The "preoxygenation" special function in mechanical ventilators. Medically necessary and an ergonomic plus?

Hypoxia-related cardiovascular complications and unnecessary monitor and ventilator alarms are well-known problems during tracheobronchial suctioning. Preoxygenation together with temporary muting of acoustic alarms for tracheobronchial suctioning are provided by a single operational control of the ventilator "Evita", software release 9 (Dr?gerwerk AG). This integrated function was evaluated in medical and ergonomic respects. METHODS. Thirty tracheobronchial suctioning procedures each, with or without preoxygenation, were evaluated. The subjects were patients in our anesthesiological intensive care unit who were under continuous positive-pressure ventilation with FIO2 between 0.25 and 0.6. They ranged in age from 18 months to 72 years. Each patient served as her/his own control after about 1-h delays. Depending on the preference of the nurse, the procedures were either both on-ventilator (via the catheter port) or both off-ventilator suctionings. Arterial samples for blood gas analyses as well as arterial oxygen saturation (SaO2) determinations were taken before preoxygenation, at the moment of disconnection or opening of the catheter port, at reconnection or closure of the port, and 5 min later. Moreover, the number of changes in position of the performing nurse, the number of acoustic ventilator alarms, and the duration of the procedure were recorded. Finally, assessments of the integrated ventilator feature by the 28 participating nurses were collected both as a score from 1 ("most useful and innovative") to 5 ("completely superfluous and distracting") and as detailed statements. RESULTS. Arterial blood gas results and SaO2 courses differentiated as to procedures with or without preoxygenation as well as on-ventilator and off-ventilator suctioning are shown in Table 1 (values are mean +/- standard deviation). Without preoxygenation, most patients did not exhibit threatening drops in SaO2 (values fell from 98.2%) to 97.0% on the average). Nevertheless, preoxygenation provided an additional safety margin (100% saturation throughout the procedure in all patients). Under certain conditions, e.g., low functional residual capacity as in small children or patients with adult respiratory distress syndrome (in 1 of these cases we observed a SaO2 drop to 87%), it is mandatory. Although occurring far less frequently, unnecessary acoustic alarms were not completely excluded by the integrated function because the ventilator would not recognize the insertion of the suction catheter via the catheter port as the expected disconnection. Thus, coughing was able to trigger the "high airway pressure" alarm. As expressed by an average score of 2.8, approval of the integrated ventilator function prevailed among the involved nursing staff.     

Einfluß verschiedener niedriger Droperidol-Dosierungen auf postoperative Angst, innere Anspannung, allgemeine Befindlichkeit und PONV

Background: Droperidol even in low doses such as 0,5?mg to 1,25?mg can increase postoperative anxiety and state of tension. The aim of this study was to determine whether these side effects occur frequently following low-dose droperidol and to see whether these are dose related. Methods: 184 female in- and outpatients ASA grade 1 and 2 undergoing gynaecological laparoscopy were recruited to this prospective, double-blind study. General anaesthesia was standardized (induction with thiopentone, fentanyl 2?µg/kg and vecuronium 0,1?mg/kg, tracheal intubation, maintainance with enflurane in N₂O/O₂). Patients were randomly allocated to receive saline (n=45), 0,625?mg (n=46), 1,25?mg (n=47) or 2,5?mg (n=46) droperidol i.v. 10 minutes before the end of surgery. 1, 3, 6, and 24 hours postoperatively, the patients’ anxiety, state of tension and overall mood was evaluated using two psychological questionnaires which had been tested for the perioperative period (Erlanger anxiety and tension-scale / BSKE-EWL-test). Sedation was evaluated by the staff of the recovery room. In addition, postoperative nausea and vomiting (PONV) was assessed using a 100?mm visual analogue scale and by counting the episodes of retching or vomiting. PONV was then rated over the whole observation period as none, mild, moderate or severe using a fixed scoring algorithm. Statistical analysis was performed using the ANOVA and the chi²-test. Results: The patients did not differ with regard to biometric data, duration of surgery and anaesthesia. The postoperative scores for anxiety, state of tension and overall mood were not different between the groups at any observation time (Fig.?1: anxiety and tension: P=0,5687; figure 2: overall mood: P=0,0647). Quality of sleep in the first night after surgery was the same in all groups (Table?2 and 3). Sedation was not significantly different (Table?4; P=0,0704). Furthermore, duration of stay in the recovery room did not differ (P=0,4353). On the other hand, three patients from the 2,5?mg droperidol group had to stay unexpectedly on the ward overnight, because they had been too much sedated to be discharged at home. This was not the case with any patient from the other groups. Compared to placebo, PONV over the whole 24?h observation period was significantly reduced by droperidol (Fig.?3; P=0,0338): completely free from PONV: placebo: 41,3%, 0,625?mg droperidol: 67,4%, 1,25?mg droperidol: 53,2%, 2,5?mg droperidol: 71,7%. Also the severity of PONV was reduced. Conclusion: In gynaecological laparoscopy under general anaesthesia with tracheal intubation, we recommend droperidol 0,625?mg in the prevention of PONV, as it reduces PONV as well as 2,5?mg with no severe sedation in this dosage. Psychological side effects did not occur more frequently after droperidol compared to placebo in any of the investigated dosages.     

Arthroscopic therapy of patellar luxation. Operative technique and clinical results Operationstechnik und klinische Ergebnisse

Between January 1986 and August 1995, we treated 86 patients suffering from lateral displacement of the patella with arthroscopic medial tightening and lateral release after a conservative functional treatment remained unsuccessful. 49 patients were available for follow-up studies. 29 patients were treated after primary dislocation of the patella, and 20 patients after recurrent dislocations (2–20). The lateral release was performed by arthroscopy in 28 patients and in 21 patients in an open procedure. The mean follow-up time was 47.3 months. The rate of reluxation was 8 %. In the opinion of the patients, 44 (90 % of the follow-up) operations were evaluated as good/very good, the average Lysholm score was 87.3 ± 13.9. The clinical results were influenced by the point of time of the operation. Patients with monoluxation showed a lower rate of reluxation (3 % vs. 15 %) and superior functional and subjective results than those with recurrent dislocation. However, there were no significant differences between the open and closed performed lateral release. We recommend the technique presented here as a minimal-invasive method especially for patients with monoluxation of the patella.     

Der simultane distal gestielte Suralislappen

Exposed bradytrophic tissue in regions with high mechanical loading is an indication for defect coverage with (myo-, adipo-) fasciocutaneous flaps. In this case, distally based sural flaps were used for bilateral coverage of defects in weight-bearing areas of feet after fourth-degree frostbite. Residual defects can be covered with a split skin mesh graft. The definitive prosthetic supply of the foot assumes a stabilized plantar soft tissue situation. Among its advantages in comparison to free microvascular flaps, the locally based fasciocutaneous flap can be harvested with less donor site morbidity after elevation and does not require secondary debulking. It has been shown that the reduced stability at the border zone between flap and mesh graft has an adverse effect.     

Prospektive 1‑Jahres-Ergebnisse der arthroskopischen Arthrolyse des Ellenbogens

Background

Arthroscopic arthrolysis is a minimally invasive but technically demanding treatment option for elbow stiffness. Prospective clinical data are limited thus far.

Objectives

The aim was to analyze the clinical short-term results of arthroscopic elbow arthrolysis and to evaluate factors predictive of the outcome.

Materials and methods

28 patients (16 men, 12 women) following arthroscopic arthrolysis were enrolled in this study. The VAS (visual analogue scale) score, range of motion (ROM), and DASH score were obtained preoperatively as well as 6 weeks and 12 months after surgery. Posttraumatic elbow stiffness was present in 15 cases, elbow stiffness was due to primary osteoarthritis in 10 cases and due to other reasons in 3 cases. Osteoarthritis was absent in 1 case, grade 1 osteoarthritis was present in 7 cases, grade 2 in 9 cases and grade 3 in 11 cases according to the Broberg and Morrey classification.

Results

The VAS score was 5.3 ± 2.4 points preoperatively and decreased to 2.8 ± 2.7 points after 6 weeks and 1.6 ± 1.8 points after 12 months (p ≤ 0.001). The ROM increased from 86± 30° to 106± 28° after 6 weeks and to 121± 18° 12 months postoperatively (p ≤ 0.01). The DASH score improved from 39.3 ± 17.8 points to 23.8 ± 15.7 points after 6 weeks and to 11.3 ± 8.7 points 12 months postoperatively (p ≤ 0.001). Sex, age, grade of osteoarthritis and cause of elbow stiffness were not predictive of the clinical outcome. Complications were seen in 2 patients (7?%).

Conclusions

Arthroscopic arthrolysis represents an effective treatment method for elbow stiffness, which increases the range of motion, decreases pain levels and thus improves the functionality of the affected extremity regardless of sex, age, severity of osteoarthritis and etiology of elbow stiffness.

     

Computer-assisted navigation for the intraoperative assessment of lower limb alignment in high tibial osteotomy can avoid outliers compared with the conventional technique

Purpose

Longterm outcomes after valgization high tibial osteotomy (HTO) to treat varus osteoarthritis seem to depend mainly on correction precision. Intraoperative assessment of leg alignment based on radiological visualization of the mechanical axis is difficult and its precision is limited. A promising approach to improving precision is to make use of navigation systems. The case–control study reported here involved the evaluation of patients whose varus osteoarthritis had been treated by open-wedge high tibial ostoetomy, and an analysis of the effect of computer-guided navigation on postoperative leg alignment.

Methods

Forty patients with medial varus osteoarthritis managed by open-wedge high tibial osteotomy using a surgical navigation system were included in the present study (Group 1). They were compared with a retrospective control group (Group 2) of 40 patients with respect to postoperative leg alignment, correlation of planned and definitive correction, and postoperative deviation from the Fujisawa point.

Results

The mean values for planned and definitive correction showed no significant differences for identical demographic data. As a percentage of the width of the tibial plateau the postoperative weight-bearing radiographs showed a mechanical line that intersected with the knee base line at the desired value of 62 % (Fujisawa point) in 58.8 % (SD ± 6.1) in Group 1 and in 58.6 % (SD ± 8.1) in Group 2. Despite similar mean values a significantly higher number of corrections were outside the reference area (n = 7) in the non-navigated group, whereby all corrections were within the desired range in the navigated group. There were no significant differences in operation time.

Conclusions

This study showed that the use of a navigation system can not increase the precision of the open-wedge HTO procedure in patients with varus osteoarthritis but it can eliminate the outliers of a well defined range.

Level of evidence

Case-control study, Retrospective comparative study, Level III.     

Postprocedural microembolic events following carotid surgery and carotid angioplasty and stenting

OBJECTIVE: The relative safety of percutaneous carotid interventions remains controversial. Few studies have used diffusion-weighted magnetic resonance imaging (DW-MRI) to evaluate the safety of these interventions. We compared the incidence and distribution of cerebral microembolic events after carotid angioplasty and stenting (CAS) with distal protection to standard open carotid endarterectomy (CEA) using DW-MRI. METHODS: From November 2004 through August 2006, 69 carotid interventions (27 CAS, and 42 CEA) were performed in 68 males at a single institution. Pre- and postprocedure DW-MRI exams were obtained on each patient undergoing CAS and the 20 most recent CEA operations. These 46 patients (47 procedures as one patient underwent bilateral CEAs in a staged fashion) constitute our study sample, and the hospital records of these patients (27 CAS and 20 CEA) were retrospectively reviewed. The incidence and location of acute, postprocedural microemboli were determined using DW-MRIs and assessed independently by two neuroradiologists without knowledge of the subjects' specific procedure. RESULTS: Nineteen CAS patients (70%, 95% confidence interval [CI]: 42%-81%) demonstrated evidence of postoperative, acute, cerebral microemboli by DW-MRI vs none of the CEA patients (0%, 95% CI: 0%-17%) (P < .0001). Of the 19 CAS patients with postoperative emboli, nine (47%) were ipsilateral to the index carotid lesion, three (16%) contralateral, and seven (36%) bilateral. The median number of ipsilateral microemboli identified in the CAS group was 1 (interquartile ranges [IQR]: 0-2, range 0-21). The median number of contralateral microemboli identified in the CAS group was 0 (IQR: 0-1, range 0-5). Three (11%) CAS patients experienced temporary neurologic sequelae lasting less than 36 hours. These patients suffered 12 (six ipsilateral and six contralateral), 20 (19 ipsilateral and one contralateral), and zero microemboli, respectively. By univariate analysis, performing an arch angiogram prior to CAS was associated with a higher risk of microemboli (median microemboli 5 vs none, P =.04) CONCLUSIONS: Although our early experience suggests that CAS may be performed safely (no permanent neurologic deficits following 27 consecutive procedures), cerebral microembolic events occurred in over two-thirds of the procedures despite the uniform use of distal protection. Open carotid surgery in this series seems to offer a lower risk of periprocedural microembolic events detected by DW-MRI.     

Langzeitergebnisse nach operativer Versorgung von Pilon-tibial-Frakturen Eine retrospektive Untersuchung

Background: While Pilon fractures of the tibia have been treated for decades by primary open reduction and internal fixation by plate osteosynthesis, during the last 10 years differential treatment was developped: After primary open reduction nowadays patients are treated with (according to type of fracture and tissue damage). As well as primary open reduction and internal fixation a two-step treatment (primary external fixator and delayed ORIF) or consolidation by external fixator combined with minimal invasive osteosynthesis (cannulated screws and K-wires) has been implemented. Furthermore, the significance of primary bone grafting in comminuted fractures to prevent aseptic pseudarthrosis has been acknowledged. Methods: Of 151 patients with 160 pilon fractures treated from January 1979 to May 1995, 107 patients (113 fractures) were evaluated. Only the results of C2 and C3 fractures could be compared, as only in these groups were all three types of treatment used. Results: Over 75% of the treated fractures were closed fractures, most of them being fractures with a soft tissue damage grade 2 of the Oestern and Tscherne classification. In the open fractures we found mainly grade 3 fractures according to the Gustilo and Anderson classification. In 54.9% of all pilon tibial fractures we observed an uncomplicated course of healing. Early complications (25.7%) were mainly soft tissue infections, whereas we found pseudarthrosis to be the most frequent late complication. Highest infection rate (55.5%) was in the two-step treatment group (primary external fixator and delayed ORIF) and lowest in the primary internal stabilization group, although especially in the C2 and C3 fractures best clinical late results were obtained with the two-step procedure. Conclusion: The complication rate in the treatment of pilon fractures depends mainly on the type of fracture, the soft tissue damage and the type of treatment. The results of primary ORIF varied. In the case of low-grade soft tissue damage, good to excellent results were accomplished. In the case of higher-grade soft tissue damage, the problem of soft tissue coverage and reconstruction of the joint surface could be solved with good results by the two-step treatment. Herewith it is important to use limited open reduction of displaced fragments and fixation by cannulated screws and K-wires. We consider ORIF of the fibula necessary as stabilization of the second column of the ankle joint.