Biomedical subjects
Publications and source records attributed to T A Buckley.
A 41-year-old woman presented with the clinical features of methaemoglobinaemia after drinking Chinese herbal medicine. A life threatening methaemoglobin level of 68% was measured. Both clinical and laboratory diagnostic difficulties were encountered. The pitfalls of pulse oximeter, blood gas analysis and co-oximeter interpretation during diagnosis and after methylene blue administration are discussed.
In this study we aimed to examine the association between serum albumin concentration and mortality risk in critically ill patients. We retrospectively studied 1003 patients admitted to ourIntensive Care Unit (ICU) over an 18-month period. Serial albumin measurements over 72 hours were compared between survivors and non-survivors, and medical and surgical patients were also compared. Our results showed that serum albumin decreased after ICU admission, most rapidly in the first 24 hours, in both survivors and non-survivors. Serum albumin was lower in non-survivors than in survivors, but albumin concentrations poorly differentiated the two groups. Medical patients had higher admission albumin levels than surgical patients, but both subgroups showed a similar albumin profile over 72 hours. We evaluated the prognostic value of serum albumin using receiver operator characteristic (ROC) curves. We constructed ROC curves for APACHE II score, admission albumin, albumin at 24 and 48 hours. We also combined APACHE II with albumin values and constructed the corresponding ROC curves. Our data showed that serum albumin had low sensitivity and specificity for predicting hospital mortality. Combining APACHE II score with serum albumin concentrations did not improve the accuracy of outcome prediction over that of APACHE II alone.
Eighteen cases of human influenza A H5N1 infection were identified in Hong Kong from May to December 1997. Two of the six fatal cases had undergone a full post-mortem which showed reactive hemophagocytic syndrome as the most prominent feature. Other findings included organizing diffuse alveolar damage with interstitial fibrosis, extensive hepatic central lobular necrosis, acute renal tubular necrosis and lymphoid depletion. Elevation of soluble interleukin-2 receptor, interleukin-6 and interferon-gamma was demonstrated in both patients, whereas secondary bacterial pneumonia was not observed. Virus detection using isolation, reverse transcription-polymerase chain reaction and immunostaining were all negative. It is postulated that in fatal human infections with this avian subtype, initial virus replication in the respiratory tract triggers hypercytokinemia complicated by the reactive hemophagocytic syndrome. These findings suggest that the pathogenesis of influenza A H5N1 infection might be different from that of the usual human subtypes H1-H3.
INTRODUCTION: Patients admitted to the intensive care unit (ICU) may not benefit from the life support provided and it may result in prolonged and unnecessary suffering. Limiting life-support therapy in this situation is an ethically acceptable practice in Western countries. Statements produced by professional bodies have been generally made from a Western perspective. Cultural influences, aspects of management and resource limitations may create differences, yet there is little information available on the ethical decision making processes involved in limitation of life support in Asian countries. This article reviews the processes involved in the limitation of life support in critically ill intensive care patients in the predominantly Chinese population of Hong Kong. METHODS: Direct and computerised search of locally available and international published research articles and opinions. RESULTS: Limitation of life-support therapy occurs in 23% to 61% of critically ill Chinese patients that die within the ICU which is comparable to figures presented in the Western literature. Relatives wish to be part of the decision making process when limitation of therapy is to be considered. A staff attitude of caring towards patient and family, a need for information from the doctor and staff, and competence in providing adequate treatment have been identified as important factors by relatives when limitation of life-support therapy was being discussed. CONCLUSIONS: Limitation of therapy in dying Chinese patients occurs in ICUs and, patients and relatives concur in 95% of cases with medical decisions to limit therapy in these patients. The importance of communication as well as a desire to participate in the decision-making process regarding limitation of therapy suggest similarities between Western and Asian expectations. More comprehensive data are required regarding end-of-life issues in the Asian context, especially in relation to the general population's perception as to the processes involved.
INTRODUCTION: Traditionally, outcome from intensive care has focused on mortality. The cost of intensive care and the limited resources devoted to patients who have a poor prognosis also raises questions about the utilisation of such resources. There is increasing pressure for outcome evaluation of intensive care to incorporate assessment of long-term survival and the quality of life in survivors. The principal objectives of this article were to examine current methods of assessing quality of life measures in critically ill patients surviving intensive care and to determine the quality of life of these survivors. METHODS: Direct and computerised search of published research articles. RESULTS: Measurement of quality of life after intensive care is not common practice. There is a lack of consensus concerning appropriate measuring instruments to be used and how best to interpret results. Despite the availability of general outcome tools and disease specific instruments, there is a paucity of studies in the literature which include assessments of quality of life following intensive care unit (ICU) care. Generic health indices suggest that the quality of life in ICU survivors is acceptable though in certain sub-groups, e.g. adult respiratory distress syndrome and sepsis, quality of life may be moderately impaired. ICU survivors appear to suffer less disability than chronic physical disease patients. CONCLUSIONS: Assessment of outcome after intensive care should include health related quality of life measurements. A unifying framework is required to enhance communication between clinicians, administrators and investigators of quality of life research and also to enable more rational and effective decision making at the bedside. Patients who survive intensive care appear to enjoy a reasonable standard of quality of life. While their health status may not be as good, subjectively patients find this acceptable.
INTRODUCTION: Intra-abdominal hypertension is becoming increasingly recognised in intensive care patients. The objective of this paper was to review the modern published literature to establish a representative consensus view of the incidence, causes, pathophysiology, management and outcome of intra-abdominal hypertension. METHODS: A computerised MEDLINE search from 1966 to November 2000 was conducted using the Medical Subject Heading and textwords "abdominal", "compartment syndromes", "intra-abdominal" and "hypertension" and "pressure". The references of recent articles were checked for additional relevant citations. Papers were independently assessed for relevance by authors SJR and GMJ using a data collection format. Data were assessed qualitatively and papers detailing physiologic variables, effects of decompression and outcome were abstracted in table form. CONCLUSIONS: Intra-abdominal hypertension exists when intra-abdominal pressure exceeds 10 to 12 mmHg as physiological aberrations are manifest above this pressure. Incidence is 5% to 40% in high-risk surgical patients. Pathophysiological changes caused by intra-abdominal hypertension include effects on the gastrointestinal, cardiovascular, renal, respiratory and central nervous systems. An association between intra-abdominal hypertension and subsequent multiple organ failure has been repeatedly shown, although causation remains unproven. Monitoring intra-abdominal pressure (IAP) by measuring urinary bladder pressure is easy and accurate. However, it is unclear what level of intra-abdominal pressure requires intervention (decompression), or what length of time intra-abdominal hypertension can be tolerated before significant end organ damage occurs. In the absence of good outcome data, expert consensus is that an acute increase of IAP to above 20 to 25 mmHg and/or evidence of abdominal compartment syndrome warrants urgent decompression. While some progress has been made in describing and managing this clinical entity, further studies are needed to fully understand the clinical implications and confirm appropriate management of this condition.
OBJECTIVE: To determine whether additional therapy aimed at correcting low gastric intramucosal pH (pHi) improves outcome in conventionally resuscitated, critically ill patients. DESIGN: Prospective, randomized, controlled study. SETTING: General intensive care unit (ICU) of a university teaching hospital. PATIENTS: A total of 210 adult patients, with a median Acute Physiology and Chronic Health Evaluation II score of 24 (range, 8-51). INTERVENTIONS: All patients were resuscitated according to standard guidelines. After resuscitation, those patients in the intervention group with a pHi of <7.35 were treated with additional colloid and then dobutamine (5 microg/kg/min then 10 microg/kg min) until 24 hrs after enrollment. MEASUREMENTS AND MAIN RESULTS: There were no significant differences (p > .05) in ICU mortality (39.6% in the control group vs. 38.5% in the intervention group), hospital mortality (45.3% in the control group vs. 42.3% in the intervention group), and 30-day mortality (43.7% in the control group vs. 40.2 in the intervention group); survival curves; median modified maximal multiorgan dysfunction score (10 points in the control group vs. 13 points in the intervention group); median modified duration of ICU stay (12 days in the control group vs. 11.5 days in the intervention group); or median modified duration of hospital stay (60 days in the control group vs. 42 days in the intervention group). A subgroup analysis of those patients with gastric mucosal pH of > or =7.35 at admission revealed no difference in ICU mortality (10.3% in the control group vs. 14.8% in the intervention group), hospital mortality (13.8% in the control group vs. 29.6% in the intervention group), or 30-day mortality (10.3% in the control group vs. 26.9% in the intervention group). CONCLUSIONS: The routine use of treatment titrated against pHi in the management of critically ill patients cannot be supported. Failure to improve outcome may be caused by an inability to produce a clinically significant change in pHi or because pHi is simply a marker of disease rather than a factor in the pathogenesis of multiorgan failure.
A 3-year-old boy presented with brainstem astrocytoma and central alveolar hypoventilation syndrome. Contrast MRI of the brain showed that the tumor involved the cerebellum, with compression of brainstem, and resolved after surgical resection. Polysomnography performed before and after total tumor resection showed significant improvement in nocturnal respiratory rate, respiratory disturbance index, and oxygen desaturation. It is apparent that central alveolar hypoventilation syndrome secondary to brainstem tumor may improve after surgical resection for those with favorable anatomic location and histology. Serial polysomnography and MRI scans are useful for diagnosis and in the management plan, and to monitor progress.
OBJECTIVE: To review the factors involved in determining the availability of solid organs for transplantation in Hong Kong and to identify methods that have been used in other countries to increase organ donation rates. DATA SOURCES: Medline and non-Medline search of the relevant English literature, local data, and personal experience. STUDY SELECTION: Articles describing approaches to solid organ procurement for transplantation. DATA EXTRACTION: Data were extracted and analysed by the author. DATA SYNTHESIS: There is a severe shortage of solid organ donors in Hong Kong, which is compounded by an ever-increasing pool of potential recipients. Limited local data suggest public support for organ donation. The most common reason for objection to organ donation is a lack of knowledge of the wishes of the deceased. Despite the implementation of numerous legislative models worldwide, none has been shown to be superior as a facilitator of organ donation. Despite the lack of legislation in Hong Kong, the medical profession has adopted the expressed consent model. The use of non-heart-beating donors, elective ventilation of futile cases, and financial incentives pose significant ethical and legal barriers as well as resource implications for intensive care. CONCLUSION: Greater effort should be directed through public education at the importance of telling one's family what one's wishes are concerning organ donation. More information is required in Hong Kong as to why families agree to organ donation and how best to approach families to request organ donation.
OBJECTIVES: To assess mortality and functional health status of patients at 1 yr following admission to a multidisciplinary intensive care unit (ICU) in Hong Kong. To determine which factors are associated with a poor long-term outcome. DESIGN: Prospective data collection and review. SETTING: A 14-bed multidisciplinary ICU in a 1,400-bed tertiary care university hospital. PATIENTS: Data from 2,268 consecutive patients admitted over a 2.5-yr period was analyzed, including follow-up at 1 yr in 853 adult survivors. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The patients' clinical details and Acute Physiology and Chronic Health Evaluation (APACHE) II scores were recorded on day 2 of admission and reviewed at time of discharge or death. The mean APACHE II score on admission was 18. Survival status at 1 yr was ascertained and the sickness impact profile (SIP) scored as a measure of functional health status for survivors. Sixty-five percent of patients survived to discharge from hospital and 44% of patients were known to survive to 1 yr; 6% of patients could not be traced at 1 yr. Functional health status was assessed in 85% of eligible adult patients. Survivors to 1 yr were younger than nonsurvivors and had lower APACHE II scores. The median SIP score was 5.1, (25th and 75th percentiles: 0 to 15), and 76% of patients had SIP scores < or = 15, i.e., normal health to moderate disability. Five percent of the patients were not working or had retired for health-related reasons. Stepwise logistic regression to identify factors associated with poor functional health status defined as a SIP score >15 at 1 yr found increasing age, cardiac/ respiratory arrest, intracranial hemorrhage, and trauma to be associated with poor outcomes. A correlation was found between APACHE II scores and SIP scores (Spearman's correlation coefficient = 0.13, p < .001). CONCLUSIONS: The SIP scores indicated that the majority of patients who survived to 1 yr after ICU admission enjoyed reasonable functional health status. A poor functional health status at 1 yr did not relate to the severity of the acute illness suffered, but appeared to relate to the prognosis of the underlying disease process.
Because of the lack of suitable generic health status measures in Hong Kong that reflect the value structure and culture of the society, we have translated and calibrated the Sickness Impact Profile, which was originally developed in the United States. Translation consisted of a sequence of forward translations into Chinese, back translations into English and, when there was a loss of meaning or conceptual equivalence, retranslation into Chinese. Sixty Hong Kong Chinese people, including health professionals, patients, and members of the public were then recruited to determine item and dimension weights for the Hong Kong population. Individual ratings were averaged to obtain a consensus value for each item. Within-category reliability analysis for scores varied from 0.70 to 0.92 (Cronbach's alpha values) and overall internal consistency was 0.98. There were only small differences between this version and the original American English version in the ratings given to individual questions (Pearson's product moment correlation coefficient, r=0.8). We have developed a Chinese translation of the Sickness Impact Profile, which can now be used to evaluate health outcomes in Hong Kong and to compare outcomes with studies in other populations where the Sickness Impact Profile was used.
Critical incident reporting was introduced into the intensive care unit (ICU) as part of the development of a quality assurance programme within our department. Over a 3-year period 281 critical incidents were reported. Factors relating to causation, detection and prevention of critical incidents were sought. Detection of a critical incident in over 50% of cases resulted from direct observation of the patient while monitoring systems accounted for a further 27%. No physiological changes were observed in 54% of critical incidents. The most common incidents reported concerned airway management and invasive lines, tubes and drains. Human error was a factor in 55% of incidents while violations of standard practice contributed to 28%. Critical incident reporting was effective in revealing latent errors in our "system' and clarifying the role of human error in the generation of incidents. It has proven to be a useful technique to highlight problems previously undetected in our quality assurance programme. Improvements in quality of care following implementation of preventative strategies await further assessment.
Splanchnic ischaemia is thought to be of central importance in the development of multi-organ failure and hence death in critically ill patients. It has been suggested that the arterial to gastric intramucosal pH gradient and the difference in partial pressure of carbon dioxide between gastric mucosa and arterial blood are more sensitive markers of splanchnic ischaemia than gastric intramucosal pH itself and thus should be predictors of mortality in the critically ill. We studied 62 critically ill patients within 6 h of admission to the intensive care unit and found no significant difference at 0, 12 or 24 h after admission to the study in either the arterial to gastric intramucosal pH gradient or the difference in partial pressure of carbon dioxide between gastric mucosa and arterial blood between survivors and nonsurvivors. We conclude that in contrast to gastric intramucosal pH neither the arterial to gastric intramucosal pH gradient nor the difference in partial pressure of carbon dioxide between gastric mucosa and arterial blood distinguish survivors from nonsurvivors.
BACKGROUND: Complications can arise from standard intrathoracic central venous pressure (CVP) measurements in critically ill, mechanically ventilated patients. We have assessed the feasibility of catheterisation by the femoral route to measure CVP in the abdomen (ACVP). We compared measurements by the standard jugular or subclavian route (TCVP) with simultaneous ACVP measurements by the femoral route. METHODS: Between June, 1994 and May, 1995, we recruited 20 critically ill adult patients with various disorders; all patients already had a TCVP line in situ. We placed a femoral catheter in the inferior vena cava close to the right atrium under electrocardiographic guidance. The catheter position was confirmed (and corrected if necessary) by chest radiography. CVP was measured from both sites hourly for 6 h. Positive end-expiratory pressure, mean airway pressure, and intra-abdominal pressure were recorded simultaneously. FINDINGS: One patient was excluded because radiography showed that the catheter position was incorrect. For 133 paired measurements of ACVP and TCVP in the remaining 19 patients, the mean difference was 0.45 mm Hg (SD 0.89: 95% Cl 0.30-0.60); the limits of agreement were -1.33 to 2.23 mm Hg (-1.63 to 2.53). We found a small tendency for the difference between ACVP and TCVP to increase as positive end-expiratory pressure and mean airway pressure increased; the difference was statistically, but not clinically, significant. INTERPRETATION: Our study showed that for clinical purposes CVP can be measured by a femoral catheter placed in the abdominal inferior vena cava near the right atrium. This approach can replace standard TCVP measurements in critically ill, mechanically ventilated patients.
The rôle of an anaesthetic incident reporting programme in improving anaesthetic safety was studied. The programme had been running for 4 to 5 years in three large hospitals in Hong Kong and more than 1000 incidents have been reported. The number of reports being made and frequency of the various categories of incident reported, did not alter during the study period. Sixty nine percent of incidents were considered to be preventable. Human error contributed to 76% of incidents and violations of standard practice to 30% of incidents. The programme was effective in its ability to detect latent errors in the anaesthesia system and when these were corrected, incidents did not recur. The frequency with which various contributing factors were cited did not decrease with time. With the exception of problems dealt with by specific protocol development, the study found no evidence that an increasing awareness of the problem of human error was effective in reducing this kind of problem.
OBJECTIVE: To compare the superimposed inspired work of breathing (SIW) of the Siemens Servo 300 ventilator with the Siemens Servo 900 C ventilator. DESIGN: Comparisons made at continuous positive airway pressure (CPAP) levels of 0, 4, and 8 cmH2O, and at trigger sensitivities of -1 and -2 cmH2O, and flow triggering. SETTING: General intensive care unit in a University teaching hospital. PATIENTS: 7 patients receiving CPAP. At all levels of CPAP, the SIW was significantly less with the Siemens Servo 300 ventilator as compared to the Siemens Servo 900 C ventilator despite similar trigger sensitivities. No significant difference was found in the SIW of the Servo 300 ventilator when comparing trigger sensitivities of -1 cmH2O, -2 cmH2O, and flow triggering. Different levels of CPAP had no effect on SIW. CONCLUSIONS: The Siemens Servo 300 ventilator entails less superimposed inspiratory work of breathing than the Siemens Servo 900 C ventilator.
We investigated the accuracy of recycled gastric tonometer catheters, using a prospective laboratory model, within the Intensive Care Unit of a University teaching hospital. Ten used tonometer catheters and three new catheters were exposed to known constant PCO2 levels between 23-65 torr (3.06-8.66 kPa) in a gas mixing chamber, at a temperature of 35.5-38 degrees C and a relative humidity > 95%. The tonometer balloons were primed with normal saline, and after a 30-minute equilibration time, the saline was sampled for PCO2 measurements. Steady-state PCO2 (PCO2(SS)) and gastric mucosal pH (pHi) values were derived using a correction factor and the Henderson-Hasselbalch equation. There was no difference in the mean or distribution of PCO2(SS) values between recycled and new catheters. The PCO2(SS) values of recycled catheters were within the 95% confidence limits of those of new catheters. Individual catheter values did not differ significantly from each other (ANOVA P = 0.05). Using an arterial HCO3- value of 21 mmol/l, the calculated pHi values of used catheters varied < 1.5% of the mean pHi of new catheters. The tonometric performance of recycled gastric tonometer catheters was similar to that of new catheters when tested in vitro.