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Biomedical subjects

D A Rocke

Publications and source records attributed to D A Rocke.

At least 19 recordsLinked to original sources
PubMed1992

Standards of practice in anaesthesia--intra-operative monitoring.

Intra-operative monitoring practice during anaesthesia was studied in a randomised selection of hospitals in different categories. Questionnaires from 45 anaesthetists in 20 hospitals provided information on 973 cases. The study showed that in 11% of cases the patient was left at some stage during anaesthesia without the attention of a medical practitioner and that in 7% of cases no record was made of the anaesthetic or of the parameters monitored. Types of monitoring varied considerably between hospitals and often fell short of acceptable minimal standards. Pulse oximetry, which is considered essential, was used in only 53% of cases. One in 18 cases was associated with a peri-operative critical incident and in 7 cases a critical incident occurred where the monitoring was deemed to be inadequate. Pulse oximetry would have assisted the anaesthetist in 6 of these 7 cases. In 3% of cases the anaesthetist admitted to fatigue during the procedure. This study highlights deficits in anaesthetic practice and in available equipment, both of which require urgent attention.

Anesthesia↗
PubMed1992

Early tracheal intubation with thiopentone in elective surgery.

We have studied tracheal intubating conditions within 30 s of administration of thiopentone in 24 patients and compared this with our usual method of tracheal intubation, which involves 3 min of manual ventilation in 29 patients. All patients received papaveretum 10 mg 3 min before induction and alcuronium at induction of anaesthesia. Satisfactory intubating conditions were observed in 83% of patients in both groups. There were no difficult or failed intubations and no patient had laryngospasm. The duration of laryngoscopy in the control group was 14.1 (SD 8.6) s (range 7-50 s), compared with 12.4 (3.1) s (range 6-20 s), in the early intubation group (ns). In the control group there was a significant decrease in systolic pressure before tracheal intubation and a significant increase in heart rate after intubation, compared with baseline values. The average systolic pressure in the early intubation group increased only minimally: from a pre-intubation value of 143.3 (21.2) mm Hg to 145.5 (25.1) mm Hg after intubation. Our results demonstrate that early tracheal intubation under thiopentone supplemented with an opioid and a non-depolarizing neuromuscular block is feasible, associated with minimal changes in arterial pressure and not accompanied by an increased incidence of side effects.

Adult↗
PubMed1992

Rapid administration of crystalloid preload does not decrease the incidence of hypotension after spinal anaesthesia for elective caesarean section.

Twenty parturients undergoing elective Caesarean section were allocated randomly to receive crystalloid preload 20 ml kg-1 over either 20 min or 10 min before spinal anaesthesia. Significant hypotension (systolic arterial pressure less than 100 mm Hg and less than 80% of baseline value) occurred in six of the 10 patients in the 20-min preload group and seven of 10 patients in the 10-min preload group (ns). Both groups had a significant (P less than 0.05) increase in central venous pressure during the preload period. The mean central venous pressure in the 10-min group was 11.9 mm Hg (range 6-19 mm Hg), which was significantly greater (P less than 0.05) than that in the 20-min group (mean 7.3 mm Hg, range 2-13 mm Hg). Three patients in the 10-min group had clinically unacceptable increases in central venous pressure. This study has demonstrated that rapid administration of crystalloid preload before spinal anaesthesia did not decrease the incidence or severity of hypotension, and questions the role of crystalloid preload.

Adult↗
PubMed1992

Thrombelastography after aspirin ingestion in pregnant and non-pregnant subjects.

The thrombelastograph (TEG) and bleeding time were performed before and 6 h after a single oral dose of aspirin 600 mg in a group of eight healthy volunteers and 12 pregnant patients. Measured TEG variables (r, k, r+k times and maximum amplitude) were unaltered after aspirin although there was a significant prolongation of the bleeding time in both groups. Although the TEG appeared not to detect aspirin-induced changes in platelet function, the TEG measures all phases of coagulation and the unaltered TEG after aspirin suggested a functioning coagulation system.

Aspirin↗
PubMed1992

Relative risk analysis of factors associated with difficult intubation in obstetric anesthesia.

Difficult tracheal intubation, often unexpected, has been identified as the commonest contributory factor to anesthetic-related maternal death. The ability to predict such cases preoperatively would be of great value. Preoperative airway assessment and potential risk factors for difficult tracheal intubation were recorded in 1,500 patients undergoing emergency and elective cesarean section under general anesthesia. Airway assessment using a modified Mallampati test recorded oropharyngeal structures visible upon maximal mouth opening. Potential risk factors documented were obesity; short neck; missing, protruding, or single maxillary incisors; receding mandible; facial edema; and swollen tongue. Subsequent to induction of anesthesia, the view at laryngoscopy and difficulty at intubation were graded. There was a significant (P less than 0.001) correlation between the oropharyngeal structures seen and both the veiw at laryngoscopy and difficulty at intubation. Univariate analysis demonstrated a significant association between difficult intubation and short neck (P less than 0.001), obesity (P less than 0.0001), missing maxillary incisors (P less than 0.02), protruding maxillary incisors (P less than 0.001), single maxillary incisor (P less than 0.0001), and receding mandible (P less than 0.003). Neither facial edema (P = 0.414) nor swollen tongue (P = 0.141) were found to be associated with difficult intubation. Multivariate analysis removed obesity and missing and single maxillary incisors as risk factors. Obesity was eliminated because of its strong association with short neck. The probability of experiencing a difficult intubation for various combinations of risk factors was determined.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Prophylactic intramuscular ephedrine prior to caesarean section.

Thirty healthy parturients, having given informed consent, were randomly allocated in a double-blind study to receive an intramuscular injection of either 0.9% sodium chloride (control), ephedrine 25 mg, or ephedrine 50 mg, 30 minutes prior to general anaesthesia for caesarean section. Nine patients (90%) in the 50 mg group and five patients (50%) in the 25 mg group demonstrated reactive hypertension of 20% or greater from control. The mean maximum increase in the 50 mg group was 28.2% (range 4.4-38.3%). Maternal pH was significantly lower (P = 0.03) in the ephedrine 50 mg group. Neonatal acid base status was significantly impaired in the ephedrine 50 mg group with umbilical venous pH (P = 0.0001) and umbilical arterial pH (P = 0.001) being significantly lower than the control group. The associated increase in umbilical arterial base deficit suggests a metabolic component due to fetal asphyxia related to decreased uterine blood flow. We conclude that the prophylactic administration of intramuscular ephedrine prior to spinal anaesthesia is associated with an unacceptably high incidence of maternal hypertension, and should the spinal fail and general anaesthesia be required, also results in adverse neonatal biochemical changes. The technique is therefore not to be recommended.

Adult↗
PubMed1990

Critical volume for pulmonary acid aspiration: reappraisal in a primate model.

We have studied, in the monkey, the critical volume for the production of severe pneumonitis following pulmonary aspiration of gastric contents. Aspiration of 0.4 ml kg-1 and 0.6 ml kg-1 at pH1 produced mild to moderate clinical and radiological changes, but no deaths. Aspiration of 0.8 ml kg-1 and 1.0 ml kg-1 at pH1 was associated with an increasingly severe pneumonitis. At 1.0 ml kg-1, 50% of the animals died--a mortality rate considerably less than that reported previously in animal studies. If these results were to be extrapolated to humans, the critical volume for severe aspiration could be increased from 25 ml to 50 ml (0.8 ml kg-1), considerably reducing the percentage of patients perceived to be "at risk".

Animals↗
PubMed1990

Effects of alfentanil and fentanyl on induction of anaesthesia in patients with severe pregnancy-induced hypertension.

Forty patients with severe pregnancy-induced hypertension presenting for Caesarean section under general anaesthesia were allocated randomly to receive either fentanyl 2.5 micrograms kg-1 or alfentanil 10 micrograms kg-1 as part of the anaesthetic induction sequence. In all patients, the cardiovascular response to tracheal intubation was measured. Both drugs attenuated the response equally but did not abolish it in all patients. Alfentanil 10 micrograms kg-1 is a suitable alternative to fentanyl 2.5 micrograms kg-1 for patients with pregnancy-induced hypertension.

Adult↗
PubMed1990

Prevention of hypotension following spinal anaesthesia for elective caesarean section by wrapping of the legs.

Twenty-four parturients undergoing elective Caesarean section were allocated randomly to have the legs wrapped with elasticated Esmarch bandages immediately following spinal anaesthesia or to serve as controls. Significant hypotension (systolic arterial pressure less than 100 mm Hg and less than 80% of baseline value) was treated with i.v. ephedrine in 5-mg boluses. Leg wrapped patients had a significantly (P = 0.0033) lower incidence (16.7%) of hypotension than controls (83.3%). Only two patients in the leg wrapped group required ephedrine compared with 10 in the control group. Systolic arterial pressure was significantly (P less than 0.05) less in control subjects at 4, 5 and 6 min following spinal injection. No patient in the leg wrapped group became hypotensive following removal of the elasticated bandages.

Anesthesia, Obstetrical↗
PubMed1988

Midazolam for induction of anaesthesia in patients with limited cardiac reserves. A comparison with etomidate.

The new water-soluble benzodiazepine, midazolam (Dormicum; Roche), was compared with etomidate as part of a balanced technique for induction of anaesthesia in 16 patients undergoing cardiac valve replacement. Monitoring revealed a significantly greater fall in blood pressure in patients receiving midazolam (reaching dangerous levels in 2 patients), which suggests that this agent is not suitable for induction of anaesthesia in haemodynamically compromised patients.

Adult↗
PubMed1988

Pneumonectomy in a patient with ventricular septal defect.

A young man with severe unilateral bronchiectasis and a ventricular septal defect presented for pneumonectomy. Intra-operative monitoring, which included continuous measurement of systemic and pulmonary oxygen saturations by oximetry, revealed transient reversal of the intracardiac shunt across the defect. The implications of this combination of cardiac and pulmonary disease for anaesthetic management are discussed.

Adult↗