Effect of aminophylline on atracurium induced neuromuscular block

Background: theophylline is a naturally occurring methylxanthine that plays a role in various body functions through different mechanisms which include: phosphodiesterase enzyme inhibition, adenosine receptor antagonism etc. Its action on skeletal muscles to counteract fatigue and /or paralysis is through increasing acetylcholine release from motor nerve ending and increasing calcium concentrations within the muscle fiber itself. These combined effects therefore can antagonize nondepolarizing neuromuscular blockers through competitive antagonism in generally anesthetized patients. By the use of neuromuscular monitors, this effect could be evaluated and also to assess doses for reversal of residual drug-induced neuromuscular paralysis

Aim of the Study: the aim of this study was to evaluate the effect of theophylline on facilitating the recovery from atracurium induced neuromuscular blockade

Patients and methods: this study was performed on sixty [60] patients undergone elective surgeries had been expected to be about one-hour duration, with balanced general anesthesia after obtaining approval of the Ethical and Scientific Committee of Al Fayoum University, and written informed consents from patients. In this study, we used theophylline to antagonize atracurium induced muscle paralysis

Results: the results showed effective antagonism of atracurium paralyzing effect and rapid recovery from this paralysis

Conclusion: theophylline antagonizes atracurium induced neuromuscular blockade by several mechanisms either at the prejunctional or postjunctional level by AR antagonism or PDI or by RyR channel activation

Recommendations: we recommend further studies to be done on different categories of patients as diabetics, cardiac patients, elderly and etc. to assess its safety among those patients. We recommend further studies to be done on different categories of patients as diabetics, cardiac patients, elderly and etc. to assess its safety among those patients

Biphasic positive airway pressure ventilation [BIPAP] versus synchronized intermittent mandatory ventilation with pressure support [SIMV/PSV] after pediatric open heart surgery

Biphasic positive airway pressure [BIPAP] is a mode of ventilation, which allows unrestricted spontaneous breathing at any moment of the ventilatory cycle. Following open-heart surgery in adults, this mode of ventilation [BIPAP] is being accepted with a decrease in the need for sedation and a shorter time of intubation. In this study we compared BIPAP versus synchronized intermittent mandatory ventilation with pressure support [SIMV/PSV] following open-heart surgery in children for simple congenital cardiac anomalies. Twenty-four children aged 4-12 year undergoing repair of simple congenital cardiac anomalies, were randomly classified postoperatively into two equal groups. Group I ventilated by BIPAP mode of ventilation and Group II ventilated by SIMV/PSV mode of ventilation. Evita 4 ventilator was used in this study. Midazolam and morphine were used and adjusted according to comfort scale. In this study we compared between BIPAP and SIMV/PSV as regards hemodynamic data, ventilatory parameters, the needs for sedation and analgesia and the mean duration of endotracheal intubation. The two groups were comparable as regards the demographic data. There were significant differences between the two groups regarding better hemodynamic stability, increased comfort scale, and decreased the needs for sedation and analgesia in group I when compared to group II The ventilatory parameters were significantly better in-group I with better minute ventilation, lower PaCO[2] and higher PaO[2] when compared to group II. The mean duration of endotracheal intubation was significantly shorter in-group I when compared to group II. BIPAP is an effective, safe and easy to use mode of ventilation in children following open-heart surgery for simple congenital anomalies. Further assessment needed for its use in more complicated cases

Comparative study of dexmedetomidine, propofol, and midazolam for postoperative sedation following open heart surgery

Dexmedetomidine is a new, potent, and highly selective adrenoreceptor agonist. It has sedative-hypnotic, anxiolytic, analgesic, anesthetic-reducing and sympatholytic effects. Dexmedetomidine produced rapid and stable sedation in postsurgical ventilated patients, without significant respiratory or haemodynamic compromise, while maintaining a high degree of patient reusability and anxiety reduction. To study the different effects of Dexmedetomidine, in comparison to Propofol, and Midazolam for postoperative sedation in adult patients undergoing open heart surgery. Sixty patients, ASA physical status III-IV, aged 18-70 yr, with an ejection fraction > 45%, undergoing elective first time coronary artery bypass graft surgery [CABG], or single-valve replacement. All patients received a standardized fentanyl / sevoflurane anesthesia. During cardiopulmonary bypass 100 micro g/kg/min propofol was substituted for sevoflurane. Upon arrival to ICU, patients were randomized to three groups [n=20]: Group I [Dexmedetomidine] received dexmedetomidine 1 micro g/kg over 10-minute followed by infusion of 0.25-0.75 micro g/kg/hr. Group II [Propofol] received propofol 1mg/kg over 10-minute followed by infusion of 25-75 micro g/kg/min. Group III [Midazolam] received midazolam 0.1 mg/kg over 10-minute followed by infusion of 0.25-0.75 micro g/kg/min. Analgesia was provided with an infusion of morphine at 0.02 mg/kg/hr. Infusion rates were adjusted to maintain sedation within a predetermined range [Ramsay 2-4]. The infusion was terminated after six hours. Patients were weaned from mechanical ventilation when haemodynamic stability, haemostasis, normothermia and mental orientation were confirmed. Haemodynamic measurements and arterial blood gas tensions were recorded at specified times. The incidence of hypotension, hypertension, tachycardia, bradycardia, total dose of morphine, and the incidence of postoperative nausea, vomiting, and shivering were also recorded. There were no significant differences between the three groups for the time spent at each level of sedation, number of infusion rate adjustments, times to awakening and extubation and blood gases during weaning and after extubation [P=NS]. No patient in the three groups required tracheal reintubation. Dexmedetomidine treated patients required significantly lower dose of morphine during the first six hours after surgery 2.64 +/- 1.4 while in propofol 4.57 +/- 2.3 and in midazolam 5.12 +/- 2.8 [P<0.05]. Dexmedetomidine sedation was associated with a 25% incidence of bradycardia which was significantly higher than other two groups [P<0.05]. There were no other significant differences in haemodynamic values between the three groups. Postoperative shivering, nausea and vomiting occurred less frequently in dexmedetomidine group but without statistical significance [P >0.05]. It was concluded that, compared with a standard midazolam and propofol sedation regimens, dexmedetomidine 1 micro g/kg over a 10-minute period followed by an infusion of 0.2 5-0.7 5 micro g kg/hr, in selected cases, produced safe and clinically effective sedation, and relief of anxiety in patients recovering from cardiac surgery. It significantly reduced the analgesic requirements during the period of postoperative mechanical ventilation, without clinically apparent haemodynamic compromise, or respiratory depression after extubation

Nitroglycerine improves cardiac functions during gynaecological laparoscopic surgery in patients with valvular heart disease, transesophageal echocardiographic study

Gynaecological laparoscopic surgery is being increasingly applied to a variety of operations. In patients with valvular heart disease, there may be a dangerous haemodynamic effects of both Trendelenburg position and abdominal gas insufflation in the form of increased regurgant flow with subsequent decrease in the ejection fraction. With the use of vasodilators [Nitroglycerine] this effect was improved to a great extent with the possibility that we can use the laparoscopic technique in valvular cardiac patients provided that the heart is compensated. We used transesophageal echocardiography [TEE] to monitor cardiac performance, gas embolism, and hemodynamic effects of positioning and pneumoperitoneum in 20 females complaining of regurgant valvular heart disease [mild to moderate mitral, tricusped, or aortic valve regurge], undergoing laparoscopic gynaecological surgical procedures.A four-chamber view was used continuously, except at predetermined intervals, when a complete TEE examination for cardiac function was performed. Other clinical variables recorded include systolic, diastolic, and mean arterial blood pressure; heart rate [HR], pulse oximetric saturations; and end-tidal CO2. Baseline valvular incompetence was seen in 13 of the 16 patients when supine and asleep. After positioning for surgery and induction of pneumoperitoneum, TEE revealed valvular incompetence with regurgitation more pronounced from baseline in 15 of 16 patients. In one patient, gas entered the right atrium from the inferior vena cava, worsening tricuspid regurgitation. Nitroglycerine infusion 1-2 micro g/kg/min was started after abdominal insufflation to evaluate its effects on valvular dysfunction during pneumoperitoneum and Trendelenburg position. Hemodynamic variables and ejection fraction were tested by using repeated-measures analysis of variance for significance [P<0.05]. Trendelenburg position resulted in insignificant increase in heart rate and decrease in mean arterial pressure. Pneumoperitoneum with Trendelenburg position resulted in significant increase in systolic and mean arterial pressure, with significant reduction in ejection fraction. The regurgant flow was significantly increased in all patients as detected by TEE. With the use of nitroglycerine infusion, significant improvement EF, with significant increase in heart rate. Using TEE, the regurgant flow was significantly decreased in all patients after nitroglycerine infusion. Laparoscopic gynaecologic surgical procedures can be performed in patients with mild to moderate valvular regurgitations. Nitroglycerine infusion can be of great help to decrease the regurgant flow which is increased due to both the Trendelenburg position and pneumoperitoneum