Unexpected cardiac arrest among children during surgery, a North American registry to elucidate the incidence and causes of anesthesia related cardiac arrest.

Relatively rare adverse events, such as unexpected cardiac arrest, are difficult to study in the clinical setting. These events are often unpredictable in their occurrence (prompting interest in their investigation) and do not occur with sufficient frequency in any single institution to provide an adequate sample for analysis. A disease-specific registry is an epidemiological technique that can be used to collect data on a set of relatively rare unpredictable events. This approach was adopted for investigation of cardiac arrest in children when it became apparent from analysis of malpractice claims that a significant clinical problem existed. This report provides a brief historical account of the development of the Pediatric Peri-Operative Cardiac Arrest (POCA) Registry and elaborates on the methodology including strengths, weaknesses, and practical implementation issues.

Anesthesia-related cardiac arrest in children: initial findings of the Pediatric Perioperative Cardiac Arrest (POCA) Registry.

BACKGROUND: The Pediatric Perioperative Cardiac Arrest (POCA) Registry was formed in 1994 in an attempt to determine the clinical factors and outcomes associated with cardiac arrest in anesthetized children. METHODS: Institutions that provide anesthesia for children are voluntarily enrolled in the POCA Registry. A representative from each institution provides annual institutional demographic information and submits anonymously a standardized data form for each cardiac arrest (defined as the need for chest compressions or as death) in anesthetized children 18 yr of age or younger. Causes and factors associated with cardiac arrest are analyzed. RESULTS: In the first 4 yr of the POCA Registry, 63 institutions enrolled and submitted 289 cases of cardiac arrest. Of these, 150 arrests were judged to be related to anesthesia. Cardiac arrest related to anesthesia had an incidence of 1.4 +/- 0.45 (mean +/- SD) per 10,000 instances of anesthesia and a mortality rate of 26%. Medication-related (37%) and cardiovascular (32%) causes of cardiac arrest were most common, together accounting for 69% of all arrests. Cardiovascular depression from halothane, alone or in combination with other drugs, was responsible for two thirds of all medication-related arrests. Thirty-three percent of the patients were American Society of Anesthesiologists physical status 1-2; in this group, 64% of arrests were medication-related, compared with 23% in American Society of Anesthesiologists physical status 3-5 patients (P < 0.01). Infants younger than 1 yr of age accounted for 55% of all anesthesia-related arrests. Multivariate analysis demonstrated two predictors of mortality: American Society of Anesthesiologists physical status 3-5 (odds ratio, 12.99; 95% confidence interval, 2.9-57.7), and emergency status (odds ratio, 3. 88; 95% confidence interval, 1.6-9.6). CONCLUSIONS: Anesthesia-related cardiac arrest occurred most often in patients younger than 1 yr of age and in patients with severe underlying disease. Patients in the latter group, as well as patients having emergency surgery, were most likely to have a fatal outcome. The identification of medication-related problems as the most frequent cause of anesthesia-related cardiac arrest has important implications for preventive strategies.

The hemodynamic effects of propofol in children with congenital heart disease.

UNLABELLED: We studied the hemodynamic effects of propofol during elective cardiac catheterization in 30 children with congenital heart disease. Sixteen patients were without cardiac shunt (Group I), six had left-to-right cardiac shunt (Group II), and eight had right-to-left cardiac shunt (Group III). The mean (+/-SD) ages were 3.8+/-3.1 yr (Group I), 3.2+/-3.7 yr (Group II), and 1.0+/-0.6 yr (Group III). After sedation and cardiac catheter insertion, hemodynamic data and oxygen consumption were measured before and after the administration of propofol (2-mg/kg bolus, 50- to 200-microg x kg(-1) x min(-1) infusion), and values were compared by using a paired t-test (significance: P < 0.05). After the propofol administration, systemic mean arterial pressure and systemic vascular resistance decreased significantly and systemic blood flow increased significantly in all patient groups; heart rate, pulmonary mean arterial pressure, and pulmonary vascular resistance were unchanged. Pulmonary to systemic resistance ratio increased (Group I, P = 0.005; Group II, P = 0.03; Group III, P = 0.10). In patients with cardiac shunt, propofol resulted in decreased left-to-right flow and increased right-to-left flow; the pulmonary to systemic flow ratio decreased significantly (Group II, P = 0.005; Group III, P = 0.01). Clinically relevant decreases in Pao2 (P = 0.008) and Sao2 (P = 0.01) occurred in Group III patients. We conclude that propofol can result in clinically important changes in cardiac shunt direction and flow. IMPLICATIONS: The principal hemodynamic effect of propofol in children with congenital heart defects is a decrease in systemic vascular resistance. In children with cardiac shunt, this results in a decrease in the ratio of pulmonary to systemic blood flow, and it can lead to arterial desaturation in patients with cyanotic heart disease.

Guidelines for the pediatric perioperative anesthesia environment. American Academy of Pediatrics. Section on Anesthesiology.

The American Academy of Pediatrics proposes the following guidelines for the pediatric perioperative anesthesia environment. Essential components are identified that make the perioperative environment satisfactory for the anesthesia care of infants and children. Such an environment promotes the safety and wellbeing of infants and children by reducing the risk for adverse events.

Multi-institutional survey of graduates of pediatric anesthesia fellowship: assessment of training and current professional activities.

UNLABELLED: We surveyed all the graduates of four fellowship programs in pediatric anesthesia between 1985 and 1993 to assess their current professional activities, their evaluation of fellowship training, and their opinions on future directions of such training. One-hundred ninety-one (62%) of the graduates responded. Nearly all of the respondents had sought fellowship training for pediatric anesthesia and thought that the training was worthwhile. At the time of the survey, 40% worked in a children's hospital, 72% had university or affiliate positions, and 54% had a practice that was > 50% pediatric. Those with > or = 12 mo fellowship and/or board certification in pediatrics were the most likely to have a pediatric-dedicated practice. Seventy percent of the respondents thought that fellowship training should be for 12 mo, and the proportion of respondents who recommended inclusion of training in pain management and clinical research was greater than the number who had actually received such training. Fifty-eight percent of respondents supported restriction of fellowship positions in the future, but 83% did not support a mandatory 2-yr fellowship with research training. We conclude that fellowships in pediatric anesthesia seem to be successful in providing training that is not only satisfying to the trainees, but that is also followed by active involvement in the care of children and in the training of residents and fellows in anesthesia. Additional information should be gathered to assess the impact of this training on pediatric care, to formulate a standardized curriculum, and to justify support for such training in the future. IMPLICATIONS: We surveyed graduates of four fellowship programs in pediatric anesthesia (1985-1993) to assess current professional activities, fellowship training, and future directions of such training. Fellowships in pediatric anesthesia seem to provide training that is satisfying to trainees and that is followed by active involvement in the care of children.

The effect of halothane on phrenic and chemoreceptor responses to hypoxia in anesthetized kittens.

We examined the effect of halothane on phrenic never and carotid sinus discharge during hypoxia in anesthetized kittens. In 12 animals, phrenic amplitude was measured during normoxia, during isocapnic hypoxia, and after a return to normoxia, both with and without halothane. Without halothane, all animals had an increase in phrenic amplitude during hypoxia. With halothane, half the animals showed an increase in phrenic amplitude followed by a decline. In a second group of animals, recordings were obtained from single or a few fiber strands of carotid sinus nerve. Without halothane, an increase in chemoreceptor discharge frequency during hypoxia was seen. With 1.0% halothane, frequency was decreased during normoxia and did not increase during hypoxia. Thus, halothane's effect on the ventilatory response to hypoxia, as measured by phrenic discharge, is at least partially explained by an effect on peripheral chemoreceptors.

Use of cardiopulmonary bypass during bronchoscopy following sand aspiration. A case report.

A 6-year-old boy with massive sand aspiration was effectively treated with femoral vein to femoral artery cardiopulmonary bypass (CPB), saline bronchial lavage, and exogenous surfactant. The patient was discharged the 9th hospital day without apparent sequelae. CPB should be considered for cases of sand or gravel aspiration when gas exchange is compromised.

Serial neurologic examinations after near drowning and outcome.

OBJECTIVE: We evaluated serial neurologic examinations after warm water near drowning to determine how rapidly survivors with poor neurologic outcome could be identified. RESEARCH DESIGN: Retrospective chart review. SETTING: University-affiliated pediatric hospital. PATIENTS: Forty-four children admitted to the pediatric intensive care unit with an abnormal mental status after near drowning during a 5-year period. Follow-up was a minimum of 6 months. INTERVENTIONS: None. MEASUREMENTS: A 14-point coma scale was used to evaluate both cortical and brain-stem function at the time of hospital admission and then daily afterward. The Mann-Whitney U Test was used to compare patients grouped as having satisfactory outcomes (those who returned to their presubmersion baseline or had very mild deficits) and unsatisfactory outcomes (total custodial care or death). Significance was defined as P < .05. CONCLUSION: All satisfactory survivors were sufficiently awake to have spontaneous, purposeful movements 24 hours after near drowning and had normal brain-stem function. All children without spontaneous, purposeful movements and normal brain-stem function 24 hours after near drowning suffered severe neurologic deficits or death. In this retrospective investigation of 44 children, the cortical examination 24 hours after warm water near drowning distinguished satisfactory survivors from children who required total custodial care or died.

A comparison of pediatric and adult anesthesia closed malpractice claims.

BACKGROUND: Since 1985, the Committee on Professional Liability of the American Society of Anesthesiologists has evaluated closed anesthesia malpractice claims. This study compared pediatric and adult closed claims with respect to the mechanisms of injury, outcome, the costs, and the role of care judged to be substandard. METHODS: Using a standardized form and method developed for analysis of closed claims, the American Society of Anesthesiologists Closed Claims Data Base was used to compare pediatric with adult anesthesia-related adverse events. RESULTS: Of the 2,400 total claims, 238 (10%) were in the pediatric age group (15 yr of age or younger). The pediatric claims presented a different distribution of damaging events compared with that of adults. In particular, respiratory events were more common among pediatric claims (43% versus 30% in adult claims; P < or = 0.01). The mortality rate was greater in the pediatric claims (50% versus 35% in adult claims; P < or = 0.01), anesthetic care more often was judged less than appropriate (54% versus 44% in adult claims; P < or = 0.01), the complications more frequently were thought to be preventable with better monitoring (45% versus 30% in adult claims; P < or = 0.01), and the distribution of payments to the plaintiff was different (median payment, $111,234 versus $90,000 in adult claims; P < or = 0.05). Many of the differences between pediatric and adult claims were explained by a higher prevalence of patient injury caused by inadequate ventilation in the pediatric claims (20% versus 9% in adult claims; P < or = 0.01). In pediatric compared with adult inadequate ventilation claims, poor medical condition and/or obesity (6% versus 41%; P < or = 0.01) were uncommon associated factors. Cyanosis (49%) and/or bradycardia (64%) often preceded cardiac arrest in pediatric claims related to inadequate ventilation, resulting in death (70%) or brain damage (30%) in previously healthy children. Although clinical clues suggested hypoxemia as a common mechanism of injury, the files did not contain enough information to explain the genesis of hypoxemia in these claims. CONCLUSIONS: Comparison of adult and pediatric closed claims revealed a large prevalence of respiratory related damaging events--most frequently related to inadequate ventilation. In the opinion of the reviewers, 89% of the pediatric claims related to inadequate ventilation could have been prevented with pulse oximetry and/or end tidal CO2 measurement. However, pulse oximetry appeared to prevent poor outcome in only one of seven claims in which pulse oximetry was used and could possibly have done so.

Amrinone reduces pulmonary vascular resistance elevated by U46619 in isolated perfused lungs.

The effects of amrinone on pulmonary vascular resistance (PVR) were studied in an isolated, perfused rabbit lung model where all the major determinants of PVR were controlled. In this preparation, the alveolar oxygen and carbon dioxide tensions, vascular pH and vascular oxygen and carbon dioxide tensions, and zonal conditions of the lung and phasic variations of pulmonary artery pressures could be precisely measured and controlled. Measurements of PVR were made by a complete determination of the pulmonary pressure-flow curve and determination of the PVR under identical flow conditions for all studies. This approach allowed a more precise determination of the primary effects of amrinone on normal and elevated PVR than has been previously possible. We found that amrinone in final concentrations of either 4 or 8 micrograms/ml had no effect on basal PVR and no effect on lung water weight to dry ratios. When PVR was elevated by the addition of the thromboxane A2 mimetic U46619, amrinone reduced the PVR by 27% at a final concentration of 4 micrograms/ml and by 74% at a final concentration of 8 micrograms/ml. We conclude that in the doses tested, amrinone has no effects on basal PVR but is able to reduce elevated PVR in a dose-dependent manner. These results are the first to demonstrate clearly that amrinone has the ability to reduce elevated pulmonary vascular tone through a direct mechanism and not through secondary effects on other determinants of PVR such as left atrial pressure (Pla), increased cardiac output with resultant vascular recruitment, or increases in mixed venous oxygen tension. The possible implications for the clinical use of amrinone in situations of elevated PVR are discussed.

Oxygen delivery and consumption during hypothermia and rewarming in the dog.

Changes in oxygen consumption (VO2) and oxygen delivery (DO2) were compared in three groups of paralyzed, sedated dogs: 1) a group (n = 5) cooled to 29 degrees C and immediately rewarmed to 37 degrees C; 2) a group (n = 5) cooled to and maintained at 29 degrees C for 24 h, and then rewarmed; and 3) a group (n = 5) maintained at 37 degrees C for 24 h. During the cooling phase, in both the acute and prolonged hypothermia animals, VO2 and DO2 decreased significantly from control values (P less than 0.05). The decrease in DO2 occurred as a result of a similar decrease in cardiac index (CI; P less than 0.05) that was associated with a significant increase in systemic vascular resistance index (SVRI; P less than 0.05). Arteriovenous oxygen content difference (C(a-v)O2), O2 extraction ratio, mixed venous oxygen tension (PVO2), pH, and base deficit (BD) were not different from control values even during prolonged hypothermia. Normothermic control dogs also demonstrated a significant decrease in CI (P less than 0.05) at 24 h. Surface rewarming increased VO2 back to control values in the acute hypothermia group and to values above control (P less than 0.05) in the prolonged hypothermia group. DO2 remained below control in both groups, resulting in a significant increase in O2 extraction (P less than 0.05) and a decrease in PVO2 (P less than 0.05) in the prolonged hypothermia animals. Following rewarming administration of sodium nitroprusside returned DO2, CI, and SVRI to control values but did not increase VO2. All animals survived the study without need for inotropic support.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of pH and PCO2 on pulmonary and systemic hemodynamics after surgery in children with congenital heart disease and pulmonary hypertension.

Fourteen children with congenital heart disease and associated pulmonary hypertension (preoperative mean pulmonary artery pressure (MPAP) 48 mm Hg +/- 1 SEM were examined to determine the effect of arterial carbon dioxide tension (PaCO2) and pH on pulmonary and systemic hemodynamics after surgical repair. Baseline measurements were obtained with hyperventilation to PaCO2 20 to 30 mm Hg (pH 7.56 +/- 0.01 mm Hg). The addition of carbon dioxide to inspired gas to achieve a PaCO2 40 to 45 mm Hg (pH 7.35 +/- 0.01) resulted in a significant increase in MPAP, from 32 +/- 5 mm Hg to 47 +/- 8 mm Hg (p less than 0.05). An increase in mean cardiac index (CI) from 2.7 +/- 0.3 L/min/m2 to 3.3 +/- 0.3 L/min/m2 (p less than 0.05) explained in part the associated increase in MPAP. For a subgroup of eight patients with postoperative MPAP greater than 30 mm Hg (at pH 7.35 to 7.40), pulmonary vascular resistance index (PVRI) also significantly increased (p less than 0.05) as PaCO2 was increased, implying a direct pulmonary vasodilating effect of alkalosis. Removal of carbon dioxide from inspired gas returned hemodynamic values to baseline. The higher the MPAP at physiologic pH the greater the absolute amount of MPAP reduction and PVRI reduction (p less than 0.05) with alkalosis. No complications from alkalosis were seen. We suggest that a trial of hypocarbic alkalosis in the child with severe residual pulmonary hypertension after surgical repair of congenital heart disease is warranted to reduce right ventricular afterload.

Short-acting barbiturate sedation: effect on arterial pH and PaCO2 in children.

One hundred and fifteen unpremedicated children, induced with thiamylal, a short-acting thiobarbiturate, administered rectally (25 mg.kg-1 body wt) or intravenously (6 mg.kg-1) had arterial pH of 7.36 +/- 0.03 and PaCO2 of 40 +/- 4 mmHg. In 22 children over two years of age, the use of fentanyl (1.2 +/- 0.7 microgram.kg-1) in addition to the thiamylal did not change blood gas data compared to those children over two years receiving only barbiturates (pH 7.36 vs 7.36, PaCO2 41 vs 40 mmHg). Children with cyanotic congenital heart disease showed similar pH and PaCO2 to acyanotic children following administration of the short-acting barbiturate. Thiobarbiturates, given in a titrated fashion under direct observation, have clinically small effects on arterial pH and PaCO2 in paediatric patients.