Evaluation of a novel cricothyroidotomy introducer in a simulated obese porcine model: a randomised crossover comparison with scalpel cricothyroidotomy.

The Difficult Airway Society 2015 guidelines for management of unanticipated difficulties in tracheal intubation in adults have generated much discussion regarding Plan D: emergency front-of-neck access with a scalpel-bougie cricothyroidotomy technique. There is concern that this technique may not provide an adequate pathway for the bougie and subsequently the tracheal tube, especially in obese patients with deeper airway structures. This could lead to the formation of a false passage, trauma and failure. A novel cricothyroidotomy introducer, 8 mm wide and 170 mm long, with a sharp leading edge and guiding channel to pass a bougie into the trachea, has been designed to complement the scalpel cricothyroidotomy technique. A comparison study of the use of this novel introducer with the scalpel technique in a simulated obese porcine laryngeal model demonstrated shorter insertion times (median (IQR [range]) 85 (65-123 [48-224]) s vs. 84 (72-184 [46-377]) s, p = 0.030). All 26 (100%) participants successfully performed cricothyroidotomy in the introducer group, whereas only 24 (92%) participants were successful in the scalpel group. The introducer group required fewer attempts to access the trachea compared with the scalpel group (p = 0.046). False passages occurred eight (31%) times in the introducer group compared with 17 (65%) times in the scalpel group (p = 0.022). There were no statistical differences in tracheal trauma (p = 0.490), ease of use (p = 0.220) and device preference (p = 0.240). This novel cricothyroidotomy introducer has shown promising results in securing the airway in an emergency front-of-neck access situation. With robust training, this introducer could potentially be complementary to the scalpel-bougie cricothyroidotomy technique.

Comparison of analgesic efficacy of four-quadrant transversus abdominis plane (TAP) block and continuous posterior TAP analgesia with epidural analgesia in patients undergoing laparoscopic colorectal surgery: an open-label, randomised, non-inferiority trial.

Posterior transversus abdominis plane blocks have been reported to be an effective method of providing analgesia after lower abdominal surgery. We compared the efficacy of a novel technique of providing continuous transversus abdominis plane analgesia with epidural analgesia in patients on an enhanced recovery programme following laparoscopic colorectal surgery. A non-inferiority comparison was used. Adult patients undergoing elective laparoscopic colorectal surgery were randomly assigned to receive continuous transversus abdominis plane analgesia (n = 35) vs epidural analgesia (n = 35), in addition to a postoperative analgesic regimen comprising regular paracetamol, regular diclofenac and tramadol as required. Sixty-one patients completed the study. The transversus group received four-quadrant transversus abdominis plane blocks and bilateral posterior transversus abdominis plane catheters that were infused with levobupivacaine 0.25% for 48 h. The epidural group received an infusion of bupivacaine and fentanyl. The primary outcome measure was visual analogue scale pain score on coughing at 24 h after surgery. We found no significant difference in median (IQR [range]) visual analogue scores during coughing at 24 h between the transversus group 2.5 (1.0-3.0 [0-5.5]) and the epidural group 2.5 (1.0-5.0 [0-6.0]). The one-sided 97.5% CI was a 0.0 (∞-1.0) difference in means, establishing non-inferiority. There were no significant differences between the groups for tramadol consumption. Success rate was 28/30 (93%) in the transversus group vs 27/31 (87%) in the epidural group. Continuous transversus abdominis plane infusion was non-inferior to epidural infusion in providing analgesia after laparoscopic colorectal surgery.

Inhalational induction of general anaesthesia for elective caesarean: ethical acceptability in treatment-resistant needle phobia?

We describe the anaesthetic management of a parturient who, due to a severe needle phobia, requested an inhalational induction of general anaesthesia for an elective caesarean section. If general anaesthesia is indicated, conventional practice in the UK is to perform a rapid sequence induction via an intravenous route of drug administration to allow rapid intubation of the trachea. This is because obstetric patients are considered to have a 'full stomach' due to the effects of pregnancy and labour on gastric emptying, and a higher risk of aspiration with consequent maternal and fetal adverse outcomes. Despite a thorough consent process highlighting these significant risks, the patient insisted on an inhalational induction of anaesthesia. We present the case and discuss the ethical dilemma (relating to patient care) in situations in which decisions made by patients deviate from medical recommendations.

A wearable, EEG-based massage headband for anxiety alleviation.

In this work, we would like to discuss our findings obtained from the newly proposed hardware design for anxiety detection and its mitigation where a subject's state of mind is identified from the neurological data retrieved. A feedback-based network implemented for stress alleviation mainly comprises of a pair of massage motors and RGB light-emitting diode (LED) that activate during conditions of stress detected, a custom-made Electroencephalography (EEG)-sensor and a massage motor circuit both functioning on an Arduino driven platform. The skin electrodes facilitate a hassle-free retrieval of beta waves from the frontal areas that are transmitted wirelessly by a Bluetooth console to a computer post signal amplification and filtration. Rising amplitudes of beta signals that are associated to anxiety have been successfully tackled in three out of four subjects by suppressing the high values due to the massage motor therapy introduced. The motors on sensing high amplitude values exceeding the pre-set threshold limits during the three experiment trials rotate smoothly thus helping one to relax and guaranteeing a higher work performance.

Comparison of mean frequency and median frequency in evaluating muscle fiber type selection in varying gait speed across healthy young adult individuals.

The preferential slow and fast twitches fiber involvement in varying gait speed has not been thoroughly investigated. Attempt to classify fiber type in changing speed should be closely investigated and scrutinized as the histochemical-related experiments are cumbersome and time consuming. In addressing this issue, electromyography (EMG) is utilized to extract the muscle fiber type features by altering the muscle fatigue indices, namely mean frequency (MNF) and median frequency (MDF). Recently, there are no universal indices to determine the muscle type. In this paper, the MNF and MDF are employed in discovering the muscle type variation as the speed changes. Besides drawing the potential of MNF and MDF in unveiling the muscle type, both the parameters are applied to investigate the muscles that are recruited and which muscle type are involved as the gait velocity changes. In this study, six healthy and young participants are recruited, whereby the EMG sensors are placed on twelve lower extremity muscles. The EMG signals are then processed via Matlab software to deduce MNF and MDF. The MNF and MDF are determined from every of the phase gait, namely stance and swing. From the results obtained, it reveals that the superiority of the MNF over the MDF in determining and interpreting the muscle recruitment in both gait phases as the speed increases. The MNF, moreover, is able to show an apparent difference in muscle type selection compared to MDF. Interestingly, it is discovered that as the speed increases from slow to fast, the MNF decreases, which indicates that more muscle fiber type I is recruited. Contrarily, the MNF increases as the speed intensity decreases, which indicates that the distribution of muscle type II is prominent.

Fibreoptic bronchoscopy in the diagnosis of pulmonary tuberculosis--a Malaysian experience.

We report our experience on the use of fibreoptic bronchoscopy in the diagnosis of pulmonary tuberculosis. The case records of 1,274 patients who underwent fibreoptic bronchoscopy at the National Tuberculosis Centre, Kuala Lumpur, Malaysia during a three-year period were reviewed. In 120 of them the final diagnosis was tuberculosis. Bronchoscopy confirmed the diagnosis in 37 patients (30.8%). This was achieved by bronchial aspiration for culture in 26 patients (70.3%) and bronchial biopsy for histopathology in 11 patients (29.7%). It was the exclusive method of confirmation in 16 patients (13.3%). Sputum culture was positive in 62 patients (51.7%) including 41 patients (34.2%) in whom bronchoscopy was unhelpful. Six patients had diagnosis confirmed by other means while in 36 others (30%) it was based on clinical features and supportive basic investigations. There were no complications noted. We conclude that while sputum examination remains the mainstay for diagnosing pulmonary tuberculosis, fibreoptic bronchoscopy serves as a safe and useful adjunct.

Interlocking nails for treatment of femoral fractures.

A series of 23 fractures of the femur were treated using femoral interlocking nails. The average follow-up period was 14.8 months. There were 14 closed fractures and 9 compound fractures. Closed nailing was done for 8 patients and open nailing for 15 patients. All the fractures united. There were no superficial or deep infections. The most common complication was leg length discrepancy; shortening occurred in 5 patients whereas lengthening occurred in 2 patients. It is a technically demanding procedure but it is the method of choice in our Institution for stabilising complex fractures of the femoral shaft.

Knee arthrodesis with interlocking nail after excision of giant cell tumour of the distal femur.

Giant cell tumour of bone occurring around the knee is fairly common and can be difficult to manage. We report a case of such tumour involving the distal femur which was successfully treated with complete excision followed by arthrodesis of the knee with a long interlocking intramedullary nail.

Hamstrings and quadriceps muscle contributions to energy generation and dissipation at the knee joint during stance, swing and flight phases of level running.

BACKGROUND: Human movements involve the generation and dissipation of mechanical energy at the lower extremity joints. However, it is unclear how the individual knee muscles contribute to the energetics during running. OBJECTIVE: This study aimed to determine how each hamstring and quadricep muscle generates and dissipates energy during stance, swing and flight phases of running. METHODS: A three-dimensional lower extremity musculoskeletal model was used to estimate the energetics of the individual hamstrings (semimembranosus, semitendinosus, biceps femoris long and short-heads) and quadriceps (rectus femoris, vastus medialis, vastus intermedius and vastus lateralis) muscles for a male subject during level running on a treadmill at a speed of 3.96 m/s. RESULTS: Our findings demonstrated that the knee flexors generated energy during stance phase and dissipated energy during swing phase, while the knee extensors dissipated energy during the flexion mode of both stance and swing phases, and generated energy during the extension mode. During flight phase, the knee flexors generated energy during the flight phase transiting from toe-off to swing, while the knee extensors generated energy during the flight phase transiting from swing to heel-strike. CONCLUSION: Individual knee flexors and extensors in the hamstrings and quadriceps play important roles in knee joint energetics, which are necessary for proper execution and stabilization of the stance, swing and flight phases of running.

Shod landing provides enhanced energy dissipation at the knee joint relative to barefoot landing from different heights.

Athletic shoes can directly provide shock absorption at the foot due to its cushioning properties, however it remains unclear how these shoes may affect the level of energy dissipation contributed by the knee joint. This study sought to investigate biomechanical differences, in terms of knee kinematics, kinetics and energetics, between barefoot and shod landing from different heights. Twelve healthy male recreational athletes were recruited and instructed to perform double-leg landing from 0.3-m and 0.6-m heights in barefoot and shod conditions. The shoe model tested was Brooks Maximus II. Markers were placed on the subjects based on the Plug-in Gait Marker Set. Force-plates and motion-capture system were used to capture ground reaction force (GRF) and kinematics data respectively. 2×2-ANOVA (barefoot/shod condition×landing height) was performed to examine differences in knee kinematics, kinetics and energetics between barefoot and shod conditions from different landing heights. Peak GRF was not significantly different (p=0.732-0.824) between barefoot and shod conditions for both landing heights. Knee range-of-motion, flexion angular velocity, external knee flexion moment, and joint power and work were higher during shod landing (p<0.001 to p=0.007), compared to barefoot landing for both landing heights. No significant interactions (p=0.073-0.933) were found between landing height and barefoot/shod condition for the tested parameters. While the increase in landing height can elevate knee energetics independent of barefoot/shod conditions, we have also shown that the shod condition was able to augment the level of energy dissipation contributed by the knee joint, via the knee extensors, regardless of the tested landing heights.

Non-linear flexion relationships of the knee with the hip and ankle, and their relative postures during landing.

The knee joint, together with the hip and ankle, contributes to overall shock absorption through their respective flexion motions during landing. This study sought to investigate the presence of a lower extremity coordination pattern by determining mathematical relationships that associate knee flexion angles with hip flexion and ankle dorsiflexion angles during landing phase, and to determine relative postures of the hip and ankle, with reference to the knee, and examine how these relative postures change during key events of the landing phase. Eight healthy male subjects were recruited to perform double-leg landing from 0.6-m height. Motion capture system and force-plates were used to obtain kinematics and ground reaction forces (GRF) respectively. Non-linear regression analysis was employed to determine appropriate mathematical relationships of the hip flexion and ankle dorsiflexion angles with knee flexion angles during the landing phase. Relative lower extremity postures were compared between events of initial contact, peak GRF and maximum knee flexion, using ANOVA on ranks. Our results demonstrated a lower extremity coordination pattern, whereby the knee flexion angles had strong exponential (R(2) = 0.92-0.99, p < 0.001) and natural logarithmic (R(2) = 0.85-0.97, p < 0.001) relationships with hip flexion and ankle dorsiflexion angles respectively during the landing phase. Furthermore, we found that the s ubjects adopted distinctly different relative lower extremity postures (p < 0.05) during peak GRF as compared to initial contact. These relative postures were further maintained till the end of the landing phase. The occurrence of these relative postures may be a reflexive mechanism for the subjects to efficiently absorb the impact imposed by the peak GRF.

Sagittal knee joint kinematics and energetics in response to different landing heights and techniques.

Single-leg and double-leg landing techniques are common athletic maneuvers typically performed from various landing heights during intensive sports activities. However, it is still unclear how the knee joint responds in terms of kinematics and energetics to the combined effects of different landing heights and techniques. We hypothesized that the knee displays greater flexion angles and angular velocities, joint power and work in response to the larger peak ground reaction force from 0.6-m height, compared to 0.3-m height. We further hypothesized that the knee exhibits elevated flexion angles and angular velocities, joint power and work during double-leg landing, relative to single-leg landing. Ground reaction force, knee joint kinematics and energetics data were obtained from 10 subjects performing single-leg and double-leg landing from 0.3-m to 0.6-m heights, using motion-capture system and force-plates. Higher peak ground reaction force (p<0.05) was observed during single-leg landing and/or at greater landing height. We found greater knee flexion angles and angular velocities (p<0.05) during double-leg landing and/or at greater landing height. Elevated knee joint power and work were noted (p<0.05) during double-leg landing and/or at greater landing height. The knee joint is able to respond more effectively in terms of kinematics and energetics to a larger landing impact from an elevated height during double-leg landing, compared to single-leg landing. This allows better shock absorption and thus minimizes the risk of sustaining lower extremity injuries.

Direct contribution of axial impact compressive load to anterior tibial load during simulated ski landing impact.

Anterior tibial loading is a major factor involved in the anterior cruciate ligament (ACL) injury mechanism during ski impact landing. We sought to investigate the direct contribution of axial impact compressive load to anterior tibial load during simulated ski landing impact of intact knee joints without quadriceps activation. Twelve porcine knee specimens were procured. Four specimens were used as non-impact control while the remaining eight were mounted onto a material-testing system at 70 degrees flexion and subjected to simulated landing impact, which was successively repeated with incremental actuator displacement. Four specimens from the impacted group underwent pre-impact MRI for tibial plateau angle measurements while the other four were subjected to histology and microCT for cartilage morphology and volume assessment. The tibial plateau angles ranged from 29.4 to 38.8 degrees . There was a moderate linear relationship (Y=0.16X; R(2)=0.64; p<0.001) between peak axial impact compressive load (Y) and peak anterior tibial load (X). The anterior and posterior regions in the impacted group sustained surface cartilage fraying, superficial clefts and tidemark disruption, compared to the control group. MicroCT scans displayed visible cartilage deformation for both anterior and posterior regions in the impacted group. Due to the tibial plateau angle, increased axial impact compressive load can directly elevate anterior tibial load and hence contribute to ACL failure during simulated landing impact. Axial impact compressive load resulted in shear cartilage damage along anterior-posterior tibial plateau regions, due to its contribution to anterior tibial loading. This mechanism plays an important role in elevating ACL stress and cartilage deformation during impact landing.

Extent and distribution of tibial osteochondral disruption during simulated landing impact with axial tibial rotation restraint.

Post-traumatic knee osteochondral injuries are often coupled with anterior cruciate ligament (ACL) injury mechanisms during landing. However, it is not well understood whether restraining axial tibial rotation during landing would influence the extent and distribution of osteochondral disruption. Using ski landing as an example, this study subjected knee specimens to simulated landing impact without and with axial tibial rotation restraint, and investigated the extent and distribution of osteochondral disruption at the tibial plateau. Twenty-one porcine knee specimens were randomly divided into three test conditions, namely: (1) control, (2) impact only (I), and 3) impact with restraint (IR). Simulated landing impact was applied to the specimens based on a single 10 Hz haversine. Osteochondral explants were obtained from anterior, middle and posterior regions of medial and lateral tibial compartments. The extent of cartilage and trabecular disruption in these explants was examined based on histology, SEM and microCT. Only specimens in unrestrained condition incurred ACL failure upon impact. Restraining axial tibial rotation during simulated impact generally inflicted cartilage damage and deformation, and further caused trabecular disruption. Axial tibial rotation restraint did not necessarily restrict anterior tibial translation, as indicated by the presence of relative posterior femoral translation and osteochondral disruption at anterior-posterior tibial regions. While the results obtained in the current study may not be completely translatable to human models, there is likelihood that restraining axial tibial rotation during landing may help to prevent ACL failure, but will also induce osteochondral disruption in most tibial regions.

Effect of an anterior-sloped brace joint on anterior tibial translation and axial tibial rotation: a motion analysis study.

BACKGROUND: Anterior tibial translation and axial tibial rotation are major biomechanical factors involved in anterior cruciate ligament injuries. This study sought to evaluate a brace prototype designed with an anterior-sloped joint, in terms of its efficacy in attenuating anterior tibial translation and axial tibial rotation during landing, using a motion analysis approach. METHODS: Ten healthy male subjects performed single-leg landing tasks from a 0.6-m height with and without the brace prototype. Ground reaction force and kinematics data were obtained using a motion-capture system and force-plates. Anterior tibial translation and axial tibial rotation were determined based on tibial and femoral marker reference frames. Vertical and anterior-posterior ground reaction forces, hip, knee and ankle joint range-of-motions and angular velocities, anterior tibial translation and axial tibial rotation were compared between unbraced and braced conditions using Wilcoxon signed-rank test. FINDINGS: We found no significant difference in peak vertical and anterior-posterior ground reaction forces (p=0.770 and p=0.332 respectively) between unbraced and braced conditions. Knee joint range-of-motion and angular velocity were lower (p=0.037 and p=0.038 respectively) for braced condition than unbraced condition. Anterior tibial translation and axial tibial rotation were reduced (p=0.027 and p=0.006 respectively) in braced condition, compared to unbraced condition. INTERPRETATION: The anterior-sloped brace joint helps to attenuate anterior tibial translation and axial tibial rotation present in the knee joint during landing. It is necessary to test the brace prototype in a sporting population with realistic sports landing situations in order to assess its effectiveness in lowering anterior cruciate ligament injury risk.

Effect of landing height on frontal plane kinematics, kinetics and energy dissipation at lower extremity joints.

Lack of the necessary magnitude of energy dissipation by lower extremity joint muscles may be implicated in elevated impact stresses present during landing from greater heights. These increased stresses are experienced by supporting tissues like cartilage, ligaments and bones, thus aggravating injury risk. This study sought to investigate frontal plane kinematics, kinetics and energetics of lower extremity joints during landing from different heights. Eighteen male recreational athletes were instructed to perform drop-landing tasks from 0.3- to 0.6-m heights. Force plates and motion-capture system were used to capture ground reaction force and kinematics data, respectively. Joint moment was calculated using inverse dynamics. Joint power was computed as a product of joint moment and angular velocity. Work was defined as joint power integrated over time. Hip and knee joints delivered significantly greater joint power and eccentric work (p<0.05) than the ankle joint at both landing heights. Substantial increase (p<0.05) in eccentric work was noted at the hip joint in response to increasing landing height. Knee and hip joints acted as key contributors to total energy dissipation in the frontal plane with increase in peak ground reaction force (GRF). The hip joint was the top contributor to energy absorption, which indicated a hip-dominant strategy in the frontal plane in response to peak GRF during landing. Future studies should investigate joint motions that can maximize energy dissipation or reduce the need for energy dissipation in the frontal plane at the various joints, and to evaluate their effects on the attenuation of lower extremity injury risk during landing.

Regression relationships of landing height with ground reaction forces, knee flexion angles, angular velocities and joint powers during double-leg landing.

Ground reaction forces (GRF), knee flexion angles, angular velocities and joint powers are unknown at large landing heights, which are infeasible for laboratory testing. However, this information is important for understanding lower extremity injury mechanisms. We sought to determine regression relationships of landing height with these parameters during landing so as to facilitate estimation of these parameters at large landing heights. Five healthy male subjects performed landing tasks from heights of 0.15-1.05 m onto a force-plate. Motion capture system was used to obtain knee flexion angles during landing via passive markers placed on the lower body. An iterative regression model, involving simple linear/exponential/natural logarithmic functions, was used to fit regression equations to experimental data. Peak GRF followed an exponential regression relationship (R(2)=0.90-0.99, p<0.001; power=0.987-0.998). Peak GRF slope and impulse also had an exponential relationship (R(2)=0.90-0.96, p<0.001; power=0.980-0.997 and R(2)=0.90-0.99, p<0.001; power=0.990-1.000 respectively) with landing height. Knee flexion angle at initial contact and at peak GRF had an inverse-exponential regression relationship (R(2)=0.81-0.99, p<0.001-p=0.006; power=0.834-0.978 and R(2)=0.84-0.97, p<0.001-p=0.004; power=0.873-0.999 respectively). There was also an inverse-exponential relationship between peak knee flexion angular velocity and landing height (R(2)=0.86-0.96, p<0.001; power=0.935-0.994). Peak knee joint power demonstrated a substantial linear relationship (R(2)=0.98-1.00, p<0.001; power=0.990-1.000). The parameters analyzed in this study are highly dependent on landing height. The exponential increase in peak GRF parameters and the relatively slower increase in knee flexion angles, angular velocities and joint power may synergistically lead to an exacerbated lower extremity injury risk at large landing heights.