The effect of the volume of supra-inguinal injected solution on the spread of the injectate under the fascia iliaca: a preliminary study.

The fascia iliaca compartment is the compartment confined by the fascia iliaca (FI) and a muscular layer formed by the iliac- and psoas muscle. This compartment creates a virtual tunnel that contains the femoral nerve (FN), the obturator nerve (ON), and the lateral femoral cutaneous nerve (LFCN) of the lumbar plexus. In this pilot study, we aimed to determine the suggested volume needed to reach the three target nerves of the lumbar plexus (FN, ON, and LFCN) with a single-injection ultrasound-guided supra-inguinal fascia iliaca compartment (S-FICB). A computer tomography (CT scan)-guided step-up/step-down sequence was used to determine the suggested injection volume to target all three nerves. Subsequently, an anatomist blinded for the injected volume and CT findings, dissected the cadavers, and evaluated the spread of dye underneath the fascia iliaca. In total, seven pelvic areas of four cadavers were evaluated on CT scan and dissected. Distribution of dye underneath the FI in relation to the FN, ON, and the LFCN was recorded in all dissected cadavers. Combining CT and dissection findings, the suggested volume to reach the FN, ON, and LFCN with an S-FICB was 40 mL.

Allergic reactions during labour analgesia and caesarean section anaesthesia.

Allergic reactions in the parturient are challenging for the anaesthetist who is dealing with both mother and baby, often in circumstances when there is a need for delivery. While most previous reviews have focused on specific substances in individual cases, this review focuses on allergic reactions during the peripartum period, the differential diagnosis and specific treatment options. Immunoregulation and susceptibility to allergic reactions may change during pregnancy. Compared with non-pregnant patients, in whom neuromuscular blocking drugs are the most common triggering substances, allergic reactions in parturients mostly occur following contact with latex, injection of antibiotics and uterotonics, and infusion of colloids. With the exception of latex, where patient history may raise suspicion, allergic reactions may occur without prior exposure to triggering agents. Most drugs used for resuscitation of the non-pregnant patient are suitable for the parturient. Some substances, such as H2-receptor antagonists for aspiration prophylaxis or corticosteroids for prematurity, may have been given before the event. Although fetal outcome is important, the mother is the primary focus of care.

Supraclavicular brachial plexus blocks: review and current practice.

This article reviews the possible revival of the supraclavicular brachial plexus blockade due to the use of ultrasound guidance. The brachial plexus is a complex network of nerves, extending from the neck to the axilla, which supplies motor and sensory fibers to the upper extremity. Understanding the complexities of the formation and structure of the brachial plexus remains a cornerstone for effective regional anaesthesia. On the level of the supraclavicular fossa, the plexus is most compactly arranged. The supraclavicular approach of the brachial plexus has a high success rate including blockade of the ulnar and musculocutaneous nerve, which can be missed respectively with the interscalene and axillary approach. However, because of the proximity of the pleura, most anaesthesiologists have been reluctant to perform this supraclavicular approach. The introduction of ultrasound guidance techniques not only reduces the possible risk of pneumothorax but also allows a faster onset time of the block with a reduction of the local anaesthetic dose. This makes the supraclavicular approach a valuable alternative to the axillary, interscalene and infraclavicular approach for upper limb surgery.

Timing of skin testing after a suspected anaphylactic reaction during anaesthesia.

BACKGROUND: A delay of 4 to 6 weeks after a suspected anaphylactic reaction has commonly been recommended before performing skin testing. However, sometimes surgery cannot be delayed, and investigation must be done earlier. Recent recommendations suggest that skin testing can be performed immediately after a reaction. METHODS: We describe three cases in which skin testing was performed within 3 weeks after the suspected anaphylactic reaction. A literature review was undertaken to evaluate cases where skin testing was performed within 3 weeks of a suspected anaphylactic reaction during anaesthesia. RESULTS: Review of the literature did not give a definite answer to the optimal timing of skin testing after a suspected anaphylactic reaction during anaesthesia. CONCLUSIONS: Only positive skin tests can be taken into account, and there is little safety data to provide confidence in early skin testing. A protocol of how to act if urgent surgery is necessary is suggested.

Anaesthesiological considerations on tocolytic and uterotonic therapy in obstetrics.

AIM: Significant side effects of tocolytic and uterotonic substances may be of concern to the anaesthesiologist. Recently, new drugs have been introduced having less side effects for both the mother and the neonate. METHODS: A literature search was undertaken mainly focusing on meta-analyses, to review the possible side effects that might affect the course of anaesthesia and to suggest which precautions should be considered to prevent the occurrence of significant interactions with anaesthetic manipulations and drugs. RESULTS: Magnesium sulphate has a proven benefit in lowering systolic blood pressure and preventing the occurrence of eclampsia, but not as a tocolytic. beta-adrenergic agonists are being abandoned due to the availability of tocolytic agents causing less side effects. Calcium channel blockers (CCB) are frequently used but can cause major maternal cardiovascular complications. Nitroglycerin seems to be appreciated as an acute tocolytic rather than a routine substance during pre-term labour. Cyclo-oxygenase-2 inhibitors are still under investigation but their tocolytic benefit is questionable mainly due to foetal side effects. Atosiban is considered the first-choice tocolytic. With respect to oxytocic drugs, oxytocine, prostaglandines and methylergometrine may all cause serious side effects especially when combined. The cardiovascular side effects of prostaglandins and methylergometrine can be life-threatening. Both oxytocin and carbetocin have a rather low risk for maternal complications. CONCLUSION: Atosiban and CCB are at least as effective tocolytic agents as beta-mimetics but have significantly less side effects. Magnesium sulphate can cause neuromuscular blockade, especially when combined with CCB. Concerning oxytocic agents, short-acting oxyctocin and long-acting carbetocin have the least side effects as compared with prostaglandins and methylergometrine.

Latex allergy: a challenge for anaesthetists.

First reported in 1979, anaesthetists now encounter more and more patients with latex allergy. Several risk groups prone to develop this allergy have been identified. A thorough preoperative interview is necessary to detect high-risk patients. For them, the perioperative period is very dangerous because of the many possibilities of contact with latex-containing materials. There is no cure for latex allergy. Absolute avoidance of contact with latex is the only safe way to treat those who belong to a risk group or who are already allergic. The diagnosis of latex allergy must be kept in mind in every case of perioperative anaphylaxis, even if the patient does not belong to a risk group. In the future, desensitization will probably be useful in helping patients with latex allergy.

[Re-expansion pulmonary oedema in a patient after treatment of pneumothorax]. / Re-expansielongoedeem bij een patiënt na behandeling van een pneumothorax.

In a 32-year-old man with left-sided pneumothorax, dyspnoea and tachypnoea with a drop in blood pressure and severe hypoxaemia recurred during drainage. The chest X-ray revealed an alveolar infiltrate in the middle and lower segments of the left lung that was interpreted as re-expansion pulmonary oedema. The patient was respirated and given extra fluids. Extubation was possible after four days. Re-expansion pulmonary oedema is a rare, potentially lethal complication after treatment of a collapsed lung due to a hydro- or pneumothorax. The oedema usually occurs in the re-expanded lung and must be considered when there is a sudden respiratory or haemodynamic deterioration after drainage of X fluid or air. The diagnosis is made by clinical examination and chest X-ray. Predisposing factors are a large hydro- or pneumothorax, long-term collapse, young age and rapid re-expansion. This complication can be prevented by low negative suction pressures and by aspirating a maximum of 1000 to 1500 ml of pleural fluid. The pathophysiology of re-expansion pulmonary oedema is not completely understood and is probably multifactorial. The treatment is merely supportive: oxygen, intravenous fluid substitution and if necessary artificial ventilation. The use of diuretics should be avoided in patients with hypotension.

Anaphylaxis during anaesthesia: diagnosis and treatment.

Anaphylactic and anaphylactoid reactions during anaesthesia are rare, but potentially life-threatening allergic events. The worst manifestations are cardiovascular collapse, bronchospasm and laryngeal oedema. Anaphylactic and anaphylactoid reactions are clinically indistinguishable. The most incriminated agents are neuromuscular blocking drugs and latex. Treatment consists of instant interruption of contact with possible antigens, 100% oxygen, intubation, adrenaline and volume expansion. The incidence of cross-reactivity between neuromuscular blocking drugs is high. Further investigation of a suspected anaphylactic reaction is mandatory to find the responsible drug and to make future anaesthesia safe. Diagnosis is made with intraoperative tests (serum histamine and mast cell tryptase) and postoperative tests (skin tests and RASTs for specific IgE antibodies).

A multicentre trial comparing different concentrations of ropivacaine plus sufentanil with bupivacaine plus sufentanil for patient-controlled epidural analgesia in labour.

BACKGROUND AND OBJECTIVE: To determine the optimal concentration of ropivacaine for bolus-only patient-controlled epidural labour analgesia, three different doses of ropivacaine were evaluated in comparison with bupivacaine in a double-blinded multicentre study. METHODS: Four hundred-and-fifty labouring parturients at term in three different academic institutions were randomized to four groups receiving bupivacaine 0.125% with sufentanil 0.75 microg mL(-1), ropivacaine 0.125% or 0.175% with sufentanil 0.75 microg mL(-1), or ropivacaine 0.2%. After an initial bolus of 10 mL of the study solution, and once visual analogue scores (VAS) were below 30 mm, patient-controlled epidural analgesia was initiated with a bolus of 4 mL, a lockout interval of 15 min and without a background infusion. Variables studied were the quality of analgesia, incidence of side-effects, the degree of motor blockade, and the mode of delivery. RESULTS: Bupivacaine 0.125% and ropivacaine 0.125% with sufentanil proved equally effective in providing labour analgesia without a difference in local anaesthetic consumption (48.6 +/- 23 mg bupivacaine vs. 52.1 +/- 38 mg ropivacaine), motor blockade or mode of delivery. Ropivacaine 0.175% plus sufentanil enhanced the quality of analgesia of the initial loading dose, whereas ropivacaine 0.2% without sufentanil increased the consumption of local anaesthetics (80.2 +/- 34 mg; P < 0.05) and the degree of motor blockade. CONCLUSION: Despite recent studies indicating that bupivacaine and ropivacaine may not be equipotent, both local anaesthetics provided equi-effective analgesia at equal doses without a difference in side-effects.

Intradermal skin testing in the investigation of suspected anaphylactic reactions during anaesthesia--a retrospective survey.

An anaphylactic reaction is a rare, but severe anaesthetic complication. In this retrospective survey we report on patients with a severe suspected anaphylactic reaction during anaesthesia and the investigation with intradermal skin testing of these suspected anaphylactic reactions. In the patients with an anaphylactic reaction to neuromuscular blocking drugs, the subsequent anaesthetic history was examined. Sixty-five patients suffered a suspected anaphylactic reaction between 1976 and 2001. In 47 patients skin testing was performed and 43 of these patients had positive skin tests: neuromuscular blockings drugs and succinylcholine more specifically, were the most frequently incriminated drugs. After the anaphylactic reaction 19 patients had surgery on 26 occasions with the use of a skin-test-negative neuromuscular blocking drug; no problems occurred. Skin testing proved to be a reliable tool to investigate suspected anaphylactic reactions during anaesthesia and to guide the future use of neuromuscular blocking drugs.

Influence of maternal position during epidural labor analgesia.

The influence of maternal position on the spread of local anesthetics in low concentration has not been well examined during epidural analgesia for labor. This study was designed to investigate the differences in sensory block, pain relief and incidence of supine hypotensive syndrome between parturients in the left lateral position and in a modified supine position. Sixty-seven parturients were randomly assigned to lie either in the left lateral position (n = 34) or in a modified supine position (n = 33), and received 0.125% bupivacaine 10 mL with epinephrine 1:800000 and sufentanil 7.5 microg. At 20 min parturients in the modified supine position turned to the left lateral position and a second investigator, unaware of the initial position, measured the extent of the sensory block at 20 and 30 min and just before a second epidural injection was requested. More dermatomes were blocked on the dependent side when the dose was injected in the left lateral position (at 20 and 30 min: P < 0.05; before the second epidural injection: P < 0.0005). In the modified supine position the incidence of bilaterally blocked dermatomes T10-L1 was greater at 20 and 30 min (P < 0.05) and the pain on a visual analogue scale was better at 30 min (P < 0.05). Three parturients in the modified supine position had signs and symptoms of supine hypotensive syndrome. We conclude that injecting in the modified supine position results in a more equal spread of local anesthetic and better pain relief.

Pituitary responsiveness to GH-releasing hormone, GH-releasing peptide-2 and thyrotrophin-releasing hormone in critical illness.

OBJECTIVE: Protein hypercatabolism and preservation of fat depots are hallmarks of critical illness, which is associated with blunted pulsatile GH secretion and low circulating IGF-I, TSH, T4 and T3. Repetitive TRH administration is known to reactivate the pituitary-thyroid axis and to evoke paradoxical GH release in critical illness. We further explored the hypothalamic-pituitary function in critical illness by examining the effects of GH-releasing hormone (GHRH) and/or GH-releasing peptide-2 (GHRP-2) and TRH administration. PATIENTS AND DESIGN: Critically ill adults (n = 40; mean age 55 years) received two i.v. boluses with a 6-hour interval (0900 and 1500 h) within a cross-over design. Patients were randomized to receive consecutively placebo and GHRP-2 (n = 10), GHRH and GHRP-2 (n = 10), GHRP-2 and GHRH+GHRP-2 (n = 10), GHRH+GHRP-2 and GHRH+GHRP-2 + TRH (n = 10). The GHRH and GHRP-2 doses were 1 microgram/kg and the TRH dose was 200 micrograms. Blood samples were obtained before and 20, 40, 60 and 120 minutes after each injection. MEASUREMENTS: Serum concentrations of GH, T4, T3, rT3, thyroid hormone binding globulin (TBG), IGF-I, insulin and cortisol were measured by RIA; PRL and TSH concentrations were determined by IRMA. RESULTS: Critically ill patients presented a striking GH response to GHRP-2 (mean +/- SEM peak GH 51 +/- 9 micrograms/l in older patients and 102 +/- 26 micrograms/l in younger patients; P = 0.005 vs placebo). The mean GH response to GHRP-2 was more than fourfold higher than to GHRH (P = 0.007). In turn, the mean GH response to GHRH+GHRP-2 was 2.5-fold higher than to GHRP-2 alone (P = 0.01), indicating synergism. Adding TRH to the GHRH+GHRP-2 combination slightly blunted this mean response by 18% (P = 0.01). GHRP-2 had no effect on serum TSH concentrations whereas both GHRH and GHRH+GHRP-2 evoked an increase in peak TSH levels of 53 and 32% respectively. The addition of TRH further increased this TSH response > ninefold (P = 0.005), elicited a 60% rise in serum T3 (P = 0.01) and an 18% increase in T4 (P = 0.005) levels, without altering rT3 or TBG levels. GHRH and/or GHRP-2 induced a small increase in serum PRL levels. The addition of TRH magnified the PRL response 2.4-fold (P = 0.007). GHRP-2 increased basal serum cortisol levels (531 +/- 29 nmol/l) by 35% (P = 0.02); GHRH provoked no additional response, but adding TRH further increased the cortisol response by 20% (P = 0.05). CONCLUSIONS: The specific character of hypothalamic-pituitary function in critical illness is herewith extended to the responsiveness to GHRH and/or GHRP-2 and TRH. The observation of striking bursts of GH secretion elicited by GHRP-2 and particularly by GHRH+GHRP-2 in patients with low spontaneous GH peaks opens the possibility of therapeutic perspectives for GH secretagogues in critical care medicine.