Subcostal TAP block: one or two sequential injections? A cadaveric study.

BACKGROUND AND OBJECTIVES: The subcostal transversus abdominis plane block (scTAPB) provides analgesia to the anterior abdominal wall but analgesic spread following a single injection remains modest and variable. The oblique scTAPB, which is performed with a continuous injection during needle progression into the TAP along the oblique subcostal line, may extend the block to the whole anterior abdominal wall but needle progression by hydrodissection may be difficult, explaining why this block is not widely used. This study investigated if two sequential scTAPB injections (2scTAPI) may reach more nerves than a single scTAPB (1scTAPI). METHODS: After institutional approval and under ultrasound guidance, a single injection of 20 mL of blue dye was performed in 16 cadaveric subjects into the TAP along the costal margin and lateral to the semilunaris line (1scTAPI). On the opposite side, a 20 mL of green solution was split into two injections (2scTAPI), using one injection medial and one lateral to the semilunaris line. Dye spread was assessed via gross anatomical dissection using an indirect method to quantify the involvement of the anterior cutaneous branches of the intercostal nerves with each technique. A nerve was considered stained if the dye was observed in the TAP, reaching the costal margin aligned with the bony extremity of its corresponding rib. RESULTS: According to the spread to the costal margin, the estimated median number of consecutive nerves reached by dye after 2scTAPI was 5 (IQR 5-6) vs 3 (IQR 3-4) for 1scTAPI (p=0.00001). Spread after 2scTAPI suggested coverage of nerves originating from T8 to T12 in 85% of the subjects, and from T7 to T12 in 5 out of 17 cases. Spread following the 1scTAPI suggested coverage of nerves from T9 to T11 in most cases. CONCLUSIONS: In a cadaveric model, a larger spread at the costal margin was obtained after 2scTAPI, suggesting a greater coverage of anterior branches of abdominal wall nerves compared with 1scTAPI. Clinical studies are needed to confirm these results.

Early brain metabolic disturbances associated with delayed cerebral ischemia in patients with severe subarachnoid hemorrhage.

Delayed cerebral ischemia (DCI) is a devastating complication of aneurysmal subarachnoid hemorrhage (ASAH) causing brain infarction and disability. Cerebral microdialysis (CMD) monitoring is a focal technique that may detect DCI-related neurochemical changes as an advance warning. We conducted retrospective analyses from 44 poor-grade ASAH patients and analyzed glucose, lactate, pyruvate, and glutamate concentrations in control patients without DCI (n = 19), and in patients with DCI whose CMD probe was located within (n = 17) or outside (n = 8) a new infarct. When monitored from within a lesion, DCI was preceded by a decrease in glucose and a surge in glutamate, accompanied by increases in lactate/pyruvate and lactate/glucose ratios whereas these parameters remained stable in control patients. When CMD monitoring was performed outside the lesion, the glutamate surge was absent, but glucose and L/G ratio were still significantly altered. Overall, glucose and L/G ratio were significant biomarkers of DCI (se96.0, spe73.7-68.4). Glucose and L/G predicted DCI 67 h before CT detection of a new infarct. The pathogenesis of DCI therefore induces early metabolic disturbances that can be detected by CMD as an advance warning. Glucose and L/G could provide a trigger for initiating further examination or therapy, earlier than when guided by other monitoring techniques.

Accuracy of bedside bidimensional transcranial ultrasound versus tomodensitometric measurement of the third ventricle.

BACKGROUND AND PURPOSE: To evaluate the accuracy of transcranial duplex sonography (TCS) for measuring the diameter of the third ventricle (DTV) and the brain midline shift (MLS), as compared to cerebral CT. METHODS: Single-center retrospective study including 177 patients admitted to the neurological intensive care unit (NICU). We studied the correlation between TCS and CT measurements of DTV and MLS using a Bland-Altman analysis. The best threshold of DTV to diagnose acute hydrocephalus was evaluated with a receiver operating characteristic (ROC) analysis. RESULTS: We analyzed 177 pairs of CT-TCS measurements for DTV and 165 for MLS. The mean time interval between CT and TCS was 87 ± 73 minutes. Median DTV measurement on CT was 4 ± 3 mm, and 5 ± 3 mm by TCS. Median MLS on CT was 2 ± 3 mm, and 2 ± 4 mm by TCS. The Pearson correlation coefficient (r2 ) was .96 between TCS and CT measurements (p < .001). The Bland-Altman analysis found a proportional bias of 0.69 mm for the DTV with a limit of agreement ranging between -3.04 and 2.53 mm. For the MLS, the proportional bias was 0.23 mm with limits of agreements between -3.5 and 3.95. The area under the ROC curve was .97 for the detection of hydrocephalus by DTV on TCS, with a best threshold of 5.72 mm (Sensitivity [Se] = 92% Specificity [Sp] = 92.1%). CONCLUSIONS: TCS seems to be a reliable and accurate bedside technique for measuring both DTV and MLS, which might allow detection of acute hydrocephalus among NICU patients.

Placing intracerebral probes to optimise detection of delayed cerebral ischemia and allow for the prediction of patient outcome in aneurysmal subarachnoid haemorrhage.

Cerebral microdialysis could be useful to detect delayed cerebral ischemia in aneurysmal subarachnoid haemorrhage patients. The optimal location of the probes, however, remains controversial. Here, we determined the vascular territories with the highest infarct risk in relation to aneurysm location to define probe implantation guidelines. These guidelines were retrospectively validated by studying the likelihood of probe to fall in a secondary infarct area, and by analysing their influence to predict patient outcome. The vascular territories with highest risk of infarction were the anterior cerebral arteries for anterior communicating artery aneurysms and the ipsilateral middle cerebral artery for internal carotid artery, posterior communicating artery and middle cerebral artery aneurysms. When cerebral microdialysis probes had been implanted in these territories, 79% were located within an infarcted area versus 54% when they were implanted in other territories. Delayed cerebral ischemia was detected only when the probe was located within a brain area later affected by secondary infarction, which could justify the use of implantation guidelines. Moreover, individual patient outcomes could be predicted when probes were placed in the brain territories as suggested by this study. Thus, a precise probe placement algorithm can improve delayed cerebral ischemia detection sensitivity and allow for a better prediction concerning patient outcome.

Anxiety and stress among anaesthesiology and critical care residents during high-fidelity simulation sessions.

OBJECTIVES: High-fidelity simulation (HFS) calls heavily upon cognitive capacities and generates stress and anxiety. The objectives of this prospective, observational study were to assess trait anxiety and fear of negative evaluation (FNE) in anaesthesiology and critical care residents and appraise their state anxiety levels and cardiovascular responses during HFS training sessions. SUBJECTS AND METHODS: First-year anaesthesiology and critical care residents completed the French-Canadian adaptation of the State-Trait Anxiety Inventory (IASTA Y-1: state anxiety, IASTA Y-2: trait anxiety) and the French adaptation of the Fear of Negative Evaluation Scale (FNE). Their heart rate (HR) and blood pressure (BP) were assessed before and after the training session. RESULTS: Twenty-three residents (8 women, 15 men) were included in the study. IASTA Y-1 and Y-2 scores were low (respectively 40.2±9.9 and 39.7±8) and FNE scores were moderate (16.7±5.5). HR measurements before and after the training sessions were significantly higher than at rest (respectively 78±19, 80±17 and 63±9b/min; P<0.001). BP measurements before and after the HFS sessions were not significantly different. The IASTA Y-2 and FNE scores of female residents were significantly higher than those of male residents (respectively P=0.004 and P=0.049). CONCLUSION: First-year anaesthesiology and critical care residents had low trait anxiety and FNE. HFS training increased their HR but not their BP. Their state anxiety also remained low. Several differences between individuals were noted, particularly between men and women.

Hyperchloremic metabolic acidosis following plasma exchange during myasthenia gravis crisis.

BACKGROUND: Therapeutic plasma exchanges are increasingly used, notably during myasthenia gravis crisis. Repeated exchanges may induce severe adverse events. CASE: We reported a case of symptomatic hyperchloremic metabolic acidosis following a therapeutic plasma exchange. Analysis of 4% albumin substitution solution revealed a chloride concentration of 145 mmol/L, which could explain this acidosis. DISCUSSION: Infusion of high volume of 4% albumin during plasma exchanges may produce hyerchloremic metabolic acidosis. CONCLUSION: Special attention should be paid when repeated plasma exchanges are performed. J. Clin. Apheresis 31:479-480, 2016. © 2015 Wiley Periodicals, Inc.

Opioid consumption after levobupivacaine scalp nerve block for craniosynostosis surgery.

BACKGROUND AND OBJECTIVES: Craniosynostosis surgery is considered a very painful procedure due to extended scalp and periosteal detachment, and is associated with prolonged postoperative consumption of opioids and their side effects. In this observational descriptive case series study, we investigated perioperative opioid consumption in children undergoing craniosynostosis repair under general anesthesia when scalp nerve block with levobupivacaine was involved. METHODS: After standard anesthesia induction, scalp nerve block with levobupivacaine 2 mg/kg plus epinephrine 1:800,000 was performed. Hemodynamic parameters and opioid consumption were noted. Patients were monitored in the recovery room. Requirements of additional analgesia, indicated by the Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) pain score of >9, and incidence of side effects (sedation, nausea, and vomiting) were recorded during the first 24 hours. RESULTS: A total of 32 patients were recruited in this study; 88% of them needed morphine rescue in the recovery room because they had high CHEOPS scores. Trigonocephaly was the most frequent type of craniosynostosis (37.5%), requiring 50% more opioids in the postoperative period than other forms of craniosynostosis. CONCLUSION: Scalp nerve block can be proposed as a complement to the routine craniosynostosis anesthetic protocol, because it is easy to perform, seems to reduce the need for supplementary opioids during the perioperative period, and can reduce the risk of developing acute opioid tolerance and chronic pain. In the event of trigonocephaly or craniofacial reconstruction, a complementary infraorbital nerve block can be added.

Outcome of poor-grade subarachnoid hemorrhage as determined by biomarkers of glucose cerebral metabolism.

PURPOSE: The aim of this study was to determine if the measurement of blood biomarkers of glucose cerebral metabolism, performed with retrograde jugular catheter, could predict the outcome of poor-grade aneurysmal subarachnoid hemorrhage (aSAH) patients. METHODS: This study was conducted in 68 poor-grade aSAH patients. A total of 4,024 blood samples obtained from jugular and radial catheters were analyzed for glucose, lactate, and oxygen content every 8 h for 10 ± 0.5 days. Metabolic ratio (MR) and lactate-oxygen index (LOI) were obtained by ratios using arterio-jugular differences. Functional outcome was evaluated at 12 months with the Glasgow Outcome Scale. RESULTS: Outcome was unfavorable in 40 patients. In this group of patients, the MR was significantly lower (p < 0.0001) and the LOI was significantly higher (p = 0.0001) than in the group with favorable outcome. The MR cutoff value, below which the patients are likely to have an unfavorable outcome, was determined to be 3.35. More interestingly, the data obtained in this study demonstrated that the patients achieving an unfavorable outcome were distinguished from those with a favorable outcome by having at least three events of MR inferior to 3.35 (sensitivity = 90 %, specificity = 82.1 %). Moreover, in patients who developed cerebral vasospasm, we observed a significant decrease in the MR. CONCLUSION: Our data provide additional support to the view that the MR is a reliable marker for predicting the outcome of poor-grade aSAH patients. Prospective studies are needed to confirm its value in multimodal monitoring.

Assessment of jugular blood oxygen and lactate indices for detection of cerebral ischemia and prognosis.

Levels of jugular blood oxygen saturation (SjvO2) and lactate have been proposed as indicators of cerebral ischemia and prognosis. However, sensitivity and specificity of these markers remain unknown. We retrospectively analyzed records of a series of 43 comatose patients at risk for cerebral ischemia, mainly after head injuries or subarachnoidal hemorrhage. Their SjvO2, jugulo-arterial lactate difference (VADLactate), and lactate-oxygen index (LOI) were determined every 8 hours. An increase in VADLactate and LOI was found, indicative of ischemia on CT scan, with threshold values of 0.30 mmol/L and 0.15, respectively. Sensitivity and specificity were 100% and 64%, respectively, for the VADLactate threshold, and 90% and 55%, respectively, for the LOI threshold. Regarding prediction of a poor outcome, only an increase in VADLactate had a predictive value with a sensitivity of 100% and specificity of 67%. No threshold value with sufficient sensitivity and specificity was found for SjvO2, as indicator of either ischemia or outcome. During progression to brain death, VADLactate and LOI reached abnormal levels earlier than cerebral perfusion pressure or SjvO2. They reacted markedly to focal ischemia due to vasospasm. Hyperlactacidemia rendered VADLactate and LOI uninterpretable by causing a brain lactate influx. Present data, if confirmed by a prospective study, would justify inclusion of intermittent VADLactate and LOI determinations in the multimodal cerebral monitoring.