Human Error Probability Assessment During Maintenance Activities of Marine Systems

BACKGROUND: Maintenance operations on-board ships are highly demanding. Maintenance operations are intensive activities requiring high manemachine interactions in challenging and evolving conditions. The evolving conditions are weather conditions, workplace temperature, ship motion, noise and vibration, and workload and stress. For example, extreme weather condition affects seafarers' performance, increasing the chances of error, and, consequently, can cause injuries or fatalities to personnel. An effective human error probability model is required to better manage maintenance on-board ships. The developed model would assist in developing and maintaining effective risk management protocols. Thus, the objective of this study is to develop a human error probability model considering various internal and external factors affecting seafarers' performance. METHODS: The human error probability model is developed using probability theory applied to Bayesian network. The model is tested using the data received through the developed questionnaire survey of >200 experienced seafarers with >5 years of experience. The model developed in this study is used to find out the reliability of human performance on particular maintenance activities. RESULTS: The developed methodology is tested on the maintenance of marine engine's cooling water pump for engine department and anchor windlass for deck department. In the considered case studies, human error probabilities are estimated in various scenarios and the results are compared between the scenarios and the different seafarer categories. The results of the case studies for both departments are also compared. CONCLUSION: The developed model is effective in assessing human error probabilities. These probabilities would get dynamically updated as and when newinformation is available on changes in either internal (i.e., training, experience, and fatigue) or external (i.e., environmental and operational conditions such asweather conditions, workplace temperature, ship motion, noise and vibration, and workload and stress) factors.

Neurite outgrowth properties of calotropis procera: In search for a neuroprotectant

In view of the well-documented medicinal properties of Calotropis procera [CP], the present study was designed to evaluate the neuroprotective effect of the extract. We have prepared a methanolic extract of Calotropis procera and screen varying concentration of CP [20, 30, 40, 50 and 70microg/ml] for the stimulatory potency on neurite outgrowth. The stimulatory effect of CP on neurite outgrowth was assessed in primary hippocampal neurons. Neurite lengths were measured using optika provison analysis software. Neuritogenesis was further analyzed by immunostaining by using specific neuronal marker beta III-tubulin. The data show that neurite outgrowth from hippocampal neurons were significantly enhanced in the presence of CP [40microg/ml]. The most stimulatory neurite outgrowth effects were appeared after 48hrs incubation of neurons with CP [40microg/ml]. These data confirm that CP extract could promote invitro hippocampal neurite outgrowth in a dose-dependent manner. Our results indicate that CP can be used as a healthy dietary supplement for the cognitive functions of the brain

Vitex negundo induces an anticonvulsant effect by inhibiting voltage gated sodium channels in murine Neuro 2A cell line

Vitex negundo [Vn] extract is famous for the treatment of neurological diseases such as migraine and epilepsy. These neurological diseases have been associated with abnormally increased influx of sodium ions into the neurons. Drugs that inhibit voltage gated sodium channels can be used as potent anti-epileptics. Till now, the effects of Vn on sodium channels have not been investigated. Therefore, we have investigated the effects of methalonic fraction of Vn extract in Murine Neuro 2A cell line. Cells were cultured in a defined medium with or without the Vn extract [100 microg/ml]. Sodium currents were recorded using whole-cell patch clamp method. The data show that methanolic extract of Vn inhibited sodium currents in a dose dependent manner [IC50 =161microg/ml]. Vn [100 microg/ml] shifted the steady-state inactivation curve to the left or towards the hyper polarization state. However, Vn did not show any effects on outward rectifying potassium currents. Moreover, Vn [100 microg/ml] significantly reduced the sustained repetitive [48 +/- 4.8%, P<0.01] firing from neonatal hippocampal neurons at 12 DIV. Hence, our data suggested that inhibition of sodium channels by Vn may exert pharmacological effects in reducing pain and convulsions

Neuroprotective capabilities of Vitex negundo in primary hippocampal neurons

Vitex negundu [Vn] is a well-known aromatic shrub commonly used as a traditional folk medicine famous for its potential pharmacological and biological activities. Several chemical compounds are extracted and identified from the different parts of the Vn such as leaves, root, seeds and flowers. Number of researches reported the herb as antimicrobial, anti-androgenic, anti-osteoporotic, and anti-tumour, anti-cancer, anti-inflammatory, anti-oxidant, anti-hyperglycemic and hepatoprotective. The effects of Vn on neurite outgrowth have not been identified till now. Therefore present study was designed to investigate the neurite outgrowth effects of Vn extract in hippocampal neurons. Neurons from P0 mice were isolated and cultured in defined medium containing the different concentrations of Vn [20, 30, 40, 50, 100, 150 and 200 microg/ml] for 48 hrs. The presence of the neurites was confirmed by using betaIII-tubulin antibody which specifically labels only the neurites. Morphometric analysis was done by using Optika Pro-Vision software. The data show that Vn at 30 and 40 microg/ml significantly increased the mean average length of the longest neurite whereas at 150 and 200 microg/ml it significantly decreased the mean average length of the 10 longest neurite in hippocampal neurons. Nevertheless Vn did not show any significant effects on the sum of all the neurite lengths at any concentrations tested. Taken together the result shows that methanolic extract of Vn has potential to produce long neurites at 30 and 40 microg/ml and therefore can be act as a neuroprotective agent in the future drug development

Relationship of the Van Herick grading system with peripheral iris configuration and level of iris insertion

Objective: To determine the relationship of the van Herick angle grading system with the level of iris insertion and peripheral iris configuration

Study Design: Observational study

Place and Duration of Study: Eye department, Combined Military Hospital, Malir Cantt., Karachi, from May to October 2015

Methodology: Sixty-five eyes of 65 patients were recruited. Anterior chamber depth at the temporal limbus was measured as a fraction of corneal section thickness using van Herick technique and graded on the standard 4-point scale of the van Herick grading system. Gonioscopy of the temporal quadrant was performed with a Posner 4 mirror goniolens and both the true level of iris insertion and peripheral iris configuration were recorded on a 4-point scale so as to equate with the van Herick 4-point grading system. Spearman's rho test was applied to determine the relationship of the van Herick grading system with level of iris root insertion and peripheral iris configuration

Results: A moderate positive correlation between van Herick grade and peripheral iris configuration was found which was statistically significant [rs=0.42, p < 0.001]. A statistically significant and moderate positive correlation was also detected between van Herick grade and the level of iris insertion [rs=0.45, p < 0.001]

Conclusion: The van Herick grade has a moderately positive relationship with the peripheral iris configuration and true level of iris insertion

New markers in sepsis

Sepsis is a complex disease associated with high morbidity and mortality. Early diagnosis, administration of appropriate antimicrobial therapy and source control are the cornerstones of treatment. The use of biomarkers to guide management of sepsis has been extensively investigated and is well described in the literature. However no single biomarker has been validated for the diagnosis of sepsis, prognostication or to guide antimicrobial prescribing. So their role in clinical practice is still unclear. An approach that integrates data from various combinations of biomarkers with the clinical information available at the bedside shows promise but requires further evaluation

impact of pterygium excision on corneal astigmatism

Objective: To compare the corneal astigmatism before and after the excision of pterygium and also to determine the correlation of pterygium size with the postoperative corneal astigmatism. Study Design: Cross-sectional interventional study. Place and Duration of Study: Eye Department, Combined Military Hospital, Abbottabad, from May 2011 to March 2012

Methodology: Thirty patients underwent pterygium excision. Pre-operatively Snellen visual acuity, manifest refraction and slit lamp examination was done. The size of the pterygium was recorded in mm by projecting a horizontal slit lamp beam from the limbus to the apex. All the pterygium were equal to or greater than 2.5 mm. Keratometry was performed with an automated keratometer. Keratometric data was recorded pre-operatively and at 28 days postoperatively. Wilcoxon signed rank test was used for comparing the pre-operative and the postoperative corneal astigmatism. Spearman's rank order was calculated to observe correlation of pterygium size with the postoperative astigmatism

Results: The median [mean rank] pre-operative astigmatism of 2.25 [15.50] reduced to a median [mean rank] postoperative astigmatism of 1.30 [14.96]. This decrease in the postoperative astigmatism was statistically significant [p < 0.001]. There was a statistically non-significant correlation between the postoperative astigmatism and the pterygium size [rs = -0.29, p = 0.12]

Conclusion: Pterygium excision caused significant reduction in corneal astigmatism

Bronchoscopy as a rescue therapy in patients with status asthmaticus: two case reports and review of literature

Management of status asthmaticus requires more than guidelines-guided therapy. Occasionally, uncommon therapeutic interventions and procedures may provide significant benefits. The role of bronchoscopy in fatal asthma is still not clearly defined. We illustrate two cases of severe status asthmaticus on mechanical ventilation who showed remarkable improvement after therapeutic bronchoscopy

Protocolized eye care prevents corneal complications in ventilated patients in a medical intensive care unit

Eye care is an essential component in the management of critically ill patients. Standardized eye care can prevent corneal complications in ventilated patients. This study was designed to compare old and new practices of corneal care for reduction in corneal complications in ventilated patients. This study was done in three phases each of six month duration. Phase 1 was the ongoing practice of eye care in the unit. Before the start of phase 2, a new protocol was made for eye care. Corneal complications were observed in terms of haziness, dryness, and ulceration. All nursing staffs were educated and made compliant with the new protocol. In phase 2, a follow-up audit was done to check the effectiveness and compliance to protocol. In phase 3, a follow-up audit was started 3 months after phase 2. In phase 1, total ventilated patients were 40 with 240 ventilator days. The corneal dryness rate was 40 per 1000 ventilator days while the haziness and ulceration rate was 16 per 1000 ventilator days each. In the second phase 2, total ventilated patients were 53 making 561 ventilator days. The rate of corneal haziness and dryness was 3.52 and 1.78 per 1000 ventilator days, respectively, with no case of corneal ulceration. In phase 3, the number of ventilated patients was 91 with 1114 ventilator days. The corneal dryness rate was 2.69 while the haziness and ulceration rate was 1.79 each. Protocolized eye care can reduce the risk of corneal complications in ventilated patients

Airway management and hemodynamic response to laryngoscopy and intubation in supine and left lateral positions

Intubation in the lateral position is desirable in several conditions. We compared the technical ease and hemodynamic response to laryngoscopy and intubation in the lateral [group L] and supine [group S] positions in 120 patients with normal airway in a prospective randomized controlled study. This was a randomized, controlled observational study. All intubations were performed by a single investigator experienced in lateral intubation. Ventilation score with bag and mask ventilation, laryngoscopy duration and attempts, application of external pressure and Cormac and Lehane grade were measured. Blood pressure and heart rate were observed before and after induction of anesthesia, after laryngoscopy/intubation and then at one minute interval for 6 minutes. 90% of patients in group S were ventilated by a single operator compared to 17% in group L. Duration of laryngoscopy was significantly longer in group L [32 seconds] compared to group S [12 seconds] [p<0.001]. 78% of the patients in group S had Cormack and Lehane grade 1 versus nil in group L. External pressure was required in 58% patients in group L and 5% in group S. In intra-group comparison at specified time lines no difference was observed in HR but the changes in BP were significantly higher in the lateral position [P-value <0.001]. Ventilation and intubation in lateral position was more difficult technically than in the suprine position, and the BP response was exaggerated in the lateral position

surgical intervention an ideal treatment of De-Quervain's disease?

To evaluate the outcome of surgical treatment of DeQuervain s disease. Prospective study conducted from January 2004 to February 2005. Khyber Teaching Hospital, Peshawar. Clinically diagnosed cases of DeQuervain s disease who failed to respond to conservative treatment i.e. analgesics, splinatge and local steroid injections. The above mentioned patients were operated under local anesthesia and the tendons of extensor pollieis brevis and abductor pollicis longus were released. The patients were followed up for a minimum of four months to assess the clinical outcome of the procedure. There were 23 females and two male patients. Their ages ranged from 35 to 55 years with a mean age of 40 years. The two male patients were exposed to repetitive friction in terms of profession while all female patients were manual workers. Five out of 23 female patients had rheumatoid arthritis. The results of surgery showed that 22 patients had complete resolution of symptoms; in two patients the procedure ended up with failure as symptoms did not resolve and in one patient there was temporary skin paresthesia over the anatomical snuff box. Surgical intervention has promising results in DeQuervain s disease, when medical treatment fails