Interchangeable oxygen and carbon dioxide in oxygen cylinders.
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Adult↗
Biomedical subjects
A N Thomas
Publications and source records attributed to A N Thomas.
Implementation of a tight glycaemic control protocol using a web-based insulin dose calculator.
We describe the implementation of a glucose control protocol supported by a web-based insulin dose calculator in a 16-bedded intensive care unit. The protocol was introduced and then modified after 15 months' use. Glucose concentrations were retrospectively reviewed and compared for the 9-month period before introduction of the protocol (288 patients), for 15 months after its introduction (502 patients) and for a further 5 months after its modification to increase insulin dose (101 patients). The mean (SD) blood glucose concentrations decreased from 7.3 (1.8) mmol.l(-1) to 6.6 (1.6) mmol.l(-1) and then to 6.2 (1.3) mmol.l(-1). The proportion of values < 8.0 mmol.l(-1) increased from 69% to 81% and then to 89%. Blood glucose concentrations were increased by the use of intravenous nutrition and by vasoactive drugs but not by the administration of propofol. The odds ratio [95% CI] for death for glucose values > 8.0 mmol.l(-1) was 2.10 [1.19-3.73] compared to values < 6.1 mmol.l(-1). However, patient mortality remained constant during the study. Glycaemic control was improved outside a research setting using a protocol supported by a web-based insulin dose calculator.
Adult↗
Use of a patient information system to audit the introduction of modified early warning scoring.
Modified early warning scoring (MEWS) uses abnormalities in routine observations to identify patients at risk of critical illness. Nurses recorded scores at or above the medical response score of 3 on a hospital clinical information system during the first year of introducing MEWS to 10 wards in a university hospital. A total of 619 triggers were recorded in 365 patients. Fifty-nine required intensive care unit (ICU)/high dependency unit (HDU) care; 71 died. Survival was significantly worse for initial scores >4 (35/104 patients died) than for scores 3-4 (P<0.004). Multivariant analysis showed age (P<0.001) and trigger score (P<0.001) but not ward specialty (P=0.1) predicted death. Mean ages of survivors and non-survivors were 64 years (SD 18) and 74 years (SD 17), respectively. Addition of a score for age did not significantly increase the area under a receiver operator characteristic curve for the predictive value of MEWS scores. The study shows that increasing MEWS score is associated with worse outcome across a range of specialties and that nursing staff will use a patient information system to audit MEWS scores.
Aged↗
Critical incident reporting in UK intensive care units: a postal survey.
RATIONALE, AIMS AND OBJECTIVES: To review critical incident reporting in UK intensive care units (ICUs). METHODS: We conducted a postal survey of clinical directors of UK ICUs to ask if critical incident reporting was used in their ICU. Using a structured questionnaire, we also asked for details of critical incident reporting systems and for changes introduced as a result of incident reporting. RESULTS AND CONCLUSIONS: Eighty-six of a total of 256 questionnaires were returned. Sixty-one units had been using a critical incident reporting system for a median duration of 3 years (interquartile range 2-5 years). There were wide variations in the structures of reporting systems between units. A median of four (interquartile range 3-8) critical incidents were reported per unit per month. In 141 changes, the development of protocols and guidelines (18) and changes in drug prescription and checking (20) were most common. A more consistent approach to reporting could improve patient care and 65 responders felt that a national reporting system was potentially useful.
Clinical Protocols↗
Interchangeable oxygen and air connectors.
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Air↗
Vasovagal syncope and anaesthetic practice.
We surveyed anaesthetists working in North-West England and in North Wales concerning episodes of vasovagal syncope encountered in their practice. Eighty-eight anaesthetists described 109 such events occurring in either patients or their relatives and the estimated frequency of syncope was 1 in 5000 anaesthetic episodes. The patient syncopal episodes were triggered by venous cannulation in 16 instances and regional or local techniques in 20 instances. Thirty-three of the 53 patients were in the upright position when syncope occurred. Thirty-nine of the 56 relatives were male partners of female patients and four of these partners suffered some morbidity. The results of the survey are consistent with our current knowledge of the pathophysiology of vasovagal syncope, which is summarized, and also highlight the common anaesthetic scenarios where fainting is most likely to occur. Given this information anaesthetists will be in a better position to avoid such potentially harmful episodes in the future.
Adult↗
Sarcoidosis presenting as an enlarging solitary pulmonary nodule.
Sarcoidosis is generally not considered in the differential diagnosis of solitary pulmonary nodules. We recently encountered a case in which preoperative awareness of this presentation of sarcoidosis allowed a limited pulmonary resection with resultant lower morbidity and potential preservation of lung function to be performed. Although rare, sarcoidosis should be considered in the differential diagnosis of solitary pulmonary nodules.
Diagnosis, Differential↗
Transfusion requirements during continuous veno-venous haemofiltration: -the importance of filter life.
OBJECTIVE: To investigate the relationship between loss of haemofilter circuits due to blood clots and requirement for blood transfusion in intensive care patients. DESIGN: Retrospective case note review. SETTING: A British, nine-bed, tertiary, medical and surgical intensive care unit (ICU) serving a 950-bed university teaching hospital. PATIENTS: Thirty-three ICU patients requiring haemofiltration for more than 48 h. Thirty-three comparison patients requiring 7 or more days of intensive care, without haemofiltration. METHODS: ICU, haemofiltration and haematology records were examined retrospectively. Note was taken of demographic data, daily haemoglobin concentrations and the dates and numbers of blood transfusions and haemofilter clots. RESULTS: The study groups did not differ significantly in terms of age, sex and length of ICU stay. Haemofiltered patients had higher APACHE II scores (21 vs 15, p = 0.006), lower haemoglobin concentrations (102 vs 110 g/l, p = 0.0001) and higher blood transfusion rates (1.1 vs 0.3 units/day, p < 0.0001) when compared to the non-haemofiltered group. There was a positive correlation between haemofilter blood clot rate and blood transfusion rate (r = 0.48). More blood was transfused on days when haemofilter blood clots occurred than on days when no haemofilter clot occurred (1.0 vs 0.59 units, p = 0.03). CONCLUSION: Haemofiltration is associated with an increased requirement for transfusion of blood. The temporal relationship between occurrence of haemofilter blood clots and transfusion of blood suggests that haemofilter lifespan may be an important determinant of this.
Blood Coagulation↗
The use of a blood conservation pressure transducer system in critically ill patients.
We tried to determine if a blood conservation pressure transducer system reduced blood transfusions, increased haemoglobin concentration or reduced line infections in critically ill patients. One hundred patients were randomly allocated to conventional or blood conserving systems attached to systemic and pulmonary arterial catheters. Intravascular lines were cultured after removal. There were no significant differences in transfusions or haemoglobin concentration. Blood conservation: median units transfused, 2 (range 0-19); mean haemoglobin at 7 days, 11.2 g.dl-1 (SD, 1.0). Conventional: median units, 2 (range 0-34); mean haemoglobin at 7 days, 11.1 g.dl-1 (SD 1.0). Thirty-seven of 99 arterial lines were colonised in the controls compared with 29 of 96 in the blood conservation group. Patients who required haemofiltration in both groups had significantly increased transfusion requirements. Haemofiltration: median 6 units (range 0-34) vs. non-haemofiltered: median 1 (range 0-14; p < 0.001). There were no significant differences in transfusions, haemoglobin concentration or line colonisation with the blood conservation system. There is considerable potential for blood conservation during haemofiltration.
Adult↗
Opiate withdrawal after tramadol and patient-controlled analgesia.
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Analgesia, Patient-Controlled↗
Diagnosis of pneumothorax in critically ill adults.
The diagnosis of pneumothorax is established from the patients' history, physical examination and, where possible, by radiological investigations. Adult respiratory distress syndrome, pneumonia, and trauma are important predictors of pneumothorax, as are various practical procedures including mechanical ventilation, central line insertion, and surgical procedures in the thorax, head, and neck and abdomen. Examination should include an inspection of the ventilator observations and chest drainage systems as well as the patient's cardiovascular and respiratory systems.Radiological diagnosis is normally confined to plain frontal radiographs in the critically ill patient, although lateral images and computed tomography are also important. Situations are described where an abnormal lucency or an apparent lung edge may be confused with a pneumothorax. These may arise from outside the thoracic cavity or from lung abnormalities or abdominal viscera inside the chest.
Adult↗
A comparison of standard and a modified method of two resuscitator adult cardiopulmonary resuscitation: description of a new system for research into advanced life support skills.
The study compares two methods of Advanced Life Support by a pair of resuscitators using a bag-valve-mask (BVM) technique. Standard two resuscitator cardiopulmonary resuscitation (CPR) was compared with a modified method of two resuscitator CPR. During the modified CPR one resuscitator held the face mask while the other resuscitator alternates between squeezing the self inflating bag and performing simulated cardiac compressions. Standard CPR was performed at a ventilation:compression ratio of 1:5 while modified CPR was performed at a ventilation:compression ratio of 2:15. Comparisons were made during induction of anaesthesia in 30 ASA I and II patients. Modified CPR produced a greater tidal volume (TV) (P < 0.001), a slower respiratory rate (RR) (P < 0.001) and a faster compression rate (CR) (P < 0.01) (means with (S.D.): modified CPR: TV 990 (220) ml, RR 6 (1) min(-1), CR 82 (8) min(-1); standard CPR: TV 570 (190) ml, RR 10 (2) min(-1), CR 65 (11) min(-1)). A new method for the simultaneous computerised recording of simulated cardiac compressions together with mask pressure and expired gas composition in anaesthetised patients is described.
Adult↗
A comparison of three methods of bag valve mask ventilation.
A method of bag valve mask ventilation in which the resuscitator compresses the self inflating bag between their open palm and the side of their body was compared with conventional single and two resuscitator bag valve mask ventilation. Fifteen nurses each ventilated three patients for 4 min following the induction of general anaesthesia, using one method per patient in random order. Tidal volume and peak mask pressures were higher with the two resuscitator technique than with either form of single resuscitator ventilation; There were no significant differences between the two methods of single resuscitator ventilation. Tidal volume: mean (S.D.); 'open palm': 270 ml (160); single resuscitator: 260 ml (220); two resuscitators: 480 ml (210). Peak mask pressure (mmHg): mean (SD); 'open palm': 19 (8); single resuscitator: 17(9); two resuscitator: 28 (11).
Adult↗
Comparison of lactate and bicarbonate buffered haemofiltration fluids: use in critically ill patients.
OBJECTIVE: To compare acid-base balance, lactate concentration, and haemodynamic and O2 transport variables during haemofiltration with replacement fluid containing 44.5 mmol/l Na+ lactate or 40 mmol/l Na+ HCO3- and 3 mmol/l lactic acid. DESIGN: A prospective, randomized trial. SETTING: A multidisciplinary, adult intensive care unit in a university hospital. PATIENTS: Forty acidotic patients who required haemofiltration, were dependent on mechanical ventilation, and had PA catheters in situ. INTERVENTIONS: During haemofiltration patients received lactate or bicarbonate replacement fluid at a mean rate of 1.7 l/h (SD 0.3). Arterial blood gases, plasma lactate, and haemodynamic and O2 transport variables were measured before and after 12 and 24 h haemofiltration. Ultrafiltrate was collected for lactate estimation. MEASUREMENTS AND MAIN RESULTS: As means (SD). The net gain of lactate was 63 mmol/h (12 mmol) with Na+ lactate and 0 mmol/h (0.3 mmol) with Na+ HCO3-. There was a significant increase in pH and [lactate] in both groups, but [lactate] was higher in patients receiving lactate. Twenty-one patients survived to ICU discharge, these patients were significantly less acidotic after filtration (lactate group: 0 h: pH 7.23 (0.09), [lactate] 2.4 mmol/l (1.7); 12 h: pH 7.34 (0.09), [lactate] 4.7 mmol/l (2.4); 24 h: pH 7.36 (0.07), [lactate] 4.7 mmol (2.7). HCO3 group: 0 h: pH 7.23 (0.09), [lactate] 2.3 (1.3); 12 h: pH 7.32 (0.06), [lactate] 2.9 mmol/l (1.8); 24 h: pH 7.35 (0.08), [lactate] 2.8 mmol/l (2.0). Base deficit: survivors: 0 h: 9 mmol/l (4); 12 h: 2 mmol/l (3). Non-survivors: 0 h: 10 mmol/l (3); 12 h: 6 mmol/l (3)). Haemodynamic and O2 transport variables were not significantly affected by treatment group or outcome. CONCLUSIONS: The degree of correction of acidosis during the first 24 h of haemofiltration was determined by patients outcome but was not affected by the substitution of bicarbonate- for lactate-containing replacement fluids.
Acidosis↗
Cardiopulmonary resuscitation: a retrospective review.
The outcome of patients admitted to intensive care after a cardiac arrest was determined by reviewing intensive care unit records at four hospitals for 1993 and 1994. Of the 112 patients identified, 49 survived intensive care of whom 28 were discharged from hospital. In January 1996, 26 of the 28 patients could be traced; 22 of these were still alive. Seven factors were significantly different between survivors and nonsurvivors. At the cardiac arrest these were the number of direct current shocks (p < 0.05) and adrenaline doses (p < 0.01) given. In intensive care the factors were the presence of reactive pupils (p < 0.01), Glasgow Coma Score (p < 0.001), APACHE II score (p < 0.05), arterial standard bicarbonate (p < 0.05) and the use of inotropes (p < 0.05). It was not possible to use individual variables to predict outcome at the time of intensive care unit admission. The results suggest that neurological function is an important determinant of outcome and more sensitive neurophysiological testing might be a useful prognostic tool.
Cardiopulmonary Resuscitation↗
The prognostic value of serial measurements of serum albumin concentration in patients admitted to an intensive care unit.
The prognostic value of serial measurements of serum albumin concentration during the first 72 h after admission to a general adult intensive care unit was retrospectively reviewed in 348 consecutive critically ill patients over a one year period. The accuracy of the admission APACHE II (Acute Physiology And Chronic Health Evaluation) score in correctly predicting patient outcome was compared with the serum albumin concentration measured at different times after intensive care unit admission. Multiple logistical regression analyses were performed to evaluate whether combining APACHE II and serum albumin into a unified risk index improved prognostic accuracy. Serum albumin concentration on admission was lower in non-survivors than in survivors and decreased more rapidly in non-survivors (p < 0.001). The admission serum albumin concentration was found to be an insensitive prognostic indicator. However, serum albumin measured after 24 h was as accurate as the admission APACHE II score in correctly classifying patients according to outcome. There was a good correlation between the admission APACHE II score and serum albumin measured after 24 h but not between the admission APACHE II and the admission serum albumin. Combining the APACHE II score and serial albumin concentrations into a unified risk of death equation did not improve the accuracy of outcome prediction.
APACHE↗
Creatinine and urea clearance during continuous veno-venous haemofiltration in critically ill patients.
Urea and creatinine clearances achieved using continuous veno-venous haemofiltration were calculated in 16 critically ill patients, during 50 episodes of filtration. The effects of filter life and the volume of ultrafiltrate on these clearances were also evaluated. Clearances were calculated from urea and creatinine concentrations in blood and ultrafiltrate and the volume of ultrafiltrate produced. The overall mean (SD) urea clearance was 26.6 (6.0) ml.min-1 and the overall creatinine clearance was 30.1 (6.3) ml.min-1. The mean (SD) ultrafiltrate production was 29.6 (5.9) ml.min-1. Creatinine clearance was significantly lower in filters that failed within 24 h (filters < 24 h 27.5 (6.3) ml.min-1; filters > 24 h 32.2 (5.5) ml.min-1). The clearance of both solutes increased with increasing ultrafiltrate volume (p < 0.001). We conclude that satisfactory clearance of urea and creatinine can be achieved using continuous veno-venous haemofiltration. Increases in ultrafiltrate production lead to similar increases in urea and creatinine clearance. Prolongation of filter life may improve creatinine clearance.
Acute Kidney Injury↗
Cross sensitivity between atracurium and mivacurium.
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Adult↗