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J Roger Maltby

Publications and source records attributed to J Roger Maltby.

6 recordsLinked to original sources
PubMed2006

Fasting from midnight--the history behind the dogma.

The purpose of this chapter is to review historical fasting guidelines and how the dogma of fasting from midnight arose and came to be challenged by randomized clinical trials of preoperative clear liquids versus overnight fast. Medical and anaesthesia textbooks and journals from the 19th and 20th centuries were consulted, and the results of clinical trials and the reaction to them are reviewed. The dogma appeared to result from extrapolation of pulmonary aspiration risk in 'full-stomach' emergency cases to healthy elective cases. This was reinforced when 25 mL in the stomach, present in half of all healthy fasting patients, was used as a surrogate marker for high risk of aspiration. Subsequent large-scale studies showed the risk to be minimal. Meta-analysis of randomized clinical trials demonstrated the safety of clear oral liquids until 2 hr preoperatively in healthy patients undergoing elective surgery. Reaction was cautious but led to eventual acceptance of evidence-based fasting guidelines.

Anesthesia↗
PubMed2004

Drinking 300 mL of clear fluid two hours before surgery has no effect on gastric fluid volume and pH in fasting and non-fasting obese patients.

PURPOSE: To determine whether, in obese [body mass index (BMI) > 30 kg.m(2)] patients, oral intake of 300 mL clear liquid two hours before elective surgery affects the volume and pH of gastric contents at induction of anesthesia. METHODS: A single-blind, randomized study of 126 adult patients, age > or = 18 yr, ASA physical status I or II, BMI > 30 kg.m(2) who were scheduled for elective surgery under general anesthesia. Patients were excluded if they had diabetes mellitus, symptoms of gastroesophageal reflux, or had taken medication within 24 hr that affects gastric secretion, gastric fluid pH or gastric emptying. All patients fasted from midnight and were randomly assigned to fasting or fluid group. Two hours before their scheduled time of surgery, all patients drank 10 mL of water containing phenol red 50 mg. Those in the fluid group followed with 300 mL clear liquid of their choice. Immediately following induction of general anesthesia and tracheal intubation, gastric contents were aspirated through a multiorifice Salem sump tube. The fluid volume, pH and phenol red concentration were recorded. RESULTS: Median (range) values in fasting vs fluid groups were: gastric fluid volume 26 (3-107) mL vs 30 (3-187) mL, pH 1.78 (1.31-7.08) vs 1.77 (1.27-7.34) and phenol red retrieval 0.1 (0-30)% vs 0.2 (0-15)%. Differences between groups were not statistically significant. CONCLUSION: Obese patients without comorbid conditions should follow the same fasting guidelines as non-obese patients and be allowed to drink clear liquid until two hours before elective surgery, inasmuch as obesity per se is not considered a risk factor for pulmonary aspiration.

Adult↗
PubMed2003

LMA-Classic and LMA-ProSeal are effective alternatives to endotracheal intubation for gynecologic laparoscopy.

PURPOSE: To compare the laryngeal mask airways (LMA), LMA-Classic(TM) (LMA-C) and LMA-ProSeal(TM) (PLMA) with the endotracheal tube (ETT) with respect to pulmonary ventilation and gastric distension during gynecologic laparoscopy. METHODS: We stratified 209 women, aged > or = 18 yr, ASA physical status I-III, by body mass index as non-obese (< or = 30 kg x m(-2)) or obese (> 30 kg x m(-2)) and randomized them to LMA-C/PLMA or ETT groups for airway management. Anesthesia was induced with propofol, fentanyl and succinylcholine or rocuronium. In the LMA-C/PLMA group we used a size 4 LMA-C in non-obese patients and size 4 or 5 PLMA in obese patients. In the ETT group we used a cuffed 7.0 mm ETT in all patients. Anesthesia was maintained with isoflurane in nitrous oxide and 30-50% oxygen, fentanyl and neuromuscular blockade with mechanical ventilation (tidal volume 10 mL x kg(-1)). The staff surgeon, blinded to the type of airway, scored stomach size on an ordinal scale 0-10 at initial insertion of the laparoscope and immediately before the conclusion of the surgical procedure. RESULTS: There were no crossovers and no statistically significant differences between LMA-C/PLMA and ETT groups for SpO(2,) P(ET)CO(2) or airway pressure before or during peritoneal insufflation in short (< or = 15 min) or long (> 15 min) periods of peritoneal inflation. Differences between groups with respect to stomach size changes during surgery were not statistically significant. CONCLUSION: A correctly placed LMA-C or PLMA is as effective as an ETT for positive pressure ventilation without clinically important gastric distension in non-obese and obese patients.

Adult↗
PubMed2002

The LMA-ProSeal is an effective alternative to tracheal intubation for laparoscopic cholecystectomy.

PURPOSE: To compare LMA-ProSeal (LMA-PS) with endotracheal tube (ETT) with respect to pulmonary ventilation and gastric distension during laparoscopic cholecystectomy. METHODS: We randomized 109 ASA I-III adults to LMA-PS or ETT after stratifying them as non-obese or obese (body mass index > 30 kg x m-2). After preoxygenation, anesthesia was induced with propofol, fentanyl and rocuronium. An LMA-PS (women #4, men #5) or ETT (women 7 mm, men 8 mm) was inserted and the cuff inflated. A #14 gastric tube was passed into the stomach in every patient and connected to continuous suction. Anesthesia was maintained with nitrous oxide, oxygen and isoflurane. Ventilation was set at 10 mL x kg-1 and 10 breaths x min-1. The surgeon, blinded to the airway device, scored stomach size on an ordinal scale of 0-10 at insertion of the laparoscope and upon decompression of the pneumoperitoneum. RESULTS: There were no statistically significant differences in SpO2 or P(ET)CO2 between the two groups before or during peritoneal insufflation in either non-obese or obese patients. Median (range) airway pressure at which oropharyngeal leak occurred during a leak test with LMA-PS was 34 (18-45) cm water. Change in gastric distension during surgery was similar in both groups. Four of 16 obese LMA-PS patients crossed over to ETT because of respiratory obstruction or airway leak. CONCLUSIONS: A correctly seated LMA-PS or ETT provided equally effective pulmonary ventilation without clinically significant gastric distension in all non-obese patients. Further studies are required to determine the acceptability of the LMA-PS for laparoscopic cholecystectomy in obese patients.

Adult↗