Ethylene oxide allergy in patients on hemodialysis waiting for kidney transplantation: logistical nightmare or challenge? A case report.

Ethylene oxide (EO) is widely used as a sterilization gas for heat-sensitive devices. In EO-sensitized patients, this type of sterilization can cause rare but major allergic reactions such as hives, rash, asthma, or anaphylactic shock. Hemodialysis patients in particular are at risk of developing hypersensitivity to EO. In these patients, surgical interventions should be planned far in advance allowing a thorough EO-free preparation of all equipment needed for the surgery as well as for the pre-, peri-, and postoperative care. In contrast to elective surgery, kidney transplantation with allografts from deceased donors cannot be planned; exact timing is unpredictable. Furthermore, transplantation may take place years after patients have been put on the waiting list. Listing of patients sensitive for EO is therefore a logistical and medical challenge for all health care professionals involved in the patient's care (eg, surgeons, nephrologists, anesthetists, nurses, pharmacists, and sterilization specialists). This case report describes a patient with chronic kidney disease stage V who developed EO allergy during hemodialysis while waiting for a kidney transplantation. Diagnosis was made based on clinical signs and confirmed biochemically (including a positive radioallergosorbent test). Because the only treatment is avoidance of contact with EO-sterilized materials, a strict EO-free protocol was developed to allow an uneventful transplantation thereafter. Subsequently, 4 newly diagnosed EO-sensitive patients on the active kidney transplantation waiting list were diagnosed, and 1 of these patients has been transplanted successfully. EO allergy in patients on the waiting list for kidney transplantation is a unique challenging situation which, to the best of our knowledge, has not been reported yet for kidney transplantation. This report further highlights the logistical preparation of a renal transplantation, including anesthesiologic, surgical, and postoperative care.

Effects of epidural clonidine and neostigmine following intrathecal labour analgesia: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: The limited duration of spinal labour analgesia combined with problems associated with maintenance of epidural analgesia, have prompted the search for combinations that could prolong spinal analgesia. A randomised, double-blind trial was carried out to test the hypotheses (a) that initial spinal labour analgesia is prolonged by administering clonidine and neostigmine epidurally whilst (b) the hourly local anaesthetic consumption is reduced. METHODS: Seventy labouring patients received spinal analgesia with ropivacaine and sufentanil. Fifteen minutes after spinal injection, 10 mL of study solution was administered epidurally. The study solution was plain saline or neostigmine 500 microg combined with clonidine 75 microg. Outcome parameters were duration of spinal analgesia, local anaesthetic consumption and number of patients delivering without additional epidural analgesia. RESULTS: Epidural clonidine and neostigmine significantly prolonged initial analgesia: 144 (105-163) min vs. 95 (70-120) min in the placebo group and reduced hourly ropivacaine consumption: 7.5 (3.0-11.9) mg vs. 12.7 (9.6-16.9) mg. More patients in the experimental group delivered before the first request for additional analgesia (9 vs. 2). CONCLUSION: Epidural administration of neostigmine 500 microg and clonidine 75 microg, following the intrathecal injection of ropivacaine and sufentanil, prolongs analgesia and reduces hourly ropivacaine consumption.

Pulmonary gas exchange is well preserved during robot assisted surgery in steep Trendelenburg position.

INTRODUCTION: During robot assisted hysterectomies and prostatectomies, surgical exposure demands the application of a CO2 pneumoperitoneum with a very steep Trendelenburg position (40 degrees). The extent to which oxygenation and ventilation might be compromised intra-operatively remains poorly documented. METHODS: Dead-space ventilation and venous admixture were determined in 18 patients undergoing robot assisted hysterectomy (n = 6) or prostatectomy (n = 12). Anesthesia was maintained with desflurane in O2 or O2/air, with the inspired O2 fraction left at the discretion of the attending anesthesiologist. Controlled mechanical ventilation was used, but 15 min after assuming the Trendelenburg position and up until resuming the supine position pressure controlled ventilation was used. Dead-space ventilation and venous admixture were determined using Bohr's formula and Nunn's iso-shunt diagram, respectively, at the following 7 stages of the procedure: 15 min after induction; 5 min after applying the CO2 pneumoperitoneum (intra-abdominal pressure 12 mm Hg) but while still supine; 5, 60, and 120 min after assuming the Trendelenburg positioning; and 5 and 15 min after reassuming the supine position. RESULTS: Venous admixture did not change. Dead-space ventilation increased after Trendelenburg positioning, and returned to baseline values after resuming the supine position. However, individual patterns varied widely. DISCUSSION: The lung has a remarkable yet incompletely understood capacity to withstand the effects of a CO2 pneumoperitoneum and steep Trendelenburg position during general anesthesia. While individual responses vary and should be monitored, effects on dead-space ventilation and venous admixture are small and should not be an obstacle to provide optimal surgical exposure during robot assisted prostatectomy or hysterectomy.

Ten years of experience with accidental dural puncture and post-dural puncture headache in a tertiary obstetric anaesthesia department.

BACKGROUND: Accidental dural puncture (ADP) and post-dural puncture headache (PDPH) are important complications of obstetric regional anaesthesia. METHODS: Between January 1997 and October 2006 in our tertiary obstetric referral centre 17 198 neuraxial blocks were recorded; 965 epidural, 16193 combined spinal-epidural and 40 spinal. Records of all parturients who experienced either ADP or PDPH were reviewed. RESULTS: There were 89 ADPs (0.5%), 55 observed and 34 in which PDPH followed unrecognised dural puncture. Following known ADP, 28 women had epidural catheters re-sited at a different lumbar interspace and 27 had intrathecal catheters for at least 24 h. Thirty-one women developed PDPH after observed ADP; the incidence of PDPH was similar after puncture with needle and catheter, after epidural and CSE techniques, after 27- and 29-gauge pencil-point spinal needles and after spinal and epidural catheter insertion (61% vs 52%; P>0.05). All headaches presented within 72 h. A blood patch was needed in 26/55 women after known ADP and 27/34 unrecognised ADP. A repeat blood patch was needed in 8 (15%). DISCUSSION: The incidence of ADP, PDPH, blood patching and repeat blood patching is similar to previous studies. Many ADPs are unrecognised during epidural insertion. CSE does not appear to increase the risk of ADP or PDPH; 29-gauge rather than 27-gauge pencil-point spinal needles conferred no benefit. Inserting the epidural catheter intrathecally did not significantly reduce the incidence of PDPH and blood patching in our series.

Prevention of postoperative hypotension following spinal anesthesia for TURP: a double-blind randomized controlled trial comparing ephedrine with placebo.

Spinal hypotension (SH) is a common side effect of spinal anesthesia and may also occur after the surgical procedure. In this double-blinded, placebo-controlled, randomised clinical trial fifty patients undergoing transurethral prostatectomy under spinal anesthesia received 10 mg of ephedrine IV before being transferred from the operating table into their bed after the procedure, whereas fifty controls received saline IV. The number of per- and postoperative hypotensive episodes and vasopressor use, time delay between the administration of the study medication and the first hypotensive episode, level of spinal blockade at the start of surgery, pre- and postoperative hemoglobine and sodium concentration, cardiovascular co-morbidity and chronic medication were registered. There was no statistically significant difference in the incidence of postoperative hypotension between the two groups, but Poisson regression of the expected number of postoperative hypotensive episodes per patient showed a protective effect of ephedrine (p < 0.05). The occurence of peroperative hypotension was a risk factor for developing postoperative hypotension (p < 0.05). There was no statistically significant relation between age, level of spinal blockade, cardiovascular co-morbidity or biochemical parameters and the risk of developing per- or postoperative hypotension, except for a correlation between preoperative alpha-receptor blocking drugs and peroperative hypotension (p < 0.05). Postoperative hypotension (recorded incidence 31%) was almost as common as peroperative hypotension (recorded incidence 37%) and occurred as late as 190 minutes after the end of surgery. Ephedrine IV at the end of surgery reduced the number of postoperative hypotensive episodes per patient but did not reduce the overall incidence of postoperative SH.

Effect of sufentanil on minimum local analgesic concentrations of epidural bupivacaine, ropivacaine and levobupivacaine in nullipara in early labour.

BACKGROUND: The aim was to assess the effect of epidural sufentanil on relative analgesic potencies of epidural bupivacaine, ropivacaine and levobupivacaine by determining the minimum local analgesic concentrations during labour. METHODS: In a randomised, double-blind study, 171 parturients were allocated to one of six groups receiving a 10-mL bolus of bupivacaine, ropivacaine or levobupivacaine alone or with sufentanil 0.75 microg/mL. The concentration of local anaesthetic was determined by the response of the previous parturient using up-down sequential allocation starting at a concentration of 0.13% wt/vol with a testing interval of 0.01%. Effective analgesia was defined as a visual analogue pain score < or = 15/100 mm within 30 min and lasting for 30 min. Median effective concentrations were estimated and two-sided P < 0.05 was significant. RESULTS: Local anaesthetic concentration, use of sufentanil and local anaesthetic drug were independent significant predictors of effective and ineffective analgesia. Bupivacaine was significantly more potent than levobupivacaine and ropivacaine. The relative potency ratios without sufentanil of 0.77:0.83:1.00 were reduced to 0.36:0.38:1.00 by the addition of sufentanil. The major factor influencing local anaesthetic requirements was the addition of sufentanil, which reduced overall requirements by a factor of 4.2 (95% CI 3.6-4.8); this effect was proportionately more enhanced for bupivacaine. CONCLUSIONS: Local anaesthetic requirements for bupivacaine, levobupivacaine and ropivacaine follow an analgesic potency hierarchy. Any potency differences are small when compared to the effect of sufentanil, which resulted in a four-fold reduction in local anaesthetic requirements. Sufentanil may also enhance the potency differences between bupivacaine and the two S-enantiomer agents.

Acute pulmonary hypertension causes depression of left ventricular contractility and relaxation.

BACKGROUND AND OBJECTIVE: The haemodynamic effects of acute pulmonary hypertension can be largely attributed to ventricular interdependence during diastole. However, there is evidence that the two ventricles also interact during systole. The aim of the present study was to examine the effects of acute pulmonary hypertension on both components of left ventricular systole, i.e. contraction and relaxation, using load-independent indices. METHODS: Ten pigs were instrumented with biventricular conductance catheters, a pulmonary artery flow probe and a high-fidelity pulmonary pressure catheter. Haemodynamic measurements were performed in baseline conditions and during stable pulmonary vasoconstriction induced by the thromboxane analogue U46619. Contractility was quantified using the end-systolic pressure-volume and preload recruitable stroke work relationships. The tau-end-systolic pressure relationship was used to assess load-dependency of relaxation. RESULTS: Acute pulmonary hypertension caused a decrease in the slope of the left ventricular preload recruitable stroke work relationship (from 6.64 +/- 1.7 to 5.19 +/- 1.9, mean +/- SD; P < 0.05), a rightward shift of the end-systolic pressure-volume relationship (P < 0.05), and an increase in the slope of the tau-end-systolic pressure relationship (from -0.15 +/- 0.5 to 0.35 +/- 0.17; P < 0.05). The diastolic chamber stiffness constant of both ventricles increased during pulmonary hypertension (P < 0.05). CONCLUSIONS: In the present model, acute pulmonary hypertension impairs left ventricular contractile function and relaxing properties. The present study provides additional evidence that, besides the well-known diastolic ventricular cross talk, systolic ventricular interaction may play a significant role in the haemodynamic consequences of acute pulmonary hypertension.

Patient-controlled epidural analgesia following combined spinal-epidural analgesia in labour: the effects of adding a continuous epidural infusion.

Patient-controlled epidural analgesia (PCEA) is used to maintain epidural analgesia following initial intrathecal analgesia. This trial investigated whether a continuous background infusion with PCEA provides superior analgesia to PCEA alone among patients who received combined spinal-epidural (CSE) analgesia during labour Eighty parturients were randomized to either PCEA alone (PCEA) or PCEA with a background infusion of ropivacaine 0.15% with sufentanil 0.75 microg/ml at 2 ml/h (PCEA + CEI). PCEA settings were a bolus of 4 ml of the same analgesic solution with a lockout interval of 15 minutes. Significantly more patients in the PCEA group required at least one anaesthetist intervention for breakthrough pain (27 [71%] vs 10 [25%] in the PCEA + CEI group, P<0.05). Consumption of local anaesthetic (excluding manually administered boluses) was similar between the groups. If anaesthetist-administered boluses were included, more local anaesthetic was consumed by the PCEA group (47.1 +/- 19.4 mg vs 35.6 +/- 12.0 mg in the PCEA + CEI group, P<0.05). We conclude that PCEA with a background infusion provides effective analgesia with less anaesthetist workload and reduced local anaesthetic consumption as compared with PCEA without a background infusion.

A randomized trial comparing low-dose combined spinal-epidural anesthesia and conventional epidural anesthesia for cesarean section in severe preeclampsia.

BACKGROUND AND OBJECTIVES: A prospective, randomized study was designed to compare the maternal and neonatal effects of conventional epidural anesthesia and combined spinal epidural anesthesia (CSE) for Cesarean section in severe preeclamptic patients. Additionally, two strategies in the prophylactic management of hypotension in severe preeclamptic patients were evaluated: fluid preloading or prophylactic ephedrine. METHODS: Thirty nonlaboring women with severe preeclampsia (PET), scheduled for an elective Cesarean section, were randomised into three groups: epidural anesthesia with prophylactic fluid loading (EA-F), combined spinal epidural anesthesia with prophylactic fluid loading (CSE-F), or combined spinal epidural anesthesia with prophylactic ephedrine (CSE-V). Hemodynamic data were recorded prior and after induction of regional anesthesia at five-minute intervals. The total amount of intravenous administered fluid and the total dose of vasopressors were recorded. RESULTS: Hemodynamic data were similar between the three groups. The incidence and duration of hypotension was similar in all three groups. Significantly more ephedrine was used in the CSE-V group as compared to the CSE-F group. More lactated Ringer's solution was used in the CSE-F group as compared to the CSE-V group. There were no hypertensive episodes and none of the patients developed pulmonary edema. The time period from induction until the start of surgery and the duration of surgery were significantly shorter in both CSE-groups. Neonatal outcome was comparable between the three groups. CONCLUSION: Our results confirm that combined spinal and epidural anesthesia (CSE) is a safe alternative to conventional epidural anesthesia in severe preeclamptic women and that the prophylactic use of ephedrine is effective and safe to prevent and treat spinal hypotension after combined spinal and epidural anesthesia for Cesarean section in severe preeclamptic women.

General anaesthesia with target controlled infusion of propofol for planned caesarean section: maternal and neonatal effects of a remifentanil-based technique.

The present case series evaluated maternal and neonatal effects of remifentanil, combined with propofol, during general anaesthesia for caesarean delivery. Following written informed consent, ten patients scheduled for semi-elective caesarean section were recruited to this prospective, unblinded trial. All patients with non-reassuring fetal status were excluded. A 0.50-micrograms/kg bolus of remifentanil was given intravenously, followed by a continuous infusion of 0.20 micrograms.kg(-1)min(-1). Anaesthesia was induced using propofol target controlled infusion set at a blood concentration of 5 micrograms/mL, 45 s after the remifentanil bolus. Following tracheal intubation the propofol target was reduced to 2.5 micrograms/mL and remifentanil maintained at 0.20 micrograms.kg(-1)min(-1). Mean arterial pressure remained stable throughout anaesthesia. Two patients experienced episodes of hypotension (mean arterial pressure decrease >20%). Although neonatal depression occurred in six babies and assisted mask ventilation was required briefly, recovery was rapid without the need for naloxone or tracheal intubation. Umbilical artery pH was >7.20 in all infants. We conclude that the results of the present case series using a remifentanil/propofol-based technique of general anaesthesia for caesarean section provide a basis to study the safety of this technique in a larger population. Under the conditions of the present trial, this anaesthetic technique seems safe for mother and infant, provided adequate precautions are taken to manage brief, self-limiting infant respiratory depression. At the moment we cannot advise the routine use of this technique, especially since it has not been studied in situations of fetal compromise.

Low-dose combined spinal-epidural anaesthesia vs. conventional epidural anaesthesia for Caesarean section in pre-eclampsia: a retrospective analysis.

BACKGROUND AND OBJECTIVE: Epidural anaesthesia is the preferred technique of anaesthesia for Caesarean section in pre-eclampsia. Spinal anaesthesia is considered by some as a safe and effective alternative, which is especially useful in emergency situations. Combined spinal-epidural anaesthesia, using low doses of local anaesthetics with opioids, is effective and reduces the incidence of hypotension in normal pregnancy. We performed a retrospective chart analysis to evaluate the effects of combined spinal-epidural anaesthesia on maternal haemodynamics and fetal outcome compared to conventional epidural anaesthesia. METHODS: A retrospective anaesthesia chart analysis of all pre-eclamptic patients who underwent Caesarean section over a 4 yr period was performed. Patient characteristic, obstetric, haemodynamic, fetal and neonatal data were gathered and analysed according to the anaesthetic technique used. RESULTS: Seventy-seven pre-eclamptic parturients undergoing Caesarean section were identified (26 women were severely pre-eclamptic and 51 demonstrated mild pre-eclampsia). Epidural anaesthesia was performed in 62 patients and combined spinal-epidural anaesthesia was performed in 15. No differences in patient characteristic and obstetric data were noted. Highest mean arterial pressure prior to anaesthesia was comparable between the groups (epidural: 106 +/- 12 vs. combined spinal-epidural anaesthesia: 109 +/- 18 mmHg) as well as the lowest recorded mean arterial pressure following anaesthesia (epidural: 93 +/- 13 vs. combined spinal-epidural anaesthesia: 98 +/- 17 mmHg). In the combined spinal-epidural anaesthesia group more ephedrine was used compared to the epidural group (14.6 +/- 4.4 vs. 3.6 +/- 4.6 mg, P < 0.05). However, more lactated Ringer's was used in the epidural group. Umbilical artery pH was lower in the epidural group (7.26 +/- 0.01 vs. 7.29 +/- 0.02, P < 0.05). Similar results were noted in 26 severely pre-eclamptic patients. Seven women underwent combined spinal-epidural anaesthesia and 19 underwent epidural anaesthesia in the severely pre-eclamptic group. Also more ephedrine was used in the combined spinal-epidural anaesthesia group. A tendency towards a lower umbilical artery pH was observed in the epidural group but this difference did not reach statistical significance. CONCLUSIONS: Combined spinal-epidural anaesthesia appears to be safe as anaesthetic technique for pre-eclampsia and severe pre-eclampsia. However, it is important to consider the retrospective design of the study and the large number of epidural anaesthetics performed.

Evaluation of the neuroprotective effects of S(+)-ketamine during open-heart surgery.

UNLABELLED: We compared the effect of S(+)-ketamine to remifentanil, both in combination with propofol, on the neurocognitive outcome after open-heart surgery in 106 patients. A battery of neurocognitive tests was administered before surgery and 1 and 10 wk after surgery. Fourteen patients (25%) in the control group and 10 patients (20%) in the S(+)-ketamine group had 2 or more tests with a cognitive deficit (decline by at least one preoperative SD of that test in all patients) 10 wk after surgery (P = 0.54). Z-scores were calculated for all tests. No significantly better performance could be detected in the S(+)-ketamine group, except for the Trailmaking B test 10 wk after surgery. We conclude that S(+)-ketamine offers no greater neuroprotection compared with remifentanil during open-heart surgery. IMPLICATIONS: N-methyl-D-aspartic acid receptors play an important role during ischemic brain injury. We could not demonstrate that S(+)-ketamine resulted in greater neuroprotective effects compared with remifentanil during cardiopulmonary bypass procedures when both were combined with propofol.

Intrathecal sufentanil and fetal heart rate abnormalities: a double-blind, double placebo-controlled trial comparing two forms of combined spinal epidural analgesia with epidural analgesia in labor.

UNLABELLED: Combined spinal epidural analgesia (CSE) for labor pain relief has become increasingly popular. However, the effect of intrathecal sufentanil on the incidence of uterine hyperactivity and fetal heart rate (FHR) abnormalities remains controversial. We hypothesized that the use of intrathecal sufentanil in a dose of 7.5 microg is more likely to induce a nonreassuring FHR tracing than a small dose of spinal sufentanil combined with bupivacaine or epidural analgesia. Three-hundred parturients were randomized into three groups. In the first group, epidural analgesia was initiated with 12.5 mg of bupivacaine, 12.5 microg of epinephrine, and 7.5 microg of sufentanil in a volume of 10 mL (EPD group). In Group 2, initial intrathecal analgesia consisted of 2.5 mg of bupivacaine, 2.5 microg of epinephrine, and 1.5 microg of sufentanil (BSE group); in Group 3, spinal analgesia consisted of 7.5 microg of sufentanil (SUF group). Analgesia was maintained in all groups with patient-controlled epidural analgesia using bupivacaine 0.125%, 1.25 microg/mL of epinephrine, and 0.75 microg/mL of sufentanil (bolus, 4 mL; lockout, 15 min). Cardiotocography was monitored continuously 15 min before analgesia and for 60 min after the start of analgesia. The quality of analgesia, labor, and neonatal outcome and side effects were recorded. Twenty-four percent of patients in the SUF group developed FHR abnormalities (bradycardia or late decelerations) during the first hour after initiation of analgesia compared with 12% in the BSE group and 11% in the EPD group. Uterine hyperactivity occurred in 12% of parturients in the SUF group but in only 2% in the other groups. Onset of analgesia was more rapid in both CSE groups as compared with the EPD group. However, 29% of patients in the BSE group developed severe hypotension, requiring IV ephedrine (29% in the BSE group versus 7% and 12% in the EPD and SUF groups, respectively). All these differences reached statistical significance. The present data corroborate previous recommendations of caution when performing CSE using a large dose (7.5 microg or more) of spinal sufentanil because of the risk of uterine hyperactivity and FHR abnormalities. IMPLICATIONS: Combined spinal epidural analgesia (CSE) produces pain relief during labor. Fetal heart rate changes after CSE using intrathecal sufentanil have been reported. We performed a randomized, blinded trial confirming that fetal heart rate changes are more frequent after CSE using 7.5 micro g of intrathecal sufentanil as compared with other forms of neuraxial labor analgesia.

Evaluation of a new continuous cardiac output monitor in off-pump coronary artery surgery.

We evaluated a new, ultra-fast response continuous cardiac output monitor in 34 adult patients undergoing off-pump coronary artery bypass graft surgery. Cardiac output was measured with the TruCCOMS continuous cardiac output monitor (Aortech International plc, Lanarkshire, UK), using triplicate cold bolus thermodilution as the criterion standard, at fixed time points during surgery and during dobutamine infusion. The two techniques were compared using linear regression and Bland-Altman analysis. Overall, the study device displayed a bias of 0.4 l.min(-1) with limits of agreement of +2.5 l.min(-1) and -1.7 l.min(-1). The study device failed to detect the change in cardiac output caused by dobutamine accurately (y = 0.18x + 0.45; r(2) = 0.13), with an error linearly related to the magnitude of the change measured. We conclude that the device's failure to detect changes in cardiac output could be a major limitation in its clinical use in its current form.

Continuous spinal analgesia for labor pain in a parturient with aortic stenosis.

Aortic stenosis in pregnancy carries a high fetal and maternal morbidity and mortality. Spinal analgesia/anesthesia is considered by many to be contraindicated in these patients. The rapid onset of sympathetic block induces hypotension, which can result in myocardial hypoperfusion and myocardial ischemia. We describe a case of moderate to severe aortic stenosis, diagnosed during pregnancy, in which pain relief during labor and delivery was managed using a continuous spinal catheter. Pure intrathecal opioid analgesia was used initially to maintain hemodynamic stability. However after two bolus administrations of sufentanil, analgesia was further maintained using ropivacaine and sufentanil. A spinal catheter was chosen to provide reliable anesthesia, which could be extended rapidly for cesarean section.