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Biomedical subjects

M G Serpell

Publications and source records attributed to M G Serpell.

At least 19 recordsLinked to original sources
PubMed1998

Malignant hyperthermia during prolonged surgery for tumour resection.

The onset of malignant hyperthermia in a patient during a prolonged anaesthetic for tumour resection is described. The onset was delayed with a gradual rise in heart rate and PETCO2 before becoming fulminant; muscle rigidity was not a feature. Other aspects of the patient's condition confused the presentation, delayed the diagnosis and may have been involved in precipitating the event. However, it responded rapidly to treatment and surgery was continued. A possible recrudescence occurred 18 h later. Malignant hyperthermia should be considered early in cases of unexplained tachycardia or rising PETCO2.

Adult↗
PubMed1997

Flow dynamics through spinal needles.

We examined the flow pattern produced when liquid dye was actively injected into a fluid medium at various flows through five different commonly used spinal needles. At all flows, the Whitacre-type needles produced a directional stream exiting at an angle from the longitudinal axis. At intermediate rates the stream developed tracks which disappeared at faster rates. The Quincke needle always produced an undeviated stream of dye and did not form tracks at any flow rate. When a perspex plate (representing the spinal cord) was interposed in front of the needle, the dispersion of dye was always unidirectional from the Whitacre needle and bidirectional from the Quincke needle. The dye adhered to the surface of the plate as a concentrated film at slow rates and at faster rates it dispersed turbulently for both types of needle.

Anesthesia, Spinal↗
PubMed1997

Randomized trial of different insufflation pressures for laparoscopic cholecystectomy.

BACKGROUND: The factors affecting cardiorespiratory changes and postoperative pain after laparoscopic cholecystectomy are poorly understood. The aim of this study was to assess these changes in patients undergoing laparoscopic cholecystectomy at an insufflation pressure of 7.5 or 15 mmHg. METHODS: Forty patients with similar preoperative characteristics were randomized, 20 to each group. RESULTS: There were no significant differences in intraoperative heart rate or cardiac index although the latter fell significantly soon after insufflation in both groups. The fall in cardiac index lasted longer (7 versus 2 min) and coincided with a slower rise in mean arterial pressure in those having 15 mmHg insufflation. Changes in peak airway pressure, end-tidal carbon dioxide and arterial blood gases were similar. After operation the low-pressure group had significantly less pain, better preservation of pulmonary function and were discharged home sooner (P = 0.015). CONCLUSIONS: Insufflation pressure significantly affects the haemodynamic changes and postoperative pain associated with laparoscopic cholecystectomy.

Carbon Dioxide↗
PubMed1996

High spinal block following an inadequate continuous spinal anaesthetic.

A patient is presented who obtained only an L1 sensory block, which was inadequate for her procedure, from continuous spinal anaesthesia despite appropriate doses of 0.5% plain bupivacaine. She then developed a high spinal block after an epidural was sited and a test dose given in the sitting position. The possible mechanisms for this are discussed.

Aged↗
PubMed1996

A comparison of epidural infusions of fentanyl or pethidine with bupivacaine in the management of postoperative pain.

A double-blind randomised clinical trial was undertaken in 40 patients undergoing major abdominal surgery. Postoperative pain relief was provided using epidural infusions of 0.06% bupivacaine with fentanyl 4 micrograms.ml-1 (n = 20) (group F) or with pethidine 1.5 mg.ml-1 (n = 20) (group P). Postoperative pain scores using a visual analogue scale (0-100 mm) were not significantly different between the two groups. Median pain scores were 0-19 mm at all times of assessment indicating that good analgesia was provided by both regimens. There was no significant difference between the epidural infusion rates in the two groups. The side effects and effect on pulmonary function were similar in each group. Nine patients were withdrawn from the study (four from group F, five from group P) due to failure of the epidural technique or other complications. Fourteen patients, equally distributed, required a total of 24 epidural 'top-ups' by an anaesthetist because of inadequate analgesia. We demonstrated no advantage with epidural pethidine over fentanyl when used by infusion in combination with bupivacaine in the management of postoperative pain.

Abdomen↗
PubMed1995

Effect of extraperitoneal carbon dioxide insufflation on intraoperative blood gas and hemodynamic changes.

Carbon dioxide pneumoperitoneum has been shown to produce respiratory and hemodynamic changes due to both CO2 absorption and the effects of increased intraperitoneal pressure. We have measured the blood gas, end-tidal CO2, and hemodynamic changes produced during extraperitoneal CO2 insufflation (n = 22). These have been compared with the changes occurring during CO2 pneumoperitoneum (n = 11) under standardized anesthetic conditions. The changes observed during pneumoperitoneum were consistent with previous descriptions. There was a median rise in arterial pCO2 of 1 kPa over the first 15-20 min, followed by a second phase of only gradual change. There was also an increase in mean arterial pressure of 18 mmHg during the insufflation period. We have found a similar magnitude of rise in arterial pCO2 during extraperitoneal insufflation (median 0.83 kPa), but the rate of rise was significantly slower (P < 0.05). In addition, there was no change in the mean arterial pressure during extraperitoneal insufflation. Our results suggest that extraperitoneal CO2 insufflation may be safer than CO2 pneumoperitoneum in patients with preexisting cardiorespiratory disease.

Adult↗
PubMed1995

Clinical characteristics of commonly used spinal needles.

The important features which determine the ease of use of spinal needles include rapid detection of cerebrospinal fluid, minimal delay before injection and low resistance to injection of local anaesthetic. We investigated these three parameters among the following 11 spinal needles: Becton-Dickinson 22 G, 25 G and 27 G Whitacre, 25 G and 27 G Quincke; B. Braun Spinocan 22 G, 25 G and 26 G Quincke; Vygon 25 G Whitacre, Portex 26 G Pencil Point and the 24 G Sprotte. Three needles of each type were tested using an artificial cerebrospinal fluid model maintained at body temperature and at two hydrostatic pressures of 12 and 50 cm of water. The Becton Dickinson 27 G Whitacre has an immediate detection time at both pressure heights, a reasonably short 'ready to inject' time and relatively low resistance to injection, which, together with a reported low rate of postdural puncture headache, would indicate that it is the most appropriate for spinal anaesthesia. The 25 G Whitacre types would be the next most suitable to use.

Anesthesia, Spinal↗
PubMed1994

The influence of nasal obstruction and its relief on oxygen saturation during sleep and the early postoperative period.

Nasal obstruction causes abnormal breathing patterns during sleep which often result in hypoxaemia. We studied the effect of nasal obstruction on arterial oxygen saturation in 20 healthy patients undergoing elective surgery which required bilateral nasal packing. Ten patients were subject to complete nasal obstruction while the remaining half had the obstruction relieved by the insertion of nasal cannulae. We found that nasal obstruction did not have any detrimental effect on the already low incidence of oxygen desaturation. There was no effect of the cannulae on the degree or frequency of hypoxaemia, although they did appear to improve the quality of sleep during the first postoperative night. They were more comfortable by day than simple packing alone and no adverse effects were observed.

Adolescent↗
PubMed1993

Intrathecal catheterization alone reduces autotomy after sciatic cryoneurolysis in the rat.

There is substantial evidence that sciatic cryoneurolysis (SCN, freeze lesion of the sciatic nerve) is a neuropathic pain model in the rat. During characterization of this model, SCN was performed 4 days after either a sham operation or the insertion of an indwelling intrathecal catheter preparatory to selective spinal drug administration. Body weight and autotomy scores were recorded for the next 22 days until sacrifice. The catheter group experienced significant weight loss (7.5%) by 4 days but rapidly regained to parity with the sham group. Autotomy scores and the frequency of severe autotomy (score > 3) were less at day 22 in the catheter group as compared with the sham-control group (p < 0.005, p < 0.03, respectively). Intrathecal catheterization itself effects the degree of behavioral response to neurogenic pain and thus, should be controlled for in studies using nociceptive animal models.

Animals↗