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Biomedical subjects

R M Khan

Publications and source records attributed to R M Khan.

At least 37 records · Page 2Linked to original sources
PubMed1996

Modified Laryngeal Mask Airway--a useful aid to fiberoptic intubation.

Modified Laryngeal Mask (MLMA) aided fiberoptic intubation (FOI) using larger than 6 mm ID endotracheal tube was studied in 25 adult patients and compared to unaided FOI in another 25 patients. MLMA aided FOI was successful in 96% cases compared to 56% in the unaided group. Furthermore, the time to successful intubation was increased by 67.1% when FOI was attempted without MLMA aid which was statistically significant (P < 0.001). However, maximum fluctuations in the heart rate and mean arterial pressure in the immediate post-intubation period were statistically insignificant between the groups. We conclude that MLMA not only adds to success rate of FOI but also significantly reduce the FOI time in adult patients.

Adult↗
PubMed1995

Hypobaric spinal anaesthesia with bupivacaine (0.1%) gives selective sensory block for ano-rectal surgery.

Twenty adult male patients undergoing anorectal surgery in the jackknife position under spinal anaesthesia were studied for the anaesthetic properties of 5 ml hypobaric 0.1% bupivacaine. The patients were positioned in the prone, jack-knife position with a pillow under the hips and with an operating table break angulation of 30 degrees with head down tilt of 20 degrees. In this position a 25-gauge Quincke spinal needle was inserted intrathecally through L3-4 and 5 ml solution, prepared by mixing 1 ml bupivacaine 0.5% with 4 ml of distilled water with a specific gravity of 1.001 at 20 degrees C, was given over 15-20 sec. Onset time, progression and upper level of sensory blockade evaluated by pin prick, and the extent of motor block (1 = full motor movement at ankle and knee joint, 2 = restricted motor movements, 3 = full motor block, no movements) were measured at one minute intervals for the first five minutes, then every five minutes for 30 min. The number of dermatomes blocked was also noted. The median level of cephalad sensory blockage was of L1, with a range from T10-L3. On average, nine dermatomes were blocked (range 7-12). Motor blockade was not observed in any patient. Changes in heart rate and blood pressure were minimal. The average duration of postoperative analgesia was 339.5 +/- 182.9 min. Post-spinal headache was not observed in any patients. In conclusion, 5 ml intrathecal hypobaric bupivacaine, 0.1%, provided excellent perioperative analgesia without motor blockade and haemodynamic stability in patients undergoing anorectal surgery in jackknife position.

Adolescent↗
PubMed1995

CPAP with air and oxygen to non-ventilated lung improves oxygenation during one lung anaesthesia.

Ten adult patients undergoing one lung ventilation for elective thoracotomy were selected. All these patients failed to maintain oxygen saturation (SaO2) > 90% despite administration of 100% oxygen to the non-ventilated lung (NVL). These patients were studied for the efficacy of continuous positive airway pressure (CPAP) of the NVL using air and oxygen combination (FiO20.5) employing a variable FiO2CPAP system. It was observed that application of CPAP (5-10 cm H2O) with a mixture of air and oxygen to the NVL increased the SaO2 > 90% in all these patients. This could be attributed to nitrogen in air which prevented absorption atelectasis in the NVL. This produced a better ventilation/perfusion ratio and hence the increased oxygen saturation.

Adult↗
PubMed1994

Post-anaesthetic pulmonary oedema following upper airway obstruction.

Twelve cases of post-anaesthetic pulmonary oedema (PO) secondary to upper airway obstruction (UAO) are reported. All were adult male patients undergoing uneventful elective surgical procedure under general anaesthesia. Post-anaesthetic laryngospasm was the single most important factor for the upper airway obstruction (UAO) in 5 (41.6%) patients. PO secondary to partial UAO in drowsy patients was observed in 4 (33.3%) patients. UAO due to foreign body was responsible for PO in two patients. A combination of negative intrathoracic pressure, hypoxia and associated hyperadrenergic state were the most likely causes of PO in these patients with UAO. Early recognition, maintenance of patent airway and adequate oxygenation via face mask or endotracheal tube with mechanical ventilation resolved the syndrome within 6-36 hours in all of these patients. Invasive haemodynamic monitoring or aggressive drug therapy were not applied in any of the patients. A heightened awareness among anaesthesiologists of the varied causes of post-anaesthetic UAO leading to PO may help reduce the occurrence and facilitate early management of the potential complications.

Adolescent↗
PubMed1993

Blood conservation and autotransfusion in cardiac surgery.

Blood conservation techniques of withdrawal of blood just before surgery, intraoperative blood salvage with Solcotrans (Solco Basle [UK] Ltd.), and profound hemodilution were used in 14 patients undergoing open heart surgery (group I) and compared with equally matched 14 patients who had profound hemodilution only during cardiopulmonary bypass (CPB) and acted as controls (group II). Group I patients required a mean of 255 mL of homologous blood per patient to achieve a target hemoglobin of 8 g/dL compared to group II patients who required a mean of 1,011 mL per patient (p = 0.0001). By using autologous blood there was a marked reduction in homologous blood exposure. Eight patients in group I and two patients in group II required no homologous blood. No adverse events occurred. In the process of conservation of blood in open heart surgery, we found the combination of the above techniques used in Group I patients to be safe and effective.

Adult↗
PubMed1993

Effects of benzodiazepine agonist, antagonist and inverse agonist on ethanol-induced changes in beta-endorphin levels in specific rat brain regions.

The present study was conducted to evaluate and compare effects of the benzodiazepine agonist diazepam, antagonist flumazenil and inverse agonist RO 15-4513 on ethanol-induced changes in beta-endorphin (beta-EN) levels in specific rat brain regions. Male Sprague-Dawley rats (150-200 g) adapted to a 12-hour light:12-hour dark illumination cycle were used in this study. Ethanol (3 g/kg as 22.5% solution in saline), flumazenil (10 mg/kg), RO 15-4513 (10 mg/kg), diazepam (2 mg/kg) or a combination of ethanol (3 g/kg) and flumazenil (10 mg/kg), RO 15-4513 (10 mg/kg) or diazepam (2 mg/kg) were administered intraperitoneally to rats at 7.00 h. Control animals were injected with saline. Animals were sacrificed by decapitation 1 h after injection; the brains were immediately removed; the cortex, hippocampus and hypothalamus were dissected and their beta-EN levels measured by radioimmunoassay. Ethanol administration significantly increased beta-EN levels in the hippocampus and hypothalamus but had no effect on beta-EN levels in the cortex. Similar increases in beta-EN levels in the hippocampus and hypothalamus also occurred following either flumazenil or diazepam. On the other hand, RO 15-4513 significantly increased beta-EN levels in the cortex and hypothalamus. When flumazenil was concurrently administered with ethanol, it completely reversed the ethanol effects in the hippocampus but failed to do so in the hypothalamus. Concurrent administration of RO 15-4513 with ethanol also reversed the ethanol-induced rise of beta-EN in the hypothalamus. However, concurrent administration of diazepam and ethanol did not block the increase in beta-EN levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Affinity Labels↗
PubMed1993

Evaluation of patient controlled sedation and analgesia for ESWL.

This study was designed to evaluate the quality of sedation/analgesia and patient cooperation provided by Patient Controlled Sedation & Analgesia (PCSA) using propofol and fentanyl (Group II) when compared with anesthetist administered propofol/fentanyl (Group I) in 32 ASA I & II patients undergoing ESWL of renal or ureteric stones. Demographics of the patients and the duration of ESWL were similar in both groups. Dose of propofol/fentanyl used during the procedure was significantly higher in Group I patients as compared to group II (p less than 0.05). Interpatient variability in propofol requirement was reflected in both groups in the lack of significant correlation between propofol dose and procedure duration. PCSA provided a marginally higher degree of patient and surgeon satisfaction scores as compared to anesthetist administered propofol/fentanyl. Quick recovery was more consistent in the PCSA group as compared to group I patients.

Adult↗
PubMed1993

Ventilation with nitrous oxide during open cholecystectomy increases the incidence of postoperative hypoxemia.

The effect of intraoperative use of air versus nitrous oxide (N2O) on postoperative oxygen (O2) saturation in blood was evaluated in 40 ASA Class I and II patients undergoing elective, open cholecystectomy. Patients were allocated randomly to two groups on the basis of whether they received air (Group A, n = 20) or N2O (Group B, n = 20) intraoperatively. Oxygen saturation was recorded on arrival of the patients in the ward, 24 h, and 48 h postoperatively. Although mean O2 saturation did not differ significantly (P > 0.05) between the groups over the first 24 h postoperatively, it was significantly higher (P < 0.05) in Group A as compared to Group B 48 h postoperatively. Incidence of hypoxemia (O2 saturation < 90%) was 40% in Group B as compared to 0% in Group A at the end of 48 h postoperatively. We conclude that the use of N2O during cholecystectomy is associated with a higher incidence of hypoxemia postoperatively.

Adult↗
PubMed1992

Effect of indomethacin on the pharmacokinetics of methotrexate in rabbits.

The interaction between indomethacin (IND) and methotrexate (MTX) was investigated in rabbits. The study was designed so as to evaluate the effect of IND (1 mg h-1) during a continuous MTX infusion (1 x 2 mg kg-1) over 240 min. IND was injected i.v. at hourly intervals after a steady state MTX concentration had been established. Plasma MTX concentration before and after IND did not differ significantly (p greater than 0.05). The elimination half-life (t1/2 beta) calculated during the washout interval (mean +/- SD) was 47 x 4 +/- 21 x 5 min which is close to that calculated in a reference group of rabbits. This excludes the possibility of delayed elimination as responsible for this toxicity. The toxicity of this combination was confirmed despite the absence of significant pharmacokinetic changes. It is possible that the toxic interaction was caused by enhanced cytotoxic effect of MTX.

Animals↗