Adverse heart rate responses during beach-chair position for shoulder surgeries - A systematic review and meta-analysis of their incidence, interpretations and associations.

BACKGROUND AND AIMS: Evaluations of adverse heart rate (HR)-responses and HR-variations during anaesthesia in beach-chair-position (BCP) for shoulder surgeries have not been done earlier. We analysed the incidence, associations, and interpretations of adverse HR-responses in this clinical setting. METHODS: We performed a meta-analysis of trials that reported HR-related data in anaesthetised subjects undergoing elective shoulder surgeries in BCP. Studies included prospective, randomised, quasi-randomised and non-randomised, controlled clinical trials as well as observational cohorts. Literature search was conducted in MEDLINE, EMBASE, CINHAL and the Cochrane Central Register of Controlled Trials of the 21st century. In the first analysis, we studied the incidence and associations of bradycardia/hypotension-bradycardia episodes (HBE) with respect to the type of anaesthesia and different pharmacological agents. In the second, we evaluated anaesthetic influences, associations and inter-relationships between monitored parameters with respect to HR-behaviours. RESULTS: Among the trials designed with bradycardia/HBE as a primary end point, the observed incidence of bradycardia was 9.1% and that of HBE, 14.9% and 22.7% [(for Interscalene block (ISB) ± sedation) subjects and general anaesthesia (GA) + ISB, respectively]. There was evidence of higher observed risk of developing adverse HR-responses for GA subjects over ISB (Risk Difference, P < 0.05). Concomitant use of ß-agonists did not increase risk of HBEs (P = 0.29, I 2= 11.4%) or with fentanyl (P = 0.45, I 2= 0%) for ISB subjects (subgroup analysis). Fentanyl significantly influenced the HR-drop over time [meta-regression, estimates (standard error), 14.9 (5.4), 9.8 (4.3) and 17 (2.6); P = 0.007, 0.024 and <0.001; for early, mid and delayed periods, respectively] in GA subjects. With respect to number of subjects experiencing cerebral desaturation events (CDEs), total intravenous anaesthesia (TIVA)- propofol had higher risk over inhalational anaesthesia (P = 0.006, I 2 = 86.7%). Meta-correlation analysis showed relationships between the HR and rSO2(regional cerebral oxygen saturation) or SjvO2(jugular venous oxygen saturation) values (r = 0.608, 95%CI, 0.439 to 0.735, P < 0.001, I 2= 77.4% and r = 0.397, 95%CI, 0.151 to 0.597, P < 0.001, I 2= 64.3%, respectively). CONCLUSIONS: There is not enough evidence to claim the associations of adverse HR-responses with any specific factor. HR-fall is maximal with fentanyl and its variability is associated with changes in rSO2. Fall in rSO2 could be the common link triggering adverse HR-responses in BCP.

Comparative Study between Propofol and Dexmedetomidine for Conscious Sedation in Patients Undergoing Outpatient Colonoscopy.

INTRODUCTION: Colonoscopy is a mildly painful procedure requiring conscious sedation. Though propofol is a widely used anesthetic agent in day-care procedures due to its rapid onset and quick recovery has a drawback of requiring resuscitation maneuvers more often than the conventional methods. Dexmedetomidine, a newly introduced, highly selective α2-adrenergic receptor agonist possessing hypnotic, sedative, anxiolytic, sympatholytic, and analgesic properties with impressive safety margin, needs to be explored for use in conscious sedation for colonoscopy procedure among South Indian population. MATERIALS AND METHODS: A prospective randomized comparative study was conducted on patients aged between 25 and 60 years with the American Society of Anesthesiologist physical status classes I and II posted for colonoscopy under monitored anesthesia care. Study group was randomly divided into two groups and administered propofol and dexmedetomidine. The primary outcome variable was assessments of sedation scores between the two groups. Secondary outcome variables were pain score assessments, hemodynamic comparisons, and adverse events among the two groups. Appropriate statistical tests were applied to compare the findings. RESULTS: After comparisons between the two groups, we found that patients on dexmedetomidine had similar sedation score as that of patients on propofol. However, there was a significantly higher incidence of systemic hypotension. Requirement of rescue analgesia and adverse events and other hemodynamic fluctuation were similar in both the groups. CONCLUSION: We conclude that dexmedetomidine has similar efficacy as propofol for conscious sedation required during colonoscopy. Occurrence of systolic hypotension was, however, significantly more among the group receiving dexmedetomidine.

Motor response evaluation during brachial plexus block anesthesia: An ultrasonography aided study.

BACKGROUND: The sparing of ulnar nerve often leads to the failure of the upper limb blockade. It has been claimed that local anesthetic injection at the site of stimulator evoked finger flexion response is associated with highest success rate of a successful block. The lower trunk stimulation of plexus should yield similar results as this trunk contributes significantly for median and ulnar nerves of hand and forearm. MATERIALS AND METHODS: The patients with intact anatomical upper limb structures underwent (a) combined ultrasound (USG) assisted nerve stimulator evoked motor response evaluation or in (b) open brachial plexus trunk stimulation evaluations. The individual patient's lower trunk stimulation motor responses were documented. RESULTS: When combined the results of both USG and open plexus groups, wrist flexion was seen in 52%, finger flexion in 61% and forearm pronation or twitches of anterior compartment in 48% of total subjects studied. These responses were noted either separately or in combinations. CONCLUSION: We conclude other than finger flexion, the wrist flexion the forearm twitches, pronation and wrist adduction may be used for lower trunk blockade and thus for higher accuracy.