Chronic, acute and protocol-dependent effects of exercise on psycho-physiological health during long-term isolation and confinement

Exercise could prevent physical and psychological deteriorations, especially during pandemic times of lock-down scenarios and social isolation. But to meet both, the common exercise protocols require optimization based on holistic investigations and with respect to underlying processes. This study aimed to explore individual chronic and acute effects of continuous and interval running exercise on physical and cognitive performance, mood, and affect and underlying neurophysiological factors during a terrestrial simulated space mission. Six volunteers (three females) were isolated for 120 days. Accompanying exercise training consisted of a continuous and interval running protocol in a cross-over design. Incremental stage tests on a treadmill were done frequently to test physical performance. Actigraphy was used to monitor physical activity level. Cognitive performance, mood (MoodMeter^®), affect (PANAS), brain-derived neurotrophic factor (BDNF), insulin-like growth factor 1 (IGF-1), vascular-endothelial growth factor (VEGF), and saliva cortisol were investigated prior to, four times during, and after isolation, pre- and post-exercise on two separate days, respectively. As a chronic effect, physical performance increased (and IGF-1 tended) in the course of isolation and training until the end of isolation. Subjective mood and affect state, as well as cognitive performance, basal BDNF and VEGF levels, were well-preserved across the intervention. No acute effects of exercise were detected, besides slower reaction time after exercise in two out of nine cognitive tests, testing sensorimotor speed and memory of complex figures. Consistently higher basal IGF-1 concentrations and faster reaction time in the psychomotor vigilance test were found for the continuous compared to the interval running protocol. The results suggest that 120 days of isolation and confinement can be undergone without cognitive and mental deteriorations. Regular, individual aerobic running training supporting physical fitness is hypothesized to play an important role in this regard. Continuous running exercise seems to trigger higher IGF-1 levels and vigilance compared to interval running. Systematic and prolonged investigations and larger sample size are required to follow up on exercise-protocol specific differences in order to optimize the exercise intervention for long-term psycho-physiological health and well-being.

Influence of pedestal diameter on mode instabilities in Yb/Ce/Al-doped fibers

In this paper we present numerical and experimental results revealing that the mode instability threshold of highly Yb-doped, Ce/Al co-doped pedestal fibers is affected by the size of the index-increased pedestal structure surrounding the core. An alternative preparation technology for the realization of large mode area fibers with very large Al-doped silica pedestals is introduced. Three different pedestal fiber design iterations characterized by low photodarkening were manufactured and tested in counter-pumped amplifier setups. Up to 1.9 kW continuous-wave output power of near-diffraction-limited beam quality (M² = 1.26) was achieved with an 18/200/420 µm fiber of very low NA = 0.042, limited only by the occurrence of mode instabilities.

Application of open-path Fourier transform infrared spectroscopy for atmospheric monitoring of a CO2 back-production experiment at the Ketzin pilot site (Germany)

During a controlled "back-production experiment" in October 2014 at the Ketzin pilot site, formerly injected CO₂ was retrieved from the storage formation and directly released to the atmosphere via a vent-off stack. Open-path Fourier transform infrared (OP FTIR) spectrometers, on-site meteorological parameter acquisition systems, and distributed CO₂ point sensors monitored gas dispersion processes in the near-surface part of the atmospheric boundary layer. The test site provides a complex and challenging mosaic-like surface setting for atmospheric monitoring which can also be found at other storage sites. The main aims of the atmospheric monitoring of this experiment were (1) to quantify temporal and spatial variations in atmospheric CO₂ concentrations around the emitting vent-off stack and (2) to test if and how atmospheric monitoring can cope with typical environmental and operational challenges. A low environmental risk was encountered during the whole CO₂ back-production experiment. The study confirms that turbulent wind conditions favor atmospheric mixing processes and are responsible for rapid dilution of the released CO₂ leading to decreased detectability at all sensors. In contrast, calm and extremely stable wind conditions (especially occurring during the night) caused an accumulation of gases in the near-ground atmospheric layer with the highest amplitudes in measured gas concentration. As an important benefit of OP FTIR spectroscopic measurements and their ability to detect multiple gas species simultaneously, emission sources could be identified to a much higher certainty. Moreover, even simulation models using simplified assumptions help to find suitable monitoring network designs and support data analysis for certain wind conditions in such a complex environment.

Modulation of the CO2 fixation in dinickel azacryptands

Different linker molecules within the dinickel azacryptand moiety show strong influence towards their CO₂ coordination behaviour.

Bimetallic nickel complexes for selective CO2 carbon capture and sequestration

Herein we report on the selective CO₂ uptake from air by a dinickel azacryptand complex and its capability to act as a reversible CO₂ storage system.

Diabetic nephropathy but not HbA1c is predictive for frequent complications of Charcot feet - long-term follow-up of 164 consecutive patients with 195 acute Charcot feet

AIMS

To investigate the clinical characteristics, treatment and long-term outcome of patients with acute Charcot feet (CF).

METHODS

Single-center retrospective analysis. Treatment of CF: stage-dependent immobilization/weight-off therapy, orthopaedic/adjusted shoes, foot surgery. 164 consecutive participants (type 1 vs. type 2 diabetes): 12 vs. 150, non-diabetic peripheral neuropathy: n=2, presented with 195 (17 vs. 176) CF. Mean follow-up: 4.7 ± 2.5 (range 2.2-9.8) vs. 5.4 ± 2.9 (range 0.8-18.8) years, vital at follow-up: 100 vs. 88%.

RESULTS

Baseline characteristics: age: 43.7 ± 10.9 vs. 57.9 ± 8.9 years (p<0.001), male gender: 66.7 vs. 77.3%, diabetes duration: 19.2 ± 9.1 vs. 13 ± 8.6 years (p=0.018), GHb: 8.1 ± 2.4 vs. 7.6 ± 1.6%, BMI: 24 ± 5.3 vs. 33.7 ± 6.5 kg/m2 (p<0.001), Levine 1: 18.2 vs. 7.4%, Levine 2: 45.5 vs. 65.9%, Sanders 2: 58.3 vs. 68.5%, Sanders 3: 33.3 vs. 45%.

THERAPY

immobilization for 6 ± 4.2 vs. 5.4 ± 4.5 months, orthopaedic/adjusted shoes: 27.3 vs. 20.5%, foot surgery: 11.8 vs. 18.2%. Major complications: 50 vs. 56% (rocker bottom deformities: 23.5 vs. 46.3%, foot ulcerations: 17.6 vs. 24.6%, CF amputations: 0 vs. 6%), not CF amputations: 16.7 vs. 15.3%, second episodes of CF: 41.6 vs. 18.3% after 5-132 months. Diabetic nephropathy was associated with an increase, intensive antihypertensive therapy with a decrease of complications.

CONCLUSIONS

Patients with CF are middle-aged, overweight males with type 2 diabetes above 10 years. Patients with type 1 diabetes are younger, have normal BMI and longer diabetes duration. Major complications and second episodes of CF are frequent. Diabetic nephropathy could be a risk factor for CF related complications. The awareness for CF must be improved.The study was conducted due to the Declaration of Helsinki.

HAGIL (Hamburg Vigil Study): a randomized placebo-controlled double-blind study with modafinil for treatment of fatigue in patients with multiple sclerosis

Objective: To reassess the effect of modafinil, a wakefulness-promoting artificial psychostimulant, on fatigue and neuropsychological measures in patients with multiple sclerosis.

Methods: Multiple sclerosis (MS) patients with a baseline score of ≥4 on the Fatigue Severity Scale (FSS) and an Expanded Disability Status Scale score <7 were eligible for the 8-week randomized, double-blind, placebo-controlled study. Modafinil was dosed up to 200 mg/day within 1 week. Assessments were performed at baseline and after 4 and 8 weeks. The primary outcome parameter was the mean change of the FSS mean score. Secondary outcome variables were other questionnaires covering fatigue, daytime sleepiness and sleep quality. Cognitive impairment was assessed by the oral version of the Symbol Digit Modalities Test (SDMT) and the Paced Auditory Serial Addition Test (PASAT).

Results: The study included 121 MS patients. Dropout rate was 9%. Both treatment groups showed improvements through time. While mean FSS at 8 weeks showed a trend difference between groups in the intention-to-treat analysis, the primary endpoint was not met. Assessment of cognitive impairment by SDMT and PASAT showed contradictory results. All other secondary endpoints were not met. There was no major safety concern.

Conclusions: In general, the study does not support modafinil as an effective treatment for MS fatigue. However, the study shows the need for new study designs and endpoints in MS fatigue studies.

Intubating laryngeal mask as a ventilatory device during percutaneous dilatational tracheostomy: a descriptive study

BACKGROUND

We use an intubating laryngeal mask (ILM) in preference to an endotracheal tube (ETT) as the ventilatory device during percutaneous dilatational tracheostomy (PDT) to overcome potential problems such as difficult ventilation, accidental extubation, damage of the ETT or of the bronchoscope, and need for additional assistant to secure the airway. We report our experience with this method.

METHODS

In this prospective observational study, PDT was performed using the ILM in 86 patients. The insertion of the ILM, the quality of ventilation, and the view of the tracheal puncture site were rated as: 'very good', 'good', 'difficult', and 'not possible with ILM'.

RESULTS

The bronchoscope was not damaged during any case, and all PDTs were performed by two physicians, without the need for an additional assistant. PDTs with ILM were successful in 95% of the patients (n=82). The ratings were 'very good' or 'good' in 80% of cases with regards to ventilation, in 90% for identification of relevant structures and tracheal puncture site, and in 85% for the view inside the trachea during PDT. Tracheal re-intubation was required for inadequate ventilation with ILM in four patients.

CONCLUSIONS

The advantages of this procedure were lack of damage to the bronchoscope, the need for two instead of three persons to perform the PDT, and the excellent view inside the trachea. We recommend the ILM as a standard device for ventilation during bronchoscope-guided PDT.

Dynamic Cerebral Autoregulation in Patients with Ruptured and Unruptured Aneurysms after Induction of General Anesthesia

INTRODUCTION

Blood pressure management in patients undergoing surgery for clipping of aneurysms is demanding. More information about the ability of cerebral vessels to normally regulate cerebral blood flow may have a direct influence on the intraoperative management. In patients with subarachnoid hemorrhage (SAH) a disturbance of cerebral autoregulation has been reported and it correlated with the severity of the bleeding in these studies. The impairment of autoregulation was demonstrated using static measurements of cerebral pressure autoregulation. However, the dynamic component of the autoregulatory capacity seems to be of importance in the acute setting after SAH. The aim of this study was to evaluate dynamic pressure autoregulation in patients undergoing surgery for intracranial aneurysms.

PATIENTS/MATERIAL AND METHODS

36 patients with a mean age of 45 years were evaluated, 26 patients with acute SAH, 10 patients with unruptured aneurysms. Cerebral autoregulation in normocapnia was tested using thigh cuffs to alter arterial blood pressure and continuous registration of the blood flow velocities with transcranial Doppler sonography. After the induction of general anesthesia under normocapnia the autoregulatory index (ARI) was calculated (values between 0-9). Patient groups were compared using Wilcoxon- and Spearman's rank test.

RESULTS

The two patient groups were comparable with regard to gender, age, PaCO(2), blood flow velocities and blood pressure. In patients with SAH mean ARI was 3.1/3.3 (right/left side) compared to 4.7/4.6 (right/left side) in patients without SAH. The difference was statistically significant (Wilcoxon p = 0.0399). The degree of impairment of the autoregulatory capacity increased significantly (p = 0.006) with the severity of the SAH (Hunt&Hess and Fisher scale).

CONCLUSION

Dynamic pressure autoregulation is impaired in patients after SAH compared to patients without SAH and correlates with the severity of the SAH. We propose that autoregulation should be measured in all patients with SAH or that an impaired autoregulation should be taken into account in patients with SAH undergoing surgery in the acute phase.

Kortikale Reorganisation bei Kindern mit konnataler spastischer Hemiparese - eine funktionelle Magnetresonanztomographie-(fMRT-)Studie

PURPOSE

We applied fMRI to investigate atypical cortical activation in patients with connatal spastic hemiparesis using voluntary movements of the hand, foot, and tongue. The relation between the findings from fMRI and the motor dysfunction was examined.

MATERIALS AND METHODS

11 patients with connatal spastic hemiparesis were studied. Eight of these patients had periventricular leukomalacia (PVL), and three patients had cortical-subcortical lesions. To evaluate the severity of motor impairment tests for the upper and lower limb were performed. fMRI data were obtained in a block design using hand, foot, and tongue movements. As a control group, 14 healthy volunteers were examined with the fMRI protocol.

RESULTS

A laterally cortical representation of the paretic foot was found in three patients with PVL. In patients with cortical-subcortical lesions, tongue movements were associated with cortical activation restricted to the unaffected hemisphere. Movements of the paretic limb showed more ipsilateral activation in patients with PVL than in patients with cortical-subcortical lesions.

CONCLUSION

Different types of structural damage such as PVL and cortical-subcortical lesions show differences in fMRI examination.

Influence of intensified medical treatment and organ allocation on outcome of transplant candidates

BACKGROUND

To test how the organization of a pre-transplant clinic and changes in organ allocation modus influence the survival of potential transplant candidates, the survival of patients referred for transplant evaluation between 4/93 and 4/96 (group A) was compared to that of patients referred from 5/96 to 7/00(group B).

METHODS

After screening for transplant indication, group A was followed by the referring physician up to transplantation or 3-month reevaluation. Group B was closely followed by a specialized heart-failure clinic. Group A was transplanted according to Eurotransplant criteria, with waiting time being the strongest priority criterion. Due to an allocation partnership off our transplant centers, group B could be transplanted according to medical urgency regardless of waiting time.

RESULTS

Overall one-year survival after referral was 69.8% for group A vs. 91 %for group B (p <0.0001). Transplantation within 1 year was required in more group A than group B patients (34% vs. 23%)with worse one-year post-transplant survival in group A (82%vs. 93%).

CONCLUSIONS

Intensified treatment by a specialized heart failure program and an allocation system that allows for preferred transplantation of the 'sickest' patient improved over-all survival of transplant candidates and reduced the percentage of patients requiring transplantation.

[Postoperative pain therapy in minimally invasive direct coronary arterial bypass surgery. I.v. opioid patient-controlled analgesia versus intercostal block]

OBJECTIVE

Lately introduced cardiosurgical procedures such as MIDCAB enable an early extubation immediately after surgery. This also requires an adequate anesthesia regime and especially a sufficient postoperative analgesia. Patient controlled analgesia (PCA) and intercostal nerve blockade (ICB) were evaluated for their suitability for postoperative pain relief in patients undergoing a MIDCAB procedure.

MATERIAL AND METHODS

After approval by the local ethic committee and obtaining written informed consent 43 patients were included in this study. Anesthesia was induced and maintained in a total intravenous standardised manner with propofol, remifentanil, cisatracurium and additionally glyceroltrinitrate, clonidine and esmolol were given as needed. After revascularisation patients were randomly assigned to one of two groups receiving either 7.5 mg piritramid i.v. before extubation and continuing a PCA with 2 mg boli and a 10 min lockout, or an ICB with ropivacaine 1% (4 times 5 ml). Additionally all patients received 1 g paracetamol rectally before induction of anesthesia and 1 g metamizol i.v. at the end of surgery. A rescue medication of 3.75 mg piritramid i.v. was allowed. A pain score (NRS 0-10), the Aldrete score (AS 0-12) and oxygen saturation were obtained 1, 4, and 8 h after extubation.

RESULTS

The ICB group showed a significantly greater pain reduction in the first (5.8 +/- 1.8 vs. 7.3 +/- 1.9; P < 0.02) and fourth h (3.6 +/- 1.3 vs. 4.6 +/- 1.4; P < 0.02), respectively. Transfer to an intermediate care ward one hr after extubation was achieved more often in the ICB group according to the AS (ICB 9.6 +/- 1.5 vs. PCA 8.9 +/- 1.2; P < 0.05), too. There was no difference with respect to the oxygen saturation. The additional piritramid demand was 9.3 mg in the ICP group and 5 mg in the PCA group in the first 8 hours postoperative.

CONCLUSION

ICB gives a better pain relief in the early postoperative phase after MIDCAB procedures compared to a PCA. Both regimes are adequate in order to provide a sufficient pain relief and help to avoid prolonged postoperative mechanical ventilation. These will enable an early transfer of patients to an intermediate care station and save ICU capacity.

Severe obesity does not adversely affect perioperative mortality and morbidity in coronary artery bypass surgery

OBJECTIVE

Obese patients are usually thought to have an increased risk for complications in coronary artery bypass surgery.

METHODS

Therefore, the data of 500 consecutive patients undergoing coronary artery bypass grafting at our department in 1998 by use of cardiopulmonary bypass were analyzed. Severe obesity was defined as body mass index (BMI) > or = 30.0 kg/m(2). Obese patients (n=100; group O) were compared to the remaining 400 patients (group C). Both groups were comparable with respect to sex, history of prior myocardial infarction, chronic obstructive pulmonary disease, previous stroke, duration of cardiopulmonary bypass, aortic cross-clamp time and number of distal anastomoses performed. Obese patients were slightly younger and diabetes and hypertension were more common in these patients.

RESULTS

Survival and potential complications including perioperative myocardial infarction, sternal wound infection, wound infection at the leg, renal failure, stroke, prolonged mechanical ventilation, pneumonia, reexploration for bleeding, and atrial arrhythmias were analyzed. No significant differences between obese and non-obese patients were detected.

CONCLUSION

Severe obesity does not necessarily adversely affect perioperative mortality and morbidity in patients undergoing coronary artery bypass grafting in this study.

Topical amphotericin B application in severe bronchial aspergillosis after lung transplantation: report of experiences in 3 cases

Ulcerative tracheobronchial aspergillosis after lung transplantation (ltx) may lead to bronchial-pulmonary artery fistula that results in fatal bleeding. We report our early experience with combined systemic, aerolized and topical application of amphotericin B in 3 cases of bronchial aspergillosis after ltx. Two patients are still alive, but 1 died of bleeding from a fistula between the left upper lobe bronchus and the pulmonary artery. Aspergillosis in the second patient resolved with minimal stenosis of the left main and the left upper lobe bronchus, and the third patient developed an anastomotic stenosis that was successfully dilated.

Pericardiocentesis: differential aspects of a common procedure

OBJECTIVE

To evaluate the risk and effectiveness of pericardiocentesis in primary and repeat cardiac tamponade.

DESIGN

Retrospective analysis.

SETTING

Intensive care unit in a medical university hospital.

PATIENTS

Sixty-three consecutively admitted patients with cardiac tamponade.

INTERVENTIONS

In all patients pericardiocentesis was performed via the subxiphoid pathway after echocardiographic detection of the pericardial effusion.

MEASUREMENTS AND RESULTS

There was no adverse event in patients undergoing primary pericardiocentesis, which was sufficient to resolve pericardial effusion in 51 of 63 patients (81%). However, repeat pericardiocentesis necessitated by the recurrence of symptomatic pericardial effusion yielded suboptimal results in 10 of 12 patients (83%).

CONCLUSION

Pericardiocentesis is the treatment of choice for primary symptomatic pericardial effusion. In recurrent pericardial effusion surgical approaches appear to be preferable.

Development of obliterative bronchiolitis after allogeneic rat lung transplantation: implication of acute rejection and the time point of treatment

BACKGROUND

Chronic allograft failure represents the major cause of late morbidity and mortality after solid organ transplantation. Despite the pathological and clinical changes of this disease being well-described, the etiology and the causative factors are still under discussion. Several clinical, as well experimental studies, emphasize the significance of acute rejection. In rat model of left lung allo-transplantation (F344-to-WKY) the influence of acute rejection (AR) on the development of chronic rejection (CR) was studied.

METHODS

In Group I (n = 25) no immunosuppression was used, while methylprednisolone (MP) (10 mg/kg) was applied in Group II (n = 20) in the early phase of AR on postoperative Days 9, 10, 11 and in Group III (n = 20) during AR on Day 14, Day 15, Day 16. The rats were sacrificed on Day 5, Day 15/20, Day 30, Day 60, Day 100 and following HE-staining the extend of AR as well CR was graded according to the working formulation of The International Society of Heart and Lung Transplantation.

RESULTS

In Group I, AR was found at Day 15 and Day 30 which resolved spontaneously and resulted in CR on Day 60 and Day 100. In Group II, signs of AR were less evident on Day 20, while mild AR persisted on Day 30 and Day 60. On Day 100, normal lung structure was found in all rats. The recipients of Group III showed decreased signs of AR in the early course, however, severe CR was found on Day 60 and Day 100. Extensive airway inflammation with destruction of the subepithelial layer of the smaller airways resulted in severe early obliterative bronchiolitis.

CONCLUSIONS

Untreated severe AR in the early course after lung transplantation results in CR in the F344-to-WKY model. Preventive treatment with MP during the early phase of AR clearly diminishes the degree of AR and the graft recovers completely without any evidence of CR. Late application of steroids during the zenith of AR is successful to control the extent of AR, however, it fails to prevent CR.

Shoulder MRI after surgical treatment of instability

OBJECTIVE

To analyze magnetic resonance imaging (MRI) findings of the shoulder after an instability operation.

MATERIALS AND METHODS

Physical examinations, radiographs and MRI of 10 patients after anterior glenoid bone block insertion for ventral instability were compared. MRI included T1-weighted spin-echo (TR = 600, TE = 20 ms) and T2*-weighted gradient-echo sequences (TE = 600, TE = 18, Flip = 30 degrees) in the axial, oblique-coronal and oblique-sagittal planes.

RESULTS

No patient suffered from recurrent subluxation. We found fusion of the bone block with the anterior glenoid in seven cases, dislocation of the bone block without contact to the glenoid in one case, and no visible bone block in two cases. On MRI, the bone block showed either signal intensity equivalent to fatty bone marrow (n = 4) or was devoid of signal consistent with cortical bone or bone sclerosis (n = 4). In all patients, a low signal intensity mass, 2-4 cm in diameter, was visible next to the glenoid insertion site.

CONCLUSION

Insertion of a bone block onto the anterior glenoid induces formation of scar tissue, increasing the stability of the shoulder joint. This scar is well visible on MRI and forms independently of the behavior of the bone block itself. MRI is ideally suited for evaluating postoperative shoulder joints after bone-grafting procedures.

[The importance of the laryngeal mask in the difficult intubation and early experience with the intubating laryngeal mask airway--ILMA--Fastrach]

The conventional laryngeal mask airway ("Standard" laryngeal mask airway SLMA is of outstanding importance in the management of the difficult airway. The intubating laryngeal mask airway (ILMA, commercial name Fastrach) has become available recently. First results indicate that the excellent ventilation characteristics of SLMA are maintained, but in addition blind intubation is successful in more than 90% of patients with normal anatomy as well as with difficult intubation.

PURPOSE

We present the use of ILMA, compare the potential of the two laryngeal mask types in difficult intubation by own results, present the results of a first symposium on the ILMA held at Jersey in December 1996, the role of the SLMA in difficult intubation as proposed by the American and the French Societies of Anaesthesiology, as well as an outlook on possible uses of the ILMA in the light of the available results.

METHODS

The SLMA was prospectively used between 1992 and 1997 for 66 operations in 55 patients with difficult intubation (laryngoscopic view Cormack grade IV, n = 24; grade III, n = 35; grade < III, n = 7). 48 operations were performed after resection of a facial carcinoma, 14 on patients without carcinoma who could not be intubated conventionally, 5 on patients with periglottic pathology, and on 50 normals. The ILMA was used on 150 patients between 11/1996 and 11/1997, 106 had normal anatomy, 33 were difficult to intubate (Cormack grade IV, n = 12; grade III, n = 21), 24 had a reduced mouth opening of < or = 2.5 cm awake, 14 of these also were difficult to intubate.

RESULTS

Ventilation was superior to a face mask (FM): (SLMA: ventilation not sufficient (SaO2 < 90% > 30 sec) with a FM in 22 operations compared to 5 with a SLMA; ILMA: ventilation not sufficient with a FM in 7 operations compared to 3 with an ILMA). Blind intubation through a SLMA had a success rate of 50% and 34% in 50 normals and in 32 operations with difficult intubation after a mean of 2.6 intubation attempts each. The success rate per intubation attempt for the SLMA was 22% in normals and 13% in difficult intubation. Through an ILMA, blind intubation was successful in 92% of normals, 5 of them with immobile spine, in 91% in patients with difficult intubation, and in 83% in patients with reduced mouth opening. The success rate per intubation attempt was 60% in normals, 46% in difficult intubation, and 46% in reduced mouth opening, with a success rate for the first intubation attempt of 57%. This compares favourably with results presented at the Jersey symposium in 554 patients.

CONCLUSION

The ILMA maintains the superb ventilation potential of a SLMA in difficult intubation but doubles the success rate of blind intubation irrespective of anatomical difficulties, with a 50% success rate during the first intubation attempt. Possible uses of the ILMA may be in difficult intubation situations including immobile spine, in cannot ventilate--cannot intubate situations comparable to a SLMA with an improved chance of successful intubation, and perhaps as a device for ventilation and intubation for untrained people. The use of the ILMA can be trained during everyday practice. Expert assessment of successful endotracheal tube position is mandatory.

[Intubating laryngeal mask]

To improve the success of blind intubation through a laryngeal mask, Dr. A.I.J. Brain constructed the intubating laryngeal mask airway (ILMA), marketed under the name Fastrach. The new construction allows blind intubation with highly flexible endotracheal tubes up to 8 mm ID with cuff (straight Woodbridge type), securing the airway around the intubation process and maintaining most of the characteristics of a standard laryngeal mask airway (SLMA), including contraindications. An additional contraindication is the existence of a Zenker diverticle. Up to now, eight working groups reported a success rate of blind intubation through the ILMA of more than 90% in about 1,200 patients, with a success rate of blind intubation of more than 50% for the first intubation attempt. Ten percent of the patients were difficult to intubate with the same success rate for blind intubation as in normal patients. Reduced mouth opening does not seem to hinder the use of the ILMA in spite of its increased outer diameter of 2 cm, as long as it is possible to enlarge the mouth opening to > 2 cm during anaesthesia. The new ILMA more than doubles the success of blind intubation compared to an SLMA, irrespective of a large variety of intubation difficulties. Correct judgement of endotracheal tube position is mandatory. The ILMA has the potential to be used in patients who are difficult to intubate and to substitute the SLMA in "cannot ventilate--cannot intubate" situations. The future will show if the ILMA also will improve emergency airway management by inexperienced personnel, including intubation, as has been shown for the standard laryngeal mask airway in cardiopulmonary resuscitation for ventilation only.

[First experience with the laryngeal intubation mask]

OBJECTIVE

We report our initial experience with an improved model of the laryngeal mask airway, the intubating laryngeal mask airway (ILMA, commercial name Fastrach), which was designed by A.I.J. Brain to improve blind endotracheal intubation through a laryngeal mask.

METHODS

In the ILMA, a number of construction details were newly designed compared to a standard laryngeal mask airway (SLM): 1) the angle between the shaft and the mask plane is changed, and also the radius of the shaft, 2) the internal diameter of the shaft is increased to allow the passage of an 8.0 mm cuffed endotracheal tube, resulting in an outer diameter of 2.0 cm, 3) a stable rubber lip (epiglottic elevating bar) is incorporated instead of the gills to clear the epiglottis out of the lumen during the passage of the endotracheal tube, 4) the shaft is manufactured out of stainless steel covered by silicone with a handle attached for more precise guidance. We prospectively used the ILMA in 80 patients for blind intubation. 51 had normal anatomy (group I), 19 were difficult to intubate (Cormack grade 3-4; group II), 18 had a reduced mouth opening (< or = 2.5 cm awake; group III), 8 of them also were difficult to intubate.

RESULTS

Insertion of the ILMA and ventilation was possible in all patients but one with a mouth opening of 1.3 cm during anaesthesia. 4 patients with difficult intubation and one with normal anatomy could not be ventilated with a face mask but could be ventilated with the ILMA. Blind intubation was successful in 69 out of 80 patients (global success rate 87%; group I: 84%; II: 95%; III: 83%), in 38 during the first attempt (initial success rate 48%; group I: 45%; II: 63%; III: 44%), showing no difference for patients with normal anatomy, difficult intubation or reduced mouth opening. For 82 successful intubations, 157 intubation attempts were performed (success rate per attempt 52%; group I: 48%; II: 67%; III: 54%). Success rate per attempt decreased to 42%, if intubation was not successful during the first attempt (106 intubation attempts resulting in 44 successful intubations, including 31 intubation attempts for 11 failures; group I: 35%; II: 56%; III: 38%). Intubation through the ILMA was not possible in 11 patients (14%). Failures to intubate were caused by a reduced mouth opening in 1 patient, an unsuited endotracheal tube in 1 patient, a wrong size of the ILMA may have been the cause in 6 patients, in the remaining 3, lacking personal skill may have been responsible. Endotracheal tubes suited to be used with the ILMA are straight or preformed Woodbridge tubes, whereas standard plastic tubes are too stiff. Manouvres facilitating blind intubation though the ILMA were careful alignment of the ILMA with the handle, an up and down manouvre, rotation of the tube or head movements.

CONCLUSION

The ILMA improved ventilation compared to a face mask and almost doubled the success rate of blind intubation compared to a SLM in our hands in a variety of intubation situations. The ILMA has the potential to be useful in difficult to intubate patients--except those with cervical pathology--or in emergency medicine. Handling can be trained during every day routine. Experienced judgement of definite endotracheal tube placement is mandatory.

Gene transfer into rat heart-derived endothelial cells

OBJECTIVE

Progressive graft arteriosclerosis is responsible for the majority of late deaths in cardiac transplant recipients. Despite many investigations, the pathogenesis of this disease remains undetermined and its control inadequate. A somatic gene transfer during the cold ischemic time and thus before transplantation might be a new therapeutic tool. This approach allows a long incubation time of the DNA and a safe transfer with liposomes and transferrin with less adverse effects for the organ recipient.

METHODS

The target cells (microvascular endothelial cells (MVECs)) for this gene transfer were isolated from rat hearts by perfusion with collagenase via an aortic cannulae. The cells were purified by changing the medium 30 min after subcultivation in order to remove fibroblasts and smooth muscle cells. The endothelial cells (ECs) were identified by typical morphology and the uptake of Dil-Ac-LDL. The gene transfer was carried out with a beta-galactosidase reporter plasmid (pCMVbeta), cationic liposomes (Lipofectin), and transferrin. Different transfection solutions were prepared with or without serum, and with different plasmid-liposome ratios and transferrin concentrations. The transfer rate was monitored with a semiquantitative orthonitrophenyl-beta/-D-galactoside (ONPG) assay and histologically by X-Gal staining. The cytotoxicity of this procedure was determined with a colorimetric ELISA with Alamar blue. The cardioplegic property of the transfection solution was tested in a Langendorff perfusion system monitoring the coronary blood flow over time after a cold ischemic time of 4 h.

RESULTS

The maximal gene expression could be detected after transfection with 4 microl Lipofectin, 2 microg pCMVbeta, and 16 microg transferrin/200 microl transfection solution. Under these conditions 60% of the cells showed a blue staining with X-Gal. Only 20% of the cells died during transfection. The lowest cytotoxicity during cold ischemic time for ECs was assessed with normal cell culture medium and the Buckberg solution. The best coronary flow rates after 4 h cold ischemia of the heart were measured for cardioplegia with St. Thomas and Buckberg solutions. In summary, the best transfection solution with a good cardioplegic property was the Buckberg solution.

CONCLUSIONS

Finally, the results of this study show that an effective DNA delivery with a low toxicity into ECs is possible with a combination of liposomes and transferrin. This method might be useful for a safe and effective gene transfer into solid organs during the cold ischemic time and thus a therapeutic tool for chronic rejection.

[Safe handling of the laryngeal mask airway in eye surgery]

BACKGROUND

We prospectively used the laryngeal mask airway (LM) in eye surgery to evaluate: 1) the limits of safe handling; 2) the feasibility of its use in long operative procedures, and 3) whether patients with higher anaesthetic risk (hypertension, asthma, children) may profit from the LM.

METHODS

In 792 patients leak pressure, cuff volume, duration of anaesthesia, and complications were noted; 33 were children under 10 years of age, 100 had hypertension or severe asthma. In 54 patients cuff volume was increased to measure its influence on leak pressure; in 241 leak pressure was also measured at the end of the procedure; in 31 cuff pressure was measured under standard conditions over time; in 7 dead space was evaluated with the BANALYZER program; and in 300 blind endotracheal suction was attempted through the LM.

RESULTS

Limits for the safe use of the LM were a leak pressure < 12 cm H2O combined with insufficient spontaneous ventilation (CO2et > 7 vol.%; n = 14), dislocation with gastric inflation (n = 2), and bronchial secretions (n = 1), as blind suctioning of the trachea through the LM was possible in only 1 out of 300 attempts. These limits could be recognised before the start of the operation in most cases. Laryngospasm or closure of the glottis (n = 36, 4.5%) was treatable and did not necessitate abandoning the use of the LM. Mean leak pressure was 17.7 +/- 4.8 cm H2O, showing a comparable distribution in adults and in children and being improved mainly by position changes of the LM, but not by changes in cuff volume. No gas leak occurred when the individual peak inspiratory pressure was equal to or lower than the measured leak pressure except in children. Dead space was almost halved by the LM compared to a face mask (90 +/- 13 vs. 162 +/- 31 ml; P < 0.05), allowing spontaneous breathing to be adequate even when manual assistance of ventilation was not possible (n = 14, 1.8%). In patients with sufficiently high leak pressures, the LM was safely used for long operations (up to 240 min), as leak pressure did not change over time. When only a low leak pressure could be achieved, deep breaths could be delivered by prolongation of the inspiratory time, thereby preventing atelectasis if tidal volume was limited. Cuff pressure rose to about 100 cm H2O within 60 min and should be monitored. In children, air was aspirated intermittently out of the stomach in procedures longer than 30 min; in adults, we monitored and buffered gastric contents where necessary. In patients at risk, the LM stimulates the circulation and bronchial reactivity less than an endotracheal tube. Children could be discharged earlier from the recovery room (0.45-1.5 h vs. > or = 2 h after neuromuscular relaxation and intubation).

CONCLUSION

Limits for the use of the LM in eye surgery are delineated. Within these limits, the LM offers control over the airway comparable to that of an endotracheal tube with less stimulation. The LM has to be applied by an experienced user, and has advantages in eye surgery.

Inverse control of growth hormone and prolactin secretion in clonidine-stimulated dairy cattle

Clonidine is a specific alpha-2-adrenoreceptor agonist that stimulates growth hormone (GH) release in animals and humans. This drug was used to study the GH and prolactin (PRL) secretory response in dairy cows and heifers. An i.v. infusion of 10 micrograms/kg body weight induced GH release to a peak concentration after 30-60 min, while 2 micrograms/kg had no effect on GH secretory patterns. Plasma PRL decreased significantly (P < 0.01) starting 15-60 min after both doses of clonidine, this effect lasting up to 6 h. Clonidine significantly lowered plasma insulin (P < 0.01) and raised plasma glucose (P < 0.01). The changes in plasma GH, PRL, insulin and glucose differed significantly between doses, the 10 micrograms/kg dose being more effective (P < 0.01). The results of our investigation in dairy cattle provide evidence of (i) an increase in GH release after 10 micrograms/kg clonidine; (ii) a concomitant decrease in PRL secretion, hence GH and PRL secretion in cattle appear inversely controlled; (iii) a significant difference between the effects of the 2 and 10 micrograms/kg doses and (iv) no relationship between the changes in plasma GH and PRL after clonidine and plasma hormone levels before treatment.