Volume guarantee ventilation during surgical closure of patent ductus arteriosus.

BACKGROUND: Surgical closure of patent ductus arteriosus (PDA) is associated with adverse outcomes. Surgical exposure requires retraction of the lung, resulting in decreased aeration and compliance. Optimal respiratory support for PDA surgery is unknown. Experience with volume guarantee (VG) ventilation at our institution led us to hypothesize that surgery would be better tolerated with automatic adjustment of pressure by VG to maintain tidal volume (VT) during retraction. OBJECTIVE: The objective of this study was to describe ventilator support, VT, and oxygenation of infants supported with VG during PDA surgery. DESIGN/METHODS: Ventilator variables, oxygen saturation, and heart rate were recorded during PDA surgery in a convenience sample of infants during PDA closure on VG. Pressure limit increased 11% and set VT was 26% lower during lung retraction. Fentanyl and pancuronium/vecuronium were used for anesthesia/muscle relaxation. Longitudinal data were analyzed by analysis of variance for repeated measures. RESULTS: Seven infants, 25.4 ± 1.5 weeks and 723 ± 141 g, underwent closure of PDA on VG at a mean age 29.9 days. No air leak, bradycardia, or death occurred. Target VT was maintained with a modest increase in inflation pressure. Oxygenation remained adequate. CONCLUSIONS: VG avoided hypoxemia and maintained adequate VT with only a modest increase in peak inflation pressure and thus may be a useful mode during PDA surgery.

Techniques of intrauterine fetal transfusion for women with red-cell isoimmunisation for improving health outcomes.

BACKGROUND: Red-cell alloimmunisation can occur when there are incompatibilities between a woman's blood type and that of her unborn baby. This can cause the baby to become anaemic (low red blood cell count), which may require treatment during the pregnancy by blood transfusion while the baby remains within the uterus (called an intrauterine blood transfusion). OBJECTIVES: To compare, using the best available evidence, the benefits and harms of different techniques of intrauterine fetal blood transfusion for women with red-cell alloimmunisation. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (13 June 2012). SELECTION CRITERIA: We considered randomised controlled trials comparing different techniques of intrauterine fetal blood transfusion (either alone or in combination with another technique) for inclusion. DATA COLLECTION AND ANALYSIS: Two authors evaluated trials under consideration for appropriateness for inclusion and methodological quality, without consideration of their results according to the prestated eligibility criteria. We planned to use a fixed-effect meta-analysis for combining study data if we judged the trials to be sufficiently similar. We planned to investigate statistical heterogeneity using the I² statistic; if this indicated a high degree of statistical heterogeneity, we planned to use a random-effects model. MAIN RESULTS: Our search strategy identified four reports of three studies for consideration, of which two met the inclusion criteria, involving 44 women. We identified a single trial comparing the use of intrauterine fetal blood transfusion and intravenous immunoglobulin versus intrauterine fetal blood transfusion alone, and a single trial comparing the use of atracurium and pancuronium. There were no statistically significant differences identified for any of the reported outcomes. AUTHORS' CONCLUSIONS: There is little available high quality information from randomised controlled trials to inform the optimal procedural technique when performing fetal intrauterine fetal blood transfusions for women with an anaemic fetus due to red cell alloimmunisation. Further research evaluating the benefits and harms associated with different techniques is required.

[Influence of the agents which maintain the coordination between spontaneous breathing and mechanical ventilation on haemodynamics and respiration].

OBJECTIVE: To investigate the haemodynamic and respiratory changes following intravenous administration with midazolam, pavulon or both of them in the patients having incoordination between spontaneous breathing and mechanical ventilation. METHODS: Thirty patients having incoordination between spontaneous breathing and mechanical ventilation were randomly assigned to receiving intravenous injection of pavulon (group 1), midazolam (group 3), and both (group 2) respectively with 10 cases in each group. The degree of coordination between spontaneous breathing and mechanical ventilation, blood pressure (BP), heart rate (HR), respiration frequency (RF), oxygen saturation of pulse (SpO(2)) were observed before the medication and at 5, 15, 30 and 60 minutes following the administration of drugs in all the patients. RESULTS: Incoordination between spontaneous breathing and mechanical ventilation, fast RF, decreased SpO(2) were observed before the drug in all patients. Improvement of respiratory was significant in group 2. Patients in group 2 were in excellent coordination between spontaneous breathing and mechanical ventilation, reaching 100% within 30 minutes after administration, and lasting longer. The haemodynamics maintained stable and a significant improvement in respiration and SpO(2) were found. BP and HR were elevated significantly, and RF and hypoxemia were improved, and the degree of coordination between spontaneous breathing and mechanical ventilation reached 100% 5 minutes after the drug, but with shorter duration in group 1. There were no obvious changes in BP, HR, RF and hypoxemia, and the degree of coordination between spontaneous breathing and mechanical ventilation was lowest in group 3. CONCLUSION: The combined use of midazolam and pavulon has little influence on circulation, and it also can maintain the coordination between spontaneous breathing and mechanical ventilation. It is suggested that the combined use of midazolam and pavulon is an optimal way to improve the ventilatory function in mechanical ventilation.

Risk factors for sensorineural hearing loss in survivors with severe congenital diaphragmatic hernia.

Recent improvements in perinatal management have improved the prognosis in patients with severe congenital diaphragmatic hernia (CDH). However, in surviving patients with severe CDH, hearing loss has sometimes been reported to occur during the follow-up period. Although some of the risk factors for developing sensorineural hearing loss (SNHL) have been reported in CDH, no definitive risk factors have yet been reported. We, therefore, investigated the risk factors regarding postnatal management in patients with severe CDH. In 16 surviving patients with severe CDH, which had all been detected antenatally, and whose lung-to-thoracic ratio was less than 0.2, four patients demonstrated late onset SNHL, which occurred between 1.5 and 5 years of age. The risk factors for SNHL regarding the postnatal treatment for CDH were analyzed between the four patients with SNHL and the remaining 12 patients without SNHL, regarding such factors as the use of ototoxic drugs, neuromuscular blocking agents, high-frequency oscillation (HFO), and inhaled nitric oxide, the duration of hypocapnia, hypoxia, severe acidosis, severe alkalosis, and mechanical ventilation. In addition, the types of neuromuscular blocking agents were also analyzed, including the administration of pancuronium bromide (PB) and vecuronium bromide (VB). The patients with SNHL were found to have a significantly higher risk than the patients without SNHL regarding the duration of loop diuretics usage and the duration of usage of both mechanical ventilation and HFO. Furthermore, all four patients with SNHL used PB. In contrast, none of the five patients using VB developed SNHL The duration and cumulative dose of PB used in the patients with severe CDH showed a significant correlation to the occurrence of SNHL. Although this study was retrospective, based on our data, the prolonged use of PB, in addition to the duration of treatment by loop diuretics, mechanical ventilation, and HFO usage, might, thus, be suggested to be a possible risk factor for late onset SNHL in patients with severe CDH.

Neuroparalysis and ventilatory support in severe tetanus.

In severe form of tetanus, even with maximum dose of muscle relaxants, spasms and apnoeic spells may persist and that may be life-threatening. The aim of this study was to assess the effect of neuroparalysing the patients and then providing ventilatory support in bringing about their recovery. Forty-nine adult patients of severe tetanus (Ablett's grade IIIA--6 patients and Ablett's grade IIIB--43 patients) were studied during the period from April, 1993 to February, 1996. Mean period of onset ie, period from trismus to first spasm, in these patients was 24 hours. Patients were neuroparalysed with a bolus dose of 2-4 mg of pancuronium followed by a continuous infusion of 1-2 mg/hour and simultaneously supported with mechanical ventilation until spasms subsided. Fourteen patients (28.6%) survived and rest died. Mean duration of ventilatory support on survived patients was 14.4 days. The commonest complication encountered during ventilatory support was respiratory tract infection observed in 36 patients (73.5%). Commonest cause of death was autonomic imbalance encountered in 15 patients (30.6%). Treatment of choice in severe tetanus should be neuroparalytic ventilatory support. With use of new generation ventilators and better intensive care facility, death in severe tetanus is likely to be very less.

Off-pump coronary artery bypass grafting: a case report.

It is easy to take for granted the seemingly effortless way cardiovascular surgeons are able to bypass atherosclerotic coronary arteries. The process used today was developed over many years of rigorous study, experimentation, success, and failure. Early cardiac surgery was performed blindly, through small incisions, on a beating heart. Advances in medicine allowed surgery to be performed on hearts stilled by cardioplegic arrest, while the circulation was continued through the use of a cardiopulmonary bypass (CPB) machine. The development of the CPB machine allowed surgeons to perform the delicate work of coronary artery bypass grafting (CABG), first attempted on dogs, and then humans. This article briefly outlines the historical evolution of cardiac surgery that led to the development of the technology necessary to perform off-pump coronary artery bypass grafting (OPCAB). A case report of a 72-year-old female who underwent OPCAB is outlined. Included is a discussion of some of the benefits and potential complications of CABG and OPCAB. Anesthetic considerations for OPCAB procedures also are presented.

Ototoxic drugs and sensorineural hearing loss following severe neonatal respiratory failure.

AIM: To determine relationships between ototoxic drugs and 4-y sensorineural hearing loss (SNHL) in near-term and term survivors of severe neonatal respiratory failure. METHODS: All 81 survivors of the Canadian arm of the Neonatal Inhaled Nitric Oxide Study (mortality 32, loss to follow-up 9) received loop diuretics, aminoglycosides, and neuromuscular blockers (NMB), and 50 received vancomycin as neonates. Prospective, longitudinal secondary outcome using audiological tests diagnosed late-onset, progressive SNHL in 43 (53%); not flat (sloping) in 29, flat (severe to profound) in 14. Risk for SNHL was determined. RESULTS: A combination of duration of diuretic use of >14 d and average NMB dose of >0.96 mg/kg/d contributed to SNHL among survivors (odds ratio 5.2; 95% CI 1.6, 16.7). Markers of illness severity did not contribute. Dosage or duration of aminoglycosides use did not relate to SNHL. Cumulative dosages and duration of use of diuretics; NMB; use of vancomycin; and overlap of diuretics with NMB, aminoglycosides, and vancomycin individually linked to SNHL (p<0.001). CONCLUSION: Overuse of loop diuretics and/or NMB contributes to SNHL after neonatal respiratory failure; markers of illness severity or the appropriate administration of aminoglycosides do not.

[Italian guidelines and recommendations for prevention and treatment of pain in the newborn]. / Linee-guida e raccomandazioni per la prevenzione ed il trattamento del dolore nel neonato.

OBJECTIVE: Despite accumulating evidence that procedural pain experienced by preterm infants may have acute detrimental and even long-term effects on an infant's subsequent behavior and neurological outcome, neonates admitted to Neonatal Intensive Care Units still frequently experience acute and prolonged uncontrolled pain. Many invasive and surgical procedures are routinely performed at the bedside in the NICU without adequate pain management. AIM: To develop evidence-based guidelines and recommendations for pain control and prevention in Italian i.e. heel lancing, venipuncture and percutaneous venous line positioning, tracheal intubation, mechanical ventilation, lumbar puncture, chest tube positioning, for certain surgical procedures performed at the NICU, e.g. central venous cutdown, surgical PDA ligation, and cryotherapy, laser therapy for ROP, and for postoperative pain management. CONCLUSION: Adequate pain prevention and management should be an essential part of standard health care at the NICU, and recognizing and assessing sources of pain should be routine in the day-to-day practice of physicians and nurses taking care of the newborn. We hope these guidelines will contribute towards increasing the NICU caregiver's awareness and understanding of the importance of adequate pain control and prevention.

Neuromuscular paralysis for newborn infants receiving mechanical ventilation.

BACKGROUND: Ventilated newborn infants breathing in asynchrony with the ventilator are at risk for complications during mechanical ventilation, such as pneumothorax or intraventricular hemorrhage, and are exposed to more severe barotrauma, which consequently could impair their clinical outcome. Neuromuscular paralysis, which eliminates spontaneous breathing efforts of the infant, has potential advantages in this respect. However, a number of complications have been reported with muscle relaxation in infants, so that concerns exist regarding the safety of prolonged neuromuscular paralysis in newborn infants. OBJECTIVES: To determine whether routine neuromuscular paralysis of newborn infants receiving mechanical ventilation compared with no routine paralysis results in clinically important benefits or harms. SEARCH STRATEGY: The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2004), MEDLINE (from 1966 to April 2004) and EMBASE (from 1988 to April 2004) were searched. References of review articles were hand searched. Language restriction was not imposed. SELECTION CRITERIA: All trials using random or quasi-random patient allocation, in which the routine use of neuromuscular blocking agents during mechanical ventilation was compared to no paralysis or selective paralysis in newborn infants. Methodological quality was assessed blindly and independently by the two authors. DATA COLLECTION AND ANALYSIS: Data were abstracted using standard methods of the Cochrane Collaboration and its Neonatal Review Group, with independent evaluation of trial quality, and abstraction and synthesis of data by both authors. Treatment effect was analysed using relative risk, risk difference and weighted mean difference. MAIN RESULTS: Ten possibly eligible trials were identified, of which six were included in the review. All the included trials studied preterm infants ventilated for respiratory distress syndrome, and used pancuronium as the neuromuscular blocking agent. In the analysis of the results of all trials, no significant difference was found in mortality, air leak or chronic lung disease, but there was a significant reduction in intraventricular hemorrhage and a trend towards less severe intraventricular hemorrhages. In the subgroup analysis of trials studying a selected population of ventilated infants with evidence of asynchronous respiratory efforts, a significant reduction in intraventricular hemorrhage (any grade and severe IVH) was found, and a trend towards less air leak. In the subgroup analysis of trials studying an unselected population of ventilated infants, no significant differences were found for any of the outcomes. AUTHORS' CONCLUSIONS: For ventilated preterm infants with evidence of asynchronous respiratory efforts, neuromuscular paralysis with pancuronium seems to have a favourable effect on intraventricular hemorrhage and possibly on air leak. Uncertainty remains, however, regarding the long term pulmonary and neurologic effects, and regarding the safety of prolonged use of pancuronium in ventilated newborn infants. There is no evidence from randomized trials on the effects of neuromuscular blocking agents other than pancuronium. The routine use of pancuronium or any other neuromuscular blocking agent in ventilated newborn infants cannot be recommended based on current evidence.

Interaction between mivacurium and pancuronium: impact of the order of administration.

INTRODUCTION: Potentiation of mivacurium by low-dose pancuronium is mostly due to an inhibition of plasma butyryl cholinesterase (BchE) resulting in a decreased rate of hydrolysis of mivacurium. Nevertheless, an interaction at the receptor site could not be ruled out. By changing the order of the muscle relaxant injections, we may lessen the pharmacokinetic interaction and assess the impact at the acetylcholine receptor level. METHODS: Twenty patients scheduled for general anesthesia with propofol and fentanyl, and isoflurane were randomized into two groups receiving, mivacurium 100 microg kg-1 followed by pancuronium 15 microg kg-1 (group 1) or pancuronium 15 microg kg-1 followed by mivacurium 100 microg kg-1 (group 2). BchE before and after injection of each relaxant was measured. Neuromuscular block was assessed with a force transducer at the adductor pollicis measuring the elicited twitch to ulnar nerve stimulation. RESULTS: The neuromuscular block was greater when pancuronium was administered before mivacurium (100% versus 96+/-3%; P<0.05). Times to recovery of the elicited twitch response to 25% and 75% of control value were increased by 100% (P<0.05). After pancuronium, decreases in BchE of 11% and 14% in groups 1 and 2 were observed, respectively. CONCLUSION: Interaction between mivacurium and low dose pancuronium is significant only when mivacurium is injected after pancuronium.

Midlatency auditory-evoked potentials in the assessment of sedation in cardiac surgery patients.

OBJECTIVES: Midlatency auditory-evoked potentials (MLAEPs) may provide an objective measure of depth of sedation. The aim of this study was to evaluate MLAEPs for measuring sedation in cardiac surgery patients. DESIGN: Prospective study. SETTING: Intensive care unit of a university hospital. PARTICIPANTS: Twenty-two patients scheduled for elective coronary artery bypass grafting. INTERVENTIONS: MLAEPs were obtained at 5 time points: the day before surgery (baseline), 1 hour before surgery, after premedication, postoperatively during deep (Ramsay 6) and moderate (Ramsay 4) sedation, and the day after surgery. MEASUREMENTS AND MAIN RESULTS: The latency of the Nb MLAEP component increased from 44 ms (38-60 ms; median, range) at baseline to 49 ms (41-64 ms) after premedication (p = 0.03) and further to 63 ms (48-80 ms) during deep sedation after surgery (P < 0.01). Although a decreasing clinical level of sedation after rewarming was not associated with a significant change in Nb latency (61 ms [42-78 ms]), the MLAEP NaPa amplitude increased from 0.9 muV (0.4-1.6 microV) to 1.3 muV (0.8-3.9 microV; p = 0.01). Nb latency remained increased the day after surgery (49 ms [37-71 ms]) as compared with baseline (p < 0.01). CONCLUSIONS: MLAEP latencies can reflect subtle changes in auditory perception, while amplitudes seem to change with transition between deep levels of sedation.

[Strychnine poisoning]. / Strychninvergiftung.

HISTORY AND ADMISSION FINDINGS: A 46-year-old man presented two hours after ingestion of about 250 mg strychnine with severe violent, generalized convulsions, triggered by external stimuli. During the convulsion-free periods there were no abnormal signs in the physical examination. INVESTIGATION: The presence of strychnine was confirmed by urine analysis with gas chromatography-mass spectrometry. TREATMENT AND COURSE: Because diazepam as anticonvulsant of choice was not effective in abating the convulsions the patient was intubated. A combination with midazolam, fentanyl and pancuronium was effective in controlling the convulsions. The patient was discharged from ICU on day three. CONCLUSION: Fatal outcome of strychnine poisoning demands an aggressive management with early intubation, control of muscle tremors and prevention of rhabdomyolisis and renal failure.

Quantitative assessment of tracheal collapsibility in infants with tracheomalacia.

Infantile tracheomalacia is a potentially life-threatening disease requiring prolonged artificial respiratory support. Diagnosis and management of this disease may be further improved by establishing a suitable objective and quantitative assessment protocol for tracheal collapsibility. It is our hypothesis that tracheal collapsibility can be represented by the relationship between intraluminal pressure and the cross-sectional area of the trachea. To test this hypothesis, static pressure/area relationships of the trachea were obtained from anesthetized and paralyzed infants, who were diagnosed as having tracheomalacia by endoscopic observation. These relationships were fitted on a linear regression model, followed by calculation of the estimated closing pressure. The tracheal closing pressure ranged from -8 to -27 cm H(2)O, suggesting easy collapsibility of the trachea during crying or coughing and noncollapsibility during the spontaneous respiratory cycle, which coincided with the infants' symptoms. It is our conclusion that tracheal collapsibility of infants with tracheomalacia can be quantitatively assessed by the static pressure/area relationship of the trachea obtained under general anesthesia and paralysis.

Anesthetic considerations during caval inflow occlusion in children with congenital heart disease.

OBJECTIVE: Caval inflow occlusion (IO) was introduced to facilitate surgical pulmonary and aortic valvotomy without cardiopulmonary bypass (CPB). Although a technique that is used infrequently today, it remains useful in some patients with complex single-ventricle congenital cardiac defects who require an atrial septectomy. The potential for complications and anesthetic considerations have not been described previously. DESIGN: Retrospective review. SETTING: A tertiary care university teaching children's hospital. PARTICIPANTS: Eleven children, median age 3 months (range 3 days-3 years) who underwent (IO) technique for atrial septectomy. INTERVENTIONS: Atrial septectomy under IO in patients with restrictive atrial septum. MEASUREMENTS AND MAIN RESULTS: Eleven children, median age 3 months (range 3 days-3 years), underwent IO for atrial septectomy. Mean duration of IO was 87.7 +/- 25.5 seconds. There was 1 intraoperative death (9%). After release of the caval clamps, inotropic support was necessary in 7 of 11 patients, arrhythmias occurred in 4 of 11 patients (2 atrial and 2 ventricular fibrillation), and 10 of 11 patients required blood transfusion along with boluses of calcium gluconate and sodium bicarbonate to support the circulation immediately post-IO. Duration of postoperative mechanical ventilation was 2.2 +/- 1.6 days; 10 of 11 patients (91%) survived to discharge with mean length of intensive care unit stay 3.7 +/- 2.2 days. CONCLUSION: IO is an effective technique for short intracardiac procedures without the need for CPB. Close collaboration between anesthesia and surgical staff is essential to keep the duration of IO as short as possible and because of the potential for hemodynamic instability.

Anaesthetic experiences in three sets of conjoined twins in King Chulalongkorn Memorial Hospital.

We describe the anaesthetic management for magnetic resonance image scanning, angiography and surgical operations in three sets of conjoined twins (ischiopagus, throracopagus and pygopagus) in King Chulalongkorn Memorial Hospital during 1996-2002. The anaesthetic technique and associated problems are summarized.