Early Autocalibrated Arterial Waveform Analysis for the Management of Burn Shock-A Cohort Study.

Adequate fluid therapy is crucial for resuscitation after major burns. To adapt this to individual patient demands, standard is adjustment of volume to laboratory parameters and values of enhanced hemodynamic monitoring. To implement calibrated parameters, patients must have reached the intensive care unit (ICU). The aim of this study was, to evaluate the use of an auto-calibrated enhanced hemodynamic monitoring device to improve fluid management before admission to ICU. We used PulsioflexProAqt® (Getinge) during initial treatment and burn shock resuscitation. Analysis was performed regarding time of measurement, volume management, organ dysfunction, and mortality. We conducted a monocentre, prospective cohort study of 20 severely burned patients, >20% total body surface area (TBSA), receiving monitoring immediately after admission. We compared to 57 patients, matched in terms of TBSA, age, sex, and existence of inhalation injury out of a retrospective control group, who received standard care. Hemodynamic measurement with autocalibrated monitoring started significantly earlier: 3.75(2.67-6.0) hours (h) after trauma in the study group versus 13.6(8.1-17.5) h in the control group (P < .001). Study group received less fluid after 6 h: 1.7(1.2-2.2) versus 2.3(1.6-2.8) ml/TBSA%/kg, P = .043 and 12 h: 3.0(2.5-4.0) versus 4.2(3.1-5.0) ml/TBSA%/kg, P = .047. Dosage of norepinephrine was higher after 18 h in the study group: 0.20(0.12-0.3) versus 0.08(0.02-0.18) µg/kg/min, P = .014. The study group showed no adult respiratory distress syndrome versus 21% in the control group, P = .031. There was no difference in other organ failures, organ replacement therapy, and mortality. The use of auto-calibrated enhanced hemodynamic monitoring is a fast and feasible way to guide early fluid therapy after burn trauma. It reduces the time to reach information about patient's volume capacity. Management of fluid application changed to a more restrictive fluid use in the early period of burn shock and led to a reduction of pulmonary complications.

Vascular Endothelial Growth Factor as Potential Biomarker for COVID-19 Severity.

INTRODUCTION: COVID-19 is characterized by immunological responses to viral replication and coherent with endothelitis, microvascular disturbance of lung vasculature and coagulopathy. Vascular Endothelial Growth Factor (VEGF) is a proangiogenic mediator regulating endothelial changes. It is induced by proinflammatory signaling and hypoxia. We sought to determine whether VEGF levels differ between SARS-CoV-2-positive patients of different disease severity and whether VEGF might be useful in risk stratification. METHODS: After retrospective screening of all SARS-CoV-2-positive patients treated in Unfallkrankenhaus Berlin in 2020, we included those with documented VEGF measurement. We extracted laboratory values and clinical parameters. An exploratory data analysis was performed to detect possible relations between VEGF level and clinical disease features. RESULTS: We included 167 SARS-CoV-2-positive patients of which 139 suffered from COVID-19. Seventy-one of the COVID-19 patients had to be treated in the intensive care unit (ICU), those patients exhibited higher VEGF levels than those being admitted to normal wards (535 vs 279 pg/L, P < .001). APACHE-2 (Acute Physiology And Chronic Health Evaluation Score) correlated with mortality and patients with high values showed higher VEGF concentrations on admission (456 vs 875 pg/L, p = 0.006). Receiver operating characteristic analytic revealed that the occurrence of organ dysfunctions like acute respiratory distress syndrome (ARDS), shock, or acute kidney injury could be predicted by VEGF. It was significantly higher in patients who later died compared to survivors (637 vs 389 pg/mL, P = 0.041) and predicted mortality with same accuracy as established markers. In our cohort, association of VEGF above 277 pg/L on admission with risk of ARDS could be confirmed in logistic regression adjusting for possible confounding factors (odds ratio 3.1, 95% confidence interval: 1.34-7.7). DISCUSSION: Even though there are several limitations to this retrospective study it revealed that in COVID-19 patients VEGF can contribute to the prediction of necessity of ICU, mortality and the prediction of ARDS, kidney injury or shock. Its use in risk stratification and potential pathogenetic involvement should be further investigated.

Hepatobiliary long-term consequences of COVID-19: dramatically increased rate of secondary sclerosing cholangitis in critically ill COVID-19 patients.

BACKGROUND: Increasing evidence suggests that secondary sclerosing cholangitis (SSC), which can lead to cirrhosis or liver failure, may be a hepatobiliary long-term complication of COVID-19. The aim of this study was to estimate the frequency and outcome of this COVID-19 sequela and to identify possible risk factors. METHODS: This observational study, conducted at University Hospital Charité Berlin and Unfallkrankenhaus Berlin, Germany, involved hospitalized patients with COVID-19 pneumonia, including 1082 ventilated COVID-19 patients. We compared COVID-19 patients who developed SSC with a COVID-19 control group by univariate and multivariate analyses. RESULTS: SSC occurrence after COVID-19 was observed exclusively in critically ill patients with invasive ventilation, albeit with extreme clustering among them. One in every 43 invasively ventilated COVID-19 patients developed this complication. Risk factors preceding the development of secondary sclerosing cholangitis in critically ill COVID-19 patients (SSC-CIP) were signs of systemic reduced blood oxygen supply (e.g., low PaO2/FiO2, ischemic organ infarctions), multi-organ failure (high SOFA score) at admission, high fibrinogen levels and intravenous ketamine use. Multivariate analysis confirmed fibrinogen and increased plasma lactate dehydrogenase as independent risk factors associated with cholangiopathy onset. The 1-year transplant-free survival rate of COVID-19-associated SSC-CIP was 40%. CONCLUSIONS: COVID-19 causes SSC-CIP in a substantial proportion of critically ill patients. SSC-CIP most likely develops due to severe tissue hypoxia and fibrinogen-associated circulatory disturbances. A significant increase of patients with SSC-CIP is to be expected in the post-COVID era.

Intra- and Extrathoracic Malignant Tracheoesophageal Fistula-A Differentiated Reconstructive Algorithm.

BACKGROUND: Tracheoesophageal fistulae (TEF) after oncologic resections and multimodal treatment are life-threatening and surgically challenging. Radiation and prior procedures hamper wound healing and lead to high complication rates. We present an interdisciplinary algorithm for the treatment of TEF derived from the therapy of consecutive patients. PATIENTS AND METHODS: 18 patients (3 females, 15 males) treated for TEF from January 2015 to July 2017 were included. Two patients were treated palliatively, whereas reconstructions were attempted in 16 cases undergoing 24 procedures. Discontinuity resection and secondary gastric pull-up were performed in two patients. Pedicled reconstructions were pectoralis major (n = 2), sternocleidomastoid muscle (n = 2), latissimus dorsi (n = 1) or intercostal muscle (ICM, n = 7) flaps. Free flaps were anterolateral thigh (ALT, n = 4), combined anterolateral thigh/anteromedial thigh (ALT/AMT, n = 1), jejunum (n = 3) or combined ALT-jejunum flaps (n = 2). RESULTS: Regarding all 18 patients, 11 of 16 reconstructive attempts were primarily successful (61%), whereas long-term success after multiple procedures was possible in 83% (n = 15). The 30-day survival was 89%. Derived from the experience, patients were divided into three subgroups (extrathoracic, cervicothoracic, intrathroracic TEF) and a treatment algorithm was developed. Primary reconstructions for extra- and cervicothoracic TEF were pedicled flaps, whereas free flaps were used in recurrent or persistent cases. Pedicled ICM flaps were mostly used for intrathoracic TEF. CONCLUSION: TEF after multimodal tumor treatment require concerted interdisciplinary efforts for successful reconstruction. We describe a differentiated reconstructive approach including multiple reconstructive techniques from pedicled to chimeric ALT/jejunum flaps. Hereby, successful reconstructions are mostly possible. However, disease and patient-specific morbidity has to be anticipated and requires further interdisciplinary management.

Using chloroprocaine for spinal anaesthesia in outpatient knee-arthroscopy results in earlier discharge and improved operating room efficiency compared to mepivacaine and prilocaine.

PURPOSE: Knee arthroscopies are regularly carried out in an outpatient setting. The purpose of this retrospective analysis was to investigate the impact of different local anaesthetics for spinal anaesthesia on operating room efficiency (perioperative process times) and postoperative recovery. This study aims to determine the optimal LA for SPA in patients undergoing knee arthroscopy at a day-surgery centre. METHODS: Anaesthesia records of all patients undergoing knee arthroscopy under spinal anaesthesia from 2010 until 2017 were analysed. Patients were categorised as having received spinal anaesthesia with prilocaine, mepivacaine or chloroprocaine. RESULTS: Three-hundred and nine patients were included. Postoperative recovery was significantly faster for chloroprocaine 1% compared with both other local anaesthetics regarding all stages of recovery until discharge. Perioperative processes and surgery time were significantly shorter when chloroprocaine was used. Early postoperative pain occurred more frequently and earlier after spinal anaesthesia with chloroprocaine. Nevertheless, pain intensity did not differ between groups. CONCLUSION: Spinal anaesthesia provides reliable blocks for outpatient knee arthroscopy. Considerations on the choice of local anaesthetic for spinal anaesthesia must include not only the recovery profile, but also the impact on operating room efficiency. Due to a superior recovery profile, low incidences of adverse side effects and raised operating room efficiency, chloroprocaine is the recommendable local anaesthetic for spinal anaesthesia in patients undergoing knee arthroscopy in an ambulatory setting. Since the frequency of SPA in patients undergoing outpatient knee arthroscopy is rising yearly, the results of this study are of high clinical relevance. The use of chloroprocaine leads to improved recovery, optimized perioperative processes and consecutively to a raised OR efficiency. LEVEL OF EVIDENCE: III.

Influence of anxiolytic premedication on vasovagal reactions and home readiness following outpatient intrathecal anaesthesia-A retrospective analysis.

BACKGROUND: Vasovagal reactions during application of intrathecal anaesthesia (IA) are associated with high anxiety levels. A high percentage of patients undergoing outpatient surgery suffer from anxiety. Anxiolytic premedication in day-surgery is suspected to delay recovery and discharge and is, therefore, not routinely used. The aim of this retrospective analysis was to detect the influence of anxiolytic premedication on the incidence of vasovagal reactions and time until discharge home. METHODS: Anaesthesia records of all patients undergoing outpatient surgery under low-dose IA from January 2008 to June 2017 were analysed. Incidences of vasovagal reactions with a decrease in blood pressure and/or heart rate and need for cardiovascular activating medications were documented. Patients were categorised as having received an anxiolytic premedication or not. The time from intrathecal injection of the local anaesthetic until readiness for discharge was recorded. RESULTS: The records of 2747 patients were analysed. One thousand two hundred and ninety-one of them received an anxiolytic premedication of 1-2 mg midazolam intravenously. Three hundred and fourteen patients had vasovagal incidents during application of IA (no premedication n = 217 [15.0%], premedication n = 97 [7.5%], P < 0.0001). Premedication did not prolong time to achieve readiness for discharge (mepivacaine: P = 0.5886, chloroprocaine: P = 0.1555). However, in the prilocaine group, premedication led to a significantly earlier achievement of readiness for discharge (P = 0.0002). CONCLUSION: Anxiolytic premedication significantly reduces the incidence of vasovagal reactions during the application of IA and does not affect time until readiness for discharge.

Retrospective analysis of mepivacaine, prilocaine and chloroprocaine for low-dose spinal anaesthesia in outpatient perianal procedures.

PURPOSE: Perianal procedures are carried out in an outpatient setting regularly. The purpose of this retrospective analysis was to investigate the impact of different local anaesthetics (LA) for spinal anaesthesia (SPA) on operating room (OR) efficiency (perioperative process times, turnaround times) and postoperative recovery. This study aims on the determination of the optimal LA for low-dose SPA in the specific setting of a high-volume day-surgery centre. METHODS: Anaesthesia records of all patients undergoing perianal outpatient surgery under saddle-block SPA at the Mannheim University Medical Centre from 2008 until 2017 were analysed. Patients were categorized as having received prilocaine, mepivacaine or chloroprocaine. RESULTS: Two thousand seven hundred forty-six patients were included. Postoperative recovery was faster for chloroprocaine 1% compared with both other LAs. Preoperative processes but not process times in the OR were shorter for chloroprocaine. In contrary, turnaround times were significantly prolonged when chloroprocaine had been used, leading to reduction of OR efficiency. CONCLUSION: Low-dose SPA provides reliable blocks for perianal surgery. Considerations on the choice of LA for SPA must include not only the recovery profile, but also the impact on OR efficiency. Due to shorter turnaround times and a manageable prolonged duration of stay, prilocaine is the preferable LA for low-dose SPA in perianal outpatient surgery at a high-volume day-surgery centre.

Spinal anaesthesia with chloroprocaine 1% versus total intravenous anaesthesia for outpatient knee arthroscopy: A randomised controlled trial.

BACKGROUND: Both general and spinal anaesthesia with short-acting local anaesthetics are suitable and reliable for knee arthroscopy as an ambulatory procedure. Chloroprocaine (CP) 1% seems to be the ideal spinal local anaesthetic for this indication. OBJECTIVE: The aim of this study was to compare spinal anaesthesia using CP 1% with general for outpatient knee arthroscopy with regard to procedure times, occurrence of pain, patient satisfaction and recovery, and also costs. DESIGN: A randomised controlled single-centre trial. SETTING: University Medical Centre Mannheim, Department of Anaesthesiology and Surgical Intensive Care Medicine, Mannheim, Germany. April 2014 to August 2015. PATIENTS: A total of 50 patients (women/men, 18 to 80 years old, ASA I to III) undergoing outpatient knee arthroscopy were included. A contra-indication to an allocated anaesthetic technique or an allergy to medication required in the protocol led to exclusion. INTERVENTIONS: Either general anaesthesia with sufentanil, propofol and a laryngeal mask for airway-management or spinal with 40-mg CP 1% were used. We noted procedure times, patient satisfaction/recovery and conducted a 7-day follow-up. MAIN OUTOMES: Primary outcome was duration of stay in the day-surgery centre. Secondary outcomes were first occurrence of pain, patient satisfaction, quality of recovery and adverse effects. In addition, we analysed treatment costs. RESULTS: Spinal had faster recovery than general anaesthesia with patients reaching discharge criteria significantly earlier [117 min (66 to 167) versus 142 min (82 to 228), P = 0.0047]. Pain occurred significantly earlier in the general anaesthesia group (P = 0.0072). Costs were less with spinal anaesthesia (cost ratio spinal: general 0.57). Patients felt significantly more uncomfortable after general anaesthesia (P = 0.0096). CONCLUSION: Spinal anaesthesia with 40-mg CP 1% leads to a significantly earlier discharge and is cheaper compared with general. TRIAL REGISTRATION: German Clinical Trials Register, www.drks.de, identifier: DRKS00005989.

[New short-acting local anaesthetics for spinal anaesthesia - Well-tried substances for ambulatory surgery]. / Neue kurzwirksame Lokalanästhetika in der Spinalanästhesie - Altbewährte Substanzen für ambulante Eingriffe.

More and more operative procedures are performed in an ambulatory setting. Many patients are denied spinal anaesthesia, although it provides several advantages. Innovative pharmaceutical formulations of well-tried local anaesthetics have created "new" substances that are ideal for ambulatory surgery due to their fast onset, short duration of action, and very low incidence of complications such as transient neurological symptoms (TNS). Both hyperbaric prilocaine 2% and preservative-free chloroprocaine 1% were recently approved for spinal application in Germany. Additional perioperative measures, such as the use of atraumatic, thin spinal needles (25 or 27G), restrictive volume management, and early patient mobilisation, lead to a further reduction of complications. The new S1 guideline of the German Society of Anaesthesiology and Intensive Care Medicine encourages us anaesthetists to use spinal anaesthesia more frequently in an ambulatory setting.

Interscalene plexus block versus general anaesthesia for shoulder surgery: a randomized controlled study.

OBJECTIVES: This randomized clinical trial evaluates interscalene brachial plexus block (ISB), general anaesthesia (GA) and the combination of both anaesthetic methods (GA + ISB) in patients undergoing shoulder arthroscopy. METHODS: From July 2011 until May 2012, 120 patients (male/female), aged 20-80 years, were allocated randomly to receive ISB (10 ml mepivacaine 1 % and 20 ml ropivacaine 0.375%), GA (propofol, sunfentanil, desflurane) or ISB + GA. The primary outcome variable was opioid consumption at the day of surgery. Anaesthesia times were analysed as secondary endpoints. RESULTS: After surgery, 27 of 40 patients with a single ISB bypassed the recovery room (p < 0.0001). Postoperative monitoring time was significantly shorter with single ISB compared with both other groups [GA: 93 (5-182) min vs. GA + ISB: 57.5 (11-220) min vs. ISB: 35 (5-106) min, p < 0.0001]. Opioid consumption was reduced using a single ISB at the day of surgery [GA: n = 25 vs. GA + ISB: n = 10 vs. ISB: n = 10, p = 0.0037]. CONCLUSION: ISB is superior to GA and GA + ISB in patients undergoing shoulder arthroscopy in terms of faster recovery and analgesics consumption.

Randomised clinical trial of pilonidal sinus operations performed in the prone position under spinal anaesthesia with hyperbaric bupivacaine 0.5 % versus total intravenous anaesthesia.

PURPOSE: The aim of this randomised clinical trial was to determine whether spinal anaesthesia (SPA) is superior to total intravenous anaesthesia (TIVA) in patients undergoing pilonidal sinus (PS) operations in the prone position. METHODS: After approval of the local ethics committee, suitable patients aged 19-49 years were randomised to SPA (7.5 mg hyperbaric bupivacaine) or TIVA (Propofol and Fentanyl). Cumulative consumption of analgesics, postoperative recovery, complications and patient satisfaction were evaluated. RESULTS: A total of 50 patients were randomised within a 24-month period. Median monitoring time in the recovery room was 0 (0-11) min for SPA versus 40 (5-145) min for TIVA (p < 0.0001). Patients in the SPA group were able to drink (40.5 (0-327) min versus TIVA 171 (72-280) min, p < 0.0001) and eat (55 (0-333) min versus TIVA 220 (85-358), p < 0.0001) earlier. More patients with a TIVA needed analgesics in the recovery room (SPA n = 0 versus TIVA n = 6, p = 0.0023) and suffered more frequently from a sore throat (SPA n = 0 versus TIVA n = 11, p = 0.0001). Two patients with a TIVA suffered from nausea and vomiting. Patients of both groups were equally satisfied with the anaesthesia technique offered. CONCLUSIONS: SPA with 7.5 mg hyperbaric bupivacaine is superior to TIVA in patients undergoing PS operations in the prone position in terms of analgesia consumption in the recovery room, recovery times and postoperative complications.

Influence of the pre-operative time in upright sitting position and the needle type on the incidence of post-dural puncture headache (PDPH) in patients receiving a spinal saddle block for anorectal surgery.

BACKGROUND: A spinal saddle block can be a safe method for anorectal surgery with a low rate of complications when performed with the right technique. A dreaded complication is the post-dural puncture headache (PDPH), which can be decreased by the use of non-cutting spinal needles. Regrettably, cutting Quincke (Q)-type needles are still widely used for economic reasons. Besides size and design of a spinal needle, the pre-operative time in upright sitting position may also influence the incidence of PDPH after spinal saddle block. METHODS: Within 4 months, 363 patients undergoing anorectal surgery in saddle block technique were randomised to receive either a 27-gauge (G) pencil-point (PP) or a 27-G Q spinal needle and were pre-operatively left in upright sitting position for 10 or 30 min, respectively. The incidence of PDPH was assessed 1 week after the operation via a telephone interview. RESULTS: Three hundred sixty three patients (219 males/144 females) were analysed. Fifteen patients (4.1%) developed PDPH. Patients receiving spinal anaesthesia with a Q needle suffered significantly more frequently from PDPH [Q: n = 12 (6.6%) vs. PP: n = 3 (1.7%), p = 0.02], but there was no association between PDPH and pre-operative time in the upright position (p = 0.20). CONCLUSIONS: These data prove that using 27-G PP needles is the method with the fewest side effects caused by spinal saddle block, and suggest that the time spent sitting in the upright position is not clinically relevant.

Ventilation-perfusion ratio in perflubron during partial liquid ventilation.

BACKGROUND: Functional magnetic resonance imaging (fMRI) of fluorine-19 allows for the mapping of oxygen partial pressure within perfluorocarbons in the alveolar space (Pao(2)). Theoretically, fMRI-detected Pao(2) can be combined with the Fick principle approach, i.e., a mass balance of oxygen uptake by ventilation and delivery by perfusion, to quantify the ventilation-perfusion ratio (Va/Q) of a lung region: The mixed venous blood and the inspiratory oxygen fraction, which are equal for all lung regions, are measured. In addition, the local expiratory oxygen fraction and the end capillary oxygen content, both of which may differ between the lung regions, are calculated using the fMRI-detected Pao(2). We investigated this approach by numerical simulations and applied it to quantify local Va/Q in the perfluorocarbons during partial liquid ventilation. METHODS: Numerical simulations were performed to analyze the sensitivity of the Va/Q calculation and to compare this approach with another one proposed by Rizi et al. in 2004 (Magn Reson Med 2004;52:65-72). Experimentally, the method was used during partial liquid ventilation in 7 anesthetized pigs. The Pao(2) distribution in intraalveolar perflubron was measured by fluorine-19 MRI. Respiratory gas fractions together with arterial and mixed venous blood samples were taken to quantify oxygen partial pressure and content. Using the Fick principle, the local Va/Q was estimated. The impact of gravity (nondependent versus dependent) of perflubron dose (10 vs 20 mL/kg body weight) and of inspired oxygen fraction (Fio(2)) (0.4-1.0) on Va/Q was examined. RESULTS: In numerical simulations, the Fick principle proved to be appropriate over the Va/Q range from 0.02 to 2.5. Va/Q values were in acceptable agreement with the method published by Rizi et al. In the experimental setting, low mean Va/Q values were found in perflubron (confidence interval [CI] 0.08-0.29 with 20 mL/kg perflubron). At this dose, Va/Q in the nondependent lung was higher (CI 0.18-0.39) than in the dependent lung regions (CI 0.06-0.16; P = 0.006; Student t test). Differences depending on Fio(2) or perflubron dose were, however, small. CONCLUSION: The results show that derivation of Va/Q from local Po(2) measurements using fMRI in perflubron is feasible. The low detected Va/Q suggests that oxygen transport into the perflubron-filled alveolar space is significantly restrained.

High incidence of post-dural puncture headache in patients with spinal saddle block induced with Quincke needles for anorectal surgery: a randomised clinical trial.

PURPOSE: Spinal saddle block represents nearly the ideal anaesthesia technique for anorectal surgery. Post-dural puncture headache (PDPH) is a dreaded complication but can be decreased by the use of non-cutting spinal needles to rates less than 1%. Though, cutting Quincke type needles are still widely used for economic reasons, leading to a higher rate of PDPH. We performed this study to demonstrate a reduction of PDPH by the use of very small 29-G compared with commonly used 25-G Quincke type spinal needles. METHODS: Two hundred sixteen adult patients (male/female, 19-83 years, ASA status I-III) were randomised 1:1 to groups, in which either a 25-G or a 29-G Quincke type spinal needle was used for a spinal saddle block. The incidence of PDPH was assessed during 1 week after surgery. RESULTS: Thirty-nine of 216 patients developed PDPH but there was no difference between the two needle sizes (25-G, n = 18/106 vs. 29-G, n = 21/110, p = 0.6870). Women suffered significantly more from PDPH than men (23/86 vs. 16/130, p = 0.0069). Ambulatory patients had a later onset of PDPH than in-patients (24 h [0.5-72] vs. 2 h [0.2-96], p = 0.0002) and the headache was more severe in these patients (NRS 7 [2-10] vs. NRS 3 [1-8], p = 0.0009). CONCLUSIONS: The use of 29-G compared with 25-G Quincke needles led to no reduction of PDPH and is considerably higher compared with data from pencil-point needles. The use of non-cutting or pencil-point spinal needles should become the standard for performing spinal saddle block.

Influence of sedation on patients' perceptions and recovery in patients undergoing minor perianal procedures under spinal saddle block.

OBJECTIVES: Additional intra-operative sedation may help improve acceptability and comfort of anaesthesia in patients undergoing minor anorectal (perianal) procedures under spinal saddle block. This observational study was done to determine which patients request sedatives and to what extent sedatives affect the patients' recovery. SUBJECTS AND METHODS: During a 6-month period, 500 patients undergoing minor perianal procedures received 1.0 ml hyperbaric bupivacaine (0.5%). On request, a light sedation with propofol in bolus application was provided. Patients were evaluated postoperatively using a standardized questionnaire about their perceptions before, during and 48 h after the administration of anaesthesia. RESULTS: More female (91/143, 63.6%) than male (136/259, 52.5%) patients (p = 0.0312) received sedation. Patients with sedation were significantly younger (46.7 +/- 13.8 vs. 50 +/- 13.8 years, p = 0.0171) and had a lower body mass index (BMI; 25.6 +/- 4.3 vs. 27.5 +/- 5.1, p < 0.0001). Time to mobilization and first micturition was significantly longer in patients with sedation (4.8 vs. 4.4 h, p = 0.0194 and 5.8 vs. 5.4 h, p = 0.0188), which was associated with a higher incidence of nausea (7.5 vs. 1.7%, p = 0.0083). CONCLUSIONS: Female gender, younger age, lower body weight and lower BMI were associated with higher subjective requirements for sedation. The use of sedation showed prolongation of time to first mobilization and micturition and a higher incidence of nausea.

Practicability and patients' subjective experiences of low-dose spinal anaesthesia using hyperbaric bupivacaine for transanal surgery.

PURPOSE: The safety, effectiveness and long lasting post-operative analgesia make spinal anaesthesia in saddle block technique an "ideal" method for transanal surgery. To improve patient satisfaction and offer reliable operation conditions to surgeons, this study quantifies practicability and patients' subjective experiences with this technique. METHODS: Within a 5-month period, 400 consecutive patients undergoing transanal surgery in saddle block technique were evaluated by a standardised questionnaire. RESULTS: The success rate of spinal anaesthesia was 99.5%. Side effects occurred far less frequently as mentioned in the literature. The duration of the sensory block was about twice as long as the time until first mobilisation and micturition. Despite some negative experiences during the procedure, 92% of the investigated patients would choose a saddle block again. CONCLUSIONS: Both from reasons of practicability and from patients' view, spinal anaesthesia in saddle block technique can be thoroughly recommended for transanal surgery. Patients undergoing a stapler haemorrhoidectomy should receive additional opioids.

Effects of fentanyl and S(+)-ketamine on cerebral hemodynamics, gastrointestinal motility, and need of vasopressors in patients with intracranial pathologies: a pilot study.

In neurosurgical patients, opioids are administered to prevent secondary cerebral damage. Complications often related to the administration of opioids are a decrease in blood pressure affording the use of vasopressors and intestinal atonia. One alternative approach to opioids is the application of S(+)-ketamine. However, owing to a suspected elevation of intracranial pressure (ICP), the administration of S(+)-ketamine has questioned for a long time. The aim of the present study was to evaluate ICP, gastrointestinal motility, and catecholamine consumption in neurosurgical patients undergoing 2 different protocols of anesthesia using fentanyl or S(+)-ketamine. Twenty-four patients sustaining traumatic brain injury or aneurysmal subarachnoid hemorrhage received methohexitone plus either fentanyl or S(+)-ketamine to establish a comparable level of sedation. To reach an adequate cerebral perfusion pressure (CPP), the norepinephrine dosage was adapted successively. Enteral nutrition and gastrointestinal stimulation were started directly after admission on the critical care unit. ICP, CPP, and norepinephrine dosage were recorded over 5 days and also the time intervals to full enteral nutrition and first defecation. There was no difference regarding ICP, CPP, and the time period until full enteral nutrition or first defecation between both groups. Patients who underwent analgesia with S(+)-ketamine showed a trend to a lower demand of norepinephrine compared with the fentanyl group. Our results indicate that S(+)-ketamine does not increase ICP and that its use in neurosurgical patients should not be discouraged on the basis of ICP-related concerns.

Comparison of different inhalational perfluorocarbons in a rabbit model of acute lung injury.

The purpose of this study was to investigate the influence of different inhaled perfluorocarbons (PFC) upon pulmonary mechanics and gas exchange in a saline lavage model of acute lung injury. A randomized, controlled animal trial was conducted at the university hospital laboratory. Pulmonary gas exchange (pGE), static compliance (Cst), and basic hemodynamics (heart rate [HR], arterial [AP] and central venous pressures [CVP]) were compared. After induction of lung injury by repeated pulmonary lavage with saline solution, 35 New Zealand rabbits (3 +/- 0.2 kg) were randomized into five groups with seven animals each: 1) conventional ventilated control, 2) perfluorooctane (octane), 3) Perflubron (perfluorooctylbromide [PFOB]), 4) Perfluoro-1,3,5-trimethylcyclohexane (PP 4), and 5) perfluorohexane (hexane). Consecutively, PFC groups were subjected to a 120 minute study period applying mechanical ventilation (tidal volume of 7 ml/kg) in conjunction with PFC performed by a modified halothane vaporizer. Amount of vaporization was controlled by weighing the vaporizer at approximately 25 ml/h/kg body-weight PFC. Controls remained gas ventilated. After injury, PaO2 was control = 53 +/- 13 mbar, octane = 55 +/- 24 mbar, perflubron = 57 +/- 18 mbar, PP4 = 68 +/- 25 mbar, and hexane = 51 +/- 16 mbar. Within the 120 minute period, PaO2 was control = 51 +/- 19 mbar, octane = 42 +/- 6 mbar, perflubron = 40 +/- 11 mbar, PP4 = 47 +/- 10 mbar, and hexane = 60 +/- 8 mbar, respectively. At baseline, after injury, and throughout the study period, pGE and Cst, as well as HR, AP, and CVP, did not significantly differ when compared with octane, PP4, PFOB, and controls (p > 0.05), whereas hexane significantly improved pGE and Cst (p < 0.05). From four different inhaled perfluorocarbons, only perfluorohexane has measureable impact upon gas exchange and lung mechanics when compared with a conventional lung protective ventilation mode.

Measurements of alveolar pO2 using 19F-MRI in partial liquid ventilation.

RATIONALE AND OBJECTIVES: Partial liquid ventilation using Perfluorcarbon (PFC) is an innovative treatment of acute respiratory distress syndrome. However, the underlying mechanisms are not totally clear. The aim was to investigate the distribution of oxygen partial pressure within the PFC-filled lung (ppO2). METHODS: Nine pigs underwent partial liquid ventilation, receiving 20 mL PFC/kg bodyweight (bw). Measurements were obtained by a chemical shift selective TurboFLASH sequence at different axial lung levels. ppO2 was calculated from 19F-MRI by nonlinear curve T1-fitting technique after noise correction. RESULTS: Quantification and distribution of ppO2 was performed successfully. A narrow relationship of the inspiratory O2 fraction and ppO2, as well as a significant ventral-to-dorsal gradient of ppO2 (ventral:dependent lung = 1.9:1) were detected in all subjects and slice positions. CONCLUSIONS: In vivo measurement of local ppO2 gains new and clinical important insights into the physiology of PLV. The previously unknown ppO2 gradient within PFC fits to distribution of perfusion. Dependent lung regions appear to have limited access to O2 from central airways.