Supplemental single shot femoral nerve block for total hip arthroplasty: impact on early postoperative care, pain management and lung function

BACKGROUND AND AIM

Peripheral regional anesthesia is beneficial in the management of postoperative pain in hip surgery, and can also reduce post-operative care unit (PACU) stay. Its opioid-sparing actions may also be beneficial for respiratory mechanics and pulmonary function. The aim of our pilot study was to evaluate the effect of a supplemental single shot femoral block for elective total hip arthroplasty on early respiratory function and postoperative management within the first 24 postoperative hours.

METHODS

We prospectively studied 80 patients undergoing total hip arthroplasty. Written informed consent was obtained after ethics committee approval. Forty patients were randomLy assigned to receive single shot femoral nerve block (FNB) using 15mL bupivacaine 0.25% and 20 mg clonidine while the remainder received standard treatment without nerve block (STN). Premedication and general anesthesia were standardized. Pulse oximetry saturation and spirometric lung function were measured preoperatively (baseline) and at 0.5 h, 2 h, 6 h and 24 h, after extubation breathing room air. PACU surveillance and postoperative pain therapy was standardized.

RESULTS

Oxygen saturation and spirometry results were significantly better within the FNB group during the first six postoperative hours. Although VAS scores during the PACU stay did not significantly differ between the study groups, PACU discharge criteria were met earlier in the FNB group (116±40 min [mean±SD] vs. 152±47 min in the STN group). The FNB group exhibited significantly lower VAS scores at 6 and 24 hours.

CONCLUSION

Supplemental single shot femoral nerve block for total hip arthroplasty resulted in earlier PACU discharge capability, improved lung function during the first six hours and better pain control within the first 24 postoperative hours.

Airtightness of lung parenchyma without a closing suture after atypical resection using the Nd:YAG Laser LIMAX 120

OBJECTIVES

Lung metastases can be non-anatomically resected with a Nd:YAG Laser. It is recommended that the resected lung surface be sealed by slowly resorbable sutures. However, the lung tissue may be restricted by the sutures once it is re-ventilated. Thus, it was analysed whether the lung parenchyma is airtight after laser resection without suturing the defect.

METHODS

The pulmonary artery of unimpaired paracardial lung lobes of freshly slaughtered pigs (mean weight 46 g) was cannulated and rinsed out via a hypotonic saline-heparin solution (5000 IE) until the perfusate was clear of body fluid. The lobular bronchus was connected to an airtight ventilation tube (Fa. VYGON 520 3.5 oral tube) and ventilated pressure-controlled (PEEP + 5 cm H₂O, P₁ = 20 cm H₂O, frequency = 10/min) via a respirator. All lobes were perfused with Ringer solution at 42°C at normothermia and normotonia. In group 1 (n = 8), an atypical peripheral parenchymal resection (average resected surface: 2 × 2 cm(2)) and in group 2 (n = 8), a deep atypical parenchymal resection (average resected surface: 4 × 4 cm(2)) were performed with the Nd:YAG Laser LIMAX 120 (output power at 100 watts). After post-resection ventilation of 15 min, the resection surface was tested for airtightness and burst pressure.

RESULTS

All group 1 lobes tested airtight under pressure-controlled ventilation. The mean burst pressure was 34.4 mbar (SD ± 3.2 mbar). Six lobes of group 2 were also completely airtight. The remaining two lobes, however, revealed a serious parenchymal leak (score 3). This was caused by the cross-opening of a segmental bronchus, although the surrounding lung parenchyma was also airtight. The mean burst pressure of these lobes was 31.7 mbar (SD ± 4.08 mbar). There was no significant difference between the two groups (P = 0.12).

CONCLUSIONS

Peripheral lung defects after Nd:YAG Laser resection might not be sutured, since the laser-induced vaporization of the lung parenchyma seems to be initially airtight. These experimental data warrant confirmation in a controlled clinical study.

Occurrence of rapid eye movement sleep deprivation after surgery under regional anesthesia

BACKGROUND

Sleep disturbances after general surgery have been described. In this study, we assessed rapid eye movement (REM) sleep in patients undergoing knee replacement surgery using a regional anesthetic technique.

METHODS

Ambulatory polysomnography (PSG) was performed on 3 nights: the night before surgery (PSG1), the first night after surgery (PSG2), and the fifth postoperative night (PSG3). Postoperative analgesia was maintained with peripheral nerve catheters for the first 3 days and with oral opioids thereafter. In addition, nonsteroidal antiinflammatory drugs were administered. Postoperative pain was monitored using a visual analog scale.

RESULTS

PSG was performed in 12 patients, 6 men and 6 women, with a mean age of 61 (±12) years. REM sleep was reduced from PSG1 (median 16.4%) to PSG2 (median 6.3%; P = 0.02). The Hodges-Lehmann estimate for the median reduction is -7.8% (95% confidence interval -14.8% to -0.7%). During PSG3, significantly more REM sleep was detected (median 15.4%) compared with PSG2 (P = 0.01). The Hodges-Lehmann estimate for this median increase is 10.0% (95% confidence interval 1.7%-25.3%).

CONCLUSION

Postoperative reduction of REM sleep also occurs after surgery and regional anesthesia.

Videolaryngoscopy with glidescope reduces cervical spine movement in patients with unsecured cervical spine

BACKGROUND

Unconscious patients with severe trauma often require urgent endotracheal intubation. In trauma victims with possible cervical spine injury, any movement of the head and neck should be avoided.

STUDY OBJECTIVES

We investigated the effect of GlideScope videolaryngoscopy on cervical spine movement compared with conventional laryngoscopy in anesthetized patients with unsecured cervical spines.

METHODS

Sixty patients scheduled for elective surgery with general anesthesia and without anticipated airway problems were enrolled in the study after ethics committee approval and written informed consent. Intubation was performed with videolaryngoscopy (GlideScope(®), Verathon Inc., Bothell, WA) or conventional laryngoscopy (MacIntosh). Using video motion analysis with a lateral view, the maximum extension angle α was measured with reference to anatomical points (baseline and line drawn from processus mastoideus to os frontale [glabella]). Values were analyzed using Mann Whitney U-tests.

RESULTS

The deviation of α was a median 11.8° in the videolaryngoscope group and 14.3° in the conventional group (p = 0.045), with a maximum of 19.2° (videolaryngoscopy) vs. 29.3° (conventional). Intubation by physicians with some experience in videolaryngoscopy was associated with a reduced angle deviation (α = 10.3°) compared to inexperienced physicians (12.8°, p = 0.019). Intubation time was a median 24 s (min/max 12/75 s) in the MacIntosh group and 53 s (min/max 28/210 s) in the GlideScope group. In 3 patients randomized to the conventional group in whom conventional intubation failed, intubation could be successfully performed using videolaryngoscopy.

CONCLUSION

GlideScope videolaryngoscopy reduces movements of the cervical spine in patients with unsecured cervical spines and therefore might reduce the risk of secondary damage during emergency intubation of patients with cervical spine trauma.

Transoral thyroid and parathyroid surgery--development of a new transoral technique

BACKGROUND

Transluminal interventions via so-called natural orifices are gaining interest because they allow operative treatment without any skin incision. We previously described a transoral access for (para-)thyroid resection in pigs. To proceed with the first clinical trials, we evaluated the safety of the new technique.

METHODS

Transoral hemithyroidectomies were performed on 10 living pigs using a special cervicoscope and conventional laparoscopic instruments. Follow-up examinations were carried out for 14 days and followed by autopsy, which included macroscopic evaluation, microbiologic investigations, and blood testing. In addition, refinement of the new technique was achieved by developing the techniques in 10 human cadavers. Finally, transoral parathyroidectomies were performed in 2 patients with primary hyperparathyroidism and a preoperatively localized parathyroid adenoma.

RESULTS

All animal transoral hemithyroidectomies were performed without complications. Postoperatively, oral intake, weight gain, and white blood cell count remained normal. At autopsy, the access route, and operative field showed no signs of infection, and microbiologic swabs remained sterile. Based on these results, a transoral parathyroidectomy was performed successfully in 2 female patients with primary hyperparathyroidism; 1 patient experienced a transient palsy of the right hypoglossal nerve.

CONCLUSION

Transoral parathyroid and thyroid operation is feasible; however, additional controlled clinical studies are required to evaluate the safety and success rates of this new technique.

Nerve perforation with pencil point or short bevelled needles: histological outcome

BACKGROUND

In the case of needle nerve contact during peripheral blocks, pencil point needles are considered less traumatic compared with bevelled needles. However, there are not enough data to prove this notion. Therefore, the aim of this study was to challenge the hypothesis that nerve perforation with short bevelled needles is associated with major nerve damage compared with pencil point needles.

METHODS

In five anaesthetised pigs, the brachial plexus was exposed bilaterally. Up to eight nerves underwent needle nerve perforation using a pencil point needles cannula or an short bevelled needle. After 48 h, the nerves were resected. The specimens were processed for visual examination and the detection of inflammatory cells (haematoxylin-eosin, i.e. CD68-immunohistochemistry to detect macrophages), myelin damage (Kluver-Barrera staining) and intraneural haematoma. The grade of nerve injury was characterised by an objective score ranging from 0 (no injury) to 4 (severe injury).

RESULTS

Fifty nerves were examined. According to the injury score applied, there was no significant difference between the pencil point needles [median (inter-quartile range) 2.0 (2.0-2.0)] and the short bevelled-needle group [median 2.0 (2.0-2.0) P=0.23]. No myelin damage was observed. Signs of post-traumatic inflammation were equally distributed among both groups.

CONCLUSIONS

In the present study, the magnitude of nerve injury after needle nerve perforation was not related to one of the applied needle types. Post-traumatic inflammation rather than structural damage of nerve tissue is the only notable sign of nerve injury after needle nerve perforation with either needle type. However, neither the pencil point- nor the short bevelled needle can be designated a less traumatic device.

Systematic evaluation of the highest current threshold for regional anaesthesia in a porcine model

BACKGROUND

The purpose of this study was to determine systematically the highest minimal stimulation current threshold for regional anaesthesia in pigs.

METHODS

In an established pig model for regional anaesthesia, needle placements applying electric nerve stimulation were performed. The primary outcome was the frequency of close needle to nerve placements as assessed by resin injects and subsequent anatomical evaluation. Following a statistical model (continual reassessment method), the applied output currents were selected to limit the necessary number of punctures, while providing guidance towards the highest output current range.

RESULTS

Altogether 186 punctures were performed in 11 pigs. Within the range of 0.3-1.4 mA, no distant needle to nerve placement was found. In the range of 1.5-4.1 mA, 43 distant needle to nerve placements occurred. The range of 1.2-1.4 mA was the highest interval that resulted in a close needle to nerve placement rate of > or =95%.

CONCLUSIONS

In the range of 0.3-1.4 mA, all resin deposition was found to be adjacent to nerve epineurium. The application of minimal current intensities up to 1.4 mA does not obviously lead to a reduction of epineural injectate contacts in pigs. These findings suggest that stimulation current thresholds up to 1.4 mA result in equivalent needle tip localisation in pigs.

Femoral nerve block with ropivacaine or bupivacaine in day case anterior crucial ligament reconstruction

BACKGROUND/OBJECTIVE

Our aim was to evaluate analgesia, motor block and pharmacokinetics of ropivacaine 0.2% and 0.75% in a femoral nerve block (FNB) in day case patients for anterior crucial ligament (ACL)-reconstruction compared with bupivacaine 0.25% and placebo.

METHODS

Following ethics committee approval and informed consent, 280 patients were randomly allocated to four groups for single-shot FNB [30 ml ropivacaine 0.2% (group RO2.0), 0.75% (RO7.5), bupivacaine 0.25% (BU2.5) and NaCl 0.9% (NaCl)]. Analgesia (pain scores, primary outcome) and motor block were assessed at 4 h (dismissal) and up to 24 h. Plasma concentration was determined up to 240 min thereafter.

RESULTS

Pain scores at 4 h were significantly higher for NaCl 4 (0-8) (median, range) (vs.) BU2.5 2 (0-8), RO2.0 3 (0-9) and RO7.5 2 (0-8) (NS within the LA groups). Patients of the NaCl group needed analgesics significantly more often (93%) within 4 h after surgery vs. 16% of group RO2.0, 19% of group RO7.5 and 19% of group BU2.5. Motor block was significantly increased with all local anesthetics without a significant difference within the LA groups 3 (0-5) in RO2.0, 3 (0-5) in RO7.5 and 3 (0-4) in BU2.5 vs. 0 (0-3) in group NaCl (median (range); scale from 0=full strength to 5=complete paralysis). Peak plasma concentrations differed significantly: RO7.5: 1.4 +/- 0.4 (0.73-2.6) [microg/ml, mean +/- SD (range)] after 33 +/- 14 (10-40) min, RO2.0: 0.6 +/- 0.3 (0.13-1.0) after 22+17 (10-60) and BU2.5: 0.3 +/- 0.16 (0.05-0.62) at 31 +/- 17 (10-60), respectively.

CONCLUSION

FNB for ACL reconstruction with ropivacaine or bupivacaine provided better post-operative analgesia than placebo without reaching toxic plasma concentrations. Significant motor block was observed after 4 h in all groups including the lowest concentration of ropivacaine but occurred even with placebo.

Transoral thyroid and parathyroid surgery

BACKGROUND

Translumenal endoscopic interventions via so-called natural orifices are gaining increasing interest because they allow surgical treatment without any incision of the skin. Moreover, minimally invasive procedures have found their way into thyroid and parathyroid surgery. Our goal was to develop a new access for thyroid and parathyroid resection via an entirely transoral approach.

METHODS

We managed to find an entirely transoral sublingual access to the thyroid region in pigs and human cadavers. Using a modified rigid rectoscope (oraloscope) hemithyroidectomies as well as resection of parathyroid glands were performed via this new approach. Preparation and resection was performed using conventional laparoscopic instruments. In living pigs, integrity of the recurrent laryngeal nerve after resection could be documented by neuromonitoring. An absorbable suture was used to seal the mucosal incision.

RESULTS

First, hemithyroidectomy was performed via the transoral access in 10 porcine cadavers, then in 10 living and orally intubated pigs, and finally in five human corpses. In humans, resection of parathyroid glands also was performed. We gained access to the thyroid region by blunt dissection of the layer behind the hyoid bone and the strap muscles of the neck. We did not observe any complication during the insertion, resection, and removal part of the new procedure.

CONCLUSIONS

Entirely transoral thyroid and parathyroid surgery via sublingual access seems to be feasible. However, further investigations are needed to evaluate the safety of the new technique, especially potential and clinically relevant contamination of the access route has to be excluded.

High or low current threshold for nerve stimulation for regional anaesthesia

BACKGROUND

The purpose of this study was to determine whether the application of high stimulation current thresholds (SCT) leads to a distant needle to nerve proximity (NNP) compared with low SCT during nerve localization for regional anaesthesia in pigs.

METHODS

A minimal motor response to the stimulation of femoral or brachial plexus nerves in 16 anaesthetized pigs was triggered either by a minimal SCT of a low (0.01-0.3 mA) or a high (0.8-1.0 mA) current in a random order. After eliciting a motor response with a predetermined SCT, synthetic resin was injected via the needle. After postmortem dissection of the injection site, the localization of the resin deposition was determined verifying the final position of the needle tip. Depending on the proximity of resin deposition to the nerve epineurium, the needle tip placement was considered either as a close or a distant NNP.

RESULTS

A total of 235 punctures were performed. Ninety-one punctures were carried out with low SCT and 92 with a high SCT. Fifty-two punctures served as a control (1.8-2.0 mA). All injectates following both high or low SCT were considered 'close needle tip to nerve placement', whereas 27 of 52 injectates of the control group appeared distant to nerve epineurium.

CONCLUSION

Regardless of the applied SCT, i.e. high or low, all resin deposition was found adjacent to nerve epineurium. These findings suggest that high and low SCT result in equivalent needle tip localization in pigs.

Basic life support with four different compression/ventilation ratios in a pig model: the need for ventilation

BACKGROUND

During cardiac arrest the paramount goal of basic life support (BLS) is the oxygenation of vital organs. Current recommendations are to combine chest compressions with ventilation in a fixed ratio of 30:2; however the optimum compression/ventilation ratio is still debatable. In our study we compared four different compression/ventilation ratios and documented their effects on the return of spontaneous circulation (ROSC), gas exchange, cerebral tissue oxygenation and haemodynamics in a pig model.

METHODS

Study was performed on 32 pigs under general anaesthesia with endotracheal intubation. Arterial and central venous lines were inserted. For continuous cerebral tissue oxygenation a Licox PtiO(2) probe was implanted. After 3 min of cardiac arrest (ventricular fibrillation) animals were randomized to a compression/ventilation-ratio 30:2, 100:5, 100:2 or compressions-only. Subsequently 10 min BLS, Advanced Life Support (ALS) was performed (100%O(2), 3 defibrillations, 1mg adrenaline i.v.). Data were analyzed with 2-factorial ANOVA.

RESULTS

ROSC was achieved in 4/8 (30:2), 5/8 (100:5), 2/8 (100:2) and 0/8 (compr-only) pigs. During BLS, PaCO(2) increased to 55 mm Hg (30:2), 68 mm Hg (100:5; p=0.0001), 66 mm Hg (100:2; p=0.002) and 72 mm Hg (compr-only; p<0.0001). PaO(2) decreased to 58 mmg (30:2), 40 mm Hg (100:5; p=0.15), 43 mm Hg (100:2; p=0.04) and 26 mm Hg (compr-only; p<0.0001). PtiO(2) baseline values were 12.7, 12.0, 11.1 and 10.0 mm Hg and decreased to 8.1 mm Hg (30:2), 4.1 mm Hg (100:5; p=0.08), 4.3 mm Hg (100:2; p=0.04), and 4.5 mm Hg (compr-only; p=0.69).

CONCLUSIONS

During BLS, a compression/ventilation-ratio of 100:5 seems to be equivalent to 30:2, while ratios of 100:2 or compressions-only detoriate peripheral arterial oxygenation and reduce the chance for ROSC.

[Heparin induced thrombocytopenia and anticoagulation in renal replacemant therapy]

The decision for an anticoagulant for renal replacement therapy (RRT) in patients with acute renal failure and heparin-induced thrombocytopenia (HIT) has to be made carefully. Based on results from the literature argatroban is favoured in patients without hepatic dysfunction, referring to its short halftime and easy feasable monitoring. In the case of coexsisting hepatic disorder, danaparoid provides a safe alternative therapy. However, long halftime and the difficult elimination of the substance are unfavourable. Lepirudin represents another possible anticoagulant therapy. Bleeding complications and monitoring of the ecarin clotting time imposes limitations. Experiences with bivalirudin, fondaparinux and prostaglandines are limited and future trials will have to determine the significance of their application in RRT in HIT patients. Furthermore it has to be proven whether the combination of alternative anticoagulants with citrate prolongates circuit halftime of CVVH.

Analgetikakombinationen zur postoperativen Schmerztherapie

BACKGROUND

The supplementation of an opioid by a non-opioid analgesic is a widely accepted technique for the treatment of postoperative pain. However, it is still unclear whether a combination of different non-opioids has an advantage in terms of an improved analgesia and/or a reduction of the opioid-related adverse effects.

METHODOLOGY

A systematic analysis of the literature was performed searching for randomized, controlled trials studying the effects of a combination of two non-opioid analgesics in order to reduce postoperative opioid requirements and/or postoperative pain. Significant reduction of the postoperative opioid requirement and/or postoperative pain were defined as main rating criteria. To facilitate comparisons between the trials, the relative (proportional) reduction of postoperative opioid administration and the relative reduction of postoperative pain were calculated on defined pain scales.

RESULTS

A total of 25 trials were identified, mainly studies comparing non-steroidal anti-inflammatory drugs (NSAIDs) with paracetamol. Only 3 trials found a statistically improved analgesic efficacy and 15 studies did not show any relevant improvement or the combination group was only significantly superior to one of the groups receiving monotherapy. A further seven studies could not be evaluated due to methodological issues. There was no evidence for a significant reduction of opioid-induced adverse effects.

CONCLUSION

A combination of non-opioid analgesics, in particular NSAIDs with paracetamol, cannot be recommended at present due to the lack of data showing improved effectiveness.

[Stimulating catheters for regional anesthesia: considerations in routine clinical use]

The use of peripheral catheter techniques for regional anaesthesia and analgesia is quite common today. Although electrical nerve stimulation facilitates the correct placement of the insertion cannula, nobody knows where exactly the tip of the advanced catheter will be located after insertion. With the help of stimulation nerve catheters the stimulation of the target nerve via the tip of the catheter during insertion enables a placement nearby the nerve without additional devices. These new catheter systems require--in comparison to the conventional--a modified insertion technique. This article illustrates how to use these catheters in clinical practice and provides information about investigations to success rate and failure.

[Anaesthesia education at german university hospitals: the teachers' perspective -- results of a nationwide survey]

AIM OF THIS STUDY

The principle purpose of this study was to collect data on the conditions and practice of anaesthesia education as well as the teaching qualification of consultants at German university hospitals. Based upon the collected data, areas of weakness and strength as well as measures required to improve anaesthesia training are described.

METHODS

A questionnaire containing 26 items was mailed to 607 consultants employed at 41 German university hospitals in June 2003.

RESULTS

A total of 255 questionnaires was analysed (response rate: 43 %). Genuine training activities account for 14 % of the working hours of the participating consultants. On average, at the institutions of participating consultants, novices work for a duration of 1 month together with a consultant anaesthetist before they give anaesthetics without direct and constant supervision. When asked to describe the predominant method of training at their institution 71 % indicated "case-oriented teaching"; however, 53 % chose "see one, do one, teach one" and 49 % "learning by doing" as method of training as well (multiple choice). According to 63 % of respondents, departmental educational activities usually happen after their regular working hours. "Daily workload" (96 %), "time pressure" (96 %), "lack of time" (96 %) and "lack of personnel" (90 %) were indicated as the main obstacles of teaching. According to 80 % of respondents, a dedicated financial budget for education does not exist; instead, financial resources of third parties (industry) (58 %), of the state (for research und undergraduate education) (60 %) and of patients service (66 %) are used to ensure training of anaesthesia residents.

CONCLUSION

Due to a lack of a dedicated financial budget for resident training and an increasing economic pressure, "lack of time" and "lack of personnel" are the main factors leading to the situation at German university hospitals that consultants can only spend 14 % of their working hours for teaching purposes despite of sufficient qualification and motivation. As a consequence, novice anaesthetists are faced with the situation to be working without direct and constant supervision after 1 month of training.

Acquisition of basic fiberoptic intubation skills with a virtual reality airway simulator

STUDY OBJECTIVE

To test the hypothesis that a virtual reality (VR) airway simulator (the AccuTouch Virtual Reality Bronchsocopy Simulator; Immersion Medical, Gaithersburg, MD) can be used to teach residents basic fiberoptic intubation (FOI) skills effectively.

DESIGN

Observational study.

SETTING

University anesthesiology department.

INTERVENTION

Supervised training was done using a VR airway simulator.

MEASUREMENTS

Time to intubation before and after a 4-day training period using an adult VR FOI scenario and time to intubation using a fresh human cadaver two weeks after the training experience were measured.

MAIN RESULTS

Residents were able to significantly improve time to intubation in the VR scenario (114 vs 75 seconds; P = 0.001). Novices differed from experienced attending anesthesiologists in time to intubation in the VR scenario, before but not after training (114 vs 79 seconds compared with 75 vs 72 seconds). Novices who had been trained with the simulator performed significantly faster in the cadaver than novices who had not (24 vs 86 seconds; P < 0.001). Furthermore, there was no difference in time to intubation in the cadaver between trained novices and experienced attending anesthesiologists (24 vs 23 seconds; P > 0.05).

CONCLUSION

Use of a VR airway simulator enables anesthesia residents to acquire basic FOI skills comparable to those of experienced anesthesiologists in a human cadaver.

Videolaryngoskopie zur modifizierten „Rapid-sequence-Narkoseeinleitung“

BACKGROUND

There is evidence that cricoid pressure, one of the key elements of rapid sequence induction (RSI) in patients at risk of aspiration, can distort the glottic view obtained by direct laryngoscopy (DL) and consequently impair or delay endotracheal intubation (ETI). The fact that cricoid pressure is applied by an assistant "blindly", i.e. without any visual feedback, is believed to be a contributing factor. Video laryngoscopy (VIL) offers the advantage that both the anaesthetist and the assistant can follow laryngoscopy. This could be useful for ETI during RSI.

METHODS

We used VIL for a simulated RSI in 170 adult patients randomised to either video laryngoscopy-guided application of cricoid pressure (group I) or conventional, i.e. "blind", application of cricoid pressure (group II). Time to ETI was compared between groups. The laryngoscopy view obtained by VIL was compared with the view of conventional DL obtained before, in all patients.

RESULTS

Time to ETI did not differ between groups (p=0.2): 25.1+/-14.2 s (group I) vs. 23.7+/-12.1 s (group II). Laryngoscopy scores were significantly better for VIL than conventional DL (p<0.001).

CONCLUSIONS

Visualisation of the larynx during RSI can be improved using VIL. Time to ETI is not decreased by use of video laryngoscopy-guided application of cricoid pressure.

Analysis of the subcellular localization of the proteins Rep, Rep' and Cap of porcine circovirus type 1

Porcine circovirus type 1 (PCV1) encodes two major ORFs. The cap gene comprises the major structural protein of PCV, the rep gene specifies Rep and Rep', which are both essential for initiating the replication of the viral DNA. Rep corresponds to the full-length protein, whereas Rep' is a truncated splice product that is frame-shifted in its C-terminal sequence. In this study, the cellular localization of PCV1-encoded proteins was investigated by immune fluorescence techniques using antibodies against Rep, Rep' and Cap and by expression of viral proteins fused to green and red fluorescence proteins. Rep and Rep' protein co-localized in the nucleus of infected cells as well as in cells transfected with plasmids expressing Rep and Rep' fused to fluorescence proteins, but no signal was seen in the nucleoli. Rep and Rep' carry three potential nuclear localization signals in their identical N-termini, and the contribution of these motifs to nuclear import was experimentally dissected. In contrast to the rep gene products, the localization of the Cap protein varied. While the Cap protein was restricted to the nucleoli in plasmid-transfected cells and was also localized in the nucleoli at an early stage of PCV1 infection, it was seen in the nucleoplasm and the cytoplasm later in infection, suggesting that a shuttling between distinct cellular compartments occurs.

Rep and Rep' protein of porcine circovirus type 1 bind to the origin of replication in vitro

Genome replication of Porcine circovirus type 1 (PCV1) relies upon expression of the full-length protein Rep and a spliced isoform (Rep'), and the presence of a 111-bp genomic fragment comprising the origin of replication. Using an electrophoretic mobility shift assay (EMSA), the capability of both Rep proteins to bind to partial fragments of the origin of replication of PCV1 was investigated in vitro. Both proteins formed complexes with double-stranded DNA origin fragments containing a stem-loop structure with a conserved nonamer and four hexamer repeats (5'-CGGCAG; H1 to H4). Use of truncated EMSA substrates identified minimal binding sites (MBS) for Rep and Rep' protein: The Rep binding site was mapped to the right leg of the stem-loop and the two inner hexamer repeats H1/H2, while binding of Rep' required only the presence of two hexamer repeats. Two differentially retarded complexes were observed with Rep protein, which presumably result from alternative binding to the MBS or to H3/4.