Changes in thenar muscle tissue oxygen saturation assessed by near-infrared spectroscopy during weaning from mechanical ventilation.

BACKGROUND: Tissue oxygen saturation (StO2) measured by near-infrared spectroscopy (NIRS) has been used to provide information on local tissue oxygenation in different clinical settings. This study aims to determine the effect of weaning from mechanical ventilation on thenar muscle StO2. METHODS: In consecutive critically ill mechanically ventilated patients, StO2 at the thenar eminence, along with a vascular occlusion test (VOT), were measured by NIRS, on mechanical ventilation and during a 2-hour T-piece spontaneous breathing trial (SBT). Hemodynamic, gas exchange and respiratory variables were recorded. RESULTS: Forty-four patients were included in this study, 25 tolerated the SBT and 19 failed. On mechanical ventilation, no differences in any measured variable were observed between patients who succeeded or failed. Two minutes after SBT start, StO2 was decreased in patients who failed whereas it did not change in patients who succeeded (P<0.001). For all data, 2 minutes after the start of SBT, StO2 significantly correlated with SaO2 (r=0.32, P=0.037) and with the respiratory frequency/tidal volume (f/VT) index (r=-0.34, P=0.023). VOT-derived StO2 downslope and StO2 upslope did not change significantly along the SBT test. The maximum StO2 value, its ratio to minimum StO2, and the post-VOT StO2 value decreased significantly in patients who failed whereas no change was found in those who succeeded the SBT (P=0.003, P=0.025 and P<0.001 respectively). StO2 and f/VT at the second minute of SBT yielded a receiver operator characteristics curve area value of 0.77 and 0.80, P=0.002, respectively, in detecting the SBT outcome. CONCLUSION: SBT failure was associated with a significant impairment of thenar muscle StO2. A decrease of StO2 at 2 minutes after disconnection from the ventilator was associated with SBT failure. Further validation is warranted.

The impact of spinal anaesthesia for caesarean delivery on coagulation assessed by thromboelastography.

BACKGROUND: Pregnancy and puerperium are associated with a hypercoagulable state. The aim of the study was to assess the impact of spinal anaesthesia on coagulation using thromboelastography in healthy term pregnant women undergoing elective caesarean delivery. METHODS: Thromboelastography was performed on 60 women undergoing elective caesarean delivery under spinal anaesthesia. As spinal anaesthesia has different effects on upper and lower extremity vasculature, venous blood samples were collected from both hand and foot, before and one hour after spinal injection. RESULTS: In the hand samples, R and K values decreased significantly from before to one hour after spinal injection (5.7±1.9 min versus 3.6±1.3 min, P<0.001 and 2.1±0.9 min versus 1.5±0.4 min, P<0.001, respectively). At the same times, significant increases in the alpha angle (58.6±9.1 degrees versus 65.6±7.5 degrees, P<0.001), MA (85.1±4.6 mm versus 87.0±3.8 mm, P<0.001) and CI (2.6±2.1 versus 4.9±1.5, P<0.001) were seen. No significant changes were found in thromboelastography parameters in samples collected from foot veins before and one hour after spinal injection, with the exception of the alpha angle (62.1±11.5 versus 66.5±8.8 degrees, P<0.012). CONCLUSION: In women undergoing caesarean delivery under spinal anaesthesia, enhanced coagulation thromboelastography parameters were observed in blood collected from hand veins. No changes were detected in the majority of parameters collected from the foot. Spinal anaesthesia has different effects on coagulation parameters in the hand and foot in pregnant women undergoing caesarean delivery.

Transcranial Doppler monitoring of middle cerebral flow velocity in a patient with a ventriculoperitoneal shunt undergoing laparoscopy.

Laparoscopic surgery is possibly associated with a risk of intracranial pressure (ICP) increase due to pneumoperitoneum in patients with ventriculoperitoneal shunts (VPS). Invasive techniques for shunt pressure monitoring are not routinely used because of the possible complications. Transcranial Doppler (TCD) is a non-invasive, safe method which gives accurate information about blood-flow velocities in basal cerebral arteries and indirectly about the ICP. Moreover it is inexpensive and simple in use. We report the use of TCD for middle cerebral flow velocity monitoring in a patient with a VPS who underwent laparoscopic surgery. In the case we present, during 60 min of pneumoperitoneum, TCD showed a sustained, but not clinically significant increase of the Pulsatility Index, with a recorded maximum change of 31 %. We consider that the use of TCD may increase the safety of laparoscopic procedures in patients with preexisting VPS.

Anaesthesia preference, neuraxial vs general, and outcome after caesarean section.

We investigated parturients' preference for neuraxial vs general anaesthesia, while they have experienced both techniques in the past. A total of 102 parturients who underwent elective caesarean section under general or neuraxial anaesthesia at different times completed a questionnaire comparing the two techniques. According to our results, 98% vs 51% (p < 0.001) of the women saw the baby and 51% vs 29% (p = 0.003) ambulated in the neuraxial and general anaesthesia groups, respectively, within the first 24 h postoperatively. Neuraxial anaesthesia was associated with less pain assessed by the Verbal Analogue Scale (VAS) (54 ± 21 vs 72 ± 20 p < 0.001), fewer days of hospital stay (4 ± 0.5 vs 5 ± 1.5, p = 0.001) and higher satisfaction scores (77 ± 18 vs 52 ± 24, p = 0.001) vs general anaesthesia. Finally, 80% of the women would choose neuraxial anaesthesia for a future caesarean section.

Sedation in digestive endoscopy: the Athens international position statements.

BACKGROUND: Guidelines and practice standards for sedation in endoscopy have been developed by various national professional societies. No attempt has been made to assess consensus among internationally recognized experts in this field. AIM: To identify areas of consensus and dissent among international experts on a broad range of issues pertaining to the practice of sedation in digestive endoscopy. METHODS: Thirty-two position statements were reviewed during a 1 (1/2)-day meeting. Thirty-two individuals from 12 countries and four continents, representing the fields of gastroenterology, anaesthesiology and medical jurisprudence heard evidence-based presentations on each statement. Level of agreement among the experts for each statement was determined by an open poll. RESULTS: The principle recommendations included the following: (i) sedation improves patient tolerance and compliance for endoscopy, (ii) whenever possible, patients undergoing endoscopy should be offered the option of having the procedure either with or without sedation, (iii) monitoring of vital signs as well as the levels of consciousness and pain/discomfort should be performed routinely during endoscopy, and (iv) endoscopists and nurses with appropriate training can safely and effectively administer propofol to low-risk patients undergoing endoscopic procedures. CONCLUSIONS: While the standards of practice vary from country to country, there was broad agreement among participants regarding most issues pertaining to sedation during endoscopy.

How readers perceive the quality of six anesthesia journals, their editors and reviewers: a European survey.

The aim of the present study was to evaluate six anesthesia journals and academic criteria, required for the editors and reviewers, as perceived by European anesthesiologists submitted to a questionnaire. The six journals were: Acta Anaesthesiologica Scandinavica (AAS), Anesthesia and Analgesia (AN/AN), Anesthesiology (ANESTH), British Journal of Anaesthesia (BJA), Canadian Journal of Anesthesia (CJA) and European Journal of Anaesthesiology (EJA). Anesthesiologists were questioned on number of articles read per issue, preferred category of article and type of subject addressed, usefulness of supplemental issues as well as to score each journal for quality, format and color. The academic background they would require for editors and reviewers was scored as the sum of the number of their published articles, citations and manuscripts they reviewed. AN/AN, ANESTH, BJA and EJA have higher number of articles read versus the AAS and the CJA. Article quality was estimated higher for AN/AN than for AAS, CJA and EJA, higher for ANESTH than AN/AN, AAS, CJA and EJA ( p < 0.0001 for all comparisons), and higher for BJA than for AAS, CJA and EJA. ANESTH received higher scores for format than EJA, and BJA than CJA. Finally AN/AN received higher scores for format than AAS, CJA and EJA and for color when compared to AAS, CJA, and EJA. Supplemental issues were considered useful by 77.3% of the respondents. General and original articles were preferred by the respondents. The overall scores of the estimated required academic background did not differ between editors and reviewers or between the different criteria. In conclusion, the six anesthesia journals demonstrated differences in all the variables included in the questionnaire addressed to their readers. In contrast the academic background criteria for editors and reviewers as scored by the readers did not show any differences.

General versus neuraxial anaesthesia for caesarean section: impact on the duration of hospital stay.

We investigated retrospectively the duration of hospital stay of 1,619 women who received general (GA) (n = 582) or neuraxial anaesthesia (combined spinal-epidural [CSEA] (n = 614), epidural [EA] (n = 423)) for caesarean delivery over the years 2002-2005. Hospital stay was also analysed for the different obstetricians involved. Overall duration of hospital stay differed between 2002 and 2005 (p < 0.0001) but not between CSEA and EA (p = 0.460). Overall duration of hospital stay differed between neuraxial and GA group (p < 0.001). Duration of hospital stay of the GA group showed a progressive decrease between 2002 and 2005 (p = 0.002). Duration of hospital stay after neuraxial anaesthesia differed between 2002 and 2005 (p = 0.013) and among different surgeons (p < 0.001). Discharge rates from the hospital were shorter after neuraxial anaesthesia versus GA for the 3rd and 4th postoperative days (p < 0.001 and p < 0.001, respectively). Neuraxial anaesthesia for caesarean section seems to be associated with shorter duration of hospital stay than GA.

Melatonin premedication does not enhance induction of anaesthesia with sevoflurane as assessed by bispectral index monitoring.

INTRODUCTION: Exogenous melatonin has sedating and hypnotic actions. The present prospective double-blind randomised study investigated the effect of melatonin premedication on the induction of anaesthesia with sevoflurane. METHODS: 71 women of reproductive age, scheduled for a hysteroscopy, were randomised into the melatonin or the control group. 30 minutes before the induction of anaesthesia, patients in the melatonin and control groups sublingually received 9 mg of melatonin or placebo, respectively. In the operating room, patients were attached to a standard monitor and bispectral index (BIS) monitor. Anaesthesia was induced with 8 percent sevoflurane in oxygen via an anaesthetic system primed with 8 percent sevoflurane. BIS values were recorded every 30 seconds, during the first 300 seconds of sevoflurane administration. Inspired and expired sevoflurane concentrations, heart rate and oxygen saturation were also recorded at the same time intervals. Noninvasive blood pressure was recorded before and after the completion of measurements. RESULTS: BIS values (p-value is 0.725, F is 0.125, degrees of freedom [df] 1), inspired (p-value is 0.468, F is 0.535, df 1) and expired (p-value is 0.388, F is 0.756, df 1) sevoflurane concentrations, heart rate (p-values is 0.516, F is 0.427, df 1) and oxygen saturation (p-value is 0.401, F is 0.717, df 1), did not differ between the two groups, at any time point of measurement. Systolic blood pressure before (p-value is 0.131, t 1.530, df 67) and after measurement (p-value is 0.8288, t 0.218, df 54) as well as diastolic blood pressure before (p-value is 0.370, t 0.902, df 67) and after measurement (p-value is 0.764, t 0.302, df 54) did not differ between the two groups. CONCLUSION: Melatonin premedication under the present study design failed to enhance the induction of anaesthesia with sevoflurane.

A randomized study of maternal serum cytokine levels following cesarean section under general or neuraxial anesthesia.

BACKGROUND: Cytokines are significant mediators of the immune response to surgery and also play a role in parturition. The aim of the study was to investigate the impact of the anesthetic technique for cesarean section on plasma levels of cytokines IL-6 and TNF-alpha. METHODS: Thirty-five parturients scheduled for elective cesarean section were randomly assigned to general (n=18) or neuraxial (n=17) anesthesia. The general anesthesia group received thiopental 4 mg/kg, succinylcholine 1-1.5 mg/kg and 1% end-tidal concentration of sevoflurane in nitrous oxide and 50% oxygen. The neuraxial anesthesia group received intrathecal 0.5% levobupivacaine 1.8-2.2 mL and epidural fentanyl 1 microg/kg. Blood samples were taken for IL-6 and TNF-alpha immediately after positioning the parturient on the operating table, after uterine incision and before the umbilical cord clamping and 24h after surgery (T(1), T(2) and T(3) respectively). RESULTS: The two groups did not differ in IL-6 (P=0.15) or TNF-alpha (P=0.73) serum concentrations at any time point. In the general and neuraxial anesthesia groups, IL-6 serum concentrations were significantly higher in the third blood sample, T(3) (12.2+/-5.0 and 15.2+/-4.3 pg/mL), than in T(1) (0.41+/-0.38 and 0.29+/-0.10 pg/mL) and T(2) (0.37+/-0.47 and 0.24+/-0.05) respectively (P<0.001). Within each group, serum TNF-alpha concentrations did not differ significantly over time (P=0.44). CONCLUSIONS: Under the present study design anesthetic technique did not affect IL-6 or TNF-alpha concentrations in parturients undergoing elective cesarean section. Serum IL-6 levels increased 24 h postoperatively independently of anesthetic technique.

Acute postoperative pain predicts chronic pain and long-term analgesic requirements after breast surgery for cancer.

Postoperative pain and analgesic requirements may be associated with chronic pain. The aim of the study was to investigate this association. We studied 98 patients who had cancer breast surgery and served as controls in four previous studies, receiving placebo. We compared the pain and analgesic requirements 0-9 h and 1-6 days postoperatively: a) between patients with chronic pain 3 months postoperatively versus patients without and b) between those patients who consumed analgesics at home versus those who did not. Patients with chronic pain had experienced higher intensity pain at rest the first 9 postoperative hours (VAS-rest p = 0.033). Patients requiring analgesics at home had consumed postoperatively more opioids (p = 0.005) and more paracetamol (p = 0.037). These patients had experienced pain of higher intensity the first 9 postoperative hours (VAS-rest p = 0.022, VAS-movement p = 0.009) as well as during the six postoperative days (VAS-rest p = 0.013, VAS-movement p = 0.001). Higher intensities of acute postoperative pain are associated with chronic pain development. Higher analgesic needs and higher acute postoperatively pain intensity are associated with long-term analgesic consumption.

Local application of halothane, isoflurane or sevoflurane increases the response to an electrical stimulus in humans.

UNLABELLED: Volatile anesthetics may interfere with pain perception. This study investigates the effect of halothane, isoflurane and sevoflurane when applied locally, to the response of an electrical stimulus. METHODS: In this randomized control double-blind crossover study 70 volunteers were studied. In experiment 1 (30 subjects), equipotent liquid volumes of halothane 1 ml, isoflurane 1.5 ml and sevoflurane 2.7 ml were randomly applied on one forearm for 30 minutes. The other forearm received water. Both forearms were exposed to an electrical stimulus. The experiment was repeated the following day in a reverse fashion. In experiments 2 (20 subjects) and 3 (20 subjects) the response to the same stimulus was tested after local application of 2, 4, and 6 ml of halothane or 5 ml of sevoflurane respectively. RESULTS: Low doses of the three anesthetics were associated with an increased response to the electrical stimulus (F = 8.940, df = 1,174, P = 0.003). Higher doses of halothane and sevoflurane had no effect on the response (F = 2.358, df = 1,114, P = 0.127 and t = 0.840, df = 19, P = 0.411 respectively). CONCLUSIONS: Low liquid volumes of volatile anesthetics, when applied locally to the skin enhanced the response to an electrical stimulus but higher volumes had no effect.

A combination of gabapentin and local anaesthetics attenuates acute and late pain after abdominal hysterectomy.

BACKGROUND AND OBJECTIVE: Gabapentin and local anaesthetics may decrease postoperative pain and analgesic needs. The aim of the study was to investigate the effect of the combination of these drugs on the analgesic needs as well as on acute and late pain after abdominal hysterectomy. METHODS: Sixty patients undergoing abdominal hysterectomy were randomly assigned to receive postoperatively oral gabapentin 400 mg 6 hourly for 7 days plus continuous wound infusion of ropivacaine 0.75% for 30 h or placebo capsules identical to those of gabapentin for 7 days and continuous wound infusion of normal saline for 30 h. Morphine consumption (PCA) for 48 h, paracetamol 500 mg plus codeine 30 mg (Lonalgal tablets) intake on days 3-7, visual analogue pain scores at rest and after cough during the first 7 postoperative days, the need for analgesics at home and the presence and incidence of pain after 1 month were recorded. RESULTS: The treatment group consumed less cumulative morphine over the first 48 h (31 +/- 13.2 mg vs. 50 +/- 20.5 mg in controls, P < 0.001) and less Lonalgal tablets on days 3-7 (z = 2.54, P = 0.011). The visual analogue score values at rest and after cough did not differ between the groups during the first 7 postoperative days. One month postoperatively, fewer patients in the treatment group experienced pain due to surgery than in the control group (17/27 vs. 21/24, P = 0.045). CONCLUSION: Gabapentin and continuous wound infusion with ropivacaine 0.75% decreased analgesic needs and late pain in patients undergoing abdominal hysterectomy.

Responses to mechanical and electrical stimuli are not attenuated by late pregnancy.

Pregnancy has been associated with increased pain threshold. This study investigates the responses to mechanical and electrical stimuli in pregnant and non-pregnant women. Thirty pregnant women were subjected before and four days after elective caesarean section under regional anaesthesia to mechanical and electrical stimuli on both forearms. Thirty nonpregnant women were subjected to the same stimuli at the same time points. The responses to mechanical stimuli were expressed in mm of the Visual Analogue Scale (VAS) and averaged for both forearms. The VAS scores obtained after the electrical stimuli were divided by the mA recorded when the stimulus was applied, expressed in mm/mA and averaged. The responses to mechanical stimuli recorded before and four days after application did not differ between the two groups (F = 0.884, df = 3,116, P = 0.452). In the pregnant group the VAS values before and four days after the caesarean section were 16.4 +/- 14.4 mm and 12.8 +/- 12.5 mm respectively. In the nonpregnant group the VAS values recorded four days apart were 17.5 +/- 14.3 mm and 13.4 +/- 11.9 mm respectively. The responses to electrical stimuli applied four days apart also did not differ between the two groups (F = 2.433, df = 3,116, P = 0.069). The VAS values obtained after the first and second application of the electrical stimulus were 0.914 +/- 0.606 mm/mA versus 0.586 +/- 0.410 mm/mA in the pregnant and 0.853 +/- 0.538 mm/mA versus 0.725 +/- 0.467 mm/mA in the nonpregnant group. These results, under the study conditions, do not support the hypothesis that late pregnancy is associated with increased antinociception in humans.

Sevoflurane as a single anesthetic and physostigmine failure to enhance arousal.

AIM: Sevoflurane is recommended for inhalational induction of anesthesia. Physostigmine may antagonize general anesthetics. The study investigates sevoflurane as a single anesthetic and its possible antagonism by physostigmine. METHODS: In 60 women scheduled for breast lump excision, anesthesia was induced with 8% sevoflurane. After 3 min of sevoflurane inhalation, a laryngeal mask airway (LMA) was inserted. Anesthesia was maintained with spontaneous ventilation at end tidal sevoflurane 3%. Systolic and diastolic blood pressure, heart rate and end tidal CO(2) were recorded intraoperatively. After skin closure and at end tidal sevoflurane 0.9%, physostigmine 2 mg or normal saline was given. After 2 min systolic, diastolic blood pressure, heart rate and end tidal CO(2) were recorded and sevoflurane was discontinued. Time to eyes opening, LMA removal and verbal response was recorded. Patients were also assessed for orientation, sedation, sitting ability and the ''picking up matches'' test at 0, 15 and 30 min after LMA removal. RESULTS: Systolic, diastolic blood pressure and heart rate increased after laryngeal mask placement (P=0.0001, P=0.0001 and P=0.0001, respectively). Orientation, sitting ability and ''picking up'' matches were similar in the 2 groups. Sedation at 15 min was less in the control group (P=0.004). CONCLUSIONS: Sevoflurane can be used as a single anesthetic but its recovery is not enhanced by physostigmine.

Gabapentin attenuates the pressor response to direct laryngoscopy and tracheal intubation.

BACKGROUND: Laryngoscopy and tracheal intubation increase blood pressure and heart rate (HR). The aim of the present study was to investigate the effect of gabapentin when given before operation on the haemodynamic responses to laryngoscopy and intubation. METHODS: Forty-six patients undergoing abdominal hysterectomy for benign disease were randomly allocated to receive gabapentin 1,600 mg or placebo capsules at 6 hourly intervals starting the day (noon) before surgery. Anaesthesia was induced with propofol and cis-atracurium. Systolic, diastolic arterial blood pressures (SAP, DAP) and heart rate (HR) were recorded before and after the anaesthetic and 0, 1, 3, 5 and 10 min after tracheal intubation. RESULTS: SAP was significantly lower in the gabapentin vs the control group 0, 1, 3, 5 and 10 min after intubation [128 (27) vs 165 (41), P=0.001, 121 (14) vs 148 (29), P=0.0001, 115 (13) vs 134 (24), P=0.002, 111 (12) vs 126 (19), P=0.004 and 108 (12) vs 124 (17), P=0.001 respectively]. DAP also was lower in the gabapentin group 0, 1, 3, and 10 min after intubation [81 (18) vs 104 (19), P=0.0001, 77 (9) vs 91 (16), P=0.001, 71 (10) vs 84 (13), P=0.001 and 67 (10) vs 79 (12), P=0.004]. HR did not differ between the two groups at any time [82 (11) vs 83 (15), 79 (10) vs 80 (12), 86 (17) vs 92 (10), 82 (11) vs 88 (10), 81 (12) vs 81 (11), 77 (13) vs 79 (13), and 75 (15) vs 78 (12)]. CONCLUSION: Gabapentin, under the present study design attenuates the pressor response but not the tachycardia associated with laryngoscopy and tracheal intubation.