Utility of premedication with different regimens of omeprazole and ranitidine in the prevention of acid broncho-aspiration syndrome]

OBJECTIVE. To study the usefulness of several omeprazole regimens on gastric fluid volume and pH in patients undergoing elective surgery. MATERIAL AND METHODS. We analyzed 105 patients undergoing to elective surgery who received prophylactic treatment for the acid aspiration syndrome. They were randomly allocated into 7 homogeneous groups according to the therapeutic regime. Placebo (group 1), oral omeprazole (20 mg) the night prior to surgery (group 2), oral ranitidine (150 mg) the night before (group 6), two doses (the previous night and before surgery) in the remaining three groups: 20 mg of omeprazole (group 4), 40 mg of omeprazole (group 5) or 150 mg of ranitidine (group 7). In all patients we measured pH and volume of the gastric content after induction of anesthesia and one hour thereafter. RESULTS. There were no statistically significant differences in mean pH values and gastric volume content among groups 1.2,3, and 6 (2.1 (pH) and 27 ml (gastric volume) in group 1, 2.1 and 23 ml in group 2, 2.6 and 19 ml in group 3, and 2.2 and 32 ml in group 6). With repeated doses of 40 mg omeprazol (group 5), mean pH values were comparable to those found with the two doses of ranitidine (4.1 +/- 1.8 vs 4.1 +/- 3.6) although gastric volumes were significantly less (12 +/- 2.6 ml vs 20 +/- 4.8 ml). These two groups showed significantly greater mean pH values and less gastric volumes than the remaining patients. CONCLUSIONS. The incidence of patients with gastric content deemed at risk for acid aspiration (pH less than 2.5 and gastric volume greater than 25 ml) was less after premedication with two oral doses of omeprazole (40 mg) than either two doses of ranitidine (150 mg) or smaller doses of both drugs.     

Effect of metoclopramide on gastric fluid volumes in diabetic patients who have fasted before elective surgery

BACKGROUND: Diabetes-induced gastroparesis is believed to increase fasting gastric fluid volume before elective surgery. Metoclopramide is routinely administered preoperatively to reduce gastric fluid volume in these patients. This study compared nondiabetic controls to non-insulin-dependent and insulin-dependent diabetics to determine the effect of metoclopramide, administered before surgery, on gastric volumes in patients who fasted before surgery. METHODS: Control and diabetic patients fasted preoperatively before receiving either placebo or 10 mg intravenous metoclopramide 20 min before induction of anesthesia. After intubation, a gastric tube was placed, and stomach contents were aspirated with volumes compared among the groups. RESULTS: Both groups of diabetic patients were older than the control group, and insulin-dependent patients had a higher incidence of comorbidities compared with the non-insulin-dependent group. Fasting blood sugar and hemoglobin A1C values were higher in both insulin-dependent and non-insulin-dependent patients. Gastric fluid volumes were similar in control, non-insulin-dependent, and insulin-dependent patients (8.0 +/- 2.6 vs. 9.6 +/- 4.1 vs. 17.7 +/- 2.5 ml, respectively). In insulin-dependent diabetic patients, metoclopramide decreased gastric volume compared with placebo treatment (17.7 +/- 2.5 vs. 7.8 +/- 2.9 ml; P = 0.027). After stratification, a subpopulation of patients with poorly controlled diabetes, regardless of type, were identified to have increased gastric residual volumes. CONCLUSION: In elective surgical patients who have fasted before surgery, gastric volumes are minimal, even in diabetics with severe neuropathic symptoms. Metoclopramide prophylaxis to reduce gastric volumes seems to be unnecessary unless the patient has a prolonged history of poor blood glucose control.     

Effect of Metoclopramide on Gastric Fluid Volumes in Diabetic Patients Who Have Fasted before Elective Surgery

Background: Diabetes-induced gastroparesis is believed to increase fasting gastric fluid volume before elective surgery. Metoclopramide is routinely administered preoperatively to reduce gastric fluid volume in these patients. This study compared nondiabetic controls to non-insulin-dependent and insulin-dependent diabetics to determine the effect of metoclopramide, administered before surgery, on gastric volumes in patients who fasted before surgery.

Methods: Control and diabetic patients fasted preoperatively before receiving either placebo or 10 mg intravenous metoclopramide 20 min before induction of anesthesia. After intubation, a gastric tube was placed, and stomach contents were aspirated with volumes compared among the groups.

Results: Both groups of diabetic patients were older than the control group, and insulin-dependent patients had a higher incidence of comorbidities compared with the non-insulin-dependent group. Fasting blood sugar and hemoglobin A1C values were higher in both insulin-dependent and non-insulin-dependent patients. Gastric fluid volumes were similar in control, non-insulin-dependent, and insulin-dependent patients (8.0 +/- 2.6 vs. 9.6 +/- 4.1 vs. 17.7 +/- 2.5 ml, respectively). In insulin-dependent diabetic patients, metoclopramide decreased gastric volume compared with placebo treatment (17.7 +/- 2.5 vs. 7.8 +/- 2.9 ml; P = 0.027). After stratification, a subpopulation of patients with poorly controlled diabetes, regardless of type, were identified to have increased gastric residual volumes.     

Comparison of effects of intravenous versus intramuscular famotidine on pH and volume of gastric juice

Famotidine, an H2-antagonist, is frequently used for prevention of acid aspiration in surgical patients. Intravenous as well as intramuscular administration of famotidine has proved effective to reduce gastric acid secretion during anesthesia. However, the onset and duration of action of famotidine following intravenous administration has not been extensively investigated. In the present study on 89 patients undergoing elective surgery, the effects of famotidine 20 mg administered intravenously 5-30 min before endotracheal intubation on pH and volume of gastric contents aspirated 0, 1, 2, and 4 hrs after tracheal intubation and immediately after extubation through nasogastric tube were compared with the effects of the drug administered intramuscularly one hour before endotracheal intubation. Famotidine administered intramuscularly 5-14 min before endotracheal intubation produced inadequate suppression of gastric secretion after tracheal intubation. In contrast, intravenous famotidine given 15-30 min before tracheal intubation, as well as the intramuscular administration of famotidine as premedication, effectively decreased gastric fluid volume and increased gastric pH. Suppression of gastric secretion by intravenous and intramuscular famotidine continued for over 4 hours. Intravenous famotidine has a rapid onset and a long duration of depressant action on gastric secretion, thus reducing the risk of aspiration pneumonitis during and after general anesthesia.     

Gastric fluid pH and volume in gynaecologic out-patients. Influences of cimetidine and cimetidine-sodium citrate combination

Eighty consecutive ASA physical status 1 women scheduled for day-case gynaecological laparoscopy under general anaesthesia were randomly allocated during the pre-operative visit to receive one of four premedication regimes. Patients in group 1 received hydroxyzine 100 mg; patients in group 2 received hydroxyzine 100 mg and cimetidine 400 mg; patients in group 3 received hydroxyzine 100 mg and effervescent cimetidine (cimetidine 200 mg + sodium citrate 1.8 g). All were given orally in 30 ml of water, 90 min before anaesthetic induction. Patients in group 4 received effervescent cimetidine orally in 30 ml of water 5 min before anaesthetic induction. Following induction of anaesthesia, gastric pH and residual volume (phenol red dilution technique) were measured. Gastric pH was higher (P < 0.05) in groups 2, 3 and 4 (medians: 5.71, 4.84, 6.07, respectively) than in group 1 (2.18). No patient had a gastric pH < or = 2.5 in group 4 compared with 13/14 n group 1, 1/15 in group 2 and 2/14 in group 3 (P < 0.0001). Mean gastric volumes were higher (P < 0.05) in group 4 (30.4 +/- 23.2 ml) than in groups 1, 2 and 3 (11.8 +/- 6.4, 15.8 +/- 11.2, 17.2. +/- 24.4 ml, respectively). Nine of the 19 patients in group 4 had a volume higher than 25 ml. Only one patient in group 1 had both gastric pH < or = 2.5 and volume > or = 25 ml. The administration of effervescent cimetidine 5 min prior to anaesthetic induction seems to be an easy and effective method of decreasing the acidity of gastric contents in day surgery.     

Impairment of deglutition reflex after prolonged intubation]

This study was designed to assess the swallowing reflex after an endotracheal intubation of more than 24 h, as well as the influence of age and duration of intubation on swallowing. Twenty patients (aged 58 +/- 17 years) who had been intubated for more than 24 h were compared with fifteen others (63.1 +/- 16.7 years), who had never been intubated. All had a nasogastric tube. Swallowing was assessed after administration of 0.25, 0.5, 0.75 and 1 ml volumes of normal saline, in a random sequence, into the epipharynx through a thin catheter passing through the nostril after extubation (E0), and then at 1 (E1), 8 (E8), 24 (E24) and 48 h (E48) in the extubated patients, and once in the control patients. Swallowing responses were identified by an electromyogram of the floor of the oral cavity. The efficiency of the swallowing reflex was assessed by the delay between instillation and the first swallowing response obtained, and the number of swallows recorded during the first 15 seconds following each injection. There was a significant increase in swallowing delay in intubated patients for volumes less than 1 ml during the first three measurements. Recovery occurred for 0.5 and 0.75 ml at E24 and E48, when compared with the control group. However, delay remained increased throughout the study for 0.25 ml. The number of swallows was the same in both groups for each volume tested. There was no correlation between increased delay and age or duration of intubation. These data confirmed that prolonged endotracheal intubation impairs the swallowing reflex.(ABSTRACT TRUNCATED AT 250 WORDS)     

Time required for oral ranitidine to decrease gastric fluid acidity

This study documented gastric fluid acidity in ambulatory surgical patients 30-120 min after they had taken a 300-mg tablet of ranitidine, as changes specific to this relatively brief dose-to-sampling interval previously had not been delineated. At 20-120 min before outpatient surgery, ranitidine was given with 15 mL of water to 112 ASA physical status I-III adults without increased risk factors for aspiration of acidic gastric contents. After induction of general endotracheal anesthesia, the gastric fluid was aspirated. Volume and pH were compared with a reference group (pH = 1.6 +/- 1; n = 161) that did not receive an H2-antagonist or water. Of 40 patients sampled at 30-60 min after dosing, 26 had pH greater than or equal to 2.5; mean pH was 3.9 +/- 2 (P less than 0.05 vs reference by Wilcoxon signed rank and chi 2 tests). Beyond 90 min, 28 of 28 patients had a pH greater than or equal to 2.5, with a mean of 6.3 +/- 1. No significant differences were noted with respect to mean gastric volume. We conclude that in patients without additional risk factors, oral ranitidine consistently prevents acid production when it is administered more than 90 min before induction of anesthesia.     

Effects of pre-anaesthetic glycopyrrolate and cimetidine on gastric fluid acidity and volume in children

The effects of pre-anaesthetic glycopyrrolate and cimetidine on gastric fluid pH and volume were studied in 96 paediatric patients from ages 6 months to 12 years undergoing elective surgery. They were randomly allocated into six groups with 16 patients in each group. Patients in group I received neither glycopyrrolate nor cimetidine and served as controls. Group II patients received glycopyrrolate, 5 micrograms kg-1 intramuscularly in a.m. Patients in group III received cimetidine 5 mg kg-1 orally in a.m. Group IV patients received cimetidine 5 5 mg kg-1 orally in a.m. and glycopyrrolate 5 micrograms kg-1 in a.m. Patients in group V received cimetidine 5 mg kg-1 orally h.s. and a.m. Group VI patients received cimetidine as in group V and also received glycopyrrolate as in group II. Patients with gastric pH 2.5 or less and volume of gastric contents 0.4 ml kg-1 or greater were defined to be at risk of pulmonary damage if aspiration should occur. The patients in the control group had a mean gastric pH of 1.91 +/- 0.074 and mean gastric volumes of 0.52 +/- 0.06 ml kg-1. Ninety-four per cent of patients in this group had gastric pH less than or equal to 2.5 and 69% of patients had gastric volumes greater than or equal to 0.4 ml kg-1. Glycopyrrolate (group II) reduced patients with pH less than or equal to 2.5 to 50% and volumes greater than or equal to 0.4 ml kg-1 to 44%. Cimetidine markedly reduced both gastric acidity (gastric pH less than or equal to 2.5 in 0-13% of patients in groups III-VI) and gastric volume (greater than or equal to 0.4 ml kg-1 in 19-38% of patients in groups III-VI). Only a maximum of 13% of the patients presented with combination of both risk factors in groups III-VI.(ABSTRACT TRUNCATED AT 250 WORDS)     

Large volumes of apple juice preoperatively do not affect gastric pH and volume in children

The effect on gastric pH and volume of 0, 6 and 10 ml.kg-1, of apple juice given 2.5 hours before surgery to children aged five to ten years was investigated in this prospective, randomized, single-blind study. Gastric contents were aspirated after induction of anaesthesia, and the volume measured. The pH of the gastric aspirate was then assessed using pH paper. Neither gastric volume nor pH immediately following the induction of general anaesthesia were significantly different among the three groups. Gastric volumes after 0, 6 and 10 ml.kg-1, of juice averaged (mean +/- SD) 0.45 +/- 0.31, 0.66 +/- 0.79 and 0.71 +/- 0.76 ml.kg-1, respectively; gastric pH averaged 1.7 +/- 0.6, 1.7 +/- 0.6 and 1.8 +/- 0.8, respectively. On the basis of questions asked immediately before induction of anaesthesia, patients who drank 6 ml.kg-1 of apple juice had decreased thirst and were less irritable and upset before anaesthesia than those who had not (P less than 0.05). It is concluded that drinking large volumes of clear apple juice 2.5 hours before scheduled surgery does not have a measurable effect on gastric volume and pH and may offer benefits such as improved patient comfort.     

Gastric volume and acidity at caesarean section.

The pulmonary acid aspiration (Mendelson's) syndrome may present after regurgitation and inhalation of acid gastric content during obstetric anesthesia. The stomach contents of 70 mothers were aspirated at caesarean section after pre-operative gastric 'emptying' and alkaline ingestion. The acidity of the gastric aspirate was analysed and volumes were measured. The patients were divided into 5 groups according to the time when gastric aspiration was carried out. A 'safe' gastric pH (pH greater than 3.5) was found in all patients up to 2 hours after antacid ingestion (groups 1-3). However, 2 1/2 hours after antacid ingestion (group 4y, 50% of patients had gastric volumes in excess of 25 ml and a pH of less than 3.5. We therefore recommend that, if general anaesthesia is to be induced or is in progress 2 hours after antacid therapy, the alkaline regimen should be resumed after repeated gastric aspiration.     

食管引流型喉面罩对全麻腹腔镜卵巢囊肿剥除术麻醉质量的影响

目的:探讨食管引流型喉面罩在全麻腹腔镜卵巢囊肿剥除术中对麻醉质量的影响。方法:选择全麻腹腔镜卵巢囊肿手术患者90例,ASAⅠ级,随机分为插管组(n=45)和喉面罩组(n=45)。监测两组患者诱导插管前(T0)、诱导插管时(T1)、气腹时(T2)、苏醒拔管时(T3)、苏醒拔管后20min(T4)的平均动脉血压(MAP)、心率(HR)、血氧饱和度(SpO2)、呼气末二氧化碳分压(PETCO2)等变化,并于上述各时点抽取动脉血检测术中血气分析变化,观察患者围手术期呼吸系统等并发症的发生情况。结果:(1)术中SpO2、PETCO2无显著性差异(P>0.05);(2)两组T1、T2时MAP与T0比较均显著性降低(P<0.05),组间无显著性差异(P>0.05);插管组T3、T4时与T0比较MAP显著性升高(P<0.05),喉面罩组无显著性差异(P>0.05);(3)两组HR于T1、T2、T3、T4时与T0比较均显著性升高(P<0.05),T1、T3时插管组高于喉面罩组(P<0.05);(4)两组患者T2时与T1、T3比较,PETCO2、气道压力(Paw)略有升高,喉面罩组高于插管组(P>0.05);(5)喉面罩组T3时pH、PCO2与T0及插管组比较,略有升高,但无显著性差异(P>0.05);(6)术后插管组咽喉痛、声音嘶哑、咳嗽等情况的发生率高于喉面罩组(P<0.05)。结论:食管引流型喉面罩在全麻腹腔镜卵巢囊肿切除术中可提高围手术期麻醉质量,患者血流动力学稳定,围手术期并发症少,比较适合在全麻妇科腹腔镜短小手术中应用。     

Comparison of preoperative gastric contents and serum gastrin concentrations in pregnant and nonpregnant women

STUDY OBJECTIVE: The aim of this study was to compare the volume and the pH level of preoperative gastric contents and serum gastrin concentrations between pregnant and nonpregnant women. DESIGN: This prospective controlled study was conducted in a single blind manner. PATIENTS: One hundred pregnant women scheduled for elective cesarean delivery (pregnant group) and 100 nonpregnant women who underwent gynecologic surgery (nonpregnant group) were enrolled. INTERVENTIONS: Gastric content was aspirated gently with 14-F multiorificed nasogastric tube before the induction of anesthesia. MEASUREMENTS: The volume and the pH level of the aspirated gastric contents were measured, and serum gastrin concentration was measured by the double antibody gastrin method. MAIN RESULTS: The gastric volume in the pregnant group was greater than in the nonpregnant group (0.49 +/- 0.4 vs 0.24 +/- 0.2 mL/kg, P < .05). The gastric pH level in the pregnant group was lower than in the nonpregnant group (2.4 +/- 1.4 vs 3.0 +/- 1.9, P < .05). The number of patients at risk was 45 (45.5%) in the pregnant group and 16 (16.7%) in the nonpregnant group (P < .05). The serum gastrin levels of the 2 groups were not significantly different (32.1 +/- 12.3 vs 28.2 +/- 8.3 pg/mL). The preoperative anxiety level of the pregnant group was higher than in the nonpregnant group (4.4 +/- 2.1 vs 3.8 +/- 2.2, P < .05). CONCLUSIONS: We confirmed that pregnant women have much greater and more acidic gastric contents than the nonpregnant patients preoperatively, and it is not because of serum gastrin concentration.     

A comparison of intravenous ranitidine and omeprazole on gastric volume and pH in women undergoing emergency Caesarean section

We have compared the effect of intravenously administered omeprazole and ranitidine on gastric contents in a double-blind study in 80 consecutive women undergoing emergency Caesarean section. When the decision to perform emergency Caesarean section was made, patients were randomly assigned to receive either ranitidine 50 mg or omeprazole 40 mg intravenously. The volume and pH of the gastric contents were measured immediately after tracheal intubation and again before extubation. The gastric pH was found to be higher after omeprazole than after ranitidine immediately after intubation (5.89 ± 1.46 and 5.21 ± 1.36 respectively) (P < 0.05) and before extubation (5.97 ± 1.38 and 5.32 ± 1.24 respectively) (P < 0.05). However, the gastric volumes were comparable in both the groups. The number of patients with gastric volume > 25 ml and pH < 2.5 were 3 (7.5%) in the ranitidine group and 1 (2.5%) in the omeprazole group after intubation and none in either of the groups before extubation. We conclude that omeprazole 40 mg iv administered at the time of the decision to operate, results in higher gastric pH than ranitidine in obstetric patients undergoing emergency Caesarean section. Une étude à double insu nous a permis de comparer l’effet de l’oméprazole et de la ranitidine sur le contenu gastrique de 80 parturientes subissant une césarienne d’urgence. Au moment de h prise de décision en faveur de la césarienne, les patientes ont été réparties aléatoirement pour recevoir soit de la ranitidine 50 mg, soit de l’oméprazole 40 mg par la voie intraveineuse. Le volume et le pH du contenu gastrique ont été mesurés immédiatement après l’intubation et avant l’extubation. Le pH gastrique était plus élevé après l’oméprazole qu’après la ranitidine immédiatement après l’intubation (respectivement 5,89 ± 1,46 et 5,21 ± 1,36, P < 0,05) et avant l’extubation (respectivement 5,97 ± 1,38 et 5,32 ± 1,24, P < 0,05). Cependant, le volume gastrique était comparable entre les deux groupes. Après l’intubation, le nombre de patientes avec un volume gastrique > 25 ml et un pH <2,5 était de trois (7,5%) dans le groupe ranitidine, et de une (2,5%) dans le groupe omeprazole et d’aucune des deux groupes avant l’extubation. Les auteurs concluent que l’oméprazole 40 mg iv administré au moment de la décision d’opérer procurait un pH gastrique plus élevé que la ranitidine chez des parturientes subissant une césarienne en urgence.     

The effects of intravenous cimetidine and metoclopramide on gastric pH and volume in outpatients

STUDY OBJECTIVE: To evaluate and compare the preinduction effects of intravenously (IV) administered cimetidine alone and combined with metoclopramide on gastric contents and postoperative nausea and vomiting in outpatients undergoing elective surgery. DESIGN: Patients were allocated randomly to 4 groups with 20 patients in each group. SETTING: Ambulatory surgery at a university-affiliated city hospital. PATIENTS: Eighty patients undergoing elective gynecologic or orthopedic procedures were studied. INTERVENTIONS: Outpatients in Group 1 and inpatients in Group 2 served as controls. Outpatients in Group 3 received 300 mg of cimetidine, and outpatients in Group 4 received 300 mg of cimetidine and 10 mg of metoclopramide. All drugs were administered IV as an infusion over a 15-minute period, 30 to 45 minutes prior to induction of anesthesia. MEASUREMENTS AND MAIN RESULTS: After induction of general anesthesia and endotracheal intubation, stomach contents were retrieved and volume and pH measured. Group 1 outpatients had a large residual gastric volume of 29.2 +/- 15.9 ml, with a very low pH of 2.32 +/- 1.23 and 15% frequency of postoperative vomiting. These patients are at high risk of developing significant pneumonitis in the event of the aspiration of gastric contents. The combination of cimetidine and metoclopramide in Group 4 provided the optimal, or safest, condition--i.e., high gastric pH [6.15 +/- 0.71 (p less than 0.005)] and low gastric volume [11.6 +/- 7.37 ml (p less than 0.001)], with no postoperative vomiting. CONCLUSIONS: The combination of cimetidine and metoclopramide given to ambulatory patients during the preinductive phase may prevent severe pulmonary consequences should aspiration occur and is more effective in this regard than cimetidine alone.     

Pharmacologic prevention of Mendelson syndrome. A controlled clinical trial]

This controlled study considers the effect of ranitidine, both alone and in association with metoclopramide, on the acidity and volume of the gastric content of 75 patients requiring caesarean section. Ranitidine, when used alone (50 mg intravenously 30-60 minutes before the operation) significantly reduced (p less than 0.01) the acidity (pH greater than 2.5) and the volume (less than 25 ml) of the gastric content of the patient thus treated. Ranitidine in association with metoclopramide may also reduce the pH and the volume, but did not show any significant statistical differences when compared with the use of ranitidine alone.     

Occurrence of gastroesophageal reflux on induction of anaesthesia does not correlate with the volume of gastric contents

In an attempt to explain the discrepancy between the high number of patients said to be at risk of aspiration pneumonitis and the low reported incidence of this anaesthetic complication, 100 ASA physical status I-II elective surgical patients were studied. The volume of fluid present in the stomach at the time of induction of anaesthesia was correlated with gastroesophageal reflux (GER) detected by visual inspection of the pharynx and by continuous measurement of upper oesophageal pH. Mean gastric volume was 30 +/- 28 ml (range 0-210 ml). Gastric fluid volume greater than or equal to 0.4 ml.kg-1 at pH less than or equal to 2.5 was present in 46 patients. No GER was detected during induction of anaesthesia in our sample of 100 patients. Furthermore, patient age, duration of preoperative fasting, body mass index, cigarette smoking, alcohol consumption, preoperative anxiety, and a history of preoperative GER were not correlated with significant modifications of gastric volume or pH. We conclude that the low incidence of aspiration pneumonitis in elective surgical patients may be explained in part by the very low risk of GER, despite gastric fluid volumes of more than 0.4 ml.kg-1 in a high proportion of this patient population.     

A double-blind comparison of cimetidine and ranitidine as prophylaxis against gastric aspiration syndrome

Preoperative cimetidine, ranitidine, or placebo were administered, orally or intravenously to 190 patients in a double-blind study. The volume and pH of gastric aspirate samples, obtained after tracheal intubation and before extubation, were measured. Both cimetidine and ranitidine produced higher mean pH levels and thus fewer patients "at risk" should gastric aspiration occur (pH less than or equal to 2.5) than did placebo. Intravenous ranitidine (in both 40- and 80-mg doses) produced fewer patients at risk in the event gastric aspiration should occur than did cimetidine, 300 mg, and the 80-mg dose produced a higher mean pH level. Oral ranitidine, 150 mg, produced a significantly higher mean pH level than did oral cimetidine, 300 mg, and tended to give fewer patients at risk. The volumes of gastric contents aspirated were similar following each of the drugs except that the volume was significantly less two hours following oral ranitidine, 150 mg, than after oral cimetidine, 300 mg.     

Effects of oral cimetidine and ranitidine on gastric pH and residual volume in children

The effect of orally administered cimetidine 7.5 mg/kg (group 1), ranitidine 1.5 mg/kg (group 2), ranitidine 2.0 mg/kg (group 3), or a placebo (group 4) on gastric pH and gastric residual volume of 60 healthy children 2-6 yr of age admitted for elective surgery was evaluated. Both cimetidine and ranitidine administered 1-2 h prior to induction of anesthesia effectively increased the gastric pH:5,47 - 1.85 ml/kg (group 1), 4.92 +/- 2.1 ml/kg (group 2), 5.30 +/- 1.82 ml/kg (group 3) compared with 1.75 +/- 0.58 ml/kg (group 4) (P less than 0.001). A single dose of ranitidine 1.5 mg/kg was an effective as ranitidine 2.0 mg/kg and cimetidine 7.5 mg/kg. Neither drug decreased the gastric residual volume: 0.32 +/- 0.33 ml/kg (group 1), 0.31 +/- 0.06 ml/kg (group 2), 0.23 +/- 0.05 ml/kg (group 3), and 0.33 +/- 0.05 ml/kg (group 4). The combination of a volume greater than 0.4 ml/kg and a pH less than 2.5 was found in 33% (five of 15) of patients in the placebo group (group 4). In contrast, there were no patients with this combination in groups 1, 2, or 3 (P less than 0.001).     

Antacid anticholinergic regimens in patients undergoing elective caesarean section

The pH and volume of gastric contents were examined in 60 patients undergoing elective Caesarean Section under thiopentone, nitrous oxide-oxygen, succinylcholine anaesthesia. All patients received Gelusil 30 ml per os preoperatively, while 20 were given atropine 7 microgram X kg-1 and another 20 glycopyrrolate 4 microgram X kg-1 intramuscularly along with Gelusil. Following tracheal intubation, gastric fluid was sampled through an orally placed 18 French Salem Sump tube. After Gelusil alone, the mean gastric fluid pH was 4.54 +/- 2.45 (SD) while it was significantly higher following the combined use of antacid and atropine (6.78 +/- 1.20) or antacid and glycopyrrolate (6.42 +/- 1.72), (P less than 0.01). Differences in gastric fluid volume between the groups were insignificant. All three regimens produced a gastric pH greater than 2.5 when given less than 75 minutes before sampling. When the premedication to sampling interval exceeded 75 minutes the addition of atropine or glycopyrrolate decreased the incidence of gastric pH less than 2.5 from 47 per cent in patients given Gelusil alone to 6 per cent and 14 per cent, respectively. In comparison to Gelusil alone, this difference was significant with atropine (P less than 0.05) but not with glycopyrrolate. Atropine and glycopyrrolate respectively produced 6 per cent and 7 per cent incidences of pH lower than 2.5 combined with gastric volume greater than 25 ml, which were significantly lower than was observed with Gelusil alone (P less than 0.05). This study demonstrates that the addition of atropine or glycopyrrolate to Gelusil premedication provides additional protection against the consequences of aspiration, especially when the premedication to anaesthetic induction period is prolonged.     

The effect of preoperative apple juice on gastric contents,thirst, and hunger in children

The effect of 3 ml.kg-1 of apple juice given 2.6 +/- 0.4 hours preoperatively was investigated in 80 healthy children of ages five to ten years in this prospective, randomized, single blind study. The children who drank apple juice preoperatively had decreased gastric volume, thirst, and hunger (p less than 0.05). The gastric volume in the control group was 0.43 +/- 0.46 ml.kg-1 and in the patients who received apple juice the gastric volume was 0.24 +/- 0.31 ml.kg-1. The gastric pH was not significantly different, with the control group's gastric pH being 1.7 +/- 0.6 and the treated group's pH was 2.2 +/- 1.2. Further studies of the effects of different volumes and timing of preoperative clear fluids are indicated in paediatric patients.