the relationship between blood remifentanil concentrations and stress hormones. Therefore, the aim of the present study was to assess the association between blood remifentanil concentrations measured after pneumoperitoneum and cortisol (CORT) or prolactin (PRL) ratio (intraoperative/preoperative value), in patients undergoing laparoscopic cholecystectomy.

PATIENTS AND METHODS

Patients did not receive any pre-anesthetic medication. Anesthesia induction was standardized. Anesthesia maintenance was performed with inhaled sevoflurane at age-adjusted 1.0 minimum alveolar concentration and intravenous remifentanil at infusion rate ranging from 0.1 to 0.4 mcg/kg/min. Blood samples were withdrawn before anesthesia induction and 5 min after achieving a pneumoperitoneum pressure of 12 mmHg. Correlation analyses were performed to evaluate the relationship between measured blood remifentanil concentrations, CORT or PRL ratio (intraoperative/preoperative value) and remifentanil dose delivered by the pump.

RESULTS

A significant inverse correlation was found between CORT ratio and measured blood remifentanil concentration (p=0.03) or planned remifentanil dose (p=0.04). No correlations were found between blood remifentanil concentration and PRL ratio (p=0.83).

CONCLUSIONS

Our data suggest that the CORT response to surgical stress is more efficiently counteracted by increased blood remifentanil concentration.

Anaesthesiological strategies to improve outcome in liver transplantation recipients

Graft and patients survival are the main goal of anesthesiological management in patients undergoing liver transplantation (LT). Even if anesthesiological practice sustained major developments over time, some evidence-based intraoperative strategies have not yet been widely applied. The aim of this review was to summarize intraoperative anesthesiological strategies which could have the potential to improve LT graft and/or recipient survival. Monitoring must be as accurate as possible in order to manage intraoperative hemodynamic changes. The pulmonary artery catheter still represents the more reliable method to monitor cardiac output by using the intermittent bolus thermodilution technique. Minimally invasive hemodynamic monitoring devices may be considered only in stable cirrhotic patients. Goal-directed fluid-therapy has not yet defined for LT, but it could have a role in optimizing the long-term sequelae associated with volume depletion or overload. The use of vasopressor may affect LT recipient's outcome, by preventing prolonged hypotension, decreasing blood products transfusion and counteracting hepato-renal syndrome. The use of viscoelastic point of care is also warranted in order to reduce blood products requirements. Decreasing mechanical ventilation time, when it is feasible, may considerably improve survival. Finally, monitoring the depth of anesthesia when integrated into an early extubation protocol might have a positive effect on graft function.

Minimum alveolar concentration threshold of sevoflurane for postoperative dream recall

BACKGROUND

Many factors affect postoperative dream recall, including patient characteristics, type of anesthesia, timing of postoperative interview and stress hormone secretion. Aims of the study were to determine whether Bispectral Index (BIS)-guided anesthesia might decrease sevoflurane minimum alveolar concentration (MAC) when compared with hemodynamically-guided anesthesia, and to search for a MAC threshold useful for preventing arousal, dream recall and implicit memory.

METHODS

One hundred thirty patients undergoing elective thyroidectomy were enrolled. Anesthesia was induced with propofol 2 mg kg(-1), fentanyl 3 mcg kg(-1) and cis-atracurium 0.15 mg kg(-1). For anesthesia maintenance, patients were randomly assigned to one of two groups: a BIS-guided group in which sevoflurane MAC was adjusted on the basis of BIS values, and a hemodynamic parameters (HP)-guided group in which MAC was adjusted based on HP. An auditory recording was presented to patients during anesthesia maintenance. Dream recall and explicit/implicit memory were investigated upon awakening and approximately after 24 h.

RESULTS

Mean sevoflurane MAC during auditory presentation was similar in the two groups (0.85 ± 0.16 and 0.87 ± 0.17 [P = 0.53] in BIS-guided and HP-guided groups, respectively). Frequency of dream recall was similar in the two groups: 27% (N. = 17) in BIS-guided group, 18% (N. = 12) in HP-guided group, P = 0.37. In both groups, dream recall was less probable in patients anesthetized with MAC values ≥ 0.9 (area under ROC curve = 0.83, sensitivity = 90%, and specificity = 49%).

CONCLUSION

BIS-guided anesthesia was not able to generate different MAC values compared to HP-guided anesthesia. Independent of the guide used for anesthesia, a sevoflurane MAC over 0.9 was required to prevent postoperative dream recall.

Behavioural, psychological, and temperamental predictors of risk suicide trend after brief psychodynamic psychotherapy

BACKGROUND

Evidence has shown that psychotherapy is effective for depression, whereas the outcome for suicide risk is unclear.

AIM

It was to investigate whether possible pre-treatment predictors of suicide risk (SR) decrease after a brief psychodynamic psychotherapy treatment and at follow-up.

PATIENTS AND METHODS

Forty-one patients were assessed at: baseline (T0) for clinical history, clinical family history, physical diseases, type of suffered abuse; after the treatment (T1); and, at six-month follow-up (T2) for mood ratings, temperamental features, and SR levels.

RESULTS

The levels of depression and cyclothymia decreased at T1 and T2 compared to T0; however, the distribution of the patients with high SR level was similar between T0 and T1, and at T2 it increased. T1-T0 SR (Δ1SR) was correlated with suicidality in the last month and with depression levels at T0; T2-T0 SR (Δ2SR) was correlated with many historical, clinical, and temperamental variables; T2-T1 SR (Δ3SR) was correlated with the presence of previous psychotherapy, abuse, and anxiety. Linear regression models revealed that Δ1SR was predicted by the suicidality in the last month; Δ2SR was not significantly predicted by any variable; and, Δ3SR was predicted by anxiety.

CONCLUSIONS

The treatment was able to decrease the depression but not the SR. Findings confirm the difficulty of affecting SR and the importance of carefully considering the anxiety and the previous experiences of abuse in order to manage the interruption of the psychotherapy.

Uricemia and homocysteinemia: nontraditional risk factors in the early stages of chronic kidney disease--preliminary data

BACKGROUND

Patients with chronic kidney disease (CKD) show a risk of cardiovascular death, which is 10-100 times higher than that in the general population. This increase is not completely explained by the traditional cardiovascular risk factors. Hyperuricemia and hyperhomocysteinemia are highly prevalent in CKD. Patients suffering from these complications present accelerated atherosclerosis, determined mainly from the endothelial dysfunction that carries out a central role in the pathogenesis of cardiovascular diseases.

AIM

The hypothesis was that brachial artery flow mediated dilation (FMD) and carotid intima-media thickness (cIMT) evaluation can be considered as early and systemic markers of atherosclerosis and that nontraditional risk factors, such as hyperhomocysteinemia and hyperuricemia, are associated with early endothelial dysfunction and vascular damage in patients suffering from first- and second-stage CKD.

PATIENTS AND METHODS

The study comprised 50 patients, 10 for each CKD stage, and 15 age- and sex-matched healthy controls. We compared the traditional and nontraditional factors for cardiovascular diseases with alterations of vascular reactivity, such as cIMT, and brachial artery FMD, in patients affected by CKD with those in the control group.

RESULTS

In our study, hyperuricemia was significantly and independently associated with brachial artery FMD reduction (p = 0.007), while hyperhomocysteinemia was significantly and independently associated with carotid intima-media thickening (p = 0.021) in patients at Stage I and II KDOQI (Kidney Disease Outcomes Quality Initiative).

CONCLUSIONS

In our study, we found a progressive increase in the inflammatory indices and endothelial dysfunction at the early stages of CKD. Hyperuricemia and hyperhomocysteinemia were associated with IMT and FMD at Stage I-III KDOQI, and can be used as markers of subclinical atherosclerosis, especially in nephropathic patients with high cardiovascular risk.

Stress-related biomarkers of dream recall and implicit memory under anaesthesia

The aim of this study was to investigate whether auditory presentation of a story during general anaesthesia might influence stress hormone changes and thus affecting dream recall and/or implicit memory. One hundred and ten patients were randomly assigned either to hear a recording of a story through headphones or to have routine care with no auditory recording while undergoing laparoscopic cholecystectomy. Anaesthesia was standardised. Blood samples for cortisol and prolactin assays were collected 20 min before anaesthesia and 5 min after pneumoperitoneum. Dream recall and explicit/implicit memory were investigated upon awakening from anaesthesia and approximately 24 h after the end of the operation. Auditory presentation was associated with lower intra-operative serum prolactin concentration compared with control (p = 0.0006). Twenty-seven patients with recall of dreaming showed higher intra-operative prolactin (p = 0.004) and lower cortisol (p = 0.03) concentrations compared with those without dream recall. The knowledge of this interaction might be useful in the quest to ensure postoperative amnesia.

Update on post-traumatic stress syndrome after anesthesia

BACKGROUND

Between 0.5% and 2% of surgical patients undergoing general anesthesia may experience awareness with explicit recall. These patients are at a risk for developing anxiety symptoms which may be transient or can lead to post-traumatic stress disorder (PTSD).

AIM

The aim of this review was to assess the prevalence of PTSD after intraoperative awareness episodes and analyze patients' complaints, type and timing of assessment used.

METHODS

PubMed, MEDLINE and The Cochrane Library were searched up until October 2012. Prospective and retrospective studies on human adult subjects describing prevalence of PTSD and/or psychological sequalae after awareness episodes were included.

RESULTS

Seven studies were identified. Prevalence of PTSD ranged from 0 to 71%. Acute emotions such as fear, panic, inability to communicate and feeling of helplessness were the only patients' complaints that were significantly correlated to psychological sequelae including PTDS. There were cases that reported psychological symptoms after 2-6 hours from awakening (%) or 30 days after (%). Previous studies used psychological scales lacking of dissociation assessment.

CONCLUSIONS

Whenever an awareness episode is suspected, a psychological assessment with at least three interviews at 2-6 h, 2-36 h and 30 days must be performed in order to collect symptoms associated with both early and delayed retrieval of traumatic event. As a dissociative state could hide the expression of reactive symptoms after intraoperative awareness, future studies should be focused on detecting dissociative symptoms in order to carry out a prompt and appropriate treatment aimed at avoiding long-term psychological disability.

Low values of left ventricular ejection time in the post-anhepatic phase may be associated with occurrence of primary graft dysfunction after orthotopic liver transplantation: results of a single-centre case-control study

BACKGROUND

Previous investigations on risk factors for orthotopic liver transplantation (OLT) surgery have not analyzed hemodynamic aberrations in great detail. Moreover, the usefulness of esophageal Doppler monitoring has not been extensively studied in this clinical setting. The aim of this study was to evaluate if the occurrence of primary graft dysfunction (PGD) may be anticipated by hemodynamic indexes measured by esophageal Doppler (ED) monitoring system as well as by pulmonary artery catheter (PAC) in patients undergoing OLT.

MATERIALS AND METHODS

38 OLT recipients were studied. Patients with acute liver failure or having non treated esophageal varices and those transplanted with marginal donors were excluded from the study. The haemodynamic data - measured by ED monitoring system (HemosonicTM 100, Arrow, OK, USA) and PAC - collected at the following 3 time points were considered for statistical analysis: 30 minutes after the induction of anesthesia but before skin incision, T0; 20 minutes after liver dissection, T1; at the beginning of biliary reconstruction, T2. On the basis of early outcome (72 hours after OLT), patients were distinguished into two groups: those with PGD (grade III-IV of Toronto classification) and those without PGD (grade I-II).

RESULTS

LVETc (left ventricular ejection time) values, registered at the beginning of biliary reconstruction (T2), were lower in patients with PGD compared to those without PGD (p < 0.000), while there were no differences in hemodynamic parameters derived from PAC between the two groups.

CONCLUSIONS

Since LVETc is related to preload, the results of this study would suggest that normovolemia could be the end point of a fluid replacement strategy in OLT setting.

Effect of anesthesia in a patient with pre-existing anisocoria

In this case report, we describe an accentuation of a pre-existing anisocoria shortly after tracheal intubation in a patient undergoing thyroidectomy. A 45-yr-old female patient with unequal pupillary diameter (right 2 mm > than left) and decreased light reflex in the right eye--due to a previous eye trauma--was scheduled for thyroidectomy because of multinodular goiter. Anesthesia was induced with propofol 2,5 mg/kg, fentanyl 3 mcg/kg and cisatracurium 0.15 mcg/kg. Immediately after tracheal intubation, examination of the right eye revealed a markedly dilated pupil (8 mm) which was nonreactive to direct and consensual light reflex. The left pupil was 2 mm, and normally reactive to light. An increase in heart rate was also registered (> 20% of baseline) with spontaneous return to baseline within 2 minutes. The right pupil returned to preoperative size within approximately one hour after awakening. From this case report, it emerges that a preexisting anisocoria may be exacerbated during anesthesia probably due to incomplete abolition of response to painful stimulus, such as tracheal intubation, provided by anesthetic drugs in the affected eye. The main contributing factor for accentuation of anisocoria could be sympathetic dominance in the pupil with pre-existing mechanical interruption in compensatory parasympathetic mechanisms.

Analgesia in thoracic surgery: review

Post-thoracotomy pain is one of the most severe types of postoperative pain. It can last up to 2 months and can become chronic in 30% of patients. Pain relief after thoracic surgery is of particular significance, not only for ethical considerations but also for reduction of postoperative pulmonary and cardiac complications. Because of the difficulty in pain control, many approaches have been suggested, but a multimodal therapeutic strategy that provides a central or peripheral block associated with nonsteroidal anti-inflammatory (NSAID) and adjuvant drugs is now the cornerstone of treatment, offering the possibility of reducing opioid requirements and side effects. Thoracic epidural analgesia with local anesthetics and opioids is regarded as the gold standard treatment for post-thoracotomy pain management because it results in early extubation, better ventilatory mechanisms and gas exchange, decreased incidence of atelectasis, pneumonia and chronic postoperative pain. When epidural analgesia is contraindicated or cannot be performed, other regional techniques of analgesia can be used. An alternative method of providing adequate pain relief is a thoracic paravertebral block: continuous paravertebral infusion of local anesthetic via a catheter placed percutaneously or under direct vision during thoracotomy. This is effective in controlling postoperative pain and in preserving pulmonary function. Other techniques, such as intercostal and interpleural blocks, are rarely utilized, whereas a single shot of intrathecal injection of a hydrophilic opioid, such as morphine, appears to be effective. Cryoanalgesia, which is successful in the immediate postoperative period, has been abandoned for its brief duration and increased incidence of chronic pain.

Epidural infusion of levobupivacaine and sufentanil following thoracotomy

A prospective, randomised, double-blind study was conducted to compare the efficacy of two doses of levobupivacaine combined with sufentanil for continuous epidural infusion following thoractomy. A total of 72 patients undergoing lobectomy or pneumonectomy were enrolled. An epidural catheter was inserted between the levels of T4 and T6 before induction of anaesthesia and a loading dose of levobupivacaine and sufentanil was administered. At the end of surgery an epidural infusion was commenced at 5 mlxh(-1) and continued for 48 h. Patients were randomly allocated to receive either levobupivacaine 0.125% (group A) or 0.0625% (group B) and all patients also received sufentanil (1 microgxml(-1)). Visual analogue pain scores after coughing (VASi) were always higher in group B (p < 0.05); VAS pain scores at rest were higher for the first 4 h and at 16 and 28 h in group B (p < 0.05). Total morphine consumption and requests number was lower in group A (p < 0.05). Better pain relief was achieved using epidural 0.125% levobupivacaine.

Changes in hemodynamics during isoflurane and propofol anesthesia: a comparison study

OBJECTIVES

Volatile anesthetics are thought to impair cerebral autoregulation more than i.v. anesthetics. However, few comparative studies have been carried out in humans. The aim of our study was to evaluate the differences in cerebral hemodynamic changes after introduction of isoflurane (a volatile anesthetic) and propofol (an i.v. anesthetic).

METHODS

Eighteen consecutive patients submitted to laparoscopic cholecystectomy were selected. After the induction, anesthesia was maintained by isoflurane (one minimum alveolar anesthetic concentration) during the first part of the surgical operation, and then by propofol (5 mg/kg/hour i.v.). Ventilation was adjusted to maintain a constant end-tidal CO(2). Middle artery flow velocity was assessed by means of transcranial Doppler ultrasonography. Arterial blood pressure, heart rate (HR), capnometry, pulse oxymetry, inspired fraction of O(2), and body temperature, were monitored.

RESULTS

Cerebral artery velocity, HR, and mean arterial pressure all significantly increased from baseline after the introduction of isoflurane (p<0.05); the HR and mean arterial blood pressure showed no significant difference between the isoflurane and propofol phases. Isoflurane anesthesia induced a significant increase in cerebral blood velocity. Propofol introduction led to a significant decrease in cerebral artery velocity (p<0.05).

CONCLUSIONS

Propofol but not isoflurane decreased cerebral blood velocity thus restoring cerebral autoregulation and the coupling between cerebral blood flow and cerebral metabolism.

Use of levobupivacaine for the treatment of postoperative pain after thoracotomies

Continuous thoracic epidural analgesia with an opiod-local anaesthetic mixture is the most appropriate strategy to control postoperative pain in thoracic surgery. Levobupivacaine, the pure S(-) enantiomer of racemic bupivacaine, has less cardiotoxic and neurotoxic potential but similar anaesthetic properties of its native agent. There are no studies in thoracic surgery that had established the minimal efficient concentration of this anaesthetic when used with an epidural opioid. The advantages of administering opioids in addition to local anaesthetics in the epidural space are the possibility to decrease dose and consequently side-effects of each drug and to exploit the documented synergy between these different categories of drugs in producing segmental epidural analgesia. In our departmental study (unpublished data), 2 different concentration of levobupivacaine (Group A: 0.125% and Group B: 0.0625%) combined with sufentanil (1 mg/mL) were administered in continuous epidural post-thoracotomy infusion to investigate quality of analgesia, motor block and side-effects. An intravenous PCA system has been used in the postoperative period to evaluate rescue morphine consumption. Preliminary results showed that patients of each group reported similar VAS at rest although a better pain control during cough resulted in group A. Patients receiving levobupivacaine at 0.125% presented low incidence of nausea, vomiting and pruritus probably because of the smaller amount of rescue morphine administered. At the concentration of 0.125% epidural levobupivacaine in combination with sufentanil allowed to obtain a good pain control with no adverse effects and motor block at all.

Auditory evoked potentials

Auditory evoked potentials (AEPs) are an electrical manifestation of the brain response to an auditory stimulus. Mid-latency auditory evoked potentials (MLAEPs) and the coherent frequency of the AEP are the most promising for monitoring depth of anaesthesia. MLAEPs show graded changes with increasing anaesthetic concentration over the clinical concentration range. The latencies of Pa and Nb lengthen and their amplitudes reduce. These changes in features of waveform are similar with both inhaled and intravenous anaesthetics. Changes in latency of Pa and Nb waves are highly correlated to a transition from awake to loss of consciousness. MLAEPs recording may also provide information about cerebral processing of the auditory input, probably because it reflects activity in the temporal lobe/primary cortex, sites involved in sounds elaboration and in a complex mechanism of implicit (non declarative) memory processing. The coherent frequency has found to be disrupted by the anaesthetics as well as to be implicated in attentional mechanism. These results support the concept that the AEPs reflects the balance between the arousal effects of surgical stimulation and the depressant effects of anaesthetics. However, AEPs aren't a perfect measure of anaesthesia depth. They can't predict patients movements during surgery and the signal may be affected by muscle artefacts, diathermy and other electrical operating theatre interferences. In conclusion, once reliability of the AEPs recording became proved and the signal acquisition improved it is likely to became a routine feature of clinical anaesthetic practice.

[Anesthesia and concomitant pathologies: anesthesia in the elderly patient]

With the increase in the average age of the population, more and more older persons undergo surgery. Major surgery, cardiovascular, orthopaedic and abdominal interventions expose the elderly patient to a significant risk for postoperative morbidity and mortality. This is not only related to the advanced age of these subjects, which is a recognized independent risk factor, but also to the aging process itself and to the greater prevalence of heart and lung diseases affecting this population segment. An important role is also played by the so-called physiologic modification found in subjects without recognized illnesses. Reduced organ function reserve requires accurate preoperative assessment that takes into account cardiovascular reserve and physiologic and pathologic alterations in the respiratory system that may predispose the patient to hypoxemia and favour the development of postoperative infection. Moreover, alterations in pharmacokinetics and pharmacodynamics require individualized drug dosing. Particular attention should also be directed at the prevention of postoperative cognitive disorders that favour the development of complications and negatively affect postoperative recovery of body function.

Relationship between awareness and middle latency auditory evoked responses during surgical anaesthesia

BACKGROUND

Some studies support the view that meaningful auditory input can be processed by the brain during apparent surgical anaesthesia. Consequently, patients may be able to remember some information implicitly after anaesthesia as well through a 'dream-like process' (subconscious awareness). The aim of this study was to investigate the presence of subconscious awareness during anaesthesia and to examine its relationship to the mid-latency auditory evoked responses (MLAERs).

METHODS

We studied 40 patients, ASA I-II, undergoing laparoscopic cholecystectomy. General anaesthesia was induced with thiopental 5 mg kg(-1), fentanyl 3 micro g kg(-1), and vecuronium 0.08 mg kg(-1). For the maintenance of anaesthesia, patients were randomly assigned to one of four anaesthetic regimen groups: sevoflurane+air in oxygen 40%; sevoflurane+nitrous oxide 60%; isoflurane+air in oxygen 40%; and isoflurane+nitrous oxide 60%. MLAERs were recorded before anaesthesia, at 1 MAC of inhaled anaesthetic and then 30 min after awakening. An audiotape with one of four stories was played immediately after intraoperative MLAER recording. Explicit and implicit memory was assessed 24 h after awakening.

RESULTS

None of the patients had explicit recall. One of the patients from the isoflurane-air group showed implicit memory of listening to the audiotape. A dream-like process, in which they remembered implicitly the story played during anaesthesia, occurred in one of the patients from the sevoflurane-nitrous oxide group. In the patients with subconscious awareness, MLAERs were similar to that of the awake state with a Pa latency increase of less than 8.87. When there was a marked increase in Pa latency during anaesthesia, no subconscious awareness was observed. No statistically significant differences were found between Pa latency before and after anaesthesia.

CONCLUSIONS

MLAERs may help to predict subconscious cerebral processing of auditory inputs during anaesthesia.

Preliminary study on the feeding habits of roe deer (Capreolus capreolus) in the western Alps

Roe deer feeding habits were studied in the western Alps during the summer season using the faecal analysis method. The diet of cattle grazing in the same area was also investigated and the trophical niche overlap between the two species was determined. The roe deer diet was found very variable and mostly composed of dicotyledons, with Leguminosae and Cistaceae as prevalent species. Monocotyledons, mainly represented by Graminaceae, were consumed to a lesser extent. A significant preference was observed for Cistaceae and other dicotyledons whereas a significant refuse was observed for Graminaceae and Asteraceae. These data confirmed the roe deer's behaviour to select food with a better nutritive value. Despite the differences between the cattle and roe deer's diets, the trophical niche overlap was quite high. This can be explained by the homogeneity of the plants covering the whole area which probably limited food selection by the roe deer.