T. E. Oh

Resuscitation of critically ill patients based on the results of gastric tonometry: a prospective, randomized, controlled trial.

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 μg/kg/min then 10 μg/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 ≥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.

Critical incident reporting in the intensive care unit

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.

Critical incident reporting in an anaesthetic department quality assurance programme

The critical incident technique was introduced as an additional form of quality assurance to an anaesthetic department of a major Hong Kong teaching hospital. In one year, 125 critical incidents were reported from over 16000 anaesthetics. The most common incidents reported concerned the airway, breathing systems, and drug administration, with inadequate checking of equipment a frequent associated factor. Human error was a factor in 80% of incidents. Critical incidents were reported for the time during which the patient was under the anaesthetists care. The majority occurred at induction or during anaesthesia, and were reported for all surgical subspecialties. Half of the incidents were detected by the anaesthetist and one third by monitoring equipment. Although there were improvements in anaesthetic care as a consequence of increased vigilance, critical incidents still occurred. Critical incident reporting highlighted problems not otherwise covered by case and peer reviews, and complemented our quality assurance programme.

Gastric emptying following brain injury: Effects of choice of sedation and intracranial pressure

ObjectiveTo compare the effects of opioid and nonopioid sedation on gastric emptying.DesignProspective, randomized trial.SettingUniversity teaching hospital ICU.Patients21 brain injured patients requiring sedation, mechanical ventilation and intracranial pressure (ICP) monitoring for >24h.InterventionsPatients were randomized to receive infusions of either morphine plus midazolam (M), or propofol (P). Gastric emptying was assessed by the paracetamol absorption technique and by residual volumes following a 200 ml test feed.measuerments and resultsPre-sedation Glasgow Coma Score, mean ICP and the presence of bowel sounds were noted. Plasma concentrations of paracetamol were measured over 3 h following a 1 g gastric dose. There were no differencese in median peak paracetamol concentration (M, 18.5 versus P, 20.8 mg/l), median time to peak concentration (M, 20 versus P, 25 min), median area under the concentration-time curve (AUC), or in the median residual volumes at 1 h (M, 14 versus P, 10.5 ml) and 2 h (M, 5 versus P, 3 ml). In patients with ICP>20 mmHg, paracetamol concentrations were lower (p<0.05), and AUC after 30 min was lower (165 mg·min/l versus 411 mg·min/l,p=0.023). Mean ICP was correlated with AUC (Kendall rankp=0.027). Gastric emptying did not correlate with initial Glasgow Coma Score or presence of bowel sounds.ConclusionsGastric emptying is not improved in patients with brain injury by avoiding morphine (1–8 mg/h) in the sedative regimen. Intracranial hypertension is associated with reduced gastric emptying.

Propofol for induction and maintenance of anaesthesia at Caesarean section A comparison with thiopentone/enflurane

A propofol infusion regimen and a standard general anaesthetic were compared in 40 Chinese women undergoing elective Caesarean section. Twenty patients received propofol 2 mg/kg for induction of anaesthesia followed by propofol 6 mg/kg/hour, while 20 patients received thiopentone 4 mg/kg with enflurane 1% for maintenance of anaesthesia. All patients were given atracurium and their lungs ventilated with nitrous oxide 50% in oxygen until delivery of the neonate. The hypertensive response after intubation was of shorter duration in the propofol group compared with the thiopentone group. Induction to delivery times ranged from 5 to 14 minutes and neonates from both groups had similar and satisfactory Apgar scores, Neurologic and Adaptive Capacity Scores and umbilical cord blood gas analysis. However, a prolonged propofol infusion time before delivery may cause lower Neurologic and Adaptive Capacity Scores. There were no differences in maternal recovery times or psychomotor performance.

Improvements in anaesthetic care resulting from a critical incident reporting programme

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.

A comparison of the effects of omeprazole and ranitidine on gastric secretion in women undergoing elective caesarean section.

This study compares the efficacy of omeprazole and ranitidine at reducing gastric secretion in obstetric patients. Sixty‐five women scheduled to undergo elective Caesarean section under general anaesthesia were randomly allocated to receive either omeprazole 40 mg or ranitidine 150 mg orally at 2200 hours the night before and at 0600 hours on the morning of surgery. Intragastric pH and volume were measured immediately after induction of anaesthesia and on completion of surgery. All patients had gastric aspirates less than 25 ml. None of the omeprazole group had an aspirate of pH less than 3.5. Six patients (19%) in the ranitidine group had aspirates of pH less than 3.5, a significant difference from the omeprazole group (p < 0.05). Of these six, two (6%) had aspirates of pH less than 2.5. Hence this study showed that omeprazole was more effective and consistent than ranitidine at maintaining gastric pH greater than 3.5.

Oxygen therapy for hypercapnic patients with chronic obstructive pulmonary disease and acute respiratory failure: a randomized, controlled pilot study.

Objective To investigate the effect of oxygen therapy on outcome and on symptomatic hypercapnia. Design Randomized, controlled, single-blind study. Setting Multidisciplinary intensive care unit of a university teaching hospital. Patients Patients admitted with a clinical diagnosis of an acute exacerbation of chronic obstructive pulmonary disease and a Pao2 <6.6 kPa (50 mm Hg) and Paco2 >6.6 kPa (50 mm Hg) on air. Interventions Patients received oxygen therapy titrated to increase arterial oxygen tension to >6.6 kPa (50 mm Hg) or >9 kPa (70 mm Hg). Patients in the low-oxygen tension group also received doxapram if they developed an acidosis with pH <7.2, whereas those in the high-oxygen tension group received doxapram if they developed symptomatic acidosis. Bronchodilator, steroid, and antibiotic therapy was standardized. Measurements and Main Results Two patients in the low-oxygen tension group (n = 17) required mechanical ventilation and another one died. No patients in the high-oxygen group (n = 17) had a poor outcome, but this difference was not significant. No patient in either group became comatose or developed an acute cardiac arrhythmia. Conclusions Traditional teaching related to oxygen therapy for hypercapnic patients with an acute exacerbation of chronic obstructive pulmonary disease may be incorrect. A large randomized, controlled study is required to confirm this impression.

Resistance and additional inspiratory work imposed by the laryngeal mask airway. A comparison with tracheal tubes

Laryngeal mask airways and tracheal tubes were studied to determine both their resistance to constant gas flows and additional inspiratory work during simulated inspiration. Laryngeal mask airways imposed less resistance and required lower additional inspiratory work compared with the corresponding sized tracheal tubes. If inspiratory loading during anaesthesia is an important consideration, then the laryngeal mask airway may be preferable to a tracheal tube.

A comparison of omeprazole and ranitidine for prophylaxis against aspiration pneumonitis in emergency Caesarean section

One hundred and sixty‐two Chinese women undergoing emergency Caesarean section were allocated at random on admission to the labour ward to receive one of three regimens for orally administered chemoprophylaxis against acid aspiration: ranitidine 150 mg 6 hourly with sodium citrate at induction of anaesthesia, omeprazole 40 mg 12 hourly with sodium citrate, or omeprazole 40 mg 12 hourly alone. Intragastric pH and volume were measured immediately after induction of anaesthesia. Ten patients (17%) in the omeprazole‐only group, three (6%) in the omeprazole and citrate group and one (2%) in the ranitidine group had an intragastric pH < 2.5 and volume > 25 ml (p < 0.05). The use of sodium citrate resulted in higher intragastric pH but larger intragastric volumes (p < 0.05). The sodium citrate and ranitidine regimen was the most cost‐effective among the three.