Kirk Lalwani

Pediatric sedation in North American children's hospitals: a survey of anesthesia providers.

Background : Information about the existence and organization of pediatric sedation services in North America is not available. We conducted a survey to collect this information from anesthesiologists at pediatric institutions and to identify factors perceived as limiting the development of sedation services.

The laryngeal mask airway for pediatric adenotonsillectomy: Predictors of failure and complications

OBJECTIVES We hypothesize that the laryngeal mask airway (LMA) is a safe technique for airway management in pediatric adenotonsillectomy (T&A). METHODS After institutional review board (I.R.B.) approval, we conducted a retrospective review of 1199 medical records of children who underwent T&A from 2002 to 2006 at Doernbecher Childrens Hospital, a teaching institution in Portland, OR. There were no significant demographic differences between the LMA (n=451), endotracheal tube (ETT) (n=715), and failed LMA groups (n=33). Outcome variables were LMA failure (LMA replaced with endotracheal tube), and any complication. We collected demographic and medical data to determine the incidence and predictors of LMA failure, and to characterize the failed LMA group. RESULTS The incidence of LMA failure was 6.8%. Patients who underwent adenoidectomy had significantly lower odds of LMA failure compared to patients who had a tonsillectomy or adenotonsillectomy (OR 0.28, 95% CI 0.15-0.52, P<0.0001). One of the surgeons (OR 0.46, 95% CI 0.45-0.48, P<0.0001) was also associated with decreased odds of LMA failure. Controlled ventilation (OR 7.17, 95% CI 4.99-10.32, P<0.0001), and younger patients (OR 1.05 for each year decrease in age, 95% CI 1.03-1.07, P ≤ 0.0001) were associated with increased odds of LMA failure. The complication rate was 14.2% in the LMA group and 7.7% in the ETT group. Increased odds of developing any complication were seen in male patients (OR 1.4, 95% CI 1.01-1.7, P=0.04), and in patients with co-morbidities other than obstructive sleep apnea syndrome or upper respiratory tract infection (OR 4.2, 95% CI 1.03-17.2, P=0.04). The odds of developing a complication were lower in the ETT group compared to the LMA group (0.63, 0.46, 0.8, P=0.005). CONCLUSIONS LMA use for pediatric T&A is associated with a higher incidence of complications, mainly as a result of airway obstruction following insertion of the LMA or McIvor gag placement. Complications were more likely if tonsillectomy was performed when compared to adenoidectomy alone. Appropriate patient selection, careful insertion, and avoidance of controlled ventilation may decrease the incidence of LMA failure, especially if tonsillectomy is performed. The ability of surgeons to work around the LMA can modify the failure rate significantly.

Cardiac arrest in the neonate during laparoscopic surgery

We describe a case of intraoperative neonatal cardiac arrest during attempted laparoscopic surgery. Circulatory collapse occurred before peritoneal insufflation, initially obscuring the diagnosis. Emergent transthoracic echocardiography during resuscitation demonstrated intracardiac gas bubbles consistent with venous gas embolism. The site of entrainment was probably a bleeding umbilical vein transected by the umbilical trocar. Greater awareness of this complication in neonates will facilitate early diagnosis and encourage preventive measures, such as the avoidance of umbilical vessels, use of an open instead of closed access technique, and ligation of bleeding vessels after peritoneal access.

The 'dark' side of sedation: 12 years of office-based pediatric deep sedation for electroretinography in the dark.

Objectives:  Analyze pediatric ERG data for adverse events, interventions, and outcomes of propofol sedations performed in near‐complete darkness.

The effect of nitrous oxide on intra-ocular pressure in healthy adults*

Many anaesthetic agents affect intra‐ocular pressure, yet little is known about nitrous oxide and intra‐ocular pressure. This study assessed the effect of nitrous oxide on intra‐ocular pressure in 20 healthy adult volunteers. The intra‐ocular pressure was measured at baseline, while breathing a 70:30 mix of nitrous oxide and oxygen for 12 min, and then while breathing room air for 15 min. A linear mixed effects model was used to assess change in intra‐ocular pressure over time. There was no significant difference in intra‐ocular pressure between baseline and during or after nitrous oxide inhalation. Several differences in intra‐ocular pressure were noted between internal time‐points: pressure increased by 2.4 mmHg between 3 and 6 min of breathing nitrous oxide (p = 0.01); it increased by 1.4 mmHg between 3 and 9 min of breathing nitrous oxide (p = 0.046); and it decreased by 2.2 mmHg between 6 min of breathing nitrous oxide and 15 min of breathing room air (p = 0.035). This study indicates that nitrous oxide inhalation does not significantly change intra‐ocular pressure from baseline values in a population of healthy adults.

Aerophagia and anesthesia: An unusual cause of ventilatory insufficiency in a neonate

We describe a healthy neonate with abdominal distention, inadequate ventilation, and delayed extubation during anesthesia for minor surgery. Following rectal decompression and successful extubation, extreme abdominal distention recurred postoperatively after ingestion of clear fluids. We elicited a history of frequent and excessive flatus from the parents, and abdominal radiography revealed distended loops of small bowel with small lung volumes suggestive of aerophagia. The differential diagnosis of aerophagia is reviewed, the anesthetic implications discussed, and relevant literature pertaining to this condition summarized.

Complications of three deep sedation methods for magnetic resonance imaging

Background: Propofol and pentobarbital are commonly used to sedate children undergoing magnetic resonance imaging (MRI). Aim/Objective: To compare the safety of three types of sedation: intravenous propofol (PROP), mixed pentobarbital/propofol (PENT), and mixed pentobarbital group requiring supplemental sedation (PENT SUPP) regimens in pediatric patients following deep sedation (DS) for noncardiac MRI. Materials and Methods: We conducted a case-control study matching 619 cases with complications with 619 controls using data from our institutions sedation database for children deeply sedated for noncardiac MRI. Cases were defined as patients with any complication and we characterized complications from cases, and used a conditional logistic regression model to assess the association between three DS methods and occurrence of complications after adjusting for confounding variables. Results: We found that complications occurred in association with 794 (10.1%) of the 7,839 DSs performed for MRI between 1998 and 2008. Of the 794 cases, 619 cases met inclusion criteria for the study. Among the 619 cases that met inclusion criteria, 24 (0.3% of 7,839 DSs total) were associated with major complications. Type of sedation was significantly associated with the occurrence of complications, and the PENT group was associated with decreased odds of complications when compared to the PROP regimen (OR 0.68; 95% CI 0.46, 0.98; P=0.040) and compared to the PENT SUPP group (OR 0.60; 95% CI 0.31, 0.89; P<0.0001). Conclusions: DS with a pentobarbital technique was associated with decreased odds for complications when compared to a propofol-based technique or a pentobarbital technique requiring supplemental sedation.

Delicious but Malicious

This case discusses the synergistic pharmacodynamic interaction between the mineralocorticoid activity of licorice, and the diuretic effects of hydrochlorothiazide, each contributing to the development of hypokalemia.

A HAART-breaking Tale

This case discusses the synergistic pharmacodynamic interaction between metformin and tenofovir, resulting in lactic acidosis and renal failure.

The Scary Side of Ginkgo biloba Is No Match for an Anesthesia Superstar: Seizures

This case discusses the pharmacokinetic interaction between phenytoin and Ginkgo biloba, resulting in breakthrough seizures. Phenytoin is a cytochrome P450 2C19 substrate and Ginkgo biloba is a 2C19 inducer.