Predictive power of modified frailty index score for pulmonary complications after major abdominal surgery in the elderly: a single centre prospective cohort study.

OBJECTIVE: The primary aim of this prospective cohort study was to evaluate the usefulness of the modified Frailty Index (mFI) score to predict postoperative pulmonary complications (PPCs) in elderly patients undergoing major open abdominal surgery. The secondary purpose was to compare the prediction power of mFI, Ariscat (Assess Respiratory Risk in Surgical Patients in Catalonia), and American Society physical status classification (ASA) scores. PATIENTS AND METHODS: After local Ethical Committee approval, 105 patients aged ≥65 years undergoing open major abdominal surgery were enrolled. Clinical data were compared between patients with or without PPCs (including respiratory failure, aspiration pneumonia, pulmonary infection, pleural effusion, pneumothorax, atelectasis, bronchospasm or un-planned re-intubation). t-test or χ2-test were performed for univariate analyses. Logistic regression analysis was used to identify independent predictors of PPCs. Non parametric ROC (Receiver Operating Characteristic) was used for cut-off calculation. AUCs (areas under ROC curve) of preoperative scores were compared using χ2-test. RESULTS: PPCs prevalence (11.3%) was associated with increased mFI, ASA, and Ariscat scores, greater age, hemoglobin levels <10 g/dl, peripheral oxygen saturation <95% (p=0.0001) and longer surgery duration. Logistic regression showed that mFI (p=0.0001) and Ariscat (p=0.04) were independent predictors of PPCs. The predictive power of mFI (AUC=0.90) was similar to that of Ariscat (AUC=0.81) (χ2=2.53; p=0.11) but greater than that of ASA (AUC=0.69) (χ2=9.85; p=0.002). An mFI≥0.18 was predictive of PPCs (sensitivity=90.91%; specificity=79.07%). An Ariscat score of 27 was the cut-off identified as determining factor for PPCs occurrence (sensitivity=90.91%; specificity=51.16%). CONCLUSIONS: Elderly patients with an mFI ≥0.18 and/or an Ariscat score ≥27 were at higher risk of PPCs after open major abdominal surgery. More attention should be paid to these patients by implementing both strict monitoring and strategies for PPCs prevention in the perioperative period.

Lung volumes, respiratory mechanics and dynamic strain during general anaesthesia.

BACKGROUND: Driving pressure (ΔP) represents tidal volume normalised to respiratory system compliance (CRS) and is a novel parameter to target ventilator settings. We conducted a study to determine whether CRS and ΔP reflect aerated lung volume and dynamic strain during general anaesthesia. METHODS: Twenty non-obese patients undergoing open abdominal surgery received three PEEP levels (2, 7, or 12 cm H2O) in random order with constant tidal volume ventilation. Respiratory mechanics, lung volumes, and alveolar recruitment were measured to assess end-expiratory aerated volume, which was compared with the patient's individual predicted functional residual capacity in supine position (FRCp). RESULTS: CRS was linearly related to aerated volume and ΔP to dynamic strain at PEEP of 2 cm H2O (intraoperative FRC) (r=0.72 and r=0.73, both P<0.001). These relationships were maintained with higher PEEP only when aerated volume did not overcome FRCp (r=0.73, P<0.001; r=0.54, P=0.004), with 100 ml lung volume increases accompanied by 1.8 ml cm H2O-1 (95% confidence interval [1.1-2.5]) increases in CRS. When aerated volume was greater or equal to FRCp (35% of patients at PEEP 2 cm H2O, 55% at PEEP 7 cm H2O, and 75% at PEEP 12 cm H2O), CRS and ΔP were independent from aerated volume and dynamic strain, with CRS weakly but significantly inversely related to alveolar dead space fraction (r=-0.47, P=0.001). PEEP-induced alveolar recruitment yielded higher CRS and reduced ΔP only at aerated volumes below FRCp (P=0.015 and 0.008, respectively). CONCLUSIONS: During general anaesthesia, respiratory system compliance and driving pressure reflect aerated lung volume and dynamic strain, respectively, only if aerated volume does not exceed functional residual capacity in supine position, which is a frequent event when PEEP is used in this setting.

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.

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.

Suspect carbon dioxide embolism during retroperitoneoscopic adrenalectomy.

During a retroperitoneoscopic adrenalectomy in the prone position, a sudden increase in end-Tidal CO2 (EtCO2) (from 42 to 68 mmHg) followed by an abrupt decrease (from 68 to 35 mmHg) was observed, concomitantly with a right adrenal vein laceration. Heart rate decreased to 30 bpm, and the systolic blood pressure decreased to 40 mmHg. The patient was slightly turned in the left lateral and Trendelenburg position and vasoactive drugs were administered. The systemic blood pressure, EtCO2, CO2 elimination (VCO2) and pulse oximetry (SpO2) progressively improved within 10 minutes and, at the end of the surgery, the blood pressure recovered from hypotension. ECG returned to normal, with sinusal rhythm and heart rate approximately 70 bpm. The patient was extubated and moved to the Intensive Care Unit (ICU). This case suggests that gas embolisms may occur during retroperitoneoscopic adrenalectomy, and acute changes in EtCO2 should alert the clinicians to these rare but potentially lethal complication. EtCO2 monitoring is essential during laparoscopy, as it may help an early detection of CO2 embolism, characterized by a transient and rapid increase in EtCO2, followed by an abrupt decrease.

Use of an esophageal echo-Doppler device during liver transplantation: preliminary report.

Determination of cardiac output (CO) is crucial for perioperative monitoring of orthotopic liver transplant (OLT) recipients. A pulmonary artery catheter (PAC) has always been considered the "gold standard" of hemodynamic monitoring. The aim of this study was to evaluate the suitability of a transesophageal echo-Doppler device (ED) as a minimally invasive device to measure CO in OLT. ED was compared with the standard PAC technique taking into account the disease severity of OLT recipients as defined by the model for end-stage liver disease (MELD) score. We enrolled 42 cirrhotic patients scheduled for OLT 3 thermodilution CO measurements were taken by a PAC and the most recent ED measurement (CO(ED)) was also recorded. Paired measurements of CO were performed at standard times, unless there were additional clinical needs. Recipients were stratified into 3 groups according to MELD score: MELD score < or = 15 (14 patients); MELD score between 16 and 28 (17 patients); and MELD score > or = 29 (11 patients). We performed 495 paired measurements of CO. Mean bias was 0.34 +/- 0.9 L/min and limits of agreement were -1.46 and 2.14 L/min. In patients with MELD score <15, the bias was 0.12 +/- 0.55. The ED results were not interchangeable with PAC, because of the large limits of agreement. However, in cirrhotic patients with MELD scores <15, the precision of the new method was similar to that of PAC; therefore, in this subset of patients, it may represent a reliable alternative to PAC.

Molecular adsorbent recirculating system (Mars) in patients with primary nonfunction and other causes of graft dysfunction after liver transplantation in the era of extended criteria donor organs.

Liver dysfunction is an important cause of morbidity and mortality after orthotopic liver transplantation (OLT). The Molecular Adsorbent Recirculating System (MARS) is an albumin-based dialysis system designed to enhance the excretory function of a failing liver. MARS has been successfully used in patients affected by advanced liver disease and presenting with severe cholestasis. The aim of this study was to evaluate the safety and clinical efficacy of MARS in patients with liver dysfunction after OLT. Seven patients (primary nonfunction, 2 patients; graft dysfunction, 5 patients) fulfilled the inclusion criteria of serum bilirubin level >15 mg/dL and least 1 of the following clinical signs: hepatic encephalopathy (HE) > or = grade II, hepatorenal syndrome (HRS), and intractable pruritus. Graft and patient survival rates at 6 months were 42.8% and 57.1%, respectively. All patients tolerated MARS treatment, with no adverse event. In all patients, a decrease in serum bilirubin (P < .05), bile acids (P < .05), serum creatinine, and ammonia levels was observed after treatment with MARS. A considerable improvement of HE, as well as renal and synthetic liver functions, was observed in 4 of 5 patients with graft dysfunction, but not among those with primary nonfunction. The patients with intractable pruritus showed significant improvement of this symptom after MARS therapy. Thus, MARS is a safe, therapeutic option for the treatment of liver dysfunction after OLT. Further studies are necessary to confirm whether this treatment is able to improve both graft and patient survival.

Balanced anestesia versus total intravenous anestesia for kidney transplantation.

AIM: An ideal anesthetic regimen for kidney transplantation should be able to assure haemodynamic stability to obtain an optimal graft reperfusion. The aim of this study was to compare 2 regimens of anesthesia for patients submitted to kidney transplantation. METHODS: We studied 40 patients: 20 subjects (Group A) received balanced anesthesia with thiopental, fentanyl and isoflurane, to the others 20 (Group B), a total intravenous anesthesia (TIVA) with propofol and remifentanyl was given. In both groups muscle relaxation was obtained with a bolus of cisatracurium followed by a continuous infusion. We performed standard clinical, invasive blood pressure and central venous pressure monitoring. Hemodyna-mic data have been collected at standard times. During the postoperative period we evaluated the recovery (Aldrete Score) in the recovery room and the analgesia (VAS) at 1, 6, 24 h after the end of surgery. RESULTS: The trend of hemodynamic parameters did not show statistically significant differences between the 2 groups. We observed statistically significant differences concerning the quality of the recovery and the postoperative analgesia. The recovery in group B was faster than in group A, but in group A the pain control was better than in group B at least during the first postoperative hour. CONCLUSIONS: For their pharmacokinetic properties, propofol, remifentanyl and cisatracurium allow to obtain a good control of the hemodynamic parameters and a fast and safe recovery of consciousness. Total intravenous anesthesia regimen seems to be an alternative to the balanced anesthesia for patients undergoing kidney transplantation.

Comparison of positive end-expiratory pressure with reverse Trendelenburg position in morbidly obese patients undergoing bariatric surgery: effects on hemodynamics and pulmonary gas exchange.

BACKGROUND: Anesthetized morbidly obese patients often exhibit impaired pulmonary gas exchanges, mostly because of a reduction in functional residual capacity. At present, several approaches are suggested to ventilate these patients. METHODS: The efficiency of positive end-expiratory pressure (PEEP) and reverse Trendelenburg position (RTP) were compared in order to improve oxygenation in 20 morbidly obese patients undergoing bariatric surgery. RESULTS: Both PEEP and RTP determined a significant decrease in alveolar-arterial oxygen difference and an increase in total respiratory compliance (Ctot). RTP resulted in lower airway pressures than PEEP with similar improvements in Ctot and oxygenation. Concerning hemodynamic parameters, cardiac output (CO) significantly decreased with both PEEP and RTP. CONCLUSIONS: RTP and PEEP can be considered adequate ventilatory settings for morbidly obese patients, without any significant difference with regard to gas exchange improvement. However, the decrease in CO may partially counteract the beneficial effects on oxygenation of these ventilatory settings.

Effects of remifentanil infusion bis-titrated on early recovery for obese outpatients undergoing laparoscopic cholecystectomy.

BACKGROUND: In obese patients functional residual capacity comes down with a possible hypoxemia in postoperative period. In fact many studies has been begun to determine optimum ventilation regulation and the best position for these patients, but the question has not been solved. As remifentanil can reduce of 50% the inhalatory anaesthetic request and reverse Trendelemburg position is extremely useful for these patients, we hypothesized that use of a continuous remifentanil infusion during balanced anaesthesia with sevoflurane, BIS-titrated, associated to reverse Trendelem-burg position could facilitate emergence from anaesthesia in obese patients undergoing laparascopic cholecystectomy. METHODS: We studied 40 patients, ASA II class, with higher than 30 kg/m2 body mass index, undergoing to laparoscopic cholecystectomy. All the patients, in operating room, received standard monitoring and BIS sensor application. All the data were continuously collected. Induction of anaesthesia has been with a refracted bolus in 120 sec of remifentanil 1 mg/kg, followed by propofol 1.5 mg/kg and cisatracurium 0.15 mg/kg. Maintenance of anaesthesia has been by balanced anaesthesia with continuous remifentanil infusion, ventilating patients with sevoflurane in oxygen and air. Patients were randomized into two homogenous groups. Into the control group has been varied sevoflurane inspiratory concentration on the ground of BIS value (from 0.3% to 3%), while into remifentanil group remifentanil infusion has been varied (from 0.25 to 2 mg/kg/min) to maintain medium pressure values which don't stray more than 25% from basal values, on the ground of BIS values. On pre-established times of operation, respiratory mechanics and blood gases were examined. RESULTS: As it was to expect, sevoflurane concentration variations resulted very high in control group compared to remifentanil group. Awakening time, extubation, orientation and transfer to PACU (postanaesthesia care unit) resulted significantly lower than remifentanil group. CONCLUSIONS: Concluding, remifentanil infusion, BIS-titrated, facilitates awakening times from balanced anaesthesia with Sevoflurane in obese patients, submitted to laparoscopic cholecystectomy.

Volatile anesthesia in bariatric surgery.

BACKGROUND: Obesity causes anesthesiologists a broad variety of perioperative theoretical and practical problems. The aim of this study was to compare two protocols of anesthesia employing Isoflurane and Sevoflurane and evaluate the cardiorespiratory parameters, postoperative recovery and analgesia. METHODS: 90 patients underwent biliopancreatic diversion. 60 patients (group A) received Isoflurane and 30 patients (group B) were anesthetized with Sevoflurane. Intraoperative monitoring consisted of EKG, invasive arterial pressure, SpO2, EtCO2, Etanest, Spirometry, urinary output and TOF. Cardiorespiratory parameters and end tidal expiratory concentrations of volatile agents were collected during specific phases of surgery: 1) before induction of anesthesia, 2) after intubation, 3) after skin incision, 4) after positioning of costal retractors, 5) in the reverse Trendelenburg position, 6) end of surgery. During the postoperative period the Aldrete test was carried out to evaluate the recovery from anesthesia. VAS was administered for 6 hours after the end of surgery to set the quality of analgesia. RESULTS: No statistically significant differences in cardiorespiratory parameters were found between the two groups. Extubation time was significantly less in the Sevoflurane Group than in the Isoflurane (15 +/- 7 min vs 24 +/- 5 min, p < 0.05). The Sevoflurane Group showed an Aldrete score significantly higher than the Isoflurane (8.8 +/- 0.3 vs 8.1 +/- 0.4, p < 0.05). VAS values did not show statistical differences. CONCLUSION: The introduction of Sevoflurane, a volatile agent with rapid pharmacokinetic properties, seems to offer an interesting application in these patients.

Bispectral index monitoring in sevoflurane and remifentanil anesthesia. Analysis of drugs management and immediate recovery.

BACKGROUND: Recent studies have suggested that electroencephalogram bispectral index (BIS) monitoring can improve recovery after anaesthesia and save money by shortening patients postoperative stay. The aim of the study is to evaluate the management of drugs and to measure immediate recovery after anaesthesia with or without BIS monitoring. METHODS: We studied 90 patients undergoing abdominal surgery randomly allocated to one of two groups of 45 each with or without BIS monitoring. Standard monitoring (EKG, arterial oxygen saturation and non-invasive blood pressure) was applied. All groups were monitored with BIS, using electrodes (Zipprep, Aspect Medical Systems) applied to the forehead. In the group 2 the BIS value was blinded to the anaesthesiologist. The BIS value was displayed using Spacelabs Medical BIS Ultraview Monitor. After obtaining baseline values for the BIS index (group 1) and haemodynamic data (all groups) anaesthesia was induced with a bolus dose of remifentanil and TPS, and vecuronium. The anaesthesia was maintained with Remifentanil and Sevoflurane. At standard times BIS, haemodynamic and respiratory parameters were recorded. Recovery times were measured by a study coordinator. Drug consumption was calculated. RESULTS: In group 1 the consumption of Sevoflurane decreased by 40 % while the consumption of remifentanil decreased by 10 % as compared to group 2. The use of vecuronium did not change in the 2 groups. In group 1 the time elapsed from cessation of anaesthetics to orientation decreased significantly. The difference was 5 min, from 11 to 6 min. CONCLUSIONS: BIS monitoring decrease both sevoflurane and remifentanil consumption, when compared to anaesthesia without BIS, with an immediate recovery after sevoflurane and remifentanil anaesthesia.

Arterial PCO2 and cardiovascular function during endoscopic neck surgery with carbon dioxide insufflation.

BACKGROUND: Endoscopic parathyroidectomy and thyroidectomy were introduced into clinical practice in 1995. Concerns about the use of carbon dioxide insufflation in the neck exist owing to reports of potential adverse metabolic and hemodynamic changes. HYPOTHESIS: Carbon dioxide insufflation in the neck may cause adverse effects on hemodynamic and blood gas levels. These adverse effects may reflect the level of pressure and duration of insufflation. METHODS: Fifteen pigs, 5 per group, underwent endoscopic thyroidectomy at 10, 15, and 20 mm Hg. Partial pressure of carbon dioxide (arterial), pH, cardiac output, central venous pressure, heart rate, and mean arterial pressure (MAP) were measured at baseline, 1 and 2 hours after carbon dioxide insufflation, and 30 minutes after desufflation. RESULTS: At 10 mm Hg, PaCO2 increased slightly but not significantly, and neither acidosis nor adverse hemodynamic changes were observed. Hypercarbia, moderate acidosis, and a slight increase in MAP occurred in pigs undergoing surgery at 15 mm Hg (MAP increased to 88 +/- 2.4 mm Hg from a baseline value of 78 +/- 3.53 mm Hg; P<.05). Pigs undergoing surgery at 20 mm Hg experienced severe hypercarbia and acidosis, as well as a significant decrease in MAP (P<.05). Central venous pressure decreased at 1 hour (P<.05) and increased at 2 hours (P<.05) in pigs undergoing surgery at 15 and 20 mm Hg. After desufflation, PaCO2 and pH levels were normal for the 10 and 15 mm Hg groups, while pigs undergoing surgery at 20 mm Hg developed a higher degree of hypercarbia and acidosis (P =.001). CONCLUSIONS: Carbon dioxide neck insufflation is safe at 10 mm Hg. The use of insufflation pressures higher than 15 mm Hg should be avoided due to the potential risk for metabolic and hemodynamic complications.