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Biomedical subjects

S Ganapathy

Publications and source records attributed to S Ganapathy.

At least 19 recordsLinked to original sources

Propofol patient-controlled sedation during hip or knee arthroplasty in elderly patients.

PURPOSE: Little information is available regarding the use of patient-controlled sedation (PCS) among the elderly. This study evaluated the safety and efficacy of propofol PCS among elderly patients undergoing hip or knee arthroplasty. METHODS: Forty patients, aged 65-78 yr, undergoing hip or knee arthroplasty under regional anaesthesia were randomized to receive propofol PCS (dose = 0.3 mg.kg-1, delay = three min; n = 20) or anaesthetist-administered midazolam-fentanyl sedation (n = 20). Sedation, anxiety and discomfort visual analogue scores (VAS) were measured, by an independent observer, preoperatively, immediately at the end of surgery and one hour following admission to the postanaesthetic care unit (PACU). Cognition was evaluated, using an abbreviated Mini Mental Status Examination, preoperatively and in the PACU. Patient satisfaction, based on VAS and a brief questionnaire, was measured in the PACU. The incidence of intraoperative complications was also compared. RESULTS: Patient satisfaction was high in each group. Sedation and anxiety VAS were similar in each group. A high incidence of pain with drug injection was noted among patients receiving propofol (80%). Transient deeper levels of sedation (6 vs 1; P = 0.05) were observed more commonly in the propofol PCS group. CONCLUSION: Propofol PCS provides effective sedation. Using a propofol dose of 0.3 mg.kg-1, transient episodes of deeper sedation were noted more frequently among patients receiving PCS. These episodes did not require intervention but, suggest that this propofol PCS dose approaches the limit of safety and should be further reduced for some elderly patients.

Adjuvants, Anesthesia

Solid-state CP/MASS 13C-NMR spectroscopy: a sensitive method to monitor enzymatic hydrolysis of chitin.

The time-course hydrolysis of colloidal chitin by the chitinase complex isolated from Myrothecium verrucaria was monitored using solution and solid-state 13C-NMR spectroscopy. The solution NMR studies showed the presence of N-acetylglucosamine (GlcNAc) as the sole product of hydrolysis. Solid-state 13C CP/MASS studies, on the other hand, indicated the presence of high molecular weight oligomers as well as GlcNAc. The linewidth of the C1 carbon of the oligomers obtained after hydrolysis is found to be less than that of the unhydrolyzed sample. The linewidths calculated from the spin-spin relaxation times (T2) of colloidal chitin and its products of hydrolysis were in the restricted range of 40-50 Hz, compared with the observed linewidths of 143-123 Hz. Peak area measurement on monomer to polymer/oligomer indicated an initial slow formation of the monomer, GlcNAc. From the NMR data, the involvement of endo-enzymes in the initial phase of hydrolysis is suggested.

Acetylglucosamine

Eutectic mixture of local anaesthetics is not effective for extracorporeal shock wave lithotripsy.

PURPOSE: Eutectic mixture of local anaesthetics (EMLA) produces cutaneous analgesia. This randomized, double blind, placebo controlled study evaluated the efficacy of EMLA cream during extracorporeal shock wave lithotripsy (ESWL) using the Dornier MFL 5000 lithotripter. METHODS: Patients scheduled to undergo lithotripsy of renal or pelviureteric junction stones were randomized to receive either 30 g EMLA cream (E) or placebo (P) over the kidney area 60-90 min before the procedure. During lithotripsy all patients received alfentanil via a PCA machine (dose--10 mu.kg-1, lockout time--three minutes, no basal infusion). Additional bolus doses of 5 micrograms.kg-1 alfentanil were administered by the anaesthetist if analgesia was inadequate. Visual analogue scores (VAS) for pain were documented prior to application of the cream. On arrival in the post anaesthesia care unit VAS pain scores were documented for maximum pain and average pain felt during the procedure as well as for satisfaction of the analgesic technique used. Total time spent in the PACU and the Aldrete scores on arrival were compared. RESULTS: Eighty-three patients completed the study. Demographic data were similar between the two groups. Also, VAS for maximal pain, average pain and satisfaction and the total number of shock waves were similar although the EMLA group received more shock waves at the lower energy level (kV) (P < 0.0001). Total dose of alfentanil, dose as boluses, rate of alfentanil use, total number of PCA attempts and missed attempts were similar. The incidence of adverse events such as bradypnoea, airway obstruction, transient hypoxaemia, pruritus and nausea were small and similar. There was a slightly higher incidence of inadequate analgesia documented by the anaesthetist in the EMLA group. There was no difference between the groups with regards to duration of stay in the PACU, incidence of nausea or Aldrete scores on admission to PACU. CONCLUSIONS: During lithotripsy EMLA cream does not modify the pain perceived nor does it have any opioid sparing effect. It does not facilitate early discharge from the PACU.

Adult

Continuous epidural infusion of ropivacaine for the prevention of postoperative pain after major orthopaedic surgery: a dose-finding study.

PURPOSE: A dose-finding study to investigate the use of epidural infusions of ropivacaine for postoperative analgesia following orthopaedic surgery. METHODS: This was a randomized, double-blind study. Surgery was performed using a combination of a lumbar epidural block utilizing ropivacaine 0.5% and a standardized general anaesthetic. Postoperatively, an epidural infusion of the study solution (saline, ropivacaine 0.1%, 0.2% or 0.3%) was started at the rate of 10 ml.hr-1 and continued for 21 hr after arrival in the PACU. Analgesia was supplemented with PCA morphine (dose = 1.0 mg, lock-out = 5 min). RESULTS: Forty-four patients completed the study. The ropivacaine 0.1%, 0.2%, 0.3% groups required less morphine over the 21 hr than the saline group (P < 0.01). The VAS pain scores were also lower in the three ropivacaine groups (P < 0.001). The ropivacaine groups maintained sensory anaesthesia to pinprick when compared with saline (P < 0.05). The motor block in the 0.3% group was significantly higher than the saline group at all times (P < 0.05), and higher than the 0.1% group at eight hours (P < 0.01), while the 0.2% group had higher Bromage scores than saline at 4 and 21 hr (P < 0.05). CONCLUSIONS: The use of continuous epidural infusions of ropivacaine 0.1%, 0.2% and 0.3% at 10 ml.hr-1 improved postoperative pain relief and decreased PCA morphine requirements in patients undergoing major orthopaedic surgery. The 0.1% and 0.2% concentrations produced similar sensory anaesthesia with less motor blockade than the 0.3% concentration.

Adult

Postoperative cognitive impairment in the elderly. Choice of patient-controlled analgesia opioid.

This study evaluated the safety and cognitive impact of patient-controlled analgesia with fentanyl compared to patient-controlled analgesia with morphine among elderly postoperative patients. In addition, two screening tests for cognitive impairment, the Mini Mental Status Exam and the Short Portable Mental Status Questionnaire, were compared. Ninety-six elderly patients were randomly allocated to receive patient-controlled analgesia with either fentanyl or morphine following hip or knee arthroplasty. Patients were evaluated postoperatively for clinical confusion, cognitive function test results, adequacy of analgesia, drug use and complications. Fentanyl produced less depression in postoperative cognitive function compared to morphine. The incidence of clinical confusion was not statistically different between groups (4.3% for fentanyl versus 14.3% for morphine). Fentanyl patients used more opioid based on a dose ratio of 100:1 suggesting that this dose ratio is inadequate. The incidence of urinary retention was lower in the fentanyl group. A poor agreement between the two tests of cognitive impairment mandates caution when peri-operative cognitive function is compared using different tests.

Aged

A controlled clinical trial of short-course chemotherapy for tuberculoma of the brain.

OBJECTIVE: The efficacy of a short-course regimen in the treatment of brain tuberculoma and computerised tomography (CT) scan appearance before, during and after antituberculosis treatment was studied in a controlled clinical trial. DESIGN: Patients aged over 5 years with tuberculoma of the brain diagnosed by CT scan were randomly allocated to one of the following 2 regimens: Regimen 1: rifampicin, isoniazid and pyrazinamide daily for an initial 3 months followed by rifampicin and isoniazid twice-weekly for 6 months. Regimen 2: rifampicin, isoniazid and pyrazinamide thrice-weekly for an initial 3 months followed by rifampicin and isoniazid twice-weekly for 6 months. The patients were followed intensively for 2 years from the start of treatment. RESULTS: Of the 108 patients analysed (regimen 1: 56, regimen 2: 52), at the end of treatment clinical status was normal in 91% in regimen 1 and 88% in regimen 2. Of the 91 patients with scan assessments, CT scan lesions disappeared at 24 months in 77% of 47 patients in regimen 1 and 80% of 44 in regimen 2, and in both groups 88% of the patients were clinically normal. None had relapses requiring treatment. CONCLUSIONS: Short-course regimens of 9 months' duration are effective in the treatment of tuberculoma of the brain; clinical recovery was faster than scan clearance.

Adolescent

Jejunal disaccharidases in protein energy malnutrition and recovery.

The jejunal disaccharidases, sucrase, maltase and lactase, were determined in jejunal biopsies obtained from 43 malnourished children and 10 controls. In the study group, 63% were girls and 93% had severe malnutrition. Lactase activity was significantly reduced in third and fourth degree malnutrition (p < 0.05 and p < 0.005, respectively), but maltase activity was significantly reduced only in the fourth degree malnutrition (p < 0.01). After recovery, maltase and sucrase activities showed a marginally significant increase (p = 0.06), where lactase showed no significant increase (p > 0.05). We conclude that jejunal disaccharidase activity decreases significantly with increasing severity of malnutrition, lactase being the most severely affected and the last to recover.

Biopsy

Anaesthesia for adenotonsillectomy: a comparison between tracheal intubation and the armoured laryngeal mask airway.

A prototype armoured laryngeal mask airway (LMA) was compared with tracheal intubation (ETT) for anaesthesia for adenotonsillectomy. Fifty-five children were randomised into the LMA group and 54 into the ETT group. During insertion of the LMA, peripheral oxyhaemoglobin desaturation (SpO2) < 94% occurred in ten patients (18.2%) and in seven patients (13%) during tracheal intubation (NS). After opening the Boyle-Davis gag, airway obstruction occurred in ten patients (18.2%) in the LMA group and in three patients (6%) in the ETT group (P = 0.07). In five patients (9%) the LMA was abandoned in favour of tracheal intubation. In all others (91%), when the need for adequate depth of anaesthesia was realized, a satisfactory airway was achieved more rapidly than with tracheal intubation (P < 0.001), and maintained throughout surgery. Manually assisted ventilation was required in all patients in the ETT group, mean duration 373 +/- 385 sec, and in 26 patients (52%) in the LMA group, mean duration 134 +/- 110 sec, P < 0.001. Mean end-tidal CO2 (PetCO2) was 45.5 +/- 6.21 mmHg in the ETT group and 46.6 +/- 6.09 in the LMA group (NS). The LMA did not limit surgical access. Heart rate, MAP and blood loss in the LMA group were 110 +/- 21, 74 +/- 9 mmHg and 1.92 +/- 1.22 ml.kg-1 respectively, compared with 143 +/- 13 (P < 0.001), 85 +/- 12 mmHg (P < 0.001) and 2.62 +/- 1.36 ml.kg-1 (P < 0.05) with tracheal intubation. Fibreoptic laryngoscopy at the end of surgery in 19 patients in the LMA group revealed no blood in the larynx.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoidectomy

Identification of the cause of separation (creaming) of lipid emulsions in intravenous infusion.

Over a 2-month period, white deposits were found in infusion sets delivering parenteral nutrition mixtures that included a lipid emulsion. When components of the infusion were mixed in the laboratory, separation (creaming) of the emulsion could be demonstrated, and this enabled us to predict the concentrations of the prescribed infusates that were likely to cream. Further investigations showed that creaming occurred when the lipid emulsion was mixed with heparin and calcium ions at concentrations above 1 U/ml and 1 mumol/ml, respectively.

Calcium

Efficiency of manual ventilation using the original EMO system.

The efficiency of the Oxford Inflating Bellows for intermittent positive pressure ventilation using a partially closed Heidbrink expiratory valve has been assessed by measuring the arterial carbon dioxide tension (PaCO2) after various intervals of IPPV on eight patients. It was found that satisfactory alveolar ventilation was achieved if a degree of hyperventilation was employed.

Carbon Dioxide